Menaquinone-7 (MK-7), an important bioactive form of vitamin K₂, exhibits broad application prospects in promoting bone health, preventing cardiovascular diseases and treating neurodegenerative disorders.In this study, Bacillus subtilis 168 was selected as the chassis strain, and a multi-module metabolic engineering strategy was employed to optimize the MK-7 biosynthetic pathway systematically.Initially, key genes in competing branch metabolic pathways, including the isochorismate-pyruvate lyase gene (dhbB), aromatic amino acid biosynthesis genes (trpE/aroH), and the phosphotransferase system (PTS) glucose transporter gene (ptsG), were knocked out to minimize precursor diversion.Subsequently, the efficiency of the electron transport chain was enhanced by overexpressing the NADH dehydrogenase gene (ndh) and the terminal oxidase gene (sdhCAB), thereby facilitating electron transfer.Furthermore, the heterologous dxs gene from Agrobacterium tumefaciens was introduced, and the endogenous rate-limiting enzyme gene hepS was overexpressed to increase the flux of the methylerythritol 4-phosphate (MEP) pathway.Ultimately, the engineered high-yielding strain S13 achieved an MK-7 titer of (123.90±6.52) mg/L in shake-flask fermentation.Upon scale-up validation in a 3 L fermenter, the production further increased to 242.38 mg/L, laying a solid foundation for the industrial-scale microbial fermentation of MK-7.

Xanthosine, also known as 9-ribofuranosyl-3,9-dihydro-1H-purine-2,6-dione, is a nucleoside composed of xanthine and a ribosyl group.Currently, xanthosine is synthesized through plant extraction or chemical synthesis, both of which suffer from low yields and high production costs.To develop a plasmid-free xanthosine-producing strain, this study systematically engineered the metabolic pathways of the wild-type Escherichia coli W3110.Initial strategies aimed at enhancing precursor supply by overexpressing the glycine hydroxymethyltransferase gene (glyA), the aspartase gene (aspA), and the carbonic anhydrase gene (can) to increase intracellular glycine, L-aspartate, and CO₂, and blocking the conversion of xanthosine monophosphate (XMP) to guanosine monophosphate (GMP) by deleting the guaA gene did not lead to detectable xanthosine production.Significant production was first achieved by overexpressing a feedback inhibition-resistant mutant of phosphoribosyl pyrophosphate (PRPP) synthetase (prs_Eco^D128A) and deleting the purine repressor gene (purR), resulting in 1.05 g/L xanthosine.Introducing a feedback-resistant PRPP amidotransferase mutant (purF_Baz^K326Q) from Bacillus amyloliquefaciens alleviated a key rate-limiting step in de novo purine biosynthesis and increased production to 1.43 g/L.Further enhancement of the pentose phosphate pathway via overexpression of the glucose-6-phosphate dehydrogenase gene (zwf) and transketolase gene (tktA) elevated xanthosine titer to 2.28 g/L.Expression of the heterologous purine operon (purEKBCSQLFMNHD) further boosted production to 2.85 g/L.To reduce xanthosine degradation, the genes ppnP and deoD, both encoding purine nucleoside phosphorylases, were knocked out, resulting in a final titer of 4.00 g/L.After 26 hours of fed-batch fermentation in a 5 L bioreactor, the engineered strain XL12 achieved a xanthosine titer of 10.25 g/L, representing the highest reported production of xanthosine via microbial fermentation to date.

Kluyveromyces lactis is a non-conventional yeast with many advantages, but there is relatively little research on its endogenous expression regulatory elements.To expand the promoter elements of K.lactis, this study systematically evaluated the fluorescence expression levels of 60 endogenous promoters based on transcriptome analysis, GFP expression and screening, and selected 21 highly expressed promoters.Further, the six promoters with the highest fluorescence intensity (P_HSP12, P_GAP1, P_ADH1, P_TEF1, P_SED1, P_SSA2) were selected to express the K.lactis lactase gene on the genome.The results showed that the lactase activities expressed by the promoters P_HSP12, P_GAP1, P_ADH1, and P_TEF1 were 5.2, 3.4, 2.3, and 2.2 times higher than that expressed by the natural promoter P_LAC4, respectively.Through the analysis of the functional regions of the promoters, the core promoter and upstream activation sequence (UAS) of the six strong promoters were determined, and hybrid promoters composed of different UAS and core promoters were constructed.This study provides effective tools for the gene expression regulation and efficient expression of heterologous proteins in K.lactis, which will be conducive to expanding the application potential of K.lactis in the field of biotechnology.

Oleuropein, a natural secoiridoid glycoside polyphenolic compound, exhibits various biological activities including antioxidant, anticancer, hypoglycemic, and cardioprotective effects.It is widely used in food, health products, pharmaceuticals, and cosmetics.Currently, oleuropein is primarily obtained through plant extraction;however, this method faces challenges such as low extraction efficiency, complex purification processes, and dependence on natural conditions.Microbial synthesis of oleuropein is an alternative solution with great industrialization prospects.Nevertheless, the biosynthetic pathway of oleuropein remains incompletely elucidated.To identify key enzymes in oleuropein biosynthesis and clarify its pathway, this study first hypothesized that the hydroxylation of ligstroside to oleuropein could be catalyzed by either polyphenol oxidase (PPO) or cytochrome P450 enzymes.Through the analysis of Olea europaea transcriptome data, three candidate PPO genes were obtained.These genes were cloned into the pET-28a vector and heterologously expressed in Escherichia coli BL21(DE3).Subsequent in vitro enzymatic assays revealed that OePPO3 catalyzes the conversion of ligstroside to oleuropein.Enzymatic characterization showed that OePPO3 has an optimal temperature of 10 ℃ and optimal pH of 6.0 when using ligstroside as a substrate, with the k_cat/K_m is (20.95±4.22) L/(mmol·min).The enzyme also hydroxylates other compounds (p-coumaric acid, salidroside, osmanthuside A, and osmanthuside B), indicating broad substrate specificity.This work advances the understanding of oleuropein biosynthesis and provides a key enzymatic component for microbial heterologous synthesis of oleuropein.

L-homoserine is an important non-proteinogenic amino acid with wide-ranging applications in the feed, pharmaceutical, and chemical industries.Currently, the synthesis of L-homoserine mainly relies on two technical routes:chemical synthesis and microbial fermentation.Among them, microbial fermentation has attracted considerable attention due to its environmental friendliness and cost-effectiveness, and is regarded as a promising approach for the green manufacturing of L-homoserine.Corynebacterium glutamicum, a food-grade industrial microorganism, has emerged as a promising host for L-homoserine production.However, current metabolic engineering efforts targeting C.glutamicum remain limited, and the achieved titers and yields of L-homoserine are still insufficient to meet the demands of industrial-scale applications.In this study, C.glutamicum was employed as the chassis strain for systematic metabolic engineering to construct a robust L-homoserine-producing cell factory.By eliminating degradation pathways and reconstructing the dual biosynthetic routes involving AspC and AspA, a basal chassis strain with L-homoserine biosynthetic capacity was first established.Subsequently, further improvements were achieved through enhancing precursor supply, fine-tuning the metabolic fluxes of the dual pathways, and optimizing NADPH regeneration.The final engineered strain, HOM21, achieved a titer of 95.8 g/L in a 5-liter bioreactor, with a production rate of 1.6 g/(L·h) and a glucose conversion yield of 0.45 g/g, representing the highest level of L-homoserine production reported for C.glutamicum to date.This study provides a comprehensive metabolic engineering strategy for the efficient biosynthesis of L-homoserine in C.glutamicum, elucidates key rate-limiting steps and their regulatory optimization, and offers theoretical and practical guidance for the industrial-scale green production of L-homoserine.

Arachidonic acid (ARA) plays a key role in infant cognitive and visual development.Enhancing ARA absorption efficiency can be achieved by structuring lipids using medium- and long-chain triglycerides (MLCT) as carriers.This study aimed to synthesize ARA-enriched MLCT through enzymatic interesterification of Schizochytrium sp.microbial oil with medium-chain triglycerides (MCT), using surfactant-imprinted lipase to improve catalytic activity.The optimal preparation conditions of bio-imprinted lipase were determined through single-factor experiments and orthogonal experiments as follows:Lipozyme 435 served as the catalyst, Tween 20 as the imprinting template, surfactant concentration at 50 mg/L, and buffer pH at 7.0.These conditions increased the lipase’s initial activity by 1.36-fold.For MLCT synthesis, the best reaction conditions included 6% (mass fraction) lipase addition amount, a 1.5∶1 MCT-to-microbial oil molar ratio, 70 ℃, and 6 h.The mass fraction of the final product contained 13.12% MCT, 66.80% MLCT, and 20.08% long-chain triglycerides (LCT).Notably, the molar fraction of MCFA at the sn-1,3 position was 58.13%, and the molar fraction of ARA at the sn-2 position was 15.61%.After BIL was reused for 7 times, the MLCT content still remained at 61.05%.The synthesized ARA-enriched MLCT demonstrates improved bioavailability, offering potential applications in functional foods and nutritional supplements for infants.

Rebaudioside D (Reb D), a natural high-intensity, low-calorie sweetener, serves as a crucial precursor for synthesizing Rebaudioside M (Reb M), offering significant commercial and health benefits.Research on Reb D is therefore crucial for advancing the development of high-quality sweetener.In this study, a dual-enzyme coupled system was established by constructing a recombinant Escherichia coli strain co-expressing glucosyltransferase EUGT11 and sucrose synthase AtSUS3.This system facilitated the recycling of uridine diphosphate glucose (UDPG), enabling the efficient bioconversion of Reb A to Reb D.Under optimized conditions in a 3 mL glycosylation reaction system containing 100 mmol/L NaH₂PO₄-Na₂HPO₄ buffer (pH 7.0), supplementation with 2.4 mg/mL crude enzyme extract, 1.2 g/L Reb A, and 60 g/L sucrose, followed by incubation at 30 ℃ for 20 h, resulted in a maximum Reb D yield of 1 205.81 mg/L, corresponding to an 86.06% conversion rate.This study significantly enhances the synthesis efficiency of Reb D and establishes a robust technical foundation for the cost-effective, large-scale production of high-purity steviol glycosides.

The study systematically elucidated the taxonomic relationship between Bifidobacterium adolescentis and Bifidobacterium faecale through whole-genome analysis.The strain CICC 10187R (JCM 19861)[synonym B.faecale] was resequenced for 16S rRNA gene sequence and whole-genome sequence, and performed phylogenetic analyses of 16S rRNA gene and whole-genome sequences, genome characterization comparative analysis, average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) analyses.The results show that phylogenetic analysis revealed that strain CICC 10187R clustered within the same clade as B.adolescentis ATCC 15703^T.The genome of CICC 10187R (GCA_039830185.1) is 2.20 Mb with a DNA G+C content of 59.07 mol%.The ANI, AAI, and dDDH values between CICC 10187R and B.adolescentis ATCC 15703^T were 97.87%, 97.91%, and 80.70%, respectively, all exceeding the species delineation thresholds.Furthermore, analysis of whole genome sequence of 620 related strains from the NCBI database confirmed the reclassification of CICC 10187R as B.adolescentis.B.adolescentis, as an important food strain, the identification of accurate taxonomic status is an important foundation for the functional study, safety evaluation and industrial application.This study provides robust scientific evidence for the taxonomic classification of B.adolescentis and serves as a valuable reference for related research and applications.

Oropharyngeal candidiasis (OPC) exhibits a high incidence in immunocompromised populations.A novel preventive strategy involves modulating host mucosal immunity to inhibit disease progression.Defensins and secretory immunoglobulins serve as the first-line defense at mucosal surfaces and are critical effector molecules against pathogenic infections.This study aimed to screen oral commensal bacteria capable of regulating host antimicrobial secretion and elucidate their host-microbe interaction mechanisms in mucosal immunity.Using the HOK-16B oral keratinocyte model, this study screened 15 Ligilactobacillus salivarius strains and identified CCFM1417 as the most potent candidate.Its bacterial lysate was further evaluated in a murine OPC model infected with Candida albicans.Mechanistic studies revealed that CCFM1417 lysate activated the IL-17/IκBζ signalling pathway, upregulating murine β-defensin 3 (mBD3) expression to (30.69±6.35) pg/mg (2.25-fold higher than the model group).Concurrently, it synergistically elevated polymeric immunoglobulin receptor (pIgR) and secretory immunoglobulin A (SIgA) levels (1.57- and 1.94-fold increases, respectively), effectively preventing OPC onset.This study revealed the molecular mechanism by which saliva combined with L.salivarius CCFM1417 regulates the secretion of host mucosal antimicrobial substances through the IL-17/IκBζ signaling pathway, providing an important theoretical basis for the targeted treatment research of oropharyngeal candidiasis.

This study investigated the effects of Zanthoxylum bungeanum (ZB) on lipid metabolism in high-fat diet-induced obese mice and its potential mechanisms of action.An obesity mouse model was established using a high-fat diet and divided into a blank group, model group, and ZB low, medium, and high dosage groups over 8 weeks.Throughout the experiment, the body weight changes of the mice were monitored, and their feces were collected for 16S rDNA sequencing.At the experiments conclusion, serum, liver, adipose, and colon tissues were collected for analysis.Results indicated that intervention of ZB significantly reduced body weight, TG, and TC levels in obese mice,and simultanously repaired the adipose tissue hypertrophy,liver steatosis and intestinal barrier damage induced by a high-fat diet. 16S rDNA sequencing results showed that intervention of ZB restored the diversity of the intestinal microbiota in obese mice to a certain extent compared to the model group.β-Diversity analysis revealed that intervention of ZB significantly decreased the Firmicutes/Bacteroidetes ratio and increased the relative abundance of Lactobacillus, Romboutsia, Dubosiella, and Bacteroides, while reducing the relative abundance of the harmful bacterium Desulfovibrionaceae. Functional prediction and analysis of the intestinal microbiota suggested that ZB maintained body health by regulating metabolic functions, including carbohydrate metabolism, amino acid metabolism, and energy metabolism, in obese mice.The findings indicate that intervention of ZB effectively prevents obesity by regulating the disorder of the new intestinal flora in mice.

A long-term high-fat diet causes fat accumulation, abnormal blood lipids, and gut microbiota dysbiosis.It also increases the incidence of chronic diseases such as hyperlipidemia.Aimed to investigate the effects of inulin combined with Auricularia auricula polysaccharides(AAP) on serum indices, hepatic lipid deposition, and gut microbiota in high-fat diet-fed mice.The study first evaluated the hypolipidemic activity of inulin and AAP mixtures at different ratios (5∶0, 4∶1, 3∶2, 2∶3, 1∶4, 0∶5) using in vitro assays.Mice were divided into a normal control group fed a standard diet, a high-fat model group fed a high-fat diet, and intervention groups fed the high-fat diet supplemented with the different polysaccharide mixtures.After 8 weeks of intervention, the study examined the effects of the high-fat diet on serum parameters, liver tissue, and gut microbiota in the mice.Results showed that the inulin-AAP mixture at a 2∶3 ratio achieved the highest binding rates for both sodium glycocholate and sodium taurocholate.All polysaccharide mixtures significantly reduced body weight and liver index in the experimental mice.Serum levels of TC, TG, and LDL-C decreased markedly, while HDL-C levels increased significantly.Furthermore, the number and size of lipid droplets in the liver tissue were substantially reduced.The combined intervention demonstrated more pronounced effects than using either inulin or AAP alone.Intervention with the inulin-AAP mixture increased the relative abundance of short-chain fatty acid-producing bacteria.These included genera such as Lactobacillus, Odoribacter, Parabacteroides, and Bacteroides.The mixture also decreased the relative abundance of Desulfovibrio, Helicobacter, Ruminococcus torques, and Colidextribacter.This study indicated that inulin combined with AAP regulates blood lipids and improves gut microbiota in high-fat diet-fed mice.The findings offer a new perspective for developing strategies to prevent hyperlipidemia and create related functional products.

This study employed untargeted metabolomics to investigate the protective mechanisms of raspberry crude polysaccharides (RCP) against ultraviolet B (UVB)-induced skin photodamage.A UVB-induced skin photodamage model was established in BALB/c mice.Histopathological changes in skin tissues were assessed using hematoxylin-eosin staining.Superoxide dismutase (SOD) and catalase (CAT) activities in skin tissues were quantified via microplate assays, while IL-6, TNF-α, and matrix metalloproteinase-3 (MMP-3) levels in skin tissues were determined by enzyme-linked immunosorbent assay. Skin metabolic profiles were analyzed by untargeted metabolomics.Results demonstrated that RCP alleviated UVB-induced epidermal thickening, hyperkeratosis, fibrous tissue hyperplasia, and inflammatory cell infiltration.RCP intervention significantly enhanced SOD and CAT activities while reducing IL-6, TNF-α, and MMP-3 levels in UVB-damaged skin.Untargeted metabolomics identified 58 differentially expressed metabolites in skin tissues, with pathway enrichment analysis revealing alanine, aspartate, and glutamate metabolism as the most significantly enriched amino acid pathway.Correlation analysis indicated a strong positive association between alanine and SOD activity, whereas DL-asparagine, glutamate, L-glutamine, and N-acetyl-L-aspartate exhibited negative correlations with SOD.These findings suggest that RCP mitigates UVB-induced skin oxidative stress by modulating alanine, aspartate, and glutamate metabolism.

Atopic dermatitis (AD) is a type of allergic skin disorder with high occurrence frequency.In this study, multiple prebiotics with immunomodulatory properties, including fructooligosaccharides (FOS), galactooligosaccharides (GOS), xylooligosaccharides (XOS), and inulin were selected based on literature review, aiming to investigate alleviation effects of individual prebiotics and their mixture on AD symptoms.The results indicated that prebiotic intervention alleviated pathological symptoms of skin in AD mice, accompanied by reduced infiltration of allergy-associated cells, decreased levels of immunoglobulin E (IgE) in serum and inflammatory cytokines, i.e. IL-4, IL-5, IL-13, and thymic stromal lymphopoietin (TSLP) in skin tissue, along with increased levels of IFN-γ in skin tissue.Among all groups, the mixture of four prebiotics demonstrated more efficient alleviation compared to individual prebiotic components.Sequencing analysis on gut microbiota revealed that the prebiotic mixture significantly regulated community structure, increased α-diversity, markedly elevated the relative abundance of potential beneficial genera (e.g., Angelakisella and Ruminiclostridium 5), and enriched abundances of operational taxonomic units such as Erysipelotrichaceae bacterium NYU-BL-F16.Microbial interaction network and correlation analyses demonstrated that enriched gut bacteria in response to prebiotic mixture intervention were significantly associated with alterations in inflammatory-associated indexes.Collectively, the prebiotic mixture exhibited more efficient mitigation against AD, achieving synergistic effects, which would contribute to AD alleviation via routes of regulating gut microbiota and modulating immune aspects of host, and provide scientific basis for development of novel intervention strategy against AD.

Pediococcus acidilactici is extensively utilized in the food and feed industries due to its diverse origins and probiotic properties.In this study, we conducted whole-genome sequencing and assembly of nine P.acidilactici strains isolated from the feces of piglets.Additionally, we performed a comparative genomic analysis by integrating genomic data from 275 P.acidilactici strains available in the NCBI database.Our findings indicated that the pan-genome of these 284 P.acidilactici strains followed an open-state trend.Phylogenetic analysis and average nucleotide identity (ANI) clustering produced consistent results, classifying the strains into two major genetic clades.Notably, human- and animal-derived strains exhibited a relatively clustered distribution within the phylogenetic tree, whereas plant-derived strains were interspersed.Comparative genomic analysis revealed that human-derived P.acidilactici strains possessed significantly smaller genomes, lower GC content, and fewer coding sequences (CDSs) than their animal- and plant-derived counterparts (P<0.05).Furthermore, animal-derived strains exhibited significantly higher copy numbers of carbohydrate-active enzyme (CAZy) families, such as GH2 and CBM50, than human-derived strains (P<0.05).Functional annotation further demonstrated that genes associated with information storage and processing were significantly more abundant in animal-derived strains than in human-derived strains (P<0.000 1), whereas genes involved in cell growth and signal transduction displayed the opposite pattern (P<0.000 1).No significant differences (P>0.05) were observed between pig-derived strains and other animal-derived strains regarding fundamental genomic characteristics and Clusters of Orthologous Groups (COG) functional classifications.However, pig-derived strains exhibited significantly higher copy numbers of GT2, GT4, and GT26 family genes than other animal-derived strains (P<0.05), whereas CE10 and GH43 family genes were significantly less abundant (P>0.05).Additionally, 44.4% of animal-derived strains contained bacteriocin gene clusters, with a higher prevalence than those in human- or plant-derived strains.This study provides a comprehensive genomic characterization of P.acidilactici strains from diverse sources, offering valuable insights into their genetic diversity and evolutionary adaptations to distinct ecological niches.

Postbiotics are inactivated microorganisms or included their metabolites that benefit host health.Compared with probiotics, they have higher safety, stronger stability, and a broader range of action targets, thus showing significant advantages in alleviating inflammatory bowel disease.This study evaluated the ameliorative effect of the postbiotic from Bifidobacterium longum subsp. longum HSBL001 on dextran sulfate sodium -induced ulcerative colitis mouse model, and explored the potential mechanism of this effect via metagenomics and metabolomics.Results indicate that HSBL001 significantly alleviates colitis-related symptoms, including reducing the disease activity index, increasing colon length, improving histopathological damage, regulating inflammatory cytokine secretion (increasing IL-10 while decreasing IL-6 and TNF-α), and alleviating splenomegaly.Metagenomic analysis showed that HSBL001 significantly increased the abundance of beneficial bacteria such as Duncaniella dubosii, Faecalibacterium rodentium, and Bacteroides thetaiotaomicron, while reducing the abundance of bacteria like Mucispirillum schaedleri and Pumilibacter muris. Metabolomic analysis revealed that HSBL001 significantly upregulated 95 metabolites compared to the model group, including S-nitrosoglutathione, α-linolenic acid, and 7α-hydroxy-3-oxocholest-4-en-27-oic acid, while significantly downregulating 80 metabolites including 3-hydroxyisovaleric acid and N-Acetyl-D-glucosaminitol.Pathway enrichment analysis of these differential metabolites shows that the postbiotic alleviates colitis mainly by regulating pathways such as primary bile acid biosynthesis and α-linolenic acid metabolism.In conclusion, supplementation with the HSBL001 effectively alleviates ulcerative colitis symptoms in mice.Its potential mechanisms are closely linked to regulating gut microbiota composition, increasing the abundance of bacteria such as D.dubosii and F.rodentium, as well as modulating primary bile acid biosynthesis and α-linolenic acid metabolism.This study provides a new intervention method and research insights for alleviating colitis, and a theoretical basis for the industrial application of postbiotics.

Lactiplantibacillus plantarum exhibits extensive carbohydrate metabolic capabilities.This study compared the distribution of carbohydrate-active enzyme (CAZy) genes, differential carbohydrate utilization, and variations in free amino acid content during green pepper fermentation between tropical and nontropical strains.Key findings revealed that tropical strains possessed a significantly higher average number of glycosyltransferase (GT) family genes (310±13) compared to nontropical strains (296±5, P<0.05), with GT2 and GT4 families being particularly enriched.Tropical strains showed superior rhamnose metabolism[shorter generation time:(0.62±0.11) h vs.(1.35±0.27) h, P<0.05] but weaker utilization of sucrose[generation time:(1.43±0.06) h vs.(1.09±0.06) h) and fructose[(1.42±0.09) h vs.(1.03±0.09) h, P<0.01].No significant differences were observed for xylose, maltose, stachyose, or glucose (P>0.05).Fermented green peppers inoculated with tropical strains contained higher levels of arginine[(5.15±0.11) mg/100 g vs.(2.69±0.75) mg/100 g] and serine[(2.09±0.22) mg/100 g vs.(0.83±0.53) mg/100 g] compared to nontropical strains (P≤0.05).Notably, arginine content exceeded that of the commercial control[(2.10±0.36) mg/100 g, P≤0.001].Geographic origin drives adaptive divergence in CAZy genes (particularly GT families) of L.plantarum, providing a rationale for developing region-specific probiotics.

Astragalus polysaccharide (APS) exhibits multiple physiological activities, making its efficient development and utilization highly significant. This study investigated the cryoprotective effects of purified APS (composed of 64.38% glucose, 19.81% galactose, and 15.81% arabinose) in combination with other cryoprotectants on Lactobacillus acidophilus CICC 22162 during freeze-drying.Results showed that the APS-based cryoprotectant significantly improved bacterial survival to (85.02±1.25)%.Scanning electron microscopy revealed more uniform cellular morphology, compared with conventional cryoprotectants, the APS-based formulation also resulted in a 15.5% lower than conventional protectants, lactate dehydrogenase leakage decreased by 38.7%, viability reduction in lysozyme sensitivity tests was 20.6% lower, NaCl-induced membrane damage was reduced by 37.2%, and histone phosphorylation leakage decreased by 68%.These findings proved APS better maintains cell wall/membrane integrity, reduced intracellular content leakage, and enhanced resistance to environmental stresses.The formulation achieved 81.3% survival in simulated gastrointestinal digestion (33.9% improvement over conventional protectants) and maintained 9.18 lg CFU/mL viability after 120 days at 4 ℃.The APS-based cryoprotectant enables production of freeze-dried probiotics with high viability, excellent gastrointestinal tolerance, and superior stability, representing an innovative protection strategy with significant application value in functional foods and gut microbiota regulation.

Bacillus cereus is a common foodborne pathogen that can not only contaminate various foods and cause diseases, but is also hard to eliminate during production and processing, necessitating effective methods to inhibit it.This study aimed to investigate the biological characteristics of the antimicrobial peptide Temporin L and its antibacterial activity and mechanism against B.cereus.Firstly, the biological characteristics of Temporin L were predicted using online bioinformatics software.Then, the antibacterial activity and stability of B.cereus under different conditions were determined by the microbroth method.Finally, scanning electron microscope and molecular docking analysis revealed the mechanism of action against B.cereus.Results showed that Temporin L was a small molecule, positively charged, stable, and non-toxic hydrophobic polypeptide with extended chains.Temporin L did not have transmembrane regions or signal peptides, and 11 proteases could cleave it.In addition, Temporin L exhibited strong antibacterial activity against B.cereus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration of 8 μmol/L and 16 μmol/L, respectively.Temporin L maintained its antibacterial efficacy (MIC remained at 8 μmol/L) under varying environmental conditions (temperature, ultraviolet rays, pH, metal ions).Further analysis revealed that Temporin L could change the morphology of B.cereus.At the same time, Temporin L could produce good binding energy to DNA and phospholipase C through the formation of hydrogen bonds and hydrophobicity.In summary, Temporin L not only exhibits good biological properties, but also effectively inhibits the growth of B.cereus, and its excellent stability makes it expected to become a new type of food preservative.

Ferulic acid decarboxylase (FDC) can biocatalyze ferulic acid to produce 4-vinylguaiacol, which was widely used in food, medicine, cosmetics and other industries.To study the enzymatic properties and catalytic function of ferulic acid decarboxylase from non-Saccharomyces yeasts, ferulic acid decarboxylase XM from Wickerhamomyces anomalus was screened from the National Center for Biotechnology Information (NCBI) database to achieve heterologous expression in Pichia pastoris.Molecular docking of ferulic acid decarboxylase XM with four acids (caffeic, ferulic, p-coumaric, and sinapic acids) predicted five amino acid residues (tyrosine, phenylalanine, histidine, glutamine, and glutamate) that might change the function of ferulic acid decarboxylase XM.The results showed that the enzyme activity of the recombinant protein were (19.72±0.32) IU/mg and (136.39±2.94) IU/mg in shake flasks and in fermenters after 84 h of induction, respectively.The recombinant enzyme showed maximum activity at 40 ℃ and pH 6.0.The enzyme had broad substrate specificity and was able to efficiently decarboxylate four acids at a substrate concentration of 4 mmol/L.The K_m values of caffeic acid, ferulic acid, p-coumaric acid, and sinapic acid were (151.94±9.30), (133.70±5.62), (152.09±5.33), and (170.89±8.76) μmol/L, respectively, and the V_max values were (156.23±2.19), (158.16±1.52), (156.86±1.14) and (128.64±0.96) IU/mg, respectively.This study laid a foundation for further exploring the catalytic mechanism of ferulic acid decarboxylase XM.

High-temperature Daqu is a saccharifying, fermenting, and aroma-producing agent in the production of Jiangxiangxing Baijiu.Its rich aroma affects the quality of Baijiu, but the aroma-producing functional microorganisms and flavor characteristics are still unclear.This study focuses on the dominant filamentous fungi in high-temperature Daqu.Though high-throughput sequencing, cultivation and in situ simulated fermentation, the study systematically analyzed their taxonomic relationships and aroma-producing characteristics.The results showed that Thermoascus (average relative abundance of 39.07%), Aspergillus (17.03%), Thermomyces (9.70%), and Paecilomyces (5.84%) were the dominant filamentous fungi, and their cultivation and morphological characteristics were successfully described based on culturomics.Further studies had found significant differences in the tolerance of dominant filamentous fungi to temperature and pH, but could utilize multiple carbon sources.In situ solid-state fermentation indicated that Thermomyces lanuginosus and Thermoascus crustaceus performed well in pyrazines;Paecilomyces variotii was superior in aromatic compounds;Aspergillus oryzae was superior in furans and esters.This study provides an important theoretical basis for the development of functional microbial resources in high-temperature Daqu and the enhancement of microbial community functions.

This research centers on the spreading and stacking fermentation process of Jiangxiangxing Baijiu, with the aim of elucidating the distribution patterns of the microbial structure and identifying their sources.Stacked fermented grains, Daqu, and environmental samples from the fourth-round production were utilized as research materials.High-throughput sequencing, gas chromatography, and various data analysis methods were employed to conduct this study.Results demonstrated that dominant bacteria, including Bacillus, Kroppenstedtia, Thermoactinomyces, and Virgibacillus, maintained their dominance throughout both the spreading and stacking processes.These bacteria, which were crucial during the stacking fermentation stage, started to accumulate during the spreading process.Similarly, Pichia, the absolute dominant fungus that played a vital role in the stacking process, was also gathered during the spreading stage.Regarding flavor substances, the total content of flavor compounds increased significantly during the spreading process, particularly acidic substances.During the stacking fermentation, the contents of aldehydes and acids decreased, while the amount of alcohols increased.A significant correlation was observed between microorganisms and flavor substances.For instance, acetic acid was significantly associated with multiple microorganisms.In the environmental microbial community, bacteria and fungi exhibited distinct compositional characteristics, and some of them were closely related to the microorganisms in the fermented grains.The inter-group difference analysis indicated that the fermented grains during the stacking process had high metabolic activity in multiple pathways.Microbial traceability analysis revealed that in the early stage of spreading, the bacteria and fungi in the fermented grains were strongly influenced by tools.After adding Daqu, it became the primary source of microorganisms.During the stacking process, fungi mainly originated from tools and the ground, and the contribution from workers was minimal.This study has clearly defined the dynamic changes and sources of microorganisms during the spreading and stacking fermentation process of Jiangxiangxing Baijiu, thereby providing a solid theoretical foundation for optimizing ecological brewing.

This study employed high-throughput sequencing and conventional culture methods to systematically investigate the bacterial community structure and main lactic acid bacteria populations in medium-temperature Daqu (MTD) from Xiangyang, Hubei.In addition, the taste quality was evaluated using electronic tongue technology.Results revealed that at the genus level, the core dominant bacterial genera in MTD were Weissella (38.65%), Lactobacillus (22.67%), Staphylococcus (7.28%), Pediococcus (4.19%), and Leuconostoc (3.88%).Among these, lactic acid bacteria accounted for an average relative abundance of 69.39% across all samples, occupying an absolute dominant position.Results from traditional cultivation methods indicated that Weissella cibaria was the most abundant lactic acid bacterium in MTD from the Xiangyang region.Functional analysis of the microbiota revealed that bacteria in MTD played a crucial role in the utilization of carbohydrates and proteins.Notably, besides conventional functional brewing microbiota, bacteria potentially capable of producing unfavorable flavors, such as Streptomyces, were detected at notable proportions, indicating the need for enhanced control of such microorganisms during Daqu production.Regarding taste quality, electronic tongue analysis revealed that sourness, saltiness, umami, and fullness exhibited the highest response values among the MTD samples.The most pronounced variation between different Daqu blocks was observed in sourness attributes.These differences may be closely associated with the heterogeneity of microbial metabolic activities.This study enhances the understanding of the bacterial community structure of MTD in the Xiangyang region and its relationship with taste quality.It also provides certain theoretical support for regional distilleries to improve their Daqu production processes, offering certain guidance for the modernization of traditional brewing techniques.

Disclose of spoilage bacteria and pathogen composition is essential for performing and optimizing the salt-reduced soy sauce fermentation process.It is also meaningful for the selection of functional strains that inhibit spoilage bacteria during soy sauce fermentation.In this study, high-throughput sequencing technology was employed to investigate the succession of bacterial communities during soy sauce fermentation with salt concentrations of 100 g/L, 120 g/L, and 140 g/L.The results revealed that Enterobacter and Staphylococcus were the dominant spoilage bacteria in the salt-reduced fermentation system, and their abundances were 16.38% to 79.13% and 0.05% to 71.76%, respectively.The abundances of functional bacteria such as Pediococcus and Lactiplantibacillus were lower than that of these spoilage bacteria, ranging from 0% to 1.14% and 0.03% to 1.10%, respectively.Lactic acid bacteria including Pediococcus, Lactiplantibacillus plantarum, and Enterococcus faecium that effectively inhibit spoilage bacteria (Enterobacter cloacae, Enterobacter hormaechei, Enterobacter sakazakii, Staphylococcus saprophyticus, and Staphylococcus gallinarum) were isolated from the moromi.Among them, Pediococcus pentosaceus and Lactiplantibacillus plantarum exhibited similar antimicrobial capability, and their inhibitory activity against the spoilage bacteria was higher than those of Pediococcus acidilactici and Enterococcus faecium.Moreover, the results showed that P.pentosaceus WT6, an isolate from soy sauce moromi exhibited suitable properties for salt reduction soy sauce fermentation.The OD₆₀₀ of P.pentosaceus WT6 reached 2.53 after 24 h of cultivation at 20 ℃, it tolerated 140 g/L salt (with a survival rate of 104.7%), and this strain produced 33.58 g/L organic acids.These results provide good references for the use of lactic acid bacteria to achieve salt reduction in soy sauce fermentation.

To explore the influence of microwave puffing pretreatment on the umami and flavor enhancement of soy sauce brewed from soybeans, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) were used to analyze the non-volatile substances and volatile flavor substances in soy sauce brewed from soybeans with puffed and unpuffed pretreatment, respectively.LC-MS analysis revealed that compared with brewed soy sauce without puffed pretreatment, the proportion of peptide components with a molecular weight <500 Da in puffed soy sauce was significantly increased (P<0.05), among which the content of polypeptides containing fresh amino acids, such as glutamic acid, was significantly increased.The results of GC-MS indicated that compared with the brewed soy sauce without puffed pretreatment, the types and contents of flavor substances in the puffed soy sauce were significantly increased (P<0.05), especially the volatile components related to the umami and flavor enhancement.Among them, phenylacetaldehyde, benzaldehyde, 3,4-dimethylbenzaldehyde, 4-vinyl-2-methoxyphenol, 2,4-di-tert-butylphenol, and methyl 2-hydroxy-3-phenylpropionate were typical characteristic volatile flavor substances, which respectively endow soy sauce with the characteristics of nutty aroma, floral and fruity aroma, caramel aroma, and roasting aroma.The above results indicated that microwave puffing pretreatment increased the content of umami and flavor enhancing substances in soy sauce and improved its flavor characteristics.This research provides new ideas for the development of high-quality umami soy sauce and has significant application value for technological innovation in the condiment industry.

The traditional Xinjiang artisanal cheese is widely believed in folk medicine to possess probiotic properties, including gastrointestinal regulation and blood lipid-lowering effects.However, scientific evidence supporting these purported probiotic functionalities remains limited.This study employs metagenomic sequencing technology to conduct an in-depth analysis of microbial community diversity in traditional Xinjiang cheese collected from pastoralists in Ili.Through comprehensive annotation and analysis using KEGG, eggNOG, and CAZy databases, we systematically characterized metabolic pathways, functional genes involved in metabolism, and associated enzymes.Furthermore, we isolated and identified bacterial strains with cholesterol-degrading capabilities.This research aims to enhance the scientific understanding of Xinjiang cheese and provide a theoretical foundation for exploring its potential probiotic functions.Metagenomic analysis revealed distinct microbial profiles between the samples:in sample X1, the predominant fungal species was Kluyveromyces marxianus , while the bacterial community was dominated by Lactobacillus (particularly Lactobacillus delbrueckii) and Streptococcus species.Sample X2 exhibited a more diverse fungal composition featuring both K.marxianus and Saccharomyces cerevisiae as dominant species.The bacterial profile was characterized by Streptococcus species, with notable prevalence of Streptococcus thermophilus.The KEGG enrichment analysis demonstrated that both X1 and X2 samples were significantly enriched in four lipid metabolism pathways (including triglyceride metabolism), confirming the cholesterol-lowering potential of their microbial communities.These findings provide valuable microbial resources and a theoretical foundation for developing cholesterol-reducing functional products.Through systematic screening, we obtained 10 bacterial strains exhibiting robust cholesterol-degrading capacity (>20% degradation rate).Notably, the Enterococcus lactis strain XY2-4 demonstrated exceptional performance with 66.63% cholesterol degradation, significantly surpassing the average level of the screened isolates (P<0.05).Furthermore, this study successfully isolated a cholesterol-degrading S.cerevisiae strain exhibiting 44.83% degradation efficiency, revealing its potential application value in lipid metabolism modulation.

Previous studies have showed that daily intake of cheese was associated with the health benefits to the bone and muscle function.However, few studies have explored the generation of osteogenic and myogenic regulatory bioactive peptides and their roles in the function of cheese.CCFM1263 is a strain with excellent proteolytic activity, characterized by its unique cleavage sites on casein.In fermented milk, it produces a variety of bioactive peptides.Both the fermented milk and whey derived from CCFM1263 demonstrate specific beneficial effects on bone and muscle tissues.This study investigated the impact of adding Lactobacillus helveticus CCFM1263 to cheddar cheese on bioactive peptide production and functionality during ripening.We analyzed proteolysis levels, key bioactive peptides during ripening, and the promoting effects of cheese extracts on osteoblast and myoblast proliferation, and investigated its potential regulatory role in bone and muscle health.Results showed that CCFM1263 accelerated protein hydrolysis, boosted the formation of bioactive peptides FPP, RHPHPHLSF, and NIPPLTQTPVVVPPFLQPE, and elevated IPP and VPP levels during maturation.Moreover, CCFM1263 enhanced the ability of cheddar cheese to promote osteoblast and myoblast proliferation.Overall, CCFM1263 has the potential to reduce maturation time and enhance cheese functionality.

The Lacticaseibacillus rhamnosus and Pediococcus pentosaceus co-fermentation were used to prepare potato fermented juice and high-fiber powder in this study, and the metabolites and related metabolic pathways were analyzed using an ultra-high-performance liquid chromatography-quadrupole-time of flight mass spectrometry.Results showed that 1 593 and 1 344 metabolites were identified in potato juice and high-fiber powder fermented by lactic acid bacteria, respectively, and 18 and 19 key differential metabolites were further screened based on variable importance in projection (VIP) ≥1 and P<0.05, respectively.The results of KEGG pathway enrichment analysis showed that glycerophospholipid metabolism and arginine biosynthesis were significant enriched metabolic pathways in potato fermented juice and high-fiber powder, while nicotinate/nicotinamide metabolism and starch/sucrose metabolism were the differential metabolic pathways in the potato fermented juice and high-fiber powder, respectively.These metabolic pathways were closely related to the potato amino acids metabolism, biosynthesis of phosphatidylcholine, carbohydrate catabolism, and nicotinamide synthesis and metabolism.The above results could provide a reference and data support for the development of potato juice and high-fiber powder products based on lactic acid bacteria fermentation technology, and have important reference value for the research and development of functional foods.

The study examined the five probiotics strains (Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. Bulgaricus, and Streptococcus salivarius subsp. thermophilus) for their potential in blueberry juice fermentation.The aim was to identify the most suitable strains and assess their impact on mouse gut health by evaluating sensory quality, soluble solids, total acidity, pH, total sugars, total phenols, and total anthocyanins, as well as antioxidant ability and flavour.Results indicated that fermentation with probiotics improved various aspects of the blueberry juice.Among the probiotic strains, L. plantarum and L.acidophilus exhibited higher utilization of soluble sugars and stronger acid production capabilities, reaching 1.55 and 1.39 g/L, respectively.In terms of total phenols and antioxidant capacity, L.plantarum, L.casei, and L.delbrueckii subsp. bulgaricus all showed significant improvements, although there were no significant differences in total anthocyanins.A total of 35 species were detected by GC-IMS, among which, the L.plantarum fermentation group had a higher and more varied content of alcohols, aldehydes and ketones, which conferred fruity and floral aroma to the fermented blueberry juice.Regarding gut health, L.plantarum fermented blueberry juice could ameliorate minor damage to the liver, kidney, and small intestinal villi and their surrounding tissue cells in mice with intestinal disorders.The L.plantarum fermented blueberry juice could increase the abundance of beneficial butyric acid-producing genera, such as Treponema spp.in the phylum Bacillota, and inhibit the growth of pro-inflammatory flora, such as norank_f__Prevotellaceae and harmful bacteria, such as Thomasclavelia.In conclusion, L.plantarum-fermented blueberry juice showed potential for promoting gut health, offering valuable insight for the development of probiotic-fermented blueberry juice with gut health protection.

To enhance the utilization of soybean byproduct soy whey, this study developed a co-fermented drink using soy whey supplemented with passion fruit and lactic acid bacteria (LAB) to investigate the dynamic changes in physicochemical indices, viable cell count, nutritional components, antioxidant activity, and flavor compounds during fermentation (0, 6, 12, 18, 24 h).Results showed that the LAB-passion fruit soy whey drink reached the highest total viable count and antioxidant activity at 18 h.Parameters including pH, total acidity, soluble solids, total phenolics, and total flavonoids increased significantly and then stabilized.Compared to pure soy whey fermentation, the conversion rate of isoflavone glucosides to aglycones was slower in the co-fermented beverage.A total of 84 volatile flavor compounds were detected across five fermentation stages, dominated by esters and alcohols, with the highest total content (1 333.30 μg/kg) at 18 h.Partial least squares discriminant analysis and odor activity value analyses identified linalool, hexyl acetate, myrcene, and acetic acid as key marker compounds defining the aroma profile.This study provides theoretical and practical references for soy whey valorization.

To enhance the utilization of apple peel by-products, this study used Lactiplantibacillus plantarum to ferment apple peel and treated it with two methods, including vacuum freeze-drying and hot air drying, then the properties and in vitro digestion characteristics of the powders were analyzed.Results showed that the color of vacuum freeze-drying apple peel powders was bright and light (with high L^*and a^*values), close to the color of the original apple peel.The total phenolic content of vacuum freeze-drying apple peel powder was 9.79 mg/g, compared to hot air drying, vacuum freeze-drying also exhibited a lower packing density and packing density, a larger angle of repose and sliding, and a looser powder structure, besides, the total antioxidant capacity of freeze-dried powder was 1.83 times that of hot-air-dried samples.Fermented apple peel has a low packing density, high brightness, and a light-yellow color.In vitro digestion simulations (oral, gastric, and intestinal phases), the total phenols, soluble dietary fiber, and three antioxidant capacities of fermented apple peel powder were 1.38-1.43, 1.8-4.9, and 1.12-1.33 times higher than those of unfermented apple peel powder, respectively, exhibited a strong nutritional characteristics and biological activity.This study provides a new direction for the development and utilization of apple by-products, also provides a theoretical basis for the deep processing of apple peels.

Traditional rose jam is not accepted by the public because of its high sugar, which can inhibit harmful bacteria, and the hypoglycemic fermentation leads to the deterioration of the quality of rose jam.To improve both the security and the flavor of fermented rose jam, five different sucrose-xylitol ratios of rose jams at the end of fermentation were subjected to study, it was found that fermented rose jam with moderate sugar reduction (50%) had higher sensory quality (color and odor) and physicochemical properties (sugar content, acidity, functional active substances, and antioxidant capacity).Meanwhile, after analyzing the flavors of low-sugar rose jam, it was found that the percentage of aldehydes, alcohols, acids, and esters in rose jam increased, the types of volatile flavors decreased, but the content increased, and the distribution of characteristic flavors was more concentrated after low-sugar fermentation.Zygosaccharomyces sp., Achromobacter spanius, Pseudomonas aeruginosa, Pedobacter nutrimenti, and Leifsonia shinshuensis significantly contributed to the increase of 2-methyl-1-propyl acetate, isoamyl acetate, methyl acetate, ethyl propanoate, acetic acid-D, acetic acid ethyl ester, 2-methyl-1-propanol, and 3-methylbutan-1-ol-D.This study might provide a theoretical basis for the production of rose jam by reduced sugar fermentation.

Iron deficiency is one of the common nutritional disorders worldwide, and peptide iron chelates are considered as an ideal source of iron supplementation due to their high bioavailability.In this study, peanut peptides were obtained from peanut meal by fermentation of Monascus anka with Bacillus subtilis, combined with ferrous ions to prepare peptide-iron chelates, and structurally characterized the peptide-iron chelates to analyze their stability under different pH and temperature conditions.Results showed that the peanut peptides generated after 72 h of fermentation had molecular weights mainly distributed below 1 kDa and had higher iron chelation rates.Under the optimal chelation conditions, the iron chelation rate reached (61.45±0.28)%.The results of Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectroscopy showed that the structure of the peptide-iron chelates changed, and that the ferrous ions were mainly combined with the carboxyl and amino groups in the peptides to form a kind of peptide-iron chelate distinguished from the simple physical mixtures.Among the amino acid composition of the peptides, Asp and Glu contributed most significantly to iron chelation.The peptide-iron chelate had a larger particle size[(497.22±5.95) nm] and a higher zeta potential[(-9.20±0.36) mV] compared to the peanut peptide.This was closely related to the changes in its secondary structure and apparent morphology.In addition, the peptide-iron chelate showed good pH and thermal stability.The above results provide a theoretical basis for the development of novel peptide iron supplements using fermentation technology.

The antioxidant capacity and inhibition effect of acetylcholinesterase activity of γ-aminobutyric acid (GABA) from germinated brown rice in vitro and its molecular mechanism were investigated.The antioxidant capacity of GABA from germinated brown rice was evaluated by scavenging tests of DPPH free radical, ABTS cation free radical and hydroxyl free radical.Half inhibitory concentration (IC₅₀) of GABA were 0.082, 0.075 and 0.216 mg/mL, respectively, indicating that GABA has good antioxidant capacity.The inhibitory effect of GABA on acetylcholinesterase (AChE) in germinated brown rice was investigated by enzyme inhibition assay.The inhibition rate of GABA on AChE was 59.77%, and its IC₅₀ value was 2.49 mg/mL, which indicated that GABA had a good inhibitory effect, and its inhibition type was reversible non-competitive inhibition.The dynamic behavior of the molecular system was investigated by molecular docking and molecular dynamics simulation.The results showed that GABA mainly combined with the amino acid residues such as Tyr130 and Gly117 of AChE through hydrogen bonding and hydrophobic interaction, with a binding free energy of-5.37 kcal/mol, and the binding state was relatively stable.The mechanism of GABA inhibition of AChE in sprouted brown rice was revealed at the molecular level.This study provides a basis for the application of germinated brown rice rich in GABA in the development of anti-aging functional foods.

Propolis extract (PE) is rich in various bioactive substances, yet its application is limited due to low solubility and instability.To overcome these limitations, this study utilized the interaction between carboxymethyl chitosan (CMCS) and β-cyclodextrin (β-CD) to co-load PE.The research found that by adjusting the addition sequence, the ratio of CMCS to β-CD, and the amount of PE added (0.5%), the aggregation and precipitation of PE could be effectively controlled, thereby enhancing its stability.Additionally, the results from electron microscopy, particle size analysis (4 778.3 nm), zeta potential measurements (-30 mV), and multidimensional physicochemical characterizations demonstrate that PE is primarily encapsulated within the CMCS/β-CD co-loading system through hydrogen bonding, electrostatic interactions, and hydrophobic interactions.This study provides a theoretical reference for constructing the CMCS/β-CD-PE co-loading system encapsulating PE, broadening the application of PE in the food industry.

The complex system formed by proteins and polysaccharides has stronger functional properties than single protein and polysaccharide fractions, and the Idesia polycarpa Maxim.cake meal(IPCM) is rich in proteins and polysaccharides.In this study, the effect of 1%-5% (mass fraction) cellulase addition on the physicochemical and functional properties of protein-polysaccharide complexes of alkaline solubilization extracted from IPCM.Results showed that the protein and polysaccharide contents of the complexes increased significantly (P<0.05) with the increase of cellulase addition from 0% to 5%, but there was no significant difference in the total phenol and flavonoid contents (P>0.05).It was also found that the solubility, water-holding capacity, oil-holding capacity, emulsifying activity, and emulsifying stability of the complexes were improved after cellulase treatment compared with the control group, showing a trend of increasing and then decreasing, and reached the highest level at 3% addition, which was 36.22%, 74.70%, 53.91%, 7.32% and 58.00% higher than that of control group, respectively (P<0.05).This study confirmed that protein-polysaccharide complex systems with good physicochemical and functional properties could be obtained by regulating the addition of cellulase.It provides technical support for the comprehensive resource processing and utilization IPCM.

The objective of this study is to compare and analyze the effectual differences of methods for extracting polyphenols from sweet potato pericarp based on non-targeted metabolomics techniques.In the study, polyphenols were extracted from sweet potato pericarp by water extraction, ultrasound-assisted alcohol extraction, and vitamin C-assisted alcohol extraction.After LC-MS detection, principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and other multivariate statistical analyses were performed to screen characteristic metabolites and analyze the effects of different methods on components.Results showed that a total of 401 phenolic compounds were identified, and PCA suggested stably aggregated samples of the water extraction group, as well as a great heterogeneity between the ultrasound-assisted alcohol extraction group and the vitamin C-assisted alcohol extraction group.By OPLS-DA verification, the inter-group differences were significant.There were 2 263, 2 292, and 489 metabolites with differences between ultrasound-assisted alcohol extraction and water extraction, ultrasound-assisted alcohol extraction, and vitamin C-assisted alcohol extraction, together with water extraction and vitamin C-assisted alcohol extraction, respectively, and metabolites were mainly enriched in lipid, amino acid, and carbohydrate pathways.The three methods presented different mechanisms of action.Ultrasound-assisted alcohol extraction had better effects in extracting ferulic acid and flavonoids, and vitamin C-assisted alcohol extraction could balance component diversity and stability, laying a foundation for the high-value utilization of sweet potato skin pericarp.

This study pioneered the application of steam-assisted roasting, a novel cooking method, to oysters.Under a roasting temperature of 200 ℃, oysters were cooked using no steam (NS), 25% low steam (LS), and 50% high steam (HS) until their core temperature reached 65, 70, or 75 ℃, respectively.Physicochemical properties, sensory attributes, and flavor profiles were analyzed to elucidate the effects of steam-assisted roasting.Results showed that cooking time decreased with increasing steam levels.Sensory evaluation indicated that higher steam levels improved oyster morphology and glossiness, with LS-75 ℃, HS-70 ℃, and NS-75 ℃ receiving higher preference scores.Compared to NS, LS significantly increased cooking loss at all core temperatures (P<0.05), while HS increased loss at 65 and 75 ℃.Both steam treatments (LS and HS) at 70 and 75 ℃significantly reduced water-soluble and salt-soluble protein contents while elevating carbonyl levels (P<0.05).TBARS values increased with steam levels at all core temperatures (P<0.05).Steam-assisted roasting reduced Schiff base and fluorescent AGEs formation at 65 and 70 ℃.Volatile analysis identified 40 compounds, with HS-70 ℃ and LS-75 ℃ exhibiting richer flavor profiles.This study demonstrates that steam-assisted roasting promotes protein and lipid oxidation in oysters while suppressing Maillard reaction byproducts and enhancing volatile flavor diversity under identical core temperatures.These findings provide insights for novel thermal processing technologies in aquatic products.

This study investigated the effects of buckwheat flour addition (0%-25%) on the quality (cooking and textural characteristics), structural characteristic of components (protein and starch), and in vitro digestibility characteristics of handmade hollow dried noodles.The relationships between noodle quality and structural characteristic of components were established, and key components determining quality were identified.Results showed that buckwheat flour improved dough dynamic rheological properties through synergistic interactions of proteins and dietary fibers.However, excessive addition of buckwheat flour (25%) diluted gluten proteins and disrupted the gluten network, which significantly deteriorated the noodle’s quality.X-ray diffraction and infrared spectroscopy revealed that 25% buckwheat flour addition markedly reduced structural orderliness, evidenced by a significant decrease in starch crystallinity and in the content of ordered protein secondary structures (α-helix and β-sheet).Furthermore, scanning electron microscopy and in vitro digestion analyses demonstrated that increasing the buckwheat flour proportion to 15% enhanced starch aggregation and the formation of resistant starch.These changes led to a significant reduction in the starch digestion rate and the estimated glycemic index.This study concludes that handmade hollow dried noodles achieve an optimal balance of quality and nutritional characteristics when the buckwheat flour addition level is between 15% and 20%.

To explore the effect of high-energy electron beam irradiation on the quality of Broussonetia papyrifera leaves, this study analyzed the impacts of various doses (0, 8, 10, 15, 20 kGy) of irradiation on microbial quantity, nutritional quality, active components, tannin content and antioxidant activities of B.papyrifera leaves.The results indicated that, compared to the non-irradiated group (0 kGy), a dose of 8 kGy inactivated all microorganisms except aerobic bacteria (<2 lg CFU/g fresh weight), thereby meeting conventional sterilization requirements.A dose of 15 kGy achieved complete sterilization.Doses ranging from 8 to 20 kGy had no significant effect on the contents of dry matter, crude protein, soluble carbohydrates, neutral detergent fiber, and acidic detergent fiber in the leaves (P>0.05).In contrast, the contents of all amino acids except glycine changed significantly (P<0.05).As the irradiation dose increased, total phenol content rose continuously, whereas total flavonoids decreased significantly.Tannin content exhibited a trend of first reducing and then increasing, reaching its lowest point at 15 kGy.ABTS cation and DPPH radical scavenging capacities decreased with increasing doses.Hydroxyl radical scavenging capacity showed a trend of first decreasing and then increasing.Overall, total antioxidant capacity declined.In conclusion, an 8 kGy dose is suitable for B.papyrifera leaves that need to retain the integrity of amino acids, balancing microbial control and nutritional protection.A dose of 15 kGy meets stringent sterilization requirements and achieves partial tannin degradation;however, it significantly reduces the antioxidant activity of B.papyrifera.This research provides a scientific basis for the irradiation processing of B.papyrifera leaves by elucidating the relationship between irradiation dose and quality indicators.

To effectively improve the drying quality of chili peppers while reducing the drying energy consumption, based on the novel quasi two-stage frequency conversion heat pump drying system, this paper experimentally investigated the impact of the circulating air volume as a key factor on both the drying quality indices of chili peppers and the influence of the system performance indices.Results showed that under the condition of drying temperature (60 ℃) and loading capacity (8.0 kg), with the increase of the circulating air volume from 360 to 720 m³/h, the water evaporation rate of chili pepper was accelerated, the average drying rate was on an increasing trend, and the drying time was shortened.The system energy efficiency ratio (COP_sys) showed a general trend of increasing and then fluctuating downward, the specific moisture extraction rate (SMER) increased and then decreased, and the color difference value of dried chili pepper first decreased and then increased.When the circulating air volume was 720 m³/h, the drying rate reached the maximum value of 0.45 g/(g·h).When the circulating air volume was 540 m³/h, the COP_sys, the average SMER reached the maximum value of 5.27 and 0.33 kg/(kW·h), respectively.In addition, the optimal color of chili pepper was achieved at this air volume.Therefore, considering energy consumption, drying efficiency and quality,540 m³/h was finally selected as the optimal circulating air volume of pepper heat pump drying.

In order to explore the effects of different concentrations of ozone treatment on the storage quality and ethylene synthesis of postharvest prunes, this experiment selected (0, 64.2, 96.3, 128.4 mg/m³) concentrations of ozone, and treated prunes every 15 days.The fruits were stored at near-ice temperature (-1--1.5 ℃) and relative humidity (80%-90%), and the storage quality and ethylene synthesis metabolism indexes of prunes were determined.The results showed that different concentrations of ozone treatment could inhibit the respiration rate of prunes, delay the decrease of fruit hardness and weight loss rate, and maintain the content of total soluble solids, titratable acidity and ascorbic acid.Among them, 96.3 mg/m³ ozone treatment had the best preservation effect on prunes.Further studies showed that 96.3 mg/m³ ozone group could inhibit the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase the key rate-limiting enzymes in ethylene synthesis, and reduce the conversion of Methionine and S-adenosyl methionine, the precursors of ethylene synthesis.It reduced the production of ACC and ethylene, and enhanced the antioxidant capacity of fruits.The results showed that ozone treatment could prolong the storage period of prunes by maintaining the storage quality of prune and inhibiting the synthesis of endogenous.

This study aimed to elucidate the mechanism underlying the effect of tannin structure evolution during red wine production on astringency perception.Using ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry and quantitative descriptive analysis, we systematically investigated the untargeted metabolome of tannins and the evolution of astringency intensity across 12 key time points during Cabernet Sauvignon red wine production.Molecular docking was employed to investigate the molecular mechanism of tannin-α-amylase interaction, using α-amylase as a model salivary protein.Results showed that both total phenolic content and astringency intensity significantly increased during the fermentation stage and subsequently stabilized during aging.Tannin composition analysis revealed a decreasing proportion of catechin-type tannins throughout winemaking.Gallocatechin-type and catechin gallate-type tannins initially increased during fermentation (peaking at 19% and 14%, respectively) before decreasing and stabilizing during the aging stage.The average degree of polymerization significantly increased from 1.62 to 2.38 during alcoholic fermentation and remained stable during aging.Untargeted metabolomics revealed distinct accumulation patterns:most catechin-type tannins (e.g., DP1-1, DP2-1) peaked at the end of fermentation and stabilized during aging;most gallocatechin-type tannins (e.g., DP2+1P-2, DP3+1P-1) continuously accumulated, reaching peak levels after 12 months of aging;while most catechin gallate-type tannins (e.g., DP1+1G-1, DP2+1G-1) peaked during fermentation and decreased during aging.Molecular docking results indicated that tannin-α-amylase interactions were primarily driven by hydrogen bonds and hydrophobic forces.Binding strength of catechin-type tannins increased with increasing DP.For gallocatechin-type tannins, binding strength slightly decreased as the proportion of (epi)catechin units increased.Binding strength of catechin gallate-type tannins significantly increased with increasing esterification degree, showing high consistency with the observed changes in astringency intensity.These findings provide a theoretical basis for understanding how the complex evolution of tannin structure influences changes in astringency perception during red wine production.

With the consumer’s pursuit of food nutrition, there are a variety of functional eggs on the market to meet the needs of consumers.The purpose of this study was to evaluate the quality of Phaffia rhodozyma-derived astaxanthin eggs by comparing the differences in nutrients and functional properties of antioxidant, anti-inflammatory and lipid-lowering.The results showed that the astaxanthin eggs from P.rhodozyma contained (60.5±1.48) μg/g astaxanthin, (12.96±0.38) g/100 g protein, DHA accounted for 0.62%, EPA accounted for 0.18%, which were higher than those of astaxanthin eggs from Haematococcus pluvialis.The ratio of EAAs/TAAs JX was 39.1%, which was the same as that of astaxanthin eggs from H.pluvialis.The activity of SOD, the activity of total antioxidant capacity and glutathione peroxidase were higher than those of ordinary eggs.The lowest MDA value of was 457.62 nmol/L.The addition of astaxanthin could make the antioxidant capacity better than other eggs.The astaxanthin eggs from P.rhodozyma could reduce the secretion of interleukin-6, interleukin-10, tumor necrosis factor α and NO, and the inhibition rate was 1.61%.It had anti-inflammatory and fat reducing activity, while the content of lipid droplets decreased.The astaxanthin egg derived from P.rhodozyma is a high-quality functional egg, which can provide better nutritional value.

Whole grains are an important source of dietary polyphenols, which are rich in polyphenolic compounds that contribute to blood glucose and cholesterol control and are important for the prevention of diabetes and cardiovascular disease.However, their bioaccessibility is limited by complex matrix structures (e.g., cell wall-bound state, covalently bound state) and low release rates in the gastrointestinal environment.In recent years, multi-omics techniques have provided new tools to resolve the molecular mechanisms of microbial fermentation regulating polyphenol transformation.Studies have shown that fermentation can effectively convert bound polyphenols into free phenols that are more readily absorbed by the human body, thus enhancing the bioaccessibility of polyphenols, in which multi-omics technologies (macrogenomics, transcriptomics, metabolomics, and macroproteomics) provide new perspectives for analysing the pathways of polyphenol biotransformation.This paper reviews the metabolic transformation process of polyphenol components in fermented whole grains and how to improve the bioaccessibility of polyphenols, with the aim of providing a theoretical basis for the development and utilisation of fermented grain products that are beneficial to human health, and to further enhance the nutritional value and health benefits of whole grain products.

Foodborne peptides are small, bioactive molecules derived from proteins through processes such as enzymatic hydrolysis and fermentation.These peptides exhibit a range of biological activities, including blood pressure reduction, antioxidant effects, and immune regulation.Their sources, preparation methods, and key functions have attracted growing research interest.The biological activities of these peptides are influenced by amino acid sequences and structural characteristics.Recent advancements in enhancing their bioavailability focus on improving digestive stability and transmembrane absorption efficiency.Future research should prioritize efficient preparation methods, mechanisms of action, and safety assessments.Integrating multi-omics approaches with both in vivo and in vitro functional validations is expected to elucidate structure-function relationships and promote the application of foodborne peptides in functional foods and medical fields.

Pyranoanthocyanins are a new class of anthocyanin derivatives discovered in aged red wine, characterized by high stability and the ability to influence the quality and color of red wine to a certain extent.Additionally, previous studies have shown that pyranoanthocyanins can enhance anthocyanin stability and exhibit significant advantages in anti-cancer, anti-inflammatory, and antioxidant properties.Consequently, this article focuses on exploring the structure, color characteristics, stability, biological activity, and application of pyranoanthocyanins.The aim is to provide guidance for the development, utilization, and directed synthesis of pyranoanthocyanins.

Meat products play an important component of dietary nutrition, whose composition and quality changes directly affect food quality and human health.Machine learning utilizes computers to establish analytical models, taking a large amount of collected information as input data and the expected result information as output data and building their connections to achieve efficient and rapid result prediction.The quality detection of meat products based on machine learning is more efficient, accurate and convenient than traditional methods.The paper focuses on the typical applications of machine learning in the variation of substance content, identification of adulterated ingredients, microbial detection, and prediction of physical properties of meat products.It highlights the advantages of machine learning in quality detection of meat products, summarizes the current application trends and puts forward the shortcomings and challenges of the existing technologies;and the outlook of the quality control and monitoring of meat products is carried out in combination with the application of machine learning and other technologies in the digital background.

The freezing and thawing processes both have significant impacts on the meat quality.The formed ice crystals during the freezing process squeeze the tissue cells and myofibrillar protein, leading to the problems such as weakened water-holding capacity and deteriorated protein gel in the meat after thawing.Consequently, the thawing method has a crucial influence on the final quality of frozen meat.This review describes the classification, advantages and disadvantages, principles, and influencing factors of traditional thawing methods (air and water thawing) and novel thawing methods (high pressure, vacuum, microwave, radio frequency, far-infrared, ohmic heating, magnetic field, and ultrasonic thawing).It also summarizes the effects of thawing and repeated freezing-thawing on the quality changes of meat, and envisions the future research directions for frozen meat, providing a theoretical basis for studying the effects of thawing on the quality of frozen meat.

The quality and safety of grain and oil products are of paramount importance.Traditional detection methods, characterized by significant sample destruction and low efficiency, are difficult to meet the demands for rapid, non-destructive, and online detection in the modern grain and oil industry.This article reviews the relevant techniques and methods of domestic and international research on non-destructive testing of grain and oil.It discusses the applicable scope, advantages, and disadvantages of each techniques focusing on critical quality and safety indicators.Furthermore, the review provides an outlook on the future development trends of grain and oil detection, characterized by precise, efficient, and intelligence, as well as directions such as multi-data fusion and integration with artificial intelligence, serving as a reference for related research in the grain and oil industry.