The methylotrophic yeast Komagataella phaffii is a eukaryotic microorganism capable of utilizing methanol as sole carbon source, having been widely employed for protein and metabolite production.However, its endogenous methanol utilization efficiency requires further improvement.This study overexpressed encoding genes of key enzymes in the non-oxidative branch of the pentose phosphate pathway (PPP), including transketolase (tkt), ribulose-5-phosphate-3-epimerase (rpe), and fructose-1,6-bisphosphatase (fba), to enhance methanol assimilation.Results showed that tkt-GS115 exhibited a 1.7% increase in OD₆₀₀, with a maximum specific growth rate (μ) of 0.23 h^-1.Compared to the control strain ΔFLDH, fba-ΔFLDH entered the growth phase 18 h earlier, achieving a similar μ of 0.23 h^-1.Notably, rpe-ΔFDH and fba-ΔFDH rescued the growth defect of the parental strain ΔFDH in methanol minimal medium.Specifically, rpe-ΔFDH displayed significant growth potential, reaching a maximum OD₆₀₀of 6.97, while fba-ΔFDH achieved a remarkably high μ of 0.36 h^-1.Methanol utilization efficiency varied among the recombinant strains, including tkt-GS115, tkt-ΔFLDH, and fba-ΔFLDH showed improvements of 0.017, 0.007, and 0.034, respectively.This study demonstrates that reinforcing three key genes in the PPP non-oxidative branch effectively enhances methanol utilization efficiency in K.phaffii recombinant strains.

D-allulose, an important rare sugar, serves as a low-calorie sweetener with the ability to regulate lipid metabolism and blood glucose balance.In Bacillus subtilis, a biosynthetic pathway from glycerol to D-allulose has been successfully constructed through heterologous expression of alditol oxidase (AldO), L-fuculose-1-phosphate aldolase (FucA), and fructose-1-phosphatase (YqaB).After optimizing the promoter of FucA, the ratio of mixed whole-cell was optimized.Then, to simplify the mixed whole-cell conversion system, a whole-cell conversion system using a single strain was constructed.Furthermore, the whole-cell conversion conditions, including temperature, pH, whole-cell concentration, and glycerol concentration, were investigated.The optimal conditions for whole-cell conversion were 30 ℃, pH 6.5, whole-cell concentration 150 g/L, and glycerol concentration 50 g/L.Under optimized conditions, the production of D-allulose was achieved through glycerol feeding strategy, with the highest yield reaching 5.25 g/L, representing a 26.5% increase compared to the control group.This study presents a food-grade method for synthesizing D-allulose from glycerol.

This study explored the impact of germination time on the primary components and enzyme activities of wheat malt, as well as the aroma and volatile compounds both before and after roasting.The findings indicated that amino nitrogen, reducing sugars, and the activities of amylase and protease in both red and white wheat increased initially and then decreased during the germination process, peaking on the fifth day.A significant positive correlation was observed between amylose content and protease activity.Sensory analysis demonstrated that the aroma of pre-roasted malt varied with the length of germination, specifically, sour notes intensified while malty and herbal aromas reached their peak before subsequently declining.Following roasting, the sour aroma diminished, while aromas of caramel, nutty, bakery, and potato became more pronounced, particularly after five days of germination.Utilizing headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and the orthogonal partial least squares-discriminant analysis (OPLS-DA), significant changes were identified in 37 out of 63 aroma components, with 35 exhibiting variable importance in the projection (VIP) values greater than 1.Notably, key compounds contributing to the caramel flavor, such as maltol and furanone, were most prominent on the fifth day.This research provides valuable insights for optimizing the preparation process of crystalline wheat malt, thereby enhancing its sensory attributes in brewing.

In this study, bovine hide collagen antifreeze peptides were employed as a protective agent to investigate their impact on the moisture state, freezing characteristics, tissue structure, and edible quality of beef patties during repeated freeze-thaw cycles.The results showed that collagen antifreeze peptides lowered the freezing point and crystallization enthalpy of beef patties, promoting the formation of finer and more uniform ice crystals during freezing.They also inhibited ice crystal growth and recrystallization during repeated freeze-thaw cycles, thereby minimizing tissue damage.Additionally, they prevented the conversion of immobilized water to free water and reduced beef patties’ dehydration, significantly enhancing water-holding capacity (P<0.05).Moreover, the peptides delayed the decline in hardness, elasticity, and resilience (P<0.05), preserving the beef patties' desirable texture.They also postponed protein and lipid oxidation, significantly reducing the accumulation of amines, hydroperoxides, and malondialdehyde (P<0.05) and delaying spoilage and color deterioration.In conclusion, bovine hide collagen antifreeze peptides effectively maintain the quality of beef patties during repeated freeze-thaw cycles.This research provides a valuable theoretical basis for the development of high-quality frozen meat products.

Carminic acid, an aromatic polyketide compound, is a widely used natural red colorant.Traditionally, carminic acid is extracted from cochineal insects, but the extraction process is labor-intensive and inefficient, leading to insufficient production to meet the growing market demand.In recent years, biosynthetic production of carminic acid has attracted significant attention.In this study, Yarrowia lipolytica was used as a host strain to achieve the de novo synthesis of carminic acid through the heterologous expression and screening of key pathway genes, resulting in a production titer of 0.7 mg/L.Since carminic acid biosynthesis requires two critical precursors, malonyl-CoA and acetyl-CoA, efforts were first made to enhance malonyl-CoA supply by screening ACC1 mutants and introducing a non-native malonyl-CoA biosynthetic pathway (NCM pathway), which increased the carminic acid titer to 1.2 mg/L.Subsequently, acetyl-CoA supply was strengthened by regulating lipid metabolism, further boosting the titer to 1.5 mg/L.Additionally, by improving substrate utilization efficiency and relocating the carminic acid biosynthetic pathway to peroxisomes, the titer reached 1.9 mg/L.Finally, through fed-batch fermentation in a 5 L bioreactor, the production of carminic acid was scaled up to 9.6 mg/L (6.3×10^-3mg/g).This study provides a reference for the biosynthesis of carminic acid.

This study investigated the effects of the interfacial adsorption sequence and concentration of micro-fluidized high-pressure (DHPM)-transglutaminase (TG) co-treated modified whey protein concentrate (DHPM-TG-WPC) and chitosan oligosaccharide (COS) on the thermal stability and docosahexaenoic acid (DHA) sustained-release protection of algae oil multilayer emulsions.Results demonstrated that the “DHPM-TG-WPC-low methoxyl pectin-COS” sequence formed a stable interfacial layer through electrostatic interactions and covalent cross-linking, significantly enhancing thermal stability.In contrast, the “DHPM-TG-WPC-COS-LMP” sequence led to droplet aggregation and structural disruption due to interfacial instability.COS concentration markedly influenced emulsion performance, 5 g/L COS strengthened the interfacial layer, reduced droplet aggregation, and improved stability, whereas 10 g/L COS caused flocculation and stability degradation due to uneven adsorption.In simulated digestion, 5 g/L COS delayed DHA hydrolysis by reducing lipase-oil droplet contact, while 10 g/L COS was prone to detachment in alkaline intestinal fluid, destabilizing the interfacial layer and accelerating DHA release.This study elucidated the regulatory mechanisms of COS interfacial adsorption sequence and concentration on multilayer emulsion stability and DHA sustained release, providing a theoretical basis for the optimized design of DHA-functional emulsions.

Tyrosine is the main component of white spots in broad bean paste and soybean paste.Reducing the tyrosine content in mash can significantly reduce the probability of white spot formation.This study aimed to obtain microbial strains with strong tyrosine conversion ability and to apply in broad bean paste fermentation.Four microbial strains with potential tyrosine conversion ability were screened from broad bean paste mash and Baijiu mash and their salinity tolerance ability was tested.Bacillus subtilis R1 with relatively good salt tolerance was used as starting strain.Atmospheric pressure room temperature plasma technique was used for mutagenesis.After two-round screening, four mutant strains with enhanced tyrosine conversion ability were obtained, among which the tyrosine conversion rate of strain number R1-14 reached 33.0% under 8 g/L salinity.By microbial pass-on assay, B.subtilis R1-14 strain showed good genetic stability.Through quantitative real-time PCR (qRT-PCR) analysis, the conversion of tyrosine by B.subtilis R1-14 was achieved through both aspartate aminotransferase (AST) and polyphenol oxidase (PPO), which AST enzyme played more important role.Finally, B.subtilis R1-14 strain was applied in broad bean paste fermentation.Results showed that the application of mutant strain R1-14 could significantly reduce the tyrosine concentration in mash by 45.7%, which was better than starting strain.The above results showed that the mutant B.subtilis R1-14 strain had a good tyrosine conversion rate and could significantly reduce the tyrosine content in broad bean paste, which had potential application value for preventing the occurrence of white spots.

Pomace is the main by-product of fruit processing.It contains a large amount of pectin, which is an anti-nutritional factor that hinders digestion and reduces the bioavailability of the major nutrients.Fermenting pomace with pectinase producing yeast can increase its nutritional and functional value.Yeast strains were isolated from tomato pomace, and the growth ability of these yeasts in a medium with pectin as the sole carbon source were investigated.A yeast with high pectinase producing activity and probiotic potential was selected, and identified as Torulaspora delbrueckii.The pectinase activity of the strain was 27.21 U/mL, and it had a survival rate of 86% at pH 2.5 and 83% in 3 g/L bile salt.Its hydrophobicity was 43.25%, and its self-aggregation ability was 61.18%.Its co-aggregation abilities with Escherichia coli and Staphylococcus aureus were 41.18% and 58.52%, respectively, and did not show the hemolytic activity.After fermented with T.delbrueckii A9, the pectin content of pomace decreased by 62.82%, the reducing sugar content increased by 156.72%.At the same time, the crude protein content increased by 9.37%, and the acid-soluble protein content increased by 316.17%, with the total antioxidant capacity increased by 108.85%.This shows its obvious potential in degrading pectin in fruit pomace and improving nutritional value.

To address the challenges of poor degradation, low liquid absorption rates, and lack of antibacterial properties in existing materials, this study developed a highly absorbent chitosan/gelatin composite gel sponge for cold meat preservation.Citric acid was used as a crosslinking agent, 2,2,6, 6-tetramethylpiperidine-n-oxide(TEMPO) oxidized nanocellulose as a reinforcing agent, and oregano essential oil was incorporated into the composite.The physical structure of the sponge was characterized using Fourier infrared analysis, X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy analysis, while its formability, swelling property, mechanical strength, and porosity were evaluated.The efficacy of the sponge mat in preserving chilled fresh meat was tested under 4 ℃ storage conditions.Results indicated that citric acid crosslinking induced a porous structure due to frozen ice crystals.When 30% citric acid and 7% TOCNF (mass score, based on chitosan and gelatin) were added, the composite sponge demonstrated excellent water absorption and mechanical properties.The incorporation of OEO via immersion further enhanced the antibacterial performance of the sponge.During chilled meat storage, compared to non-absorbent and commercial absorbent mat groups, the chitosan/gelatin composite sponge pad group loaded with OEO exhibited significantly higher juice absorption rates (P<0.05).This effectively absorbed excess pork juice, significantly reduced volatile base nitrogen content and total colony counts in chilled meat, and inhibited microbial growth.Consequently, the shelf life of cold meat was extended from 4 days to 8 days.

Costunolide, the simplest sesquiterpene lactone, has potent anti-inflammatory and antitumor properties and has been investigated as a potential anticancer agent for various tumors in recent years.However, conventional acquisition methods such as chemical synthesis and plant extraction have proven inadequate to meet the demand for sustainable development.Consequently, the synthesis of costunolide using microbial cell factories has emerged as a viable alternative.This study successfully constructed the costunolide biosynthesis pathway by utilizing Escherichia coli BL21 (DE3) as the host organism and glucose as the carbon source, overexpressing the enzyme germacrene A synthase, germacrene A oxidase, costunolide synthase, the cytochrome P450 reductase, and introducing the exogenous mevalonate pathway.Through a series of strategies including screening of expression system and costunolide synthase, supplementation with heme precursors, introduction of metabolically engineered strains, optimization of fermentation conditions, and final produced 6.19 mg/L costunolide in shake flasks, which represents an 81-fold increase compared with the starting strain.The results demonstrated the feasibility of utilizing microbial bacterial cell factories for the synthesis of costunolide and provided a reference strategy for the synthesis of other sesquiterpene lactones.

This study aimed to clarify the antibacterial effect and mechanism of trans, trans-2,4-nonadienal (E24 N) on Colletotrichum acutatum, the dominant postharvest pathogen of loquat.The effects of different concentrations of E24 N on C.acutatum were investigated by physicochemical analysis and microstructural observation.Results showed that the minimum inhibitory concentration and minimum bactericidal concentration of E24 N against C.acutatum determined by the agar dilution method were both 0.4 mL/L.The germination of spores treated with 0.05 mL/L E24 N solution for 12 hours was only (7.01±1.98)%, significantly lower than the control group spore germination rate of (85.41±4.75)% (P<0.05).Observations of morphological changes in C.acutatum using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that treatment with E24 N disrupted the fungal hyphae, destroyed the integrity of the cells, and rendered the organelle structures unrecognizable.Additionally, treatment with E24 N altered the cell permeability of C.acutatum, leading to the leakage of proteins and nucleic acids, an increase in relative conductivity, enhanced lipid peroxidation in the membrane, and accumulation of reactive oxygen species.The results of the fruit experiment indicated that treating loquat fruits with E24 N could delay the progression of anthracnose in loquat fruits, with an inhibitory effect superior to that of citral, a commonly used aliphatic aldehyde preservative in production.In conclusion, E24 N inhibited the germination of C.acutatum spores and mycelial growth, disrupted its cellular structure, and promoted lipid peroxidation and the accumulation of reactive oxygen species, thereby affecting its normal physiological functions and suppressing the occurrence of anthracnose on loquat fruits.This study provides new theoretical evidence for the application of aliphatic aldehyde compounds in the prevention and control of anthracnose in loquats.

To explore the impact of cold stress on the activity of freeze-dried lactic acid bacteria, Lacticaseibacillus rhamnosus B6 was selected as the research subject.Seven protectants and various cold stress treatments were evaluated for their protective effects during freeze-drying.Additionally, this study explored the patterns of changes in survival rate, acidification capacity, lactate dehydrogenase activity, and cell membrane integrity of strain B6 under various cold stress temperature and durations.Results indicated that 100 g/L skim milk was the optimal protectant, achieving a high freeze survival rate of 79.30%.This survival rate was significantly higher than that of other protectants (P<0.05).With 100 g/L skimmed milk as protective agent, the survival rate of freeze-drying could reach (97.94±1.1)% under cold stress at 4 ℃ for 2 h.Compared with the group without cold stress treatment, the survival rate of cold stress at 4 ℃ for 2 h increased by 18.64%.Moreover, the effect of this cold stress condition was significantly better than other cold stress conditions (P<0.05).Furthermore, results showed that cold stress at 4 ℃ for 2 h could significantly improve the acidification ability and lactate dehydrogenase activity of L.rhamnosus B6 after freeze-drying, and maintain the integrity of cell membrane.Therefore, this study demonstrated that cold stress treatment was an effective method for preserving the viability of freeze-dried L.rhamnosus.

Flaxseed cake is a byproduct of oil processing, with a dietary fiber content of up to 40 to 45, of which soluble dietary fiber (SDF) accounts for about 12.SDF has good physiological functions and great potential for development and application.Based on this, this study used flaxseed cake as the raw material and explored the distribution characteristics of the basic components of flaxseed cake.In depth, the differences in SDF extraction efficiency among different extraction methods were investigated, and an efficient acid precipitation protein enzymatic starch method was constructed for the extraction of SDF from flaxseed cake.The optimal extraction process parameters were optimized as follows:solid-liquid ratio of 1∶20(g∶mL), ultrasound time of 30 min, and amylase addition of 0.9.Under these process conditions, the extraction rate of SDF reached 85.32, significantly higher than that reported in similar literature.The structural characterization results show that the average molecular weight of flaxseed SDF was 531.691 kDa, and the molecular conformation presented an irregular curved shape.It is an acidic heteropolysaccharide with a rough surface, dense particles, and composed of monosaccharides such as xylose, fucose, galacturonic acid, and galactose.

Proteolytic enzymes play crucial roles in soy sauce fermentation.To improve the utilization rate of raw materials and soy sauce quality, this research aimed to characterize the enzymatic properties of proteolytic enzymes produced by Bacillus amyloliquefaciens BS5582 and evaluate its application in soy sauce fermentation.The optimal temperature and optimal pH value of enzymes were 50 ℃ and pH 7.5, respectively.The half-life value at pH 6.0 reached 86.93 min, which was better than two commercial enzymes.Moreover, this enzyme also had a relatively high tolerance to high salinity since it could still maintain around 50% activity after treatment at 140 g/L salinity for 15 days.Finally, the proteolytic enzymes produced by the BS5582 strain were applied in the initial stage of soy sauce fermentation.Results showed that the addition of BS5582 enzymes could significantly increase the concentrations of amino acid nitrogen and the quantity and concentration of volatile flavor substances in soy sauce.The soy sauce samples fermented with the addition of proteolytic enzymes also had a stronger fruity aroma, sauce aroma and smoky aroma, which endowed soy sauce with a more pleasant aroma and more mellow taste.The results obtained in this study showed that the proteolytic enzymes produced by B.amyloliquefaciens BS5582 had the good enzymatic ability and benefited the flavor and quality of soy sauce, indicating the enzyme had potential application value in soy sauce production.

This study used network pharmacology and molecular docking technology to explore the inhibitory mechanism of active ingredients in Glycyrrhiza uralensis on pathogenic Escherichia coli and verified by in vitro bacteriostatic test.The active ingredients and targets of G.uralensis were screened in TCMSP databases.Genecards and OMIM databases were searched for targets that inhibit E.coli.The jvenn platform was used to obtain intersection targets.The protein-protein interaction (PPI) analysis of the intersection targets was performed using the STRING platform, followed by GO function and KEGG pathway enrichment analyses using the Metascape platform.After obtaining the key targets inhibiting 5 pathogenic E.coli, the effect of primary active ingredients was identified by molecular docking and in vitro bacteriostatic test.After screening, 86 active ingredients and 93 intersection targets were obtained.Through GO and KEGG enrichment analysis, G.uralensis mainly affected biological processes such as response to xenobiotic stimulus and response to molecule of bacterial origin, and pathways like pathways in cancer, lipid and atherosclerosis pathways.Key targets for inhibiting 5 pathogenic E.coli were IL6, TP53, and STAT3, and molecular docking showed that the naringenin, isoformononetin, and 3″-methoxyglabridin exhibited high binding energy to these targets.The minimal inhibit concentration of above 3 active ingredients against 5 pathogenic E.coli varied between 0.16-0.31, 0.62-1.25, and 0.07-0.16 μg/mL, respectively, and minimum bactericidal concentration varied between 0.16-0.62, 1.25-2.50, and 0.16-0.31 μg/mL, respectively.3″-Methoxyglabridin displayed the best antibacterial activity.This study provides the basis for exploring the mechanism of G.uralensis in inhibiting E.coli and key active ingredients in G.uralensis for inhibiting pathogenic E.coli.

Peel color is an important factor affecting the appearance and quality of citrus fruits, which directly influences consumer preferences.An unsynchronized ripening phenomenon of peel and flesh widely exists in early-maturing mandarin fruits harvested from Chongqing, the previous study found that 661 nm red LED light irradiation was an effective means to promote the coloration of early mandarin fruit.Based on the transcriptome data of red LED light irradiation-treated fruit, it was found that the transcription factor CcbHLH130 (Ciclev10005233 mg) might play an important role in red LED irradiation-promoted coloration of early-maturing mandarin fruit peel.The CcbHLH130 CDS sequence was cloned from the rind of mandarin fruit in the Chongqing area and characterized for biological information and transcription factors.Results showed that CcbHLH130 was highly homologous to Arabidopsis AtFBH4, and was also localized in the nucleus with transcriptional activation activity, and its promoter region had a light response element, abscisic acid response element, and gibberellin response element.After performing transient transformation of CcbHLH130 in tobacco leaves, the leaves at the site of transient transformation were significantly yellowed on the second day, and the contents of chlorophyll a and abscisic acid chlorophyll b were significantly reduced (P<0.05).After transient overexpression of CcbHLH130 in mandarin fruits, the relative expression level of CcbHLH130 in the peel increased significantly on the first day (P<0.05), the expression levels of chlorophyll degradation-related genes CcNYC1, CcChlase1-2, CcHCAR, and CcRCCR was significantly up-regulated at day 2 after the transient transfer (P<0.05), and an obvious color change was found in the peel on the third day, accompanied by a significantly reduce in the contents of chlorophyll and its metabolites (P<0.05).Taken together, CcbHLH130 may accelerate the color change of mandarin fruits by promoting the degradation of chlorophyll.

This study aimed to optimize the preparation process of nanopeptides from distiller’s grains and investigate their structural, antioxidant, and gastrointestinal digestive stability properties.Through SDS-PAGE analysis, this study selected alkaline protease to hydrolyze the alcohol soluble protein in distiller’s grains to prepare peptides, and optimized the enzymatic conditions based on response surface methodology as follows:enzymatic temperature 60 ℃, enzymatic time 3 h, and enzyme addition 1.87% (w/w).The peptides of distiller’s grains prepared showed strong antioxidant activity, with a significantly higher DPPH free radical scavenging ability than glutathione.This study further prepared nanopepetides distiller’s grains by thin film emulsification ultrasonication method, and the results of Z-average mean, polydispersity index, and Zeta potential analysis showed that the nanopeptides had excellent size homogeneity [(155.80±1.92) nm] and high stability.In addition, Fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy analysis showed that the wine nanopeptides bound to the liposome membrane through electrostatic and hydrophobic interactions, forming a stable composite structure.In the in vitro gastrointestinal digestion experiment, the nanopeptides showed stability in gastric digestive fluid, while showing a rapid release characteristic in intestinal digestive fluid, with a cumulative release rate of (35.20±0.08)%.In summary, gastrointestinal digestive presented advantageous stability and bioactivity, and have good application prospects in functional food field.

To improve the acid-induced gel properties of oat protein isolate (OPI) and thus expand its applications, the effects of different concentrations of sodium alginate (SA, 0, 0.5, 1.5 g/L) and glucono-delta-lactone(GDL, 5%, 10%, 20%, mass fraction, based on the dry weight of the protein) on the acid-induced gel properties of oat protein were investigated.Results showed that hydrophobic interactions and hydrogen bonding in the gels were significantly enhanced with the increase of SA concentration, which promoted the transformation of the gels from particle aggregation-like or sheet-like aggregates to uniform and porous gel networks.When the GDL content was increased from 5% to 10%, the electrostatic repulsion in the gel was weakened and the hydrophobic interactions were enhanced, which contributed to the transformation of the OPI-SA gel from an obvious phase-separated structure to a homogeneous three-dimensional network structure, and when the GDL content was increased to 20%, the formation of a more tightly-coupled gel network was due to the electrostatic attraction, and the homogeneous and porous three-dimensional network structure contributed to the improvement of the gel strength, thus, the SA concentration of 0.1% and GDL concentration of 10% resulted in the highest gel hardness of 226.25 g.Overall, SA and GDL can be used to modulate the microstructure and gel properties of acid-induced OPI gels and to expand the range of applications of oat proteins.

4-Vinylguaiacol (4-VG) is widely used in the pharmaceutical, cosmetic and food industries and has important commercial value.At present, it is mainly synthesised by chemical methods, which are not environmentally friendly and have by-products.The biological synthesis of 4-VG by non-oxidative decarboxylation of ferulic acid (FA) catalyzed by phenolic acid decarboxylase (PAD) is considered to be a promising method.However, the inhibition effect of FA and 4-VG leads to a low conversion rate, low product concentration, and no reusability, which limits the practical application of this method.In this study, the phenolic acid decarboxylase (Bapad) from Bacillus atrophaeus was displayed on the surface of S.cerevisiae (SD-Bapad) and expressed in Pichia pastoris to compare its enzymatic properties and tolerance to high concentrations of substrates, products and organic solvents.Subsequently, a two-phase reaction system was used to produce 4-VG in a 5 L bioreactor using SD-Bapad.Results showed that SD-Bapad retained 54.7% of the relative enzyme activity after incubation at 55 ℃ for 1 h, and retained more than 65% of the relative enzyme activity after incubation at pH 3 and 10 for 1 h, while the free enzyme was almost inactivated, and showed stronger tolerance under high concentration of substrates, products and organic solvents.In addition, SD-Bapad still maintained 63% enzyme activity after repeated use in the organic / water two-phase system 6 times.Finally, FA was efficiently converted to 4-VG in a 5 L reactor using SD-Bapad as a whole-cell catalyst.Efficient conversion of FA to 4-VG yielded approximately 157.4 g/L (1 047.9 mmol/L) within 20 hours, the yield was about 7.9 g/(L/h), and the molar conversion rate was about 84.8%.Results showed that the surface display technology of S.cerevisiae could significantly improve the stability and reusability of Bapad, which provided a new way and potential solution for industrial biological production of 4-VG.

5-Aminolevulinic acid synthase (5-ALAS), a pyridoxal phosphate-dependent decarboxylase within the α-oxoamine synthase family, catalyzes the condensation of glycine and succinyl-CoA to produce 5-aminolevulinic acid (5-ALA).However, the low activity and poor thermal stability of most ALAS enzymes hinder their application in industrial production.In this study, molecular engineering was conducted on RpALAS derived from Rhodopseudomonas palustris to enhance its catalytic activity and thermal stability.Through rational design using the online tools Fireprot and HotSpot Wizard, this study successfully developed a mutant enzyme, M4 (T73L/L252F/T396M), which demonstrated remarkable improvements in thermal stability.This mutant not only exhibited a 5% increase in enzyme activity but also had an optimal reaction temperature that was 8 ℃ higher and an optimal pH that shifted 0.5 units towards neutrality compared to the wild type.The half-life (t_1/2) of mutant M4 at 45 ℃ reached 214.43 minutes, which was 8.9 times that of the wild type.Molecular dynamics simulation analysis revealed that the enhanced hydrophobic interactions and changes in steric hindrance within the protein were key factors contributing to the improved thermal stability of the enzyme.This study successfully obtained an ALAS mutant with excellent thermal stability, which not only enriched the library of ALAS mutants but also provided important experimental evidence and theoretical references for a deeper understanding of the relationship between ALAS structure and function.

In this study, firstly, based on the walnut meal, different kinds of proteases and different molecular weight ultrafiltration membranes (30, 5, 3, 1 kDa) were combined to screen the enzymatic solution fractions, and the fractions with the higher scavenging rate of DPPH free radicals and the reducing power were obtained.Subsequently, they were added to walnut oil, by measuring four oxidation indicators including peroxide value (POV), acid value (AV), P-anisidine value (P-AV), and conjugated diene value (CDV), as well as using gas chromatography-ion migration spectrometry (GC-IMS) to determine flavor components, the study explores the impact of antioxidant peptides on the oxidative stability of walnut oil at different storage stages under accelerated storage conditions at 60 ℃.Finally, a mathematical model was established by the peroxide value and the shelf-life prediction was completed.Results showed that the best antioxidant activity was obtained from the peptide <3 kDa after neutral protease digestion, and the POV, AV, P-AV, and CDV of the sample group were effectively reduced by the addition of 0.2 g/kg of peptide powder compared with that of the control group, and the contents of volatile components with irritating odors (e.g., allyl isothiocyanate, 2-methyl-2-pentenal, hexanenitrile, dimethyl trisulfide, etc.) were significantly lower than that of the control group on the 12th day of storage.In addition, the model prediction also showed that the shelf-life of the sample group at 25 ℃ was 48.3% higher than that of the control group.It could be seen that the addition of antioxidant peptides could delay the oxidation of fats and oils, play a certain positive effect on the flavor of fats and oils, and improve the quality of fats and oils.

This study aimed to improve the functional properties of mulberry leaf black tea.The effects of different anaerobic treatments on the content of γ-aminobutyric acid (GABA) and other active ingredients in mulberry leaf black tea, as well as its antioxidant activity, were investigated.The results showed that anaerobic processing significantly increased the GABA content in mulberry leaf black tea, especially the anaerobic/aerobic alternating treatment, which could significantly enhance the activity of glutamate decarboxylase and facilitate the decarboxylation of glutamate into GABA.After 4 hours of anaerobic treatment, the GABA content in mulberry leaf black tea exceeded that of Gabaron tea.Moreover, the highest GABA content was found in mulberry leaf black tea treated with three cycles of anaerobic/aerobic alternation (1.97±0.02) mg/g, which was 1.68 times that of the control group.The content of free amino acids, total flavonoids, and polyphenols in mulberry leaf black tea treated with three cycles of anaerobic/aerobic alternation increased by 38.99%, 25.83%, and 20.36%, separately, while the content of soluble sugars and water extracts decreased by 16.89% and 8.57% in comparison with the control group.In addition, the scavenging rate of ABTS cation free radical, DPPH radical, hydroxyl radical, and iron ion-reducing power of mulberry tea treated with three cycles of anaerobic/aerobic alternation were 2.52, 2.29, 1.84, and 1.03 times higher than that of the control group, separately.Correlation analysis revealed that polyphenol content exhibited the strongest correlation with hydroxyl radical scavenging capacity, while GABA content showed the highest correlation with DPPH free radical scavenging capacity and iron ion reducing power.This study provides a theoretical reference for the development of GABA-enriched functional mulberry tea.

To optimize the dough network structure and enhance the noodle processing quality of wheat flour, magnetic field technology was employed to treat wheat flour.The study examined the effects of magnetic field intensities (0, 2, 4, 6, 8, 10 mT) on dough water distribution, mixing characteristics, rheological properties, and noodle quality.Results showed that increasing magnetic field strength (0-8 mT) facilitated water binding in starch-protein complexes.This increased gluten resistance and promoted elastic gel network formation.Furthermore, magnetic field-treated wheat flour significantly enhanced textural properties and cooking performance in resultant noodles (P＜0.05).Wheat flour treated at 8 mT observed optimal performance, including bound water content increased by 22.27%, cooking loss decreased by 20.76% and tensile elongation improved by 25.96% compared to untreated controls.Magnetic field treatment induced structural reorganization of gluten proteins and starch molecules.The resulting ordered molecular alignment improved the continuity and stability of the dough matrix.The analysis confirmed that magnetic field modification produced denser and more stable dough networks, demonstrating its effectiveness for premium noodle production.

Trehalose, a colorless, odorless, and chemically stable natural disaccharide, plays a vital role in moisture retention, radiation resistance, and biomolecular structure protection.It is typically produced through a dual-enzyme catalytic process;however, the conversion rate remains low.This study successfully constructed an Escherichia coli expression system for maltooligosyltrehalose synthase (MTSase), maltooligosyltrehalose trehalohydrolase (MTHase), and 4-α-glucanotransferase (4αGT), thereby establishing a three-enzyme catalytic system.Through systematic optimization, a significant improvement in the trehalose conversion rate was achieved.Initially, MTSase, MTHase, and 4αGT were integrated into the pBAD vector and solubly expressed in E.coli TR07.To further enhance the expression levels, bioinformatics tools were utilized for sequence optimization, resulting in recombinant strains TR07-1^* (expressing MTSase) and TR07-3^* (expressing 4αGT), which demonstrated 87% and 52.8% increased in enzyme activity, respectively, compared to the unoptimized strains.Additionally, six protein fusion tags (glutathione S- transferase,maltose binding protein,N-utilization substance A,protein disulfide isomerase,small ubiquitin-related modifier,thioredoxins) were fused to the N-terminus of the enzymes, and fermentation parameters, including induction temperature, inducer concentration, and OD₆₀₀ at induction, were optimized.These modifications further improved the enzyme activities of MTSase and MTHase by 31.9% and 15.2%, respectively.Ultimately, the optimized recombinant E.coli system increased the trehalose conversion rate from 78.65% to 83.33%.This study provides a valuable reference for the industrial-scale production of trehalose.

In this paper, 15 kinds of potatoes in Enshi area were used as raw materials, using Shu-kang processing technology, and the volatile components of the products were determined by GC-MS and gas chromatography-ion mobility spectrometry (GC-IMS).Results showed that a total of 39 volatile components were identified by GC-MS method, mainly aldehydes, pyrazines, esters, and alkanes, and n101 had the highest total volatile flavor material content, followed by e7.Odor activity value analysis showed that nonanal, trans,trans-2,4-heptadienal, decanal, 2-ethyl-3,5-dimethylpyrazine, 2-amylfuran, and 4-hydroxy-3-methoxystyrene were characteristic flavor substances of potato made from Shu-kang potatoes.Cluster analysis revealed that the volatile components of e7, e11, and Mira were similar, primarily exhibiting floral and fatty aromas.The volatile components of e3 and e14 were also similar, and these types of Shu-kang potatoes showed an additional roasted aroma on the basis of floral and fatty aromas.A total of 46 volatile components were isolated and identified by GC-IMS, mainly aldehydes.Both fingerprint comparison and cluster analysis revealed that the volatile components of e7, e11, and Mira were similar, as were those of e3 and e14, which was consistent with the results of GC-MS.Through the above results, it could be seen that there are differences in the content of volatile components in different varieties of Shu-kang potatos, and the corresponding potato varieties could be selected according to the needs of processed products.

Walnut protein isolate (WalPI) was used as a raw material for cold plasma (CP) treatment and sodium alginate (SA) modification, aiming to investigate the effects of different CP treatment voltages on the structure and properties of WalPI-SA.The results of SDS-PAGE showed that the bands of CP-treated WalPI-SA became lighter in color in the gel electrophoresis lanes, indicating that the subunit of WalPI was involved in the binding of WalPI to SA.The ultra violet(UV) absorption spectroscopy, fourier transform infrared (FTIR) spectroscopy, and fluorescence spectroscopy analyses showed that CP treatment loosened and depolymerized the structure of WalPI and promoted WalPI-SA intermolecular interactions.Scanning electron microscope observation revealed that the surface of untreated WalPI was smooth, whereas the surface roughness of CP-treated WalPI-SA increased, and the pore structure increased, which provided more reaction sites.The particle size and zeta potential of WalPI-SA were 524 nm and -30 mV, respectively, at a CP treatment voltage of 80 V.The particle size of WalPI-SA was the smallest under this condition, and the intermolecular charge of WalPI under this condition, the particle size of WalPI-SA was the smallest, the intermolecular charge of WalPI-SA reached the maximum, and the strong electrostatic interactions inhibited the aggregation of the particles, and the stability of the system was improved.The results of differential scanning calorimetry analysis showed that the thermal stability of CP-treated WalPI-SA was enhanced.The grafting degree and browning degree of WalPI-SA showed a tendency of increasing and then decrease with the increase of CP treatment voltage and reached the maximum values at 80 V, which were 25% and 0.52%, respectively.The results of surface hydrophobicity indicated that CP treatment could reduce the surface hydrophobicity of WalPI-SA and enhance its hydration characteristics.In conclusion, CP treatment can effectively improve the properties of WalPI-SA and enhance its application in food processing.

To improve the antibacterial properties of packaging films, the antibacterial and antioxidant properties of composite preservative solution made from varying ratios of chitosan (CS) and cell-free supernatant (CFS) of lactic acid bacteria were investigated.Composite packaging films were prepared by varying the volume ratios of CS to CFS (15∶0, 10∶1, 10∶2, 10∶3, 10∶4, 10∶5) were prepared using CS as the film-forming matrix.The effects of different CFS ratios on the morphology, structure, mechanical properties, and barrier properties of the films were evaluated.The antibacterial and antioxidant effects of the composite preservative solution were positively proportional to the additional amount of CFS, reaching their maximum values at a CS to CFS ratio of 10∶5.The inhibition zone diameters against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa was 14.68, 15.83, and 13.40 mm, respectively.DPPH free radical and ABTS cationic radical scavenging rates were 94.46% and 92.24%.With the increase in CFS content, the composite film exhibited improved light barrier properties compared to the pure CS film, along with increased thickness, water vapor permeability, water solubility, and water content, while CO₂ permeability decreased.The mechanical properties and thermal stability of the composite film were optimal at a CS to CFS ratio of 10∶3.The tensile strength and elongation at break increased by 36.77% and 70.94% compared with the pure CS film (P＜0.05), and the melting temperature reached 125.28 ℃.Characterization analysis showed that the composite film exhibited excellent compatibility, dense structure, and enhanced stability.

In Xinjiang, fruit tree resources are abundant and diverse, but have not been fully developed and utilized.By detecting and analyzing the components during the production process of the smoke liquid, suitable fruit trees could be chosen as the raw material source for the smoke liquid.In this experiment, the smoke liquid was extracted from four spices, including pear wood, begonia wood, walnut shell, and red willow branch using the dry distillation pyrolysis method, and refined using macroporous adsorption resin XAD-4.A comprehensive detection and analysis of the physicochemical properties and key parameters of these four refined smoke liquids were conducted, and then gas chromatography ion mobility spectroscopy (GC-IMS) was used to conduct an in-depth analysis of the volatile flavor components in different types of smoke liquids.Results showed that there were significant differences in the quality of the four refined smoke liquids.The highest pH value of the begonia wood smoke liquid was 2.94, and the lowest was 2.15 for the red willow branch smoke liquids.The L^* values of the four smoke liquids products were 11.08-19.97, a^* values were 4.66-13.87, and b^* values were 7.25-22.45.The highest total phenols content was found in the red willow branch smoke liquid, reaching 17.88 mg/mL, and the highest carbonyl compound content was found in the walnut shell smoke liquid, reaching 18.57 g/100 mL, all of which were undetected 3,4-benzo (a) pyrene.A total of 65 volatile organic components were identified in four types of smoke liquids.Through fingerprint analysis, there were differences in the characteristics of volatile organic compounds among these four smoke liquids.The results of the principal component analysis showed that the smoked liquids prepared from different fruit trees had different characteristic flavors, which were consistent with the sensory evaluation results.Among them, the aroma of walnut shell smoke liquid was evenly distributed, with rich flavors, and was more popular among people.Through clustering heatmap analysis, the results of fingerprint spectra and principal component analysis can be visually verified.To study smoke liquid and widely apply them in the future food industry, it is necessary to enrich the types of smoke liquid, which will provide reference for related research and applications.

This study investigated the protective effects of glutamine peptides (Gln-P) on ethanol-induced damage in GES-1 cells.Initially, to assess the stability of Gln-P throughout simulated gastrointestinal digestion, molecular weight distribution was utilized as a key evaluation criterion.Subsequently, an ethanol-damaged GES-1 cell model was established for evaluating resistance against oxidative stress of Gln-P and its effects on cellular barriers.The analysis encompassed key parameters such as the fluorescence intensity of intracellular reactive oxygen species (ROS), oxidative damage markers, superoxide dismutase (SOD) activity, glutathione (GSH) levels, and glutathione peroxidase (GSH-Px) levels.Results indicated that Gln-P maintained over 98.5% of its molecular weight after digestion, demonstrating robust digestive stability.Notably, Gln-P and its peptide fragments pEQ and LQ exhibited concentration-dependent reductions in ROS accumulation, malondialdehyde (MDA) content, and enhancements in SOD activity, GSH, and GSH-Px levels.Specifically, at a concentration of 800 μg/mL, Gln-P effectively mitigated ROS levels and enhanced GSH-Px activity.Additionally, LQ at 60 μg/mL demonstrated the most pronounced reduction in MDA, while pEQ at 60 μg/mL exhibited the highest increase in SOD activity.Notably, all these effects were statistically significant compared to the model group (P<0.05).This research highlights Gln-P’s considerable potential to strengthen GES-1 cells against ethanol damage.It also contributes to the advancement of therapeutic and reparative strategies aimed at addressing alcoholic gastric mucosal injury and protecting the gastric barrier.

In this study, cinnamon essential oil (CEO) was combined with clove essential oil (CO) to serve as CEO:Pickering essential oil (nanoemulsion, CEON) was prepared using cellulose nanocrystals (CNC) -stabilized complex essential oil CEOs with a volume ratio of CO=3∶1 as the optimal ratio.The CNCs-CEOCO Pickering emulsion composite film was prepared and formed using chitosan (CS) as the film-forming substrate.The mechanical properties, barrier properties and microstructure of CEON bio-based packaging films with particle size of CEON and different mass fractions of compound essential oil CEOs (0%, 0.5%, 1.0%, 1.5%, and 2%) were studied.In addition, the preservation effect of the composite film during the 12-day storage of beef intestines was also studied.The results show that CEON has good compatibility with CS.Moreover, with the increase of CEOs concentration, the droplet size increases, the composite film gradually thickens, the elongation at break decreases, and the tensile strength decreases.In addition, as the hydrophobicity of essential oils affects the diffusion path of water molecules in the emulsion, the composite film with a denser microstructure has a lower water vapor permeability coefficient, thereby preventing water penetration.Moreover, through the preservation of beef sausages, it was found that as the concentration of CEOs in the membrane increased, the antioxidant and antibacterial activities of the membrane also increased, which could effectively extend the preservation time of beef sausages.The composite film with a 2%CEOs concentration added has a significant antioxidant and antibacterial effect on sausages during storage.Therefore, the composite film with an CEOs concentration of 2% has the best effect.

In this study, thermoplastic starch was obtained by mixing chestnut starch (CS) with esterified chestnut starch (ERCS) at a mass ratio of 5∶2, formulating a solution with a mass fraction of 10%, and adding different amounts of the plasticizer 1,3-bis(hydroxymethyl)urea (DMU) for gelatinization preparation.The structure and morphology of thermoplastic starch with different components were characterized by Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analyzer (TG), and the best plasticizing effect was achieved at a DMU dosage of 25% of the total quality of starch with the strongest hydrogen bonding between the plasticizer and chestnut starch.It was prepared as a thermoplastic starch film, and the light transmittance, water resistance, mechanical properties, and degradation of the film were tested and analyzed.The light transmittance could reach up to 79.25%, the water absorption rate was significantly reduced, the tensile strength and the elongation at break were 4.41 MPa and 16.31%, respectively, and the stability was slightly improved.

In this study, fresh green walnuts and walnut kernels were vacuumed and treated with deoxidizers, respectively, and then stored at -18 ℃ for six months.The effects of different treatments on walnut quality were explored by analyzing the color, hardness, weight loss rate, oil quality (fat content, peroxide value, acid value, malondialdehyde), soluble protein, total antioxidant capacity, fatty acid composition, and volatile flavor.Results showed that vacuuming and deoxidizing agent treatments were superior to the control group without any treatment in delaying the browning of fresh green walnuts and walnut kernels, maintaining hardness, reducing weight loss rate, slowing down the increase of peroxide value, acid value, and malondialdehyde, and maintaining the flavor characteristics of fresh walnuts during storage.Vacuuming treatment better maintained the quality of fresh walnuts and walnut kernels with green skin after six months of storage.Comprehensive analysis showed that vacuum treatment could effectively delay the quality deterioration of fresh walnuts and fresh walnut kernels with green skin during frozen storage.This result provides a scientific reference for the frozen storage and preservation of fresh walnuts.

Ultrasonication and alternating anaerobic-aerobic treatment conditions can significantly enhance the accumulation of γ-aminobutyric acid (GABA).However, the mechanism by which the ultrasound combined with alternating anaerobic-aerobic conditions promotes GABA accumulation through influencing the GABA shunt and polyamine degradation pathways remain unclear.In this study, mulberry leaves were selected to elucidate the molecular mechanisms underlying GABA accumulation by comparing changes in relevant metabolite content, enzyme activity, and gene expression among mulberry leaves treated with ultrasound, alternating anaerobic-aerobic treatment, and their combination, with or without aminoguanidine hydrochloride (AG).The results demonstrated that GABA content increased by 3.0, 5.0, and 6.7-fold after ultrasound, alternating anaerobic-aerobic treatment, and their combination, respectively.These treatments not only enhanced the activity and gene expression of glutamate decarboxylase and calmodulin gene expression, thereby improving the capacity of the GABA shunt to accumulate GABA, but also increased the polyamine levels, enhanced the activities of diamine oxidase, polyamine oxidase (PAO), and aminoaldehyde dehydrogenase, and upregulated PAO gene expression.The contribution of the polyamine degradation pathway to GABA accumulation in mulberry leaves under ultrasound, alternating anaerobic-aerobic treatment, and their combination was 28%, 30%, and 37%, respectively, indicating that GABA accumulation primarily relies on the GABA shunt.These findings suggest that ultrasound combined with alternating anaerobic-aerobic treatment significantly promotes the efficient accumulation of GABA in mulberry leaves by activating key enzyme activities and gene expression in both GABA shunt and polyamine degradation pathways.This study provides scientific evidence and technical support for the development of GABA-enriched mulberry leaf tea and functional foods.

Using strawberry juice as the raw material, the mixed fermentation conditions of Lactiplantibacillus plantarum 85 (LP85) and Streptococcus salivarius subsp.thermophilus 81 (ST81) were optimized.Compared to fresh fruit juice, a comprehensive analysis was conducted on the sensory scores, physicochemical indicators, and volatile compound composition of the pasteurized strawberry fermented juice.Cell experiments were employed to reveal its nutritional benefits.Results from the orthogonal experiment revealed that optimal fermentation conditions were a 3∶1 ratio of LP85 to ST81 at a concentration of 10⁷ CFU/mL, with 100 g/L sugar addition, an initial pH of 4.0, fermentation at 37 ℃ for 14 hours, followed by pasteurization for 30 minutes (T14-5).Fermentation improved sensory scores, reduced browning, and enriched the contents of phenolic compounds and antioxidant properties.Headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis identified 47 volatile flavor compounds, predominantly esters, in the fresh juice and T14-5, with significant increases in n-octanal and ketones in T14-5 compared to the fresh juice.T14-5 significantly increased the cell viability of lipopolysaccharide-induced inflammatory RAW264.7 cells in a dose-dependent manner, reduced levels of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), monocyte chemoattractant protein-1 (MCP-1), nitric oxide (NO), prostaglandin e2 (PGE2), and interleukin-6 (IL-6).In addition, T14-5 alleviated insulin resistance and apoptosis in high-glucose-induced HepG2 cells, while enhancing glucose consumption, alongside with the downregulation of glucose-6-phosphatase (G6pase), glycogen synthase kinase-3β (GSK3β), and toll-like receptor 4 (TLR4), and the upregulation of glucose transporter 4 (GLUT4), insulin receptor (INSR), and protein kinase B (AKT).Results provide a theoretical basis for the product development of pasteurized probiotic fermented strawberry juice, indicating its potential to become a healthy drink with commercial value.

This study aimed to understand the composition of lactic acid bacteria in yak milk from Shangri-La, Yunnan province and obtain valuable lactic acid bacteria resources.In this study, 170 strains of lactic acid bacteria were isolated from 10 yak milk samples in Shangri-La, Yunnan province by pure culture method, and were identified into 7 genera and 9 species by 16S rRNA sequencing technique.Among them, Lactobacillus helveticus was the species with the highest number of isolates (47.1%), followed by Lentilactobacillus diolivorans (23.5%) and Lacticaseibacillus paracasei (12.4%).To obtain good strains from yak milk at high altitudes, this study investigated the tolerance of lactic acid bacteria isolates.Firstly, the strains were evaluated for NaCl tolerance.It was found that three strains had good NaCl tolerance.The potential beneficial properties of strains were further screened.The strains were studied for their artificial gastrointestinal fluid tolerance and their ability to inhibit three common pathogenic bacteria in food.One strain of L.paracasei IMAU13337 was finally screened and evaluated for safety.It was demonstrated that strain IMAU13337 had good tolerance to artificial gastrointestinal fluids, antibacterial properties and safety.Therefore, it is show that L.paracasei IMAU13337 has the potential to be used as an excellent salt-tolerant lactic acid bacteria starter, which will provide basic data for the development and utilization of high-salt fermentation products.

Ergothioneine (EGT), a sulfur-containing histidine derivative, is widely used in the fields of food, cosmetics and pharmaceutical industries.While much of the current research on EGT biosynthesis focuses on well-characterized pathways in Mycolicibacterium smegmatis and Neurospora crassa, limited attention has been given to EGT synthases in edible and medicinal fungi, which are the primary natural sources of EGT.In this study, bioinformatics analysis and LC-MS were utilized to identify two key enzymes, PTR-Egt1 and PTR-Egt2, involved in EGT biosynthesis in the edible macrofungus Pleurotus tuber-regium.These enzymes were then co-expressed in Escherichia coli for efficient EGT production.Optimization of protein tags led to the selection of SUMO-tagged PTR-Egt1 and MBP-tagged PTR-Egt2 as the optimal recombinant configuration.Under 120 h fermentation conditions, EGT production reached 74.20 mg/L.Further optimization revealed that the addition of L-histidine significantly boosted EGT yield, achieving a maximum of 124.03 mg/L and a production efficiency of 1.03 mg/(L·h) after 120 hours with 1 g/L histidine supplementation.This study provides a systematic investigation into the function of EGT synthesis enzymes from P.tuber-regium and offers optimization strategies for heterologous expression, laying a solid foundation for the efficient biosynthesis of EGT in edible and medicinal fungi.

This study investigated the impact of capsicum oleoresin on the flavor profile of clear oil hot pot seasoning.Samples of clear oil hotpot base with 0%, 0.6%, 1.2%, 1.8%, 2.5% of capsicum oleoresin were prepared respectively, and the flavor changes of clear oil hot pot seasoning after capsicum oleoresin addition were comprehensively analyzed by two-dimensional gas chromatography-olfactometry-mass spectrometry (GC×GC-O-MS) and high-performance liquid chromatography-diode array detection (HPLC-DAD), and the effect of capsicum oleoresin on the volatile compounds of clear oil hot pot seasoning was analyzed by combining with the orthogonal partial least squares discriminant analysis (OPLS-DA).Results showed that 80 volatile compounds were detected, including 22 terpenoids, 22 aldehydes, 16 alcohols, 10 esters, 8 ketones, and 2 other compounds.With the addition of capsicum oleoresin, there was an increase in the content of various types of volatile compounds, with a notable impact on capsaicin levels, which were critical for spiciness.Combined with the sensory results, it was confirmed that the addition of chili oil resin could effectively enhance the flavor of clear oil hotpot base.The findings suggest that capsicum oleoresin can be strategically used to improve the sensory qualities of hot pot seasoning, offering valuable insights for the food industry.

This study was conducted to isolate and identify Monascus strains from various red yeast products and investigate its antimicrobial effects, and to characterize potential antimicrobial active substance employing metabolomics analysis. Five Monascus strains were isolated from red yeast rice/meal, among which strain H3-1 demonstrated obvious inhibitory effects against Aspergillus niger but showed no antibacterial activity against bacterial species.The strain was identified as Monascus purpureus by morphological and molecular analysis.Subsequent extraction of fermentation products using ethyl acetate and methanol revealed that only the ethyl acetate extract exhibited antifungal activity against A.niger.The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the crude metabolite extract were 0.625 mg/mL and 1.25 mg/mL, respectively.Metabolomic analysis identified 6 728 differential metabolites from the two extracts, with 1 935 upregulated and 4 793 downregulated compounds.Among them, the most abundant categories were amino acids/derivatives and benzene-related metabolites, occupying 20% and 17%, respectively.Notably, amino acids and derivatives accounted for 30% of the 30 most significantly upregulated metabolites.These findings suggested that derivatives and benzene-related metabolites may serve as the primary bioactive components responsible for the antimicrobial activity of H3-1.The results provide a scientific foundation for the development and utilization of Monascus-derived bioactive compounds.

Hydrogen sulfide (H₂S) is a toxic gas with a characteristic rotten egg odor.Elevated levels of H₂S in alcoholic beverages not only compromise their flavor but also pose health risks.Therefore, effective monitoring of H₂S concentration in such products is critical.This study developed a surface-enhanced Raman scattering (SERS) nanoprobe for the rapid and sensitive detection of H₂S in wine and beer.Firstly, gold nanostars (AuNSs), gold nanocubes (AuNCs), and gold nanospheres (AuNPs) were synthesized, and the donor molecule 4-nitrophenylthiophenol (4-NTP) was covalently attached to the nanoparticles via Au-S bonds to form three nanoprobes:AuNSs@4-NTP, AuNCs@4-NTP and AuNPs@4-NTP.Among them, AuNSs@4-NTP exhibited the strongest Raman enhancement and was selected as the optimal SERS nanoprobe for H₂S detection.Upon exposure to H₂S, the nitro group in 4-NTP was reduced to an amino group, resulting in a marked decrease in the Raman signal intensity of the nitro peak, thereby enabling sensitive detection of H₂S.Experimental results demonstrated that the SERS nanoprobe exhibited a good linear response to H₂S over the concentration range of 10-200 nmol·L^-1, with a detection limit of 3.24 nmol/L.The nanoprobe also exhibited high specificity for H₂S, with minimal interference from other substances.Furthermore, it was successfully applied to detect H₂S in commercial wine and beer samples, achieving recovery rates between 97.54% and 101.78%, highlighting its practical applicability.

To improve the high-value utilization of pig large intestine and facilitate the industrial transformation of local delicacy Dachang Tang, headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to detect and identify the volatile compounds in fresh pig large intestine (C), commercially available Dachang Tang (L, Y, U, S), and family-cooked Dachang Tang (F).The data were analyzed using odor activity values (OAV) combined with partial least squares discriminant analysis (PLS-DA).The flavor acceptability of Dachang Tang was assessed through sensory evaluation.Results indicated that Y and F received the highest sensory scores, but their flavors differed.The inherent aroma of pig large intestine was more pronounced in Y Dachang Tang, due to the presence of compounds such as 4-methylphenylacetone, 6-undecanone, (E, E)-2,4-decadienal, and a small amount of p-cresol.F exhibited a stronger spiced flavor, which was attributed to the introduction of flavor compounds like benzaldehyde, 4-methoxybenzaldehyde, linalool, eucalyptol, phenylethanol, eugenol, 4-allylphenyl ether, ethyl decanoate, α-phellandrene, and 3-ethyltoluene.The incorporation of these compounds significantly reduced the off-flavor compounds like 4-methylphenol, 3-methylindole, and indole found in C, thereby partially masking or reducing its off-odor.This study suggests that the Y and F samples can be considered as references for the industrialization of Dachang Tang to meet diverse consumer preferences.

To study the effect of storage methods on the quality of yak meat, the longissimus dorsal muscle of yaks was selected to be boiled, pan-fried, and roasted.Different storage methods include room temperature storage, cold storage, frozen storage, chilled-then-frozen storage, and frozen-then-chilled storage.The national standard was used to determine nutrient content and the LDA method was used to calculate sensory assessment scores.Results showed that the nutrient components, such as protein, moisture, and ash, remained intact in fresh meat and chilled meat.The nutrient losses were serious in frozen meat, chilled-then-frozen, and chilled-then-frozen meat.The ratios of polyunsaturated fatty acids to saturated fatty acids were ideal.The pH of the groups was within the normal range.The total volatile base nitrogen of fresh meat was the lowest, which was 3.12 mg/100 g.The meat colour, tenderness, cooking loss, pressing loss, and centrifuging loss of fresh meat and chilled meat were better than those of frozen meat, chilled-then-frozen meat, and frozen-then-chilled meat.The differences in shear force, texture, processing loss, and organoleptic evaluation of yak meat stored in different ways were significant (P<0.05).The shear force value of yak meat after processing increased compared with the shear force of edible quality.The results of organoleptic evaluation showed that, among the results, fresh meat after cooking had the best taste.The sensory evaluation results showed that the fresh meat after cooking had the best taste and the cold meat after frying and grilling had the best taste.Overall, the nutritional, eating, and processing qualities of fresh and chilled meat were better than those of frozen meat, chilled-then-frozen meat, and frozen-then-chilled meat, and the eating value was higher.Fresh meat is suitable for cooking and chilled meat is suitable for roasting and frying, which can provide theoretical references for controlling the quality of yak meat in market circulation.

To elucidate the flavor characterization of traditional roasted, pressed roasted, and cold-pressed sesame oils, gas chromatography-mass spectrometry (GC-MS) and two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOF/MS) were used to measure the volatile compounds of these sesame oils, compared the difference between results from two detection methods, and the flavor profile of each type sesame oil was illuminated by orthogonal partial least square discriminant analysis models (OPLS-DA).Results showed that the composition of volatile compounds detected by the two methods was significantly different.Specifically, the GC×GC-TOF/MS method identified 2.17 times more compounds than the GC-MS.However, the two results had the following similarities:(1) 71 compounds were detected in both methods;(2) the volatile compounds in two kinds of roasted sesame oils were primarily heterocyclic components with roasted, nutty and caramel flavors, while the volatile compounds of the cold-pressed sesame oil mainly consisted of alkenes and alcohols with herb flavor;(3) A total of 19 compounds were identified as the key volatile compounds in both orthogonal partial least square discriminant analysis models of two analysis methods.2-methoxyphenol, 3-ethyl-2, 5-dimethylpyrazine, 2-ethyl-6-methylpyrazine, and 2, 3, 5-trimethylpyrazine contributed significantly to the flavor of sesame oil;(4) The distribution of water-soluble and low boiling point volatiles in the two kinds of roasted sesame oils was significantly different.These findings suggest that the GC×GC-TOF/MS method could effectively complement the GC-MS method, and the combination of both GC-MS methods would enhance the analysis of volatile components in sesame oil.

This study aimed to explore the changes of volatile compoents and polyphenols during the solid-state fermentation of Zijuan black tea by Aspergillus chevalieri.The dynamic changes of volatile compoents and polyphenols were analyzed using gas phase ion mobility spectrometry (GC-IMS) technology and physicochemical composition determination.Moreover, the principal component analysis and cluster analysis were performed to reveal their patterns.The results showed that a total of 112 volatile compounds were detected by GC-IMS.And 100 compounds were qualitatively identified, mainly including alcohols, aldehydes, ketones, and esters.During the fermentation process, the content of dipropyl ketone, (E)-2-octenal and other substances decreased, while the content of propyl acetate and α-carvacene increased.The content of tea polyphenols and seven kinds of catechin monomers significantly decreased, the content of anthocyanins decreased and then increased, and the content of total flavonoids increased.This study demonstrated that fermentation with A.chevalieri significantly altered the volatile compoents and polyphenolic of Zijuan black tea, imparting woody and fungus aroma and reducing bitter and astringent components.It provides a theoretical foundation and novel insights for quality control of Zijuan black tea and utilization of purple tea resources.

Infant formula is the optimal breast milk substitute.This study compared lipid profiles of goat milk MFGM, soybean phospholipid, and egg yolk lecithin versus human milk fat globule membrane(MFGM) using untargeted lipidomics to elucidate key compositional differences.The analysis identifies 13 fatty acids and 548 phospholipid molecules across all samples.Palmitic acid (C16:0) and oleic acid (C18:1) emerge as the predominant saturated and unsaturated fatty acids.Comparative analysis reveals higher compositional similarity between goat milk MFGM and human MFGM, particularly in sphingomyelin content.Soybean phospholipid and egg yolk lecithin demonstrate substantial compositional similarity to breast MFGM in terms of phosphatidylserine and phosphatidylethanolamine profiles.Notably, certain lipid species with relatively low abundance in goat milk MFGM, such as PC(O-20:0/22:0), PE(P-20:0/22:0), Cer(d14:2/22:1)), show relatively high content in soy lecithin or egg yolk lecithin.Furthermore, metabolic pathway analysis indicates that glycerophospholipid metabolism is the predominant phospholipid metabolic pathway across all four sample types. This study elucidates the compositional differences in phospholipids and fatty acids between MFGMs from different milk sources and dietary phospholipids, providing crucial theoretical foundations and empirical data for the humanization of lipid components in goat milk-based infant formula.

Second messenger molecules play an important role in signaling in bacteria in response to changes in the external environment.Cyclic dinucleotides (CDG) are a newly discovered class of second messenger molecules, including c-di-GMP and c-di-AMP, which regulate the physiological functions of bacterial cell wall metabolism, potassium ion homeostasis, biofilm formation, and DNA repair.In order to understand the regulatory mechanism of CDG, this paper reviews the structure and regulatory mechanism of CDG riboswitches, and systematically analyzes the regulatory effect of CDG riboswitches on gene expression, aiming to deepen the understanding of signal transduction mechanism, which provide a reference for the study of the second messenger molecule-mediated signal network regulations.

Sugar is the most important component of honey, constituting approximately 75% of its total composition.Glucose and fructose are the predominant sugars in honey, accounting for 85%-95% of the total sugar content, followed by sucrose which accounts for 1%-5% of the total sugar content, in addition to nearly 30 types of oligosaccharides.These sugar compounds not only serve as essential nutritional constituents of honey but also act as endogenous indicators, playing a significant role in honey classification, adulteration detection, and floral origin authentication.This paper presents a comprehensive review of the analytical methods for sugar profiling in honey, including polarimetry, chemical titration, liquid chromatography (LC), gas chromatography (GC), ion chromatography (IC), and spectroscopy methods, each method has its underlying principles, applicability, advantages, and limitations.By describing the technical characteristics of these approaches, this review seeks to contribute to the refinement and development of analytical methods for honey sugar analysis.

Peanut peptides are deep-processed products of peanut protein, known for their good stability, ability to be directly digested and absorbed by the small intestine, and enhancement of human immunity.Current research on peanut peptides mainly focuses on their antioxidant and antibacterial properties, but they also exhibit excellent metal ion chelation activity.Peanut peptide-metal ion chelates have garnered widespread attention as a new type of metal element supplement.In comparison with inorganic metal ion, peanut peptide-metal ion chelates are considered ideal metal element supplements due to their easier digestion and absorption by the gastrointestinal tract, higher bioavailability, and greater safety.This article reviews the preparation processes and separation-purification methods of peanut-metal ion chelating peptides, analyzes the factors affecting the chelating ability of peanut peptides, further summarizes the chelation mechanism of peanut peptide-metal ions, and also discusses the bioavailability of peanut peptide-metal ion chelates.This article aims to provide theoretical references for the preparation of peanut peptide-metal ion chelates and their application in functional foods and the development of new metal ion supplements.

Neurodegenerative diseases are neurological disorders that seriously affect human health but have no complete cure.In recent years, there has been a great interest in exploring natural compounds that can ameliorate and prevent neurodegenerative diseases.Hericium erinaceus, a valuable edible and medicinal fungus, is not only favored for its unique flavor and nutritional value, but also for its potential medicinal value.Erinacines are cyathane-type diterpenes isolated from the mycelia of H.erinaceus, and have neurotrophic and neuroprotective properties.However, erinacines have not been fully exploited due to imperfect purification and unclear biosynthetic mechanisms.Herein, this review summarized the isolation, biosynthesis and function of erinacines, with the aim of promoting their exploitation and utilization, as well as the high-value development of the H.erinaceus industry.

Polysaccharides, serving as a pivotal constituent in life forms, exhibit diverse biological activities that are intricately tied to their structural configurations.However, their unique structural attributes pose constraints on their utilization in terms of processing and activity.Recently, the modification of natural polysaccharide structures has garnered significant research attention.Among these strategies, carboxymethylation stands out as an efficacious chemical modification approach, capable of markedly enhancing the biological activities and practical applications of polysaccharides.This review delineates the synthetic pathways and characterization methods of carboxymethylated polysaccharides, while also examining the effects of carboxymethylation on the structure and biological activities of polysaccharides, alongside its applications within the food industry and biomedical sector.The objective is to offer a theoretical framework for the research and application of carboxymethylated polysaccharides, thereby fostering advancements in the realm of polysaccharide modification.

The entire process of Baijiu brewing has created a complex and dynamic microecosystem.Microbial interaction is crucial to the regulation of microbial structure and function in the brewing microecosystem, and directly affects the flavor and quality of Baijiu.In recent years, with the development of multi-omics technologies, a large number of studies have analyzed the diversity, function, and succession patterns of microbial communities.However, comprehensive research on the interactions and mechanisms between microorganisms is relatively limited.This paper systematically reviewed the diversity of brewing microorganisms and the functions of core microorganisms in twelve flavor Baijiu, including starter, fermentation, pit mud and yellow water, and comprehensively examined the various interactions between microorganisms.It explored the preliminary application of microbial interactions in strengthening Daqu, improving flavor and regulating quality and safety, aiming to provide a reference for the directional regulation of Baijiu brewing microecology, improving Baijiu flavor and improving Baijiu quality.