bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of a Floating Photovoltaic System on the Water Evaporation Rate in the Passaúna Reservoir, Brazil
Authors: Santos Fernando Roberto dos , Wiecheteck Giovana Katie , Virgens Filho Jorim Sousa das , Carranza Gabriel Alfredo , Chambers Terrence Lynn , Fekih Afef
Published: August 2022

Freshwater scarcity is a significant concern due to climate change in some regions of Brazil; likewise, evaporation rates have increased over the years. Floating photovoltaic systems can reduce water evaporation from reservoirs by suppressing the evaporating area on the water surface. This work evaluated the effects of floating photovoltaic systems on water evaporation rates in the Passaúna Reservoir, southeastern Brazil. Meteorological data such as temperature, humidity, wind speed, and solar radiation were used to estimate the rate of water evaporation using FAO Penman–Monteith, Linacre, Hargreaves–Samani, Rohwer, and Valiantzas methods. The methods were tested with the Kruskal–Wallis test, including measured evaporation from the nearest meteorological station to determine whether there were significant differences between the medians of the methods considering a 95% confidence level for hypothesis testing. All methods differed from the standard method recommended by the FAO Penman–Monteith. Simulations with more extensive coverage areas of the floating photovoltaic system were carried out to verify the relationship between the surface water coverage area and the evaporation reduction efficiency provided by the system and to obtain the avoided water evaporation volume. For the floating photovoltaic system with a coverage area of 1265.14 m2, an efficiency of 60.20% was obtained in reducing water evaporation; future expansions of the FPS were simulated with coverage areas corresponding to energy production capacities of 1 MWp, 2.5 MWp, and 5 MWp. The results indicated that for a floating photovoltaic system coverage area corresponding to 5 MWp of energy production capacity, the saved water volume would be enough to supply over 196 people for a year. More significant areas, such as covering up the entire available surface area of the Passaúna reservoir with a floating photovoltaic system, could save up to 2.69 hm3 of water volume annually, representing a more significant value for the public management of water resources.
A Literature Review of the Challenges and Opportunities of the Transition from Industry 4.0 to Society 5.0
Authors: Mourtzis Dimitris , Angelopoulos John , Panopoulos Nikos
Published: August 2022

In the era of Industry 4.0, manufacturing and production systems were revolutionized by increasing operational efficiency and developing and implementing new business models, services, and products. Concretely, the milestone set for Industry 4.0 was to improve the sustainability and efficiency of production systems. By extension, the emphasis was focused on both the digitization and the digitalization of systems, providing room for further improvement. However, the current technological evolution is more system/machine-oriented, rather than human-oriented. Thus, several countries have begun orchestrating initiatives towards the design and development of the human-centric aspect of technologies, systems, and services, which has been coined as Industry 5.0. The impact of Industry 5.0 will extend to societal transformation, which eventually leads to the generation of a new society, the Society 5.0. The developments will be focused on the social and human-centric aspect of the tools and technologies introduced under the framework of Industry 4.0. Therefore, sustainability and human well-being will be at the heart of what comes next, the Industry 5.0, as a subset of Society 5.0. Industry 5.0 will build on the foundations laid during Industry 4.0 by emphasizing human-centered, resilient, and sustainable design. Consequently, the authors in this research work, through a critical literature review, aim to provide adequate reasoning for considering Industry 5.0 as a framework for enabling the coexistence of industry and emerging societal trends and needs. The contribution of this research work extends to the provision of a framework to facilitate the transition from Industry 4.0 to Society 5.0.
Pyrolysis Valorization of Vegetable Wastes: Thermal, Kinetic, Thermodynamics, and Pyrogas Analyses
Authors: Elkhalifa Samar , Mariyam Sabah , Mackey Hamish R. , Al-Ansari Tareq , McKay Gordon , Parthasarathy Prakash
Published: August 2022

In comparison to other methods, valorising food waste through pyrolysis appears to be the most promising because it is environmentally friendly, fast, and has a low infrastructure footprint. On the other hand, understanding the pyrolytic kinetic behaviour of feedstocks is critical to the design of pyrolysers. As a result, the pyrolytic degradation of some common kitchen vegetable waste, such as tomato, cucumber, carrot, and their blend, has been investigated in this study using a thermogravimetric analyser. The most prevalent model fitting method, Coats–Redfern, was used for the kinetic analysis, and the various mechanisms have been investigated. Some high-quality fitting mechanisms were identified and used to estimate the thermodynamic properties. As the generation of pyrolysis gases for chemical/energy production is important to the overall process applicability, TGA-coupled mass spectrometry was used to analyse the pyrogas for individual and blend samples. By comparing the devolatilization properties of the blend with single feedstocks, the presence of chemical interactions/synergistic effects between the vegetable samples in the blend was validated. The model, based on a first-order reaction mechanism, was found to be the best-fitting model for predicting the pyrolysis kinetics. The calculated thermodynamic properties (ΔH (enthalpy change ≈ E (activation energy))) demonstrated that pyrolysis of the chosen feedstocks is technically feasible. According to the TGA–MS analysis, blending had a considerable impact on the pyrogas, resulting in CO2 composition reductions of 17.10%, 9.11%, and 16.79%, respectively, in the cases of tomato, cucumber, and carrot. Overall, this study demonstrates the viability of the pyrolysis of kitchen vegetable waste as a waste management alternative, as well as an effective and sustainable source of pyrogas.
Study on the Flow Boiling Heat Transfer Characteristics of the Liquid Film in a Rotating Pipe
Authors: Lian Wenlei , Zhu Yu , Sun Zijian
Published: August 2022

A three-dimensional numerical model is established to study the flow boiling heat transfer characteristics of the liquid film in a rotating pipe, and the effectiveness of the model is verified by a comparison between the numerical results and the experimental results. The effects of rotational speed, heat flux, and Coriolis force on the characteristics of heat transfer of the rotating liquid film are investigated. The conclusions are drawn as follows: (1) The convection of the rotating liquid film is enhanced while the nucleate boiling in the rotating liquid film is inhibited by the increase in the rotational speed; (2) With the influence of these two factors, the heat transfer coefficient increases with centrifugal acceleration increasing from 20 g to 40 g, then decreases with centrifugal acceleration increasing from 40 g to 120 g; (3) The turbulent intensity of the flow with Coriolis force is obviously increased compared to that without Coriolis force when the centrifugal acceleration ranges from 20 g to 80 g, which shows no increase at higher centrifugal accelerations when the turbulence is sufficiently strong. The Coriolis force also has an impact on the heat transfer coefficient of the liquid film, which should not be ignored when studying the boiling heat transfer of a rotating liquid film.
Second Harmonic Current Reduction Control for Two-Stage Inverter with a New Inductor Current Feedback Path
Authors: Dong Hao , Xu Jiaqun
Published: August 2022

The instantaneous output power of the two-stage inverter pulsates at twice the output frequency, resulting in the second harmonic current (SHC) in the front-end dc-dc converter. To reduce the SHC in the inductance branch while maintaining good dynamic performance, this paper proposes a control scheme based on a new inductor current feedback path in the front-end buck converter. In the scheme, through the equivalent gain, the virtual resistor, and the bandpass filter, the inductor current is fed to the front of the voltage regulator. The feedback function simplification is studied and the implementation of the proposed scheme is illustrated. With considerations of both reducing the SHC and improving the dynamic performance, the parameter design approach for the feedback function is also presented for the proposed SHC reduction control scheme, and the performance analysis and comparison from the viewpoint of output impedance are provided. The simulation model and the prototype of a 10 kW two-stage inverter are constructed. The simulation and experimental results about the low SHC in the front-end buck converter and the fast dynamic response during the load transient verify the effectiveness of the proposed scheme.
Sector Coupling Potential of a District Heating Network by Consideration of Residual Load and CO2 Emissions
Authors: Werner Melanie , Muschik Sebastian , Ehrenwirth Mathias , Trinkl Christoph , Schrag Tobias
Published: August 2022

The growing share of fluctuating renewable electricity production within the German energy system causes the increasing necessity for flexible consumers, producers, and storage technologies to balance supply and demand. District heating networks with combined heat and power units, Power-to-Heat applications, and thermal energy storage capacities can serve as one of these flexible options. In this context, a simulation model of the district heating network of the rural community Dollnstein, Germany, was built. With the residual load of different regional areas (Germany, Bavaria, Eichstätt, Dollnstein) it is investigated, how the heat generators can operate in an electricity market beneficial way. Two different control algorithms were evaluated: Due to a correlation between the residual loads and the CO2 emissions of the electricity mix, the CO2 savings achieved by this control algorithm are determined. Another way to operate electricity market beneficial is to consider the current CO2 emissions of each region. The main outcomes of this paper are, that there is a high potential for sector coupling by shifting the operation times of a CHP and a heat pump according to the residual load. The electricity demand of the heat pump can be met in terms of low CO2 emissions of the electricity mix, while the CHP can replace electricity with high CO2 emissions. These results can be improved, by considering not the residual load but the current CO2 emissions in the control algorithm.
Theoretical and Experimental Analysis of Engine Performance and Emissions Fuelled with Jojoba Biodiesel
Authors: Mustayen A. G. M. B. , Rasul M. G. , Wang Xiaolin , Bhuiya M. M. K. , Negnevitsky Michael , Hamilton James
Published: August 2022

Over many decades, isolated regions (e.g., islands, rural and remote areas) have heavily relied on diesel engine for producing power and energy. However, due to depleting fossil fuels and concerning emissions, biodiesels could be the substitute for diesel in power generation sectors. This study developed a single-zone thermodynamic model to predict the engine performances such as brake power (BP), torque, brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC) and ignition delay (ID) times for diesel and jojoba biodiesel. The experiments were conducted on a fully automated, 4-cylinder, 4-stroke, liquid-cooled direct injection 3.7-L diesel engine fueled with diesel (D100) and three jojoba blends (JB5, JB10, and JB20) to validate the model. The performance simulation results agreed with experimental data for all tested fuels at 1200 to 2400 rpm speed and 25%, 50%, 75%, and 100% loading operation. The minimum error (3.7%) was observed for BP for D100 at 2000 rpm and 100% load, and the maximum error (19.2%) was found for JB10 at 1200 rpm and 25% loading operation. As load increases from 25 to 100%, the BSFC and torque difference between diesel and JB20 decreases from 10 to 6.5 and 9 to 6%, respectively. A shorter ID time was observed in JB5 compared to JB10 and JB20. Furthermore, a significant reduction was observed in CO (7.55%) and HC (6.65%) emission for JB20 at 25% and 1200 rpm compared to diesel fuel; however, NOx emission was increased up to 10.25% under any given conditions.
Distributed Generation Power Systems in Wastewater Management
Authors: Vrzala Matouš , Goňo Miroslava , Goňo Radomír , Kotulla Michal , Wzorek Małgorzata , Leonowicz Zbigniew
Published: August 2022

The article concerns the energy security of a wastewater treatment process caused by unforeseen situations related to the risk of electrical power outages. In this case, renewable energy sources based on distributed generation power systems can solve this problem in each wastewater treatment plant. The article highlights e related challenges and proposes the direction of solutions in this regard based on Czech conditions. The first part of the paper deals with the consequences of long-term outage of wastewater treatment plants on the population and the environment. There are several solutions presented for blackout conditions, and model calculations are made based on data from a Czech wastewater treatment plant. Diesel engine-generators, biogas as a cogeneration source of heat and electricity, solar panels with storage systems and combined biogas and solar systems were considered as approaches to provide energy autonomy during a blackout in a wastewater treatment plant. Special attention was paid to a combination of CHP units with solar panels and batteries. The results were evaluated for three different locations for this combination. It was concluded that biogas combustion in the CHP unit was the most profitable option, allowing the production of electricity independently of the grid for its own consumption and possibly for other operations. The last part of the paper deals with the transition to island operation, which must occur during a blackout. This transition is more difficult for both solar panels and cogeneration units if they were to supply electricity to the grid before a blackout. The transition to energy island operation could be ensured by frequency relay and processor devices to control the circuit breaker. Then, to maintain island operation, it would be necessary to have an automatic load shedding/application system.
Embedded FPGA Controllers for Current Compensation Based on Modern Power Theories
Authors: de Andrade Nicholas D. , Godoy Ruben B. , Batista Edson A. , de Brito Moacyr A. G. , Soares Rafael L. R.
Published: August 2022

This work compares the performance of two embedded FPGA controllers that can be used in Active Parallel Power Filters (APPF). Both controllers are validated through the FPGA-in-the-loop (FIL) technique, the algorithm’s synthesis is accomplished using the Quartus II® platform, and the board used is from Altera®—Cyclone IV DE2-115. The main difference between the controllers resides in the power theories used to obtain the currents for compensation. The results confirm that the FPGA is a suitable digital device for the parallel operation of multiple compensators and calculation stages, being a viable solution for the requirements imposed in the control of APPF. Furthermore, the effectiveness of the FIL technique for validating the operation of digital circuits and control systems is also confirmed. Finally, a comparison between the processing costs of each of the implemented power theories is presented to guide novel proposals.
Net Primary Productivity of Forest Ecosystems in the Southwest Karst Region from the Perspective of Carbon Neutralization
Authors: Zhou Binghuang , Liao Zhangze , Chen Sirui , Jia Hongyu , Zhu Jingyu , Fei Xuehai
Published: August 2022

The net primary productivity (NPP) of forest ecosystems is an important factor for understanding the carbon budget of forest ecosystems. There have been many studies on the spatialtemporal characteristics and change trends of the NPP in southwest areas based on observation and remote sensing models. A comprehensive view of the overall state of the research on the carbon budget and a deeper exploration of its laws and effects are needed to reach a clear conclusion and accurately assess the NPP of forests in southwest China. Therefore, in this paper, we aim to highlight the relevant achievements in the study of the NPP of forest ecosystems, to summarize the research progress and spatial–temporal distribution law of the estimation of the NPPs of forest ecosystems, to analyse the relationship between the NPP and climate factors (such as temperature, precipitation and VPD), and to identify the main unsolved issues and suggest directions for future research. Our summary is expected to serve as a reference for forest ecosystem carbon budget management in the southwest and as a starting place for further research, and to promote the realization of the “double carbon” goal.
Isolated Trees in Two Tibetan Plateau Treelines Reveal Growth Plasticity to Harsh Conditions of the Little Ice Age
Authors: Zheng Jiacheng , Lyu Lixin , Zhang Qibin
Published: August 2022

Trees greater than 150 years old growing in the current treelines were most likely isolated tree outposts above previous treelines of the Little Ice Age (LIA). An intuitive question is, how did these isolated trees grow at such a high elevation in the cold environment? Here, we tackle this question using tree-ring width data of the Northern Hemisphere’s highest treelines at 4900 m a.s.l. (Basu) and 4680 m a.s.l. (Langkazi) on the Tibetan Plateau. The results showed that an age-related exponential growth trend did not exist in most of the ring-width sequences of the sampled trees. The values of ring widths in the isolated trees had a similar pattern of probability distribution during and after the LIA. The coefficients of variation in ring widths of the isolated trees were significantly greater than those of the non-isolated trees in their common growth period. Synchronicity of annual change in radial growth among trees varied in time. These results indicated that the isolated trees in the LIA developed an adaptive ability to slow down radial growth rate and modulate growth synchronicity among individuals in cold stressful environments. Our study highlights growth plasticity in isolated trees above treelines for coping with harsh conditions in the LIA.
Prediction of Wildfire Fuel Load for Pinus densiflora Stands in South Korea Based on the Forest-Growth Model
Authors: Lee Sun-Joo , Lee Young-Jin , Ryu Ju-Yeol , Kwon Chun-Geun , Seo Kyung-Won , Kim Sung-Yong
Published: August 2022

A prediction model was developed for the wildfire fuel load of Korean red pine (Pinus densiflora) stands with susceptibility to forest fire based on the forest-growth model. Furthermore, a time-series analysis was performed on the variation in forest-fire fuel load according to forest management. National Forest Inventory stand data of 1434 plots for P. densiflora stands were used, and the final forest-fire fuel load prediction model was developed using the Weibull function and mortality model. The fit index of the diameter distribution model ranged from 0.58 (0th percentile) to 0.96 (50th percentile), and that of the mortality model was 0.68. The prediction of the stand growth variation after 20 years based on the growth data of managed and unmanaged stands indicated a mean stand density of 1518 trees per ha for unmanaged stands, and 885 trees per ha for managed stands. Regarding the variation in the available canopy fuel load distribution, the predicted annual increase was approximately 0.7 ton/ha for unmanaged stands and approximately 0.5 ton/ha for managed stands. These findings will contribute to setting fuel management criteria to prevent forest fire spread while providing the quantitative data of the characteristics of stand growth variation and the predicted wildfire fuel load.
Temperature Sensitivity of Soil Respiration in Two Temperate Forest Ecosystems: The Synthesis of a 24-Year Continuous Observation
Authors: Kurganova Irina , Lopes de Gerenyu Valentin , Khoroshaev Dmitry , Myakshina Tatiana , Sapronov Dmitry , Zhmurin Vasily
Published: August 2022

Soil respiration (SR) is one of the largest fluxes in the global carbon cycle. The temperature sensitivity of SR (often termed as Q10) is a principal parameter for evaluating the feedback intensity between soil carbon efflux and global warming. The present study aimed to estimate the seasonal and interannual dynamics of the temperature sensitivity of SR based on a long-term 24-year series of measurements in two temperate forest ecosystems in European Russia. The study was conducted in a mature mixed forest with sandy Entic Podzol and in a secondary deciduous forest with loamy Haplic Luvisol. The SR rate was measured continuously from December 1997 to November 2021 at 7–10-day intervals using the closed chamber method. Sandy Entic Podzol demonstrated a higher temperature sensitivity of SR in comparison with loamy Entic Luvisol. The Q10 values for both soils in dry years were 1.3–1.4 times lower than they were in the years with normal levels of humidity. For both types of soil, we observed a significant positive correlation between the Q10 values and wetness indexes. The interannual variability of Q10 values for SR in forest soils was 18%–40% depending on the calculation approach and levels of aridity/humidity over the growing season. The heterogeneous Q10 values should be integrated into SR and C balance models for better predictions.
Spatial Distribution Pattern and Genetic Diversity of Quercus wutaishanica Mayr Population in Loess Plateau of China
Authors: Hu Dong , Xu Yao , Chai Yongfu , Tian Tingting , Wang Kefeng , Liu Peiliang , Wang Mingjie , Zhu Jiangang , Hou Dafu , Yue Ming
Published: August 2022

The Quercus wutaishanica forest influences the ecological environment and climate characteristics and plays an important ecological role in the Loess Plateau region. However, we still know relatively little about the genetic diversity and spatial distribution of Q. wutaishanica. Here, we assessed the genetic diversity of Q. wutaishanica using simple sequence repeats and used the point pattern method to analyze the spatial distribution patterns as well as intraspecific relationships. Our results indicate that the diameter structure of the Q. wutaishanica population was inverted J-type, showing a growing population. In addition, the population maintained high genetic diversity on a small scale. Due to dispersal constraints, the spatial distribution pattern of Q. wutaishanica seedlings (DBH < 1 cm) tended to aggregate at small scales and the degree of aggregation decreased with increasing spatial scale. However, trees (DBH > 5 cm) and saplings (1 cm ≤ DBH < 5 cm) showed more random distribution at the scale, indicating that Q. wutaishanica individuals shift from aggregation to random distribution at the spatial scale. In addition, although individuals of different diameter classes showed facilitative (trees vs. saplings, 5–6.5 m) and competitive effects (trees vs. seedlings, 13.5–16 m) on some scales, they showed no correlation on other scales, especially for saplings and seedlings, where they were not correlated on any scale. The results contribute to revealing the status and dynamics of Q. wutaishanica in the Loess Plateau, thereby providing a theoretical basis for further study on the maintenance mechanism of the population.
Smart Classroom Teaching Strategy to Enhance Higher Order Thinking Skills (HOTS)—An Agile Approach for Education 4.0
Authors: Venkatraman Sitalakshmi , Benli Fahri , Wei Ye , Wahr Fiona
Published: August 2022

The development of Industry 4.0 revolutionising the concept of automation and digitisation in an organisation poses a huge challenge in employee knowledge and skills to cope with the huge leap from Industry 3.0. The high-level digitisation of an organisation requires the workforce to possess higher order thinking skills (HOTS) for the changing job roles matching the rapid technological advancements. The Education 4.0 framework is aimed at supporting the Industry 4.0 skills requirement not only in digital technologies but more towards soft skill development such as collaboration and lifelong learning. However, the education sector is also facing challenges in its transition from Education 3.0 to Education 4.0. The main purpose of the paper is to propose an Agile approach for developing smart classroom teaching strategies that foster employee adaptability with the new learning paradigm of upskilling in line with Industry 4.0. By adopting an exploratory research methodology, the pilot study investigates the implementation of the proposed Agile approach in a higher education setting for graduates to achieve HOTS using smart classroom teaching strategies. This study uses learning theories such as experiential learning in smart classroom environments to enhance students’ HOTS individually as well as collaboratively in an Agile iterative manner. This is the first empirical study carried out for graduates specialising in the Business Analytics skillset required for Industry 4.0. The findings of the pilot study show promising results that pave the way for further exploration and pedagogical insights in this research direction.
Experimental Investigation of the Axial Crushing Response of Flax/Glass Eco-Hybrid Self-Supporting Web Composites
Authors: Israr Haris Ahmad , Wong King Jye , Koloor Seyed Saeid Rahimian
Published: August 2022

This study investigates the quasi-static axial crushing tests of eco-hybrid composites based on flax and E-glass fibres strengthened with polyester resin. Five different configurations of self-supporting webs were fabricated to investigate the crushing behaviours of this eco-hybrid composite with different stacking sequences based on intercalation and sandwich-like sequences. The effect of different open-section web profiles was also investigated. The results were plotted in load-displacement curves and the specific energy absorption (SEA), as well as the crushing force efficiency (CFE), were calculated to evaluate the crushing response of each configuration. The test results verified the crushing mechanisms related to the energy absorption depending on the stacking sequence as well as the frontal profile. In this study, all specimens with the intercalation stacking sequence have achieved higher SEA and CFE than specimens with a sandwich-like stacking sequence. In terms of the frontal profile, the sine wave hat shape had the highest CFE, up to 80% compared to other web profiles. Thus, it demonstrated the capability of a sine wave hat-shape eco-composite based on flax fibre to be applied as a crashworthy material.
Feeding Selectivity of Ruditapes philippinarum on Phytoplankton
Authors: Liu Yin , Song Lun , Song Guangjun , Wu Jinhao , Wang Kun , Wang Zhaohui , Liu Suxuan
Published: August 2022

A monthly survey of the feeding selectivity of Ruditapes philippinarum in the Yalu River Estuary in 2020–2021 was conducted using high-throughput sequencing identification and visual grading technology. The results showed that the most-dominant species in the water of the shellfish culture area and in the stomachs of R. philippinarum was Karlodinium veneficum in those years. The selectivity index (E) indicated that R. philippinarum avoided consuming Bacillariophyta, Chrysophyta and Cryptophyta throughout the year and preferentially consumed Dinophyta and Chlorophyta. In 2020, the annual average biomass of Dinophyta, Bacillariophyta, Chlorophyta, Dictyochophyta, Cryptophyta and Chrysophyta in the stomach contents of R. philippinarum was 54:14:16:1:10:4; it was 41:12:28:0:1:17 in 2021. The annual average biomass ratio of picophytoplankton, nanophytoplankton and microphytoplankton in the stomachs of R. philippinarum was 13:48:39 in 2020; it was 14:66:20 in 2021. R. philippinarum actively fed on nanophytoplankton and avoided picophytoplankton. Among the phytoplankton of different sizes and groups that R. philippinarum prefer to feed, chemical oxygen demand (COD) and organic phosphorus (DOP) have a significant negative effect on the nanophytoplankton community, pH has a positive effect on the Dictyochophyta community and COD and the inorganic nitrogen to phosphorus ratio (DI-N/P) have a significant positive effect on the Chlorophyta community.
Evaluation of Biochemical Properties, Antioxidant Activities and Phenolic Content of Two Wild-Grown Berberis Fruits: Berberis nummularia and Berberis atrocarpa
Authors: Abudureheman Buhailiqiemu , Zhou Xinyue , Shu Xipan , Chai Ziqi , Xu Yongping , Li Shuying , Tian Jinhu , Pan Haibo , Ye Xingqian
Published: August 2022

To evaluate the potential health-promoting benefits of Berberis nummularia and B. atrocarpa fruits, the biochemical properties (nutrition component, mineral substance, organic acids), total phenolic and flavonoid content and antioxidant (DPPH, FRAP, ABTS and ORAC) capacity of ethanol extracts of B. nummularia and B. atrocarpa fruits wild-grown in Xinjiang were analyzed. The results indicated that there were no meaningful differences (p > 0.05) between the ash (1 ± 0.1 and 1 ± 0.0 g/100 g), fiber (16 ± 1.0 and 18 ± 1.4) and carbohydrate (57 ± 1.8 and 56 ± 1.8 g/100 g) content, respectively, in the dry fruits of B. nummularia and B. atrocarpa. The total fat (7 ± 0.4 and 5 ± 0.1 mg/100 g), soluble sugar (23 ± 0.6 and 12 ± 1.4 g/100 g), titratable acidity (18 ± 2.5% and 14 ± 1.3%) content, and energy value (330.86 and 314.41 kcal/100 g) of B. nummularia was significantly higher than that of B. atrocarpa fruits. Both species contain malic acid, acetic acid, tartaric acid, citric acid and fumaric acid, in which, malic acid is the dominant organic acid. The organic acid and mineral components of B. nummularia fruits were significantly higher than that of B. atrocarpa (p < 0.05). The total phenolic and flavonoid content of B. nummularia were 2 ± 0.0 mg GA/g DW and 2 ± 0.0 mg RE/g DW, respectively, which were significantly lower than the total phenolic and flavonoid content of B. atrocarpa (12 ± 0.1 mg GA/g DW and 9 ± 0.0 mg RE/g DW). The antioxidant capacity of B. nummularia (4 ± 0.1 mg Ascorbic acid/g DW for DPPH, 32 ± 0.1 mg Trolox/g DW for FRAP, 80 ± 3.0 mg Trolox/g DW for ABTS and 60 ± 3.6 mg Trolox/g for ORAC was significantly lower than that of B. atrocarpa (12 ± 0.0 mg Ascorbic acid/g DW for DPPH, 645 ± 1.1 mg Trolox/g DW for FRAP, 304 ± 3.0 mg Trolox/g DW for ABTS and 155 ± 2.8 mg Trolox/g for ORAC). B. atrocarpa fruits showed significantly higher antioxidant capacity than that of B. nummularia. The fruits of the two species can be used in food coloring and nutritional supplements, and consumption of the fruits can aid in weight control and reduce blood glucose or cholesterol.
Determination of Nitrate and Nitrite in Swiss Chard (Beta vulgaris L. subsp. vulgaris) and Wild Rocket (Diplotaxis tenuifolia (L.) DC.) and Food Safety Evaluations
Authors: Iammarino Marco , Berardi Giovanna , Vita Valeria , Elia Antonio , Conversa Giulia , Di Taranto Aurelia
Published: August 2022

Nitrite and nitrate levels in vegetables are a matter of concern due to their toxicity at high levels and nitrate high accumulation. Moreover, there is a lack of knowledge about their levels in some types of widely consumed vegetables such as chard and rocket. In this study, 124 Swiss chard and wild rocket samples were analyzed for determining nitrite and nitrate using validated and accredited analytical methods by ion chromatography with conductivity detection. High nitrite concentrations, up to 219.5 mg kg−1 f.w., were detected in one Swiss chard and three wild rocket samples. One Margin of Safety (MoS) value was <1. Regarding nitrate, in Swiss chard samples the mean concentration (2522.6 mg kg−1) was slightly higher than those reported in the literature for spinach and lettuce. No MoS was <1, but 83% of values were <100. Nitrate concentrations higher than the legal limit were quantified in 11 rucola samples. The verification of 25% of wild rocket samples with nitrate concentration higher than the legal limit confirmed the need for official control. This study also suggests the introduction of legal limits for nitrite/nitrate in Swiss chard and nitrite in wild rocket.
Development of High-Fibre and Low-FODMAP Crackers
Authors: Radoš Kristina , Čukelj Mustač Nikolina , Varga Katarina , Drakula Saša , Voučko Bojana , Ćurić Duška , Novotni Dubravka
Published: August 2022

Since there are no products in the European market labelled as low-FODMAP (low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols), patients with irritable bowel syndrome and non-celiac wheat sensitivity often consume gluten-free products. These naturally contain little FODMAP, but have poorer sensory properties and lower nutritional value. This study aimed to develop sensory attractive crackers with high-fibre and low-FODMAP content. Various gluten-free flours (wholemeal buckwheat and millet, white maize), pumpkin seed meal, chia seeds, flax seeds, rice protein, sweet potato, sourdough, and spices were used to develop nine formulations. Using a nine-point hedonic scale and ranking test, four best-scored products were selected for which descriptive sensory analysis was performed and nutritional value and fructan content were determined. Crackers made from maize and millet flour mixtures (ratio 1:2.5) with sourdough and with chia or flax seed addition were rated highest for overall impression (8.2 and 7.0, respectively). Generally, high-fibre content, hardness, chewiness, dark colour, and bitterness lower the acceptability of crackers, but the addition of spices and sourdough can improve their acceptability and marketability. The crackers could be labelled as “gluten-free”, “low-FODMAP” (<0.12 g/100 g), “naturally high-fibre” (7–10 g/100 g of which 17–23% are soluble), and “high in protein” (24–26 g/100 g).
Determination of 2-Pentanol Enantiomers via Chiral GC-MS and Its Sensory Evaluation in Baijiu
Authors: Hu Lisha , Qiu Shuyi , Dai Yifeng , Tian Luqin , Wei Chaoyang
Published: August 2022

The enantiomeric contents of 2-pentanol of Baijiu were analyzed by liquid-liquid extraction (LLE) coupled with gas chromatography-mass spectrometry (GC-MS) using β-cyclodextrin as a chiral stationary phase. In this study, the average enantiomeric ratios R:S were 72:28, 64:36, and 94:6 in soy sauce aroma-type Baijiu (SSB), strong aroma-type Baijiu (STB), and light aroma-type Baijiu (LTB), respectively, and only (R)- configuration was found in rice aroma-type Baijiu (RTB). The highest enantiomeric concentration of 2-pentanol was found in STB. (R)-2-pentanol dominated in 48 Baijiu studied, and the concentration of (R)-2-pentanol was higher than that of the (S)-configuration. The results showed that the enantiomers of 2-pentanol were discrepant in different aroma types of Baijiu, and it may be the result of differences in raw materials, environment, and production processes. The 2-pentanol enantiomers had different odor characteristics, with different olfactory thresholds in pure water and 46% ethanol solutions by sensory analysis. (R)-2-pentanol was described as paint, rubber, grease, while the (S)-form had mint, plastic, and pungent notes. The olfactory thresholds of (R)- and (S)-form were 163.30 mg/L and 78.58 mg/L in 46% ethanol and 12.62 mg/L and 3.03 mg/L in pure water, respectively. The different enantiomeric distribution and aroma characteristics of the 2-pentanol enantiomers in Baijiu could be a potential marker for determining adulteration.
A Novel Ethanolic Two-Phase System Based on Deep Eutectic Solvents and Amphiphilic Copolymer for the Extraction of Neohesperidin and Naringin from the Pomelo Peel
Authors: Wang Shanshan , Qin Zongkui , Wang Yicong , Liu Leilei , Tan Zhijian
Published: August 2022

A novel ethanolic two-phase system (ETPS) composed of Pluronic®L-64 (PL 64) and deep eutectic solvents (DESs) was constructed for the separation of two similar flavonoids of naringin (Nar) and neohesperidin (Neo) from the pomelo peel. The selectivity (S) data showed that DES prepared from tetrabutylammonium bromide (N4444Br) and glycerol (Gly) had the optimal distribution efficiency for Nar and Neo standards. A binodal curve of N4444Br-Gly/PL 64/ethanol system fitted to the nonlinear Merchuk relationship showed that the biphasic region was narrow for ETPS. The influences of the mass ratio of DESs and PL 64, DES concentration, PL 64 concentration, molar ratio of DESs, temperature, phosphate buffer solution, and ethanolic pH were studied in single-factor experiments. Under the optimal conditions, the maximum extraction efficiency (ENar = 68.32%, ENeo = 86.09%), partition coefficient (KNar = 6.66, KNeo = 19.13), and S (2.88) were obtained in the DESs-rich (bottom) phase. N4444Br-Gly, Nar, and Neo with recovery yields of 78.12%, 66.61%, and 68.03%, respectively, had been recovered using D101 macroporous resin. This proposed ETPS is efficient and environmentally friendly and is expected to avail meaningful references for the separation of natural products with similar structures.
Effect of Multi-Mode Thermosonication on the Microbial Inhibition and Quality Retention of Strawberry Clear Juice during Storage at Varied Temperatures
Authors: Feng Min , Chitrakar Bimal , Chen Jianan , Islam Md. Nahidul , Wei Benxi , Wang Bo , Zhou Cunshan , Ma Haile , Xu Baoguo
Published: August 2022

Strawberry juice, which is rich in nutrients and charming flavor, is favored by consumers. To explore whether multi-mode thermosonication (MTS) can ensure the quality stability of strawberry clear juice (SCJ) during storage, the effects of microbial inhibition, enzyme activity, and physicochemical properties of SCJ pretreated by MTS were evaluated during storage at 4, 25, and 37 °C in comparison with thermal pretreatment (TP) at 90 °C for 1 min. The MTS, including dual-frequency energy-gathered ultrasound pretreatment (DEUP) and flat sweep-frequency dispersive ultrasound pretreatment (FSDUP), were conducted at 60 °C for 5 and 15 min, respectively. Results showed that the total phenols, flavonoids, anthocyanins, ascorbic acid, and DPPH free radical scavenging ability of SCJ decreased during the storage period. The control sample of SCJ was able to sage for only 7 days at 4 °C based on the microbiological quality, while the FSDUP and DEUP group extended the storage period up to 21 and 14 days, respectively. The polyphenol oxidase in SCJ pretreated by MTS did not reactivate during the storage period. The MTS remarkably (p < 0.05) reduced the color deterioration, browning degree, and nutrient degradation during the storage period. Moreover, the FSDUP group exhibited the maximum shelf life with a minimum loss of quality, demonstrating that it was the most suitable processing method for obtaining high-quality SCJ. It can be concluded that the MTS has the potential to inhibit enzymatic browning, inactivating microorganisms, preserve original quality attributes, and prolong the shelf life of SCJ.
Effectiveness of Fish Oil-DHA Supplementation for Cognitive Function in Thai Children: A Randomized, Doubled-Blind, Two-Dose, Placebo-Controlled Clinical Trial
Authors: Sittiprapaporn Phakkharawat , Bumrungpert Akkarach , Suyajai Prayoon , Stough Con
Published: August 2022

The effects of fish oil (FO) or omega-3 supplementation on cognition has been the subject of several previous clinical trials. However, the effect of different doses taken chronically on cognition in children has not been well studied. In order to address this gap in our knowledge, we conducted a randomized, double-blind, placebo-controlled clinical trial. A total of one hundred and twenty healthy, cognitively normal Thai children aged 6–12 years old consumed daily low dose FO (260 mg Docosahexaenoic acid (DHA)), high dose FO (520 mg DHA), or placebo (Soybean oil) for 12 weeks. Cognitive function was assessed using a computerized cognitive battery, including the Go/NoGo, N-Back, and Digit Span tests as well as concurrent event-related potentials (ERPs), which together measured attention, processing speed, inhibition, and memory at baseline and 12 weeks. We hypothesized that compared to placebo, the two FO groups would show improved cognitive performance and shorter ERP latencies. In total, 42, 39, and 39 participants completed each of the test (FO-A, FO-B) and placebo groups (P) allocations, respectively, and were analyzed (120 in total across the three groups). No significant differences were observed between reaction times (RTs), accuracy, or error rates for all three of the cognitive tests. The ERP measurement and analysis of brain activity during the cognitive tests showed an increase in ERP amplitude. For all cognitive tests, there was a dose-response effect of FO on ERP amplitudes. These findings indicate that fish oil intake leads to a consistent improvement in attention and cognitive processing ability measured by changes in brain activity during working and long-term memory processes. This is the first study to directly quantify such an effect through simultaneous measurement of manual and mental activity during cognitive tasks following chronic FO use in children.
Phytochemical Profile and Antioxidant, Antiproliferative, and Antimicrobial Properties of Rubus idaeus Seed Powder
Authors: Mannino Giuseppe , Serio Graziella , Gaglio Raimondo , Busetta Gabriele , La Rosa Lorenza , Lauria Antonino , Settanni Luca , Gentile Carla
Published: August 2022

In the context of the contemporary research on sustainable development and circular economy, the quest for effective strategies aimed at revaluation of waste and by-products generated in industrial and agricultural production becomes important. In this work, an ethanolic extract from red raspberry (Rubus idaeus) seed waste (WRSP) was evaluated for its phytochemical composition and functional properties in term of antioxidative, antiproliferative, and antimicrobial activities. Chemical composition of the extract was determined by both HPLC-ESI-MS/MS and spectrophotometric methods. Phytochemical analysis revealed that flavan-3-ols and flavonols were the major phenolic compounds contained in WRSP. The extract demonstrated very high radical-scavenging (4.86 ± 0.06 µmol TE/DW) and antioxidant activity in a cell-based model (0.178 ± 0.03 mg DW/mL cell medium). The WRSP extract also exhibited antiproliferative activity against three different epithelial cancer cell lines (MCF-7, HepG2, and HeLa cells) in a dose-dependent manner. Finally, microbiological assays showed the absence of colonies of bacteria and microscopic fungi (yeasts and molds) and revealed that the WRSP extract has a large inhibition spectrum against spoilage and pathogenic bacteria, without inhibitory activity against pro-technological bacteria. In conclusion, the obtained results show that WRSP is a rich source of phytochemical compounds exerting interesting biological activities. For these reasons WRSP could find applications in the nutritional, nutraceutical, and pharmacological fields.
Influence of Common Reducing Agents on Technological Parameters of Dry-Fermented Sausages with Low Fat Content
Authors: Vioque-Amor Montserrat , Gómez-Díaz Rafael , Clemente-López Ignacio , Sánchez-Giraldo Maite , Avilés-Ramírez Carmen
Published: August 2022

The production of dry-fermented sausages currently presents several challenges to be addressed: nutrition, health, sensory traits and technology are among the main issues that concern consumers and the meat industry. The objective of this study was to evaluate the effect of different reducing agents commonly used in the manufacture of dry-fermented sausages (salchichon type) with low fat content on the technological characteristics of the product. Four different reducing agents (ascorbic acid, a starter culture, sodium ascorbate and glucono-delta-lactone) were added to the meat batter to assess their impact on the physico-chemical traits, instrumental color, residual nitrates and nitrites and lipid oxidation of this meat product. High nitrate values were observed during both ripening and storage periods. All batches presented lipid oxidation values below the threshold that indicates meat rancidity. Adjustments of the original lean:fat proportion must be carried out on this low fat content sausage to obtain profitable results. Starter culture and sodium ascorbate have shown the best reducing and antioxidant activities among the additives studied. Once we have the technical design of the product, the next step will be oriented to identify the sensory characteristics in order to find a gap in the market.
Altering the Chain Length Specificity of a Lipase from Pleurotus citrinopileatus for the Application in Cheese Making
Authors: Broel Niklas , Sowa Miriam A. , Manhard Julia , Siegl Alexander , Weichhard Edgar , Zorn Holger , Li Binglin , Gand Martin
Published: August 2022

In traditional cheese making, pregastric lipolytic enzymes of animal origin are used for the acceleration of ripening and the formation of spicy flavor compounds. Especially for cheese specialities, such as Pecorino, Provolone, or Feta, pregastric esterases (PGE) play an important role. A lipase from Pleurotus citrinopileatus could serve as a substitute for these animal-derived enzymes, thus offering vegetarian, kosher, and halal alternatives. However, the hydrolytic activity of this enzyme towards long-chain fatty acids is slightly too high, which may lead to off-flavors during long-term ripening. Therefore, an optimization via protein engineering (PE) was performed by changing the specificity towards medium-chain fatty acids. With a semi-rational design, possible mutants at eight different positions were created and analyzed in silico. Heterologous expression was performed for 24 predicted mutants, of which 18 caused a change in the hydrolysis profile. Three mutants (F91L, L302G, and L305A) were used in application tests to produce Feta-type brine cheese. The sensory analyses showed promising results for cheeses prepared with the L305A mutant, and SPME-GC-MS analysis of volatile free fatty acids supported these findings. Therefore, altering the chain length specificity via PE becomes a powerful tool for the replacement of PGEs in cheese making.
Study on Infinitely Many Solutions for a Class of Fredholm Fractional Integro-Differential System
Authors: Li Dongping , Li Yankai , Chen Fangqi
Published: August 2022

This paper deals with a class of nonlinear fractional Sturm–Liouville boundary value problems. Each sub equation in the system is a fractional partial equation including the second kinds of Fredholm integral equation and the p-Laplacian operator, simultaneously. Infinitely many solutions are derived due to perfect involvements of fractional calculus theory and variational methods with some simpler and more easily verified assumptions.