# Evaluation of pectin and fiber in Cambodian mango peel and pulp from young to ripe maturity stages - a tool for industry

Adrien Servent, Marvin Soto, Tina Julien, Sela Cham, Savery Yon, Chanvorleak Phat, Elen Morm

► To cite this version:

Adrien Servent, Marvin Soto, Tina Julien, Sela Cham, Savery Yon, et al.. Evaluation of pectin and fiber in Cambodian mango peel and pulp from young to ripe maturity stages - a tool for industry. Applied Food Research, 2026, 6 (1), pp.101671. 10.1016/j.afres.2026.101671. hal-05476117

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# Evaluation of pectin and fiber in Cambodian mango peel and pulp from young to ripe maturity stages – a tool for industry

Adrien Servent<sup>a,b,e,*</sup> <sup>ID</sup>, Marvin Soto<sup>e</sup>, Tina Julien<sup>a,b</sup>, Sela Cham<sup>c</sup>, Savery Yon<sup>c</sup>, Chanvorleak Phat<sup>c,d</sup> <sup>ID</sup>, Elen Morm<sup>c,d</sup>

## ARTICLE INFO

### Keywords:

- Mango peel

- Mango pulp

- Pectin

- Fiber

- Decision support tool

- Animal feed

## ABSTRACT

In tropical countries, the mango sector generates high volumes of byproducts (peel, seeds, rejects, etc.) that need to be valorized. This research carried out on Cambodian Keo Romeat mango waste, was undertaken to support the mango industry. The aim was to better understand how ripening stage and processing method impact the final quality of the products, e.g., animal feed, especially as regards to soluble pectin and fiber content. Mangoes were selected from four ripening stages from young (i.e., green) to over-ripe mango, and processed using blanching and drying, drying or freeze-drying. The characterization of macronutrient (pectin, fiber, ash, lipid, carbohydrate and moisture) content was achieved in pulp and peel for each ripening stage and process treatment. Results showed that both processing and ripening had a significant impact on fiber and soluble pectin content even if ripening always had a greater effect. Maximizing both pectin and fiber contents in the mango pulp or peel was not possible, since the anti-correlation between their concentrations during ripening presented an R² of >0.7. Indeed, when fiber content decreased, the pectin content increased in mango peel and pulp. A simple 4-dimensional data representation was helpful for industrial growers and processors, enabling them to make suitable and appropriate choices between ripening and the processing needs according to the desired product quality without requiring specialized knowledge in food science.

## 1. Introduction

The mango fruit, classified as *Anacardiaceae* family, *Mangifera* genus, and *indica* L. specie, is a tropical climacteric fruit that is important for many southern countries in Africa, Latin America and Asia. In Cambodia for instance, the production of mango, mainly Keo Romeat and Keo Chen varieties, reached about one million tons in 2020 (Chin et al., 2024; MAFF, 2021). This crop generates significant quantities of byproducts at different moments of the production chain, estimated to be between 30 % and 60 % of total production, with a mass distribution of 33–85 % pulp, 9–40 % seeds, and 7–24 % peel (Jahurul et al., 2015; Kaur et al., 2022, 2025; Kim et al., 2012). Scientists have developed technological solutions to valorize these byproducts, mainly by the extraction and purification of bioactive micronutrients (such as carotenoids,

polyphenols, etc.) or macronutrients via sustainable high-tech green-technologies (e.g., ultrasound, microwaves, pulsed electric fields, pressurization, etc.) (García-Mahecha et al., 2023; Quintana et al., 2021; Tesfaye, 2017). In the last decade, the value of these approaches has been demonstrated for the design of natural dyes, biopolymers, purified starch extracts, biofibers, and biofuels (Tesfaye, 2017). Despite the significant number of studies on mango byproduct valorization, most of these approaches are impracticable in a low-resource context, resulting in most of the waste being discarded. The main reason is that these ‘high value products’ are not yet affordable by southern farmers either financially or in terms of the knowledge required to implement the innovation of byproduct valorization (Suri & Udry, 2022), which is often carried out far from the field and non-inclusive (e.g., set up without the main stakeholders). This lack of realism in terms of southern farm

<footnote><sup>a</sup> Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR Qualisud, 34398 Montpellier Cedex 5, France</footnote>

<footnote><sup>b</sup> Qualisud, Univ. Montpellier, CIRAD, Montpellier SupAgro, Université d'Avignon, Université de La Réunion, Montpellier, France</footnote>

<footnote><sup>c</sup> Faculty of Chemical and Food Engineering, Institute of Technology of Cambodia, Russian Federation Blvd., P.O. Box 86, Phnom Penh, Cambodia</footnote>

<footnote><sup>d</sup> Research and Innovation Center, Institute of Technology of Cambodia, Russian Federation Blvd., P.O. Box 86, Phnom Penh, Cambodia</footnote>

<footnote><sup>e</sup> Centro Nacional de Ciencia y Tecnología de Alimentos (CITA), Universidad de Costa Rica (UCR), Ciudad Universitaria Rodrigo Facio, código postal 11501-2060, San José, Costa Rica</footnote>

<footnote>* Corresponding author.
E-mail address: adrien.servent@cirad.fr (A. Servent).</footnote>
low-tech infrastructures and amenities (electricity, running water, location, pilot construction and operation, etc.), make that most mango byproducts are generally either spread on the ground or used for animal feed. This last option is more accessible but already a challenge, as regulations governing the quality of products authorized for animal feed vary by country or coalition of countries (European-Commission, 2025; FDA, 2025).

Among macronutrients of nutritional interest, mango peel and pulp are rich in dietary fibers (soluble pectin, cellulose and hemicellulose), and to a lesser extent in lipids and proteins (Abdul Aziz et al., 2012; Wongkaew et al., 2021). They are also known to be rich in bioactive compounds, mainly polyphenols sometimes bound to dietary fiber and carotenoids (Jahurul et al., 2015). Soluble pectin in mango peel constitutes approximately 20 g·100 g⁻¹ of dry matter (DM) and insoluble fiber around 40 g·100 g⁻¹ of DM (Larrauri et al., 1996), while both are found at approximately 15 g·100 g⁻¹ of DM in mango pulp (Geerkens et al., 2015). The structure of mango pectic substances and techno-functional properties have also been specifically examined (Cárdenas-Pérez et al., 2018; Sirisakulwat et al., 2008; Wongkaew et al., 2021). Mango presents significant differences in soluble and insoluble fiber contents during ripening, compared to other fruits such as avocado, bananas, apples, or citrus (Prasanna et al., 2007). The mass and the structure of fiber contents in mango pulp and peel are known to change with the ripening stage. In the pulp, it was reported that elevated polygalacturonase, cellulase and pectinesterase activities have several impacts on fiber content and textural functionalities (viscosity etc.). The speed of these enzymatic activities depends on many factors during mango ripening and varies greatly from one variety to another (Varanyanond et al., 1999). However, the diversity of enzymatic and non-enzymatic degradation pathways of fibers during fruit growth or processing might contribute to explaining the divergent values found in the literature (El-Zoghbi 1994; Prasanna et al., 2007). For example, pectin content decreased from 60 to 18 g·100 g⁻¹ of DM in Keitt mango pulp between the green and ripe stages (Roe & Bruemmer, 1981). In the peel, the same decreases were observed, from 25–42 g·100 g⁻¹ to 13–17 g·100 g⁻¹ of DM between the same stages (Sirisakulwat et al., 2008). However, other studies have reported an increase in soluble pectin during mango ripening, sometimes doubling the content because of the degradation of insoluble pectic substances (Medlicott & Jeger, 1987; Tandon & Kalra, 1984; Varanyanond et al., 1999). Changes in insoluble fiber are no clearer. Its content in the pulp during mango ripening was reported as being stable (Akinlolu-Ojo et al., 2022; Tharanathan et al., 2006), but other authors observed a 40 % decrease of the initial content after ripening (Ibarra-Garza et al., 2015) because of depolymerization and enzymatic degradation by cellulases and hemicellulases (Yashoda et al., 2006). The same is true for the peel. For example, an increase of around 10 g·100 g⁻¹ of DM between green and ripe peels was observed, whilst in other studies the content was constant after ripening (Abdul Aziz et al., 2012; Ajila & Prasada Rao, 2013). These statements are inconsistent with each other. Additionally, the structure of mango pectin and fiber was also proved to change during ripening (Cárdenas-Pérez et al., 2018) and processing (Wongkaew et al., 2021).

To our knowledge, no study has clearly focused on the mass evolution of soluble and insoluble fibers and the link between them during mango ripening in both peel and pulp. Therefore, this study aimed to better characterize this link along the ripening of mango. It also assessed simple farm-level processing methods, i.e., drying and blanching, to stabilize byproducts prior to export for use in animal feed. The experimentation site and the intended industrial application were both located in Cambodia, and the whole study was built with and for an industrial using real on-farm conditions. One industrial sample, processed in these farm conditions, was added to the sampling selection. Additionally, ash, protein, lipid, carbohydrate and moisture content, as well as water activity were measured. Finally, a tool in the form of a decision graph that gathered all the interesting data on fiber in this study was developed. This 4-D data first perfectible representation, designed for direct use by

the agro-industry, aimed to assist farmers and stakeholders in the industry to select the best compromise for their byproducts, based on their intended application. In addition to those new scientific insights, the novelty and originality bring by the study is to hypothesis that there is a close link between the content of those two types of fibers, and that the change in mass of one of them is highly dependent of the other one, in the peels but also in the pulp, without identified the biochemical reason in this work. In a context of applied food research, this work also wants to highlight the importance of controlling pre- and post-harvest operations for the valorization of mango byproducts for animal feed applications, as uncontrolled technical itinerary on a large quantity of byproducts can lead to significant variation in fiber composition, while a simple technical choice can favor the content of one or the other.

## 2. Material and methods

### 2.1. Chemicals

All products including the solvents (hexane, ethanol, acetone), acids (sulfuric, nitric, hydrochloric), Kjeldahl tablets, potassium sulphate, copper sulphate, boric acid, α-amylase, protease, ethyl-enedinitrilotetraacetic acid (EDTA), sodium lauryl sulfate, sodium borate, sodium hydrogen phosphate, triethylene glycolethyl-trimethylammonium bromide and standards were bought from Sigma-Aldrich (USA).

### 2.2. Sample harvesting and processing

Fresh Keo Romeat mango was harvested from the Kirirom Food Product at Kampong Speu Province (Latitude: 11° 27′ 11.95″ N / Longitude: 104° 31′ 15.06″ E) in Cambodia during the mango season in May 2024. Fifty kilograms of mango were selected at four different ripening stages. These stages were identified by the visual change of the color of the peel from green to yellow/red and the firmness of the fruits (Rivas-Robles et al., 2024). Simple sugars were estimated to assess maturity, but the selection was made as proposed by this study on visual color assessment. Based on the work cited, the sampled ripening stages were: young mangoes (YM), mangoes between young and ripe (YRM), ripe mangoes (RM) and over-ripe mangoes (ORM) (Fig. 1), with 13 kg per ripening stage which represented around 40 fruits. These four stages of ripening were selected because they are the four main stages that are the most visually noticeable in the ripening of Keo Romeat mangoes in the field, corresponding to known changes in macronutrients (particularly the sugar/acid ratio).

Fresh harvested mangoes of each ripening stage were washed with water, cleaned, and peeled to separate the peel and pulp. Then, mango pulp and peel from each stage were cut by hand into slices of 10–20 mm width and 80–100 mm length and dehydrated using three treatments. The first one was freeze-drying using an alpha LSCbasic freeze dryer (Martin christ, Germany) at –85 °C and around 0.06 mbar for 48 h. As the freeze-dried process does not degrade the fruit, the freeze-dried samples were used as the references for each ripening stage. The operating condition of treatments were selected to mimic drying under real farm-level condition as practiced in Cambodia, therefore taking into account data (i.e. climate, processing) reported several times in other important sectors in the country or more generally in Asia, which have already benefited from the development and implementation of low-tech processes, such as fish farming (Hin et al., 2024a; Hin et al., 2024b; Udomkun et al., 2020). The second treatment consisted of drying using a UNE400 oven at 50 °C for 34 h (Memmert, Germany) to mimic sun drying. The last one was blanching in boiling water for 1 min before the same drying method, as it is conventionally realized in blanching treatments of fruits. Finally, a commercial sample was taken directly from the farm and integrated as the real on-farm sample. This byproduct sample of uncontrolled maturity was dried by conventional solar drying (spread on the ground + dried outdoors for 48 h). After drying, all the
<figure><img src="image_3.png" /><figcaption>Young (YM) -
Light green and
firm texture</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>Between young
and ripe (YRM) -
Dark green and firm texture</figcaption></figure>

<figure><img src="image_5.png" /><figcaption>Ripe (RM) - Yellow
and firm texture</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>Over-ripe (ORM) -
Dark green and soft
texture</figcaption></figure>

<caption>**Fig. 1.** Physical characteristics of mango maturity sampled.</caption>

samples were finely ground with a T-500 A knife grinder (GRT, China) and sieved through 0.5 µm for further analysis. Thereafter, the samples were sent from a Cambodian laboratory (Phnom Penh) to a French one (Montpellier) by cold delivery, kept at –20 °C throughout the entire delivery process. Therefore, the sampling selection consisted of 3 processing methods x 4 ripening stages x 2 fruit parts (peel and pulp) and of the commercial sample. All subsequent analytical measurements of the study were achieved in triplicate. All results were expressed in g·100 g⁻¹ of DM of pulp or peel except the moisture and sugar contents.

## 2.3. Proximal analysis

The residual moisture content was measured using a UNE400 drying oven (Memmert, Germany) at 105 °C for 24 h and the water activity was assessed by a LabTouch-Aw water activity meter (Novasina AG, Switzerland) following the method used by de Medeiros et al. (2022). Ash content was determined according to Akhter et al. (2024) with a muffle furnace L3/11 (Nabertherm, Germany) at 550 °C for 3 h. The lipid content was determined by the Soxhlet methodology (Hewavitharana et al., 2020) using a Soxtec SER148 extractor (Velp Scientifica, Italy) at a temperature of 130 °C for 1 h of immersion phase, 1 h of washing time and 15 min of the evaporation step. Protein content was determined by the Kjeldahl method (Kaur et al., 2025) and the conversion factor used was 6.25. The carbohydrate content was evaluated as the difference between total mass and the sum of moisture, ash, protein, and lipid content.

## 2.4. Insoluble fiber measurement

The fiber content was determined using the Van Soest Method (Corrales et al., 2017; Van Soest, 1978; Van Soest et al., 1991). A precise quantity of homogeneous dry mango peel or pulp (between 0.7 and 1 g) was weighed into F57 macro-porous bags (Ankom Technology, USA). Thereafter, the whole process was carried out in an Ankom200 fiber analyzer (Ankom Technology, USA). The samples were first subjected to consecutive 1 mL·L⁻¹ alpha-amylase maceration for 25 min at 100 °C and > 1000 U·L⁻¹ protease maceration for 15 min at 38 °C. Thereafter, samples were extracted consecutively following Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF) and Acid Detergent Lignin (ADL) official procedures.

## 2.5. Soluble pectin - Alcohol Insoluble Residues (AIR)

AIR was extracted as described by Sudhakar and Maini (2000) and Brat et al. (2003) using boiling ethanol for 1 h under a reflux heating system. The residues were then washed three times with pure ethanol and twice with acetone to remove all traces of lipids, phenols, sugars, etc., and rinsed twice with diethyl ether to facilitate drying at 55 °C overnight. Pectin was extracted from the AIR, using distilled water acidified to pH 1.5 with nitric acid at 90 °C for 45 min. After cooling, the

sample was centrifuged at 20,000 g for 10 min at 20 °C. The supernatant was collected, and the residue re-extracted with 15 mL of acidified distilled water. The supernatants were pooled, and the pectin was precipitated with 2 vol (v/v) of acetone. The emulsion was left to settle overnight at room temperature, filtered and washed twice with acetone before being dried at 55 °C for 14 h.

## 2.6. Statistical analysis

Statistical analyses were carried out using XLSTAT v.2019 (Addinsoft, Paris, France). Analysis of variance using post hoc Tukey's test were conducted with *p* < 0.05 (n = 3 or *n* = 6). The results were presented as a mean “±” standard deviation.

# 3. Results and discussion

## 3.1. Proximate analysis

The moisture content of fresh pulp and peel samples is described in Fig. 2. As it was reported various times in the literature, mango moisture content is known to change during ripening (Appiah et al., 2011; Jospeh & Aworh, 1991). In our case, the moisture content of fresh pulp also significantly decreased during mango ripening between the young mango stage to the last over-ripe stage. The peels were also concerned by this increase, but in a smaller proportion. These moisture changes are linked to the increase in DM during ripening (Kalra & Tandon, 1983). After processing (blanching and drying), dry matter content was similar with a slightly higher value in the dried sample. The means of dry matter in the pulp that were blanched and dried, freeze-dried and dried (n = 12 for each treatment) were 11.70 ± 1.29, 12.78 ± 2.33 and 14.56 ± 0.95 g·100 g⁻¹ respectively with water activity (a<sub>w</sub>) of 0.46 ± 0.01, 0.43 ± 0.01 and 0.44 ± 0.01. This low a<sub>w</sub> means that the dried products were stable regardless of the processing method (Alzamora et al., 2005). After drying, the mean dry matter content of peel (n = 12) was 10.32 ± 0.85, 6.70 ± 0.99, and 10.35 ± 2.27 g·100 g⁻¹ for blanched and dried, freeze-dried, and dried samples respectively associated to a mean a<sub>w</sub> (n = 36) of 0.44 ± 0.08. The water evaporation kinetics of fruit products is complex as it depends on parameters such as moisture diffusivity during drying, thermal conductivity, density of the material, temperature interphases, etc. All of these properties are mainly influenced by the sugar structures and contents, which also constantly change during fruit drying (Karathanos, 1999). Therefore, the lower dry matter of the freeze-dried mango peel was attributed to the sugar structure, which might be altered during hot air drying, for example by polymerization or decomposition, which significantly alters the water retention.

On one hand, sugar content is known to increase during ripening. In our case, it increased by >6.5-fold between the YM to ORM stages. Sugar content was 2.72 ± 0.26 g·100 g⁻¹ of fresh matter for YM, 3.77 ± 0.35 for YRM, 14.36 ± 0.11 for RM and 17.81 ± 0.14 for ORM (n = 3). This increase in simple sugars during fruit ripening is conventional and
<figure><img src="image_7.png" /><figcaption>Fig. 2. Moisture contents of pulp and peel samples at the 4 different ripening stages (ANOVA, Tukey, *p* < 0.05) with ■ for pulp and ☑ for peel.</figcaption></figure>

widely referenced. It is mainly due to the breakdown of starch into simple sugars by amylases during ripening. Then the proportion between simple sugar (mainly sucrose, glucose, fructose) is modulated by the action of other several enzymatic activities such as invertases, sucrose synthase, etc. (Castrillo et al., 1992; Gill et al., 2017). For their part, lipid content significantly decreased during ripening with contents of 3.90 ± 0.24, 2.18 ± 0.42, 1.25 ± 0.12 and 0.73 ± 0.05 g·100 g⁻¹ of DM for YM, YRM, RM and ORM, respectively. This kind of decrease has not been reported in the specific case of mangoes, but has already been observed in other raw materials such as peaches, tomatoes, bananas, etc., and can be generalized to most plant tissues at the end of their growth or ripening. This is linked to the weakening of membranes

during ripening, which contain most of the lipids in fruit as fatty acids, triacylglycerols, phospholipids, sterols, etc., (Izzo et al., 1995). On the other hand, ash and proteins did not change during ripening with a mean between 1.73 ± 0.60 and 2.99 ± 1.26 g·100 g⁻¹ of DM. Protein was reported to be stable during mango ripening, with slight variations (mainly conversion from insoluble to soluble proteins) (Sharaf et al., 1989). Regarding ash, the literature is less clear. The evolution of ash obviously depends on the mineral absorption of the plant and accumulation in the fruit which relies on fruit variety, soil, agronomic conditions, etc. Some authors reported a slight decrease in ash content during mango ripening while other authors showed that it was stable (Geerkens et al., 2015; Tharanathan et al., 2006). None of the processing

**Table 1**

Fiber (hemicellulose, cellulose and lignin), Pectin and Alcohol Insoluble Residue (AIR) contents in g·100 g⁻¹ of dry matter (DM) for mango pulp and peel at each ripening stages and for the three processes of transformation (blanched and dried, freeze-dried and solely dried) – YM = young mango, YRM = mango between young and ripe, RM = ripe mango and ORM = over-ripe mango.

<table><thead><tr><th>Sample type</th><th>Ripening</th><th>Process</th><th>Hemicellulose (g·100 g<sup>-1</sup> DM)</th><th>Cellulose (g·100 g<sup>-1</sup> DM)</th><th>Lignin (g·100 g<sup>-1</sup> DM)</th><th>Total fibers (g·100 g<sup>-1</sup> DM)</th><th>Alcohol Insoluble Residues (g·100 g<sup>-1</sup> DM)</th><th>Pectin (g·100 g<sup>-1</sup> DM)</th></tr></thead><tbody><tr><td rowspan="12">Pulp</td><td>YM</td><td>Blanching and drying</td><td>4.61 ± 0.24</td><td>7.38 ± 0.46</td><td>0.00</td><td>11.99</td><td>43.20 ± 1.27</td><td>22.00 ± 0.90</td></tr><tr><td>YM</td><td>Freeze-drying</td><td>3.70 ± 0.30</td><td>5.08 ± 0.03</td><td>0.00</td><td>8.78</td><td>60.21 ± 6.31</td><td>29.13 ± 1.38</td></tr><tr><td>YM</td><td>Drying</td><td>2.71 ± 0.17</td><td>5.54 ± 0.02</td><td>0.00</td><td>8.25</td><td>56.80 ± 0.06</td><td>28.85 ± 0.82</td></tr><tr><td>YRM</td><td>Blanching and drying</td><td>5.18 ± 0.22</td><td>6.39 ± 0.64</td><td>0.00</td><td>11.57</td><td>42.28 ± 1.03</td><td>21.99 ± 0.50</td></tr><tr><td>YRM</td><td>Freeze-drying</td><td>2.87 ± 0.17</td><td>4.00 ± 0.05</td><td>0.00</td><td>6.87</td><td>60.17 ± 0.31</td><td>26.54 ± 0.60</td></tr><tr><td>YRM</td><td>Drying</td><td>3.56 ± 0.08</td><td>3.54 ± 0.04</td><td>0.00</td><td>7.10</td><td>58.86 ± 0.16</td><td>27.98 ± 1.00</td></tr><tr><td>RM</td><td>Blanching and drying</td><td>2.10 ± 0.26</td><td>3.47 ± 0.03</td><td>0.00</td><td>5.57</td><td>69.51 ± 1.03</td><td>39.38 ± 1.00</td></tr><tr><td>RM</td><td>Freeze-drying</td><td>0.97 ± 0.00</td><td>1.25 ± 0.07</td><td>0.00</td><td>2.22</td><td>79.18 ± 0.86</td><td>40.24 ± 0.96</td></tr><tr><td>RM</td><td>Drying</td><td>1.13 ± 0.06</td><td>1.37 ± 0.04</td><td>0.00</td><td>2.50</td><td>78.44 ± 0.63</td><td>42.81 ± 0.86</td></tr><tr><td>ORM</td><td>Blanching and drying</td><td>1.05 ± 0.10</td><td>2.97 ± 0.16</td><td>0.00</td><td>4.02</td><td>81.61 ± 0.53</td><td>58.99 ± 0.20</td></tr><tr><td>ORM</td><td>Freeze-drying</td><td>0.75 ± 0.07</td><td>1.80 ± 0.12</td><td>0.00</td><td>2.55</td><td>82.22 ± 1.84</td><td>57.37 ± 0.60</td></tr><tr><td>ORM</td><td>Drying</td><td>1.44 ± 0.02</td><td>1.74 ± 0.05</td><td>0.00</td><td>3.18</td><td>75.63 ± 3.97</td><td>53.76 ± 0.40</td></tr><tr><td rowspan="12">Peel</td><td>YM</td><td>Blanching and drying</td><td>8.89 ± 0.69</td><td>12.86 ± 0.51</td><td>5.07 ± 0.01</td><td>26.82</td><td>29.83 ± 0.15</td><td>19.25 ± 0.18</td></tr><tr><td>YM</td><td>Freeze-drying</td><td>8.34 ± 0.15</td><td>10.61 ± 0.74</td><td>4.65 ± 0.34</td><td>23.60</td><td>33.73 ± 0.60</td><td>21.90 ± 0.86</td></tr><tr><td>YM</td><td>Drying</td><td>8.01 ± 0.26</td><td>10.11 ± 1.29</td><td>6.05 ± 1.09</td><td>24.17</td><td>30.44 ± 0.77</td><td>20.31 ± 1.01</td></tr><tr><td>YRM</td><td>Blanching and drying</td><td>9.98 ± 0.80</td><td>13.81 ± 0.06</td><td>6.57 ± 0.52</td><td>30.36</td><td>28.25 ± 9.66</td><td>19.98 ± 0.89</td></tr><tr><td>YRM</td><td>Freeze-drying</td><td>7.66 ± 0.94</td><td>9.07 ± 0.27</td><td>9.22 ± 1.10</td><td>25.95</td><td>29.57 ± 0.02</td><td>20.46 ± 0.55</td></tr><tr><td>YRM</td><td>Drying</td><td>7.13 ± 0.32</td><td>10.17 ± 0.03</td><td>4.14 ± 0.02</td><td>21.43</td><td>35.26 ± 0.09</td><td>22.95 ± 0.51</td></tr><tr><td>RM</td><td>Blanching and drying</td><td>3.51 ± 0.25</td><td>7.80 ± 1.43</td><td>2.50 ± 0.40</td><td>13.81</td><td>43.97 ± 0.49</td><td>27.20 ± 1.01</td></tr><tr><td>RM</td><td>Freeze-drying</td><td>3.12 ± 0.59</td><td>7.40 ± 0.30</td><td>2.46 ± 0.24</td><td>12.98</td><td>52.26 ± 0.29</td><td>33.55 ± 0.53</td></tr><tr><td>RM</td><td>Drying</td><td>3.15 ± 0.24</td><td>6.69 ± 0.19</td><td>2.55 ± 0.03</td><td>12.39</td><td>54.44 ± 0.38</td><td>33.77 ± 1.49</td></tr><tr><td>ORM</td><td>Blanching and drying</td><td>5.45 ± 0.53</td><td>9.30 ± 0.19</td><td>2.77 ± 0.05</td><td>17.52</td><td>51.14 ± 1.13</td><td>34.46 ± 1.13</td></tr><tr><td>ORM</td><td>Freeze-drying</td><td>5.05 ± 0.11</td><td>9.23 ± 0.38</td><td>3.44 ± 0.19</td><td>17.72</td><td>55.86 ± 1.91</td><td>36.59 ± 1.14</td></tr><tr><td>ORM</td><td>Drying</td><td>3.51 ± 0.19</td><td>8.17 ± 0.85</td><td>2.62 ± 0.48</td><td>14.30</td><td>55.25 ± 4.58</td><td>37.03 ± 0.59</td></tr><tr><td rowspan="3">Industrial</td><td>Sun drying</td><td>3.66 ± 0.31</td><td>12.03 ± 1.69</td><td>5.39 ± 1.89</td><td>21.08</td><td>47.66 ± 3.69</td><td>32.28 ± 0.42</td></tr><tr><td>Sun drying</td><td>3.57 ± 0.36</td><td>10.00 ± 0.18</td><td>4.37 ± 1.28</td><td>17.94</td><td>53.00 ± 0.61</td><td>35.38 ± 0.22</td></tr><tr><td>Sun drying</td><td>3.81 ± 0.17</td><td>12.99 ± 3.25</td><td>4.45 ± 0.49</td><td>21.25</td><td>54.65 ± 0.39</td><td>36.27 ± 0.27</td></tr></tbody></table>
treatments applied resulted in significant changes in the macronutrient contents of mango pulp or peel. For instance, average ash content (n = 12) in pulp was 1.83 ± 0.38, 2.23 ± 0.75, and 1.96 ± 0.65 g·100 g⁻¹ of DM for blanched and dried, freeze-dried and dried samples, respectively. Similarly, protein content was 3.98 ± 0.38, 3.09 ± 0.96, and 3.21 ± 0.55 g·100 g⁻¹ of DM for the same treatments. In the case of peel, no significant differences were observed among the processing treatments in terms of ash, lipid, protein or carbohydrate contents. The mean values (n = 36) were 3.08 ± 1.28 for ash, 1.85 ± 0.36 for lipids, 2.76 ± 0.76 for proteins, and 83.36 ± 2.69 g·100 g⁻¹ of DM for carbohydrates.

## 3.2. Insoluble fiber changes

Table 1 describes, among others, the hemicellulose, cellulose, and lignin contents of mango pulp and peel for the 4 ripening stages, as well as of the industrial samples, following three processing treatments: blanching and drying, freeze-drying, and drying. Total fiber content was calculated as the sum of the three components mentioned. Regarding mango peel, a simple means comparison (Table 2) using ANOVA followed by Tukey's test (p < 0.05) reveals that the ripening stage is the main factor influencing fiber content. The earlier the ripening stage, the higher the fiber content. For instance, peel from the young mangoes contained on average 8.4 g·100 g⁻¹ of DM hemicellulose, 11.2 g·100 g⁻¹ of DM cellulose, and 5.3 g·100 g⁻¹ of DM lignin (totaling 24.9 g·100 g⁻¹ of DM total fiber), while peel from ripe mangoes presented only 4.7 g·100 g⁻¹ of DM hemicellulose, 8.9 g·100 g⁻¹ of DM cellulose, and 2.9 g·100 g⁻¹ of DM lignin (a total of 16.5 g·100 g⁻¹ of DM fiber). The fiber content of industrially-processed mango peel samples was generally lower in fiber content than that of the YM stage, except for cellulose where values were comparable. Therefore, to maximize the fiber content, selecting mangoes at an early ripening stage is recommended. The loss in hemicellulose and cellulose during ripening might be due to enzymatic activities (El-Zoghbi, 1994). Lignin is different since its degradation during ripening is uncommon, and its accumulation in the fruit generally stops at some point during fruit growth (Zhang et al., 2020). However, specific articles on lignin explain that lignin depolymerization can occur in fruit during ripening or processing, depending on the quality of the components that make up the cell wall (Assis et al., 2001; Castro & Morales-Quintana, 2019). The measurement of lignin can also be affected by other compounds such as pectin Lanes et al. (2016). Finally, the differences in fiber and pectin between samples processed by drying (with or without blanching) and freeze-dried (used as the reference) were calculated using Eq. (1) and are reported in Table 3. This simple equation underlines the deviation of each sample from the reference in terms of individual fiber components and pectin.

$$ \Delta_{\text{processing}} = \left( \frac{\text{Content}_{\text{process}} - \text{Content}_{\text{freeze-dried}}}{\text{Content}_{\text{freeze-dried}}} \right) * 100 \quad (1) $$

<caption>**Table 2**</caption>

Means comparison of each fiber category (n = 9), alcohol insoluble residue and pectin content (n = 9) based on the 4 ripening stages in mango peel and the industrial sample. YM = young mango, YRM = mango between young and ripe, RM = ripe mango and ORM = over-ripe mango.

<table><thead><tr><th>Ripening</th><th>Hemicellulose (g·100 g<sup>-1</sup> DM)</th><th>Cellulose (g·100 g<sup>-1</sup> DM)</th><th>Lignin (g·100 g<sup>-1</sup> DM)</th><th>Alcohol Insoluble Residues (g·100 g<sup>-1</sup> DM)</th><th>Pectin (g·100 g<sup>-1</sup> DM)</th></tr></thead><tbody><tr><td>YM</td><td>8.41<sup>a</sup></td><td>11.19<sup>a</sup></td><td>5.26<sup>b</sup></td><td>31.33<sup>b</sup></td><td>20.76<sup>c</sup></td></tr><tr><td>YRM</td><td>8.24<sup>a</sup></td><td>11.02<sup>a</sup></td><td>6.64<sup>a</sup></td><td>31.03<sup>b</sup></td><td>21.26<sup>c</sup></td></tr><tr><td>RM</td><td>4.67<sup>b</sup></td><td>8.90<sup>b</sup></td><td>2.94<sup>c</sup></td><td>50.22<sup>a</sup></td><td>31.68<sup>b</sup></td></tr><tr><td>ORM</td><td>3.26<sup>c</sup></td><td>7.30<sup>b</sup></td><td>2.50<sup>c</sup></td><td>54.08<sup>a</sup></td><td>36.28<sup>a</sup></td></tr><tr><td>Industrial</td><td>3.68<sup>c</sup></td><td>11.67<sup>a</sup></td><td>4.73<sup>b</sup></td><td>51.77<sup>a</sup></td><td>34.71<sup>ab</sup></td></tr></tbody></table>

Different letters in a column expressed the significant difference between value groups by means of ANOVA-Tukey test (p < 0.05).

The greater the Δ<sub>processing</sub> value, the more the sample differs from the freeze-dried reference, expressed as a percentage. A positive Δ<sub>processing</sub> indicates a higher fiber content than the freeze-dried sample, a negative value indicates a lower content. For hemicellulose and cellulose, the results showed that blanching prior to drying helped preserve, or even enhance, total fiber content. This impact on insoluble fiber was not reported on mangoes but is known for other vegetables such as peas, carrots, cauliflower, broccoli, cabbage, potatoes, etc. It was attributed to the thermal resistance of insoluble fiber, the inactivation of enzymes and the release of insoluble fiber due to the breakdown of cell wall structure (Akter et al., 2010; Puupponen-Pimiä et al., 2003). In contrast, the impact of drying on lignin was less conclusive, probably because the mechanisms leading to its degradation and/or modification are less understood and dependent on the structural condition of the raw material of the cell walls, which was not considered in this study. Based on these results, blanching is recommending as a pre-treatment before drying to help preserve fiber content. Regarding mango pulp, the results confirmed that ripening stage is the most influential factor to achieve higher fiber content (Fig. 3). Additionally, the positive effects of blanching observed in peel samples were also confirmed in pulp (Table 3), in which the blanching step significantly improved hemicellulose and cellulose contents but always with a lower impact than ripening stage.

## 3.3. Soluble pectin changes

Table 1 presents the results for soluble pectin and Alcohol Insoluble Residues (AIR) in mango peel and pulp. AIR described the mass of material insoluble in alcohol, a common purification step in pectin extraction. However, AIR contain a variety of compounds, with pectin being only one component. Notably, in the case of Keo Romeat mango peel and pulp, increases or decreases in AIR corresponded to similar changes in water soluble pectin content. This important point suggested that non-pectic or insoluble substances within AIR remained relatively stable. Consequently, the following analysis focuses on water soluble pectin content.

As shown in Table 2 for peel and Fig. 4 for pulp, a similar comparison to that performed for fiber revealed that ripening stage is again the primary factor influencing water soluble pectin contents. Indeed, the soluble pectin contents measured in this study increased with the ripening stage of mango. This increase makes sense, as the decrease in fruit firmness has already been associated with the degradation and loss of cell wall adhesion, the increase in soluble pectin, and a loss of insoluble fiber (Lewis, 1978; Malis-Arad et al., 1983). For example, in the case of mango, soluble pectin increased from 1.9 to 9.6 g·100 g⁻¹ (fresh pulp), or from 1.8 to 11.9 g·100 g⁻¹ between unripe and ripe fruit (Medlicott & Jeger, 1987). This increase was associated with a loss of firmness and the enzymatic degradation of insoluble fibers. While this hypothesis has been confirmed for certain specific fruits and varieties, it is always underlined that these phenomena are dependent on the raw material and its composition. In the case of this study, the soluble pectin in Keo Romeat mango peels from Cambodia increased significantly by 67% from the initial content, rising from 20.76 to 34.71 g·100 g⁻¹ of DM, while it increased from 26.9 to 56.6 g·100 g⁻¹ of pulp DM for the same samples. To achieve high soluble pectin content in both pulp and peel, it is therefore advised to use ripe or over-ripe mangoes. Table 3 indicated that the transformation process also affects pectin content. In most cases, processing led to pectin degradation, probably because of pectin depolymerization caused by the heat intake and pH conditions (Fraeye et al., 2007). Blanching with its higher heat input, contrary to its effect on insoluble fibers, did not help to maintain the pectin content observed in the freeze-dried reference samples. Therefore, blanching allows the liberation of more insoluble fibers, by degrading the condition of plant cells, but also it accelerates the depolymerization of soluble pectin.

Mastering ripening is key to controlling the insoluble and soluble fibers of Keo Romeat mango byproducts, as the transformation process
<caption>**Table 3**</caption>

Changes (Δ<sub>processing</sub>) of dried samples with and without blanching, for the 3 fiber categories, the alcohol insoluble residue (AIR) and the pectin contents in mango peel and pulp. YM = young mango, YRM = mango between young and ripe, RM = ripe mango and ORM = over-ripe mango.

<table><thead><tr><th rowspan="2">Sample</th><th rowspan="2">Ripening</th><th rowspan="2">Process</th><th colspan="5">Δ<sub>Processing</sub></th></tr><tr><th>Hemicellulose (%)</th><th>Cellulose (%)</th><th>Lignin (%)</th><th>Alcohol Insoluble Residues (%)</th><th>Pectin (%)</th></tr></thead><tbody><tr><td rowspan="7">Peels</td><td>YM</td><td>Blanching and drying</td><td>6.6</td><td>21.2</td><td>9.0</td><td>-11.56</td><td>-12.10</td></tr><tr><td>YM</td><td>Drying</td><td>-4.0</td><td>-4.7</td><td>30.1</td><td>-9.75</td><td>-7.26</td></tr><tr><td>YRM</td><td>Blanching and drying</td><td>30.3</td><td>52.3</td><td>-28.7</td><td>-4.46</td><td>-2.35</td></tr><tr><td>YRM</td><td>Drying</td><td>-6.9</td><td>12.1</td><td>-55.1</td><td>19.24</td><td>12.17</td></tr><tr><td>RM</td><td>Blanching and drying</td><td>7.9</td><td>0.8</td><td>-19.5</td><td>-15.86</td><td>-18.93</td></tr><tr><td>RM</td><td>Drying</td><td>-30.5</td><td>-11.5</td><td>-23.8</td><td>4.17</td><td>0.66</td></tr><tr><td>ORM</td><td>Blanching and drying</td><td>12.5</td><td>5.4</td><td>1.6</td><td>-8.45</td><td>-5.82</td></tr><tr><td rowspan="7">Pulps</td><td>YM</td><td>Drying</td><td>1.0</td><td>-9.6</td><td>3.7</td><td>-1.09</td><td>1.20</td></tr><tr><td>YM</td><td>Blanching and drying</td><td>24.6</td><td>45.3</td><td>na</td><td>-28.25</td><td>-24.48</td></tr><tr><td>YM</td><td>Drying</td><td>-26.8</td><td>9.1</td><td>na</td><td>-5.66</td><td>-0.96</td></tr><tr><td>YRM</td><td>Blanching and drying</td><td>80.5</td><td>59.8</td><td>na</td><td>-29.73</td><td>-17.14</td></tr><tr><td>YRM</td><td>Drying</td><td>24.0</td><td>-11.5</td><td>na</td><td>-2.18</td><td>5.43</td></tr><tr><td>RM</td><td>Blanching and drying</td><td>116.5</td><td>177.6</td><td>na</td><td>-12.21</td><td>-2.14</td></tr><tr><td>RM</td><td>Drying</td><td>16.5</td><td>9.6</td><td>na</td><td>-0.93</td><td>6.39</td></tr><tr><td rowspan="2">ORM</td><td>ORM</td><td>Blanching and drying</td><td>40.0</td><td>65.0</td><td>na</td><td>-0.74</td><td>2.82</td></tr><tr><td>ORM</td><td>Drying</td><td>47.9</td><td>-3.4</td><td>na</td><td>-8.02</td><td>-6.29</td></tr></tbody></table>

Na = Not applicable.

<figure><img src="image_8.png" /><figcaption>**Fig. 3.** Hemicellulose and cellulose means for mango pulp at 4 ripening stages. Different letters in the same fiber category designated a significant difference between ripening stage (ANOVA, Tukey, *p* < 0.05) with ■■■ for mango between young and ripe (YRM), ■■ for young mango (YM), ■ for ripe mango (RM), ■■■ for over-ripe mango (ORM).</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>**Fig. 4.** Pectin and AIR (alcohol insoluble residue) means for the mango pulp at 4 ripening stages. Different letters in the same fiber category designated a significant difference between ripening stage (ANOVA, Tukey, *p* < 0.05) with ■■■ for mango between young and ripe (YRM), ■■ for young mango (YM), for ripe mango (RM), ■■■ for over-ripe mango (ORM).</figcaption></figure>

used to stabilize them influences fiber content less. Depending on the international market targeted by the producer, the specifications for
animal feed require varying amounts of insoluble fiber, and are more or less restrictive on the composition (soluble fiber, macronutrients, etc.). These results indicated that there is a strong link between soluble and insoluble fiber content, with one content having a "leveraging" effect on the other, which is worth exploring further.

### 3.4. Comparison of pectin and fiber content

Pectin and fiber contents showed contrasting trends. To illustrate this, total fiber content was plotted against pectin content for each raw material (Fig. 5). This representation clearly demonstrated that maximizing both pectin and fiber simultaneously is not feasible: total fiber increased as pectin content decreased, and vice-versa. The correlation coefficients R² up to 0.7 shows a valuable negative correlation between the content of each type of fiber. It appears that during the ripening of Keo Romeat mango, soluble pectin gradually increases until full ripeness is reached. In the literature, this increase can be associated with a decrease in insoluble fibers, particularly protopectin. Such high variations in soluble pectin can only come from structurally similar compounds, i.e., their best-known precursor: protopectin, through the action of protopectinase (Sakamoto et al., 1995). The Van Soest method, which allows fibers to be split into NDF, ADF, and ADL, is effective, accurate, and repeatable, but it is also known to be sensitive and affected by the presence of other components, particularly pectin (Van Soest et al. 1991). Fruits rich in pectic substances are known to interfere with the values obtained for NDF, ADF, and in some cases ADL (de Carvalho et al., 2006; Lanes et al., 2016). This implies that the contamination by pectic substances forms physical networks that limit the interaction of the detergent at each extraction phase (Cassida et al., 2007). The correlation conducted in this latest study also suggested that in the case of fruits rich in pectic substances, there are other compounds that interfere with measurements, although these have not yet been identified. Thus, it could be that the conversion of insoluble protopectin into soluble pectin also contributed to the drop in fiber observed for all categories of fiber.

As a result, several phenomena occur simultaneously during ripening and processing: 1. An increase in mass of soluble pectin due to the breakdown of other pectic substances, that was not characterized in this study and so that structure is unknown. 2. A decrease in total fiber content due to the action of endogenous cellulases and hemicellulases. 3. A drop in the fiber values measured by the Van Soest method (the reference protocol for fiber analysis in animal feed), linked to the degradation of pectic substances and fiber degradation. These phenomena are associated with high enzyme activity (pectinase, pectin methylesterase, polygalacturonase, β-galactosidase, cellulases, protopectinases), which has already been reported in multiple studies (Abu-Sarra & Abu-Goukh, 1992; Cárdenas-Pérez et al., 2018; Jamsazzadeh Kermani et al., 2015; Sakamoto et al., 1995). Finally, 4. blanching results in the release of a few fibers from the cell wall, and probably inhibits some of the enzyme activities, but also degrades part of the soluble pectin formed. However,

even if these processing methods have a significant impact, the impact remains limited compared to that of ripening stage.

Depending on the objective of the rural agro-industry, three strategies for optimizing mango byproduct quality can be considered: 1. maximize fiber content in peel and pulp, and accept a lower pectin content; 2. maximize pectin content in mango peel and pulp with a lower fiber content; 3. find a compromise, achieving moderate levels of both pectin and fiber. Although this representation highlighted scientific insights, particularly the observation that pectin quantification, which is faster, cheaper and easier than fiber analysis, may serve as a proxy for estimating total fiber, it did not allow the best conditions to be determined.

To address this, an example of a 4-D data representation (Fig. 6) was developed as a practical tool to replace a technical sheet for use in the field. It represented the total fiber content of the peel (Y axis) vs. the pectin content (X axis) plot in Fig. 5, nuanced by the processing methods (including freeze-drying as a reference) (Z axis). Moreover, the ripening stage modality was added to help the reader. This data representation, designed as an initial approach to be further developed and improved, was created for the agribusiness partner in the article, for the pulp, the peel, and a mix of both. It allows the optimal conditions to be identified based on desired final quality. For instance, on the one hand, if the rural producer wishes to export Keo Romeat peel for animal feed with a high content in total fiber, the red circle indicates the conditions that yielded the highest fiber. In this case, the highest amount is up to 22 % of the dry mango, however selecting this points will reduce the pectin contents below 20 % of DM. Therefore, he should select the young mango peel, and it is clear that blanching before drying will help to get even more fiber (on the figure blanched and dried on the right sample have the highest content of total fiber around between 28 and 30 % of DM). However, a simple drying process can also lead to a high fiber content, but with approximately 15 % less fiber than the blanching/drying combination. The final decision can obviously be made considering the technological capacities of the mango producer, and the cost of the product to be sold. On the other hand, if the producer wants mango peel that is rich in pectin, for example as a gelling agent or to have better nutritional quality for animal feed, the blue circle highlights conditions favoring this option. In this case, over ripe mangoes are recommended, but it will also minimize the content in insoluble fibers. In this case of Keo Romeat mango, this led to dry mango peel with >36 % of pectin while the total fiber was reduced below 16 %. Since processing method has minimal effect, as can be seen on the figure (dark green dots), simple drying is sufficient. The green circle represents industrial samples with unknown ripening stages. These showed intermediate values, with lower pectin content (26–28 % DM) and roughly half the fiber content (14–18 % DM) compared to young mangoes. A third choice would be to mix all the mango postharvest losses, but in this case, care should be taken to avoid upsetting the balance by adding too much of one ripening stage or another. Interestingly, the intermediate ripening stages are not located

<figure><img src="image_10.png" /><figcaption>Fig. 5. Plot of total fiber vs pectin contents for pulp (black dots) and peel (grey dots).</figcaption></figure>
<figure><img src="image_11.png" /><figcaption>Fig. 6. 4-Dimensional representation of peel pectin and total fiber vs the three processing methods (blanching and drying, drying, and freeze-drying) and the four ripening stages (young, between young and ripe, ripe and over-ripe).</figcaption></figure>

between the two stages, but are rather close to the extremes, which re-
inforces the importance of controlling the stage of ripeness using
methods other than the strategy based on skin color. The use or non-use
of blanching should always be considered in relation to its deployment
cost (if not owned by the stockholder) or operating cost, compared to the
selling price of the product obtained. This simple data representation
allows the scientific content of the study to be simplified so that readers
without specific scientific knowledge can understand the choices to be
made based on the product quality they desire, thereby guiding their
practical choices. It should be complemented by more data to be of
greater interest, more comprehensive in terms of the choices and raw
materials available, and above all, generic to several agro-industries.
The numerical values depend on the raw material (variety, geograph-
ical area, etc.), so they cannot be generalized and are specific to this
producer and this Keo Romeat production. Thus, the representation
could be improved by integrating more data in order to present a se-
lection based on the average percentage reduction or increase in fiber for
several varieties or geographical areas. However, it at least gives a clear
idea in this specific context and represents an interesting strategy for
implementing scientific data at the heart of southern rural farms.

4. Conclusions

These data, generated as part of applied research to support and
assist a Cambodian agribusiness, have highlighted and clarified con-
flicting data in the literature on the evolution of soluble and insoluble
fibers during the ripening of Keo Romeat mangoes. It appears that when
using the byproduct for animal feed, it is impossible to maximize both
the soluble pectin and insoluble fiber content. Due to enzymatic activ-
ities, limitations in the standardized method for quantifying fiber, and
the significant softening of this mango during ripening, there is a sig-
nificant variation in fiber content in both the peel and pulp. In the pulp,
soluble pectin increases by 110.5 % while total fiber decreases by 65.1

% During ripening, in the skin these values are 67.1 % and 19.2 %, respectively. The good linear anti-correlation established between the evolution of the two types of fiber (R² ≈ 0.7) demonstrates a particularly tenuous link between their concentrations. A tool was developed by gathering scientific data into 4-D representation, designed to be accessible to industrial operators and farmers, even without extended knowledge of food science. However, this 4-D data representation should be improved in order to add genericity to the tool and to make it available and adaptable for more decision-makers, for example by the rationalization of values to general proportion of increase/decrease. Another possibility can be to replace the ripening stage by a number of ripening days to reach a maturation kinetic, or by a ratio sugar/acid to define the ripening stage more clearly. Although, the current analysis only includes fiber and pectin contents, incorporating additional factors such as yield, other composition attributes, or the ease of peeling could further refine the tool and make it commercially relevant. Finally, the biochemical and mechanistic explanations behind these variations have not been proven. It would be interesting to understand precisely what happens in Keo Romeat mangoes by measuring the enzymatic activities and soluble and insoluble fiber structure (including galacturonic acid and acetylation measurement) specific to this matrix.

Funding

This study was financed by the Sustainable Wildlife Management Program funded by the European Union.

Ethics

No humans or animals was involved in this study.
Declaration of generative ai in scientific writing

Authors did not use AI in the submission.

CRediT authorship contribution statement

**Adrien Servent:** Writing - review & editing, Writing - original draft, Visualization, Validation, Supervision, Software, Resources, Project administration, Methodology, Investigation, Funding acquisition, Formal analysis, Data curation, Conceptualization. **Marvin Soto:** Writing - review & editing, Writing - original draft. **Tina Julien:** Methodology, Investigation, Formal analysis, Data curation. **Sela Cham:** Resources, Methodology, Investigation, Formal analysis. **Savery Yon:** Resources, Methodology, Investigation, Formal analysis. **Chanvorleak Phat:** Resources, Methodology, Investigation, Formal analysis, Data curation. **Elen Morm:** Writing - review & editing, Visualization, Validation, Supervision, Resources, Project administration, Methodology, Investigation, Funding acquisition, Formal analysis, Data curation, Conceptualization.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

The authors would like to express gratitude to the Cambodia Australia Partnership for Resilient Economic Development (CAPRED), Luc Pignolet from CIRAD, Royal Trust Trading Co., Ltd, Kirirom and Food Production (K.F.P) Co., Ltd.

Data availability

Data will be made available on request.

References

Abdul Aziz, N. A., Wong, L. M., Bhat, R., & Cheng, L. H (2012). Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var. Chokanan) in terms of chemical composition, antioxidant compounds and functional properties. *Journal of the Science of Food and Agriculture, 92*(3), 557-563.

Abu-Sarra, A. F., & Abu-Goukh, A. A. (1992). Changes in pectinesterase, polygalacturonase and cellulase activity during mango fruit ripening. *Journal of Horticultural Science, 67*(4), 561-568. https://doi.org/10.1080/00221589.1992.11516284

Ajila, C. M., & Prasada Rao, U. J. S. (2013). Mango peel dietary fibre: Composition and associated bound phenolics. *Journal of Functional Foods, 5*(1), 444-450. https://doi.org/10.1016/j.jff.2012.11.017

Akhter, M. J., Sarkar, S., Rayhanujjaman, M., Kabir, M. S., & Hosain, M. M. (2024). Characterization of mango seed kernel starch: Extraction and analysis. *Food Chemistry Advances, 5*, Article 100806. https://doi.org/10.1016/j.focha.2024.100806

Akinlolu-Ojo, T., Nwanna, E. E., & Badejo, A. A. (2022). Physicochemical constituents and anti-oxidative properties of ripening hog plum (Spondias Mombin) fruits and the quality attributes of jam produced from the fruits. *Measurement: Food, 7*, Article 100037. https://doi.org/10.1016/j.meadoo.2022.100037

Akter, M. S., Ahmed, M., & Eun, J.-B. (2010). Effect of blanching and drying temperatures on the physicochemical characteristics, dietary fiber composition and antioxidant-related parameters of dried persimmons peel powder. *International Journal of Food Sciences and Nutrition, 61*(7), 702-712. https://doi.org/10.3109/09637481003757852

Alzamora, S. M., Guerrero, S. N., López-Malo, A., Welti-Chanes, J., Palou, E., Argaiz, A., & Tapia, M. S. (2005). 19 - Combined preservation techniques for fresh fruit. Ed. In W. Jongen (Ed.), *Improving the safety of fresh fruit and vegetables* (pp. 599-630). Woodhead Publishing. https://doi.org/10.1533/9781845690243.3.599

Appiah, F., Patrick, K., & Idun, I. (2011). Effect of ripening stage on composition, sensory qualities and acceptability of keitt mango (mangifera indica L.) chips. *African Journal of Food, Agriculture, Nutrition and Development, 11*, 5096-5109. https://doi.org/10.4314/ajfand.v11i5.70439

Assis, J. S., Maldonado, R., Muñoz, T., Escribano, M. A. I., & Merodio, C. (2001). Effect of high carbon dioxide concentration on PAL activity and phenolic contents in ripening cherimoya fruit. *Postharvest Biology and Technology, 23*(1), 33-39. https://doi.org/10.1016/S0925-5214(01)00100-4

Brat, P., Rega, B., Alter, P., Reynes, M., & Brillouet, J.-M. (2003). Distribution of volatile compounds in the pulp, cloud, and serum of freshly squeezed orange juice. *J Agric Food Chem, 51*(11), 3442-3447. https://doi.org/10.1021/jf026226y

Cárdenas-Pérez, S., Chanona-Pérez, J. J., Güemes-Vera, N., Cybulsa, J., Szymanska-Chargot, M., Chylinska, M., & ...Dzunek, A. (2018). Structural, mechanical and enzymatic study of pectin and cellulose during mango ripening. *Carbohydrate Polymers, 196*, 313-321. https://doi.org/10.1016/j.carpol.2018.05.044

Cassida, K. A., Turner, K. E., Foster, J. G., & Hesterman, O. B. (2007). Comparison of detergent fiber analysis methods for forages high in pectin. *Animal Feed Science and Technology, 135*(3), 283-295. https://doi.org/10.1016/j.anifeedsci.2006.07.004

Castrillo, M., Kruger, N. J., & Whatley, F. R. (1992). Sucrose metabolism in mango fruit during ripening. *Plant Science, 84*(1), 45-51. https://doi.org/10.1016/0168-9452 (92)90206-2

Castro, R. I., & Morales-Quintana, L. (2019). Study of the cell wall components produced during different ripening stages through thermogravimetric analysis. *Cellulose (London, England), 26*(5), 3009-3020. https://doi.org/10.1007/s10570-019-02305-3

Chin, L., Servent, A., Hor, S., Mith, H., & Bugaud, C. (2024). Predictive models for estimating the sugar content and organic acids in processed mangoes based on the initial content. *International Journal of Food Science and Technology, 59*(12), 9547-9558. https://doi.org/10.1111/ijfs.17604

Corrales, C. V., Fliedel, G., Perez, A. M., Servent, A., Prades, A., Dornier, M., ... Vaillant, F. (2017). Physicochemical characterization of jicaro seeds (Crestencea alata H.B.K.): A novel protein and oleaginous seed. *Journal of Food Composition and Analysis, 56*, 84-92. https://doi.org/10.1016/j.jfca.2016.11.007

de Carvalho, G. G. P., de Paiva Fernandes, F.É., & Pires, A. J. V. (2006). Métodos de determinação dos teores de amido e pectina em alimentos para animais. *REDVET. Revista Electrónica de Veterinaria, 7*(1), 1-12.

de Medeiros, R. A. B., da Silva Júnior, E. V., Barros, Z. M. P., da Silva, J. H. F., Brandão, S. C. R., & Azoubel, P. M. (2022). Convective drying of mango enriched with phenolic compounds from grape residue flour under different impregnation methods. *Food Research International, 158*, Article 111539. https://doi.org/10.1016/j.foodres.2022.111539

El-Zogbi, M. (1994). Biochemical changes in some tropical fruits during ripening. *Food Chemistry, 49*(1), 33-37. https://doi.org/10.1016/0308-8146(94)90229-1

European-Commission. (2025). EU entry conditions for live animals & animal products. https://food.ec.europa.eu/horizontal-topics/international-affairs/eu-entry-conditions/live-animals-animal-products_en.

FDA. (2025). Exporting - animal feed and animal drugs. https://www.fda.gov/animal-veterinary/import-exports/exporting-animal-feed-and-animal-drugs

Fraeye, I., De Roeck, A., Duvetter, T., Verlent, I., Hendrickx, M., & Van Loey, A. (2007). Influence of pectin properties and processing conditions on thermal pectin degradation. *Food Chemistry, 105*(2), 555-563. https://doi.org/10.1016/j.foodchem.2007.04.009

García-Maecha, M., Soto-Valdez, H., Carvajal-Millan, E., Madera-Santana, T. J., Lomelí-Ramírez, M. G., & Colín-Chávez, C. (2023). Bioactive compounds in extracts from the agro-industrial waste of Mango. *Molecules (Basel, Switzerland), 28*(1), 458.

Geerkens, C. H., Nagel, A., Just, K. M., Miller-Rostek, P., Kammerer, D. R., Schweiggert, R. M., & Carle, R. (2015). Mango pectin quality as influenced by cultivar, ripeness, peel particle size, blanching, drying, and irradiation. *Food Hydrocolloids, 51*, 241-251. https://doi.org/10.1016/j.foohyd.2015.05.022

Gill, P. P., Jawandha, S. K., Kaur, N., & Singh, N. (2017). Physico-chemical changes during progressive ripening of mango (Mangifera indica L.) cv. Dashehari under different temperature regimes. *Journal of Food Science and Technology, 54*(7), 1964-1970. https://doi.org/10.1007/s13197-017-2632-6

Hewavitharana, G. G., Perera, D. N., Navaratne, S. B., & Wickramasinghe, I. (2020). Extraction methods of fat from food samples and preparation of fatty acid methyl esters for gas chromatography: A review. *Arabian Journal of Chemistry, 13*(8), 6865-6875. https://doi.org/10.1016/j.arabjc.2020.06.039

Hin, L., Buntong, B., Mean, C. M., Chhoem, C., & Prasad, P. V. V. (2024a). Impacts of using solar dryers on socio-economic conditions of dried fish processors in Cambodia. *Sustainability, 16*(5), 2130. https://www.mdpi.com/2071-1050/16/5/2130

Hin, L., Mean, C. M., Kim, M. C., Chhoem, C., Bunthong, B., Lor, L., ... Prasad, P. V. V. (2024b). Development and performance assessment of sensor-mounted solar dryer for micro-climatic modeling and optimization of dried fish quality in Cambodia. *Clean Technologies, 6*(3), 954-972. https://www.mdpi.com/2571-8797/6/3/48

Ibarra-Garza, I. P., Ramos-Parra, P. A., Hernández-Brenes, C., & Jacobo-Velázquez, D. A. (2015). Effects of postharvest ripening on the nutraceutical and physicochemical properties of mango (Mangifera indica L. cv Keitt). *Postharvest Biology and Technology, 103*, 45-54. https://doi.org/10.1016/j.postharvio.2015.02.014

Izzo, R., Scartazza, A., Masia, A., Galleschi, L., Quartacci, M. F., & Navari-Izzo, F. (1995). Lipid evolution during development and ripening of peach fruits. *Phytochemistry, 39* (6), 1329-1334. https://doi.org/10.1016/0031-9422(95)00189-E

Jahurul, M. H. A., Zaidul, I. S. M., Ghafoor, K., Al-Juhaimi, F. Y., Nyam, K.-L., Norulaini, N. A. N., & ...Mohd Omar, A. K. (2015). Mango (Mangifera indica L.) by-products and their valuable components: A review. *Food Chemistry, 183*, 173-180. https://doi.org/10.1016/j.foodchem.2015.03.046

Jamsazadeh Kermani, Z., Shpigelman, A., Houben, K., ten Geuzendam, B., Van Loey, A. M., & Hendrickx, M. E. (2015). Study of mango endogenous pectinases as a tool to engineer mango purée consistency. *Food Chemistry, 172*, 272-282. https://doi.org/10.1016/j.foodchem.2014.09.077

Jospeh, K., & Aworh, O. C. (1991). Composition, sensory quality and respiration during ripening and storage of edible wild mango (Irvingia gabonensis). *International*
Journal of Food Science and Technology, 26(3), 337–342. https://doi.org/10.1111/j.1365-2621.1991.tb01170.x

Kalra, S. K., & Tandon, D. K. (1983). Ripening-behaviour of 'Dashehari' mango in relation to harvest period. *Scientia Horticulturae*, 19(3), 263–269. https://doi.org/10.1016/0304-4238(83)90073-0

Karathanos, V. T. (1999). Determination of water content of dried fruits by drying kinetics. *Journal of Food Engineering*, 39(4), 337–344. https://doi.org/10.1016/S0260-8774(98)00132-0

Kaur, B., Panesar, P. S., Anal, A. K., & Chu-Ky, S. (2022). Recent trends in the management of Mango by-products. *Food Reviews International*, 1–21. https://doi.org/10.1080/87559129.2021.2021935

Kaur, B., Panesar, P. S., & Thakur, A. (2025). Extraction and evaluation of structural and physicochemical properties of dietary fiber concentrate from mango peels by using green approach. *Biomass Conversion and Biorefinery*, 15(2), 1815–1824. https://doi.org/10.1007/s13399-021-01740-2

Kim, H., Kim, H., Mosaddik, A., Gyawali, R., Ahn, K. S., & Cho, S. K. (2012). Induction of apoptosis by ethanolic extract of mango peel and comparative analysis of the chemical constitutes of mango peel and flesh. *Food chemistry*, 133(2), 416–422. https://doi.org/10.1016/j.foodchem.2012.01.053

Lanes, É. C. M.d., Lopes, F. C. F., Campos, N. R., Oliveira, J. S.e., Morenz, M. J. F., & Frische-Neto, R. (2016). Comparative efficacy of the conventional and automated methods for determining neutral and acid detergent fiber. *Comunicata Scientiae*, 7(1), 30–37. https://doi.org/10.14295/cs.v7i1.432

Larrauri, J. A., Rupérez, P., Borroto, B., & Saura-Calixto, F. (1996). Mango peels as a new tropical fibre: Preparation and characterization. *LWT - Food Science and Technology*, 29(8), 729–733. https://doi.org/10.1006/fstl.1996.0113

Lewis, C. E. (1978). The maturity of avocados—A general review. *Journal of the Science of Food and Agriculture*, 29(10), 857–866. https://doi.org/10.1002/jsfa.2740291007

MAFF. (2021). *Annual report for agriculture, forestry, and fisheries 2020 and planning for 2021*. Cambodia, Phnom Penh: Ministry of Agriculture, Forestry, and Fisheries. http://www.maff.gov.kh.

Malis-Arad, S., Didi, S., Mizrahi, Y., & Kopeliovitch, E. (1983). Pectic substances: Changes in soft and firm tomato cultivars and in non-ripening mutants. *Journal of Horticultural Science*, 58(1), 111–116. https://doi.org/10.1080/00221589.1983.11515097

Medlicott, A., & Jeger, M. (1987). *The development and application of post-harvest treatments to manipulate ripening in mangoes*. Commonwealth Science Council.

Prasanna, V., Prabha, T. N., & Tharanathan, R. N. (2007). Fruit ripening phenomena-An overview. *Critical Reviews in Food Science and Nutrition*, 47(1), 1–19. https://doi.org/10.1080/10408390600976841

Puupponen-Pimiä, R., Häkkinen, S. T., Aarni, M., Suortti, T., Lampi, A.-M., Eurola, M., & ... Oksman-Caldentey, K.-M. (2003). Blanching and long-term freezing affect various bioactive compounds of vegetables in different ways. *Journal of the Science of Food and Agriculture*, 83(14), 1389–1402. https://doi.org/10.1002/jsfa.1589

Quintana, S. E., Salas, S., & García-Zapateiro, L. A. (2021). Bioactive compounds of mango (Mangifera indica): A review of extraction technologies and chemical constituents. *Journal of the Science of Food and Agriculture*, 101(15), 6186–6192. https://doi.org/10.1002/jsfa.11455

Rivas-Robles, E., Quintana-Obregón, E. A., Marín-Castro, U. R., Ramos-Enríquez, J. R., Vargas-Ortiz, M., & Servent, A. (2024). Postharvest changes of commercial and non-commercial mango (Mangifera indica) germplasm cultivated in Mexico. *Fruits*, 79 (3), 1–16. https://doi.org/10.17660/th2024/011

Roe, B., & Bruemmer, J. H. (1981). Changes in pectic substances and enzymes during ripening and storage of “Keitt” Mangos. *Journal of Food Science*, 46(1), 186–189. https://doi.org/10.1111/j.1365-2621.1981.tb14560.x

Sakamoto, T., Hours, R. A., & Sakai, T. (1995). Enzymic pectin extraction from protoplasts using microbial protoplastinases. *Process Biochemistry*, 30(5), 403–409. https://doi.org/10.1016/0032-9592(94)00027-1

Sharaf, A., Ahmed, F. A., & El-Saadany, S. S. (1989). Biochemical changes in some fruits at different ripening stages. *Food chemistry*, 31(1), 19–28. https://doi.org/10.1016/0308-8146(89)90147-7

Sirisakulwat, S., Nagel, A., Sruamsiri, P., Carle, R., & Neidhart, S. (2008). Yield and quality of pectins extractable from the peels of Thai mango cultivars depending on fruit ripeness. *J Agric Food Chem*, 56(22), 10727–10738. https://doi.org/10.1021/jf802173c

Sudhakar, D. V., & Maini, S. B. (2000). Isolation and characterization of mango peel pectins. *Journal of Food Processing and Preservation*, 24(3), 209–227. https://doi.org/10.1111/j.1745-4549.2000.tb00414.x

Suri, T., & Udry, C. (2022). Agricultural Technology in Africa. *Journal of Economic Perspectives*, 36(1), 33–56. https://doi.org/10.1257/jep.36.1.33

Tandon, D. K., & Kalra, S. K. (1984). Pectin changes during the development of mango fruit cv Dashehari. *Journal of Horticultural Science*, 59(2), 283–286. https://doi.org/10.1080/00221589.1984.11515198

Tesfaye, T. (2017). Valorationisation of mango fruit by-products: Physicochemical characterisation and future prospect. *Chem. Process Eng. Res*, 50, 22–34.

Tharanathan, R. N., Yashoda, H. M., & Prabha, T. N. (2006). Mango (Mangifera indica L.), “the King of fruits”—An overview. *Food Reviews International*, 22(2), 95–123. https://doi.org/10.1080/87559120600574493

Udomkun, P., Romuli, S., Schock, S., Mahayothee, B., Sartas, M., Wossen, T., & ... Müller, J. (2020). Review of solar dryers for agricultural products in Asia and Africa: An innovation landscape approach. *Journal of Environmental Management*, 268, Article 110730. https://doi.org/10.1016/j.jenvman.2020.110730

Van Soest, P. J. (1978). Dietary fibers: Their definition and nutritional properties. *The American Journal of Clinical Nutrition*, 31(10), S12–S20.

Van Soest, P. J., Robertson, J. B., & Lewis, B. A. (1991). Methods for dietary Fiber, neutral detergent Fiber, and nonstarch polysaccharides in relation to animal nutrition. *J Dairy Sci*, 74(10), 3583–3597. https://doi.org/10.3168/jds.S0022-0302 (91)78551-2

Varanyanond, W., Naohara, J., Wongkrajang, K., & Manabe, M. (1999). Changes in pectin content and average molecular weight of pectin during maturation of the mango &ldquo;Kaew&rdquoquo. *Food Science and Technology Research*, 5(4), 362–364. https://doi.org/10.3136/fstr.5.362

Wongkaew, M., Kittiwachana, S., Phuangsaijai, N., Tinpovong, B., Tiyayon, C., Pusadee, T., ... Cheewangkoon, R. (2021). Fruit characteristics, peel nutritional compositions, and their relationships with Mango peel pectin quality. *Plants*, 10(6), 1148. https://www.mdpi.com/2223-7747/10/6/1148.

Yashoda, H. M., Prabha, T. N., & Tharanathan, R. N. (2006). Mango ripening: Changes in cell wall constituents in relation to textural softening. *Journal of the Science of Food and Agriculture*, 86(5), 713–721. https://doi.org/10.1002/jsfa.2404

Zhang, L., Kamitakahara, H., Murayama, H., Ohsako, T., & Itai, A. (2020). Analysis of fruit lignin content, composition, and linkage types in pear cultivars and related species. *Journal of Agricultural and Food Chemistry*, 68(8), 2493–2505. https://doi.org/10.1021/acs.jafc.9b07396