# The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources

Martin Gericke, Adérito J R Amaral, Tatiana Budtova, Pieter de Wever, Thomas Groth, Thomas Heinze, Herman Höfte, Anton Huber, Olli Ikkala, Janusz Kapuśniak, et al.

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Martin Gericke, Adérito J R Amaral, Tatiana Budtova, Pieter de Wever, Thomas Groth, et al. The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources. Carbohydrate Polymers, 2023, 326, pp.121633. 10.1016/j.carbpol.2023.121633. hal-04372852

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# The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources

Martin Gericke, Adérito J.R. Amaral, Tatiana Budtova, Pieter de Wever, Thomas Groth, Thomas Heinze, Herman Höfte, Anton Huber, Olli Ikkala, Janusz Kapuśniak, et al.

► To cite this version:

Martin Gericke, Adérito J.R. Amaral, Tatiana Budtova, Pieter de Wever, Thomas Groth, et al. The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources. Carbohydrate Polymers, 2023, 326, pp.121633. 10.1016/j.carbpol.2023.121633. hal-04372852

HAL Id: hal-04372852

https://hal.inrae.fr/hal-04372852v1

Submitted on 4 Jan 2024

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# The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources

Martin Gericke<sup>a</sup>, Adérito J.R. Amaral<sup>b</sup>, Tatiana Budtova<sup>c</sup>, Pieter De Wever<sup>d</sup>, Thomas Groth<sup>e</sup>, Thomas Heinze<sup>a</sup>, Herman Höfte<sup>f</sup>, Anton Huber<sup>g</sup>, Olli Ikkala<sup>h</sup>, Janusz Kapuśniak<sup>i</sup>, Rupert Kargl<sup>j</sup>, João F. Mano<sup>b</sup>, Már Másson<sup>k</sup>, Pietro Matricardi<sup>l</sup>, Bruno Medronho<sup>m,n</sup>, Magnus Norgren<sup>n</sup>, Tiina Nypelö<sup>o,p</sup>, Laura Nyström<sup>q</sup>, Anna Roig<sup>r</sup>, Michael Sauer<sup>s,1</sup>, Henk A. Schols<sup>t</sup>, John van der Linden<sup>u</sup>, Tanja M. Wrodnigg<sup>j</sup>, Chunlin Xu<sup>v</sup>, Gleb E. Yakubov<sup>w</sup>, Karin Stana Kleinschek<sup>j,*</sup>, Pedro Fardim<sup>d</sup>

## ARTICLE INFO

### Keywords:

Bioeconomy

Polysaccharides

Food and nutrition

Biomaterials

Biomedical applications

## ABSTRACT

Polysaccharides are among the most abundant bioresources on earth and consequently need to play a pivotal role when addressing existential scientific challenges like climate change and the shift from fossil-based to sustainable biobased materials. The Research Roadmap 2040 of the European Polysaccharide Network of Excellence (EPNOE) provides an expert's view on how future research and development strategies need to evolve to fully exploit the vast potential of polysaccharides as renewable bioresources. It is addressed to academic researchers, companies, as well as policymakers and covers five strategic areas that are of great importance in the context of

<footnote><sup>a</sup> Friedrich Schiller University of Jena, Institute of Organic Chemistry and Macromolecular Chemistry, Centre of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany</footnote>

<footnote><sup>b</sup> Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal</footnote>

<footnote><sup>c</sup> MINES Paris, PSL University, CEMEF - Center for Materials Forming, UMR CNRS 7635, CS 10207, rue Claude Daumesse, 06904 Sophia Antipolis, France</footnote>

<footnote><sup>d</sup> KU Leuven, Department of Chemical Engineering, Chemical and Biochemical Reactor Engineering and Safety (CREaS), Celestijnenlaan 200F, 3001 Leuven, Belgium</footnote>

<footnote><sup>e</sup> Department Biomedical Materials, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale), Germany</footnote>

<footnote><sup>f</sup> Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France</footnote>

<footnote><sup>g</sup> University Graz, Inst.f. Chem./PS&HC - Polysaccharides & Hydrocolloids, Heinrichstrasse 28, 8010 Graz, Austria</footnote>

<footnote><sup>h</sup> Department of Applied Physics, Aalto University School of Science, FI-00076 Espoo, Finland</footnote>

<footnote><sup>i</sup> Jan Dlugosz University in Czestochowa, Faculty of Science and Technology, Department of Dietetics and Food Studies, Waszyngtona 4/8, 42-200 Czestochowa, Poland</footnote>

<footnote><sup>j</sup> Graz University of Technology, Institute of Chemistry and Technology of Biobased Systems, Stremayrgasse 9, A-8010 Graz, Austria</footnote>

<footnote><sup>k</sup> Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavík, Iceland</footnote>

<footnote><sup>l</sup> Sapienza University of Rome, Department of Drug Chemistry and Technologies, P.le A. Moro 5, 00185 Rome, Italy</footnote>

<footnote><sup>m</sup> MED—Mediterranean Institute for Agriculture, Environment and Development, CHANGE—Global Change and Sustainability Institute, Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal</footnote>

<footnote><sup>n</sup> Surface and Colloid Engineering, FSCN Research Center, Mid Sweden University, SE-851 70 Sundsvall, Sweden</footnote>

<footnote><sup>o</sup> Chalmers University of Technology, Department of Chemistry and Chemical Engineering, 41296 Gothenburg, Sweden</footnote>

<footnote><sup>p</sup> Aalto University, Department of Bioproducts and Biosystems, 00076 Aalto, Finland</footnote>

<footnote><sup>q</sup> ETH Zurich, Department of Health Sciences and Technology, Schmelzbergstrasse 9, 8092 Zurich, Switzerland</footnote>

<footnote><sup>r</sup> Institute of Materials Science of Barcelona (ICMAB-CSIC), 08193 Bellaterra, Spain</footnote>

<footnote><sup>s</sup> University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria</footnote>

<footnote><sup>t</sup> Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708WG Wageningen, the Netherlands</footnote>

<footnote><sup>u</sup> Becoming-Aware, D'Hoogvorstlaan 30, 1860 Meise, Belgium</footnote>

<footnote><sup>v</sup> Åbo Akademi University, Laboratory of Natural Materials Technology, Henrikinkatu 2, Turku/Åbo, Finland</footnote>

<footnote><sup>w</sup> Soft Matter Biomaterials and Biointerfaces, Food Structure and Biomaterials Group, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom</footnote>

<footnote>* Corresponding author.</footnote>

<footnote>E-mail address: karin.stanakleinschek@tugraz.at (K. Stana Kleinschek).</footnote>

<footnote n="1">¹ Present address: OMV AG, Trabrennstr. 6-8, 1020 Vienna, Austria.</footnote>
<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /></figure>

# The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources

Martin Gericke<sup>a</sup>, Adérito J.R. Amaral<sup>b</sup>, Tatiana Budtova<sup>c</sup>, Pieter De Wever<sup>d</sup>, Thomas Groth<sup>e</sup>, Thomas Heinze<sup>a</sup>, Herman Höfte<sup>f</sup>, Anton Huber<sup>g</sup>, Olli Ikkala<sup>h</sup>, Janusz Kapuśniak<sup>i</sup>, Rupert Kargl<sup>j</sup>, João F. Mano<sup>b</sup>, Már Másson<sup>k</sup>, Pietro Matricardi<sup>l</sup>, Bruno Medronho<sup>m,n</sup>, Magnus Norgren<sup>n</sup>, Tiina Nypelö<sup>o,p</sup>, Laura Nyström<sup>q</sup>, Anna Roig<sup>r</sup>, Michael Sauer<sup>s,1</sup>, Henk A. Schols<sup>t</sup>, John van der Linden<sup>u</sup>, Tanja M. Wrodnigg<sup>j</sup>, Chunlin Xu<sup>v</sup>, Gleb E. Yakubov<sup>w</sup>, Karin Stana Kleinschek<sup>j,*</sup>, Pedro Fardim<sup>d</sup>

## ARTICLE INFO

**Keywords:**

Bioeconomy

Polysaccharides

Food and nutrition

Biomaterials

Biomedical applications

## ABSTRACT

Polysaccharides are among the most abundant bioresources on earth and consequently need to play a pivotal role when addressing existential scientific challenges like climate change and the shift from fossil-based to sustainable biobased materials. The Research Roadmap 2040 of the European Polysaccharide Network of Excellence (EPNOE) provides an expert's view on how future research and development strategies need to evolve to fully exploit the vast potential of polysaccharides as renewable bioresources. It is addressed to academic researchers, companies, as well as policymakers and covers five strategic areas that are of great importance in the context of

<footnote><sup>a</sup> Friedrich Schiller University of Jena, Institute of Organic Chemistry and Macromolecular Chemistry, Centre of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany</footnote>

<footnote><sup>b</sup> Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal</footnote>

<footnote><sup>c</sup> MINES Paris, PSL University, CEMEF - Center for Materials Forming, UMR CNRS 7635, CS 10207, rue Claude Daumesse, 06904 Sophia Antipolis, France</footnote>

<footnote><sup>d</sup> KU Leuven, Department of Chemical Engineering, Chemical and Biochemical Reactor Engineering and Safety (CREaS), Celestijnenlaan 200F, 3001 Leuven, Belgium</footnote>

<footnote><sup>e</sup> Department Biomedical Materials, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale), Germany</footnote>

<footnote><sup>f</sup> Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France</footnote>

<footnote><sup>g</sup> University Graz, Inst.f. Chem./PS&HC - Polysaccharides & Hydrocolloids, Heinrichstrasse 28, 8010 Graz, Austria</footnote>

<footnote><sup>h</sup> Department of Applied Physics, Aalto University School of Science, FI-00076 Espoo, Finland</footnote>

<footnote><sup>i</sup> Jan Dlugosz University in Czestochowa, Faculty of Science and Technology, Department of Dietetics and Food Studies, Waszyngtona 4/8, 42-200 Czestochowa, Poland</footnote>

<footnote><sup>j</sup> Graz University of Technology, Institute of Chemistry and Technology of Biobased Systems, Stremayrgasse 9, A-8010 Graz, Austria</footnote>

<footnote><sup>k</sup> Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavík, Iceland</footnote>

<footnote><sup>l</sup> Sapienza University of Rome, Department of Drug Chemistry and Technologies, P.le A. Moro 5, 00185 Rome, Italy</footnote>

<footnote><sup>m</sup> MED—Mediterranean Institute for Agriculture, Environment and Development, CHANGE—Global Change and Sustainability Institute, Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal</footnote>

<footnote><sup>n</sup> Surface and Colloid Engineering, FSCN Research Center, Mid Sweden University, SE-851 70 Sundsvall, Sweden</footnote>

<footnote><sup>o</sup> Chalmers University of Technology, Department of Chemistry and Chemical Engineering, 41296 Gothenburg, Sweden</footnote>

<footnote><sup>p</sup> Aalto University, Department of Bioproducts and Biosystems, 00076 Aalto, Finland</footnote>

<footnote><sup>q</sup> ETH Zurich, Department of Health Sciences and Technology, Schmelzbergstrasse 9, 8092 Zurich, Switzerland</footnote>

<footnote><sup>r</sup> Institute of Materials Science of Barcelona (ICMAB-CSIC), 08193 Bellaterra, Spain</footnote>

<footnote><sup>s</sup> University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria</footnote>

<footnote><sup>t</sup> Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708WG Wageningen, the Netherlands</footnote>

<footnote><sup>u</sup> Becoming-Aware, D'Hoogvorstlaan 30, 1860 Meise, Belgium</footnote>

<footnote><sup>v</sup> Åbo Akademi University, Laboratory of Natural Materials Technology, Henrikinkatu 2, Turku/Åbo, Finland</footnote>

<footnote><sup>w</sup> Soft Matter Biomaterials and Biointerfaces, Food Structure and Biomaterials Group, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom</footnote>

<footnote>* Corresponding author.</footnote>

<footnote>E-mail address: karin.stanakleinschek@tugraz.at (K. Stana Kleinschek).</footnote>

<footnote n="1">¹ Present address: OMV AG, Trabrennstr. 6-8, 1020 Vienna, Austria.</footnote>
polysaccharide related research: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology & Physics, and (V) Skills & Education. Each section summarizes the state of research, identifies challenges that are currently faced, project achievements and developments that are expected in the upcoming 20 years, and finally provides outlines on how future research activities need to evolve.

# 1. Introduction

Polysaccharides are among the most abundant biological and renewable materials on our planet (Fig. 1). They are present in our everyday life in the form of energy storage, food, textiles, packaging, construction materials, and medicines. Polysaccharides will be central to the world of tomorrow as a transition to sustainable technologies is crucial for the future of humanity. Proper utilisation of polysaccharide resources has the potential to increase biodiversity, enhance food safety and sustainability, and decrease CO₂ emissions and pollution. Three main drivers strongly push the use of polysaccharides:

- the emergence of a bioeconomy that increases the contribution of biobased products

- the fact that these are polymers with various exceptional properties, opening routes for novel applications in all sectors of human activities such as materials science, nutrition, health, personal care, and energy

- the renewable character of polysaccharides, making them primary CO₂ neutral candidates for the global transformation to a more sustainable world.

To unfold the sustainable future of polysaccharides, a series of joint efforts in science, technology, education, and policy will be needed. The first step was already taken in 2007 when the European Polysaccharide Network of Excellence (EPNOE) Association was established with the support of the European Commission (EC). For 15 years, we have built a unique collaborative environment for scientists, institutions, and companies. Today, EPNOE is a vibrant organization with >50 institutions and companies from 20 countries. This unique international joint venture involving science, education and business inspired us to take the next step and create a visionary interdisciplinary document.

The EPNOE Research Roadmap presented herein is a joint collaborative effort of scientists from 13 European countries with the goal to build a unique vision of experts for the future of polysaccharide research and education in Europe and globally. The document has five strategic areas covering: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Fundamental Sciences (i.e., Chemistry, Biology & Physics), and (V) Skills & Education.

## 1.1. About the European Polysaccharide Network of Excellence (EPNOE)

EPNOE (www.epnoe.eu) was established in May 2005 as a Network of Excellence with funding from the EC under the FP6-NMP program Grant Agreement ID: 500375. This network instrument was designed to reduce fragmentation and strengthen competitiveness by assembling a critical mass of resources and expertise centered on various fields of science and technology (in our case polysaccharides). The ambition for this network was to continue to exist and grow on a long-term basis. To reach this goal, EPNOE was registered as a non-profit association in December 2007 and continued its activities after the end of EC funding in October 2009.

The initial focus of EPNOE was on promoting the use of polysaccharides as industry feedstock for the manufacturing of advanced, multifunctional materials. In March 2012, it received further funding from the EC for three years under the FP7-NMP program Grant Agreement ID: 290486 to expand activities towards health- and food-related materials and products as well as to increase industrial participation and innovation. EPNOE has continued after the end of the second period

of EC funding in February 2015 and now sustains its activities from membership fees. The network, which began with 16 academic and research institutions from 9 European countries, has grown to include >50 academic, research and industry institutions from all around the world.

## 1.2. Polysaccharides and biomass in the global perspective

Polysaccharides are defined as polymeric compounds consisting of a large number of monosaccharides that are linked through glycosidic bonds (IUPAC, 1997). They are frequently also referred to as *glycans*. As such, polysaccharide research can be considered as part or extension of *glycoscience*, a branch of research that focusses on carbohydrates (mono-, oligo-, and polysaccharides) as well as assemblies of carbohydrates with other compounds such as proteins (Barchi, 2021; National Research Council Committee on Assessing the Importance and Impact of Glycomics and Glycosciences, 2012). Polysaccharides are produced in large quantities by plants but also by microorganisms and animals and are consequently considered as highly valuable renewable resources. It is accepted that the amounts of oil, coal, and gas that we have been using as our major energy sources since the industrial revolution cannot be easily substituted. Their use, however, impacts society, climate, and politics. It causes pollution, and is regarded as non-sustainable at the current rate of consumption. Fossil carbon use is complemented by our growing global consumption of biomass for food, energy, and materials (Krausmann et al., 2013). This biomass is, in turn, essential for the preservation of biodiversity, land, water resources, and human health. In any case, fossil carbon deposits and biomass are an integral part of the global carbon cycle. Solutions to the current instability of the climate system, to pollution, biodiversity loss, and to rising global demands must include the right treatment of fossil-based and bioresources.

Biomass and polysaccharides are seen as attractive resources because they are almost exclusively based on a fascinating circular mode of production of photosynthetically captured carbon dioxide, with water as the reductant. Despite the essential importance of biomass, the limited per capita amounts that are available with current technology and land-use schemes also cause controversies among scientists, policymakers, and the public about the role of biomass in mitigating global challenges (Bar-On, Phillips, & Milo, 2018). Concerns are raised that an ever-increasing industrial use of biogenic raw materials, and a growing demand for food, will lead to reduced biodiversity, destruction of ecosystems, and harm the global climate. Fig. 2 summarizes different opinions on the role and use of biomass in more sustainable economic systems as related to climate actions (Strengers & Elzenga, 2020). Strategies for prudent use of biomass and polysaccharides are therefore of utmost importance, and no simple solution exists. Significant research efforts are needed to understand biosynthesis, structural variations, material properties, and the influence of biomass on health, ecology, and societies. Furthermore, new technologies might be necessary to increase or modify biomass production and how it is produced, used, recycled, and discarded.

One of the objectives of the EPNOE Research Roadmap was to assess the availability of biomass (with a focus on polysaccharides) according to the current scientific literature. Annual terrestrial global
polysaccharide related research: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology & Physics, and (V) Skills & Education. Each section summarizes the state of research, identifies challenges that are currently faced, project achievements and developments that are expected in the upcoming 20 years, and finally provides outlines on how future research activities need to evolve.

# 1. Introduction

Polysaccharides are among the most abundant biological and renewable materials on our planet (Fig. 1). They are present in our everyday life in the form of energy storage, food, textiles, packaging, construction materials, and medicines. Polysaccharides will be central to the world of tomorrow as a transition to sustainable technologies is crucial for the future of humanity. Proper utilisation of polysaccharide resources has the potential to increase biodiversity, enhance food safety and sustainability, and decrease CO₂ emissions and pollution. Three main drivers strongly push the use of polysaccharides:

- the emergence of a bioeconomy that increases the contribution of biobased products

- the fact that these are polymers with various exceptional properties, opening routes for novel applications in all sectors of human activities such as materials science, nutrition, health, personal care, and energy

- the renewable character of polysaccharides, making them primary CO₂ neutral candidates for the global transformation to a more sustainable world.

To unfold the sustainable future of polysaccharides, a series of joint efforts in science, technology, education, and policy will be needed. The first step was already taken in 2007 when the European Polysaccharide Network of Excellence (EPNOE) Association was established with the support of the European Commission (EC). For 15 years, we have built a unique collaborative environment for scientists, institutions, and companies. Today, EPNOE is a vibrant organization with >50 institutions and companies from 20 countries. This unique international joint venture involving science, education and business inspired us to take the next step and create a visionary interdisciplinary document.

The EPNOE Research Roadmap presented herein is a joint collaborative effort of scientists from 13 European countries with the goal to build a unique vision of experts for the future of polysaccharide research and education in Europe and globally. The document has five strategic areas covering: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Fundamental Sciences (i.e., Chemistry, Biology & Physics), and (V) Skills & Education.

## 1.1. About the European Polysaccharide Network of Excellence (EPNOE)

EPNOE (www.epnoe.eu) was established in May 2005 as a Network of Excellence with funding from the EC under the FP6-NMP program Grant Agreement ID: 500375. This network instrument was designed to reduce fragmentation and strengthen competitiveness by assembling a critical mass of resources and expertise centered on various fields of science and technology (in our case polysaccharides). The ambition for this network was to continue to exist and grow on a long-term basis. To reach this goal, EPNOE was registered as a non-profit association in December 2007 and continued its activities after the end of EC funding in October 2009.

The initial focus of EPNOE was on promoting the use of polysaccharides as industry feedstock for the manufacturing of advanced, multifunctional materials. In March 2012, it received further funding from the EC for three years under the FP7-NMP program Grant Agreement ID: 290486 to expand activities towards health- and food-related materials and products as well as to increase industrial participation and innovation. EPNOE has continued after the end of the second period

of EC funding in February 2015 and now sustains its activities from membership fees. The network, which began with 16 academic and research institutions from 9 European countries, has grown to include >50 academic, research and industry institutions from all around the world.

## 1.2. Polysaccharides and biomass in the global perspective

Polysaccharides are defined as polymeric compounds consisting of a large number of monosaccharides that are linked through glycosidic bonds (IUPAC, 1997). They are frequently also referred to as *glycans*. As such, polysaccharide research can be considered as part or extension of *glycoscience*, a branch of research that focusses on carbohydrates (mono-, oligo-, and polysaccharides) as well as assemblies of carbohydrates with other compounds such as proteins (Barchi, 2021; National Research Council Committee on Assessing the Importance and Impact of Glycomics and Glycosciences, 2012). Polysaccharides are produced in large quantities by plants but also by microorganisms and animals and are consequently considered as highly valuable renewable resources. It is accepted that the amounts of oil, coal, and gas that we have been using as our major energy sources since the industrial revolution cannot be easily substituted. Their use, however, impacts society, climate, and politics. It causes pollution, and is regarded as non-sustainable at the current rate of consumption. Fossil carbon use is complemented by our growing global consumption of biomass for food, energy, and materials (Krausmann et al., 2013). This biomass is, in turn, essential for the preservation of biodiversity, land, water resources, and human health. In any case, fossil carbon deposits and biomass are an integral part of the global carbon cycle. Solutions to the current instability of the climate system, to pollution, biodiversity loss, and to rising global demands must include the right treatment of fossil-based and bioresources.

Biomass and polysaccharides are seen as attractive resources because they are almost exclusively based on a fascinating circular mode of production of photosynthetically captured carbon dioxide, with water as the reductant. Despite the essential importance of biomass, the limited per capita amounts that are available with current technology and land-use schemes also cause controversies among scientists, policymakers, and the public about the role of biomass in mitigating global challenges (Bar-On, Phillips, & Milo, 2018). Concerns are raised that an ever-increasing industrial use of biogenic raw materials, and a growing demand for food, will lead to reduced biodiversity, destruction of ecosystems, and harm the global climate. Fig. 2 summarizes different opinions on the role and use of biomass in more sustainable economic systems as related to climate actions (Strengers & Elzenga, 2020). Strategies for prudent use of biomass and polysaccharides are therefore of utmost importance, and no simple solution exists. Significant research efforts are needed to understand biosynthesis, structural variations, material properties, and the influence of biomass on health, ecology, and societies. Furthermore, new technologies might be necessary to increase or modify biomass production and how it is produced, used, recycled, and discarded.

One of the objectives of the EPNOE Research Roadmap was to assess the availability of biomass (with a focus on polysaccharides) according to the current scientific literature. Annual terrestrial global
What are Polysaccharides?

<figure><img src="image_4.png" /><figcaption>**Fig. 1.** Schematic overview about the origin of some examples of polysaccharides and their role as biomass.</figcaption></figure>
What are Polysaccharides?

<figure><img src="image_4.png" /><figcaption>**Fig. 1.** Schematic overview about the origin of some examples of polysaccharides and their role as biomass.</figcaption></figure>
photosynthetic net primary production of biomass was estimated to be around 60 gigatons (Gt) of carbon (Beer et al., 2010; Haberl et al., 2007). It is projected that 8–10 Gt of carbon (i.e., approximately 1 t per capita)<fnref n="2" /> are harvested each year by humanity in the form of biomass, with large regional disparities and increasing demands until 2050 (Zhou, Elshkaki, & Graedel, 2018). This has a significant impact on biodiversity, land, and other resource use. Compared to that, carbon emissions (in the form of CO₂) from fossil fuels and cement production were 9.5 Gt carbon in 2011, showing the magnitude of the disturbance of the natural biogenic carbon cycle by humans (Ciais et al., 2013). Although agriculture, forestry, and other land use are net CO₂ equivalent emitters (incl. CH₄, N₂O), it was assumed that the total global land area was a net sink of 11.2 ± 2.6 Gt CO₂ per year in the period 2007–2016 (Shukla et al., 2019). This demonstrates the enormous significance of biomass and polysaccharides in the context of the climate crisis.

According to recent studies, 1.466 Gt of dry matter biomass (ca. 3 t biomass per capita) was produced in 2013 by the land-based sectors in the European Union (EU, see Fig. 3), which back then encompassed 28 members states including the United Kingdom and Croatia. (Camia et al., 2018). The latest EU report (which excluded United Kingdom) describes a similar amount of approximately 1 Gt dry harvested biomass

for 2017 (Avitabile et al., 2023). Other sources stated a photosynthetic net primary production of 2.335 Gt carbon per year in the EU (excluding Croatia; ca. 4.6 t carbon per capita), with 36 % of it being used by humans (Plutzar et al., 2016). It needs to be considered that “Not all the biomass produced is harvested and used, part of it remains in the field to maintain the carbon sink and the other ecosystem services” and that “The biomass harvested and used in 2013 from the EU agricultural and forestry sectors was estimated at 805 Mt dry matter (578 Mt from agriculture, 227 Mt from forestry)”. Biomass standing stocks are substantially larger, for example: “The total above ground woody biomass of EU-28 forests was estimated at 18 600 Mt of dry matter…” (Camia et al., 2018). According to these numbers and assuming that the current amounts are sustainably regrown, biomass and polysaccharides are a plentiful albeit not inexhaustible resource at the European level.

As shown in Fig. 4, harvested biomass is mostly used for the feed and food sector (60 %), followed by bioenergy (19.1 %) and biobased materials (“biomaterials”; 18.8 %) with the latter including forest products such as paper and pulp (Camia et al., 2018). Depletion of the productive biomass stock of Earth has to be avoided to keep the ecosystems intact. Thus, the use of biomass for energy, materials, or food has to be considered when balancing the net primary biomass production.

The public debate on biomass

<figure><img src="image_5.png" /><figcaption>**Fig. 2.** Schematic representation of examples of public debates with different opinions about the role of biomass (BECCS: Bioenergy with Carbon Capture and Storage Technologies; IPCC: Intergovernmental Panel on Climate Change; WWF: World Wide Fund For Nature; VN: United Nations). Adapted from Strengers and Elzenga (2020) with permission.</figcaption></figure>

Considerate implementation of the biogenic carbon cycle and the use of polysaccharides must therefore be a part of any sustainable circular economy. It follows that there is tremendous demand for research and development to understand and increase the sustainability of biomass production and use. It should also be pointed out that assessments

<footnote n="2">² Based on a world population of about 8.0 billion people in the year 2020 according to World Bank data. https://data.worldbank.org/indicator/SP.POP.TOTL.</footnote>
photosynthetic net primary production of biomass was estimated to be around 60 gigatons (Gt) of carbon (Beer et al., 2010; Haberl et al., 2007). It is projected that 8–10 Gt of carbon (i.e., approximately 1 t per capita)<fnref n="2" /> are harvested each year by humanity in the form of biomass, with large regional disparities and increasing demands until 2050 (Zhou, Elshkaki, & Graedel, 2018). This has a significant impact on biodiversity, land, and other resource use. Compared to that, carbon emissions (in the form of CO₂) from fossil fuels and cement production were 9.5 Gt carbon in 2011, showing the magnitude of the disturbance of the natural biogenic carbon cycle by humans (Ciais et al., 2013). Although agriculture, forestry, and other land use are net CO₂ equivalent emitters (incl. CH₄, N₂O), it was assumed that the total global land area was a net sink of 11.2 ± 2.6 Gt CO₂ per year in the period 2007–2016 (Shukla et al., 2019). This demonstrates the enormous significance of biomass and polysaccharides in the context of the climate crisis.

According to recent studies, 1.466 Gt of dry matter biomass (ca. 3 t biomass per capita) was produced in 2013 by the land-based sectors in the European Union (EU, see Fig. 3), which back then encompassed 28 members states including the United Kingdom and Croatia. (Camia et al., 2018). The latest EU report (which excluded United Kingdom) describes a similar amount of approximately 1 Gt dry harvested biomass

for 2017 (Avitabile et al., 2023). Other sources stated a photosynthetic net primary production of 2.335 Gt carbon per year in the EU (excluding Croatia; ca. 4.6 t carbon per capita), with 36 % of it being used by humans (Plutzar et al., 2016). It needs to be considered that “Not all the biomass produced is harvested and used, part of it remains in the field to maintain the carbon sink and the other ecosystem services” and that “The biomass harvested and used in 2013 from the EU agricultural and forestry sectors was estimated at 805 Mt dry matter (578 Mt from agriculture, 227 Mt from forestry)”. Biomass standing stocks are substantially larger, for example: “The total above ground woody biomass of EU-28 forests was estimated at 18 600 Mt of dry matter…” (Camia et al., 2018). According to these numbers and assuming that the current amounts are sustainably regrown, biomass and polysaccharides are a plentiful albeit not inexhaustible resource at the European level.

As shown in Fig. 4, harvested biomass is mostly used for the feed and food sector (60 %), followed by bioenergy (19.1 %) and biobased materials (“biomaterials”; 18.8 %) with the latter including forest products such as paper and pulp (Camia et al., 2018). Depletion of the productive biomass stock of Earth has to be avoided to keep the ecosystems intact. Thus, the use of biomass for energy, materials, or food has to be considered when balancing the net primary biomass production.

The public debate on biomass

<figure><img src="image_5.png" /><figcaption>**Fig. 2.** Schematic representation of examples of public debates with different opinions about the role of biomass (BECCS: Bioenergy with Carbon Capture and Storage Technologies; IPCC: Intergovernmental Panel on Climate Change; WWF: World Wide Fund For Nature; VN: United Nations). Adapted from Strengers and Elzenga (2020) with permission.</figcaption></figure>

Considerate implementation of the biogenic carbon cycle and the use of polysaccharides must therefore be a part of any sustainable circular economy. It follows that there is tremendous demand for research and development to understand and increase the sustainability of biomass production and use. It should also be pointed out that assessments

<footnote n="2">² Based on a world population of about 8.0 billion people in the year 2020 according to World Bank data. https://data.worldbank.org/indicator/SP.POP.TOTL.</footnote>
<figure><img src="image_6.png" /><figcaption>**Fig. 3.** Overview of the annual biomass production (in megatonnes (Mt) dry matter) from land-based sectors (excluding pastures) within the European Union (10-year average 2006–2015).

Adapted from Camia et al. (2018) with permission.</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>**Fig. 4.** Distribution of biomass uses in the European Union.

Adapted from Camia et al. (2018) with permission.</figcaption></figure>

regarding to which extent biomass production and use can be called *sustainable* and with which technology biomass can substitute fossil carbon cannot be answered easily up to now. Moreover, gaps, uncertainties, and future developments for different biomass sources must be considered as described in the following quotes from literature (Camia et al., 2018):

- Biomass from agriculture: "However, it is important to note that food and feed uses are by far the main type of utilisation of agricultural

biomass (in quantity). Being currently captured, the overall picture of agricultural biomass flows is already informative. Missing uses represent a very small fraction of agricultural biomass uses when measured in quantity, although they may represent a larger fraction of biomass uses when measured in economic value."

- Biomass from forestry: "As already hinted at, there are numerous uncertainties in the data. The most critical concerns harvest levels and removals of woody biomass from EU forests. Another major
<figure><img src="image_6.png" /><figcaption>**Fig. 3.** Overview of the annual biomass production (in megatonnes (Mt) dry matter) from land-based sectors (excluding pastures) within the European Union (10-year average 2006–2015).

Adapted from Camia et al. (2018) with permission.</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>**Fig. 4.** Distribution of biomass uses in the European Union.

Adapted from Camia et al. (2018) with permission.</figcaption></figure>

regarding to which extent biomass production and use can be called *sustainable* and with which technology biomass can substitute fossil carbon cannot be answered easily up to now. Moreover, gaps, uncertainties, and future developments for different biomass sources must be considered as described in the following quotes from literature (Camia et al., 2018):

- Biomass from agriculture: "However, it is important to note that food and feed uses are by far the main type of utilisation of agricultural

biomass (in quantity). Being currently captured, the overall picture of agricultural biomass flows is already informative. Missing uses represent a very small fraction of agricultural biomass uses when measured in quantity, although they may represent a larger fraction of biomass uses when measured in economic value."

- Biomass from forestry: "As already hinted at, there are numerous uncertainties in the data. The most critical concerns harvest levels and removals of woody biomass from EU forests. Another major
uncertainty relates to energy uses, values are often underestimated or at times outright missing.”

- Biomass from fisheries and aquaculture: “With globalisation, international trade of seafood products has become very complex and seafood products can come from different sources, having often passed through various stations in the production and supply chain .... This poses many challenges to the already difficult monitoring activities in the whole fisheries sector.” and “Potential environmental impacts of fisheries and aquaculture need to be assessed.”

- Biomass from algae: “The FAO [comment: the Food and Agriculture Organization of the United Nations] and Eurostat databases include very fragmented information regarding the uses, economic value and market flows of algal biomass at the European level. This results from the incomplete reporting by member states and the confidentiality issues imposed by the business sector. Additionally, no information is available on the commercial use of algal biomass at national level. This limits the realistic assessment of the trade flows, for some species and countries with high internal market consumption of the biomass production.” and “Resulting from market demands, global seaweed biomass production has increased exponentially in the last decade.”

In addition to the mentioned facts, different scenarios should be considered, and sustainable biomass supply estimates need to be compared with models that project the demand and supply in 2040 and beyond.

## 2. The EPNOE Research Roadmap 2040

### 2.1. Concrete outreach to policymakers and key messages

The EPNOE Research Roadmap has strong and synergistic links to EU strategies and objectives, including the EU Bioeconomy Strategy, EU Green Deal, EU Missions, Horizon Europe Clusters, and EU Industrial Strategy. Polysaccharides are CO₂ neutral with additional advantages of acting as carbon storage, holding well-established processability at an industrial scale, and easy functionalisation to meet current and future challenges in commodity and speciality areas involving materials, energy, food, and health. These assets are of extremely high relevance when it comes to achieving the five goals of the EU Bioeconomy Strategy and climate neutrality of the EU Green Deal by 2050. Additionally, the advances in polysaccharide science and technology will open new frontiers required to meet the five EU Missions, to create new knowledge and innovation to successfully address opportunities in Horizon Europe Clusters and EU Industrial Strategy.

The following key messages are of outmost importance to fully understand the importance that polysaccharides will play in the future:

- Polysaccharides are essential to life, abundant, and tailored by nature to act as carbon storage and functionality carriers for essential areas of human and planet health and well-being. These features have been overlooked in National and European strategies.

- Sustainability and circularity require more emphasis on both the beginning and end-of-life scenarios of polysaccharide products. The end-of-life properties need to be designed at an early stage of research. Recyclability, biodegradability, reusability and, after cascading use, conversion to energy must be rationally designed and engineered from conception to production and include consumption and post-use.

- Polysaccharide innovations should aim for long-service life products to ensure and enhance carbon storage and functionality to replace fossil-based material solutions.

- Safety through the design of polysaccharide materials should be implemented in research and innovation policies to ensure that future solutions have minimal toxicity, are healthy for humans and the planet, and are economically, environmentally, and socially viable.

- Biomedical applications of polysaccharides should contemplate the manufacture and quality standards and scale of polysaccharide biomaterials from the research and development standpoint, their practicality, off-shelf use, cost-effectiveness, and business model. Moreover, the preparation of harmonised regulatory frameworks to accelerate the introduction of polysaccharide-based biomaterials into clinical practice in collaboration among academics, clinicians, companies, and regulatory authorities should be supported by policymakers.

- We suggest that consumers and citizens must be more engaged in polysaccharide-based solutions and informed about the advantages of polysaccharides and their benefits for the health of the planet, humans, and society. Development of labels, digital platforms, and tools to guide and support consumers and citizens with science-based knowledge is suggested.

- Cross-disciplinary collaborations need to be further supported with different stakeholders, including universities, research institutes, industry, non-governmental organisations, society, and all relevant players. Investments in fundamental science, in new analytical technologies to support the understanding of structure-property-relationships, in scaling up of research to support commercialisation, and in creation of new critical mass in circularity and replacement of plastics are required.

- Education and permanent training of polysaccharide scientists and technologists are essential to improve sustainability, circularity, and rational design of future processes and products. Education and training activities involving different stakeholders, disciplines, and societal actors need support at National and European levels. Creation workshops, training schools, joint degrees, policy briefs, innovation workshops with combined inputs of academics, small enterprises, industry, and policymakers are examples of activities to be further supported.

### 2.2. General outline and structure of the roadmap

The strategic EPNOE Research Roadmap covers different relevant areas (Fig. 5). The following document was prepared considering the broadness of the topic and the gaps and uncertainties of available literature and it is based on the knowledge and skills of experienced researchers working in the respective areas. The major areas that will impact polysaccharide-related research in the future are covered: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology, & Physics, and (V) Skills & Education. Each individual paragraph will provide a discussion on (i) the current challenges, (ii) the expected achievements and developments in the coming 20 years, and (iii) the required research activities needed to address the most important scientific and societal questions to be answered. The main goal of the EPNOE Research Roadmap is to arrive at solutions for a sustainable use of biomass resources while enhancing biodiversity. The strategic choice of research activities in polysaccharides as a part of a very diverse biomass is very important and essential to achieve a sustainable development of our society.

## 3. Materials sciences & engineering

To date, most plastic man-made materials and their composites are made from fossil-based polymers. Their ability to be moulded with the desired shape, their durability, light weight, and inexpensive production have made plastics the most employed man-made material so far. In the context of a more sustainable planet and a more efficient circular economy, polysaccharides are very well-positioned to transition from fossil-based to biobased materials with equal or improved performances. The share of biobased materials in commodities and consumer and speciality products is expected to increase steadily in the following
uncertainty relates to energy uses, values are often underestimated or at times outright missing.”

- Biomass from fisheries and aquaculture: “With globalisation, international trade of seafood products has become very complex and seafood products can come from different sources, having often passed through various stations in the production and supply chain .... This poses many challenges to the already difficult monitoring activities in the whole fisheries sector.” and “Potential environmental impacts of fisheries and aquaculture need to be assessed.”

- Biomass from algae: “The FAO [comment: the Food and Agriculture Organization of the United Nations] and Eurostat databases include very fragmented information regarding the uses, economic value and market flows of algal biomass at the European level. This results from the incomplete reporting by member states and the confidentiality issues imposed by the business sector. Additionally, no information is available on the commercial use of algal biomass at national level. This limits the realistic assessment of the trade flows, for some species and countries with high internal market consumption of the biomass production.” and “Resulting from market demands, global seaweed biomass production has increased exponentially in the last decade.”

In addition to the mentioned facts, different scenarios should be considered, and sustainable biomass supply estimates need to be compared with models that project the demand and supply in 2040 and beyond.

## 2. The EPNOE Research Roadmap 2040

### 2.1. Concrete outreach to policymakers and key messages

The EPNOE Research Roadmap has strong and synergistic links to EU strategies and objectives, including the EU Bioeconomy Strategy, EU Green Deal, EU Missions, Horizon Europe Clusters, and EU Industrial Strategy. Polysaccharides are CO₂ neutral with additional advantages of acting as carbon storage, holding well-established processability at an industrial scale, and easy functionalisation to meet current and future challenges in commodity and speciality areas involving materials, energy, food, and health. These assets are of extremely high relevance when it comes to achieving the five goals of the EU Bioeconomy Strategy and climate neutrality of the EU Green Deal by 2050. Additionally, the advances in polysaccharide science and technology will open new frontiers required to meet the five EU Missions, to create new knowledge and innovation to successfully address opportunities in Horizon Europe Clusters and EU Industrial Strategy.

The following key messages are of utmost importance to fully understand the importance that polysaccharides will play in the future:

- Polysaccharides are essential to life, abundant, and tailored by nature to act as carbon storage and functionality carriers for essential areas of human and planet health and well-being. These features have been overlooked in National and European strategies.

- Sustainability and circularity require more emphasis on both the beginning and end-of-life scenarios of polysaccharide products. The end-of-life properties need to be designed at an early stage of research. Recyclability, biodegradability, reusability and, after cascading use, conversion to energy must be rationally designed and engineered from conception to production and include consumption and post-use.

- Polysaccharide innovations should aim for long-service life products to ensure and enhance carbon storage and functionality to replace fossil-based material solutions.

- Safety through the design of polysaccharide materials should be implemented in research and innovation policies to ensure that future solutions have minimal toxicity, are healthy for humans and the planet, and are economically, environmentally, and socially viable.

- Biomedical applications of polysaccharides should contemplate the manufacture and quality standards and scale of polysaccharide biomaterials from the research and development standpoint, their practicality, off-shelf use, cost-effectiveness, and business model. Moreover, the preparation of harmonised regulatory frameworks to accelerate the introduction of polysaccharide-based biomaterials into clinical practice in collaboration among academics, clinicians, companies, and regulatory authorities should be supported by policymakers.

- We suggest that consumers and citizens must be more engaged in polysaccharide-based solutions and informed about the advantages of polysaccharides and their benefits for the health of the planet, humans, and society. Development of labels, digital platforms, and tools to guide and support consumers and citizens with science-based knowledge is suggested.

- Cross-disciplinary collaborations need to be further supported with different stakeholders, including universities, research institutes, industry, non-governmental organisations, society, and all relevant players. Investments in fundamental science, in new analytical technologies to support the understanding of structure-property-relationships, in scaling up of research to support commercialisation, and in creation of new critical mass in circularity and replacement of plastics are required.

- Education and permanent training of polysaccharide scientists and technologists are essential to improve sustainability, circularity, and rational design of future processes and products. Education and training activities involving different stakeholders, disciplines, and societal actors need support at National and European levels. Creation workshops, training schools, joint degrees, policy briefs, innovation workshops with combined inputs of academics, small enterprises, industry, and policymakers are examples of activities to be further supported.

### 2.2. General outline and structure of the roadmap

The strategic EPNOE Research Roadmap covers different relevant areas (Fig. 5). The following document was prepared considering the broadness of the topic and the gaps and uncertainties of available literature and it is based on the knowledge and skills of experienced researchers working in the respective areas. The major areas that will impact polysaccharide-related research in the future are covered: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology, & Physics, and (V) Skills & Education. Each individual paragraph will provide a discussion on (i) the current challenges, (ii) the expected achievements and developments in the coming 20 years, and (iii) the required research activities needed to address the most important scientific and societal questions to be answered. The main goal of the EPNOE Research Roadmap is to arrive at solutions for a sustainable use of biomass resources while enhancing biodiversity. The strategic choice of research activities in polysaccharides as a part of a very diverse biomass is very important and essential to achieve a sustainable development of our society.

## 3. Materials sciences & engineering

To date, most plastic man-made materials and their composites are made from fossil-based polymers. Their ability to be moulded with the desired shape, their durability, light weight, and inexpensive production have made plastics the most employed man-made material so far. In the context of a more sustainable planet and a more efficient circular economy, polysaccharides are very well-positioned to transition from fossil-based to biobased materials with equal or improved performances. The share of biobased materials in commodities and consumer and speciality products is expected to increase steadily in the following
Research Road Map

<figure><img src="image_8.png" /><figcaption>Fig. 5. Overall scheme of the EPNOE Research Roadmap with the key strategic scientific areas.</figcaption></figure>

years. Below are some selected prospects for the next 20 years in terms of new tailor-made polysaccharide-based materials, their emerging applications and novel processing approaches.

(i) The next generations of polysaccharide-based materials will complement currently employed semi-synthetic materials and find inspiration in nature in the attempt to mimic both form and function:

- in polysaccharide derivatives that replicate bioinspired functionalities and low degrees of substitution as opposed to traditional polysaccharide esters and ethers used as thermoplastics and coatings

- in structural colouring in optoelectronic and photonic devices

- in bioimplants, biosensors, and biointergrateable electronics such as electronic eye and skin, wearable and implantable electronics as soft and deformable mechanical supports

- in bioactive polysaccharides that can generate novel materials

(ii) The use of functional composites from sustainable and renewable resources will be pivotal in our future industrial practices. Polysaccharides can be used both as a continuous or a dispersed phase:

- polysaccharide matrices with a magnetic, plasmonic, or conductive dispersed phase

- polysaccharide-protein interpenetrated networks for stiff and tough hydrogels

- transparent wood for touch-sensitive tactile panels

- biodegradable materials, in particular for packaging applications

(iii) Processing of polysaccharides must be economical and environmentally competitive:

- more efficient biorefinery approaches should be developed for extraction, purification, and shaping of polysaccharides

- methods already well-established in other areas but new in the context of processing of polysaccharides should be explored

- new sources of polysaccharides, such as microalgae, hemicelluloses, or exopolysaccharides (e.g., yeast-based, recombinant cell factories) have to be considered

(iv) The current increased digitalisation and continuous development in the area of *internet-of-things* must be combined with sustainable practices. Polysaccharides will thus be strategic components for energy storage and harvesting, replacing synthetic polymers:

- in batteries as binders, separators, and electrolytes

- in supercapacitors as biobased carbons, binders, dispersing agents, and permeable separators

- for energy harvesting, such as cellulose-based dielectric materials in triboelectric nanogenerators

- in solar cells, photonic and optoelectronic applications

- as flexible substrates in wearable electronics

Although polysaccharides might appear as an inexhaustible resource, it is important to identify and study the available feedstock in relation to the techno-economical perspective for each specific product and application to enable a sustainable production. Interdisciplinarity combined with the sustainable and circular economy should be a general approach to advance.

### 3.1. Next generation of polysaccharide-based materials and functional composites

#### 3.1.1. Current challenges

Most fossil-based synthetic or semi-synthetic polymers are easy to shape, lightweight, and have a long-lasting exploitation duration. Their inexpensive production has made them one of the most employed materials during the past century, with a production of over 400 million tons in 2020, about 50 % more than in the previous decade. In the quest
Research Road Map

<figure><img src="image_8.png" /><figcaption>Fig. 5. Overall scheme of the EPNOE Research Roadmap with the key strategic scientific areas.</figcaption></figure>

years. Below are some selected prospects for the next 20 years in terms of new tailor-made polysaccharide-based materials, their emerging applications and novel processing approaches.

(i) The next generations of polysaccharide-based materials will complement currently employed semi-synthetic materials and find inspiration in nature in the attempt to mimic both form and function:

- in polysaccharide derivatives that replicate bioinspired functionalities and low degrees of substitution as opposed to traditional polysaccharide esters and ethers used as thermoplastics and coatings

- in structural colouring in optoelectronic and photonic devices

- in bioimplants, biosensors, and biointergrateable electronics such as electronic eye and skin, wearable and implantable electronics as soft and deformable mechanical supports

- in bioactive polysaccharides that can generate novel materials

(ii) The use of functional composites from sustainable and renewable resources will be pivotal in our future industrial practices. Polysaccharides can be used both as a continuous or a dispersed phase:

- polysaccharide matrices with a magnetic, plasmonic, or conductive dispersed phase

- polysaccharide-protein interpenetrated networks for stiff and tough hydrogels

- transparent wood for touch-sensitive tactile panels

- biodegradable materials, in particular for packaging applications

(iii) Processing of polysaccharides must be economical and environmentally competitive:

- more efficient biorefinery approaches should be developed for extraction, purification, and shaping of polysaccharides

- methods already well-established in other areas but new in the context of processing of polysaccharides should be explored

- new sources of polysaccharides, such as microalgae, hemicelluloses, or exopolysaccharides (e.g., yeast-based, recombinant cell factories) have to be considered

(iv) The current increased digitalisation and continuous development in the area of internet-of-things must be combined with sustainable practices. Polysaccharides will thus be strategic components for energy storage and harvesting, replacing synthetic polymers:

- in batteries as binders, separators, and electrolytes

- in supercapacitors as biobased carbons, binders, dispersing agents, and permeable separators

- for energy harvesting, such as cellulose-based dielectric materials in triboelectric nanogenerators

- in solar cells, photonic and optoelectronic applications

- as flexible substrates in wearable electronics

Although polysaccharides might appear as an inexhaustible resource, it is important to identify and study the available feedstock in relation to the techno-economical perspective for each specific product and application to enable a sustainable production. Interdisciplinarity combined with the sustainable and circular economy should be a general approach to advance.

### 3.1. Next generation of polysaccharide-based materials and functional composites

#### 3.1.1. Current challenges

Most fossil-based synthetic or semi-synthetic polymers are easy to shape, lightweight, and have a long-lasting exploitation duration. Their inexpensive production has made them one of the most employed materials during the past century, with a production of over 400 million tons in 2020, about 50 % more than in the previous decade. In the quest
to transition from fossil-based to biobased materials with equal or
improved performances, polysaccharides are well-positioned. To that
end, polysaccharide-based materials with a higher degree of complexity
and added value are gathering deserved growing scientific interest,
aspiring to secure a place in high-tech sectors by demonstrating
improved performance and functional versatility. However, poly-
saccharide alternatives for the replacement of oil-based plastics still
have many challenges. Currently, the latter can be produced easily and
cascaded down to energy recovery, while comparable technologies for
polysaccharide-based solutions are still under development. Other
relevant challenges are: "How much land will be needed?" and "What
will be the environmental cost to produce the required biomass as raw
material for polysaccharide-based plastics to replace oil-based ones?"

**3.1.2. Expected achievements and developments in the next 20 years**

Next generations of engineered polysaccharide-based materials will continue to be inspired by the animal-, plant-, and mineral kingdoms. The vision is to use natural models to guide material scientists to smartly select the right combination of polysaccharides and adequately process them to manufacture increasingly reliable natural replicates that could mimic both form and function (Heise et al., 2021). As an example, the panoply of optical phenomena found in nature as a result of complex light-harnessing and light-matter interaction will find replicates in nanostructured polysaccharides, i.e., materials with structural colour holograms, light waveguiding and control of transparency, haze or scattering centres (Droguet et al., 2022). Such materials will then be integrated into optoelectronics and photonic devices, and even the material will be designed to serve as a device. Bioinspiration, taken from skeletal-muscle tissues with highly oriented and densely packed myo-fibres to transmit forces and contract muscles or from the amazing regeneration potential of foetal skin involving the formation of actin cables at wound edges, will stimulate the creation of new polysaccharide-based materials that are mechanically compliant, stimuli-responsive, self-healable, or adhesive in wet bioenvironments (Blacklow et al., 2019).

Here, the expectations are that polysaccharides can play a key role in the future of bioimplants, biosensors, and biointegratable electronics (such as electronic eyes and wearable and implantable electronics) as soft and deformable mechanical supports that can efficiently dissipate the induced stresses from the body movement. In addition, wood, cellulose fibres, and other polysaccharides have tremendous potential for the fabrication of highly engineered materials and as templates to guide the fabrication of other materials (Li et al., 2021). Their hierarchical porous structure or the nanoscale size of the fibres will serve on a variety of templating mechanisms to obtain biomorphic structures. Finally, the field of engineered living materials to biosynthesise novel materials using cells is a futuristic vision to employ bioactive polysaccharides (Gilbert et al., 2021).

The increased use of composite biobased materials from sustainable and renewable resources is pivotal for the next generation of industrial practices (Mohanty, Vivekanandhan, Pin, & Misra, 2018). The polysaccharide component can act as the primary phase using a non-polysaccharide secondary component to endow functionality such as magnetic, plasmonic, electric, or ionic conductivity (Roig-Sanchez et al., 2019). Alternatively, the composite can be entirely manufactured with biopolymer components, i.e., by using polysaccharides and proteins conjoined networks strategies in the quest for stiff and tough hydrogels (Xu et al., 2019), or the use of nanocelluloses to improve gas barrier and sub-optimal mechanical characteristics of starch used in the food industry. Besides, synthetic polymers will be reinforced by wood or nanocelluloses (which is already produced on a large scale) and will play a role in fine-tuning the rheology of the polymer, impacting the capacity for 3D printing or UV-curing them. Engineering wood for technological applications deserves specific mention. A unique structure and anisotropy provide wood with opportunities beyond its structural function. For instance, after delignification, transparent wood can be obtained,

resulting in a lightweight material with load-bearing properties that can
encompass lighting features via the inclusion of luminescent particles
(Montanari, Ogawa, Olsén, & Berglund, 2021). Besides construction
industries, the automotive sector is highly interested in integrating
electronics into touch-sensitive wood tactile dashboards.

The development of biodegradable packaging materials, particularly those based on polysaccharides, presents a promising opportunity for addressing environmental concerns associated with traditional packaging. For example, paper-based packaging based on lignocellulosic fibres already share 25 % of the packaging market and is expected to grow annually at the level of 4.7 % during 2023–2028.<fnref n="3" /> In addition to their natural biodegradability, several polysaccharides such as cellulose and starch possess excellent film-forming properties (Cheng et al., 2021). Blending of polysaccharides and/or making composite materials (e.g., with starch or nanocellulose) allows the fabrication of intelligent packaging with tuneable mechanical-, barrier-, and/or antimicrobial properties (Wu, Misra, & Mohanty, 2021; Zhong, Godwin, Jin, & Xiao, 2020). Smart packaging solutions should go beyond traditional roles, offering real-time data and interactive features that enhance product safety, quality, and consumer engagement.

**3.1.3. Required research activities**

From a materials science viewpoint, to fully display polysaccharides'
opportunities in materials and engineering, research activities will be
necessary for a wide span of different areas. The use of advanced char-
acterisation tools as well as computational and machine learning ap-
proaches to inform on potential new designs and assist in the
understanding of the structure-property-relationships of the novel
engineered polysaccharides will be necessary.

Other required research activities will be more specific to the type of material being developed and its final application. For instance, although, at present, 100 % polysaccharide-based materials have a sizeable market share in sustainable and biodegradable packaging, more research efforts are needed to increase their durability, lower their costs, and tune their properties towards specific applications (e.g., food industry). In the context of functional nanocomposites, significant challenges are in the development of high-strength nanocomposites with exquisite control and reproducibility of the nanoparticles' properties, their loading fraction and topographic distribution within the polysaccharide matrix. In addition, large-scale fabrication processes and success stories of their commercial use will have to be ensured.

Concerning biomaterials, meaningful research activities could focus
on the control of self-degradation or trigger-able detachment of bio-
integratable implants for minimally invasive surgeries, the decrease of
cross-linking reagents and decrease or avoidance of non-polysaccharide
components in hybrid nanocomposites, as well as in the finer tuning and
modelling of material responsiveness to various stimuli or the imple-
mentation of a self-regulative function considering the continuous
diffusion between the tissue and the biomaterial. To impact the light/
polysaccharides interactions, a precise control of transparency, degree
of haze, modulation of structural colours, and precise waveguiding will
be important for optoelectronic applications. Achieving the formation of
holograms using polysaccharide building blocks will certainly be a
major accomplishment in the field.

In the developing field of engineered living materials, the biosyn-
thesis of polysaccharides with predictable and complex 3D architectures
and functions across multiple scales in a continuous production loop will
be a major research topic in the coming years. Finally, the use of poly-
saccharides in microfluidics for single-use recyclable devices is rapidly
growing, while their use in transient electronics, an emerging class of
electronics programmed to dissolve within a period of time without

<footnote n="3">³ Paper Packaging Market Size & Share Analysis - Growth Trends & Forecasts (2023–2028); source: https://www.mordorintelligence.com/industry-reports/paper-packaging-market.</footnote>
to transition from fossil-based to biobased materials with equal or
improved performances, polysaccharides are well-positioned. To that
end, polysaccharide-based materials with a higher degree of complexity
and added value are gathering deserved growing scientific interest,
aspiring to secure a place in high-tech sectors by demonstrating
improved performance and functional versatility. However, poly-
saccharide alternatives for the replacement of oil-based plastics still
have many challenges. Currently, the latter can be produced easily and
cascaded down to energy recovery, while comparable technologies for
polysaccharide-based solutions are still under development. Other
relevant challenges are: "How much land will be needed?" and "What
will be the environmental cost to produce the required biomass as raw
material for polysaccharide-based plastics to replace oil-based ones?"

**3.1.2. Expected achievements and developments in the next 20 years**

Next generations of engineered polysaccharide-based materials will continue to be inspired by the animal-, plant-, and mineral kingdoms. The vision is to use natural models to guide material scientists to smartly select the right combination of polysaccharides and adequately process them to manufacture increasingly reliable natural replicates that could mimic both form and function (Heise et al., 2021). As an example, the panoply of optical phenomena found in nature as a result of complex light-harnessing and light-matter interaction will find replicates in nanostructured polysaccharides, i.e., materials with structural colour holograms, light waveguiding and control of transparency, haze or scattering centres (Droguet et al., 2022). Such materials will then be integrated into optoelectronics and photonic devices, and even the material will be designed to serve as a device. Bioinspiration, taken from skeletal-muscle tissues with highly oriented and densely packed myo-fibres to transmit forces and contract muscles or from the amazing regeneration potential of foetal skin involving the formation of actin cables at wound edges, will stimulate the creation of new polysaccharide-based materials that are mechanically compliant, stimuli-responsive, self-healable, or adhesive in wet bioenvironments (Blacklow et al., 2019).

Here, the expectations are that polysaccharides can play a key role in the future of bioimplants, biosensors, and biointegratable electronics (such as electronic eyes and wearable and implantable electronics) as soft and deformable mechanical supports that can efficiently dissipate the induced stresses from the body movement. In addition, wood, cellulose fibres, and other polysaccharides have tremendous potential for the fabrication of highly engineered materials and as templates to guide the fabrication of other materials (Li et al., 2021). Their hierarchical porous structure or the nanoscale size of the fibres will serve on a variety of templating mechanisms to obtain biomorphic structures. Finally, the field of engineered living materials to biosynthesise novel materials using cells is a futuristic vision to employ bioactive polysaccharides (Gilbert et al., 2021).

The increased use of composite biobased materials from sustainable and renewable resources is pivotal for the next generation of industrial practices (Mohanty, Vivekanandhan, Pin, & Misra, 2018). The polysaccharide component can act as the primary phase using a non-polysaccharide secondary component to endow functionality such as magnetic, plasmonic, electric, or ionic conductivity (Roig-Sanchez et al., 2019). Alternatively, the composite can be entirely manufactured with biopolymer components, i.e., by using polysaccharides and proteins conjoined networks strategies in the quest for stiff and tough hydrogels (Xu et al., 2019), or the use of nanocelluloses to improve gas barrier and sub-optimal mechanical characteristics of starch used in the food industry. Besides, synthetic polymers will be reinforced by wood or nanocelluloses (which is already produced on a large scale) and will play a role in fine-tuning the rheology of the polymer, impacting the capacity for 3D printing or UV-curing them. Engineering wood for technological applications deserves specific mention. A unique structure and anisotropy provide wood with opportunities beyond its structural function. For instance, after delignification, transparent wood can be obtained,

resulting in a lightweight material with load-bearing properties that can
encompass lighting features via the inclusion of luminescent particles
(Montanari, Ogawa, Olsén, & Berglund, 2021). Besides construction
industries, the automotive sector is highly interested in integrating
electronics into touch-sensitive wood tactile dashboards.

The development of biodegradable packaging materials, particularly those based on polysaccharides, presents a promising opportunity for addressing environmental concerns associated with traditional packaging. For example, paper-based packaging based on lignocellulosic fibres already share 25 % of the packaging market and is expected to grow annually at the level of 4.7 % during 2023–2028.<fnref n="3" /> In addition to their natural biodegradability, several polysaccharides such as cellulose and starch possess excellent film-forming properties (Cheng et al., 2021). Blending of polysaccharides and/or making composite materials (e.g., with starch or nanocellulose) allows the fabrication of intelligent packaging with tuneable mechanical-, barrier-, and/or antimicrobial properties (Wu, Misra, & Mohanty, 2021; Zhong, Godwin, Jin, & Xiao, 2020). Smart packaging solutions should go beyond traditional roles, offering real-time data and interactive features that enhance product safety, quality, and consumer engagement.

**3.1.3. Required research activities**

From a materials science viewpoint, to fully display polysaccharides'
opportunities in materials and engineering, research activities will be
necessary for a wide span of different areas. The use of advanced char-
acterisation tools as well as computational and machine learning ap-
proaches to inform on potential new designs and assist in the
understanding of the structure-property-relationships of the novel
engineered polysaccharides will be necessary.

Other required research activities will be more specific to the type of material being developed and its final application. For instance, although, at present, 100 % polysaccharide-based materials have a sizeable market share in sustainable and biodegradable packaging, more research efforts are needed to increase their durability, lower their costs, and tune their properties towards specific applications (e.g., food industry). In the context of functional nanocomposites, significant challenges are in the development of high-strength nanocomposites with exquisite control and reproducibility of the nanoparticles' properties, their loading fraction and topographic distribution within the polysaccharide matrix. In addition, large-scale fabrication processes and success stories of their commercial use will have to be ensured.

Concerning biomaterials, meaningful research activities could focus
on the control of self-degradation or trigger-able detachment of bio-
integratable implants for minimally invasive surgeries, the decrease of
cross-linking reagents and decrease or avoidance of non-polysaccharide
components in hybrid nanocomposites, as well as in the finer tuning and
modelling of material responsiveness to various stimuli or the imple-
mentation of a self-regulative function considering the continuous
diffusion between the tissue and the biomaterial. To impact the light/
polysaccharides interactions, a precise control of transparency, degree
of haze, modulation of structural colours, and precise waveguiding will
be important for optoelectronic applications. Achieving the formation of
holograms using polysaccharide building blocks will certainly be a
major accomplishment in the field.

In the developing field of engineered living materials, the biosyn-
thesis of polysaccharides with predictable and complex 3D architectures
and functions across multiple scales in a continuous production loop will
be a major research topic in the coming years. Finally, the use of poly-
saccharides in microfluidics for single-use recyclable devices is rapidly
growing, while their use in transient electronics, an emerging class of
electronics programmed to dissolve within a period of time without

<footnote n="3">³ Paper Packaging Market Size & Share Analysis - Growth Trends & Forecasts (2023–2028); source: https://www.mordorintelligence.com/industry-reports/paper-packaging-market.</footnote>
generating harmful by-products, is a stimulating research field expected to capture enormous interest in the coming years.

## 3.2. Processing of polysaccharides

### 3.2.1. Current challenges

Processing is defined as transforming raw materials into finished products of certain shapes and properties. Polysaccharides are polymers; however, not all processing approaches developed for synthetic polymers can be and are currently used. Most polysaccharides are not thermoplastic. The difficulty in shaping polysaccharides results, in part, from strong intra- and intermolecular interactions between macromolecules, which prevent chains' mobility needed for melt processing.

The majority of natural polysaccharides are thus processed via solubilisation. Depending on the application, many of them remain in a dissolved state: for example, pectin, alginate, and carrageenans are used as viscosity modifiers, gelling agents, and gels in food, cosmetics, and pharmaceutics. These polymers can also be shaped into films by casting solutions followed by solvent evaporation. Cellulose dissolved via the viscose process is spun into fibres for textile and non-woven applications or cast into films. Much progress has been made in finding cellulose dissolution options (Lyocell process, dissolution in ionic liquids) as an alternative to the viscose process, which is very polluting (Liebert, 2010). Chitin is very difficult to dissolve and it is thus transformed into chitosan, which can then be dissolved in acidic aqueous media and processed into fibres or films (Pillai, Paul, & Sharma, 2009). To use starch for food applications and for packaging, it is usually prepared as an aqueous paste, which is the result of a gelatinisation process (Wang & Copeland, 2013). Foams and films are made from thermoplastic starch for packaging and agricultural applications.

The above concerns the processing of neat polysaccharides. However, except in very rare cases, polysaccharides exist in nature as mixtures with various other substances of low or high molecular weight. The classical example is natural fibres which are complex composite materials of polysaccharides (cellulose and hemicelluloses) and non-polysaccharide polymers (lignin) organised in a sort of an interpenetrated network. Alginate or carrageenan in seaweeds coexist with cellulose, proteins, minerals, and lipids. Chitin in crustacean shells or in mushrooms is mixed with minerals and proteins. Extraction of polysaccharides from these natural composites is thus needed for their further processing. The extraction methods are well known, but optimisation is still needed to improve efficiency and decrease the use of harmful chemicals.

Polysaccharides can also be processed in suspension after extraction or disassembly of native polysaccharide particles and fibrils from biomass. This process involves multiple steps, and it is resource and energy intensive. Finally, chemically modified polysaccharides, so-called polysaccharide derivatives, make a class of polymers with some of them being thermoplastics or easy to dissolve in water (e.g., cellulose ethers). Several cellulose esters can be melt processed in the same way as synthetic polymers. They can also be dissolved to cast films and spin fibres and non-wovens. Starch derivatives are processed and used in a similar way as cellulose derivatives.

Microorganisms as cell factories play several roles in the context of polysaccharide chemistry and processing (Tiwari, Sasmal, Kataria, & Devi, 2020). Many bacteria produce exopolysaccharides, which are industrially quite important, such as xanthan. Other polysaccharides produced by microbes (such as hyaluronic acid, kefiran, or gellan) are currently used for biomedical applications (Mohd Nadzir, Nurhayati, Idris, & Nguyen, 2021). Bacterial cellulose is of special importance for biomedical applications due to its high purity. Its properties can be modified by varying the cell factory or the production conditions, opening new fields of cellulose chemistry, processing, and applications. Levans are of increasing interest; they are fructans of bacterial origin with quite interesting properties. Microorganisms are also producing polysaccharide-modifying enzymes and can thus be used as whole cell

catalysts for polysaccharide modifications. As such, microbial catalysts open new opportunities for polysaccharide chemistry and processing.

### 3.2.2. Expected achievements and developments in the next 20 years

Biorefinery approaches are and will be in the focus of polysaccharide processing: their extraction, purification and shaping. New processing methods (in the context of polysaccharides) have begun to be applied. The management of resources must be sustainable, and their use must be efficient, with minimum waste, and environmentally friendly. This requires reconsideration of the traditional ways of polysaccharide processing, which opens prospects for innovation. For example, new eco-friendly solvents and their recovery are a focus of research. This concerns cellulose dissolution and shaping, which is an old but still a very relevant problem. Some ionic liquids have been demonstrated to be powerful cellulose solvents, and the properties of fibres spun from these solvents compete with those obtained from viscose and Lyocell processes (Hummel et al., 2016). Still, ionic liquids are expensive, and to date, their recovery is complicated. There is a revival of interest in aqueous hydroxide-based solvents to be used for cellulose shaping (Budtova & Navard, 2016). Research on cellulose eco-friendly dissolution and shaping will continue to be an important topic.

Several methods that have never been used for polysaccharides are find increasing consideration. This leads to the creation of new materials with novel and unexpected (for polysaccharides) properties. For example, bio-aerogels, obtained from gels using drying under supercritical conditions, are new materials born at the beginning of the 21st century (Zhao, Malfait, Guerrero-Alburquerque, Koebel, & Nyström, 2018). A deeper understanding of the fundamental principles of the processing technologies in the context of polysaccharide research will yield novel biobased materials with unique properties and fields of application.

Additive manufacturing for shaping non-melting polysaccharides will be developed. 3D printing of thermoplastics, mainly synthetic polymers, is now reasonably well explored. Printing of polysaccharide solutions involves other mechanisms of shape stabilisation. Bioprinting can underpin new biomedical applications (e.g., tailormade scaffolds hosting cells and bioactive agents for tissue engineering). We are now only at the beginning of a long, explorative way.

New or not previously used sources of polysaccharides are now under investigation in the view of a biorefinery approach. Microalgae, which have been considered mainly as a source of biofuels, are also a promising sustainable feedstock containing polysaccharides. Extraction and separation of polysaccharides require new approaches and the development of novel technologies such as, for example, filtration systems for fractionation. Until recently, hemicelluloses have been regarded as a waste, when they could, instead, be used for the production of chemicals (e.g., furfural), biooils, or second-generation feedstock for fermentation. The diversity of known microbial species is constantly increasing. New exopolysaccharides are, for example, yeast-based. Many of them have peculiar biochemical or physical properties, which allow the development of new applications (Rahbar Saadat, Yari Khosroushahi, & Pourghassem Gargari, 2021). Efforts are ongoing to establish recombinant cell factories for agar (and other natural polysaccharides) production to satisfy the current market and enable new applications. One possibility to decrease waste and environmental impact is to produce less refined products and make use of the physical properties of these products. It is not always required to go to high purity; on the contrary, lower purity can even lead to products with improved properties compared to pure products. This approach opens opportunities for new applications with fewer processing steps.

### 3.2.3. Required research activities

One of the general approaches to be taken is interdisciplinarity. As polysaccharides are now considered in applications that were not even imagined 10–20 years ago, new (for polysaccharides) processing methods should be used and adapted to these applications.
generating harmful by-products, is a stimulating research field expected to capture enormous interest in the coming years.

## 3.2. Processing of polysaccharides

### 3.2.1. Current challenges

Processing is defined as transforming raw materials into finished products of certain shapes and properties. Polysaccharides are polymers; however, not all processing approaches developed for synthetic polymers can be and are currently used. Most polysaccharides are not thermoplastic. The difficulty in shaping polysaccharides results, in part, from strong intra- and intermolecular interactions between macromolecules, which prevent chains' mobility needed for melt processing.

The majority of natural polysaccharides are thus processed via solubilisation. Depending on the application, many of them remain in a dissolved state: for example, pectin, alginate, and carrageenans are used as viscosity modifiers, gelling agents, and gels in food, cosmetics, and pharmaceutics. These polymers can also be shaped into films by casting solutions followed by solvent evaporation. Cellulose dissolved via the viscose process is spun into fibres for textile and non-woven applications or cast into films. Much progress has been made in finding cellulose dissolution options (Lyocell process, dissolution in ionic liquids) as an alternative to the viscose process, which is very polluting (Liebert, 2010). Chitin is very difficult to dissolve and it is thus transformed into chitosan, which can then be dissolved in acidic aqueous media and processed into fibres or films (Pillai, Paul, & Sharma, 2009). To use starch for food applications and for packaging, it is usually prepared as an aqueous paste, which is the result of a gelatinisation process (Wang & Copeland, 2013). Foams and films are made from thermoplastic starch for packaging and agricultural applications.

The above concerns the processing of neat polysaccharides. However, except in very rare cases, polysaccharides exist in nature as mixtures with various other substances of low or high molecular weight. The classical example is natural fibres which are complex composite materials of polysaccharides (cellulose and hemicelluloses) and non-polysaccharide polymers (lignin) organised in a sort of an interpenetrated network. Alginate or carrageenan in seaweeds coexist with cellulose, proteins, minerals, and lipids. Chitin in crustacean shells or in mushrooms is mixed with minerals and proteins. Extraction of polysaccharides from these natural composites is thus needed for their further processing. The extraction methods are well known, but optimisation is still needed to improve efficiency and decrease the use of harmful chemicals.

Polysaccharides can also be processed in suspension after extraction or disassembly of native polysaccharide particles and fibrils from biomass. This process involves multiple steps, and it is resource and energy intensive. Finally, chemically modified polysaccharides, so-called polysaccharide derivatives, make a class of polymers with some of them being thermoplastics or easy to dissolve in water (e.g., cellulose ethers). Several cellulose esters can be melt processed in the same way as synthetic polymers. They can also be dissolved to cast films and spin fibres and non-wovens. Starch derivatives are processed and used in a similar way as cellulose derivatives.

Microorganisms as cell factories play several roles in the context of polysaccharide chemistry and processing (Tiwari, Sasmal, Kataria, & Devi, 2020). Many bacteria produce exopolysaccharides, which are industrially quite important, such as xanthan. Other polysaccharides produced by microbes (such as hyaluronic acid, kefiran, or gellan) are currently used for biomedical applications (Mohd Nadzir, Nurhayati, Idris, & Nguyen, 2021). Bacterial cellulose is of special importance for biomedical applications due to its high purity. Its properties can be modified by varying the cell factory or the production conditions, opening new fields of cellulose chemistry, processing, and applications. Levans are of increasing interest; they are fructans of bacterial origin with quite interesting properties. Microorganisms are also producing polysaccharide-modifying enzymes and can thus be used as whole cell

catalysts for polysaccharide modifications. As such, microbial catalysts open new opportunities for polysaccharide chemistry and processing.

### 3.2.2. Expected achievements and developments in the next 20 years

Biorefinery approaches are and will be in the focus of polysaccharide processing: their extraction, purification and shaping. New processing methods (in the context of polysaccharides) have begun to be applied. The management of resources must be sustainable, and their use must be efficient, with minimum waste, and environmentally friendly. This requires reconsideration of the traditional ways of polysaccharide processing, which opens prospects for innovation. For example, new eco-friendly solvents and their recovery are a focus of research. This concerns cellulose dissolution and shaping, which is an old but still a very relevant problem. Some ionic liquids have been demonstrated to be powerful cellulose solvents, and the properties of fibres spun from these solvents compete with those obtained from viscose and Lyocell processes (Hummel et al., 2016). Still, ionic liquids are expensive, and to date, their recovery is complicated. There is a revival of interest in aqueous hydroxide-based solvents to be used for cellulose shaping (Budtova & Navard, 2016). Research on cellulose eco-friendly dissolution and shaping will continue to be an important topic.

Several methods that have never been used for polysaccharides are find increasing consideration. This leads to the creation of new materials with novel and unexpected (for polysaccharides) properties. For example, bio-aerogels, obtained from gels using drying under supercritical conditions, are new materials born at the beginning of the 21st century (Zhao, Malfait, Guerrero-Alburquerque, Koebel, & Nyström, 2018). A deeper understanding of the fundamental principles of the processing technologies in the context of polysaccharide research will yield novel biobased materials with unique properties and fields of application.

Additive manufacturing for shaping non-melting polysaccharides will be developed. 3D printing of thermoplastics, mainly synthetic polymers, is now reasonably well explored. Printing of polysaccharide solutions involves other mechanisms of shape stabilisation. Bioprinting can underpin new biomedical applications (e.g., tailormade scaffolds hosting cells and bioactive agents for tissue engineering). We are now only at the beginning of a long, explorative way.

New or not previously used sources of polysaccharides are now under investigation in the view of a biorefinery approach. Microalgae, which have been considered mainly as a source of biofuels, are also a promising sustainable feedstock containing polysaccharides. Extraction and separation of polysaccharides require new approaches and the development of novel technologies such as, for example, filtration systems for fractionation. Until recently, hemicelluloses have been regarded as a waste, when they could, instead, be used for the production of chemicals (e.g., furfural), biooils, or second-generation feedstock for fermentation. The diversity of known microbial species is constantly increasing. New exopolysaccharides are, for example, yeast-based. Many of them have peculiar biochemical or physical properties, which allow the development of new applications (Rahbar Saadat, Yari Khosroushahi, & Pourghassem Gargari, 2021). Efforts are ongoing to establish recombinant cell factories for agar (and other natural polysaccharides) production to satisfy the current market and enable new applications. One possibility to decrease waste and environmental impact is to produce less refined products and make use of the physical properties of these products. It is not always required to go to high purity; on the contrary, lower purity can even lead to products with improved properties compared to pure products. This approach opens opportunities for new applications with fewer processing steps.

### 3.2.3. Required research activities

One of the general approaches to be taken is interdisciplinarity. As polysaccharides are now considered in applications that were not even imagined 10–20 years ago, new (for polysaccharides) processing methods should be used and adapted to these applications.
Collaboration with researchers from other disciplines will be the way to advance. Another important aspect of processing is to use the sustainable and circular economy approaches.

The composite approach in polysaccharides will be more widely used, i.e., mixing polysaccharides with various organic or inorganic substances. Miscibility, dispersion, and distribution of the filler, compatibilisation (or not), filler transformation during mixing, biopolymer blends, and development of morphology during processing will have to be considered and adjusted according to the targeted application.

Processes for making polysaccharide materials with tuned morphology, such as porous polysaccharides, will continue to be developed. Drying methods as a part of processing will be in the focus as they control the porosity and morphology of the final material. Existing approaches should be coupled with specific polysaccharide functionalisation.

A deeper - and above all - systematic analysis of exopolysaccharides from newly identified microorganisms will be required to gain access to so far untapped natural resources. Of particular importance is the analysis and control of the biosynthesis of polysaccharides by microorganisms – the current knowledge is, in many cases, limited. Often peculiar sugars are required in biochemically activated form for the synthesis of polysaccharides. The mechanisms of how a polysaccharide is produced and transported to the extracellular space is often unclear. Finally, the special properties of the polysaccharides often derive from specific modifications (such as pyruvylation, sulfation and many more). Detailed knowledge about the mechanisms of biosynthesis and the involved enzymes would allow us to rationally design polysaccharides by metabolic engineering. A close collaboration of biochemists, molecular biologists, and industrial microbiologists will bring microbial polysaccharide production to a new level. Developments in the field of synthetic biology can contribute to designing and developing these tailormade new products.

## 3.3. Emerging polysaccharide applications in electric energy storage and harvesting

### 3.3.1. Current challenges

Electric energy supply and utilisation are essential for the functioning of the society. In May 2021, the International Energy Agency IEA released its roadmap to global net-zero emissions, analysing the implications of existing net zero pledges and showing a pathway to achieving net-zero emissions in electric energy production globally by 2050. In connection to this, a tremendous annual increase in off-grid electric energy storage and distribution is already appearing. Materials' solutions that can contribute to CO₂ reduction, as with many other aspects of sustainability, are getting increased attention scientifically and technically. In this respect, polysaccharides have shown promising performance and are foreseen to play an increasingly important role as components with multifaceted functionalities in electronics and energy materials in the coming decades (Zhao et al., 2021).

### 3.3.2. Expected achievements and developments in the next 20 years

In the next 20 years, distributed electric energy systems will continue to grow in importance. Besides the emerging need for off-grid storage in the electric power industry to efficiently balance the intermittent production output from wind and solar power generation, the electrification of the automotive sector and the increased digitalisation and continuous development in the area of internet-of-things will be the main drivers (Schlemmer, Selinger, Hobisch, & Spirk, 2021). In the development of batteries and supercapacitors, it can be expected that fossil-derived fully synthetic polymer materials will be continuously replaced with renewable polymers (Pérez-Madrigal, Edo, & Alemán, 2016). Carboxymethyl cellulose can be used as a binder, capable of compensating the volume change while maintaining stable performance and possibly exhibit self-healing. Also, other cellulose derivatives, alginate, gum arabic, xanthan gum, and chitosan, have shown to be promising binders. Nanopaper

from cellulose nanofibrils has been applied successfully as separators in batteries, and further development is expected (Jabbour, Bongiovanni, Chaussy, Gerbaldi, & Beneventi, 2013). Moreover, polymer electrolytes in the form of gels and solids are well-suited components in certain battery applications. Different cellulose derivatives, chitosan, and algal-based polysaccharides have shown to be alternatives to conventional synthetic polymer electrolytes. This relatively new field is expected to gain in importance.

Supercapacitors are considered as one of the potential candidates in the domain of energy storage devices for future generations. There is a variety of applications covering large application areas; excess energy storage, powering electric vehicles, replacing batteries in electronics, as well as balancing the grid from fluctuations that arise in solar and wind power generation. Supercapacitors have generated great interest due to their higher power density, longer cycle lifetime and faster charge-discharge rate than batteries (Pushparaj et al., 2007). The electrodes often consist of carbon material, e.g., graphene or carbon nanotubes, as active materials and binders. Here, cellulose fibrils have been proven very suitable as binders as well as dispersion agents without decreasing the electrical performance. Cellulose nanofibrils and paper used as permeable separators that facilitate ion transport in charging and discharging, are also showing promising results (Nyholm, Nyström, Mihranyan, & Strømme, 2011).

Small-scale electronics are booming for the internet-of-things, wireless sensor networks, smart city design, and medical applications. The components of such devices typically require minimal amounts of power, but this becomes challenging when considering a large network of devices numbering in the billions. Maintenance costs will explode as the number of distributed micro-electronics increases, considering solutions where batteries must be replaced. Recent efforts to develop new types of energy harvesting systems, such as triboelectric nanogenerators, are therefore expected to ascend (Wu, Wang, Ding, Guo, & Wang, 2019). Owing to their attractive attributes, triboelectric nanogenerators have been successfully applied for harvesting all kinds of insignificant but abundant mechanical energy, such as vibrations, human body motion, wind power, and water motion. In this context, electrical insulating materials (dielectric materials) are necessary and superior. The reported performance profiles of cellulose, cellulose derivatives, and other polysaccharides in triboelectric nanogenerator applications are encouraging (Torres & De-la-Torre, 2021; Zhang et al., 2020). Future development is expected in many different real-world applications, where for instance, supercapacitors also can be included, realising battery-less internet-of-things solutions for sensing and monitoring. Moreover, polysaccharide materials can find their place due to their low toxicity and sufficient durability-(bio)degradability performance. Self-sufficient, fully green, and even transient (i.e., degrading in a controlled way in a biological environment), system solutions could be constructed in the future when combining these technologies.

A more sophisticated utilisation of paper is also expected. A practical approach for producing electronic devices on any flexible substrate is transfer technologies, which are currently a hot topic in wearable electronics platforms. There are already several types of transfer technologies available where all cell layers are initially deposited on a standard donor substrate (e.g., silicon) and after that they are transferred to the receiver substrate (i.e., speciality paper sheets). Fully printed solar cells on speciality paper substrates can also be realised for large-scale applications. Polysaccharide-based materials can be used in photonic applications (Ha, Fang, & Zhitenev, 2018). Photonic crystals enable a host of practical applications such as nonlinear waveguides, advanced anti-counterfeiting structures, and low-energy-consuming displays. Since structured cellulose-based composites exhibit high reflectivity, tuneable within the visible and near-infrared regions of the optical spectrum, applications ranging from colour filters to smart clothing designs and solar-gain-regulating building technologies can be expected. Cellulose-based materials can be designed for either cold or hot climates without compromising visible-range optical transparency. The use of
Collaboration with researchers from other disciplines will be the way to advance. Another important aspect of processing is to use the sustainable and circular economy approaches.

The composite approach in polysaccharides will be more widely used, i.e., mixing polysaccharides with various organic or inorganic substances. Miscibility, dispersion, and distribution of the filler, compatibilisation (or not), filler transformation during mixing, biopolymer blends, and development of morphology during processing will have to be considered and adjusted according to the targeted application.

Processes for making polysaccharide materials with tuned morphology, such as porous polysaccharides, will continue to be developed. Drying methods as a part of processing will be in the focus as they control the porosity and morphology of the final material. Existing approaches should be coupled with specific polysaccharide functionalisation.

A deeper and above all systematic analysis of exopolysaccharides from newly identified microorganisms will be required to gain access to so far untapped natural resources. Of particular importance is the analysis and control of the biosynthesis of polysaccharides by microorganisms – the current knowledge is, in many cases, limited. Often peculiar sugars are required in biochemically activated form for the synthesis of polysaccharides. The mechanisms of how a polysaccharide is produced and transported to the extracellular space is often unclear. Finally, the special properties of the polysaccharides often derive from specific modifications (such as pyruvylation, sulfation and many more). Detailed knowledge about the mechanisms of biosynthesis and the involved enzymes would allow us to rationally design polysaccharides by metabolic engineering. A close collaboration of biochemists, molecular biologists, and industrial microbiologists will bring microbial polysaccharide production to a new level. Developments in the field of synthetic biology can contribute to designing and developing these tailormade new products.

## 3.3. Emerging polysaccharide applications in electric energy storage and harvesting

### 3.3.1. Current challenges

Electric energy supply and utilisation are essential for the functioning of the society. In May 2021, the International Energy Agency IEA released its roadmap to global net-zero emissions, analysing the implications of existing net zero pledges and showing a pathway to achieving net-zero emissions in electric energy production globally by 2050. In connection to this, a tremendous annual increase in off-grid electric energy storage and distribution is already appearing. Materials' solutions that can contribute to CO₂ reduction, as with many other aspects of sustainability, are getting increased attention scientifically and technically. In this respect, polysaccharides have shown promising performance and are foreseen to play an increasingly important role as components with multifaceted functionalities in electronics and energy materials in the coming decades (Zhao et al., 2021).

### 3.3.2. Expected achievements and developments in the next 20 years

In the next 20 years, distributed electric energy systems will continue to grow in importance. Besides the emerging need for off-grid storage in the electric power industry to efficiently balance the intermittent production output from wind and solar power generation, the electrification of the automotive sector and the increased digitalisation and continuous development in the area of internet-of-things will be the main drivers (Schlemmer, Selinger, Hobisch, & Spirk, 2021). In the development of batteries and supercapacitors, it can be expected that fossil-derived fully synthetic polymer materials will be continuously replaced with renewable polymers (Pérez-Madrigal, Edo, & Alemán, 2016). Carboxymethyl cellulose can be used as a binder, capable of compensating the volume change while maintaining stable performance and possibly exhibit self-healing. Also, other cellulose derivatives, alginate, gum arabic, xanthan gum, and chitosan, have shown to be promising binders. Nanopaper

from cellulose nanofibrils has been applied successfully as separators in batteries, and further development is expected (Jabbour, Bongiovanni, Chaussy, Gerbaldi, & Beneventi, 2013). Moreover, polymer electrolytes in the form of gels and solids are well-suited components in certain battery applications. Different cellulose derivatives, chitosan, and algal-based polysaccharides have shown to be alternatives to conventional synthetic polymer electrolytes. This relatively new field is expected to gain in importance.

Supercapacitors are considered as one of the potential candidates in the domain of energy storage devices for future generations. There is a variety of applications covering large application areas; excess energy storage, powering electric vehicles, replacing batteries in electronics, as well as balancing the grid from fluctuations that arise in solar and wind power generation. Supercapacitors have generated great interest due to their higher power density, longer cycle lifetime and faster charge-discharge rate than batteries (Pushparaj et al., 2007). The electrodes often consist of carbon material, e.g., graphene or carbon nanotubes, as active materials and binders. Here, cellulose fibrils have been proven very suitable as binders as well as dispersion agents without decreasing the electrical performance. Cellulose nanofibrils and paper used as permeable separators that facilitate ion transport in charging and discharging, are also showing promising results (Nyholm, Nyström, Mihranyan, & Strømme, 2011).

Small-scale electronics are booming for the internet-of-things, wireless sensor networks, smart city design, and medical applications. The components of such devices typically require minimal amounts of power, but this becomes challenging when considering a large network of devices numbering in the billions. Maintenance costs will explode as the number of distributed micro-electronics increases, considering solutions where batteries must be replaced. Recent efforts to develop new types of energy harvesting systems, such as triboelectric nanogenerators, are therefore expected to ascend (Wu, Wang, Ding, Guo, & Wang, 2019). Owing to their attractive attributes, triboelectric nanogenerators have been successfully applied for harvesting all kinds of insignificant but abundant mechanical energy, such as vibrations, human body motion, wind power, and water motion. In this context, electrical insulating materials (dielectric materials) are necessary and superior. The reported performance profiles of cellulose, cellulose derivatives, and other polysaccharides in triboelectric nanogenerator applications are encouraging (Torres & De-la-Torre, 2021; Zhang et al., 2020). Future development is expected in many different real-world applications, where for instance, supercapacitors also can be included, realising battery-less internet-of-things solutions for sensing and monitoring. Moreover, polysaccharide materials can find their place due to their low toxicity and sufficient durability-(bio)degradability performance. Self-sufficient, fully green, and even transient (i.e., degrading in a controlled way in a biological environment), system solutions could be constructed in the future when combining these technologies.

A more sophisticated utilisation of paper is also expected. A practical approach for producing electronic devices on any flexible substrate is transfer technologies, which are currently a hot topic in wearable electronics platforms. There are already several types of transfer technologies available where all cell layers are initially deposited on a standard donor substrate (e.g., silicon) and after that they are transferred to the receiver substrate (i.e., speciality paper sheets). Fully printed solar cells on speciality paper substrates can also be realised for large-scale applications. Polysaccharide-based materials can be used in photonic applications (Ha, Fang, & Zhitenev, 2018). Photonic crystals enable a host of practical applications such as nonlinear waveguides, advanced anti-counterfeiting structures, and low-energy-consuming displays. Since structured cellulose-based composites exhibit high reflectivity, tuneable within the visible and near-infrared regions of the optical spectrum, applications ranging from colour filters to smart clothing designs and solar-gain-regulating building technologies can be expected. Cellulose-based materials can be designed for either cold or hot climates without compromising visible-range optical transparency. The use of
cellulose in organic light-emitting diodes is another exciting application of polysaccharides in optoelectronic devices that will move forward.

### 3.3.3. Required research activities

In batteries and supercapacitors, the choice of electrolytes influences the stability of polysaccharides as binders and could also influence the properties of the membranes. More knowledge is needed to enhance future development.

Triboelectric research in the area of polysaccharides is still in its infancy. For instance, cellulose has several polymorphs that could influence the polarisation differently. Generally, an increased fundamental understanding of what is regulating the materials' triboelectric power output is needed, as well as how the performance can be optimised by different chemical and physical modifications. In transient electronics, an increased knowledge accumulation on how to control self-degradation is needed and can be expected.

At present, to use cellulose-based substrates in photovoltaic applications, several critical technological challenges need to be overcome to assure their performance and reproducibility. In this regard, several technical requirements such as thermal stability, mechanical properties, surface smoothness, high optical transparency and haze, as well as water barrier properties, need to be developed further.

From several viewpoints, forest-based polysaccharides might appear as inexhaustible biomass resources that could be utilised to solve almost everything. However, considering the whole system, it is evident that prioritizations will be necessary to fulfil sustainability requirements. As an example, in the production of nanofibres and cellulose derivatives to be used in the mentioned applications in this sub-sections, utilisation of many kinds of forest-based, agro-based and marine raw materials of lower quality than usual can be foreseen. This should be compared with the rather high demands on, for instance, the macro-fibre quality when producing pulps used for conventional and speciality paper-based products. From interdisciplinary perspectives, this makes it important and highly relevant to clearly identify and study feasible feedstocks other than wood, and from techno-economical perspectives, outline how to enable sustainable production.

## 4. Food & nutrition

Polysaccharides play a pivotal role in human nutrition and food structure design. Starches, being the major source of nutritional carbohydrates, were and remain to this date the prime focus of food research efforts. However, the last two decades saw a growing interest in complex oligosaccharides and polysaccharides and their assemblies that are not digestible by human enzymes. These types of carbohydrate materials are classified using the umbrella term dietary fibre.

Dietary fibre influence macronutrient digestibility and impact systemic, whole-body metabolism through a chain of physiological and metabolic events (Hoyles et al., 2018). These events begin with delayed gastric emptying, followed by the modulation of macronutrient digestion, and proceed to colonic fermentation of dietary fibre by the gut microbiome. At this point, fermentation-derived metabolites may enter the systemic circulation and plug into human metabolic pathways. Despite overwhelming epidemiological evidence supporting the link between dietary fibre intake and positive health outcomes, the intake of dietary fibre remains low across Western and Westernised diets (Hoyles et al., 2018).

Several research avenues have been pursued to tackle this challenge, including (i) identifying precise and specific physiological functionalities of dietary fibre, (ii) linking molecular and microstructure with functional properties, and (iii) developing new and enhancing existing fibre processing methods and techniques for their incorporation into food formulations. Conversely, new analytical and fibre characterisation techniques have become key enabling capabilities that underpin future advances, due to the complex and heterogeneous nature of carbohydrate structures. This roadmap identified several areas that will likely see

substantial advances, including:

- in-depth evaluation of the nutritional, physiological, and technological properties of fibre polysaccharides and prebiotic oligosaccharides in complex food matrices

- improved understanding of the structure and composition of individual fibre polysaccharides and their complex assemblies

- mapping and monitoring dietary fibre transformation during fermentation, as well as uncovering the structural and dynamic interactions governing fermentation, resulting metabolites and mucosal interactions

- understanding chemical interactions between fibres and other nutrients and ingredients, such as proteins, fats, minerals, bile acids, and small bioactive molecules

- precision modification and transformation processes rooted in the in-depth understanding of fibre structure, from individual complex molecules to complex microstructures

- development of next-generation less-processed ingredients from upcycled and valorised side streams

- implementation of highly accurate, high-throughput, and high-speed characterisation methods

- polysaccharide sequencing through chemical and enzymatic fingerprinting to allow the distinction of polysaccharides with different patterns of substitution

- utilisation of highly advanced imaging techniques for characterising intact tissues and food products, including super-resolution microscopy, NMR imaging, and imaging mass spectrometry (MS)

- development of dedicated methods for the specific extraction of well-defined polysaccharides from inaccessible and insoluble matrices using physical techniques and environmentally friendly solvents

Within the strategic horizon of the next two decades, a more detailed understanding of the structural characteristics and structure-function-relationships of dietary fibre will enable the development of targeted dietary fibre polysaccharides with programmable interactions, rheological properties (gelling, viscosity), physiological responses (fermentability, immune modulation), as well as techno-functional properties to benefit public health, boost food system resilience, and achieve sustainable food processing and manufacturing. Taking a broader perspective, the goal is to ensure that consumers trust their food, the food is affordable, and the food journey from farm-to-fork is transparent.

### 4.1. Dietary fibre

#### 4.1.1. Current challenges

Significant achievements of the past few decades saw a marked increase in the level of insight into the digestibility and fermentability of naturally occurring dietary fibre. In addition, there has been significant progress in exploring the functional capabilities of various fibre ingredients, including their roles as structuring-, gelling-, or thickening agents in technological applications.

Currently, dietary fibre reported on food package labels is referred to as total dietary fibre without specifying its functionality. There are several definitions for dietary fibre that specify the ingredients included in the total sum of fibre polysaccharides and, perhaps even more importantly, those that are not. From a polysaccharide perspective, it is generally important to identify fibre polysaccharides that are part of the total dietary fibre per the current definition. Even more crucially, it is important to specify, at the very minimum, the proportions of soluble and insoluble dietary fibre. Ideally, even more detailed aspects of the fibre structure should be considered, as they directly impact fermentability and interactions with other components in both the food and the gut. Only well-characterised fibre polysaccharides will allow for meaningful comparisons in the discussion on fibre functionalities and properties (Gidley & Yakubov, 2019).
cellulose in organic light-emitting diodes is another exciting application of polysaccharides in optoelectronic devices that will move forward.

### 3.3.3. Required research activities

In batteries and supercapacitors, the choice of electrolytes influences the stability of polysaccharides as binders and could also influence the properties of the membranes. More knowledge is needed to enhance future development.

Triboelectric research in the area of polysaccharides is still in its infancy. For instance, cellulose has several polymorphs that could influence the polarisation differently. Generally, an increased fundamental understanding of what is regulating the materials' triboelectric power output is needed, as well as how the performance can be optimised by different chemical and physical modifications. In transient electronics, an increased knowledge accumulation on how to control self-degradation is needed and can be expected.

At present, to use cellulose-based substrates in photovoltaic applications, several critical technological challenges need to be overcome to assure their performance and reproducibility. In this regard, several technical requirements such as thermal stability, mechanical properties, surface smoothness, high optical transparency and haze, as well as water barrier properties, need to be developed further.

From several viewpoints, forest-based polysaccharides might appear as inexhaustible biomass resources that could be utilised to solve almost everything. However, considering the whole system, it is evident that prioritizations will be necessary to fulfil sustainability requirements. As an example, in the production of nanofibres and cellulose derivatives to be used in the mentioned applications in this sub-sections, utilisation of many kinds of forest-based, agro-based and marine raw materials of lower quality than usual can be foreseen. This should be compared with the rather high demands on, for instance, the macro-fibre quality when producing pulps used for conventional and speciality paper-based products. From interdisciplinary perspectives, this makes it important and highly relevant to clearly identify and study feasible feedstocks other than wood, and from techno-economical perspectives, outline how to enable sustainable production.

## 4. Food & nutrition

Polysaccharides play a pivotal role in human nutrition and food structure design. Starches, being the major source of nutritional carbohydrates, were and remain to this date the prime focus of food research efforts. However, the last two decades saw a growing interest in complex oligosaccharides and polysaccharides and their assemblies that are not digestible by human enzymes. These types of carbohydrate materials are classified using the umbrella term *dietary fibre*.

Dietary fibre influence macronutrient digestibility and impact systemic, whole-body metabolism through a chain of physiological and metabolic events (Hoyles et al., 2018). These events begin with delayed gastric emptying, followed by the modulation of macronutrient digestion, and proceed to colonic fermentation of dietary fibre by the gut microbiome. At this point, fermentation-derived metabolites may enter the systemic circulation and plug into human metabolic pathways. Despite overwhelming epidemiological evidence supporting the link between dietary fibre intake and positive health outcomes, the intake of dietary fibre remains low across Western and Westernised diets (Hoyles et al., 2018).

Several research avenues have been pursued to tackle this challenge, including (i) identifying precise and specific physiological functionalities of dietary fibre, (ii) linking molecular and microstructure with functional properties, and (iii) developing new and enhancing existing fibre processing methods and techniques for their incorporation into food formulations. Conversely, new analytical and fibre characterisation techniques have become key enabling capabilities that underpin future advances, due to the complex and heterogeneous nature of carbohydrate structures. This roadmap identified several areas that will likely see

substantial advances, including:

- in-depth evaluation of the nutritional, physiological, and technological properties of fibre polysaccharides and prebiotic oligosaccharides in complex food matrices

- improved understanding of the structure and composition of individual fibre polysaccharides and their complex assemblies

- mapping and monitoring dietary fibre transformation during fermentation, as well as uncovering the structural and dynamic interactions governing fermentation, resulting metabolites and mucosal interactions

- understanding chemical interactions between fibres and other nutrients and ingredients, such as proteins, fats, minerals, bile acids, and small bioactive molecules

- precision modification and transformation processes rooted in the in-depth understanding of fibre structure, from individual complex molecules to complex microstructures

- development of next-generation less-processed ingredients from upcycled and valorised side streams

- implementation of highly accurate, high-throughput, and high-speed characterisation methods

- polysaccharide sequencing through chemical and enzymatic fingerprinting to allow the distinction of polysaccharides with different patterns of substitution

- utilisation of highly advanced imaging techniques for characterising intact tissues and food products, including super-resolution microscopy, NMR imaging, and imaging mass spectrometry (MS)

- development of dedicated methods for the specific extraction of well-defined polysaccharides from inaccessible and insoluble matrices using physical techniques and environmentally friendly solvents

Within the strategic horizon of the next two decades, a more detailed understanding of the structural characteristics and structure-function-relationships of dietary fibre will enable the development of targeted dietary fibre polysaccharides with programmable interactions, rheological properties (gelling, viscosity), physiological responses (fermentability, immune modulation), as well as techno-functional properties to benefit public health, boost food system resilience, and achieve sustainable food processing and manufacturing. Taking a broader perspective, the goal is to ensure that consumers trust their food, the food is affordable, and the food journey from farm-to-fork is transparent.

### 4.1. Dietary fibre

#### 4.1.1. Current challenges

Significant achievements of the past few decades saw a marked increase in the level of insight into the digestibility and fermentability of naturally occurring dietary fibre. In addition, there has been significant progress in exploring the functional capabilities of various fibre ingredients, including their roles as structuring-, gelling-, or thickening agents in technological applications.

Currently, dietary fibre reported on food package labels is referred to as *total dietary fibre* without specifying its functionality. There are several definitions for dietary fibre that specify the ingredients included in the total sum of fibre polysaccharides and, perhaps even more importantly, those that are not. From a polysaccharide perspective, it is generally important to identify fibre polysaccharides that are part of the total dietary fibre per the current definition. Even more crucially, it is important to specify, at the very minimum, the proportions of soluble and insoluble dietary fibre. Ideally, even more detailed aspects of the fibre structure should be considered, as they directly impact fermentability and interactions with other components in both the food and the gut. Only well-characterised fibre polysaccharides will allow for meaningful comparisons in the discussion on fibre functionalities and properties (Gidley & Yakubov, 2019).
In the current state of the matter, dietary fibre in the studies are primarily classified as soluble or insoluble – a factor that indirectly describes the length as well as the level of internal hierarchical structures between the individual polysaccharide types that may govern the interactions between individual fibre molecules. Fibre solubility is directly associated with the capacity of fibres to form physical structures and networks that enhance bonding between fibre chains. Insoluble fibre ranges from dense and weakly hydrated brans to complex gel-like cell wall structures (Gartaula et al., 2018). In these structures, the cellulosic nano- and micro-fibrils are surrounded by a hydrated matrix of hemi-celluloses and pectins, forming complex structures of physically and partially tethered or cross-linked gels. Fermentability of insoluble fibre is highly dependable on the degree of cross-linking of non-cellulosic components and their structural complexity (Harris et al., 2023). On the other end of the spectrum, we find soluble fibre that are more readily fermentable by the intestinal microbiota owing to the better accessibility of the soluble fibre as a substrate for fermentation compared to its high molecular weight and insoluble counterpart. This connection between fibre structure and fermentability is very well established for individual fibre types but still insufficiently understood at the level of fibre mixtures and complex microbial populations that are dynamically changing and vary significantly between individuals (Makki, Deehan, Walter, & Bäckhed, 2018). Furthermore, the interactions of dietary fibre with small nutritionally relevant molecules, which may govern the availability of various nutrients, remain insufficiently understood. Similarly, understanding of the direct impact of fibre on immune cells has been demonstrated for certain fibre types, but systematic studies on this topic are still lacking (Beukema, Faas, & de Vos, 2020).

### 4.1.2. Expected achievements and developments in the next 20 years

The next two decades can be expected to proceed towards more in-depth research in dietary fibre polysaccharides towards a more detailed understanding of their structural characteristics and their features in terms of nutritional and technological activities in the complex food matrices. A key aspect to address will be to gain a better understanding of the structure-function-relationships of various individual fibre polysaccharides, i.e., the various chemical species of molecules, instead of the soluble vs. insoluble fractions as the type of fibre may have a larger impact on the effect than the overall intake (Thomson, Garcia, & Edwards, 2021). The past decades of research have demonstrated that in addition to the total dietary fibre content, it is essential to measure the proportions of soluble and insoluble fractions due to their specific nutritional and technological properties. Yet, the research in the past years has also shown that even more detail in the fibre characterisation is needed, especially for the soluble fibre fraction, as the functionality of the fibre is dependent on the solubility, molecular weight, fine structure, branching and further factors, which all have a direct impact for example on fibre fermentability (Beukema et al., 2020). Fermentation of the polysaccharides will be a central theme governing dietary fibre research in the future.

Understanding the role of complex fibre mixtures as substrates for the complex mixtures of intestinal microbiota is still very simplified, and the factors governing fermentation and resulting metabolites are somewhat poorly characterised. Furthermore, dynamic interactions with the intestinal mucosa and mucosal microbes, as well as the direct impact of fibre on immunological responses, are only recently established and are not yet understood in detail. Both fermentation and mucosal interactions are heavily impacted by the viscosity of fibre polysaccharides in the gut lumen – a factor which has a high variability between individuals and one that is poorly predictable by *in vitro* methods. Finally, the chemical interactions between fibre and other small molecules and nutrients (e.g., sugars, bile acids, minerals) are still insufficiently understood, despite being acknowledged as one of the mechanisms governing nutrient absorption.

### 4.1.3. Required research activities

Future research in nutritional polysaccharides should aim to establish the relationship between various fibre characteristics and the resulting health effects. On a molecular level, the first step is to use advanced analytical techniques to obtain a detailed characterisation of the structural features of the polysaccharides (e.g., monosaccharide composition, substitution patterns, linkage types, see Section 3.3). Though such structural characterisation has been carried out in the past, information on the variability of such structural features within various plant sources and after their processing for food use has not been fully established. Furthermore, most of the studies on the health-promoting effects of nutritional polysaccharides have compared various fibre species (such as arabinoxylan vs. beta-glucan vs. pectin), but not different versions of a single fibre type. (e.g., relative ratios of monosaccharides involved, substitution type and degree, and type of glycosidic linkages) and how these vary in their technological functionalities or nutritional properties (especially those related to digestibility and fermentation) that rely on the specificity and access of microbial and/or exogenous enzymes to hydrolyse the fibres. Such assessment is important to be carried out with mixtures of dietary fibre and microbial cultures to create realistic conditions for complex mixtures to understand cascades of reactions, where one microbial species converts one species of fibre polysaccharides into a state that is better fermentable by the next groups of microbes.

Characterisation of fibre polysaccharides and their technological and nutritional properties should be assessed at various length scales, from oligosaccharide via soluble polysaccharides to large insoluble polysaccharides. For example, arabinoxylans (main dietary fibre component in grains such as wheat, rye, barley, and corn) but also other grain fibres are known to have significantly different properties at different scales. In the native seeds, insoluble high molecular weight arabinoxylans contribute up to 90 % of total arabinoxylan and exert a strong water-holding capacity that contributes to the technological properties of doughs, as well as bread during storage (Maina et al., 2021). Processing of the arabinoxylan through milling, extrusion, enzyme treatment, fermentation, baking, or other similar processes solubilises part of the insoluble arabinoxylans to lower molecular weight water-soluble arabinoxylans, which increase the viscosity of solutions, and build gel structures, as well as increase digestibility and fermentability. Finally, when digested to the shortest oligosaccharide level, arabinoxylans show again improved digestibility and additional functions as anti-microbial agents. Assessment of the fermentability of dietary fibre and their optimisation also links directly to the efficiency of fibre-rich materials as animal feeds, which may be optimised through fibre processing. Such overall improvement of conversion factors has an incredible effect on the sustainability of food chains through the better conversion factors and thereby improved use of existing materials, but also the optimised use of new food raw materials from protein and fibre-rich side streams from microalgae, insects, and new plant sources.

At the macromolecular level, the assessment of the fibre functionality should go beyond the currently well-established functions related to viscosity increase in the gut lumen. As any ingested food is significantly diluted by gastric fluids (several hundred millilitres depending on the individual), a pure increase in viscosity is unlikely the only mechanism governing the modulation of the absorption rate of nutrients in the gut. Recent advances in the methodologies to characterise and quantify interactions of the dietary fibre with mucosal glycoproteins or absorbable nutrients should be systematically applied to explain the interactions between different fibres and nutritionally relevant associated molecules (Padayachee, Day, Howell, & Gidley, 2017). Only with a thorough understanding of the interactions, it is possible to optimise them in foods for best health outcomes.

Finally, to maximise the nutritional benefits of fibre-rich foods and fibre ingredients, a systemic understanding of the various mechanisms of action for fibres at different conditions is needed to decide, whether for example structural features of one fibre are more important than the
In the current state of the matter, dietary fibre in the studies are primarily classified as soluble or insoluble – a factor that indirectly describes the length as well as the level of internal hierarchical structures between the individual polysaccharide types that may govern the interactions between individual fibre molecules. Fibre solubility is directly associated with the capacity of fibres to form physical structures and networks that enhance bonding between fibre chains. Insoluble fibre ranges from dense and weakly hydrated brans to complex gel-like cell wall structures (Gartaula et al., 2018). In these structures, the cellulosic nano- and micro-fibrils are surrounded by a hydrated matrix of hemi-celluloses and pectins, forming complex structures of physically and partially tethered or cross-linked gels. Fermentability of insoluble fibre is highly dependable on the degree of cross-linking of non-cellulosic components and their structural complexity (Harris et al., 2023). On the other end of the spectrum, we find soluble fibre that are more readily fermentable by the intestinal microbiota owing to the better accessibility of the soluble fibre as a substrate for fermentation compared to its high molecular weight and insoluble counterpart. This connection between fibre structure and fermentability is very well established for individual fibre types but still insufficiently understood at the level of fibre mixtures and complex microbial populations that are dynamically changing and vary significantly between individuals (Makki, Deehan, Walter, & Bäckhed, 2018). Furthermore, the interactions of dietary fibre with small nutritionally relevant molecules, which may govern the availability of various nutrients, remain insufficiently understood. Similarly, understanding of the direct impact of fibre on immune cells has been demonstrated for certain fibre types, but systematic studies on this topic are still lacking (Beukema, Faas, & de Vos, 2020).

### 4.1.2. Expected achievements and developments in the next 20 years

The next two decades can be expected to proceed towards more in-depth research in dietary fibre polysaccharides towards a more detailed understanding of their structural characteristics and their features in terms of nutritional and technological activities in the complex food matrices. A key aspect to address will be to gain a better understanding of the structure-function-relationships of various individual fibre polysaccharides, i.e., the various chemical species of molecules, instead of the soluble vs. insoluble fractions as the type of fibre may have a larger impact on the effect than the overall intake (Thomson, Garcia, & Edwards, 2021). The past decades of research have demonstrated that in addition to the total dietary fibre content, it is essential to measure the proportions of soluble and insoluble fractions due to their specific nutritional and technological properties. Yet, the research in the past years has also shown that even more detail in the fibre characterisation is needed, especially for the soluble fibre fraction, as the functionality of the fibre is dependent on the solubility, molecular weight, fine structure, branching and further factors, which all have a direct impact for example on fibre fermentability (Beukema et al., 2020). Fermentation of the polysaccharides will be a central theme governing dietary fibre research in the future.

Understanding the role of complex fibre mixtures as substrates for the complex mixtures of intestinal microbiota is still very simplified, and the factors governing fermentation and resulting metabolites are somewhat poorly characterised. Furthermore, dynamic interactions with the intestinal mucosa and mucosal microbes, as well as the direct impact of fibre on immunological responses, are only recently established and are not yet understood in detail. Both fermentation and mucosal interactions are heavily impacted by the viscosity of fibre polysaccharides in the gut lumen – a factor which has a high variability between individuals and one that is poorly predictable by *in vitro* methods. Finally, the chemical interactions between fibre and other small molecules and nutrients (e.g., sugars, bile acids, minerals) are still insufficiently understood, despite being acknowledged as one of the mechanisms governing nutrient absorption.

### 4.1.3. Required research activities

Future research in nutritional polysaccharides should aim to establish the relationship between various fibre characteristics and the resulting health effects. On a molecular level, the first step is to use advanced analytical techniques to obtain a detailed characterisation of the structural features of the polysaccharides (e.g., monosaccharide composition, substitution patterns, linkage types, see Section 3.3). Though such structural characterisation has been carried out in the past, information on the variability of such structural features within various plant sources and after their processing for food use has not been fully established. Furthermore, most of the studies on the health-promoting effects of nutritional polysaccharides have compared various fibre species (such as arabinoxylan vs. beta-glucan vs. pectin), but not different versions of a single fibre type. (e.g., relative ratios of monosaccharides involved, substitution type and degree, and type of glycosidic linkages) and how these vary in their technological functionalities or nutritional properties (especially those related to digestibility and fermentation) that rely on the specificity and access of microbial and/or exogenous enzymes to hydrolyse the fibres. Such assessment is important to be carried out with mixtures of dietary fibre and microbial cultures to create realistic conditions for complex mixtures to understand cascades of reactions, where one microbial species converts one species of fibre polysaccharides into a state that is better fermentable by the next groups of microbes.

Characterisation of fibre polysaccharides and their technological and nutritional properties should be assessed at various length scales, from oligosaccharide via soluble polysaccharides to large insoluble polysaccharides. For example, arabinoxylans (main dietary fibre component in grains such as wheat, rye, barley, and corn) but also other grain fibres are known to have significantly different properties at different scales. In the native seeds, insoluble high molecular weight arabinoxylans contribute up to 90 % of total arabinoxylan and exert a strong water-holding capacity that contributes to the technological properties of doughs, as well as bread during storage (Maina et al., 2021). Processing of the arabinoxylan through milling, extrusion, enzyme treatment, fermentation, baking, or other similar processes solubilises part of the insoluble arabinoxylans to lower molecular weight water-soluble arabinoxylans, which increase the viscosity of solutions, and build gel structures, as well as increase digestibility and fermentability. Finally, when digested to the shortest oligosaccharide level, arabinoxylans show again improved digestibility and additional functions as anti-microbial agents. Assessment of the fermentability of dietary fibre and their optimisation also links directly to the efficiency of fibre-rich materials as animal feeds, which may be optimised through fibre processing. Such overall improvement of conversion factors has an incredible effect on the sustainability of food chains through the better conversion factors and thereby improved use of existing materials, but also the optimised use of new food raw materials from protein and fibre-rich side streams from microalgae, insects, and new plant sources.

At the macromolecular level, the assessment of the fibre functionality should go beyond the currently well-established functions related to viscosity increase in the gut lumen. As any ingested food is significantly diluted by gastric fluids (several hundred millilitres depending on the individual), a pure increase in viscosity is unlikely the only mechanism governing the modulation of the absorption rate of nutrients in the gut. Recent advances in the methodologies to characterise and quantify interactions of the dietary fibre with mucosal glycoproteins or absorbable nutrients should be systematically applied to explain the interactions between different fibres and nutritionally relevant associated molecules (Padayachee, Day, Howell, & Gidley, 2017). Only with a thorough understanding of the interactions, it is possible to optimise them in foods for best health outcomes.

Finally, to maximise the nutritional benefits of fibre-rich foods and fibre ingredients, a systemic understanding of the various mechanisms of action for fibres at different conditions is needed to decide, whether for example structural features of one fibre are more important than the
optimised fermentability of another fibre. The ultimate aim of the research in the upcoming years should be to make even more detailed recommendations for fibre intakes that are not based on the total dietary fibre, but at the very least based on proportions of soluble and insoluble fibres, or even better with the more ambitious goal of going for a more detailed level of fibre species and structures to fully appreciate and benefit from the enormous potential dietary fibre and the impact on our health and well-being they offer.

## 4.2. Food-structuring agents and in situ structurising polysaccharides

### 4.2.1. Current challenges

Isolated polysaccharides and complex polysaccharide assemblies, such as plant cell wall fragments, can be readily utilised to achieve a diverse spectrum of structures in foods and beverages: from viscosified fluids down to the formation of gels and complex solids, including composite coatings and films (Padayachee et al., 2017). Although polysaccharides represent a large share of the commodity and ingredient market, they are vastly underutilised within the food industry. The complexity of polysaccharide structures and the intricacy of their interactions make the task of rational material design difficult. Below, we outline four cornerstone challenges that have seen marked progress in the last decade.

The first challenge is the lack of precise control of the structuring mechanism and ability to tune underpinning interactions in order to manipulate and design targeted structures. This challenge, in part, is associated with the diversity of processing methods and structures: viscous and viscoelastic solutions, gels formed through physical and chemical cross-links, jammed semi-solids composed of concentrated suspensions, spun fibre and fibre mats, as well as liquid crystalline systems, such as cellulose colloids and nanocrystals. When polysaccharide structuring is underpinned by hydrogen bonding, charge- or dipole interactions, and van der Waals interactions, our understanding of processing-structure-function-relationship is fair. Significant gaps in understanding remain with regards to bond polarizability and establishing the precise space of polysaccharide conformations (Anggara et al., 2021; Anggara et al., 2023; Guvench et al., 2011; Watanabe, Yagi, Yanaka, Yamaguchi, & Kato, 2021). For hydrophobic and weakly hydrophilic polysaccharides, the description of entropic interactions, including the hydrophobic effect, remains elusive due to the lack of detailed experimental data and shortcomings in theoretical and modelling approaches (Benselfelt et al., 2016). Recent studies have been focusing on uncovering less explored facets of entropic interactions associated with extensive hydration of polysaccharides and the resulting interaction mechanisms rooted in the competition for water concepts (Lopez-Sanchez et al., 2022).

The second challenge is associated with a marked lack of understanding of the links between the structure of complex polysaccharides (including primary structure, functional group, side-chain motif distribution, and molecular architecture) and the resulting sets of physicochemical properties, such as surface adsorption and gel formation (Berglund et al., 2020; Yu, Stokes, & Yakubov, 2021). The need is driven by a significant increase in the use of complex polysaccharides derived from plant cell wall fragments, brans, and mucilages (Beukema et al., 2020; Yu et al., 2017). In addition, many emerging food ingredients are derived from the valorisation of waste or the upcycling of biomass. These processing methods result in the production of complex polysaccharide mixtures, the behaviour of which needs to be understood to make them useful in food structuring and as functional dietary fibre (Ren, Yakubov, Linter, MacNaughtan, & Foster, 2020; Williams, MikkelSEN, Flanagan, & Gidley, 2019).

The third challenge is associated with the need to develop efficient and sustainable processing methods for raw materials. These methods should be underpinned by quick and inexpensive assays for accurate and comprehensive structure characterisation. The recent decade saw the development of novel enzymes obtained through synthetic biology

approaches, complex fermentation processes, as well as food-grade chemical and physical combination methods, such as hydrothermal, microwave, tribomechanical, ultra-sound, cold plasma, and pulsed electric field processing (Foster et al., 2020). Underpinned by progress in genetic and metabolomic analysis, biotransformation technologies, in the form of controlled germination and complex, multi-stage fermentation, have received significant development for the production of targeted polysaccharides and fibre materials (Gan et al., 2021; Reid, Yakubov, & Lawrence, 2022). Finally, the generation of food-compatible deep eutectic solvents and advances in synthetic biology elevate the attractiveness of enzymatic and solvent/chemical modification methods. Equipped with new precision processing methods, we can target the development of novel, minimally processed food ingredients (Li, Zhang, & Dhital, 2019).

The fourth challenge is associated with the sourcing of environmentally sustainable ingredients and feedstocks. A shift from engineering applications to biomedical and food puts significant pressure on the traceability and safety of ingredients, including microbiological safety. In recent years, the food industry has experienced a shortage of commodity polysaccharides, such as guar gum and gum arabic, which are produced within localized geographical areas. The key to this challenge is the ability to find alternatives and develop a diverse portfolio of ingredients to avoid monoculture-focused agricultural production that heavily relies on a streamlined economy of scale and exploitative use of the land.

### 4.2.2. Expected achievements and developments in the next 20 years

The next decades should see the development of precision modification and transformation processes rooted in the in-depth understanding of the structure of polysaccharides and how it translates to technical or in-gut dietary fibre functionality. Building multi-scale models of polysaccharide assemblies: from individual complex molecules and architectures to complex microstructures, will allow precise targeting of specific structural features and modification of tailored structures, as well as introducing food-compatible functional chemical groups. These advances will be further underpinned by developments in sustainable agriculture, agile bioprocessing of complex feedstocks, and the use of machine learning and artificial intelligence (AI) approaches for process development and rapid/high-throughput screening.

It is envisaged that the next generation processing of the polysaccharide ingredients will see the rise of less processed materials such as primary/secondary cell wall particles and complex cellulosic pulps with high hemicellulose content. The wider use of a diverse base of fruits, vegetables, cereals, and pseudo cereals will see broader utilisation of complex macromolecules such as xylans and rhamnogalacturonans that feature complex side-chain decorations, atypical linkages, and intricate structural motifs. Materials derived from valorised waste streams, microalgae, and marine resources will receive a boost in the ability to reduce undesired protein and phenolic contaminants that may negatively impact food safety and quality.

The next generation of processing will continue focusing on targeting improved specificity and precision of traditional applications such as food structure (thickening/rheology, water holding), storage/shelf-life stability, and fat replacement. This will be achieved by superior control over fibre microstructure and assembly, molecular weight, branching, and chemical modification (e.g., acetylation, methylation, oxidation). Continuing effort will be placed on understanding *in situ* polysaccharide modification and transformation during oral processing, digestion and colonic fermentation.

The new technologies to modify fibres will be enabled through a range of pre- and post-farm gate facilities, ranging from large bio-refineries to smaller scale and agile foundries and food processing lines. It is envisaged that new advances in polysaccharide analytics, in-line sensors, and high-throughput screening will enable the adoption of machine learning and internet-of-things approaches to deliver precise, safe, and cost-effective manufacture with embedded principles of
optimised fermentability of another fibre. The ultimate aim of the research in the upcoming years should be to make even more detailed recommendations for fibre intakes that are not based on the total dietary fibre, but at the very least based on proportions of soluble and insoluble fibres, or even better with the more ambitious goal of going for a more detailed level of fibre species and structures to fully appreciate and benefit from the enormous potential dietary fibre and the impact on our health and well-being they offer.

## 4.2. Food-structuring agents and in situ structurising polysaccharides

### 4.2.1. Current challenges

Isolated polysaccharides and complex polysaccharide assemblies, such as plant cell wall fragments, can be readily utilised to achieve a diverse spectrum of structures in foods and beverages: from viscosified fluids down to the formation of gels and complex solids, including composite coatings and films (Padayachee et al., 2017). Although polysaccharides represent a large share of the commodity and ingredient market, they are vastly underutilised within the food industry. The complexity of polysaccharide structures and the intricacy of their interactions make the task of rational material design difficult. Below, we outline four cornerstone challenges that have seen marked progress in the last decade.

The first challenge is the lack of precise control of the structuring mechanism and ability to tune underpinning interactions in order to manipulate and design targeted structures. This challenge, in part, is associated with the diversity of processing methods and structures: viscous and viscoelastic solutions, gels formed through physical and chemical cross-links, jammed semi-solids composed of concentrated suspensions, spun fibre and fibre mats, as well as liquid crystalline systems, such as cellulose colloids and nanocrystals. When polysaccharide structuring is underpinned by hydrogen bonding, charge- or dipole interactions, and van der Waals interactions, our understanding of processing-structure-function-relationship is fair. Significant gaps in understanding remain with regards to bond polarizability and establishing the precise space of polysaccharide conformations (Anggara et al., 2021; Anggara et al., 2023; Guvench et al., 2011; Watanabe, Yagi, Yanaka, Yamaguchi, & Kato, 2021). For hydrophobic and weakly hydrophilic polysaccharides, the description of entropic interactions, including the hydrophobic effect, remains elusive due to the lack of detailed experimental data and shortcomings in theoretical and modelling approaches (Benselfelt et al., 2016). Recent studies have been focusing on uncovering less explored facets of entropic interactions associated with extensive hydration of polysaccharides and the resulting interaction mechanisms rooted in the competition for water concepts (Lopez-Sanchez et al., 2022).

The second challenge is associated with a marked lack of understanding of the links between the structure of complex polysaccharides (including primary structure, functional group, side-chain motif distribution, and molecular architecture) and the resulting sets of physicochemical properties, such as surface adsorption and gel formation (Berglund et al., 2020; Yu, Stokes, & Yakubov, 2021). The need is driven by a significant increase in the use of complex polysaccharides derived from plant cell wall fragments, brans, and mucilages (Beukema et al., 2020; Yu et al., 2017). In addition, many emerging food ingredients are derived from the valorisation of waste or the upcycling of biomass. These processing methods result in the production of complex polysaccharide mixtures, the behaviour of which needs to be understood to make them useful in food structuring and as functional dietary fibre (Ren, Yakubov, Linter, MacNaughtan, & Foster, 2020; Williams, MikkelSEN, Flanagan, & Gidley, 2019).

The third challenge is associated with the need to develop efficient and sustainable processing methods for raw materials. These methods should be underpinned by quick and inexpensive assays for accurate and comprehensive structure characterisation. The recent decade saw the development of novel enzymes obtained through synthetic biology

approaches, complex fermentation processes, as well as food-grade chemical and physical combination methods, such as hydrothermal, microwave, tribomechanical, ultra-sound, cold plasma, and pulsed electric field processing (Foster et al., 2020). Underpinned by progress in genetic and metabolomic analysis, biotransformation technologies, in the form of controlled germination and complex, multi-stage fermentation, have received significant development for the production of targeted polysaccharides and fibre materials (Gan et al., 2021; Reid, Yakubov, & Lawrence, 2022). Finally, the generation of food-compatible deep eutectic solvents and advances in synthetic biology elevate the attractiveness of enzymatic and solvent/chemical modification methods. Equipped with new precision processing methods, we can target the development of novel, minimally processed food ingredients (Li, Zhang, & Dhital, 2019).

The fourth challenge is associated with the sourcing of environmentally sustainable ingredients and feedstocks. A shift from engineering applications to biomedical and food puts significant pressure on the traceability and safety of ingredients, including microbiological safety. In recent years, the food industry has experienced a shortage of commodity polysaccharides, such as guar gum and gum arabic, which are produced within localized geographical areas. The key to this challenge is the ability to find alternatives and develop a diverse portfolio of ingredients to avoid monoculture-focused agricultural production that heavily relies on a streamlined economy of scale and exploitative use of the land.

### 4.2.2. Expected achievements and developments in the next 20 years

The next decades should see the development of precision modification and transformation processes rooted in the in-depth understanding of the structure of polysaccharides and how it translates to technical or in-gut dietary fibre functionality. Building multi-scale models of polysaccharide assemblies: from individual complex molecules and architectures to complex microstructures, will allow precise targeting of specific structural features and modification of tailored structures, as well as introducing food-compatible functional chemical groups. These advances will be further underpinned by developments in sustainable agriculture, agile bioprocessing of complex feedstocks, and the use of machine learning and artificial intelligence (AI) approaches for process development and rapid/high-throughput screening.

It is envisaged that the next generation processing of the polysaccharide ingredients will see the rise of less processed materials such as primary/secondary cell wall particles and complex cellulosic pulps with high hemicellulose content. The wider use of a diverse base of fruits, vegetables, cereals, and pseudo cereals will see broader utilisation of complex macromolecules such as xylans and rhamnogalacturonans that feature complex side-chain decorations, atypical linkages, and intricate structural motifs. Materials derived from valorised waste streams, microalgae, and marine resources will receive a boost in the ability to reduce undesired protein and phenolic contaminants that may negatively impact food safety and quality.

The next generation of processing will continue focusing on targeting improved specificity and precision of traditional applications such as food structure (thickening/rheology, water holding), storage/shelf-life stability, and fat replacement. This will be achieved by superior control over fibre microstructure and assembly, molecular weight, branching, and chemical modification (e.g., acetylation, methylation, oxidation). Continuing effort will be placed on understanding *in situ* polysaccharide modification and transformation during oral processing, digestion and colonic fermentation.

The new technologies to modify fibres will be enabled through a range of pre- and post-farm gate facilities, ranging from large bio-refineries to smaller scale and agile foundries and food processing lines. It is envisaged that new advances in polysaccharide analytics, in-line sensors, and high-throughput screening will enable the adoption of machine learning and internet-of-things approaches to deliver precise, safe, and cost-effective manufacture with embedded principles of
sustainability and life-cycle analysis.

### 4.2.3. Required research activities

Four key areas need to be addressed: (I) enzyme design, (II) combination processing methods, (III) high-throughput agile processing, and (IV) AI assisted food formulation and product design.

The current portfolio of enzymes, such as xylanases, is optimised for low side-chain substitution polysaccharides. The next generation of enzymes will target hyper-branched (complex) fibre molecules, enabling the processing of a much broader range of polysaccharide feedstocks. Conversely, reverse engineering approaches, such as the addition of sidechains or branches, will be supported by new research efforts in the field of glycosyltransferases. The discovery of enzymes will be facilitated by further insights into the germination and fermentation processes, allowing for the targeted assembly of complex plant cell wall-like structures with tuned fermentability and food-structuring capacity. Possible methods for such assemblies can draw inspiration from DNA-origami-like approaches, which are currently not feasible for polysaccharides due to a lack of precise structure control.

Combination processing methods that incorporate physical, enzymatic, and biotransformation approaches will address the challenges of effectively valorising and processing complex feedstocks. This will enable the reduction of anti-nutritional factors, minimise safety risks and allergy concerns, and achieve energy-efficient and optimised downstream processes such as dehydration, solubilisation, and extrusion.

Agile processing approaches that are more flexible and adaptable then conventional methods will further enhance the much-needed optimization in the food industry across different levels of technology readiness and production scales. When implemented at the points of primary production, such as farms and plantations, or in remote locations, such as for the extraction of marine bioresources, agile manufacturing platforms and on-demand processing facilities will significantly expand the range of feedstock materials available and enable the manufacturing of unique, yet affordable products. Minimising the time between harvest and processing plays a critical role in this process. These manufacturing platforms are envisaged to complement larger, more centralised facilities and manufacturing hubs. An integrated system of local, regional, and global manufacturing facilities will enable the rapid redirection of manufacturing resources, making processing streams of highly variable and diverse feedstocks efficient, resilient, and adaptable.

The improvement of operational efficiency and the ability to provide a quick response to food safety and quality issues are ideal areas for applying machine learning techniques and, more broadly, AI approaches. The impact of AI and machine learning spans various technology platforms, including planning, primary production, manufacturing, distribution, and social and behavioural domains. AI tools have enormous potential for enhancing communication with consumers and communities. They play a key role in augmenting consumer experiences and offer new avenues for product authentication, safety control, and monitoring. Perhaps the most remarkable area of AI application is the ability to map, segment, and contextualise consumer needs, motivations, and behaviours. Together with technological and scientific advances, this offers new strategies for influencing healthy food choices and the habitual adoption of nutritionally balanced diets.

## 4.3. Analytics of food polysaccharides

### 4.3.1. Current challenges

Typical for the analysis of complex carbohydrates in foods are the variability in the structure of the polysaccharides as well as the complex food matrix making the characterisation of carbohydrate structures challenging and complicated. In general, analysis of these essential molecules is underdeveloped, and we know more about the type and the level of micronutrients in foods (minerals, vitamins, amino acids) than

on dominating contingent of carbohydrates. Another dominant group of compounds in food are proteins, having their own omics approaches to recognise routinely hundreds of proteins present in complex mixtures, while sequencing procedures facilitate the determination of the sequence of individual amino acids in distinct proteins, independently of their size. Due to the complexity of polysaccharides composed of many isomeric monosaccharide building blocks having a huge variation in glycosidic linkages and being branched and decorated with non-carbohydrates substituents, carbohydrates are much more complicated to analyse than other macromolecules (Amicucci, Nandita, & Lebrilla, 2019). Another reason adding to the complexity of (food) polysaccharides is the fact that these secondary metabolites are synthesised and modified in planta at the same time, resulting in manifold carbohydrate structures dependent on the genetic properties of the plant species, environmental growing-, ripening-, and storage conditions. Furthermore, food processing will add to the complexity and diversity of carbohydrate structures present. The last complicating factor is the fact that a selected oligo- or polysaccharide as present in food may originate from the raw material used (cereal, fruit, vegetable) but might be added as a functional food ingredient as well, the latter possibly being modified/functionalised by the ingredient producer.

The above-mentioned variety and complexity of food carbohydrates have resulted in many different approaches and techniques, all dedicated to a selected (class of) oligo- or polysaccharide(s), dedicated/ specialised isolation and fractionation method or specialised analytical technique.

Among the best-characterised food carbohydrates are easily accessible oligosaccharides and individual polysaccharides as present as a food ingredient or dietary supplement. In addition, also human milk oligosaccharides are studied in quite some detail, recognising >200 different structures (Logtenberg et al., 2020). Human milk oligosaccharides and other prebiotic oligosaccharides like fructose oligosaccharides, inulin, isomalto-oligosaccharides, xylooligosaccharides, and galactooligosaccharides have been studied using infrared spectroscopy and a variety of MS techniques with a variety of analysers and dissociation techniques, e.g.; matrix-assisted laser desorption/ionization - time of flight (Maldi-TOF-) MS, tandem MS (MS²), electrospray iontrap MS³, and quadrupole TOF-MS, ionmobility (IM) MS (Hong, Yin, Nie, & Xie, 2021; Logtenberg et al., 2020; Ollivier et al., 2021; Wang, Zhao, Nie, Xie, & Li, 2021). These MS techniques are often preceded by powerful separation techniques like capillary electrophoresis, hydrophilic interaction liquid chromatography, porous graphitised carbon and high-performance anion exchange chromatography and reversed phase high pressure liquid chromatography (HPLC). The latter is especially used after derivatisation (labelling of reducing end, permethylation of free hydroxy groups, protection of sialic acid) of the oligosaccharide enabling a higher resolution, higher detector sensitivity or improved MS ionization of the targeted oligosaccharides. The presence of multiple isomers in a mixture (same mass, different linkage type or sequence of sugar residues) can be recognised by chromatography and by the rapid developing technique of (cyclic) IM-MS allowing a powerful gas-phase separation in the MS of isomeric oligosaccharides ranging from dimers to till degrees of polymerisation >10 during their travelling through an electric field. MS fragmentation pathways of carbohydrates have been recognised and documented in well-organised nomenclature and growing databases, but unfortunately, MS fragmentation routes strongly depend on oligosaccharides' structure, including sugar (linkage) type, anomeric position, and branching. An unambiguous identification of an individual, highly complex oligosaccharide may also involve laborious separation procedures followed by various 1D and 2D proton and carbon NMR spectroscopy techniques (Duus, Gotfredsen, & Bock, 2000). Combining of LC, MS, and NMR techniques have resulted in the recognition of >200 different human milk oligosaccharides, >100 different galactooligosaccharide structures, and numerous structures in other prebiotic mixtures, which are too often underestimated in functionality assays regarding their complexity.
sustainability and life-cycle analysis.

### 4.2.3. Required research activities

Four key areas need to be addressed: (I) enzyme design, (II) combination processing methods, (III) high-throughput agile processing, and (IV) AI assisted food formulation and product design.

The current portfolio of enzymes, such as xylanases, is optimised for low side-chain substitution polysaccharides. The next generation of enzymes will target hyper-branched (complex) fibre molecules, enabling the processing of a much broader range of polysaccharide feedstocks. Conversely, reverse engineering approaches, such as the addition of sidechains or branches, will be supported by new research efforts in the field of glycosyltransferases. The discovery of enzymes will be facilitated by further insights into the germination and fermentation processes, allowing for the targeted assembly of complex plant cell wall-like structures with tuned fermentability and food-structuring capacity. Possible methods for such assemblies can draw inspiration from DNA-origami-like approaches, which are currently not feasible for polysaccharides due to a lack of precise structure control.

Combination processing methods that incorporate physical, enzymatic, and biotransformation approaches will address the challenges of effectively valorising and processing complex feedstocks. This will enable the reduction of anti-nutritional factors, minimise safety risks and allergy concerns, and achieve energy-efficient and optimised downstream processes such as dehydration, solubilisation, and extrusion.

Agile processing approaches that are more flexible and adaptable then conventional methods will further enhance the much-needed optimization in the food industry across different levels of technology readiness and production scales. When implemented at the points of primary production, such as farms and plantations, or in remote locations, such as for the extraction of marine bioresources, agile manufacturing platforms and on-demand processing facilities will significantly expand the range of feedstock materials available and enable the manufacturing of unique, yet affordable products. Minimising the time between harvest and processing plays a critical role in this process. These manufacturing platforms are envisaged to complement larger, more centralised facilities and manufacturing hubs. An integrated system of local, regional, and global manufacturing facilities will enable the rapid redirection of manufacturing resources, making processing streams of highly variable and diverse feedstocks efficient, resilient, and adaptable.

The improvement of operational efficiency and the ability to provide a quick response to food safety and quality issues are ideal areas for applying machine learning techniques and, more broadly, AI approaches. The impact of AI and machine learning spans various technology platforms, including planning, primary production, manufacturing, distribution, and social and behavioural domains. AI tools have enormous potential for enhancing communication with consumers and communities. They play a key role in augmenting consumer experiences and offer new avenues for product authentication, safety control, and monitoring. Perhaps the most remarkable area of AI application is the ability to map, segment, and contextualise consumer needs, motivations, and behaviours. Together with technological and scientific advances, this offers new strategies for influencing healthy food choices and the habitual adoption of nutritionally balanced diets.

## 4.3. Analytics of food polysaccharides

### 4.3.1. Current challenges

Typical for the analysis of complex carbohydrates in foods are the variability in the structure of the polysaccharides as well as the complex food matrix making the characterisation of carbohydrate structures challenging and complicated. In general, analysis of these essential molecules is underdeveloped, and we know more about the type and the level of micronutrients in foods (minerals, vitamins, amino acids) than

on dominating contingent of carbohydrates. Another dominant group of compounds in food are proteins, having their own omics approaches to recognise routinely hundreds of proteins present in complex mixtures, while sequencing procedures facilitate the determination of the sequence of individual amino acids in distinct proteins, independently of their size. Due to the complexity of polysaccharides composed of many isomeric monosaccharide building blocks having a huge variation in glycosidic linkages and being branched and decorated with non-carbohydrates substituents, carbohydrates are much more complicated to analyse than other macromolecules (Amicucci, Nandita, & Lebrilla, 2019). Another reason adding to the complexity of (food) polysaccharides is the fact that these secondary metabolites are synthesised and modified in planta at the same time, resulting in manifold carbohydrate structures dependent on the genetic properties of the plant species, environmental growing-, ripening-, and storage conditions. Furthermore, food processing will add to the complexity and diversity of carbohydrate structures present. The last complicating factor is the fact that a selected oligo- or polysaccharide as present in food may originate from the raw material used (cereal, fruit, vegetable) but might be added as a functional food ingredient as well, the latter possibly being modified/functionalised by the ingredient producer.

The above-mentioned variety and complexity of food carbohydrates have resulted in many different approaches and techniques, all dedicated to a selected (class of) oligo- or polysaccharide(s), dedicated/ specialised isolation and fractionation method or specialised analytical technique.

Among the best-characterised food carbohydrates are easily accessible oligosaccharides and individual polysaccharides as present as a food ingredient or dietary supplement. In addition, also human milk oligosaccharides are studied in quite some detail, recognising >200 different structures (Logtenberg et al., 2020). Human milk oligosaccharides and other prebiotic oligosaccharides like fructose oligosaccharides, inulin, isomalto-oligosaccharides, xylooligosaccharides, and galactooligosaccharides have been studied using infrared spectroscopy and a variety of MS techniques with a variety of analysers and dissociation techniques, e.g.; matrix-assisted laser desorption/ionization - time of flight (Maldi-TOF-) MS, tandem MS (MS²), electrospray iontrap MS¹, and quadrupole TOF-MS, ionmobility (IM) MS (Hong, Yin, Nie, & Xie, 2021; Logtenberg et al., 2020; Ollivier et al., 2021; Wang, Zhao, Nie, Xie, & Li, 2021). These MS techniques are often preceded by powerful separation techniques like capillary electrophoresis, hydrophilic interaction liquid chromatography, porous graphitised carbon and high-performance anion exchange chromatography and reversed phase high pressure liquid chromatography (HPLC). The latter is especially used after derivatisation (labelling of reducing end, permethylation of free hydroxy groups, protection of sialic acid) of the oligosaccharide enabling a higher resolution, higher detector sensitivity or improved MS ionization of the targeted oligosaccharides. The presence of multiple isomers in a mixture (same mass, different linkage type or sequence of sugar residues) can be recognised by chromatography and by the rapid developing technique of (cyclic) IM-MS allowing a powerful gas-phase separation in the MS of isomeric oligosaccharides ranging from dimers to till degrees of polymerisation >10 during their travelling through an electric field. MS fragmentation pathways of carbohydrates have been recognised and documented in well-organised nomenclature and growing databases, but unfortunately, MS fragmentation routes strongly depend on oligosaccharides' structure, including sugar (linkage) type, anomeric position, and branching. An unambiguous identification of an individual, highly complex oligosaccharide may also involve laborious separation procedures followed by various 1D and 2D proton and carbon NMR spectroscopy techniques (Duus, Gotfredsen, & Bock, 2000). Combining of LC, MS, and NMR techniques have resulted in the recognition of >200 different human milk oligosaccharides, >100 different galactooligosaccharide structures, and numerous structures in other prebiotic mixtures, which are too often underestimated in functionality assays regarding their complexity.
A first challenge and often a pitfall in the analysis of complex carbohydrates is the determination of all sugars present. Many different hydrolysis conditions are being used, balancing between full hydrolysis of cellulosic fibres, pectins, and other rather robust polymers and conditions not damaging any fewer stable sugars like arabinose and sialic acid (Kamerling & Gerwig, 2007). A second challenge is to learn more about polysaccharides' structure in order to link this info to the specific technological or biofunctional characteristics of such polysaccharides. During the isolation of the polysaccharide from the plant/food matrix, attention should be paid to remove as much as possible of other (interconnected) food compounds like proteins, lipids, and starch, which could complicate carbohydrate analysis, without changing the structure of targeted polysaccharides.

Insoluble polysaccharides are usually solubilised by specific extrac-
tants like buffers, chelating agents, weak and strong alkaline solutions,
or dimethyl sulfoxide. However, seldom will only one specific poly-
saccharide class be obtained. Therefore, obtained extracts are often
further fractionated based on branching, size, and charge using gradual
ethanol precipitation and by (semi)preparative size exclusion chroma-
tography and ion-exchange chromatography. Physical characteristics of
food polysaccharides in models and in food systems can be monitored by
a wide range of quite diverse techniques ranging from microscopy
(confocal laser scanning microscopy, electron microscopy, atomic force
microscopy) to shear force-, viscosity-, and texture analysers.

4.3.2. *Expected achievements and developments in the next 20 years*

To be able to monitor the fate, structure, and modification of food
polysaccharides in the plant, in food processing, and during digestion/
fermentation after consumption, new methods should become available
to analyse complex carbohydrate samples quickly but still accurately
within hours instead of days, weeks, or even months. Highly advanced
imaging techniques of intact tissues and food products based on mi-
croscopy, NMR, and MS (MALDI TOF MS, reflection and transmission
geometry laser ablation electrospray ionization MS and nano-desorption
electrospray ionization - orbitrap or cyclic-IM-MS) will be further
developed and become available for the food industry to monitor re-
actions, accumulation of reaction products, and disappearance of other
compounds at certain spots within the food product. Capsules now
readily available for drug delivery at specific locations in the intestinal
tract of patients will be converted to remote sampling devices, able to
sample non-invasively lumen content to be analysed for microbiota
composition, remaining dietary fibre, short chain fatty acids, and
glycosidic degradation products like oligosaccharides, which will help
us to consider personalised nutrition and to understand much better the
role of dietary fibre and prebiotics for a healthy gut.

Dedicated methods to specifically extract special polysaccharides from inaccessible and insoluble matrices using planetary ball milling, ionic liquids, and specific food-compatible deep eutectic solvents will provide new insights in how polysaccharides are involved in the interaction and interactive network within food products. These insights will lead to approaches to use the entire crop in food products by tailoring the polysaccharides *in situ* by dedicated enzymes and by novel food processes like high-pressure processes, special shear forces, and ultrasound technologies. Functionalising fruits, vegetables, and cereals' own polysaccharides will also lower the ongoing need to add functional polysaccharide ingredients to tailor food simply by making use of the products' own polysaccharide portfolio.

The characterisation of polysaccharides by sequencing the poly-
saccharides' sugar chain through chemical and enzymatic fingerprinting
and subjecting the diagnostic oligosaccharides released to LC-MS iden-
tification and quantification will lead to an adequate understanding but
also to improved functionality of polysaccharide ingredients (Jermendi,
Beukema, van den Berg, de Vos, & Schols, 2022). This sequence-based
information will allow the distinction between polysaccharides having
the same chemical characteristics but different substitution pattern, i.e.,
distribution of substituents over the polysaccharides' backbone.

Examples are already available to illustrate that differences in substi-
tution patterns are causing huge variance in gelling, and viscosifying
properties, in fermentability and in immune stimulation.

4.3.3. *Required research activities*

The key to establish structure-function-relationships of food poly-
saccharides is to run functionality assays with well-characterised poly-
saccharides instead of poorly described averaged recipes and diets.
Know what you investigate! This is not easy to achieve when working
with mixtures of different structural molecules, all belonging to the same
polymer class. This challenge becomes even larger when dealing with
the insoluble and inaccessible food matrix. Accurate visualisation and
characterisation procedures should be further developed and improved,
but even more importantly, they should gain factors in analytical run
time and should even become high throughput. Manual fractionation
protocols should be automated, and different forms of chromatography
could be combined in the 2D-LC-MS-MS-MS approach. For such, enzy-
matic and chemical methods to on-line, in between analytical columns,
yield diagnostic oligomers within a range of degrees of polymerisation
from 2 to 20 should be developed without losing labile substituents like
arabinose, acetyl- and feruloyl groups, and methyl esters. Methods
available in research should be transferred to a more routine environ-
ment while still delivering as many details as possible. Big data ap-
proaches should assist in controlling the almost unlimited flow of MS
and MSn spectra from automated extraction-2D-LC-reaction-LC-MSn to
identify individual oligosaccharides, and accurate and adequate data-
bases should be built.

**5. Polysaccharides in biomedical and well-being applications**

The inherent biological and pharmacological activities, biocompat-
ibility, biodegradability, distinctive physical and chemical properties of
polysaccharides, and the versatility of their derivatives have been
extensively exploited to create biomaterials and medicinal products
applied to clinical practice, under clinical trials, or in *in vivo* experi-
ments. The scientific and biotechnological interest devoted to poly-
saccharides in biomedicine conflates five principal research topics: 1) Bioactive Polysaccharides, 2) Cosmetics, 3) Drug Delivery and Nano-
medicine, 4) Medical Devices, and 5) Tissue Engineering and Regener-
ative Medicine. Such a platform can lead to the development of products
with a lower carbon footprint at the end of the product cycle and a
valuable alternative to polymers derived from fossil sources. Some
considerations for innovative clinical applications and translation, pro-
cessability, performance improvement, market introduction, and future
perspectives of next-generation polysaccharide biomaterials are high-
lighted below:

- selective chemical and enzymatic functionalisation strategies of polysaccharides using sustainable approaches

- processes for extraction and purification of polysaccharides involving green chemistry

- accurate, rapid, and high-throughput methods for multiparametric analyses of chemical and physical properties of formulations

- pharmacokinetic studies to determine absorption, distribution, metabolism, and excretion of polysaccharide derivatives

- modelling and simulation methods for the investigation of structure-performance-relationship investigation

- personalised pharmaceutical dosage forms and improvement of drug activity and bioavailability

- development of new targeting agents and smart carriers for drugs

- medical devices with anti-inflammatory, anti-infective, and anti-coagulant activities

- use of polysaccharides to produce protective medical equipment

- design and (bio-)fabrication technologies of biomimetic and func-
tional multiscale constructs, combined with cells or bioactive factors,
with highly controlled properties
A first challenge and often a pitfall in the analysis of complex carbohydrates is the determination of all sugars present. Many different hydrolysis conditions are being used, balancing between full hydrolysis of cellulosic fibres, pectins, and other rather robust polymers and conditions not damaging any fewer stable sugars like arabinose and sialic acid (Kamerling & Gerwig, 2007). A second challenge is to learn more about polysaccharides' structure in order to link this info to the specific technological or biofunctional characteristics of such polysaccharides. During the isolation of the polysaccharide from the plant/food matrix, attention should be paid to remove as much as possible of other (interconnected) food compounds like proteins, lipids, and starch, which could complicate carbohydrate analysis, without changing the structure of targeted polysaccharides.

Insoluble polysaccharides are usually solubilised by specific extrac-
tants like buffers, chelating agents, weak and strong alkaline solutions,
or dimethyl sulfoxide. However, seldom will only one specific poly-
saccharide class be obtained. Therefore, obtained extracts are often
further fractionated based on branching, size, and charge using gradual
ethanol precipitation and by (semi)preparative size exclusion chroma-
tography and ion-exchange chromatography. Physical characteristics of
food polysaccharides in models and in food systems can be monitored by
a wide range of quite diverse techniques ranging from microscopy
(confocal laser scanning microscopy, electron microscopy, atomic force
microscopy) to shear force-, viscosity-, and texture analysers.

**4.3.2. Expected achievements and developments in the next 20 years**

To be able to monitor the fate, structure, and modification of food
polysaccharides in the plant, in food processing, and during digestion/
fermentation after consumption, new methods should become available
to analyse complex carbohydrate samples quickly but still accurately
within hours instead of days, weeks, or even months. Highly advanced
imaging techniques of intact tissues and food products based on mi-
croscopy, NMR, and MS (MALDI TOF MS, reflection and transmission
geometry laser ablation electrospray ionization MS and nano-desorption
electrospray ionization - orbitrap or cyclic-IM-MS) will be further
developed and become available for the food industry to monitor re-
actions, accumulation of reaction products, and disappearance of other
compounds at certain spots within the food product. Capsules now
readily available for drug delivery at specific locations in the intestinal
tract of patients will be converted to remote sampling devices, able to
sample non-invasively lumen content to be analysed for microbiota
composition, remaining dietary fibre, short chain fatty acids, and
glycosidic degradation products like oligosaccharides, which will help
us to consider personalised nutrition and to understand much better the
role of dietary fibre and prebiotics for a healthy gut.

Dedicated methods to specifically extract special polysaccharides from inaccessible and insoluble matrices using planetary ball milling, ionic liquids, and specific food-compatible deep eutectic solvents will provide new insights in how polysaccharides are involved in the interaction and interactive network within food products. These insights will lead to approaches to use the entire crop in food products by tailoring the polysaccharides *in situ* by dedicated enzymes and by novel food processes like high-pressure processes, special shear forces, and ultrasound technologies. Functionalising fruits, vegetables, and cereals' own polysaccharides will also lower the ongoing need to add functional polysaccharide ingredients to tailor food simply by making use of the products' own polysaccharide portfolio.

The characterisation of polysaccharides by sequencing the poly-
saccharides' sugar chain through chemical and enzymatic fingerprinting
and subjecting the diagnostic oligosaccharides released to LC-MS iden-
tification and quantification will lead to an adequate understanding but
also to improved functionality of polysaccharide ingredients (Jermendi,
Beukema, van den Berg, de Vos, & Schols, 2022). This sequence-based
information will allow the distinction between polysaccharides having
the same chemical characteristics but different substitution pattern, i.e.,
distribution of substituents over the polysaccharides' backbone.

Examples are already available to illustrate that differences in substi-
tution patterns are causing huge variance in gelling, and viscosifying
properties, in fermentability and in immune stimulation.

**4.3.3. Required research activities**

The key to establish structure-function-relationships of food poly-
saccharides is to run functionality assays with well-characterised poly-
saccharides instead of poorly described averaged recipes and diets.
Know what you investigate! This is not easy to achieve when working
with mixtures of different structural molecules, all belonging to the same
polymer class. This challenge becomes even larger when dealing with
the insoluble and inaccessible food matrix. Accurate visualisation and
characterisation procedures should be further developed and improved,
but even more importantly, they should gain factors in analytical run
time and should even become high throughput. Manual fractionation
protocols should be automated, and different forms of chromatography
could be combined in the 2D-LC-MS-MS-MS approach. For such, enzy-
matic and chemical methods to on-line, in between analytical columns,
yield diagnostic oligomers within a range of degrees of polymerisation
from 2 to 20 should be developed without losing labile substituents like
arabinose, acetyl- and feruloyl groups, and methyl esters. Methods
available in research should be transferred to a more routine environ-
ment while still delivering as many details as possible. Big data ap-
proaches should assist in controlling the almost unlimited flow of MS
and MSn spectra from automated extraction-2D-LC-reaction-LC-MSn to
identify individual oligosaccharides, and accurate and adequate data-
bases should be built.

**5. Polysaccharides in biomedical and well-being applications**

The inherent biological and pharmacological activities, biocompat-
ibility, biodegradability, distinctive physical and chemical properties of
polysaccharides, and the versatility of their derivatives have been
extensively exploited to create biomaterials and medicinal products
applied to clinical practice, under clinical trials, or in *in vivo* experi-
ments. The scientific and biotechnological interest devoted to poly-
saccharides in biomedicine conflates five principal research topics: 1) Bioactive Polysaccharides, 2) Cosmetics, 3) Drug Delivery and Nano-
medicine, 4) Medical Devices, and 5) Tissue Engineering and Regener-
ative Medicine. Such a platform can lead to the development of products
with a lower carbon footprint at the end of the product cycle and a
valuable alternative to polymers derived from fossil sources. Some
considerations for innovative clinical applications and translation, pro-
cessability, performance improvement, market introduction, and future
perspectives of next-generation polysaccharide biomaterials are high-
lighted below:

- selective chemical and enzymatic functionalisation strategies of polysaccharides using sustainable approaches

- processes for extraction and purification of polysaccharides involving green chemistry

- accurate, rapid, and high-throughput methods for multiparametric analyses of chemical and physical properties of formulations

- pharmacokinetic studies to determine absorption, distribution, metabolism, and excretion of polysaccharide derivatives

- modelling and simulation methods for the investigation of structure-performance-relationship investigation

- personalised pharmaceutical dosage forms and improvement of drug activity and bioavailability

- development of new targeting agents and smart carriers for drugs

- medical devices with anti-inflammatory, anti-infective, and anti-coagulant activities

- use of polysaccharides to produce protective medical equipment

- design and (bio-)fabrication technologies of biomimetic and func-
tional multiscale constructs, combined with cells or bioactive factors,
with highly controlled properties