Soybean Residue Research Articles

Enhancing Gluten-Free Crispy Waffles with Soybean Residue (Okara) Flour: Rheological, Nutritional, and Sensory Impacts.

The incorporation of okara, a by-product of soybean milk production, into gluten-free products such as crispy waffles poses challenges due to the absence of gluten's viscoelastic properties and the high fiber content of okara. This study aimed to evaluate the effects of okara flour on the rheological properties, physical attributes, and sensory qualities of gluten-free waffles. Waffle batters with varying levels of okara flour (10%, 20%, 30%, and 40%) were prepared, and their rheological properties were analyzed using oscillatory shear and creep-recovery tests. Physical properties, proximate composition, cholesterol and glucose adsorption capacities, storage stability, and sensory attributes were also assessed. The results demonstrated that increasing okara flour content improved batter elasticity and viscosity (with complex viscosity reaching up to 10,923 Pa·s for 40% okara flour) but decreased spread ratio by up to 45% and increased moisture content by approximately 2.7%. Higher okara content also led to a 16% decrease in brightness (L*) and increased hardness, reaching 325.26 g/s at 40% substitution. Sensory evaluation revealed that waffles with 30% okara flour were preferred for their texture and overall liking, with a score of 7.43 compared to higher substitution levels. Cholesterol and glucose adsorption capacities were high in okara flour, contributing to potential health benefits. Storage stability tests showed acceptable moisture content, water activity, and microbiological safety over 60 days, though hardness decreased by about 42%. In conclusion, okara flour enhances the nutritional profile of gluten-free waffles, but its impact on texture and flavor requires careful formulation adjustments to optimize consumer acceptance.

Impact of Crop Residue, Nutrients, and Soil Moisture on Methane Emissions from Soil under Long-Term Conservation Tillage

Greenhouse gas emissions from agricultural production systems are a major area of concern in mitigating climate change. Therefore, a study was conducted to investigate the effects of crop residue, nutrient management, and soil moisture on methane (CH4) emissions from maize, rice, soybean, and wheat production systems. In this study, incubation experiments were conducted with four residue types (maize, rice, soybean, wheat), seven nutrient management treatments {N0P0K0 (no nutrients), N0PK, N100PK, N150PK, N100PK + manure@ 5 Mg ha−1, N100PK + biochar@ 5 Mg ha−1, N150PK+ biochar@ 5 Mg ha−1}, and two soil moisture levels (80% FC, and 60% FC). The results of this study indicated that interactive effects of residue type, nutrient management, and soil moisture significantly affected methane (CH4) fluxes. After 87 days of incubation, the treatment receiving rice residue with N100PK at 60% FC had the highest cumulative CH4 mitigation of −19.4 µg C kg−1 soil, and the highest emission of CH4 was observed in wheat residue application with N0PK at 80% FC (+12.93 µg C kg−1 soil). Nutrient management had mixed effects on CH4 emissions across residue and soil moisture levels in the following order: N150PK > N0PK > N150PK + biochar > N0P0K0 > N100PK + manure > N100PK + biochar > N100PK. Decreasing soil moisture from 80% FC to 60% FC reduced methane emissions across all residue types and nutrient treatments. Wheat and maize residues exhibited the highest carbon mineralization rates, followed by rice and soybean residues. Nutrient inputs generally decreased residue carbon mineralization. The regression analysis indicated that soil moisture and residue C mineralization were the two dominant predictor variables that estimated 31% of soil methane fluxes in Vertisols. The results of this study show the complexity of methane dynamics and emphasize the importance of integrated crop, nutrient, and soil moisture (irrigation) management strategies that need to be developed to minimize methane emissions from agricultural production systems to mitigate climate change.

Green synthesis of soybean residue-based nitrogen-chlorine co-doped carbon dots based on deep eutectic solvents: Construction of a PNP fluorescence detection system under the IFE mechanism

How to manage the potential environmental pollution of waste biomass while realizing the resource utilization of the waste is a topic worthy of in-depth investigation. In this paper, after successfully preparing a deep eutectic solvents, we constructed N, Cl-CDs fluorescent probes with high fluorescence yield and biocompatibility by utilizing waste soybean residue as a cheap nitrogen-rich carbon-sourced biomass precursor. The results showed that the fluorescence quenching of N, Cl-CDs has a good linear relationship with the concentration of p-nitrophenol in the range of 0.1–60 μM, with the detection limit of 30 nM, and the fluorescence quenching mechanism was the inner filter effect. This paper demonstrates that the carbon dots fluorescence system has a superior prospect for the highly selective detection of p-nitrophenol, and provides a reliable basis for the future exploration of efficient and environmentally friendly carbon dots synthetic method as well as the economic recycling of waste.

Growing lettuce seedlings in different organic composts used as substrate

Lettuce is the most important vegetable in the world and the most consumed in Brazil. Seedling production with a good quality substrate is very important in the lettuce crop production process. The objective of this study was to evaluate the performance of organic compost substrates in the production of lettuce seedlings. The experiment was carried out in a greenhouse, using polyethylene trays containing 128 trapezoidal cells in a completely randomized design with a 5 × 2 factorial scheme consisting of 5 substrates (commercial substrate; compost I; compost II; compost III; compost IV) and P2O5 supplementation (absent and 0.525 kg m−3 P2O5) and 4 replications. Substrates were produced by composting agro-industrial waste: sawdust, wood shavings and residues from a restaurant, pig litter, cattle manure, residues from the shoot and tubers of sweet potato, soybean residue, and drained bovine ruminal residue. The emergence, plant height, number of leaves, fresh root and shoot biomass, and clod stability of the substrate were evaluated. The substrate formulated from pig litter, cattle manure, and sweet potato (compost II) and pig litter and drained bovine ruminal residue (compost IV) formed seedlings with a greater clod stability of the substrate, plant height, number of leaves, and fresh root and shoot biomass. Substrates based on composting pig litter, cattle manure, and sweet potato (composts II) and pig litter and drained bovine ruminal residue (compost IV) were most suitable for producing lettuce seedlings.

Biogas production performance using soybean residue and hydrothermal pretreated food waste hydrolysate in a continuously anaerobic two-stage pilot plant

In this study, a continuously anaerobic two-stage pilot plant was established for bioenergy production, comprising 5 major pieces of equipment: a mixing tank, 1st anaerobic digester (AD), 2nd AD, sediment tank, aeration tank, and final sediment tank, all operating at ambient conditions. The operation of the continuously anaerobic two-stage pilot plant was automatically controlled by a programmable logic controller (PLC) using a designed control logic concept to set the hydraulic retention time (HRT) and inlet substrate concentration. The organic loading rate, pretreatment of hydrolysis pressure, and microbial community analysis were investigated for their effects on biogas production performance using different substrates: soybean residue (SR) and food waste hydrolysate (FWH), respectively. It was found that the peaks of biogas production rate on daily volumetric feeding were 1.20 m³·m⁻³·d⁻1, and the biogas yield on VS added was 760 dm³·kg⁻1 from food waste hydrolysate with a pretreatment hydrolysis pressure of 10 kg cm⁻2, at an OLR in COD concentration of 3.56 kg m⁻³·d⁻1, and an HRT of 11 days, respectively. The Methanobrevibacter genus was found to be abundant in the 1st AD, approximately 6.7 times more abundant than in the 2nd AD. The continuous anaerobic two-stage pilot plant was properly examined for its application in treating food waste and soybean residue with the goal of obtaining renewable bioenergy.

The Interaction between Adding Soybean Residue and Hydrogel to the Soil on the Mineral Content of Yellow Corn (Zea mays L.) Plants whose Seeds are Treated with Ascorbic Acid

The Interaction between Adding Soybean Residue and Hydrogel to the Soil on the Mineral Content of Yellow Corn (Zea mays L.) Plants whose Seeds are Treated with Ascorbic Acid

Cereal-Legume Mixed Residue Addition Increases Yield and Reduces Soil Greenhouse Gas Emissions from Fertilized Winter Wheat in the North China Plain

Incorporating crop residues into the soil is an effective method for improving soil carbon sequestration, fertility, and crop productivity. Such potential benefits, however, may be offset if residue addition leads to a substantial increase in soil greenhouse gas (GHG) emissions. This study aimed to quantify the effect of different crop residues with varying C/N ratios and different nitrogen (N) fertilizers on GHG emissions, yield, and yield-scaled emissions (GHGI) in winter wheat. The field experiment was conducted during the 2018–2019 winter wheat season, comprising of four residue treatments (no residue, maize residue, soybean residue, and maize-soybean mixed residue) and four fertilizer treatments (control, urea, manure, and manure + urea). The experiment followed a randomized split-plot design, with N treatments as the main plot factor and crop residue treatments as the sub-plot factor. Except for the control, all N treatments received 150 kg N ha−1 season−1. The results showed that soils from all treatments acted as a net source of N2O and CO2 fluxes but as a net sink of CH4 fluxes. Soybean residue significantly increased soil N2O emissions, while mixed residue had the lowest N2O emissions among the three residues. However, all residue amendments significantly increased soil CO2 emissions. Furthermore, soybean and mixed residues significantly increased grain yield by 24% and 21%, respectively, compared to no residue amendment. Both soybean and mixed residues reduced GHGI by 25% compared to maize residue. Additionally, the urea and manure + urea treatments exhibited higher N2O emissions among the N treatments, but they contributed to significantly higher grain yields and resulted in lower GHGI. Moreover, crop residue incorporation significantly altered soil N dynamics. In soybean residue-amended soil, both NH4+ and NO3− concentrations were significantly higher (p < 0.05). Conversely, soil NO3− content was notably lower in the maize-soybean mixed residue amendment. Overall, our findings contribute to a comprehensive understanding of how different residue additions from different cropping systems influence soil N dynamics and GHG emissions, offering valuable insights into effective agroecosystems management for long-term food security and soil sustainability while mitigating GHG emissions.

Fermentation of soybean residue by A. auricula: Mechanisms and uses

The biochemical conversion mechanism of soybean residue by liquid-state fermentation with Auricularia auricula mycelium (AAM) was elucidated through the determination of enzymes and basic nutrients during fermentation as well as the metabolites analysis. The metabolomics analysis was conducted on the differential metabolites of A. auricula using LC-MS/MS and found a total of 351 differential metabolites, including organic acids, sugars, amino acids, phenols etc.; most of which were organic acids, and glycosides. All the differentially expressed compounds were analyzed by KEGG metabolic pathway enrichment. There were 30 metabolic pathways related to the metabolic mechanism of soybean residue conversion; among them, fatty acid synthesis, sugar metabolism, carbon synthesis, and the synthesis of various secondary metabolites were the main metabolic pathways. During the whole fermentation process, the content of flavonoids decreased gradually and its content was 0.001 mg/g after 15 days of fermentation. This indicated that AAM successfully fermented and transformed the soybean dregs into nutritionally rich products. As it was rich in high protein, 3D printing technology was utilized to develop a AAM protein-based cream substitute. The ink exhibited excellent 3D printability owing to its solid viscoelastic behavior. The ink rheology was controlled by XG concentrations, and 3D printed AAM protein emulsion with 2.0% XG showed printing stability. We also produced AAM protein-rich food products using traditional culinary processing techniques. It provided a theoretical basis for realizing the comprehensive utilization of soybean residue and can be used as a new protein source in the food industry with good application prospects.

Nutritional value and fiber content of cookies prepared from okara flour substitution: study on dietary fiber, isoflavone, and chemical properties

Cookies as a popular and ready-to-eat snack began to be developed as an alternative food for people with special diets. Soy products are known to be a source of inexpensive protein, nutritious and have functional properties. Okara as a soybean residue from soymilk production has nutritional value such as protein, fat, antioxidant like isoflavone and others that can be applied to a variety of food such as cookies. The target of this study is to evaluate the fiber and nutritional value of cookies made from okara flour. Prepared cookies are analyzed for proximate, texture, antioxidant and fiber content. This study used ANOVA and followed with Honest Significants Difference (HSD) consisting 3 treatments (A0B0-without substitution of okara flour, A3B2-20% okara flour substitution and 0,5gram cinnamon powder and A4B2-30% okara flour substitution and 0,5gram cinnamon powder). The range of the cookie’s moisture content, ash, crude protein, fat, and carbohydrate was 2.16-4.01%, 1.39-1.65%, 9.1-17.09%, 17.20-21.07%, and 60.24-65.86% respectively. The highest fiber content (3.52%) and isoflavone level (47.4μg/mg) of cookies were cookies prepared with okara flour substitution 30%.

Effects of cover crops and nitrogen fertilization on soil physical properties, carbon and nitrogen fractions, and winter wheat yield in the Chinese loess plateau: A 4-year field experiment

Context or problemLone-term application of chemical fertilizers in farmland ensure adequate or profitable crop yields but may damage soil structure. Cover crops (CCs) have great potentials to improve soil quality and promote sustainable crop production. However, the combined impacts of CCs with nitrogen fertilization on soil quality and crop yields are not clear. Objective or research questionWe aimed to examine the effects of CCs combined with N fertilization rates on soil physical properties, C and N fractions in both bulk soils and aggregates, and crop yields, and to find the best management practice that improve both soil quality and crop yields synthetically. MethodsA 4-year summer CCs - winter wheat field experiment was conducted in the Loess Plateau of China. CCs with different species and combinations (CC) were soybean (SB), sudan grass (SG), a mixture of both (SS), and no cover crop (CK) and N fertilizer (NR) were applied to winter wheat at rates of 0 (N0), 60 (N60), and 120 (N120) kg N ha−1. Soil physical properties and C and N fractions in both bulk soils and aggregates were evaluated at 0–10, 10–20, and 20–40 cm soil depths. ResultsSoil total porosity (TP), saturated water content (SWC), capillary water capacity (CWC), and C and N fractions decreased while bulk density (BD) increased with the increase of soil depth. The CC, NR, and their interaction (CC×NR) had significant effects on soil BD, aggregate size distribution and stability (MWD), and C and N fractions and only CC and CC×NR had significant effects on other physical properties. The incorporation of CCs significantly increased the proportions of > 5 mm aggregates and C and N fractions in both bulk soils and aggregates, especially in 0–10 and 10–20 cm. And SB and SS improved soil other physical properties more than SG, especially in 0–10 cm, which decreased BD by 13.2% and 12.6% while increased TP by 6.5% and 8.3%, SWC by 14.3% and 15.3%, CWC by 13.9% and 14.2%, MWD by 16.6% and 14.4%, respectively, compared to CK. Additionally, soil physical properties improved more with N60 while the C and N fractions in both bulk soils and aggregates increased more with N120. However, BD increased by 2.6% and 3.3% in N60 and N120 than N0, respectively. The correlations between the proportion of macro-aggregates and soil C and N fractions at 0–10 and 10–20 cm indicated the positive effects of CCs on improving soil structure and fertility simultaneously. Aggregated-associated C and N fractions decreased firstly and then increased with the reduced aggregate sizes, and were higher in micro-aggregates than in other size classes. N60-SB increased wheat yields by 98.7% compared with N0-CK. ConclusionsOverall, the incorporation of soybean residue was the best management practice for winter wheat yield and soil fertility under the reduced N fertilization. Implications or significanceThe selection of CCs species should depend on farmland managements, and the appropriate CCs with N fertilizer rates would target the improvements in soil quality, the sequestration of soil organic carbon, and crop yields synergistically.

The Effects of Dietary Fermented Soybean Residue on the Growth, Antioxidant Capacity, Digestive Enzyme Activities, and Microbial Compositions of the Intestine in Furong Crucian Carp (Furong Carp♀ × Red Crucian Carp♂)

An 8-week feeding experiment aimed to investigate the effects of fermented soybean residue in diets on the growth performance, serum antioxidant parameters, intestinal digestive capacity, and microbial composition of the hindgut of Furong crucian carp. The feeds were formulated to contain 0%, 6%, 12%, 18%, and 24% fermented soybean residue (CON, FSR6, FSR12, FSR18, and FSR24, respectively), respectively, to form five diets (crude protein: 33%; crude lipid: 5%). The results showed that incorporating 6% fermented soybean residue into the diet significantly increased the weight gain rate (WGR) and specific growth rate (SGR) and decreased the feed coefficient rate (p < 0.05). Through regression analysis of WGR and SGR, the optimal levels of the dietary fermented soybean residue of Furong crucian carp were determined to be 6.78% and 7.06%. Incorporating fermented soybean residue into the diet decreased the lipid content of the whole body and the levels of glucose, total cholesterol, and triglyceride in the serum of Furong crucian carp. The inclusion of 6% and 12% fermented soybean residue in the diet markedly increased the antioxidant capacity, intestinal amylase activity, and intestinal villous height of Furong crucian carp (p < 0.05). At the 6% level, fermented soybean residue significantly increased the abundance of Romboutsia and Clostridium_sensu_stricto_1 while significantly decreasing the abundance of Vibrio (p < 0.05), indicating that a 6% level of fermented soybean residue was beneficial for intestinal health. In conclusion, incorporating 6–7% fermented soybean residue into the diet of Furong crucian carp was recommended.

Removal of organic matter from tofu wastewater using a combination of adsorption, Fenton oxidation, and ultrafiltration membranes

The production of tofu results in wastewater from the soaking, washing, and pressing processes. Owing to its unique composition and quality, tofu wastewater treatment involves a complex set of challenges. Wastewater from tofu production has a significantly high organic content because it contains many soybean residues and other products. This study aimed to determine the removal efficiency of tofu wastewater contaminants for a combination of adsorption, Fenton oxidation, and ultrafiltration membrane processes. The best strategy for turbidity removal, with a removal value of 99.78%, was an integrated system combining adsorption and ultrafiltration membranes. The most optimal method for reducing organic matter contained in tofu wastewater is Fenton oxidation with TSS, COD and turbidity removal values of 81.11%, 95.13% and 62.42%. Moreover, microphotography analysis using scanning electron microscopy showed an irregularly shaped surface layer with the particles spaced far apart when granular active carbon adsorption was integrated with an ultrafiltration membrane. The results were inversely proportional when Fenton oxidation was integrated with ultrafiltration membranes. After granular active carbon adsorption, the spacing between the granules or crystals increased, whereas the granular dimensions decreased.

New applications of soybean residues in food development

SummarySoybean residue plays an important role in the food industry as a by‐product of soybean processing, especially for functional foods which are beneficial for human health. It can significantly augment the protein, dietary fibre and other crucial nutrients in food products. This fortification process can not only help in regulating blood glucose levels and minimising the risk of obesity but also play an imperative role in offering medicinal benefits to diabetic patients. In the past few years, soybean residues have been found extensive application in functional food items like noodles, cakes, meat products, beverages and seasoning, which have gained significant traction among consumers. Therefore, the utilisation of soybean residues in the food industry presents significant potential for growth and serves as a valuable source of guidance and inspiration for the advancement of functional foods.

Can gypsum and organic amendments achieve sustainability, productivity and maintain soil health under soybean-mustard cropping in sodic soils of western India

Soil salinity is a major environment stress impairing crop production and accelerating soil degradation. Use of soil amendments are practical solutions for altering soil quality to enhance crop productivity in these soils. Hence, we systematically evaluated the impact of soil amendments practices on crop productivity, nutrient use efficiency, soil properties, soil quality index, economics and energetics on soybean-mustard cropping system in sodic Vertisol. In this study, eight treatments comprising of various combinations of soil amendments such as gypsum (@2.5 t ha−1), farmyard manure (FYM@10 t ha−1), crop residue (CR@1.5 t ha−1 of soybean residue during rabi and 3 t ha−1 of mustard residue during kharif season) with recommended fertilizer doses (RNPK) was evaluated in randomized block design with three replications for four consecutive years in soybean-mustard cropping sequences (2016–2019). Results demonstrated that application of gypsum with CR and FYM recorded a significant drop in exchangeable sodium percentage (ESP) (45–48 %), and bulk density (BD) (3–6 %) than that of control. Organic amendment in conjunction with gypsum and chemical fertilizer significantly improved soil chemical, physical and biological properties than that under control and inorganic fertilizer alone treatments. Based on principal component analysis and correlation matrix, minimum data set identified ESP, pH, BD, organic carbon, available nutrients, biomass carbon, calcium content, dehydrogenase as the most important properties controlling soil quality. Integration of RNPK+Gypsum+CR and RNPK+Gypsum+FYM are found superior leading to higher crop yield in soybean (1.23 and 1.21 Mg ha−1 respectively), mustard (1.43 and 1.39 Mg ha−1 respectively), better nutrient recovery efficiency (77 and 53 % respectively), improved soil quality index (0.90 and 0.93 respectively), and higher economic return (benefit: cost ratio-2.88 and 2.1 respectively).Therefore, this study findings highlighted the conjunctive use of gypsum with organic amendments is effective in reclaiming salt stress, improving soil health and crop productivity under oilseed cropping sequence in degraded soils of semi-arid tropics.

The impact of Aspergillus Niger and Neurospora sitophila co-fermentation on the soluble dietary fiber of soybean residue

Soybean residue, as a by-product of soybean, contains over 90% insoluble dietary fiber (IDF) and is underutilized. This study employed Aspergillus Niger and Neurospora sitophila (1:1) as mixed fermentation strains to ferment soybean residues insoluble dietary fiber. Through a single-factor study investigating fermentation time, temperature, and inoculum size, the optimal fermentation conditions for the mixed culture to increase the extraction rate of soluble dietary fiber from soybean residue were explored. After 8 days of fermentation at 22C with an inoculum size of 5%, the extraction rate of soluble dietary fiber reached 38.30%. The fermented soybean residue exhibited a threefold increase in swelling capacity, a 2.5-fold increase in water retention, a 1.56-fold increase in oil retention, and a 1.2-fold increase in oil absorption compared to the unfermented residue. This method provides a research basis for enhancing the extraction rate, obtaining nutritionally rich, and cost-effective soluble dietary fiber from soybean residue.

Comprehensive analysis of soybean residues pyrolysis products

Pyrolysis has been applied to soybean residues from 400 °C to 600 °C to obtain value-added molecules. The biowaste has been previously physicochemically characterized and the temperature effect on products distribution has been evaluated. The results show that the liquid product (bio-oil) reached a maximum yield at 600 °C, while the solid product (bio-char) has a maximum performance at 400 °C. Among the desired products in bio-oil, aromatic hydrocarbons have been improved with the increment of temperature, with a maximum at 550 °C. For non-condensable products, CO2 was the highest emitted compound at all temperatures, together with CO as a consequence of cellulose and hemicellulose thermal decomposition. The minimal CH4 release is caused by the low biomass lignin content. In contrast to previous studies, the majority of the volatile organic compounds (VOCs) released during soybean residue thermal pyrolysis were identified for the first time. Aromatic hydrocarbons were predominant for every temperature, with methylbenzene as the major contributor. The largest relative proportion of aromatics was attained at 450 °C. 2-methylbutanal, 3-methylbutanal and 2-methylfuran were found in this phase as meaningful compounds. As for bio-char, it has shown a higher heating value of 5756 kcal/kg. In this way, it could be considered as a good alternative for power generation. Therefore, the great potential of soybean residue pyrolysis products requires an exhaustive analysis.

PYROLYSIS OF SOYBEAN WASTE: A ROUTE TO BIOCARBON FOR PESTICIDES CAPTURE

Background: This study explores the potential use of biomass residues from soybean pressing via static pyrolysis to produce carbonaceous materials for pesticide adsorption. It emphasizes concerns regarding the environmental impact of agroindustrial waste and the persistent nature of pesticides in soil and water systems. Aims: To investigate the efficacy of biochar obtained from soybean waste in adsorbing pesticides. Specifically, to analyze the gas products generated during pyrolysis and characterize the obtained carbonaceous material for its adsorption capabilities. Methods: Soybean residue underwent static pyrolysis at various temperatures and durations. Gas analysis utilizing FTIR spectroscopy identified the gaseous products generated during the pyrolysis process. The obtained biochar underwent successive washes and characterization through FTIR spectra comparison with commercial activated carbon. Through absorption assays, using UV-VIS spectroscopy, investigations were conducted on the solid biocarbon fractions to evaluate their capacity for absorbing pesticides. Results: Gas Analysis: The study revealed the production of volatile organic compounds (VOCs) and highlighted the prevalence of mono-carbon compounds with increased temperature and pyrolysis time. The analysis demonstrated consistent carbon mass percentages across different reaction conditions. Characterization of Biochar: Comparison with activated carbon indicated structural similarities with heightened intensity in certain bands, suggesting the presence of incomplete cellulose cracking in the obtained biochar. Regarding the Chlorothalonil, Atrazine and DIcamba remotion, notably, the concentration of Chlorothalonil in a 7:3 water: acetonitrile solution decreases by 77 % through adsorption on the carbons. Discussion: The investigation examined the adsorption efficiency of the biochar for Chlorothalonil, Atrazine, and Dicamba from aqueous solutions. Chlorothalonil exhibited substantial retention by the biochar, while Atrazine showed comparatively lower adsorption effectiveness. Remarkably, Dicamba did not demonstrate retention by either the biochar or activated carbon. Conclusion: The study underscores the potential of pyrolyzed soybean waste for pesticide adsorption, particularly highlighting Chlorothalonil's strong affinity with the carbonaceous structure. Further research is needed to optimize adsorption properties and explores potential enhancements of these materials through additional treatment methods, offering promising avenues for environmental remediation.

Revealing the generation of reactive oxygen species in hydrochar and pyrochar: Insight into rational regulation of free radicals and catalytic mechanism

The removal of organic pollutants by biochar has been extensively studied. However, the differences in the removal mechanisms of contaminants by biochar obtained from different preparation techniques have not been thoroughly elucidated. In this study, the catalytic performances of hydrochar (HC) and pyrochar (PC) were compared in the dark and light. Owing to more persistent free radicals (PFRs), greater defects and stronger charge transfer ability on the surface, PC could produce a certain concentration of superoxide radicals (•O2−) even in the dark, making its degradation efficiency for benzoic acid (BA) 11% higher than that of HC. On the contrary, when the light was turned on, HC rather than PC can generate a higher amount of hydroxyl radical (•OH), resulting in an 11% higher degradation efficiency of BA compared to PC. The improvement of catalytic performance in HC originated from its oxygen-containing functional groups (OFGs), which was beneficial for its effective production of singlet oxygen (1O2) and ·OH under light exposure. For PC, its photocatalytic activity depended mainly on the formation of 1O2 induced by the triplet of DOM (dissolved organic matter), but the lack of oxidative ·OH in its system leads to a lower degradation efficiency than that of HC. To prove the universal applicability of this rule for biochar materials, HC and PC materials obtained from soybean residue were also prepared for degrading BA. This work is devoted to an in-depth exploration of the catalytic activation mechanism of biochar obtained by different technological methods, and can create conditions for the generation of more dominant reactive oxygen species (ROS) on biochar, thus providing the guidance for environmental remediation.

Impact of Ganoderma lucidum fermentation on the nutritional composition, structural characterization, metabolites, and antioxidant activity of Soybean, sweet potato and Zanthoxylum pericarpium residues

One of the major issues in the food sector is the lack of resource utilization and the contamination of the environment caused by by-products. This study aimed to investigate the effects of Ganoderma lucidum (GL) fermentation on the nutritional components, structural characterization, metabolites, and antioxidant activity of soybean residue (SR), sweet potato residue (SPR), and zanthoxylum pericarpium residue (ZPR). The results showed that the nutrient contents of SR, SPR and ZPR increased. The active substances, amino acids (umami, aromatic and basic), metabolites and antioxidant activity (DPPH, ABTS, FRAP) (SR and SPR increased by 11.43, 32.64, 40.19 μmol Trolox/100 g and 19.29, 17.7, 32.35 μmol Trolox/100 g, respectively) of SR and SPR were increased. However, the results of ZPR showed a decrease in the content of bioactive substances, amino acids, and antioxidant activity. The results show that using GL fermentation can provide novel ideas and theoretical basis for improving SR and SPR to obtain new raw materials for antioxidant products.

Isoflavone aglycone-rich powder from soybean residue submerged fermentation using Lactobacillus fermentum 44197

Soybean residue contains high amounts of isoflavones and proteins with utilisation limited to animal feed and fertiliser. This study investigated isoflavone bioconversion by Lactobacillus fermentum 44197 to enhance the biological activity of fermented soybean residue to serve as a functional food ingredient. Using liquid-state fermentation, growth of L. fermentum 44197 in soybean residue substrate was similar to growth in MRS substrate. β-Glucosidase produced by L. fermentum 44197 contributed to isoflavone bioconversion from glycosides to aglycones. Submerged fermentation in substrate containing 20% soybean residue and 4% glucose at 37 °C for 24 h produced the highest isoflavone aglycones (daidzein and genistein). Fermented soybean residue was dried by drum drying and exhibited high isoflavone contents (mg/100 g db): daidzin (2.24), genistin (5.33), daidzein (28.62) and genistein (66.07) that was named isoflavone aglycone-rich powder. The powder was an excellent source of isoflavone aglycones, protein and free amino acids, exhibiting high protein solubility between pH 3 and 9 and high water absorption (4.0 g/g). Results demonstrated the potential of L. fermentum 44197 for isoflavone bioconversion of soybean residue under submerged fermentation. Isoflavone aglycone-rich powder can also be used for bioactive compound enrichment and formulation of various functional foods and health foods, especially plant-based protein products.