Listeria monocytogenes is a food-borne pathogenic bacterium, which can cause serious food public health security problems.The antimicrobial peptide PNMGL2 from Lactiplantibacillus plantarum has obvious inhibition on the foodborne pathogenic bacteria, but its antibacterial mechanism is unclear.Time-kill assays showed that PNMGL2 could effectively inhibit the growth of L.monocytogenes.The propidium iodide (PI) uptake and release of lactate dehydrogenase (LDH) experiments suggested that PNMGL2 could damage the integrity of cell membrane of L.monocytogenes.Furthermore, observation by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and confocal laser-scanning microscopy (CLSM) indicated that PNMGL2 induced visual cell damage, promoted the formation of pores, destroyed the integrity of cell membrane, increased the permeability of membrane, and triggered leakage of intracellular substances (phosphorus, potassium, ATP, proteins, and nucleic acids).In addition, PNMGL2 could inhibit biofilm formation of L.monocytogenes and hemolytic activity of exotoxins.This study preliminarily elucidated the antibacterial mechanism of PNMGL2 against L.monocytogenes, providing a theoretical basis for the development and utilization of PNMGL2 as a new food antimicrobial agent.

This study aimed to investigate the structure-activity relationships of the rearranged peptides designed based on ACE inhibitory peptides from Urechis unicinctus.Five ACE inhibitory peptides derived from U. unicinctus found by the research group were rearranged in the amino acid sequences and 20 recombinant peptides were designed.Among them, five rearranged peptides that best conform to empirical rules were selected.The activity effects and structure-activity relationships were evaluated through ACE inhibition activity testing, Lineweaver Burk double reciprocal enzyme inhibition kinetics experiments, and computer molecular simulation docking.Results showed that the IC₅₀ values of the rearranged peptides F2-1, F3-1, F4-1, F5-1, and F7-1 on ACE inhibitory activity were (10.15±0.36), (6.38±0.22), (35.05±0.38), (44.14±0.71), and (25.73±0.24) μmol/L, respectively.Compared with the IC₅₀ of the natural peptides obtained from U. unicinctus F2[(75.47±0.61) μmol/L], F3[(110.45±0.37) μmol/L], F4[(46.32±0.42 μmol/L], F5[(56.35±0.53) μmol/L], and F7[(60.23±0.48) μmol/L], the rearranged peptides showed a significant decrease, indicating a noteworthy increase on ACE inhibitory activity.The Lineweaver Burk plot indicated that all five rearranged peptides exhibit ACE competitive inhibition patterns.The molecular docking simulation results showed that they could interact with ACE by forming multiple hydrogen and hydrophobic bonds with active pockets or sites outside the pockets.Compared with F3, F3-1 transformed from a non-competitive inhibitor to a competitive inhibitor, with an increase in activity of 16.31 times.From this, it could be seen that the amino acid sequence of ACE inhibitory peptides and the hydrophobicity of the N-terminal and C-terminal of the peptide chains had a significant impact on their ACE inhibitory activity.It is an effective method for natural ACE inhibitory peptides to perform sequence regulation or modification optimization and obtain efficient ACE inhibitory active peptides.

L-Leucine is an important branched-chain amino acid with significant value in various fields such as pharmaceuticals, food, feed, and cosmetics.Currently, the industrial production of L-leucine using strains faces challenges including low conversion rates, high levels of by-products, and substantial decreases in yield after crystallization.To obtain a superior strain for L-leucine production, this study conducted systematic metabolic engineering on the L-leucine-producing strain Corynebacterium glutamicum CP.Firstly, competitive pathways were knocked out, and exogenous phosphoenolpyruvate carboxykinase (encoded by fxpk) was introduced to enhance the supply of precursors (pyruvate and acetyl-CoA).Secondly, the main metabolic flux (including the pathways for L-leucine and branched-chain amino acids) was reinforced to increase L-leucine production.Subsequently, intracellular NADPH supply was enhanced.Finally, the L-leucine intracellular transport protein BrnQ was knocked out.The engineered strain CP06-1 obtained could efficiently produce L-leucine, with a yield of 65.3 g/L after 50 hours of fermentation in a 5 L bioreactor, and a yield of 0.251 g/g glucose.Moreover, to address the issue of foam generation affecting nutrient absorption and oxygen solubility after L-leucine crystallization, semi-continuous fermentation was adopted.Before L-leucine crystallization, the effluent was released and supplemented, extending the acid production peak of the strain.Ultimately, in the 50-hour fermentation in a 5 L bioreactor, a total of 228.8 g of L-leucine was produced, with a yield of 0.279 g/g glucose, representing an 11.2% improvement over batch feeding.This study provides valuable guidance for the modification and utilization of L-leucine-producing strains.

Steviol glycosides are a natural, non-nutritive, high-intensity sweetener with functional properties, known as the world’s third sugar source.Stevioside is the main sweetening component of Steviol glycosides, with its molecular structure containing three glycosidic bonds available for hydrolysis.The specific hydrolysis of the glycosidic bond in stevioside can yield functional glycosides with varying sweetness and properties.This article first discovered that lipase A from Aspergillus niger can specifically hydrolyze stevioside to prepare rubusoside.This study investigated the effects of factors such as temperature, pH, substrate concentration, enzyme dosage, metal ions, etc., on the enzymatic reaction with a single-factor optimization method, and conducted a preliminary analysis of the reaction pathway.Results indicated that lipase A exhibited high specificity towards stevioside, with the main hydrolysis product being rubusoside.Under the optimal conditions of 55 ℃, pH 4.5, and an enzyme dosage of 1 200 U/g, the conversion rate of stevioside could reach 99% after a 9-hour reaction, with a rubusoside yield of 90%.This study expanded the preparation methods of rubusoside, which is of significant importance for the in-depth application of stevia glycosides.

Based on the theoretical basis of bioinformatics, this paper used the computer to simulate the enzymatic digestion of Tibetan sheep hemoglobin, using online activity scoring, activity prediction, and molecular docking techniques to screen their antioxidant peptides and verify their antioxidant properties by DPPH free radical and ABTS cationic free radical scavenging rate experiments.The amino acid sequences of Tibetan sheep hemoglobin were screened using the UniProt database to evaluate its potential bioactivities, ExPASy Peptide Cutter online tool was applied to enzymatically digest the screened peptide chains, Peptide Ranker was applied to score the bioactivity prediction, and the online tools Innovagen, ToxinPred, iBitter-SCM, A11erTOP, and AdmetSAR for solubility, toxicity, bitterness, sensitization and ADMET, molecular docking using Keap1 receptor for activity prediction, and finally validation of the screened antioxidant peptides of Tibetan sheep hemoglobin using DPPH free radical and ABTS cationic free radical scavenging rate assay.Results showed that five Tibetan sheep hemoglobin chains contained 20 amino acids, and a total of 258 kinds of peptide (485 peptides) were obtained by enzymatic digestion, and 110 kinds of peptide (194 peptides) with ratings greater than 0.5 were screened out by the bioactivity scoring system, and 18 kinds of peptide with good solubility, non-toxicity, non-bitterness, and non-allergenicity were obtained through the prediction of their activities, and the molecular docking was carried out for the 10 peptides that had a better intestinal absorption, and the top three peptides with molecular docking scores, KRM, FPL, and FL, were subjected to in vitro antioxidant activity assay, and the results showed that the free radical scavenging ability of FPL and KRM exceeded the positive control, with KRM exceeding the positive control for DPPH radicals and ABTS cationic radicals with IC₅₀ of (0.125 0±0.012 3) and (0.339 1±0.031 4) mg/mL, respectively, and FPL exceeding the positive control for DPPH radicals and ABTS cationic radicals with IC₅₀ of (0.256 5±0.014 1) and (0.374 6±0.047 1) mg/mL, respectively. and the scavenging ability of FL for DPPH radicals and ABTS cation radicals reached 88.90% and 94.40% of that of the positive control, with IC₅₀ of (1.106 1±0.279) and (1.601±0.031 4) mg/mL, respectively, both of which showed strong antioxidant activity. This method could screen antioxidant peptides quickly and economically compared with the traditional enzyme digestion experiments, and provide a research basis for the high-value utilization and development of Tibetan sheep blood resources.

To study the mechanism of action of Alhagi-honey acid polysaccharide in improving ulcerative colitis (UC) model mice induced by dextran sulfate sodium sulfate (DSS), its effect on the intestinal microbiota of mice was analyzed.Forty SPF male C57BL/6 mice were randomly divided into control group, model group, mesalazine group (100 mg/kg), and low- and high-dose groups (100, 400 mg/kg).Mice were induced to the UC model by drinking 3% (mass fraction) DSS solution freely for 7 days, while mice in the mesalazine group and the low and high-dose groups of Alhagi-honey acid polysaccharide were gavaged with the corresponding drug solution, and the control group and the model group were given the same volume of deionized water.The disease activity index (DAI) score, body weight, colon length, and histopathological changes of the colon were observed, the secretion of inflammatory factors in the serum of mice was detected, and the 16S rRNA sequencing of mouse fecal samples was performed by Illumina high-throughput sequencing technology.Compared with the model group, the DAI score, body weight, and colon length of mice in the high-dose group and mesalazine group were significantly reduced, the pathological damage of the colon was significantly improved (P<0.05), and the changes in intestinal microbiota diversity of UC mice were effectively regulated.At the phylum level, the relative abundance of Bacteroidetes increased, while the relative abundance of Proteobacteria decreased.At the genus level, the abundance of beneficial bacteria in Akkermansia increased significantly, while the abundance of pathogenic bacteria in Escherichia decreased.Alhagi-honey acid polysaccharide can improve the diversity of intestinal flora, increase beneficial bacteria and reduce harmful bacteria, reduce the secretion of inflammatory factors, and alleviate the symptoms of UC.

In this study, Limosilactobacillus fermentun WHH2483 isolated from 168 lactic acid bacterial strains originating from traditional fermented foods, showed potential for caries prevention.This strain demonstrated the ability to inhibit the growth and biofilm formation of Streptococcus mutans ATCC25175, with an inhibition zone diameter of (21.20±1.42) mm and a biofilm inhibition rate of (95.05±3.25)%.WHH2483 also showed good oral colonization potential, with an auto-aggregation rate of (39.19±1.65)% and a co-aggregation rate of (77.08±1.08)%, while exhibiting low adhesion to hydroxyapatite [adhesion rate of (20.72±1.20)%].A dental caries model in SD rats was established to validate the caries-preventive function of the strain.WHH2483 can significantly inhibit the proliferation of Streptococcus mutans in the oral cavity of rats, increase the loss of enamel surface and volume, reduce the levels of caries, maintain the integrity of tooth structure, and reduce the occurrence and development of caries.This study provides foundational support for the development and application of L. fermentum WHH2483 as a probiotic for preventing dental caries.

High concentrations of anthocyanins in fermented fruit wine affect the accuracy of reducing sugar detection by DNS colorimetry.Particularly in the late stage of fermentation, the fruit wine is dark in color and has a low sugar content, which increases the difficulty of detection.In this study, three methods, decolorization with polyvinylpyrrolidone (PVP), blank control, and sample dilution, were used to reduce the interference of anthocyanins on DNS colorimetry.It was found that PVP-K30 has the function of adsorbing anthocyanins, but it could not completely eliminate color interference.For samples with high anthocyanin content, the detection result obtained by the blank control method was closer to the real value.The specific approach was to select 200 μL of the sample to be tested, add 150 μL of DNS reagent, and use it without boiling treatment as a blank control.From the perspective of eliminating pigment interference, the greater the dilution factor, the smaller the anthocyanin interference.In the detection of fruit wine, the confirmation of the dilution factor also needed to consider the initial reducing sugar concentration of the sample.The study found that there is an optimal dilution factor range.For samples with 100-200 g/L reducing sugar, a 200-fold dilution was the best.For samples with 50-100 g/L reducing sugar, a dilution within 100 times was better.For samples with 10-50 g/L reducing sugar, a dilution within 50 times had better accuracy.It indicated that from the perspective of reducing sugar when the sugar content of the diluted sample was 0.2-1 g/L, the detection effect was better.Therefore, for the detection of reducing sugar in dark fruit wine, it was recommended to combine blank control and sample dilution operations to improve accuracy.This study further took blueberry wine fermented by Saccharomyces cerevisiae CECA as an example and used the improved DNS method to monitor the reducing sugar content in four fermentation periods.The expression levels of five genes related to reducing sugar metabolism were analyzed.In the early stage, the expression levels of GLK1 and HXK1 were relatively high.In the middle and late stages, HXK2, PFK1, and PFK2 were all highly expressed.In the late stage, the expression levels of all five genes were relatively low.The reducing sugar content was positively correlated with the expression levels of GLK1 and HXK1 genes.This study provides a methodological reference for the rapid and accurate monitoring of reducing sugar in the fermentation of dark fruit wine and explores the association between the expression of reducing sugar-related genes and sugar metabolism in blueberry wine fermentation, which has theoretical research value for improving product quality and monitoring approaches.

To investigate the hydrogen production performance of Clostridium spp. as an efficient hydrogen-producing fermentation strain, a strain named WZ-1, identified as Clostridium guangxiense, was isolated from the pit mud of Nongxiangxing Baijiu due to its hydrogen-producing ability.Under anaerobic conditions at 35 ℃, strain WZ-1 demonstrated the capacity to produce high levels of hydrogen (58.99%) and butyric acid (1 960 mg/L) through fermentation on a medium with glucose as the substrate.To comprehensively analyze its functional properties, the genome of strain WZ-1 was sequenced and annotated.Genomic analysis revealed that the total length of the WZ-1 genome was 4 406 933 bp with a guanine cytosine content of 31.95%, including 4 172 coding sequences, 3 rRNA genes, and 52 tRNA genes.Analysis of KEGG metabolic pathways of the strain revealed hydrogen production during pyruvate decarboxylation, hydrogen production by NADH+H⁺ redox balance regulation, hydrogen production by carbon monoxide, hydrogen production by nitrogen fixation, and its butyric acid-producing pathway in WZ-1.The results of this study analyzed the hydrogen and butyric acid production characteristics of WZ-1 at the genomic level and indicated that WZ-1 holds promising application prospects in the fields of hydrogen production, butyric acid production, and promoting circular economy initiatives.Furthermore, these findings provide valuable insights for the development of clean energy production technologies.

Based on the traditional fermentation process of Daqu, the quality differences in high-temperature Daqu made by the traditional and shelf stacking methods were compared, to investigate the high-temperature Daqu fermentation feasibility by shelf stacking methods.Results demonstrated that the reducing sugar contents and acidity of yellow Daqu were higher than that of white Daqu made by different stacking methods.The saccharifying power of high-temperature Daqu made by shelf stacking method B (SSMB) was close to that of high-temperature Daqu made by the traditional stacking method (TSM).The volatile contents of high-temperature Daqu made by SSMB were the highest, indicating that the SSMB was more favorable for volatiles produced via microbial biosynthesis.In addition, the alcohols, acids, pyrazines, and aldehydes were dominant volatiles in high-temperature Daqu made by different stacking methods.The microbial community structures of high-temperature Daqu made by different stacking methods were similar with each other, but some differences were also observed in microbial relative abundance.Virgibacillus, Bacillus, Kroppenstedtia, and Thermoactinomyces were dominant bacteria and Thermomyces and Thermoascus were dominant fungi.The different stacking methods had significant influences on the bacterial community but had little influence on the fungal community.The press existed between Daqu stacked using the traditional method caused weak air flow between Daqu.The supporting effect of the shelf to Daqu increased the space between Daqu, thereby further increasing the loose degree of Daqu stack and improving the dissolved oxygen contents during Daqu fermentation.It resulted in the microbial community differences between Daqu samples.The correlation analysis indicated that saccharifying power, liquefying power, and fermentation power were positively correlated with Bacillus, Thermoascus, and Aspergillus, due to their capability of hydrolase biothesis.The differences in microbial relative abundances and biosynergies between microbes in Daqu samples resulted in differences in enzymatic activities and volatiles.Overall, the SSMB is suitable for investigating mechanized fermentation of high-temperature Daqu.

Aming to analyze the bacterial community diversity of fermented products with characteristics belonging to the plateau region, lactic acid bacteria were isolated and identified from highland barley wine brewing by-products, including barley lees, yellow water, and naturally fermented camel milk, by traditional isolation and culture technology in this paper.The bacterial diversity was analyzed based on metagenomic 16S rRNA gene second-generation sequencing technology.Results showed that the bacteria in these samples were composed of 38 phyla, 779 genera, and 914 species, among which, Firmicutes (85.82%), Proteobacteria (3.87%), Bacteroidetes (2.5%), Actinobacteria (1.18%) were the dominant phyla in the sample, and Pediococcus (36.12%), Enterococcus (31.98%), Lactococcus (15.49%), and others were the genus with higher abundance.Among them, the bacterial diversity and abundance of highland barley distilling lees were the largest, while those of naturally fermented camel milk in winter were the opposite.This study provides a new reference for the analysis of microbial diversity in highland barley wine brewing by-products, as well as the difference in bacterial community between lees and fermented milk.

To better manage the quality of Daqu and increase the yield of the original liquor, it is crucial to obtain a deeper understanding of the physicochemical indicators and microbial community succession during the storage period of medium- and high- temperature Daqu.Four samples from various storage times were taken from the Luzhou-flavor koji workshop in Northwest China for this investigation.MiSep high-throughput sequencing was utilized to study the diversity of the microbial community during Daqu storage, based on the assessment of their physicochemical parameters.According to the findings, Daqu’s moisture content ranged from 11% to 12% during storage (0-3 months), and after 90 days, its acidity reached 0.75 mmol/10 g.As compared to before they left the room, there was a 66.7% rise in the koji sample.The diversity and richness of microorganisms in Daqu dropped initially and then increased, the most common species were Thermoactinomyces (55.33%), Saccharopolyspora (21.70%), and Thermomyces (59.33%).With storage time, the relative amounts of Weissella and Lactobacillus were generally increasing.Correlation analysis revealed a positive correlation between Lactobacillus, Saccharopolyspora, Weisella, Aspergillus, and Wickerhamomyces with saccharification power.Additionally, Thermomyces showed a positive correlation with liquefaction power, fermentation power, and esterification power.The structure of the microbial population is seen to be continuously modified, balanced, and even stable during the Daqu storage process.It is also related to physical and chemical indexes, which have a direct impact on the yield and quality of liquor.As a result, storing Daqu at medium and high temperatures is a crucial step in the making of liquor.

As the ageing time of dry red wine increases, the body color of the wine becomes very yellow, which affects the color stability of the wine.In this study, organic acids such as tartaric acid, malic acid and lactic acid were added to the grape mash for fermentation at different ratios and concentrations.The basic physicochemical indicators (alcohol, reducing sugar, total acid, volatile acid, pH), color parameters (L^*, a^*, b^*, C^*_ab, H_ab) and the content of six organic acids (oxalic acid, tartaric acid, malic acid, lactic acid, citric acid, succinic acid) of wine were analyzed by Foss automatic analyzer and high performance liquid chromatography at the end of alcohol fermentation and six months of aging.The results showed that the color of wine added with compound acids in grape mash has a brighter color.Among them, wine with added tartaric acid of 2 g/L, malic acid of 1 g/L, and lactic acid of 1 g/L has a higher red/green degree a^* and a significantly lower blue/yellow degree b^*.In addition, the effect of composite acids on color is the result of the synergistic production of multiple components.This process will provide an effective reference for improving the color stability of dry red wine in Xinjiang production areas.

Shrimp paste, one of the traditional fermented aquatic products in China, has a unique flavor that is influenced by fermentation environment and microorganisms.In this study, the fermentation quality of shrimp paste was evaluated by determining the endogenous environment (pH, amino acid nitrogen, volatile base nitrogen, malondialdehyde and bioamine).Moreover, the succession of prokaryotic microbial communities during fermentation was investigated by using high-throughput sequencing technology.The results showed that pH, amino acid nitrogen, volatile basic nitrogen and malondialdehyde content were in range of 7.24-7.84, 0.06-1.21 g/100 g, 26.52-90.33 mg/100 g and 0.11-1.62 mg/kg, respectively.Tryptamine was the main biogenic amine in shrimp paste, accounting for about 60% of the total biogenic amine content.It was found that the diversity and richness of prokaryotic microbial community in shrimp paste gradually decreased with the extension of fermentation time.Halanaerobium, Tetragenococcus and Lactobacillus were the dominant prokaryotic microbial genera at the late stage of shrimp paste fermentation.After 35 days of fermentation, the sum of their relative abundances reached 86.78%.Redundancy analysis showed that the succession of prokaryotic microbial community in shrimp paste fermentation was driven by multiple endogenous environments.The results revealed the dynamic changes in the interaction relationship between the prokaryotic microbial community and the endogenous environment during shrimp paste fermentation, which provided data reference for precise artificial regulation.

The Chinese characteristic jujube honey was applied to develop functional goat milk yogurt, and the changes in product quality during refrigeration were evaluated.Jujube honey with different proportions of 4%, 8%, and 12% was added after the fermentation of goat milk, and the effects of the addition of jujube honey on the sensory quality, titratable acidity, pH, lactic acid bacteria amount, texture properties, water holding capacity, and antioxidant activity of goat milk yogurt during 28 days of refrigeration were investigated.Results showed that jujube honey could significantly improve and maintain the sensory quality of goat milk yogurt during shelf-life, and effectively reduce its acidification rate.The number of viable lactic acid bacteria decreased with the increase of jujube honey addition and continued to decline during refrigeration, while it was still significantly higher than the national standard limit at the end of refrigeration.The texture properties of goat milk yogurt added jujube honey reached maximum values after 14 days of refrigeration, with hardness, consistency, cohesiveness, and viscosity increasing by 19.50%-34.96%, 16.72%-23.16%, 26.86%-33.06% and 8.50%-12.01%, respectively, and their water-holding capacities were also maintained better than that of control yogurt.In addition, jujube honey endowed the product with stronger antioxidant activities, which increased further during refrigeration.Therefore, the jujube honey addition effectively enhances the quality and functional value of goat milk yogurt during its shelf-life, and it is an excellent choice for developing new functional goat milk products.

This study aimed to compare the microbial composition differences and predict gene functions between traditional grain fermentation drinks of Magzim and Boza.A metagenomics approach was used to analyze the microbial community composition in these two drinks.The PICRUSt2 and FUNGuild software were used to predict gene function.Results showed that the dominant genera of microbial communities in Magzim were Lactobacillus (25.46%), Leuconostoc (12.88%), Streptococcus (9.60%), Alternaria (45.15%), Cladosporium (9.21%), Candida (8.99%) and Gibberella (2.3%), while microbial communities in Boza were dominated by Lactobacillus (86.67%), Pediococcus (1.10%), Acinetobacter (1.07%), Leuconostoc (1.06%), Streptococcus (1.01%), Pichia (18.11%), Rhizopus (16.41%), Alternaria (10.9%), Issatchenkia (7.95%), Nigrospora (6.80%), Gibberella (6.69%), and Wickerhamomyces (4.37%).Functional prediction analysis revealed that genes related to bacterial growth and reproductive metabolism, particularly carbohydrate and amino acid metabolism, played a key role in microbes.In conclusion, microbial community composition was significantly different in different types of ethnic traditional grain fermented beverages in the Yili region, but bacteria may play a leading role in fermentation.This study provides a reference for the mining and utilization of beneficial microbial resources in traditional fermented foods.

Pomegranate peel was used as a test material to study its antibacterial activity against the food-borne putrefactive bacterium Bacillus cereus and its effect on cell membrane permeability and integrity.This study provides a theoretical basis for the development of safe plant-derived preservatives and deep utilisation of pomegranate peel.The antibacterial activity showed that the ethanol extract of pomegranate peel inhibited Bacillus cereus better than Bacillus subtilis and Bacillus atrophicus, and the minimum inhibitory concentrationof pomegranate peel extract against Bacillus cereus was 1 mg/mL.The pomegranate peel extract had a significant antibacterial effect on the overall biomass of the three kinds of Bacillus, and the total soluble sugars, soluble proteins, nucleic acid leakage, and electrical conductivity of the treatment group were significantly higher than that of the control, and their effects were enhanced with the increase of pomegranate peel extract concentration.The treatment of high concentration of pomegranate peel extract increased the total soluble sugar content of Bacillus cereus to 1.75 times of the control, the soluble protein content to 2.43 times, the nucleic acid leakage reached the peak at 6 h, which was 3.04 times higher compared to the control, and the electrical conductivity was 1.16 times higher, and the differences between the high concentration treatment groups and the control were all highly significant (P＜0.01).Combined with the scanning electron microscopy, the bacterial cells appeared to collapse and crumple, the cell boundary was blurred, the bacterial cells became shorter and thinner, and the cell contents overflowed, which proved that the pomegranate peel extract changed the morphology of the bacterial cells and destroyed the cell membranes, causing the leakage of the soluble total sugars, soluble proteins, nucleic acids, and other contents, achieving the antibacterial effect.

The metagenomic technology was used to analyze the microbial diversity and metabolism of natural fermented Suansun (NFS) and Lactobacillus plantarum fermented Suansun (LPS), and explore their key flavor factors.Results indicated that Firmicutes was a dominant phylum shared by NFS and LPS.At the genus level, Lactobacillus was the dominant genus in NFS, while LPS also contained dominant genera such as Weissella and Lactococcus. From the composition overlap of the two Suansun samples at the species level, it could be seen that the two samples were relatively similar in composition, but the diversity of LPS bacterial species was stronger.Through annotation and reconstruction of the key metabolic network in the Kyoto Encyclopedia of Genes and Genomes, it was found that carbohydrate and amino acid metabolism were the main metabolites of Suansun.Genes such as Escherichia coli K-12 MG1655 and Escherichia coli K-12 W3110 were believed to be closely related to lactate formation.Genes, such as botulinum toxin BKT015925 and fecal clostridium ATCC 25775, had been annotated to be associated with tryptophan metabolism, which were closely related to the characteristic sour odor of Suansun.In addition, LPS could inhibit the unpleasant odor of Suansun by inhibiting cysteine and methionine metabolism (ko00270) and tyrosine metabolism (ko00350).The results can provide a theoretical basis for the control of the fermentation flavor quality of Suansun.

To further explore the high added value of Sargassum fusiforme instant powder, the total phenols and flavonoids contents, as well as and the of DPPH, hydroxyl, oxygen and ABTS free radical scavenging ability of S. fusiforme instant powder were analyzed and determined.Further, using the Caenorhabditis elegans as a model, the antioxidant effect of S. fusiforme instant powder was evaluated by measuring its effects on lifespan, reproductive capacity, exercise ability, lipofuscin, heat stress, oxidative stress, in vivo antioxidant enzyme activity and accumulation of malondialdehyde and reactive oxygen species of C.elegans.The results showed that the total phenols and flavonoids contents of instant powder were 72.64 (GAE mg/g) and 52.97 (RE mg/g), respectively.Instant powder could significantly scavenge DPPH, hydroxyl, oxygen and ABTS cation free radicals in a dose-dependent manner.The results of C.elegans experiments showed that compared with the blank control group, the low-dose group (0.5 mg/mL), medium-dose group (1.0 mg/mL) and high-dose group (1.5 mg/mL) of instant powder could increase the average lifespan of C.elegans by 6.7%, 14.12% and 18.87%, respectively.S. fusiforme instant powder could reduce the lipofuscin accumulation and reproductive capacity in C.elegans, improve the movement ability of C.elegans, and improve the repair ability of C.elegans under oxidative stress and heat stress oxidative damage.In addition, S. fusiforme instant powder can significantly increase the activities of superoxide dismutase, glutathione and catalase in C.elegans, and reduce the accumulation of malondialdehyde and reactive oxygen species, showing significant antioxidant activity.

Alcoholic liver disease is one of the major causes of liver damage in China, and finding ways to improve alcohol-induced liver injury is critical.This study aimed to explore the therapeutic effects of Hovenia dulcis fruit peduncle polysaccharides (HDPs) on acute alcoholic liver injury in mice and its mechanisms.Male C57BL/6 mice were fed alcohol intragastrically for 15 days to establish an acute alcoholic liver injury mouse model.The experiment was divided into four groups (n=20), including a control group, an 11.4 μL alcohol group, a 114 μL alcohol group, and an HDPs (100 mg/kg) + 114 μL alcohol group.Serum biochemistry, histopathology, enzyme-linked immunosorbent assay, and metabolomics techniques were used to assess the effects of HDPs on blood lipids, liver function, inflammatory factors, and bile acid metabolism, as well as the expression of related genes (cyp7a1, fxr, and fgf15).Results showed that HDPs significantly reduced blood lipid levels in alcohol-exposed mice, alleviated pathological liver injury and glycogen consumption caused by alcohol, reduced the levels of pro-inflammatory cytokines interleukin-4, interferon-γ, and tumor necrosis factor-α, and improved the disorder of bile acid metabolism in alcohol-exposed mice.The results indicated that HDPs, as a natural active substance, had therapeutic effects on alcoholic liver injury, which may be achieved by regulating blood lipids, anti-inflammatory, and bile acid metabolism pathways.The study provides theoretical support for the application of Hovenia dulcis in functional food.

The objective of this study is to investigate the preparation technology and hypoglycemic effect of a new composite beverage based on sea red rice anthocyanins and oyster peptides.Using sea red rice anthocyanins and oyster peptides as raw materials, with the addition of steviosides as flavoring agents, the beverage preparation technology was optimized through single-factor experiments and orthogonal experimental designs.The effects of stabilizer content and storage conditions on the stability of the beverage were evaluated, and the inhibitory activities against starch digestive enzyme (α-glucosidase and α-amylase) were analyzed in vitro.In addition, the in vivo hypoglycemic effect of the beverage was investigated in type 2 diabetes mellitus mice model.The results showed that the optimal preparation process of the new composite beverage based on sea red rice anthocyanins and oyster peptides was as follows:1% of oyster peptides, 0.8% of anthocyanins, 0.1% of stevioside, 0.15% and 0.2% of Carboxymethyl Cellulose-Na and pectin, respectively.The composite beverage should be stored at low temperature.It had a strong inhibitory effect on α-glucosidase and α-amylase, and could effectively improve symptoms of type 2 diabetes mellitus mice, such as hyperglycemia, insulin resistance, difficulty in glycogen synthesis, and tissue damage.This study provides a method for preparing a new composite beverage based on sea red rice anthocyanins and oyster peptides, and the final beverage could effectively exert hypoglycemic effect, providing new ideas for the research and development of hypoglycemic functional beverages, and helping to promote the development of China’s functional beverage market.

This study aimed to investigate the effect of CO₂ anesthesia on the quality and protein characteristics of grass carp during storage.Four slaughter methods including percussion-direct gutting, percussion-tail cutting, CO₂ anesthesia-direct gutting, and CO₂ anesthesia-tail cutting were set up.Texture characteristics, total volatile basic nitrogen value, trichloroacetic acid soluble peptide content, total sulfhydryl and carbonyl content, cooking loss, Ca²⁺-ATPase activity, and SDS-PAGE protein profile of grass carp during frozen storage were analyzed.Results showed that CO₂ anesthesia could delay the degradation of protein and non-protein nitrogen compounds to some extent, maintain the water-holding capacity of muscle, and delay the oxidation of myofibrillar protein.The change rate of hardness and springiness of fish treated with CO₂ anesthesia-tail cutting was lower during frozen storage in comparison with other three treatments.According to the changes in quality and protein characteristics of fish during frozen storage, CO₂ anesthesia-tail cutting was recommended as the preferred slaughter method of grass carp.

Because of the high content of unsaturated fatty acid and easy to oxidize, beeswax fish oil oleogel requires a high preservation temperature, and its preservation temperature has been increasingly studied in recent years.In this study, the beeswax fish oil oleogel prepared with sardine oil as the base oil and beeswax as the gelling agent was used to investigate the effects of different preservation temperatures (-80, -18, 4 and 25 ℃) on the appearance of the beeswax fish oil oleogel, the oil-binding capacity (OBC), the hardness, the gel strength, the rheological properties, and the microstructure of the gel.The OBC at 4, -18 and -80 ℃ all reached more than 99%.Except for -80 ℃, the hardness, gel strength, and elastic modulus of the beeswax fish oil oleogel increased with the decrease in the storage temperature.The crystal structure of beeswax was densely arranged at the storage temperature of 4 ℃.Compared with the control lard, the beeswax fish oil oleogel preserved at 4 ℃ had good mechanical properties and melting characteristics of plastic fat and was energy-saving than preserved at -80 ℃.The present study provides data support to produce ω-3 fatty acid-rich beeswax fish oil oleogel by finding the optimal storage temperature for beeswax fish oil oleogel.

To enhance the stability of natural anthocyanins in the indicator membranes, grape-skin red (GSR) synthetic microcapsules were embedded with gelatin (GEL) and chitosan (CS) as wall materials and incorporated into potato starch (PS) and peanut shell cellulose (PSC) to prepare PS/PSC GEL/GSR/CS indicator films.The film properties were tested and analyzed, and the indicator films were applied in freshness monitoring of South American white shrimp.The results showed that when microencapsulation, peanut shell cellulose, and potato starch were used to prepare the composite film in the mass ratio of 2∶3∶50, the film was relative to the PS/PSC/GSR film, and the grapheme-red microencapsulation could increase the tensile strength of the indicator film from 11.95 MPa to 13.25 MPa, and the melting point was increased by 11 ℃, and the film could be stored at 4 ℃ (refrigerated), protected from light, and in 30% RH environment.It could be stored at 4 ℃ (refrigerated), protected from light and 30% RH for 15 days without obvious color difference and showed very high pH color response.The indicator film in the South American white shrimp freshness monitoring to verify the applicability of the color of the indicator film with the shrimp deterioration showed red-gray-yellow changes, the shrimp volatile saline nitrogen and other corruption index changes with the indicator film chromaticity value changes in the same trend, the color difference was visible, and would be extended for two days of color stability.Therefore, the freshness indicator film has high stability and has a promising application in the food field.

To prepare an indicator label with good sensitivity to the freshness of fresh milk, butterfly pea flower anthocyanins (BPA), mulberry anthocyanins (MA), and purple potato anthocyanins (PPA) were added individually into the soluble starch and polyvinyl alcohol substrates to make composite indicator films, and their structure, performance, and indicator sensitivity were characterized.Results showed that all three anthocyanin solutions could exhibit different colors at different pH, and BPA had the most significant color change and the best stability.In each composite film, all three types of anthocyanins had physical interactions with the substrate and managed to maintain the pH color sensitivity of anthocyanins.After adding MA, the composite film still maintained a dense microstructure, while the elongation at break significantly increased (P<0.05).However, the addition of BPA and PPA caused the formation of pores or cracks in the film, leading to a decrease in its mechanical properties.Meanwhile, the influences of anthocyanins on the solubility, swelling, and water vapor permeability of composite films were also related to the type of anthocyanins.After contacting three types of composite films with fresh milk at room temperature, the composite films containing BPA and MA showed visible changes of color when the total bacterial count in milk exceeded the standard, showing the potential to be used as indicators of milk freshness.

To investigate the structural characteristics of pectin from Premna microphylla Turcz (PMTP), hot water was used to extract water-soluble pectin (WSP).Following gradual ethanol precipitation, high-purity water-soluble pectin with 50%-55% ethanol-induced precipitation (WSP-55) was collected.The molecular structure of WSP-55 was analyzed using Fourier transform infrared spectroscopy (FT-IR), high-performance size exclusion chromatography (HPSEC), high-performance anion exchange chromatography-pulsed amperometric detector, gas chromatography-mass spectrometry, nuclear magnetic resonance spectroscopy (NMR).HPSEC results showed that the relative molecular weight of WSP-55 was 139 kDa.Combined with FT-IR and methylation analysis, WSP-55 was a low-methoxyl pectin containing abundant homogalacturonan (HG) domain and a small amount of rhamnogalacturonan-I (RG-I) domain.The results of NMR analysis showed that the HG domain of WSP-55 consisted of a molar ratio of 4∶1 of →4)-α-GalpA-(1→ and →4)-α-GalpA-6-O-Me-(1→, while the main chain structure of the RG-I domain was composed of the repeating unit[→2)-α-Rhap-(1→4)-α-GalpA-(1→]_n, with the Araf and Galp sugar residues were found on the side chain of RG-I.This study would lay a foundation for the study of the structure-activity relationship of PMTP and provide theoretical support for its effective application in the biomedical and food industries.

The process of starch modification not only eliminates some unfavorable physical and chemical properties of natural starch, but also provides new product properties.Modified hydroxypropyl distarch phosphate (HDP), distarch phosphate (DP) and acetylated distarch adipate (ADA) are more resistant to high and variable temperatures, factors such as shear or low pH, and are often used as stabilized crosslinking starches for food processing to enhance the performance of pasta and bakery products.Four typical high quality modified starches were explored, with rheological properties, hardness, protein secondary structure, color and sensory indexes.The quality characteristics and hardening improvement effects of HDP, DP, ADA and pre-gelatinized acetylated distarch adipate (PADA) with different proportions (4%, 8%, 12%, 16%) on protein bars were studied.The results showed that 4% of HDP, DP, ADA, and 8% of PADA significantly reduced the hardness of protein bars and improved the sensory quality of the products.This study provides theoretical support for the feasibility and market value of the transformation of refined starch processing industry.

Eucommia leaves have been proved to be edible substances that can be used as medicine and food, and they are rich in active ingredients and have a promising development prospect.In this paper, the effects of different additions of eucommia leaf micro-powder on the colour, texture, microstructure, moisture distribution, protein secondary structure, pasting and thermal properties of starch and in vitro digestion of the biscuits were investigated by using a colour difference meter, a physical property analyser, a scanning electron microscope, a low-field nuclear magnetic resonance imaging analyser, a Fourier mid- and far-infrared spectrometer, an X-ray diffractometer, a differential scanning calorimetry instrument, and the establishment of an in vitro digestion system.The results showed that eucommia leaf micro-powder improved the colour of the biscuits, affected the overall nutrient composition, resulted in increased chewiness, increased uniformity of the pore structure, and improved textural properties.At the same time, eucommia leaf micro-powder improved the combination of starch and free water in the biscuits, which led to a decrease in the free water content;increased β-folding and irregular curling, which affected the stability of the secondary structure of proteins;prolonged the pasting time of the starch in the biscuits, lowered the rate of hydrolysis of the starch, and inhibited the increase in blood glucose value;and also found the highest composite scores and better flavours when the addition amount was at 1% by organoleptic analyses.Finally, it proved that the micro powder of Eucommia bark leaves could improve the biscuits, and provided a theoretical and practical basis for the development of functional biscuits.

Sargassum is a common brown alga in China, which has many biological activities and broad application prospects in the fields of functional food.Ultrasonic-assisted extraction of Sargassum polysaccharide was optimized through single-factor experiments.Subsequently, the obtained polysaccharide was characterized by size-exclusion chromatographic analysis (SEC) coupled with multiangle laser light scattering (MALLS) detection and refractive index (RI) detector (SEC-MALLS-RI), ion chromatography, fourier transform infrared spectrometer, and nuclear magnetic resonance. The optimal ultrasound-assisted extraction conditions for Sargassum polysaccharide were as follows:ultrasonic frequency of 28 kHz, mass-liquid ratio of 1∶60 (g∶mL), extraction temperature of 70 ℃, and extraction time of 180 min.Under the optimal condition, the extraction rate was 9.73%, which was mainly composed of fructose, uronic acid, fucose, galactose, and mannose, with molar ratio of 56.6∶16.2∶8.4∶8.3∶6.8, respectively.SEC-MALLS-RI displayed that Sargassum polysaccharide was a highly dispersed macromolecule polymer with a molar weight of 1.18×10⁷ (±3.13%) g/mol.On the other hand, according to ¹H NMR spectra, the type of glycosidic linkage was mainly the β-glycosidic bond.Meanwhile, X-ray diffraction demonstrated Sargassum polysaccharide was a semi-crystalline polymer, while scanning electron microscope and atomic force microscope observation suggested polysaccharide chains were prone to be associated with weak and small aggregates with homogeneous morphology.Moreover, Sargassum polysaccharide showed desirable ferric ion-reducing capacity and free radical scavenging ability with a good dose-response relationship.This study demonstrated that the yield of Sargassum polysaccharide was effectively improved by the ultrasonic-assisted extraction method, providing a theoretical reference for the development and high-value utilization of Sargassum resources.

This study investigated the effects of superfine grinding technology on the physical, chemical, structural, and nutritional properties of safflower powder.The color, bulk density, hydration characteristics, fluidity, total flavonoids, and cation exchange capacity of safflower powder with different particle sizes were analyzed in this study.The effects of structure were explored through scanning electron microscopy and X-ray diffraction analysis.The results indicated that as the particle size decreases, there was an observed increase in filling and hydration properties (P<0.05).The bulk density, water solubility, water-holding capacity, and swelling capacity of the smallest particle size (D₅₀=73.68 μm) are 40.43%, 10.02%, 49.23%, and 17.64% respectively, higher than those observed at the largest particle size (D₅₀=197.90 μm).The reduction in particle size could enhance the fluidity, cohesion angle, and sliding angle of safflower pollen, resulting in a decrease from 42.11° to 34.63° for the cohesion angle and from 45.02° to 28.04° for the sliding angle.The superfine grinding did not alter the crystal structure of safflower pollen.Furthermore, in terms of nutritional value, the dissolution of total phenols and total flavonoids increased from 5.66 and 14.27 mg/g to 7.71 and 15.22 mg/g, respectively.The cation exchange capacity increases by 14.28%.The results demonstrated that superfine grinding technology can enhance the physicochemical and functional properties of safflower powder through particle size reduction, providing a theoretical foundation for the advanced processing of safflower pollen.

The utilization of by-products is crucial for the development of navel orange industry.In this study, the extraction process of pectin from navel orange peels (NOP) was optimized using response surface analysis, and the molecular weight, structural characteristics and rheological properties of NOP were investigated.The optimal extraction conditions for NOP were determined as extraction temperature of 90 ℃, extraction time of 110 min, solid-liquid ratio of 1∶29(g∶mL), and pH 1.4, resulting in an extraction yield of 28.99%.NOP was characterized as a low-branched, low methoxyl pectin (LMP) with a major composition of linear homogalacturonan (HG) and a molecular weight of 135.4 kDa.It presented as a compact random coil in solution.Rheological analysis demonstrated that NOP behaved as a shear-thinning pseudoplastic fluid in aqueous solution, showing concentration dependence and sensitivity to temperature and alkaline environments.However, it exhibited good thermal reversibility and acid resistance.Dynamic rheology revealed that NOP possessed excellent gelling property, which could be enhanced by increasing concentration and low concentrations of Ca²⁺, but diminished by high temperature and concentration of Ca²⁺.Overall, NOP exhibited good thickening and gelling properties, providing a theoretical basis for its applications and the development of high-value products derived from navel oranges.

This paper discussed the effects of pulsed light treatment and thermal treatment on the antioxidant activity of tomato juice and related endogenous enzymes and functional components.The results showed that pulsed light treatment could activate phenylalanine ammonialyase (PAL) and catalase (CAT), inhibit superoxide dismutase (SOD), and simultaneously reduce the content of vitamin C and increase total acid content (P<0.05).There was a high correlation between the content of vitamin C and total acid, as well as enzyme activity, with pulse energy (R²>0.850 0), conforming to first-order reaction kinetics (R²>0.880 0), and its effects were better than that of thermal treatment (P<0.05).Additionally, both pulsed light and thermal treatment could enhance the ability of tomato juice to scavenge ·OH radicals, but reduce the scavenging capacity for DPPH, ·O₂^-, and reducing power (P<0.05).Compared to thermal treatment, pulsed light treatment better maintained the original nutrients and activity of tomato juice.This study provides a theoretical basis for the application of pulsed light in fruit and vegetable juices.

This study isolated and identified a “golden flower” fungus strain AH10 in Fu brick tea from Anhua, Hunan province and analyzed the quality of tea leaves fermented by this fungus.The strain AH10 was identified as Aspergillus cristatus based on the morphological characteristics and multilocus phylogenetic analysis of β-tublin (tub2), Calmodulin (CaM), and RNA polymerase Ⅱ (RPB2).The sensory evaluation results showed that abundant golden flowers emerged on the surface of tea leaves fermented by AH10, with a richer “fungal flower” aroma and a mellower and thicker taste.It had a similar taste and aroma to that of soup of naturally fermented Fu brick tea.Sixty-seven volatile compounds (VOCs) were detected in tea samples fermented by AH10 using headspace gas chromatography ion mobility spectrometry, including 11 key different flavor compounds[variable importance in projection (VIP)>1].There was a significant increase of 1-octen-3-ol, trans-2-hexenal and methyl salicylate in the fermentation tea, which were important contributors to the “fungal flower” aroma.Eighty-nine metabolites were detected using GC-MS, including 12 down-regulated metabolites and 6 up-regulated metabolites (VIP>1, P<0.05), such as D-sorbitol, glyceric acid, and gallic acid.This study can provide a theoretical basis for the selection of “golden flower” fungi and the improvement of fermented-tea quality.

Phenolic compounds in wine are directly related to their stability during aging, their composition and content significantly influence wine quality.Utilizing white and rosé sparkling wines as experimental samples, this study investigated the correlation between phenolic compounds and sensory quality during an 18-month aging process. HPLC-MS, CIElab method, and foam analyzer were employed to determine monomeric phenolics, color parameters, and foam parameters during the aging process, respectively, followed by correlation analysis.Results indicated that the overall content of monomeric phenolics in rosé sparkling wine was 1.71-1.97 times higher than that in white sparkling wine, while the foam parameters of white sparkling wine were significantly higher than those of rosé sparkling wine.With prolonged aging, wine color deepened, and yellow hues significantly increased while foam parameters significantly decreased.Overall, phenolic compound content exhibited a significant negative correlation with foam characteristics, with gentisic acid content showing significant correlations with maximum foam height (r=-0.61, 0.01<P<0.05) and stable foam height (r=-0.70, P<0.01).These findings indicated inhibiting the content of phenolic compounds within an appropriate range, with total phenol content around 0.30 g/L, may contribute to producing sparkling wines with full color and stable dense foam, thereby offering guidance for the production of high-quality sparkling wines.

To elucidate the key volatile compounds influencing the olfactory characteristics of oyster sauce products, 15 commercially accessible oyster sauces were applied in this investigation.Quantitative descriptive analysis and electronic nose were employed to compare their discernible sensory distinctions.Gas chromatography-mass spectrometry was utilized to scrutinize the distinctive flavor compounds present in the products, while partial least squares regression analysis and the Pearson correlation method were applied to ascertain the relationship between sensory perceptions and volatile compounds affecting the odor profile of oyster sauce.The findings demonstrated the efficacy of sensory evaluation and electronic nose in discriminating the olfactory profiles of various oyster sauce products.Moreover, the sauce aroma of oyster sauce products exhibited significant positive correlations with the levels of 3-methyl-1-butanol, 2-methoxyphenol, dimethyl disulfide, and phenylacetaldehyde (P<0.05).A statistically significant positive correlation was observed between the roasted aroma and the levels of trimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine (P<0.05).Additionally, the oyster aroma and fishy odor were found to be positively correlated with octaldehyde, but the correlation with the later was higher.This study lays a foundation for establishing a scientific framework for evaluating the odor quality of oyster sauce products.

The techniques of high performance liquid chromatography, E-tongue, E-nose, and gas chromatography-ion mobility spectrometry(GC-IMS) were employed to investigate the impact of hot air drying on the flavor profile of oysters, aiming to elucidate the distinct flavor variations observed in oysters before and following the drying process.Compared to fresh oyster aqueous extracts, the dried extracts exhibited a darker hue, enlarged particle size with a more uniform distribution, and a 4.26% rise in the proportion of molecules with a molecular weight of less than 5 kDa.Additionally, the content of fresh and sweet amino acids increased by 16.46 mg/g, flavor nucleotides amounted to 3 mg/g, betaine measured 1.81 mg/g, glycogen increased by 0.89 g, and the short peptide content surged to approximately 2.4 g per 100 g of the aqueous extract, all indicating a heightened taste potential.The results from the E-nose and GC-IMS analyses revealed the presence of 41 volatile compounds in both aqueous extracts.Among these, 19 were aldehydes, and the relative content of ketones surged by 7% post-drying, imparting a distinctive fruity aroma that constituted the primary scent characteristic of the dried oyster aqueous extracts.However, in cooked meat, the intensity of valeraldehyde and cis-4-heptenal, which contribute to sweet grassy and fatty aromas, diminished.Conversely, hexanal (associated with a fishy, crude oil, and grassy aroma), heptanal (crude oil scent), benzaldehyde (almond, cherry, and nut aroma), and 2-hexenal (herbaceous aroma) emerged alongside other aromatic compounds.Our comprehensive study offers valuable foundational insights for flavor modulation, enhanced processing techniques, and the efficient utilization of dried oysters.

This study investigated the effects of crude polysaccharide from jujube on the fermentation properties of dough and the color, texture, crumb structure, flavor, and sensory properties of steamed breads, and the flavor differences of steamed breads were analyzed using multivariate statistical analysis.Results showed that the addition of 0.2%-1% crude polysaccharides increased the gas production of dough, improved the hardness and elasticity of the steamed breads, and enhanced their fermentation volume, porosity, and average stomatal area of the steamed breads.Compared with the control, the contents of volatile flavor compounds in steamed breads added crude polysaccharide decreased, such as 3-octene-1-ol, 2-propanol, butanal, and 2-pentylfuran, while there was no significant difference in the contents of other flavor compounds.Furthermore, 0.2%-1% crude polysaccharides increased the total sensory score of steamed breads.The comprehensive results showed that the addition of crude polysaccharide had a positive effect on the quality of steamed breads, and they provided a theoretical basis for the application of crude polysaccharide in food processing.

This study aimed to screen the yeast strains with high gas production speed and good freezing resistance and improve the sensory deterioration of raw dough caused by freezing.In this study, five yeast strains were isolated from old dough, and the freezing tolerance of the yeasts was evaluated in terms of growth curve, fermentation power, and survival after freezing.The effects of the isolated yeast and the commercial yeast agent on frozen dough were compared and analyzed by texture characteristics, volatile flavor components, and sensory measurement.Results showed that Y2 of the 5 strains had good frost resistance and gas production, and the dough with Y2 added had better chewability and hardness, which could maintain the texture of the product.Molecular biology identified Y2 as a strain of Saccharomyces cerevisiae, and the differences in sensory and flavor substances between Y2 and three commercially available yeast preparations of dough frozen under the same conditions were compared.The textural and organoleptic results showed that the freeze-tolerant yeast Y2 had an improved effect on the quality of dough after freezing, and was significantly better than the commercially available common yeast in terms of chewiness and organization.On the difference of volatile flavor components, 54 flavor components were detected in group Y2, including 14 alcohols, 13 aldehydes, 14 esters, 7 acids, 1 ketone, and 5 alkanes.Partial least squares discriminant analysis (PLS-DA) was used to analyze the relative contents of 21 kinds of aroma substances in each group of dough.According to the weight coefficient of variables (VIP≥1), 11 major flavor contributing substances were screened.The key flavor components of the Y2 and S3 groups had some similarities, and the key flavor components were more abundant.Using the relative content to plot the heat map, the content of key flavor substances in Y2 was significantly higher than that of the other groups, and the application effect and flavor promotion in the frozen dough were better than that of the common yeast agents.

L-valine, an essential branched-chain amino acid, is widely utilized in the food, pharmaceutical, feed, and cosmetic industries owing to its diverse physiological functions.With the advancement of microbial metabolic engineering technology, the fermentation process of engineered bacteria has emerged as the preferred method for producing L-valine due to its high efficiency, lack of pollution, and environmental protection potential.This study reviewed the metabolic engineering methods and strategies for creating high-yielding strains of L-valine, as well as the L-valine biosynthesis pathway from Corynebacterium glutamicum.It also provided references for pertinent researchers looking to enhance L-valine production.

Dietary fiber can regulate the level of bile acids in the body, and bile acids are reabsorbed, metabolized and excreted through the intestinal tract.The biological activity of dietary fiber is also closely related to the intestinal tract.Although in vitro and in vivo experiments in recent years have proved the interaction between dietary fiber and bile acids, the regulatory mechanism between the two is still poorly understood.This report summarized the mechanisms of dietary fiber binding bile acids in the small intestine, regulating the expression of bile acid receptors and the structural changes of gut microbiota.The report provided new ideas for the subsequent research on the development of dietary fiber and the mechanism of regulating bile acids, and formulated new targeted regulation strategies.It provides new ideas to further investigate the mechanism of action between bile acids and dietary fibers, new references for precise regulation of bile acid metabolism by dietary fibers in vivo, and new strategies for targeted regulation.

A long-term high-fat diet (HFD) exerts profound effects on lipid metabolism in the human body, leading to obesity, nonalcoholic fatty liver disease, diabetes mellitus type 2, and other related disorders.Recent research has shed light on the diverse physiological regulatory functions of polyphenols, encompassing antioxidation, anti-inflammation, blood lipid reduction, and immune enhancement.This paper provides a concise discussion on the underlying mechanisms through which polyphenols ameliorate HFD-induced lipid metabolism disorders while also exploring their impact on associated diseases.The regulatory effect primarily involves modulation of glycerol and fatty acid metabolism, upregulation of proteins implicated in the insulin signaling pathway, regulation of intestinal microflora composition and abundance as well as modulation of inflammatory stress response.These findings are expected to offer valuable insights into comprehending the mechanism underlying polyphenol-mediated regulation of lipid metabolism disorders and provide a theoretical foundation for developing functional dietary products enriched with polyphenols.

Inflammatory bowel disease (IBD) is a chronic, recurrent inflammatory disorder that damages the gastrointestinal tract.The gut microbiota, which resides in the human gastrointestinal tract, plays a crucial local and systemic role and is closely related to the onset and progression of IBD.Faecalibacterium prausnitzii is a type of gut symbiotic bacteria whose extracellular vesicles and metabolic products have been shown to ameliorate colitis, but the specific mechanisms of action remain unclear.This article reviews the effects of F. prausnitzii and its metabolites on intestinal barrier function in relation to colitis and discusses the challenges and issues associated with the application of next-generation probiotics, fecal transplantation, and butyrate therapy for treating IBD, aiming to provide theoretical references for the treatment of IBD.

Selenium (Se) is an essential trace element for the human body, which has functions such as antioxidant, antitumor, and enhancing immune.Lactic acid bacteria are widely recognized as a suitable carrier that can accumulate and covert Se from inorganic to organic and elemental forms, thereby improving the bioavailability and absorption of selenium.This article summarizes the mechanism of selenium enrichment in selenium-enriched lactic acid bacteria, how lactic acid bacteria convert inorganic selenium, and the chemicals involved in the process.The article also explores the distribution and characteristics of selenized products in different structures of microbial cells, as well as the effects of selenization on the growth and nutritional value of the strain, with the aim of providing a theoretical basis for the further development and application of selenium-enriched lactic acid bacteria.

Aflatoxin M₁ is a hydroxylated metabolite derived from aflatoxin B₁ in mammalian livers, exhibiting carcinogenic, immunotoxic, genotoxic, and mutagenic properties.It poses a significant threat to consumer safety as it is challenging to eliminate from milk and dairy products.Therefore, the development of rapid and sensitive on-site detection technologies is of paramount importance.Biosensors are widely used for the detection of mycotoxins, because of their advantages of portability, sensitivity, and intelligence.This article reviewed the research progress of aflatoxin M₁ biosensor based on signal amplification strategy in recent years, discussing the advantages and limitations of signal amplification strategy in biosensor applications.This review also provided an outlook on the development trend of signal amplification strategy.

With the proposal of building a characteristic food industry system in the national "14th Five-Year Plan", the traditional food processing technology is also changing to build a diversified and innovative technology.Food 3D printing technology has the advantages of personalized customization, high processing precision, balanced nutrition and green production, and provides new ideas for the construction of innovative food processing methods.Through investigation and analysis, this paper introduces the latest progress of current food 3D printing, systematically discusses the application and advantages of food 3D printing technology in processing accuracy, nutritional balance, on-demand production, and green production, and points out the challenges faced by current food 3D printing technology, such as the improvement and optimization of equipment, the expansion of food ingredients and economic benefits.Finally, this paper looks forward to the future development trend and direction of food 3D printing technology, aiming to provide reference for the construction of diversified innovative food processing technology.

Reducing sodium intake continues to be an important health issue of global concern, and meat products are one of the main sources of sodium in food.Low-sodium strategies for processing meat products were being explored.Processing technologies (ultrasonic, high pressure, microwave, magnetic field, etc.), salty substitutes (salty amino acids, salty peptides, umami peptides, etc.), and substitutes for improving tissue texture (dietary fiber, soya proteins, carrageenan, etc.) were reviewed in the development of low-sodium meat products and their effects on quality.The combination methods for sodium reduction were beneficial in maintaining the quality by altering the structure of the meat products.Low-sodium meat products have problems of product clean labels, chemical substances, and microbial safety.Further, it is necessary to combine consumers communication and food labels to promote the acceptance of low-sodium meat products.