Fermentation Temperature Research Articles

Mathematical modeling as a tool in kombucha beverages bioactive quality control

This study examined the application of mathematical models on total flavonoids content and sensory mark of kombucha beverages on winery effluent. Process parameters were as follows: 0, 3, 6 and 9 days of fermentation time; 20, 25 and 30 ?C of fermentation temperature and 3, 5 and 7% of initial total reducing sugars. Total flavonoids were determined spectrophotometrically and sensory mark by a descriptive test and five points category scale. Total flavonoids content decreased during the applied kombucha fermentation process, which lasted for 9 days. On average, total sensory mark suggested that consume kombucha products are obtained after 3 days of the fermentation, regardless on the fermentation temperature or sugars content. In order to produce kombucha beverage with the highest bioactive quality, response surface methodology proposed the following process parameters: 3 days of fermentation, 7% of initial total sugars and 30?C process temperature.

ИСПОЛЬЗОВАНИЕ КОНСОРЦИУМА МИКРООРГАНИЗМОВ ГРАНУЛ ВОДНОГО КЕФИРА ДЛЯ ПОЛУЧЕНИЯ НАПИТКА

In food industry, fermentation is defined as the process of converting organic substances into acids, ethanol or carbon dioxide. These substances are capable of suppressing the growth of pathogenic microorganisms in the products. The main substrates used in the production of fermented foods are milk, meat, fish, cereals, fruits, vegetables and beverages. Currently, fermented foods and beverages are considered as a part of daily diet. Our current research results showed that the fermentation temperature, sugar concentration and carrot juice concentration affected the dry matter content and sensory properties of the finished drink. The maximum amount of dry substances was noted in the beverage samples obtained at a temperature of 25°C with a content of 10% sucrose, fermentation time of which was 24 hours. After 48 and 72 hours of fermentation, the dry matter content decreases by 0.5 and 1%, respectively. The most optimal samples in terms of taste and dry matter content were samples of a drink containing 10% sugar and 10% carrot juice, fermented at a temperature of 25°C for 48 hours, while the shelf life of the drink, taking into account the survival of microorganisms, was 5 days.

Investigation of optimal parameters for aspartic protease production from Aspergillus terreus using solid-state fermentation

The current study presents extracellular Aspartic protease production using low-cost agro-industrial waste with the indigenously isolated novel strain Aspergillus terreus, and parameters that largely affect enzyme production, namely fermentation time, pH, moistening solution, temperature, inoculum volume, and different solutions, were utilized for enzyme extraction. The isolated fungus was identified as A. terreus (registered as A. terreus SFH5 in the gene bank) by phenotypic and molecular characterization, showed the highest aspartic protease activity of 258.6 units/mL and 272.2 units/mg using a solid-state fermentation technique during screening, and was further used for media component screening and optimization studies. The study employed wheat bran as the preferred production medium and casein as the nitrogen source. The fermentation process was conducted at a temperature of 30°C and a pH of 5. The moistening solution to fermentation medium ratio was set at 3:1, while an inoculum volume of 2 mL (containing 1 × 106 spores/10 g solid) was used. Distilled water was selected as the most effective solution for extracting the enzyme. It has been discovered that the locally isolated novel strain of A. terreus, SFH5, can efficiently produce a substantial amount of aspartic protease by utilizing agro-industrial waste. This makes it a viable candidate for large-scale optimized production of the enzyme to satisfy industrial requirements.

Synthesis of dynamic object control systems based on quantum calculation methods

Globally, food sourcing and processing focuses on achieving energy and resource efficiency. It is necessary to create and further improve effective models and algorithms for the synthesis of a control system, considering the features of complex technological processes, nonlinearity, and uncertainty of data. In the complex fermentation process, the variability of enzyme characteristics in the substance over time and the lack of measurement capabilities require the use of algorithms that provide high accuracy and speed. In this context, quantum algorithms demonstrate the ability to rapidly address problems that resist algorithmic solutions, processing large amounts of data in a short time In this article, an algorithm and model for searching the optimal values of a quantum controller were developed based on a quantum computing approach. Additionally, the characteristics of process variables and transient states are investigated using the Matlab software package. According to the model results, the fermentation temperature deviation from the nominal value and the process energy consumption were reduced by 1.2% and 2.3% respectively.

Aerobic Fermentation Drum Temperature Field Study for Cattle Mattress Regeneration

Aerobic fermentation is a key link in the regeneration system of cattle mattress material. In this paper, the three-dimensional structure of the aerobic fermentation drum was designed using SolidWorks software, and the discrete element model of the aerobic fermentation temperature field was established using Fluent software. The simulation analysis shows that the temperature inside the aerobic fermentation drum can be maintained stably between 60°C and 75°C by reasonably adjusting the feed rate, ventilation volume and drum speed, and the fermentation time of the regenerated bedding material can be adjusted from 8 to 22 hours, which can achieve continuous and stable feed and discharge production, indicating the feasibility and effectiveness of the aerobic fermentation process. When the feed rate is 2 m3/h, the ventilation rate is 180 m3/h and the drum speed is 0.3 r/min, a rated production rate of 48 m3/day can be met. The research has important reference value for aerobic fermentation process control and system design of cattle mattress material regeneration system.

Divergence in physicochemical and microstructural properties of set-type yogurt derived from bean proteins and animal milks: An inquiry into substitution viability

To clarify the comprehensive disparities in quality between bean- and milk-based set-type yogurts, this investigation undertook a thorough evaluation of the physicochemical and structural attributes of yogurts derived from three bean beverages with 12 g/100 mL (pea, fava bean, and chickpea) and three animal milk sources (Holstein cow, Jersey cow, and goat). The outcomes indicated that bean-based yogurts exhibited a reddish and had high adhesiveness and low tan δ, as well, the proportion of β-sheet declined and gels characterized by a more compact and dense protein structure with a high water-holding capacity (90–100%). Conversely, milk-based yogurts exhibited higher acidity and lower pH under identical fermentation temperature and post-ripening time conditions. Additionally, the proportion of β-sheet increased and gels featured a porous network structure with reduced water-holding capacity. Notably, fava bean yogurt demonstrated the highest adhesiveness (5.90 ± 0.03 N*s), hardness (4.76 ± 0.01 N), and apparent viscosity, and goat yogurt showcased notable cohesiveness (0.83 ± 0.02) and lowest viscosity and distinct wire drawing characteristics among the tested samples. Fava bean yogurt and Jersey cow yogurt garnered greater acceptability through sensory analysis. These findings underscore the contrasting attributes of bean- and milk-based yogurts, thereby contributing to the development of set-type yoghurts with different bean proteins.

Nutritional evaluation of probiotics enriched rabadi beverage (PERB) and molecular mapping of digestive enzyme with dietary fibre for exploring the therapeutic potential

Advent of the silent pandemic of obesity, which is associated with onset of various non-communicable and communicable disorders; led for the necessity to develop a functional food product with good nutritional profile to improve the overall health. Therefore, the current study was aimed to develop a probiotic enriched rabadi beverage. The beverage was prepared by using pearl millet, buttermilk and fortified with L. rhamnosus, Lactobacillus sp and S. faecalis. Subsequently, analysed for different parameters. Molecular mapping was also performed to show the inhibition profiling between cellulose and the human digestive enzymes. There was a significant difference for pH, acidity, viscosity, dry matter, and organic matter of PERB for autoclaved and non-autoclaved batches in all the used strains. However, a non-significant difference was observed in terms of different fermentation temperatures. The ash content varied significantly (0.32 ± 0.02%) in beverages fortified with S. faecalis fermented at 350 C, whereas moisture content had a non-significant effect on all the strains at different fermentation temperatures. Molecular mapping revealed the inhibition profiling in terms of binding affinity (kcal/mol) for various human digestive enzymes (Recombinant Acetylcholinesterase: −8.1, lysosomal acid-alpha-glucosidase: −6.6, and pancreatic alpha-amylase: −6.4) with cellulose. The study concluded that the PERB has a good amount of ADF, NDF, and hemicellulose content as well as indicated the significance of dietary fibre (cellulose) in regulating the digestibility through the interaction of gastrointestinal enzymes in order to explore the therapeutic potential of the PERB. Therefore, the developed PERB would serve as a potential source for better nutrition and overall health.

Variations in Ecuadorian Cocoa Fermentation and Drying at Two Locations: Implications for Quality and Sensory.

In Ecuador, various processes are applied during cocoa post-harvesting. This study, therefore, explored fermentation parameters across two locations with 2-7 independent runs, focusing on temperature, microbial counts, pH during fermentation and drying, and their impact on cocoa bean quality. Factors including fermentation devices (jute bags, plastic bags, and wooden boxes), pre-drying, turning during fermentation, fermentation duration, and drying temperature were investigated. Fermenting in plastic bags without pre-drying or turning and fermenting in jute bags for only 40 ± 2.0 h yielded low maximal fermentation temperatures Tmax (31.1 ± 0.4 °C and 37.6 ± 1.8 °C), leading to bitter, astringent, woody, and earthy cocoa liquor. Longer fermentation (63 ± 6 h) in wooden boxes with turning (Wt) and in jute bags with pre-drying and turning (Jpt) achieved the highest Tmax of 46.5 ± 2.0 °C, and a more acidic cocoa liquor, particularly in Wt (both locations) and Jpt (location E). Therefore, it is recommended to ferment for a minimum duration from day 1 to 4 (63 ± 6 h), whether using plastic bags (with mandatory pre-drying) or jute bags (with or without pre-drying or turning). Furthermore, this study underscores the risks associated with excessively high drying temperatures (up to 95.2 ± 13.7 °C) and specific dryer types, which can falsify cut-tests and introduce unwanted burnt-roasted off-flavors in the cocoa liquor.

Optimized Extraction and Fermentation of Antioxidant Polysaccharides from Polygonatum odoratum

Purpose: We wished to determine the optimal method for the extraction of polysaccharides with antioxidant activities from <i>Polygonatum odoratum</i>.Methods: Single-factor and orthogonal tests were applied to identify the best parameters for water extraction and fermentation. The solid-liquid ratio, temperature, and duration of water extraction were determined according to the total polysaccharide content. The fermentation temperature, agitation speed, inoculation amount, and fermentation time were investigated according to the optical density of Saccharomyces cerevisiae. The molecular weight distributions of water- and fermentation-extracted polysaccharides were determined by high performance gel permeation chromatography. The antioxidant activities of the polysaccharides were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS radical scavenging capacities, and ferric reducing antioxidant power (FRAP).Results: The optimum water extraction parameters were 80°C for 2.5 h with a 1:60 solid-liquid ratio. For fermentation, an 8% extraction volume was inoculated with <i>S. cerevisiae</i>. Optimal fermentation occurred at 28°C for 28 h, with an agitation speed of 180 r/min. The molecular weights of water- and fermentation-extracted polysaccharides were 2.067×10<sup>4</sup> and 9.475×10<sup>3</sup> Da, respectively. The DPPH, ABTS, and FRAP results demonstrated an obvious increase in antioxidant activity after fermentation.Conclusion: The fermentation extraction of <i>P. odoratum</i> may provide valuable materials for future cosmetic use.

Development of optimized functional clove fortified probiotic yoghurt.

We focused on assessing the antimicrobial effects of functional yoghurts supplemented with clove and probiotics. The formulation of aqueous clove extract (ACE) incorporated with probiotic yoghurt (Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactococcus lactis) was optimised in terms of aqueous clove extract concentrations (2.5-7.5% v/v), fermentation temperature (32-42°C), and total culture concentration (1.5-4.5% v/v). pH, titratable acidity, syneresis, water holding capacity, viscosity, springiness, color difference, lactic acid bacteria viability, and the antibacterial property of 17 runs were determined as responses using Box-Behnken design. The results indicate that elevated ACE concentration leads to a significant (p < 0.05) increase in titratable acidity, antibacterial effectiveness (against K. pneumoniae and P. aeruginosa), springiness, and color profile. Conversely, an elevated fermentation temperature significantly (p < 0.05) reduces pH and L. bulgaricus viability (log CFU/mL). Additionally, there is a significant (p < 0.05) decline in S. thermophilus and L. lactis viability (log CFU/mL) as well as springiness with an increased culture concentration. The optimal conditions identified are 7.5% (v/v) ACE concentration, a fermentation temperature of 36.6°C (37°C), and a total culture concentration of 4.5% (v/v), resulting in a 79% desirability score. The spectra of components were mainly obtained at wavelength of 3258cm-1, 1636cm-1 and 1075cm-1 in Fourier transform infrared (FTIR) spectroscopy of optimized functional yoghurt. Where, 3258cm-1 corresponds to the stretching vibration of O-H (hydroxyl) groups, 1636cm-1 corresponds to the C=O (carbonyl) stretching vibration, and 1075cm-1 corresponds to the C-O (ether or alcohol) stretching vibration.

Screening of Acetic Acid Bacteria Isolated from Various Sources for Use in Kombucha Production

The objective of this study was to isolate and identify strains of Acetobacter suitable for use in the development of a complex microbial culture for producing Kombucha and to examine the fermentation characteristics for selection of suitable strains. A medium supplemented with calcium carbonate was used for isolation of acetic acid bacteria from 22 various sources. Colonies observed in the clear zone resulting from decomposition of calcium carbonate by acid produced by microorganisms were collected. Identification of the collected strains was based on biological and morphological characteristics, and the results of base sequence analysis. A total of 37 strains were identified, including six species in the Acetobacter genus: Acetobacter pasteurianus, Acetobacter orientalis, Acetobacter cibinongensis, Acetobacter pomorum, Acetobacter ascendens, and Acetobacter malorum, as well as one species in the Gluconobacter genus, Gluconobacter oxydans. Among thirty-seven strains, seven strains of acetic acid bacteria with exceptional acid and alcohol tolerance were selected, and an evaluation of their fermentation characteristics according to fermentation temperature and period was performed. The results showed a titratable acidity of 1.68% for the Acetobacter pasteurianus SFT-18 strain, and an acetic acid bacteria count of 9.52 log CFU/mL at a fermentation temperature of 35 °C. The glucuronic acid and gluconate contents for the Gluconobacter oxydans SFT-27 strain were 10.32 mg/mL and 25.49 mg/mL, respectively.

Use of Non-Saccharomyces Yeast to Enhance the Acidity of Wines Produced in a Warm Climate Region: Effect on Wine Composition

One of the most notable effects of climate change, especially in warm regions, is the decrease in acidity (i.e., increase in pH) of wines and a reduction in their aromatic profile. To address this issue, must from a white grape variety with low acidity were inoculated with two non-Saccharomyces yeasts (Lachancea thermotolerans and Torulaspora delbrueckii) to enhance the acidity of the resulting wines. Basic oenological variables and major volatile compounds and polyols of the wines were analyzed, and the results were compared with those obtained through a Saccharomyces cerevisiae strain. Through multiple regression analysis, we found relations between the production of lactic acid to compounds involved in yeast metabolism and redox balance, including glycerol, acetic acid, isobutanol, isoamyl alcohols, and 2-phenylethanol. By means of principal component analysis, we obtained three components that explain more than 89% of the observed variability. The first component differentiates wines produced by L. thermotolerans; the second differentiates wines obtained by S. cerevisiae from those obtained by T. delbrueckii; and the third component is related to the temperature of fermentation. Organoleptic wines produced with S. cerevisiae were the best valuated, but taste was a highlight of the wines produced with L. thermotolerans due to possessing the best acidity.

FERMENTATION OF KVASS WORT BY INDUSTRIAL STRAINS OF MICROORGANISMS

We investigated the fermentation of kvass wort using yeast from the brewing industry and ready-made leaven of lactic acid bacteria. The raw materials for making kvass are kvass wort concentrate, sugar syrup, and rosehip extract. The content of dry substances in the initial wort is 3.2 wt. %, and pH = 5.8. Safale HA-18 dry yeast (optimal fermentation temperature is 25–35°C) and complexes of lactic acid bacteria in the form of starters "Kefir", "Yogurt", "Symbiotic", "Bifivit" of different microbiological compositions are used for kvass wort fermentation. We investigated the dynamics of the content of dry substances and the acidity under different fermentation conditions of kvass wort. The normalized value of the content of dry substances in kvass wort was obtained when using the "Bifivit" lactic acid bacteria starter at a temperature of 30°C, and the ratio of yeast, lactic acid bacteria in the starter is 50 % : 50 %. It is explained by the insufficient temperature necessary for the full reproduction of yeast and the impurity part of lactic acid bacteria. With an increase in the fermentation temperature of kvass to 35°C and a simultaneous increase in the proportion of yeast in the suspension, an increase in fermentation activity in all studied samples was observed. According to research, the optimal amount of yeast and lactic acid bacteria in the suspension is 4 wt. %. The optimal ratio of yeast in the mixture is 80 wt. % and lactic acid bacteria is 20 wt. %. According to the conditions of the experiment, norms of the content of dry substances (2.4 wt. %) and increased acidity (by 1.2 ml 0.1 N NaOH/100 ml) were achieved by samples No. 1 and No. 4 during 14–16 hours of fermentation. We suggested blending the prepared kvass with rosehip extract to give the drink additional functional and preventive properties. The blending of kvass with sugar syrup and rosehip extract was carried out to the content of dry substances 4.2 wt. % and a titrated acidity of 3 ml 0.1 N NaOH/100 ml. A comparative tasting evaluation of kvass with rosehip extract is given. Blending has an excellent effect on organoleptic indicators and gives the drink additional functional and preventive properties. The perspective of using industrial strains of microorganisms for the fermentation of kvass wort for small craft breweries is indicated

PROCESSING OPTIMIZATION OF CRAFT CHEESE CAMEMBERT TYPE

The article substantiates the technology of craft cheese Camembert type with the use of goat milk and dried plant products for restaurants implementation. Differences in the biological value and technological properties of goat and cow milk were analyzed. It is shown that goat milk contains more protein, fat, lactose, potassium, calcium, magnesium and iodine in comparison to cow milk. The density of goat milk is about 1.033 g∕cm3, while for cow milk this indicator varies within 1.024 and 1.037 g∕cm3. Goat milk compared to cow milk contains more retinol, thiamine, ascorbic acid and less such an allergens as αs1-casein and α-lactoalbumin, that proofs an increased biological value of goat milk. Using the methods of experimental and statistical planning, a quadratic model was obtained that adequately describes the dependence of the cheese hardness parameter on the the milk fermentation temperature and the dosage of goat milk in the recipe of Camembert type cheese. As a result of the minimization of the cheese hardness parameter according to the obtained model, it was determined that the of goat milk should be added in the recipe of craft cheese Camembert type in an amount of 35.6% of cow milk content, and the fermentation of milk should be carried out at a temperature of 36°C. These parameters allow to obtain cheese with the hardness of 13.2%. A technological scheme for the production of craft cheese Camembert type was developed, that attaches mixing of goat milk and cow milk, fermentation of milk at a temperature of 36°C, as well as the addition of dried plant products, such as thyme, rosemary and tomatoes at the stage of a clot processing . Based on the results of the evaluation of the organoleptic quality indicators of the cheese, it was found that it has the correct shape, rich and balanced taste, as well as a soft and delicate consistency, which allows to recommend it for implementation into restaurants production.

Fibrinolytic Protease Production: Impact of Initial pH and Temperature in Solid-State Fermentation by Rhizopus microsporus var. oligosporus FNCC 6010

Background: Fibrinolytic enzyme is one of the cardiovascular disease therapies. Rhizopus microsporus var. oligosporus is microorganism that has been evaluated to produce fibrinolytic protease by fermentation. This study conducted fermentation of helianthi annui semen (sunflower seed) by Rhizopus microsporus var. oligosporus to produce fibrinolytic enzyme. Objective: This study aims to determine the effect of Initial pH and incubation temperature and its optimization in the production of fibrinolytic protease by Rhizopus microsporus var. oligosporus FNCC 6010 in solid-state fermentation on helianthi annui semen (sunflower seed) substrate. Optimum condition was determined by maximum protease and fibrinolytic activity. Method: A crude enzyme of protease fibrinolytic was obtained from the supernatant extract of fermented sunflower seed. Protease activity was measured by the skimmed milk agar (SMA) plate method, and fibrinolytic activity was determined by the fibrin agar plate method. Result: It was found that the starting pH affects both the proteolytic and fibrinolytic activity of enzymes that are produced in fermentation. The starting pH of 5.0 showed higher fibrinolytic and proteolytic activity values compared to the starting pH of 7.0. The incubation temperature 33±1 °C had the higher activity compared to 28±1 °C or 37±1 °C. Conclusion: Initial pH and incubation temperature affect the proteolytic and fibrinolytic activity of crude enzyme extracted from fermented sunflower seed by Rhizopus microsporus var. oligosporus. The optimum condition for producing fibrinolytic protease in the state fermentation method was an initial pH of 5.0 and an incubation temperature of 33±1°C.

Promoting a circular economy by developing new gastronomic products from brassica non‐edible leaves

SummaryThis study aims to apply circular economy principles by reintroducing discarded Brassica leaves into the value chain as innovative products. Non‐edible leaves of three Brassica varieties were used to develop kombucha, a fermented beverage with health benefits. The fermentation time (9 days), temperature (25 °C), starter culture, and container shape (2 L round‐shape glass jar) influenced the beverage's physicochemical properties, including pH, vitamin content, polyphenols, and sugar levels. Different Brassica varieties showed various effects on antioxidant capacity and polyphenol content during fermentation, with potential implications for microbial engagement. Sensory analysis revealed differences in appearance, colour, aroma, and taste between black tea and Brassica samples, which are due to glucosinolates and volatile compounds, thus providing opportunities for improving consumer acceptability through flavour masking. Overall, this work showcases the potential of using non‐edible Brassica by‐products and highlights the potential of fermented beverages like kombucha to address food waste and promote value addition from otherwise discarded plant parts.

The fermentation optimization for alkaline protease production by Bacillus subtilis BS-QR-052.

Proteases exhibit a wide range of applications, and among them, alkaline proteases have become a prominent area of research due to their stability in highly alkaline environments. To optimize the production yield and activity of alkaline proteases, researchers are continuously exploring different fermentation conditions and culture medium components. In this paper, the fermentation conditions of the alkaline protease (EC 3.4.21.14) production by Bacillus subtilis BS-QR-052 were optimized, and the effect of different nutrition and fermentation conditions was investigated. Based on the single-variable experiments, the Plackett-Burman design was used to explore the significant factors, and then the optimized fermentation conditions, as well as the interaction between these factors, were evaluated by response surface methodology through the Box-Behnken design. The results showed that 1.03% corn syrup powder, 0.05% MgSO4, 8.02% inoculation volume, 1:1.22 vvm airflow rate, as well as 0.5% corn starch, 0.05% MnSO4, 180 rpm agitation speed, 36°C fermentation temperature, 8.0 initial pH and 96 h incubation time were predicted to be the optimal fermentation conditions. The alkaline protease enzyme activity was estimated to be approximately 1787.91 U/mL, whereas subsequent experimental validation confirmed it reached 1780.03 U/mL, while that of 500 L scale-up fermentation reached 1798.33 U/mL. This study optimized the fermentation conditions for alkaline protease production by B. subtilis through systematic experimental design and data analysis, and the activity of the alkaline protease increased to 300.72% of its original level. The established model for predicting alkaline protease activity was validated, achieving significantly higher levels of enzymatic activity. The findings provide valuable references for further enhancing the yield and activity of alkaline protease, thereby holding substantial practical significance and economic benefits for industrial applications.

Antarctic Soil Yeasts with Fermentative Capacity and Potential for the Wine Industry.

Low fermentation temperatures are usually employed to obtain high-quality wines. This is especially interesting for white wine production since it prevents the loss of volatile compounds and a browning appearance; however, available fermentative yeasts do not usually tolerate low temperatures. Therefore, an interesting place to find new yeasts with cryotolerance is the Antarctic continent. From soil samples collected in Antarctica, 125 yeasts were isolated, of which 25 exhibited fermentative activity at 10 °C. After a fingerprinting assay, we classified the candidates into nine isotypes and sequenced internal transcribed spacer regions for their identification. These yeasts were identified as part of the Mrakia genus. Sugar and alcohol tolerance tests showed that some of these Antarctic soil yeasts were able to grow up to 9% alcohol, and 25% sugar was reached; however, they exhibited longer latency periods compared to the control Saccharomyces cerevisiae. The optimal growing temperature for the isolated Antarctic yeasts was between 10 °C and 15 °C. A comprehensive analysis of the results obtained showed that the isolates 10M3-1, 4M3-6, and 4B1-35 could be good candidates for fermentation purposes due to their alcohol, sugar tolerance, and growth features. Our results prove that it is possible to isolate fermentative yeasts from Antarctic soil with promising characteristics for their potential use in the wine production industry.

Structural Characterization and Properties of Modified Soybean Meal Protein via Solid-State Fermentation by Bacillus subtilis.

Soybean meal (SBM) is a high-quality vegetable protein, whose application is greatly limited due to its high molecular weight and anti-nutritional properties. The aim of this study was to modify the protein of soybean meal via solid-state fermentation of Bacillus subtilis. The fermentation conditions were optimized as, finally, the best process parameters were obtained, namely fermentation temperature of 37 °C, inoculum amount of 12%, time of 47 h, and material-liquid ratio of 1:0.58, which improved the content of acid-soluble protein. To explore the utilization of modified SBM as a food ingredient, the protein structure and properties were investigated. Compared to SBM, the protein secondary structure of fermented soybean meal (FSBM) from the optimal process decreased by 8.3% for α-helix content, increased by 3.08% for β-sheet, increased by 2.71% for β-turn, and increased by 2.51% for random coil. SDS-PAGE patterns showed that its 25-250 KDa bands appeared to be significantly attenuated, with multiple newborn peptide bands smaller than 25 KDa. The analysis of particle size and zeta potential showed that fermentation reduced the average particle size and increased the absolute value of zeta potential. It was visualized by SEM and CLSM maps that the macromolecular proteins in FSBM were broken down into fragmented pieces with a folded and porous surface structure. Fermentation increased the solubility, decreased the hydrophobicity, increased the free sulfhydryl content, decreased the antigenicity, improved the protein properties of SBM, and promoted further processing and production of FSBM as a food ingredient.

Investigation the nutritional properties of Auricularia auricula pulp fermented with Lactobacillus strains and their effects on gut microbiota.

Auricularia auricula is rich in bioactive components, and microbial fermentation can further dramatically increase its content and bioavailability. However, there are few studies on the relationship between fermented A. auricula pulp (FAAP) and gut microbiota. In this study, standard strains Lactobacillus plantarum 21801 and 21805 purchased from the China Center of Industrial Culture Collection were used to ferment A. auricula pulp at a ratio of 2:1, with an inoculum of 5%, a fermentation temperature of 31 °C, and a fermentation time of 22 h. The nutritional properties, aroma, and color of FAAP and their effects on the body characteristics of mice and the structure and abundance of gut microbiota are discussed. The results showed that, compared with A. auricula pulp, FAAP significantly increased the nutritional properties while maintaining favorable sensory quality and flavor profiles. Among them, the content of total polyphenols and total flavonoids reached 22.04 μg mL-1 and 20.56 μg mL-1 respectively, and the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid free-radical scavenging rate increased to 73.21%. The consumption of FAAP had no negative effects on weight or liver and kidney function in mice and dramatically enhanced the antioxidant capacity in the liver and serum. The production of short-chain fatty acids in the gut was promoted, the relative abundance of beneficial bacteria (Lactobacillus, Bifidobacterium, norank_f__Muribaculaceae and unclassified_f__Lachnospiraceae) increased, and the growth of some pathogenic bacteria (Helicobacter, Mucispirillum, and Alloprevotella) was inhibited. These findings demonstrate that FAAP is rich in nutrients and has unique functional properties that promote host health and regulate the gut microbiota. © 2023 Society of Chemical Industry.