Substrate Fermentation Research Articles

Use of cactus pear pruning waste to improve soil properties and to produce high-quality compost

Bio-fertilizers could be a possible solution to help manage bio-waste problems and to maintain soil health conditions, especially in organic farms. Pruning of cactus pear produces from 6 to 10 tons/yearly of cladodes per hectare in specialized Italian orchards, which represents waste and a cost for disposal to farmers. Therefore, the aim of the work was to investigate the effects on soil physical properties, microflora activity, and basil plant growth of powdered pruning waste from cactus pear incorporated in the soil (10%, 20%, 30% 40% w/w). Moreover, we studied a dynamic composting process from fresh cladodes to produce stabilized end-products at the farm level. Our studies demonstrated that holding water ability and bulk density of soil were ameliorated by supplementing dried cladodes. Thus, gravitational and gravimetric water was positively correlated with the increase of added dried cladode in the soil (0.1% and 6.2 g H2O ± 0.3 in samples of 40% mixed soil versus 68% and 3.3 g H2O ± 0.3 in control). Furthermore, bulk density was reduced limiting soil compaction. Preliminary results on microbial activity suggested a possible selection/inhibition of some bacterial strains correlated with the increment of dry cladode supplementation. The basil plants grown in 20% mixed soil showed an increased biomass when compared to the control (+ 21%). Finally, raw cladode proved to be an excellent substrate for aerobic fermentation providing a final product of good quality and high moisture content (65%). These results are particularly relevant in organic agriculture where bio-fertilizers are recommended as economical, eco-friendly solution accessible also to marginal and small farms.

Variation of the Content and Antioxidant Activity of Active Substances in the Kombucha Fermentation of Mulberry Leaves

With the increasing emphasis on healthy living, Kombucha beverages are becoming more and more popular. Recently, fermented Kombucha with different materials and investigated the efficacy have become hot topics. In this paper, mulberry leaves were used as substrates for Kombucha fermentation. The active substances contents and antioxidant activities of the fermented mulberry leaf infusion were significantly enhanced. After being fermented for 10 days, the total phenolic substances and total flavonoids in the Kombucha fermented mulberry leaf infusion were 7.38 and 12.24 times higher than those in the unfermented mulberry leaf infusion, respectively. While the mulberry leaf infusion that fermented for 6 days had the highest antioxidant capacity. The Ferric (Fe3+) reducing power, ABTS+ radical scavenging capacity, and hydroxyl radical (·OH) scavenging capacity were enhanced by 90.3%, 21.82%, and 46.2%, respectively. In conclusion, after being fermented by Kombucha, the antioxidant properties of mulberry leaf infusion were significantly improved, which will contribute to expanding the subsequent development and application of mulberry leaf.

Efficient bio-hydrogen production by dark co-fermentation of food-rich municipal solid waste and urban pruning wastes of pine, cypress, and berry

Bio-hydrogen (bio-H2) production from dark co-fermentation of pruning wastes, from pine, cypress, and berry trees, and food-rich municipal solid waste (FMSW) was evaluated as a promising way to combine waste management and renewable energy production. The inoculum was initially optimized by heat-shock pretreatment at 65, 75, 85, and 95 ℃ for 15, 30, and 45 min to maximize bio-H2 yields. The optimum pretreatment conditions (75 °C for 45 min) were applied for dark co-fermentation analyses. The highest bio-H2 production yield of 84 ± 6 mL/g VS was obtained by dark co-fermentation of 20 g/L pruning wastes and FMSW under initially neutral conditions. The fermentation of individual substrates led to 40.9, 0.2, 0.1, and 0.2 mL/g VS from FMSW, pine, berry, and cypress, respectively, 85% lower than that obtained through dark co-fermentation. Therefore, co-processing of a “stiff substrate”, lignocellulose, with a “loose part”, starchy FMSW, leads to a higher bio-H2 yield. Dark co-fermentation led to the bio-conversion of more than 76% of starch, 31% of glucan, and 41% of hemicellulose, besides 41% lignin removal. The modified Gompertz model (MGM) and Logistic model (MLM) were well-fitted on kinetic data (with R2 values ≥0.98), and the kinetic parameters were calculated.

Kombucha as a Health-Beneficial Drink for Human Health.

Kombucha is a unique fermented beverage made from a symbiotic culture of yeast and bacteria. Kombucha is normally based on black tea added to water, then sugar is added as a substrate for fermentation in this beverage. This unique beverage is composed of amino acids, flavonoids, vitamins, and some active enzymes. Several beneficial health effects such as antioxidant, antimicrobial effects have been reported as a result of probiotics and prebiotics presence. These health effects of kombucha are attributed to its bioactive chemical and biological agents of probiotics bacteria e.g., Gluconobacter, Acetobacter and yeasts like Saccharomyces sps., along with glucuronic acid as the main sources of the health protection. This review focuses on the beneficial effects of Kombucha including antimicrobial, antioxidant, anti-cancer antidiabetic properties, as well as liver protection, treat of gastrointestinal problems, AIDS, gastric ulcers, obesity (and energy production), detoxification, and skin health.

Production of Vanillin from Pineapple Peels Using Alkaline Hydrolysis and Microbial Fermentation

Vanillin is one of the most commonly utilized aromatic flavoring chemicals in the food and cosmetics industries. It is derived from natural sources, making it more expensive than synthetic vanillin, and it constitutes less than one percent of the annual market demand. Pineapple peel stands out as a valuable source for extracting ferulic acid, which in turn is utilized in the synthesis of vanillin. As a result, researchers are exploring alternative methods for producing vanillin, such as biotechnological production from ferulic acid. In this study, the capability of pineapple peels as a substrate for the microbial fermentation of ferulic acid by Aspergillus niger to produce vanillin in a single step was investigated. The biotransformation of ferulic acid from pineapple peel by alkaline hydrolysis was optimized using different concentrations of NaOH. Further, the detection and quantification of vanillin and ferulic acid were carried out using High-Performance Liquid Chromatography and thiobarbituric acid (TBA) method. Through HPLC analysis, the amount of vanillin concentration produced from the supernatant culture was 1.47±0.24 µg/ml from 1.0 M NaOH concentration and 2.83±0.44 µg/ml from 2.0 M NaOH concentration. From this study, 57.09±1.84 µg/ml and 83.84±4.01 µg/ml of ferulic acid were produced from the 1.0 M NaOH and 2.0M NaOH, respectively. In addition, using the TBA technique, vanillin concentrations were calculated, resulting in 12.92 ± 0.54 µg/ml and 15.38 ± 0.77 µg/ml from 1.0 M and 2.0 M NaOH concentrations, respectively. Briefly, the pineapple peel has been discovered as a good source for vanillin production using Aspergillus niger in the fermentation method.

Antioxidant and Anthocyanin-Rich Vinegar Fermented from Thai Colored Rice Varieties

This study aims to produce antioxidant and anthocyanin-rich vinegar using three types of Thai rice through surface culture fermentation (SCF). Three varieties of Thai rice with different colors, including Khao Dawk Mali 105 (white color), Sangyod (brown color) and Hom Nil (black color), were used as a substrate for vinegar fermentation. The different Thai rice varieties were hydrolyzed by boiling and enzymatic hydrolysis. The sweetness of the hydrolyzates was adjusted by adding granulated sugar at 20 °Brix and using it as a substrate. A mixed culture of Saccharomyces cerevisiae var. burgundy and S. cerevisiae var. kyokai was used as a yeast starter for alcohol fermentation. After 4 weeks of fermentation, Acetobacter aceti TISTR 354 required only 10 days to convert alcohol into acetic acid by the surface-culture fermentation method. Vinegar produced from the Thai rice varieties contained acetic acid at a concentration of more than 4.0 % (v/v), with residual alcohol concentrations less than 0.5 % (v/v). Hom Nil vinegar presented an anthocyanin content of 2.39 ± 0.44 mg/L and had the highest antioxidant activity, with 428.47 ± 4.04 g/mL (Total phenolic content; TPC), 71.80 ± 0.00 g/mL (Ferric reducing antioxidant power assay; FRAP), and 49.27 ± 0.27 % inactivation (2,2-Diphenyl-1-picrylhydrazyl; DPPH). A sensory panel rated the vinegar fermented from the three varieties as ‘like slightly’ on a 9-point hedonic scale. HIGHLIGHTS Three distinct Thai rice varieties, each with unique colors (white, brown, and black), were utilized as substrates for vinegar fermentation Hydrolysis of the rice substrates involved boiling and enzymatic processes, with sweetness adjusted using granulated sugar at 20 °Brix A mixed culture of cerevisiae var. burgundy and S. cerevisiae var. kyokai served as a yeast starter for alcohol fermentation The innovative surface-culture fermentation method employed Acetobacter aceti TISTR 354, converting alcohol into acetic acid in just 10 days Hom Nil rice vinegar exhibited remarkable attributes, with an anthocyanin content of 2.39 ± 0.44 mg/L and exceptional antioxidant activity (428.47 ± 4.04 g/mL TPC, 71.80 ± 0.00 g/mL FRAP and 49.27 ± 0.27 % DPPH inactivation) Sensory evaluation by a panel yielded a ‘like slightly’ rating on a 9-point hedonic scale for vinegars derived from all 3 rice varieties GRAPHICAL ABSTRACT

Temporal changes in the fermentation characteristics, bacterial community structure and the functionality of the predicted metagenome of a batch fermenter medium containing the upper gastrointestinal enzyme resistant fraction of white sorghum (Sorghum bicolor L. Moench)

Sorghum is a potential prebiotic ascribed to the high native resistant starch (RS) content. Our previous studies on raw sorghum have revealed prominent amino acid fermentation despite the high RS content. Interestingly, autoclaved-freeze-dried sorghum fed rats exhibited beneficial microbial and biochemical profiles. Having a keen interest to reciprocally scrutinize the underlying mechanisms behind these contrasting outcomes, we used an in vitro porcine batch fermentation model. The fermentable substrates in raw and autoclaved-freeze-dried (three cycles) sorghum (AC) after in vitro gastrointestinal digestion fostered similar bacterial community structures, yet with significant differences in the characteristic amylolytic microbial taxa abundance and their temporal variation. Further, significant differences in the concentration of organic acids in raw and AC manifested the differences in the predicted abundance of the underlying pathways of carbohydrate and organic acid metabolism. Thus, this study highlights the propensity of the heat-moisture treatment of sorghum in modifying the fermentability of its RS.

Protective Mechanism of Rosa roxburghii Tratt Fermentation Broth against Ultraviolet-A-Induced Photoaging of Human Embryonic Skin Fibroblasts.

This study takes the fruit of Rosa roxburghii Tratt (RRT) as a fermentation substrate and carries out a quantitative visual analysis of the domestic and foreign literature on screenings of five different lactic acid bacteria to obtain a fermentation broth. Systemic anti-photoaging effects are analyzed at the biochemical, cellular, and molecular biological levels. DPPH and ABTS free radical scavenging activities are used to verify the antioxidant capacity of the RRT fruit fermentation broth in vitro. Human embryonic skin fibroblasts (HESs) are used to establish a UVA damage model, and the antioxidant capacity of the RRT fruit fermentation broth is verified in terms of intracellular reactive oxygen species (ROS) and antioxidant enzyme activity. RT-qPCR and ELISA are used to detect the expression of TGF-β/Smad, MMPs, and the MAPK/AP-1 and Nrf2/Keap-1 signaling pathways in order to explore the anti-oxidation and anti-photoaging effects of the RRT fruit fermentation broth by regulating different signaling pathways. The results show that an RRT fruit fermentation broth can effectively protect cells from oxidative stress caused by UVA and has significant anti-photoaging effects, with the co-cultured Lactobacillus Yogurt Starter LYS-20297 having the highest overall effect.

A Chiral-LC-MS Method for the Simultaneous Quantification of Short-Chain Fatty Acids and D/L-Lactate in the Ruminal Fluid of Dairy Cows.

Short-chain fatty acids (SCFA) and lactate in ruminal fluid are products resulting from the microbial fermentation of substrates and can be used to reflect the composition and activity of the ruminal microbiome. Determination of SCFA and D-/L-lactate in ruminal fluid currently requires two separate protocols, which is time-consuming and costly. In this study, we have optimised and validated a simple and unified 3-nitrophenylhydrazine (3-NPH) derivatisation protocol and a 20 min chiral-LC-MS method for the simultaneous quantification of all SCFA and D- and L-lactate in ruminal fluid. This method, which requires no sample pretreatment or purification shows adequate sensitivity (limit of detection (LOD): 0.01 µg/mL), satisfactory accuracy (recovery: 88-103%), and excellent reproducibility (relative standard deviation (RSD) for repeated analyses < 3% for most analytes). The application of this method to a cohort of 24 animals allowed us to reveal a large inter-cow variation in ruminal SCFA and lactate level, the concentration range for each species, the widespread correlation between different SCFA, and the strong correlation between D- and L-lactate.

Performance evaluation of Trichoderma reseei in tolerance and biodegradation of diuron herbicide in agar plate, liquid culture and solid-state fermentation.

The present study evaluated the performance of the fungus Trichoderma reesei to tolerate and biodegrade the herbicide diuron in its agrochemical presentation in agar plates, liquid culture, and solid-state fermentation. The tolerance of T. reesei to diuron was characterized through a non-competitive inhibition model of the fungal radial growth on the PDA agar plate and growth in liquid culture with glucose and ammonium nitrate, showing a higher tolerance to diuron on the PDA agar plate (inhibition constant 98.63 mg L-1) than in liquid culture (inhibition constant 39.4 mg L-1). Diuron biodegradation by T. reesei was characterized through model inhibition by the substrate on agar plate and liquid culture. In liquid culture, the fungus biotransformed diuron into 3,4-dichloroaniline using the amide group from the diuron structure as a carbon and nitrogen source, yielding 0.154mg of biomass per mg of diuron. A mixture of barley straw and agrolite was used as the support and substrate for solid-state fermentation. The diuron removal percentage in solid-state fermentation was fitted by non-multiple linear regression to a parabolic surface response model and reached the higher removal (97.26%) with a specific aeration rate of 1.0 vkgm and inoculum of 2.6 × 108 spores g-1. The diuron removal in solid-state fermentation by sorption on barley straw and agrolite was discarded compared to the removal magnitude of the biosorption and biodegradation mechanisms of Trichoderma reesei. The findings in this work about the tolerance and capability of Trichoderma reesei to remove diuron in liquid and solid culture media demonstrate the potential of the fungus to be implemented in bioremediation technologies of herbicide-polluted sites.

Optimization of Conjugated Linoleic Acid and Eicosapentaenoic Acid Production from Sesame Waste by Response Surface Methodology

Conjugated linoleic acid (CLA) and eicosapentaenoic acid (EPA) have been recognized for their physiological functions and potential as dietary supplements. This study is aimed at investigating the production and enhancing the efficiency of these two acids from Lactiplantibacillus plantarum using sesame waste as a natural, cost-effective, and readily available culture medium. Response surface methodology (RSM) was employed to optimize the production of CLA and EPA in a solid bed system using sesame waste paste as the fermentation substrate. The main processing parameters, including three humidity levels (60%, 70%, and 80%), three inoculum percentages (2%, 4%, and 6% v/v), and three fermentation temperatures (30°C, 37°C, and 44°C), were optimized. An experiment was conducted to validate the determined conditions, and a strong correlation was observed between the experimental results and the predictions made by the software. The optimal conditions for CLA and EPA production were determined to be an inoculation level of 6% with 80% humidity and at 37°C. Gas chromatography analysis of the fermented sesame waste medium revealed that the highest yields of CLAc9t11 and CLAt10c12, as well as eicosapentaenoic acid, were obtained in the medium fermented with 80% humidity and 6% inoculation at 37°C. The respective percentages of these fatty acids in the total fatty acid composition were found to be 0.351% (w/v) and 0.1% (w/v) for CLA and 0.139% (w/v) for EPA under the optimized conditions. These findings contribute to the understanding of CLA and EPA production and highlight the potential of L. plantarum and sesame waste as a fermentation substrate for their efficient production.

The Biotransformation and Influence on the Functional Activities of Metabolites during the Fermentation of Elaeagnus moorcroftii Wall.ex Schlecht. Juice by Bifidobacterium animalis subsp. lactis HN-3.

Elaeagnus moorcroftii Wall.ex Schlecht. (EWS) has extensive nutrients and functional active ingredients, which makes it an excellent potential substrate for fermentation. The improvement in the antioxidant activity of Elaeagnus moorcroftii Wall.ex Schlecht. juice (EWSJ) fermented by Bifidobacterium animalis subsp. lactis HN-3 (B.an3) could be attributed to the metabolism and biotransformation of plant-based products by the bacterial strain. To reveal the underlying mechanism, non-targeted metabolomics was applied in this study. After fermentation, the structure of downregulated carbohydrates, amino acids, fatty acids, and flavonoids was changed by Bifidobacterium biotransformation (included four reductions, three hydrolyses, four isomerizations, three deglycosidations, and five other reactions). The structure of these converted upregulated products has a higher antioxidant ability to reduce free radicals than their precursors, such as the flavonoids in the form of hydrolyzed conjugates, amino acids with multiple sulfhydryls or hydroxys, carbohydrates with reactive oxygen on benzene rings and fatty acids with unsaturated bonds, short chains, and glycosides. These findings shed light on the mechanism of the metabolism and biotransformation of EWSJ by B.an3, facilitate the study of the interaction between probiotics and fermented plant-based products, and provide a theoretical basis for the development of Bifidobacterium-fermented plant products with stronger functional activities.

Quality and flavor development of solid-state fermented surimi with Actinomucor elegans: A perspective on the impacts of carbon and nitrogen sources

The influence of four carbon and nitrogen substrates on the quality and flavor of a novel surimi-based product fermented with Actinomucor elegans (A. elegans) was investigated, with a focus on carbon and nitrogen catabolite repression. The results showed that the substrate significantly affected mycelial growth, enzyme activities, and the metabolites of A. elegans. Although glucose significantly promoted A. elegans growth by 116.69%, it decreased enzyme secretion by 69.79% for α-amylase and 59.80% for protease, most likely by triggering the carbon catabolite repression pathway. Starch, soy protein, and wheat gluten substantially affected the textural properties of the fermented surimi. Furthermore, wheat gluten significantly promoted the protease activity (102.70%) and increased protein degradation during surimi fermentation. The fishy odor of surimi was alleviated through fermentation, and a correlation between the volatile compounds and A. elegans metabolism was observed. These results explore fermentation substrates in filamentous fungi metabolism from a catabolite repression perspective.

Optimization and characterization of laccase (LccH) produced by Hexagonia hirta MSF2 in solid-state fermentation using coir pith wastes (CPW)

The accumulation of coir pith waste, a byproduct of coconut husk processing, poses environmental and logistical challenges. An innovative and sustainable solution involves using coir pith as a substrate for solid-state fermentation (SSF). In SSF, coir pith can be converted into valuable products, such as enzymes, organic acids, and bioactive compounds. The present study aimed to evaluate laccase production by Hexagonia hirta MSF2 through SSF using the coir pith waste as substrate. Physico-chemical parameters like moisture, pH, temperature, C source, N source, and CuSO4 concentrations were pre-optimized, and optimized through RSM. Laccase activity of 1585.24 U g−1 of dry substrate was recorded by H. hirta MSF2 on coir pith containing 1 % C source, 0.5 % N source, 0.25 mM of CuSO4 concentration, moisture content of 75 % at pH 4.6 and temperature 28 °C. Subsequently, the enzyme extraction parameters including, extraction buffer, mode of extraction, and temperature were optimized. The molecular weight of laccase was 66 kDa as observed by SDS-PAGE and native-PAGE. The optimum activity of partially purified laccase was achieved at 40 °C, and pH 4.0. Increasing salt concentration and use of different inhibitors affected the laccase activity. Organic solvents like dimethyl sulphoxide (DMSO) and methanol, and metal ions like BaCl2, CaCl2, CuSO4, and MnCl2 stimulated the laccase activity. Hence, coir pith used in SSF offers a dual benefit of waste management and enzyme synthesis through an eco-friendly and cost-effective approach.

Production of chitosan-based composite film reinforced with lignin-rich lignocellulose nanofibers from rice husk

Lignocellulosic nanofibers (LCNFs), implying lignin-containing cellulose fibers, maintain the properties of both lignin and cellulose, which are hydrophobic and hydrophilic, respectively. The presence of hydrophobic lignin in LCNFs is expected to be an economical and attractive option that can improve the thermal and mechanical properties of polymers. Thus, this study was conducted to produce lignin-rich LCNFs from sugar-rich waste obtained from rice husks after acidic pretreatment. The LCNFs were produced from the lignin-rich solid fractions obtained after pretreatment and enzymatic hydrolysis, which were then incorporated as an additive into a chitosan-based film. The variations in lignin content in the range of approximately 50.6%–66.8% in differently obtained LCNFs gave significantly different optical strengths and mechanical properties. These controllable processes may allow for customized film formation. Additionally, the glucose-rich liquid fractions obtained after pretreatment and enzymatic hydrolysis were used as a substrate for ethanol fermentation to achieve total utilization of rice husk biomass waste. In conclusion, the lignin-rich biomass fraction holds promise as a suitable material for chitosan-LCNF film and has the potential to increase the economic feasibility of the biomaterial industry.

Employing soil isolated fungi for production of bioactive phenolic compounds: a fermentative approach

An efficient method of solid-state fermentation (SSF) is reported for producing bioactive phenolic compounds using soil-isolated fungi. Antioxidant activity using a rapid DPPH (1,1-diphenyl-2-picryl hydrazyl), was employed to screen the 120 fungal isolates from soil. Aspergillus terreus 1, Aspergillus fumigatus, Aspergillus terreus 2, Penicillium citrinum, Aspergillus wentii1, Aspergillus wentii 2, Penicillium expansum and Penicillium granulatum were chosen, concerning their antioxidant activity and total phenolic content. These fungal strains were applied on agro residues viz. sugarcane bagasse, corn cob, rice straw, pea pod and wheat straw, to evaluate the release of phenolic compounds. The fermented extracts from various agro-residues showed good antioxidant activity against DPPH, ferric ion, and nitric oxide radicals. The highest antioxidant activity was observed in fermented extracts of sugarcane bagasse, followed by pea pod. Additionally, the total phenolic content in the fermented extracts positively correlated with antioxidant potential. This study highlights the significant potential of solid substrate fermentation using soil-isolated fungi and agro-residues to produce bioactive phenolic compounds with potent antioxidant properties. The utilization of SSF for the extraction of bioactive compounds from natural sources not only offers a clean and sustainable approach but also contributes to the valorization of agro-industrial residues.

The Substitution of Fishmeal with Yeast Culture in the Yellow Catfish (Pelteobagrus fulvidraco) Diet: Growth, Serum Biochemical Indices, and Intestinal and Hepatopancreatic Histology.

Yeast culture is a complex fermentation product consisting of fermentation substrate, yeast cells and their metabolites. This study investigated the potential of yeast culture in replacing fishmeal in the diet of yellow catfish (Pelteobagrus fulvidraco). First, a basal diet was formulated to contain 160 g/kg fishmeal (CON), and then the dietary fishmeal was decreased to 120, 80, 40 and 0 g/kg via yeast culture inclusion, respectively, to form another four isonitrogenous and isolipidic diets (YC-12, YC-8, YC-4 and YC-0). Yellow catfish (3.00 ± 0.10 g) were fed with the above five diets with triplicates per treatment and 40 fish per replicate. After 8 weeks of feeding, the weight gain (WG), protein efficiency rate and protein retention in the YC-12 group and the feed conversion ratio (FCR) in the YC-12 and YC-8 groups showed no significant differences to the CON group (p > 0.05), but the WG in the YC-8, YC-4 and YC-0 groups was significantly lower, and the FCR in the YC-4 and YC-0 groups was significantly higher than in the CON group (p < 0.05). In terms of the whole-body composition, only the crude lipid content in the YC-0 group decreased significantly (p < 0.05). Compared with the CON group, the aspartate aminotransferase and alanine aminotransferase activities and D-lactic acid content in the YC-0 group were significantly increased, and the total cholesterol content was significantly reduced (p < 0.05). The activities of catalase, superoxide dismutase, and alkaline phosphatase, as well as the content of complement C3 and immunoglobulin M, were significantly increased, while the MDA content was significantly reduced in the YC-12 and YC-8 groups (p < 0.05). There were no significant differences in the intestinal amylase and lipase activity among all the groups (p > 0.05), while the trypsin activity in the YC-12 and YC-8 groups, as well as the diamine oxidase in the YC-4 and YC-0 groups, were significantly higher than those in the CON group (p < 0.05). In the intestine histology, there was a significant decrease in the intestinal villus height in the YC-4 and YC-0 groups as well as in the villus width in the YC-0 group (p < 0.05). In the hepatopancreas histology, lipid droplets appeared in the YC-4 and YC-0 groups, and severe cell vacuolation was observed in the YC-0 group. As a summary, in a practical diet containing 160 g/kg fishmeal, yeast culture can effectively replace 40 g/kg fishmeal without negatively affecting the growth performance, nutrient utilization, serum immune and antioxidant, intestinal and hepatopancreas histology of yellow catfish.

Mechanism of improving anaerobic fermentation performance of kitchen waste pretreated by ionizing irradiation-part 1: rice.

Ionizing irradiation, as a new pretreatment method for the anaerobic fermentation of organic pollutants, is featured with fast reaction speed, good treatment effect, no need to add any chemical reagents, and no secondary pollution. This study explores the mechanism of improving anaerobic fermentation performance of rice samples pretreated by cobalt-60 gamma irradiation through the influence on fermentation substrate, acidogenic phase and methanogenic phase. The results reveal that the soluble chemical oxygen demand of the irradiated rice sample at an absorbed dose of 9.6 kGy increases by 12.4 times due to the dissolution of small molecules of fat-soluble organic matter. The yield of biogas in the acidogenic phase increases by 22.2% with a slight increase in hydrogen gas content. The yield of biogas and methane gas content in the methanogenic phase increases by 27.3% and 15%, respectively. Microbial genome analysis, performed with MiSeq high-throughput sequencing and metagenomic methods, suggests the microbial abundance and metabolic functions in the anaerobic fermentation process change significantly as a result of the pretreatment by gamma irradiation.

Biological transformation of medicine and food homology hawthorn with Monascus ruber to enhance lipid-lowering function

Obesity and hyperlipidemia, chronic diseases resulting from excessive energy intake and abnormal lipid metabolism, respectively, are intricately associated with cardiovascular disease and diabetes and have become global health problems. Monascus ruber (M. ruber), a filamentous fungus with edible properties, produces bio-functional metabolites including a good deal of enzymes. In this study, the effect of the biological transformation of fermented food on obesity and hyperlipidemia, was systematically investigated using the mixture of medicine and food homology (MFH) hawthorn and millet as fermentation substrate. Results showed that fermentation promoted the release of bioactive compounds such as phenolic compounds. Pancreas lipase assay indicated that the inhibition rate and IC50 of free phenolic compounds in fermented MFH food were 70.51% ± 2.59%, and 1.34 mg/mL, respectively. In vitro, the binding rates of free phenolic compounds in fermented MFH food to Sodium cholate (SC), sodium glycinate (SGC) and sodium taurocholate (STC) were 84.99% ± 6.59%, 80.29% ± 6.23%, and 79.68% ± 6.18%. Further, Monascus-fermented hawthorn and millet (MFHM) of fermented MFH food markedly suppressed lipid accumulation in oleic acid (OA)-induced HepG2, with cell triglycerides (TG) and total cholesterol (TC) clearance of 24.31% ± 1.81% and 73.88% ± 2.72%, respectively. These findings implied that the fermentation of a mixture of MFH millet and hawthorn by M. ruber holds promise for reducing obesity and lowering lipid levels, thereby serving as a valuable foundation and reference for future research on the development of multifunctional food products.

Antihypertensive effects of condiments prepared from fermented legumes: A review

The prevalence of hypertension has been increasing over the years. Thus, dietary guidelines focusing on the reduction of daily sodium intake are introduced. The association between the intake of condiments, one of the major sources of dietary sodium, and the prevalence of hypertension has been investigated. Regardless of high sodium content, condiments prepared from fermented legumes exert antihypertensive effects instead of increasing the risk of hypertension. Considering the hypotensive potency of legume-based condiments, modifications including reduction or removal of sodium content, incorporation of high protein fermentation substrate, changing of fermentation conditions, and selection of different microbial strains have been carried out to enhance their antihypertensive effects. The elevated antihypertensive activity of legume-based condiments is mainly associated with the increment of angiotensin-converting enzyme (ACE) inhibitory peptides formed during fermentation. The precise mechanisms of legume-based condiments in regulating blood pressure are complex and yet to be validated. Considering the antihypertensive potential of legume-based condiments, the present review paper aimed to summarise and elaborate their antihypertensive effects.