Abstract:Bacteria exopolysaccharide （EPS） are high molecular weight biopolymers secreted into the surrounding environment during growth and metabolism. EPSs can enhance the resistance to oxidative stress， dryness and host defense factors， rendering the bacteria additional survival advantages. Bacteria EPSs are widely applied in food， chemical， pharmaceutical， cosmetics and petroleum industries in the form of emulsifiers， gelling agents， thickeners， water-retaining agents， preservatives， stabilizers， etc. Bis-（3'-5'） cyclic di-guanylate acid （c-di-GMP） and cyclic dimeric adenosine 3'-5'-monophosphote， c-di-AMP） are two novel emerging second messengers and can be found in a great many bacteria. Numerous researches show that c-di-GMP and c-di-AMP mediate the signal transduction of various physiological functions， including fatty acid metabolism， potassium ion homeostasis， biofilm and EPSs biosynthesis. This article summarizes and analyzes the metabolism of c-di-GMP and c-di-AMP and the molecular mechanism of EPS biosynthesis mediated by these two message molecules to provide the molecule basis and research directions for signaling network of c-di-GMP and c-di-AMP.

Abstract:In order to predict the structure and B cell liner epitopes of sesame allergen Ses i 3， the bio-information Editseq software of DNAStar， the network server-SOMPA and The BepiPred 1.0 Server were used to predicted the antigenicity， hydrophilicity， surface probability， flexibility and secondary structure. The B-cell prediction epitope was synthetically analyzed. The tertiary structure of Ses i 3 protein was successfully built by homology modeling with SWISS-MODEL and evaluated by the Ramachandran software for stability. Results indicated that B-cell liner epitopes had the high probability in the regions of SESKDP， RQKHQGEHG， NRKSP， QHG， YQREKGRQDDDNPTDPEKQY， RRQG， KYREQQGREGGRGE， EGR， EQGR， RQDR， ENP， RHE， ESK， RPTH， ASQ， SRSRGSYQGETRGRP， ANNNE， SRSQQ， GPRQQQQGR. Homologous modeling with 5e1r.2 as the template successfully constructed the tertiary structure of sesame allergen Ses i 3， and Ramachandran's evaluation showed that the protein model was conformational stable. These results provide a basis for the preparation of specific antibody peptides and the detection of allergens.

Abstract:As a specific spoilage organism of refrigerated fish， Shewanella putrefaciens can survive longer during cold storage due to its strong adaptability to cold and cause the fish spoilage. Cold shock protein （CSP） is one of the key proteins that affects the adaptability of bacteria to low temperature. In the present study， three CSP genes were obtained by PCR amplification， and their structure and function were analyzed by bioinformatics. The results showed that the Csp1589 and Csp1376 of S. putrefaciens shared close homology with Escherichia coli CspA， while Csp2252 was more homology with E. coli CspD； the CSPs were small hydrophilic acidic protein with molecular weight of about 7.4 ku， all of which were located in the cytoplasm and are non-secretory and non-transmembrane proteins. All of them possess specific cold shock domain， and sites and motifs that could bind to single-stranded DNA and RNA. The secondary and tertiary structures of CSPs conformed to the characteristics of CSP family， which contained five reverse parallel β-strands. Three CSPs were functionally predicted to interact with various proteins， including histidine kinase involved in two-component signal transduction system， DNA polymerase involved in DNA replication， chaperone protein htpG， etc. And the possible ligand binding sites of CSP were predicted. It provided some references for further elucidation of the function of CSPs in the process of low temperature adaptation of S. putrefaciens.

Abstract:It is difficult for the bioactive peptides whose sequence lengths are different to establish QSAR （Quantitative structure-activity relationship） model. Although it could be solved by ACCs （Auto and cross auto covariances）， its estimation ability is not satisfactory. Thus， a new method named TTPN （Two-terminal position numbering） was proposed. The principle of TTPN method is to find the shortest length peptide and standardize its number of amino acids， the information of same number amino acid residues of the C-terminus and N-terminus was extracted from database. Then the descriptive variable matrix X and the active data matrix Y were established for QSAR research. In order to verify the effectiveness and application scope of TTPN method， many peptides involve the BT （Bitter peptides）， ACE （Angiotensin I-converting enzyme inhibitor） and antioxidant peptides measured by ORAC （Oxygen radical absorption capacity） were collected. All the results of QSAR showed that TTPN method was better than ACCs to describe the sequence of peptide （R2 and Q2 for TTPN and ACCs are 0.724， 0.329； 0.599， 0.038 in ACE databases respectively）. Furthermore， TTPN could also describe sequences in which information was partially or fully described （R2 and Q2 for 2-14 and 7-14 databases are 0.717， 0.693 and 0.922， 0.753 respectively）. In conclusion， TTPN method not only provides an effective method for the establishment of QSAR model of peptide with distinct length， but also has a better analysis and prediction ability as well as a wider range of applications compared with ACCs method. The explanation of active peptide structure characteristics obtained from the model compared with ACCs method are more precious.

Abstract:To study the inhibitory effect of two antioxidants （phytic acid， L-ascorbyl palmitate） on α-glucosidase， and explore the interaction of the two compounds with the enzyme by molecular docking technique. The IC50 values of phytic acid and L-ascorbyl palmitate for α-glucosidase were （0.207±3.137） mol/L and （0.39±0.00838） mmol/L， respectively. The inhibitory effect of L-ascorbyl palmitate was better. The inhibition types of phytic acid and L-ascorbyl palmitate on α-glucosidase were reversible mixed inhibition and reversible competitive inhibition， respectively. Molecular docking results showed that the two compounds interact well with the amino acid of the α-glucosidase active site. L-ascorbyl palmitate exhibits high efficiency in the inhibition of α-glucosidase and provides a theoretical basis as an enzyme inhibitor. It can reduce the postprandial level of diabetic patients while playing an antioxidant role in food.

Abstract:The amphiphilic polymer can spontaneously form self-aggregating nano-sized micelles having a core-shell structure in aqueous system， which is increasingly attracting attention and recognition for its ability to improve the solubility of hydrophobic substances. In this paper， oat β-glucan was used as raw material， and it was esterified and modified with hydrophobic saturated fatty acid-stearic acid to obtain amphiphilic oat β-glucan ester. By investigating the effect of the amount of stearic acid acyl imidazole added， the reaction temperature and the reaction time on the substitution degree of the product， the substitution degree of the reaction product is the largest， which could reach 0.133， when the stearic acid acyl imidazole amount was 6.50 mL， the reaction temperature was 90 ℃， the reaction time of the whole system was 5.0 hours. The obtained products were characterized by Fourier transform infrared spectroscopy （FTIR） and nuclear magnetic resonance spectroscopy （NMR）. The obtained results all proved the successful preparation of amphiphilic oat β-glucan ester. After studying its related physical properties， further in vitro cytotoxicity test found that oat β-glucan stearate ester （OGE） is not cytotoxic. All the above results suggest that OGE can be used as a new carrier material for hydrophobic bioactive substances， which can effectively solve the current situation of low bioavailability of most hydrophobic active substances. Therefore， it will have broad development prospects in many fields such as medicine， food， and chemical industry.

Abstract:This study investigated the effects of different additions of ferulic acid（FA） and caffeic acid （CA） on the thermomechanical properties of mixed dough， rheological properties， secondary structures， thermal properties and microstructures of gluten proteins. The results showed that the addition of different doses of FA and CA had no significant effects on the water absorption， development time and breakdown viscosity value of the dough， but the stability time reduced and the setback value improved significantly compared with the control group. The addition of FA and CA significantly increased the viscoelastic modulus of the gluten protein， and there was no significant change in the loss tangent of the gluten at 10 Hz. The addition of FA and CA reduced the thermal degradation temperature， thermal denaturation temperature and heat denaturation enthalpy of gluten， and significantly increased weight loss at 600 ℃. The results of gluten protein secondary structure measurement showed that the content of β-sheet and α-helix decreased after the addition of FA and CA. Compared with the control group， the microstructure of gluten became chaotic and disordered with the increase in the amount of FA and CA added.

Abstract:Based on the macrophage and adipocytes co-cultured system， effect of catechins on the gene expression of cytokines and inflammatory enzymes， the phosphorylation levels of AMPK and SIRT1 was studied， and to preliminarily research the anti-inflammatory mechanism of catechin. Catechin with the mass concentrations of 0， 50， 100 μg/mL were added to the four treatments， respectively. The gene expression of cytokines and inflammatory enzymes， phosphorylation levels of AMPK and SIRT1 in adipocytes were determined by quantitative RT-PCR and Western blotting， respectively. Catechin obviously inhibited the gene expression level of pro-inflammatory cytokines （IL-1， IL-6， IL-12） and inflammatory enzymes（iNOS， COX-2）， but promoted the expression of anti-inflammatory cytokines（IL-4， IL-10）. High mass concentration of catechin increased the phosphorylation level of AMPK and SIRT1， it is synergistic between AMPK and SIRT1. In the macrophage and adipocytes co-cultured system， the secretion of TNF-α in macrophages fully induced the differentiation of adipocytes. Catechin has an anti-inflammatory effect by regulating the gene expression of cytokines via AMPK/SIRT1 signaling pathway.

Abstract:Quorum sensing gene luxI/luxR of Aeromonas sobria was used for this study， and the effect of different environmental conditions on the expression of this gene was investigated from the transcription level by real-time fluorescence quantitative PCR to determine the regulatory effect of environmental factors on quorum sensing system. The results showed that the expression level of luxI/luxR gene was the highest at appropriate low temperature （15 ℃） and weak base （pH = 8）， while the expression level of both genes decreased under high osmotic stress. When glucose was the carbon source， the expression of luxI/luxR gene was the highest， and luxI gene was more sensitive to carbon sources than luxR gene. The expression level of luxI gene under different nitrogen sources was as follows： tryptone > ammonium chloride > beef extract > yeast extract > urea， and the expression of luxR gene was as follows： tryptone > ammonium chloride > yeast extract > beef extract > urea. Therefore， the changes of environmental conditions can be used to regulate quorum sensing system in Aeromonas sobria， so as to control its spoilage ability.

Abstract:The present study investigated the 75 molds isolated from Daqu of Shanxi aged vinegar using morphological and ITS sequencing approach. The results showed that Aspergillus niger and Rhizopus oryzae are the dominant bacteria in Daqu， they accounted for 13% and 28% respectively. One excellent strain of Aspergillus niger 186 was screened， with higher glucoamylase of 4 279.11 U/g and cellulase of 476.60 U/g producing ability. The interaction with Aspergillus niger 186 and Rhizopus oryzae 774-2 was investigated. The results showed that when the ratio of Aspergillus niger 186 and Rhizopus oryzae 774-2 was 1∶5， the production of protease and organic acid was significantly higher than that of pure culture of Aspergillus niger 186. Additionally， the ester yield of the co-culture system was also increased by 6.07%. Simultaneously， the variety and content of volatile aroma components were largely enriched. In summary， the characteristics of enzyme and flavor production of different mixed-culture fermentation system were significantly different. It was of great significance to find the optimal combination and proportion of mixed strains to improve the production efficiency and product quality of Shanxi aged vinegar.

Abstract:The aim of this study was to investigate the characteristics of multi-starter fermentation with Chinese indigenous yeast and commercial strains. UCD522K and UCD2610K carrying the kanamycin resistance gene （KanMX） were constructed using commercial S. cerevisiae UCD522 and UCD2610 as the original strains. The fermentation rates and yeast population were not affected by the resistance marker during the fermentations under two levels （55， 433 mg N/L） of yeast assimilable nitrogen （YAN） concentrations. On this basis， the characteristics of mixed fermentation （inoculation ratio 1∶1） with indigenous yeast NX11424 and UCD522K or and UCD2610K were studied respectively. The results showed that compared with pure fermentation， mixed fermentation did not change the fermentation process， and their fermentation rates were not significantly different under high YAN level. The rate of mixed fermentation was between each of pure fermentation under low YAN level. And it was also closer to the fast fermentation strain. The amount of each yeast in the mixed fermentation was influenced by the concentration of YAN. NX11424 continued predominance during the mixed fermentation with UCD522K at high YAN level， while it showed a ratio of 1 ∶ 1 throughout the fermentation under low YAN level. In the mixed fermentation with UCD2610K， the ratio of NX11424 to UCD2610K was maintained at 1 ∶ 1 regardless of YAN concentrations. A kanamycin resistance marker-aided approach with higher screen efficiency was successfully applied in the multi-starter fermentation of wine-like condition in this work， realizing the rapid and sensitive monitor of the number of different S. cerevisiae strains during fermentation. This study also found that indigenous Chinese strain NX11424 could dominate in the wine-making environment with strong fermenting performance and killer commercial yeasts， providing data support for making wines with more particular flavor.

Abstract:In this work， the hop-resistant strain Lactobacillus brevis 49 isolated from the spoiled beer was used as the starting strain to study the extracellular pH， intracellular ATP and chain length， saturation， chain branching， and U/S changes of fatty acids of cell membrane. The results showed that hops had a significant inhibitory effect on Lactobacillus brevis 49， and 60 mg/L was the highest tolerance to hops concentration of Lactobacillus brevis 49. Hops will decrease the extracellular pH of Lactobacillus brevis 49， and high concentration of hops will lead to higher extracellular pH. The amount of intracellular ATP of Lactobacillus brevis 49 under hop stress was an order of magnitude lower than that without hops stress. As the concentration of hops increases， the increase in fatty acid carbon chain length of Lactobacillus brevis 49 cell membrane， especially C20， was much obvious. The average chain length also increases along with the increase of hop concentration； The cyclic fatty acid C19 had a significant increase compared to the control group. When adding the high concentration of hops， the proportion of fatty acid unsaturated fatty acids and branched fatty acids in the cell membrane increases， and the saturated linear fatty acids decreases. Meanwhile， the U/S value also increases together with increase of hop concentration.

Abstract:The natural Jerusalem artichoke inulin was fractionated by ethanol， and the prebiotic activity of different molecular mass inulin was evaluated by simulated digestion environment in vitro， including the proliferation of Lactobacillus plantarum， the rheological properties of fermentation broth and the changes of short-chain fatty acids （SCFA）. The results showed that the proliferation of Lactobacillus plantarum in 10% inulin group was best， the viscosity of fermentation broth was largest， and the content of SCFA was highest. The prebiotic activity of 10% inulin was best than that of natural inulin and 80% inulin. Probiotic microcapsules were prepared by using 10% inulin as wall material to evaluate the stability. The embedding rate， gastrointestinal fluid digestion stability and storage stability of the inulin probiotic microcapsules were determined. The results showed that the microcapsule embedding rate was 71.98%. The dissolution rate was 12% and reaching the maximum after 40 min digestion in artificial simulated gastric juice. The dissolution rate was close to 100% and reaching the maximum in artificial simulated intestinal fluid for 60 min. The storage stability of microcapsules was better than 37 ℃ under the conditions of low temperature 4 ℃ and normal temperature 25 ℃， and the effect was best under 4 ℃ conditions. Therefore， the optimization and application of inulin are conducive to provide a reference for the development of Jerusalem artichoke.

Abstract:Nisin Z produced by Lactococcus lactis K6 from mussels are ribosomal synthesized polypeptides or proteins with antibacterial activity， was combined with several common additives （disodium EDTA， sodium diacetate， sodium citrate， potassium sorbate） and highly antibiotic inhibits foodborne pathogenic bacteria in this study. The minimum inhibitory concentration of nisin Z and 9 antibacterial substances was determined by 96-well plate， and the minimum use amount of nisin Z and several antibacterial substances against food-borne pathogens was determined. Using the checkerboard method to determine the combined inhibitory concentration of nisin Z compounding agent and calculate the fractional inhibition concentration （FIC）， according to the time-killing experiment， further determine synergistic antibacterial effect of the nisin Z compounds against foodborne pathogens in different time. The results showed that the nisin Z compounds did not find significant synergistic antibacterial effect against Gram-positive bacteria （Bacillus cereus， Staphylococcus aureus and Listeria monocytogenes） within 12 h； the inhibitory effect of nisin Z （1.25 BU/mL） In combination with EDTA disodium （0.25 mg/mL） against Salmonella sp. was higher than that of nisin Z alone. The combination of nisin Z （1.25 BU/mL） and polymyxin B （0.1 BU/mL） inhibited Escherichia coli in a synergistic effect within 3 hours， and the synergistic effect was less found after 3 hours.

Abstract:Objective： To study the effect of double protein powder formed by the combination of soy protein isolate and whey protein on hematopoiesis and immune reconstitution in mice after allogeneic hematopoietic stem cell transplantation. Methods： Male BALB/c mice aged 6-8 weeks were randomly divided into normal control group （CON）， hematopoietic stem cell transplantation group （HSCT+NP）， and hematopoietic stem cell transplantation + protein intervention group （HSCT+PP）. Four weeks protein intervention experiment was performed after hematopoietic stem cell transplantation. HSCT+PP group was given a certain amount of double protein suspension， HSCT+NP group was given an equal volume of normal saline， and CON group without any treatment. The blood routine and mouse body weight of each group were measured weekly. The thymus and spleen indexes were measured at the 2nd and 4th week after transplantation， and the content of hematopoietic stem cells in bone marrow and serum biochemical parameters were determined at the time of the 4th week. Results： Compared with HSCT+NP group， the number of peripheral blood leukocytes， red blood cells， platelets and lymphocytes in the protein intervention group （HSCT+PP） recovered significantly faster （P<0.05）， and the bone marrow hematopoietic stem cell content was higher （P>0.05）， thymus index increased significantly （P<0.05）， serum total protein （TP）， immunoglobulin （IgG， IgA， IgM） content was higher， and IgM content was significantly increased （P<0.05）. Conclusion： the supplementation of double protein after hematopoietic stem cell transplantation can accelerate blood cell recovery and immune function reconstruction in mice. Thus， the double protein can be used as a good protein nutritional supplement after hematopoietic stem cell transplantation， which is beneficial to the prognosis of patients.

Abstract:In order to investigate the potential harmfulness of Aflatoxin B1 （AFB1） and T-2 toxin （T-2） contamination in mouldy dried Lutjanus erythopterus and their relationship with intestinal microorganisms， this study used gastric lavage method to infect mice. Illumina-MiSeq high-throughput sequencing technology was used to analyze the changes of microbial community structure and composition， and hematology analyzer was used to determine the erythrocyte， leucocyte and hemoglobin of mice. The activity of two liver enzymes （aspartate aminotransferase and alanine aminotransferase） in mice was determined by enzyme labeling method， and the relationship between the changes of intestinal flora and these potential hazards was analyzed. The results showed that AFB1 significantly increased the relative abundance of Prevotellaceae and Muribaculaceae of Bacteroides， Clostridiales of Firmicutes， and decreased the relative abundance of Lactobacillaceae of Firmicutes and Alcaligenaceae of Proteobacteria， while T-2 significantly increased the abundance of Lactobacillaceae of Firmicutes. However， the abundance of Muribaculaceae and Alcaligenaceae was significantly reduced. The changes of the abundance of these bacteria were confirmed to be associated with hepatitis， blood and immune diseases. AFB1 group significantly reduced the number of leucocyte （P<0.05）， but the number of erythrocyte and hemoglobin did not change significantly （P>0.05）， indicating that AFB1 had immunotoxicity； T-2 group caused three blood indicators of mice to decrease significantly （P<0.05）， indicating that T-2 had strong immunotoxicity and hematotoxicity. The ratio of aspartate aminotransferase （AST） / alanine aminotransferase （ALT） in mice liver of AFB1 group was more than 1， showing obvious hepatitis symptoms， while the ratio of AST / ALT in mice liver of T-2 group was less than 1， and liver injury was not obvious. Abundance changes of intestinal flora caused by AFB1 and T-2 toxin in dried Lutjanus erythopterus were associated with hepatitis， blood toxicity and immunotoxicity， suggesting that the residual harmfulness of AFB1 and T-2 in dried Lutjanus erythopterus might also be associated with mutagenesis of intestinal microorganisms.

Abstract:In order to explore the differences between measured glycemic index （GI） and glycemic load （GL） with predicted values， test meal A1， A2， B and C， each contains 4 whole grains selected from 9 candidate materials were prepared and their GI were tested in 10 healthy subjects and their GL and hydrolysis index （HI） were calculated. Test meal A2， B， C had GI values of 60， 66 and 48， respectively， and the GL value were 23， 23 and 16. However， the test meal A2 prepared with the default cooking program for whole grains resulted higher GI value of 69 and GL value of 26. Neither the estimated GI value from published GI data nor from the in vitro carbohydrate hydrolysis index gave good prediction on test meals containing pulses.

Abstract:The lysozyme in egg white was purified by cation exchange-ultrafiltration， and the purification conditions and enzymatic properties of lysozyme were studied by single factor experiment and Box-Behnken experiment， and its enzymatic properties were discussed. The results showed that when the resin accounts for 24.2% of the volume of egg white solution， NaCl concentration was 1.00 mol/L， the egg white solution pH value of 9.10， the elution time of 62.61 min， it could produce lysozyme with the purity of 96.36% and the activity of 23 718.61 U/mg. The studies of the enzymological properties of lysozyme indicated that it had the highest enzyme activity when pH value was 7.0 and temperature was 60 ℃. In the pH value of 4 to 7， the activity of lysozyme could be well maintained. The thermal stability of lysozyme was good at low temperature while the activity decreased rapidly at a higher temperature. Na+ and Ca2+ had a strong activation effect while K+ had a certain activation on the lysozyme， Mg2+ and Mn2+ had little effects on the lysozyme， Zn2+ had a significant inhibitory effect on the lysozyme. Glycerol， Tween20， Tween40， Tween80 and other surfactants all had inhibitory effect on lysozyme while glycerol had the strongest inhibitory effect. The research results had important value and significance for the industrial purification and production of lysozyme.

Abstract:In order to determine the optimal extraction process of Ganoderma lucidum spore polysaccharide （GLSP）， the ratio of material to liquid， extraction time and extraction temperature were used as the indicators. The yield of polysaccharide extraction was based on the single factor test. The optimum method for extracting polysaccharides from Ganoderma lucidum spores was as follows： extraction temperature 81 ℃， ratio of material to liquid 19：1， extraction time 2 h， under which the extraction yield of Ganoderma lucidum spore polysaccharide was （1.507±0.028）%. Using Ganoderma lucidum spore （GLS） from 7 different sources as raw materials， the Ganoderma lucidum spore polysaccharide was extracted by the best process， derivatized by trifluoroacetic acid hydrolysis and saccharide acetate method， and then gas chromatography-mass spectrometry was used. The monosaccharide composition of Ganoderma lucidum spore polysaccharide was determined by GC-MS. The results showed that the polysaccharides of the seven Ganoderma lucidum spore polysaccharides were similar， consisting mainly of 6 monosaccharides， namely rhamnose， arabinose and xylose， mannose， glucose， galactose， but the content of monosaccharides in different regions was significantly different （P<0.05）， and the average molar ratio was 3.860， 9.829， 11.044， 22.078， 40.338， 14.273. In vitro antioxidant experiments showed that Ganoderma lucidum spore polysaccharide has certain antioxidant capacity， but there were significant differences between different sources. The overall antioxidant performance is S2>S3>S5>S4>S6>S7>S1.

Abstract:In this paper， the conditions for ethyl alcohol production by Saccharomyces cerevisiae Y3401 were optimized， and its aroma-producing characteristics were explored. The ethyl alcohol production conditions were optimized by the single factor step-by-step method and orthogonal experimental design with ethyl alcohol producing medium. Optimum conditions for ethyl alcohol production have been shown as follows： glucose 300 g/L， yeast extract 37.8 g/L， initial pH 5.2， seed age 24 h， the inoculation ratio of 3%， the volume of liquid of 30 mL/250 mL， incubated for 32 h at 30 ℃ and 100 r/min. Under the optimal conditions， the ethanol concentration of Saccharomyces cerevisiae Y3401 was 117.2 g/L， which was increased by 1.24-fold compared with the initial production （52.4 g/L）. Volatile compounds of the yeast in sorghum hydrolysate medium were detected by headspace solid phase microextraction coupled with GC-MS. After culture for 32 h at 30 ℃ and 100 r/min， a total of 40 volatile compounds， such as β-phenylethanol， ethyl acetate， phenylethyl acetate， and so on， which are important to the quality of Baijiu. Therefore， Saccharomyces cerevisiae Y3401 can not only produce high-yield ethanol， but also produce a variety of flavor compounds that can improve the quality of Baijiu. These characteristics of Y3401 are beneficial to its application in Baijiu-making.

Abstract:Ethyl carbamate （EC） is a potential carcinogen present during the fermentation process of rice wine. In this paper， the effects of ornithine carbamoyltransferase （OTC） addition on EC and wine basic quality were studied. Since the OTC can be used to catalyze the degradation of EC precursor citrulline， first the gene is cloned from Lactobacillus brevis， after purifying by Ni-NTA method， added to different stages of rice wine fermentation. The results showed that the OTC which added in the middle of the fermentation can significantly reduce the content of EC， as a result， EC concentration can reduce to 15% at most and affect its main precursors， urea and citrulline， the physicochemical quality of wine was also tested. The results showed there is no significant difference in amino acid， volatile flavor and taste， indicating that the addition of OTC did not affect the product quality， which provided a new direction for the industrial reduction of EC formation.

Abstract:Perilla oil is a natural nutraceutical that can be used as a food supplement and pharmaceutical preparation. Perilla oil is insoluble in water， and it is quite difficult to incorporate it into an aqueous medium， resulting in lower bioavailability. In this study， the HLB value based on surfactant was proposed to guide the preparation of composite surfactant，and combined with a pseudo-ternary phase diagram， the nano-emulsion was prepared by the method of inversion emulsification. The main objective was to optimize the process parameters to form a stable perilla oil nano-emulsion and evaluate its stability. The optimal formula of perilla oil nano-microemulsion was as follows： When the HLB value of Tween80/Span20 was 13， the mass ratio of the compound surfactant and the total oil phase （IPM ∶ perilla oil = 3 ∶ 2） was 8 ∶ 2； when the HLB value of the Tween80/Span20 compound was 14， the mass ratio of the compound surfactant to the total oil phase（IPM ∶ perilla oil = 1 ∶ 1） was 8 ∶ 2； when the HLB value of the EL-40/PEG-400 compound was 13.5， the mass ratio of the compound surfactant to the total oil phase （IPM ∶ perilla oil = 2 ∶ 1） was 7.5 ∶ 1. The particle size， potential and type of the prepared perilla oil microemulsion were analyzed， and the particle size of the stable perilla oil nano-emulsion was mainly distributed at 53.10~69.16 nm， and the potential distribution was -32~-34.6 mV， which further proved that the stability of perilla oil microemulsion was good， and all prepared microemulsion were oil-in-water type. The prepared perilla oil nano-microemulsion was placed in an oven at 37 ℃ for 15 days， and the prepared perilla oil nano-microemulsion had better oxidation stability than the perilla oil.

Abstract:Lactobacillus casei Zhang （L. casei Zhang） and Bifidobacterium animalis subsp. lactis V9 （Bifidobacterium lactis V9， B. lactis V9） are probiotics that were isolated and developed in China， and they exhibited desirable properties. Yogurt is one of the best carriers for probiotics. This study characterized the content of extracellular polysaccharide （EPS） in yogurt fermented by L. casei Zhang and/or B. lactis V9 for the first time. The rheological properties of yogurt were studied by multi-frequency diffusion spectroscopy. The texture parameters of yogurt， like firmness， cohesiveness， consistency， and viscosity index， were measured. The viable counts of the probiotic strains and their stability during storage were analyzed. The results showed that the increase in EPS content was significantly higher for the probiotic groups compared with the control group， increased from （546.3±31.5）， （361.1±20.1）， （515.2±17.5） mg/L to （1 165.4±37.8）， （903.6±33.9）， （1 103.8±45.6） mg/L for groups containing B. lactis Zhang alone， B. lactis V9 alone， and a combination of both bacteria， respectively， contrasting to an increase from （64.4±5.4） mg/L at the beginning to （351.6±5.4） mg/L at the end of storage （P<0.05 for the control group）. The application of L. casei Zhang group resulted in high elastic index and low solid liquid balance rheological properties， enhancing the strength of the gel structure. The levels of firmness and viscosity index were associated with the EPS content in yogurt. Adding L. casei Zhang （including single and compound） significantly increased the consistency， firmness， cohesiveness， and viscosity index of yogurt. Adding B. lactis V9 only increased the firmness and viscosity index. In addition， there was no difference in the degree of acidification of yogurt between different groups （P > 0.05）. Furthermore， L. casei Zhang and B. lactis V9 were stable during storage with >108 CFU/mL， which ensures the probiotic effect of yogurt. In conclusion， adding probiotic L. casei Zhang and/or B. lactis V9 to yogurt does not only maintain the probiotic effect of the yogurt， but also improve the texture characteristics and storage stability. Data provided by this work will serve as technical references for production and industrialization of these products. This study also provides insights into methodology development and evaluation for fermentation and storage of probiotic yogurt.

Abstract:The application of three different strains of Streptococcus thermophiles strains co-cultivation with Lactobacillus bulgaricus ND02 on gelation process during milk fermentations has been investigated using rheological technology. Meanwhile， to screen one Streptococcus thermophiles strain with excellent fermentation properties， viscosity， acidity and the number of viable cells were evaluated during fermentation and storage. The results showed that the viscosity and acidity between the three fermented milk samples was significantly different during fermentation and storage （P<0.05）， while the number of viable cells was higher than 1×106 CFU/mL. The three different strains of Streptococcus thermophilus had different effects on gelation process during milk fermentation. The Streptococcus thermophiles GW21-4 could improve the quality of yogurt and enhance gel structure. In summary， the Streptococcus thermophilus GW21-4 has the potential to be used as a starter culture for milk fermentation.

Abstract:Methods： The Lactobacillus plantarum X19-2D with strong protein decomposition ability were inoculated into mutton fermented sausages， and natural fermentation and inoculation of commercial starters were used as controls. Study changes on amino nitrogen， free amino acids， protein content and volatile salt-based nitrogen（TVB-N） in fermented sausages. Objective： Study the effects of Lactobacillus plantarum on protein decomposition and free amino acids released in fermented sausages. Results： In 11 days and 90 days of storage， the contents of amino nitrogen in the X19-2D group was significantly higher than natural fermented group （P<0.05）. During the storage period， the contents of total free amino acids and flavor amino acids in the X19-2D group were higher than those of the other two groups， and essential amino acid pattern is closer to nutritional recommendations than the other two groups. There was no significant difference on protein content between 3 groups of sausages （P>0.05）. In addition， in 11 days and 90 days of storage， the TVB-N contents of the X19-2D group was significantly lower than other two groups （P<0.05）. Conclusion： The L. plantarum X19-2D can promote mutton fermented sausage protein decomposition and non-volatile flavor production， amino acid composition is more beneficial to human absorption， and can improve product safety to some extent.

Abstract:In order to comprehensively utilize the crayfish shell and reduce the production cost of chitin deacetylase， in this study we used crayfish shell powder as the main component of the medium， and inoculated with Rhodococcus sp. strain 11-3 to produce chitin deacetylase. The crayfish shell powder was firstly proteolytically hydrolyzed； then， supplemental nutrients and environmental conditions were optimized by single factor test， Plackett-Burman design， steepest climbing test and Box-Behnken test. The results showed that 19% crayfish shell powder medium was treated with alkaline protease at 5 U/mg for 4 h， supplemented with 1% sucrose， 0.25% ammonium sulphate and 0.75% corn syrup. Rhodococcus was introduced into the medium at a seeding rate of 3%， and cultured at 200 r/min for 2.5 days. The enzyme production activity reached 2 723 U/mL， which was about 53 times higher than the initial crayfish shell powder medium. Therefore， Rhodococcus in the obtained medium having crayfish shell powder as a main component can produce chitin deacetylase having high enzyme activity. It provides a new way for the comprehensive utilization of crayfish shells， and also provides a research basis for the future direct extraction of chitosan from crayfish shells using biological methods.

Abstract:Mussel cooking liquid is rich in macromolecular nutrients such as sugars and proteins and other functional ingredients. However， mussels' strong enrichment ability and environmental influence make it accumulate heavy metals such as cadmium in the body. Thus， it makes the mussel cooking liquid such high cadmium content that it affects the reuse of mussel cooking liquor to a certain extent. In this paper， mussel cooking liquid was used as the research object， and the optimal process conditions for reducing the content of heavy metal cadmium in mussel cooking liquid by ferrite method were discussed. Based on the reduction of cadmium content， protein retention rate and total sugar retention rate in mussel cooking liquor， the quadratic orthogonal design and response surface analysis were carried out by three factors： pH value， addition of FeSO4 and reaction temperature. The optimal ferrite method for reducing cadmium was obtained. The results showed that pH value and temperature had significant effects on cadmium reduction. pH value had significant effect on protein retention rate and total sugar retention rate. After SAS response surface analysis， when pH was 8.0 and reaction temperature was 90 ℃， the addition of FeSO4 was 447 mg/70 mL， the effect of reducing the cadmium content by ferrite method was the best.

Abstract:In order to avoid secondary pollution， in actual production， products are usually pre-packaged for RF treatment. Therefore， it is particularly important to study the influence of RF treatment on the inner and outer packaging materials. In this paper， pepper powder as Installation， EVOH/PA film as external packaging material， using 6 kW， 27.12 MHz RF equipment for sterilization， the key factors affecting the heating rate in the RF process were studied. It was found that with the increase of electrode gap， the electric field strength and the RF output power decreases， so the heating rate of the packaging decreases. With the increase of the moisture content of the pepper powder the dielectric loss factor increases， so the heating rate of the packaging decreases. The total number of colonies at different temperature and the pepper powder's color with the optimal sterilization temperature were studied. The results showed that when the temperature of RF treatment reached 80 ℃， it had almost no bacteria detected. Moreover， this temperature had no significant effect on its color. The effects of RF treatment on the external packaging materials were studied. The results showed that the mechanical and barrier properties of EVOH/PA packaging films were not significantly affected by RF treatment. Therefore， RF treatment can be used as a new and effective sterilization method of pre-packaged pepper powder.

Abstract:The changes of biogenic amines in Illexargentinus were determined by high performance liquid chromatography （HPLC） at different storage temperatures. The main characteristics of biogenic amines were determined and their freshness was evaluated. The amine-producing bacteria were isolated and identified. The results showed that the main biogenic amines produced in Illexargentinus were phenethylamine， putrescine， cadaverine and tyramine. Histamine， spermine and spermidine did not change significantly during storage. The TBA and TCA indexes in Illexargentinusat at different storage temperatures with the prolongation of storage time were increasing， while the pH value decreased first and then increased. Amine strains A1-A11 and B1-B12 were isolated under storage conditions of 25 ℃ and 4 ℃， among which 16 strains of saprophyte， 16 strains of cadaverine， 14 strains of histamine and 2 strains of tyramine were isolated. 5 strains （Citrobacter freundii， Citrobacter murliniae， Citrobacter braakii）， 2 strains （Hafnia alvei）， 1 strain （Pantoea agglomerans）， 1 strain （Obesumbacterium proteus）， 1 strain （Kluyvera cryocrescens） and 1 strain （Klebsiella aerogenes） were screened under the condition of 25 ℃. 1 strain of Enterobacteriaceae bacterium， 1 strain of Citrobacter braakii， 1 strain of Klebsiella aerogenes， 3 strains of Obesumbacterium proteus， 6 strains （Hafnia alvei， Hafnia alvei sensu， Hafnia paralvei） were screened under the storage condition of 4 ℃.

Abstract:Fresh mackerel were stored in the refrigerated sea water system. The bacterial composition and changes during storage were studied by selective medium and 16S rDNA sequence analysis. Moreover， the dominant spoilage bacteria in the spoilage samples were identified and the specific spoilage bacteria were determined by the potential spoilage ability tests. The results showed that the dominant bacteria changed from Psychrobacter sp. to Pseudomonas sp. and then to Shewanella sp. during the storage. Shewanella sp.， Enterobacter sp. and Citrobacterfreundii were the dominant bacteria in the spoilage samples. The results of the potential spoilage ability tests indicated Shewanella sp. made more contribution to the increase of TVB-N， TMA and TVC while Citrobacterfreundii contributed more to the accumulation of histamine. Yet， TVC in the samples incubated with Citrobacterfreundii were kept at low level. Therefore， Shewanella sp. was identified as the specific spoilage bacterium of mackerel stored in the refrigerated sea water system.

Abstract:Objective： A strain of Lactococcus lactis subsp. lactis， named as IMAU11823， was isolated from natural fermented dairy products Jiaokou in Xilin Gol League of Inner Mongolia， which expressed excellent fermentation characteristics and capacity of exopolysaccharide（EPS） production. In this present study， whole genome sequencing of this strain was performed to analyze the mechanisms of EPS production. Methods： The genome of this strain was generated by the PacBio SMRT sequencing technique， then the assembly， prediction and annotation of the genome were carried out in a series of bioinformatics methods. The genes related to the EPS biosynthesis were furtherly explored. Results： In the strain L. lactis subsp. lactis IMAU11823， a single circular chromosome （2 458 520 bp） and three circular plasmids （127 965， 24 554， 7 734 bp） were detected. The GC content of the genome and plasmids were 35.2%， 35.7%， 39.5% and 32.7%， respectively. Furtherly， genes associated with the transport system of lactose， cellobiose， sucrose， fructose， mannose and galactose， as well as biosynthesis of seven sugar nucleotides were annotated in IMAU11823 genome. Besides， an eps gene cluster epsRXCDBEF （GTF1） H （GTF2） JKM involved in EPS biosynthesis was also predicted. Conclusion： The present study revealed the genomic characteristics and the potential mechanisms for the EPS synthesis of L. lactis subsp. lactis IMAU11823， which could provide a theoretical basis for the structural characteristics of EPS and laying a theoretical foundation for the strain in the industrial application.

Abstract:Objective： One hundred and eighteen foodborne Salmonella isolates that previously recovered from 7 provinces （cities）， which including Shaanxi， Guangdong， Fujian， Shanghai， Beijing， Henan and Sichuan， were reidentified and characterized via Gram staining morphology， biochemical characterization， 16S rDNA gene sequencing； antimicrobial susceptibility； the genetic stability of β-lactam antibiotic resistance encoding genes of 12 representative isolates； for reference strain preparation for β-lactam antibiotic resistance encoding gene detection among foodborne pathogens. Methods： To reidentify the isolate， Gram stain， VITEK biochemical and MALDI-TOF MS identification， and 16S rDNA gene amplification and sequence analysis were used. The antibiotic susceptibility was tested via agar dilution method issued by the Clinical and Laboratory Standards Institute. The genetic stability of β-lactam antibiotic resistance encoding genes was determined using subculture， PCR， DNA sequencing and online BLAST software of the GenBank database. Results： The biochemical characteristics， sequence of 16S rDNA， flight mass spectrometry of proteins of 118 Salmonella were consistent with those of typical Salmonella. Among 118 Salmonella isolates， antibiotic resistance was commonly found to ampicillin （100.00%）， sulfisoxazole （100.00%） and ceftiofur （100.00%）； more than 50% of the isolates resisted to 7 kinds of antibiotics. blaTEM-1 （64.41%） was most frequently detected among the isolates， the detection rates of blaCTX-M-55， blaOXA-1， blaCTX-M-3， blaCTX-M-15， blaTEM-116， blaCTX-M-123 and blaCTX-M-64 positive isolates were 50.85%， 16.10%， 15.25%， 1.69%， 1.69%， 0.85% and 0.85%， respectively. No loss or mutation was detected among the base or gene fragment of β-lactam antibiotic resistance encoding genes of the 12 screened representative Salmonella isolates during subcultures. Conclusion： Results of 4 different identifications consisted to those of the typical Salmonella should to be； the antibiotic resistance encoding genes blaTEM-1， blaCTX-Ms and blaOXA-1 carried by the isolates could be stably inherited during subculture， the 12 representative Salmonella were verified to have the potentiality to produce reference strain for β-lactam antibiotic resistance encoding gene detection.

Abstract:Jinzhou side dish is popular among people in Liaoning Province， and it is rich in lactic acid bacteria and yeast. 20 yeast strains from 44 Jinzhou side dishes were isolated in this study. Five excellent yeast strains （HG2， HD3， LJ1， SJ4 and SJ5） were initially screened by comparison of acid-tolerant and bile-tolerant capacity， and analysis of fermentation characteristics such as salt tolerance， gas production， calving and alcohol production. They were rescreened by using sugar capacity， flavor-producing ability， and protein-breaking ability， and finally two yeast strains （HD3 and SJ4） with higher reducing sugar consumption rate， flavor-producing ability and protein-breaking ability were obtained. After morphological identification， physiological and biochemical tests， and combined with 26S rDNA identification， the strain HD3 was Pichia fermentants， and the strain SJ4 was Torulaspora delbrueckii. This study provides a foundation for the development and application of excellent yeast starters.

Abstract:Objective： Streptococcus thermophilus is a kind of beneficial bacteria with obvious therapeutic effect on human body. In this experiment， 442 strains of S. thermophilus isolated from traditional fermented dairy products as research objects to screen out a high-yield extracellular polysaccharide strain MGD1-4 and the extracellular polysaccharide was isolated， purified and analyzed structurally. Methods： A few single fractions were purified from the extracellular polysaccharide produced by the fermentation broth of the strain， using the method of anionic chromatography of DEAE-Cellulose 52 and Sepharose CL-6B. And the structure was analyzed by gel permeation chromatography （GPC）， high performance liquid chromatography （HPLC）， infrared spectroscopy （IR） and nuclear magnetic resonance （NMR）. Results： It found that EPS-1a was a neutral polysaccharide with a molecular mass of 1.572×105 u， EPS-3a was an acidic polysaccharide with a molecular mass of 3.825×105 u， and both of them were single polysaccharide. The results of monosaccharide composition indicated that EPS-1a was mainly composed of glucose， mannose and galactose. The molar ratio of three was 3.62∶1∶2.99 and accounting for more than 90%， but EPS-3a was mainly composed of mannose， galactose and arabinose， which accounts for 80.6% of total， its molar ratio was 1.19∶1∶1.08. Combined with the results of 1D NMR， it was showing that the sugar ring of EPS-1a and EPS-3a were all pyranose rings， containing α glycosidic bond. Conclusion： By analyzing the structure of extracellular polysaccharide produced by the strain， the physical and chemical properties were initially determined， which is of great significance for further study of the structure-activity relationship of extracellular polysaccharide.

Abstract:In this study， three and one strain of bacteria were isolated from prawn sauce and fish sauce， respectively， and were identified as Hafnia alvei strains by 16S rRNA sequencing， physiological and biochemical methods. To investigate the spoilage characteristics of H. alvei to seafood， the four isolated strains and another two H. alvei strains isolated from spoiled instant sea cucumber and Turbot were used to measure their phenotypes of biofilm formation， swimming motility， salt resistance， drug resistance， TVB-N and biogenic amine production. Results achieved shown that the six strains could form biofilms， and halos were found in the swimming plates which indicated the swimming motility of H. alvei strains. Tolerance to salt of the six H. alvei strains reach to 0.05 g/mL， in addition， resistance against drugs of ampicillin， spectinomycin， sulfamethazine and sulfadiazine was found in H. alvei， however， they are sensitive to gentamicin， tetracycline， chloramphenicol， kanamycin， ofloxacin， ciprofloxacin and furazolidone. The TVB-N values caused by the six H. alvei strains increased with prolong of storage time. Besides， all the tested strains could secret three kinds of biogenic amine （putrescine， cadaverine and histamine）， and produced more putrescine and cadaverine than histamine. In a word， H. alvei strains were approved the ability to cause food spoilage， and this study is of great significance in exploring the spoilage of seafood caused by H. alvei.

Abstract:In this study， yeasts were purified from traditional shrimp paste by gradient dilution method and their carbon source utilization ability were studied. After extraction of genomic DNA and PCR amplification， 26S rDNA sequence analysis for these yeasts were carried out. Four kinds of yeasts were identified， which were Rhodotorula mucilaginosa， Candida parapsilosis， Trichosporon domesticum and Debaryomyces hansenii， respectively. Carbon source utilization was evaluated with carbon source assimilation analysis. Results showed that the utilization ability of carbon source from strong to weak was as follow： glucose = sucrose> glucosamine> sorbitol> glycerol> mannitol> citric acid> lactose> chitosan. Glucose and sucrose were the optimal carbon sources， which can support the growth of all yeasts. Glucose and sucrose can support all yeast growth， and the remaining carbon sources can support yeast growth to varying degrees. This study provides the microbial resource from shrimp paste.

Abstract:In order to excavate the beneficial microorganism resources in salted pepper and further improve the quality control of salted vegetables. The community composition and relative abundance in the salted pepper were explored by 454 pyrosequencing technology. The results showed that fungi with known classification status in salted C. annuum L. var. dactylus M could be assigned to 2 phyla， 13 classes， 17 orders， 31 families， 45 genera and 87 species. Fungi with known classification status in salted C. annuum L. var. conoides Irish could be assigned to 1 phyla， 1 class， 2 orders， 2 families， 2 genera， and 1 species. The dominant phyla in salted C. annuum L. var. dactylus M were Ascomycota （73.63%） and Basidiomycota （23.42%）. Ascomycota （99.96%） was the only phylum with known classification status in salted C. annuum L. var. conoides Irish. The dominant genera in salted C. annuum L. var. dactylus M were Pichia （25.78%）， Alternaria （21.85%）， Hannaella （10.5%）， Candida （7.82%）， Cryptococcus （6.92%） and Cladosporium （6.27%）. The dominant genera in salted C. annuum L. var. conoides Irish was Candida （93.49%）. The microbial diversity of salted line pepper and salted rice pepper was significantly different， and the microbial diversity index of salted line pepper was higher than that of salted rice pepper.

Abstract:By inoculating whey and compound fermentation （Staphylococcus xylose， Staphylococcus aureus， Pediococcus pentosaceus and Lactobacillus plantarum ratio： 1 ∶ 1 ∶ 2 ∶ 1）， the experiment was divided into compound fermentation group， a whey group， whey + starter group， and control by natural fermentation， the effect of different starter cultures on nitrite， nitrosamine residue and flavor formation in mutton jerky was explored. The results showed that the nitrite content （1.86 mg/kg） and nitrosamine content （110.61 μg/kg） in the whey group were significantly lower than the other three groups （P<0.05）， indicating that whey can reduce the residue of nitrite and nitrosamine. Totally 22 kinds of flavor substances were detected in the whey + starter group， which were higher than 21 kinds in the control group； the relative content of the flavor substances was also significantly higher than that of the control group and the whey group. The presence of nitrite produces some alcohols （such as 1-octene-3-ol， linalool）， but it inhibits the production of aldehydes and has less effect on ketones and other substances. Therefore， whey can reduce the residual amount of nitrite and nitrosamine in jerky， and improve the safety and flavor sensory quality of jerky.

Abstract:Evolution of the odor-active volatile compounds of Pixian-douban and its aroma characteristics during different fermentation phases were analyzed by gas chromatography-mass spectrometry （GC-MS）， gas chromatography-olfactometry （GC-O） and quantitative descriptive sensory analysis in this study. The results showed that 36 odor-active volatiles were identified in Pixian-douban， which endowed the product with many aroma characteristics like alcohol， sour， floral， fruity， caramel-like， burnt， miso-flavor and pungent. Furthermore， partial least squares regression model （PLSR） was used to correlate those aroma characteristics with odor-active volatiles. The results showed that alcohol had the strongest correlation with 2-methyl-1-butanol， sour was closely related to acetic acid， floral mainly came from benzene acetaldehyde and phenylethyl alcohol， fruity was correlated with ethyl acetate， ethyl isovalerate， 2-methylbutyric acid and benzene acetaldehyde， miso-flavor was mainly related to 3-methylthiopropanal， furfural and tetramethylpyrazine， while caramel-like might be formed by 2-methylbutyraldehyde， guaiacol， ethyl benzoate， HDMF and HEMF. The research could provide some theoretical information for improving the aroma characteristics of Pixian-douban.

Abstract:Sour yak milk， Tibetan mushroom Yogurt and Qula are traditional dairy products made by Tibetans in Gansu Tibetan areas， the bacterial communities contained in them play an important role in their quality. This paper took traditional yak fermented dairy products produced by different Tibetan families in Tibetan areas of Gansu as the research objects. The Illumina MiSeq high-throughput sequencing platform was used to study the diversity and community structure of bacteria in three major categories of nine traditional dairy products， correlation analysis of bacterial community distribution combined with different samples. Finally， 511 070 high-quality 16S rRNA gene sequences were obtained， a total of 5 bacterial gates were identified， 11 different bacterial genus. Among them： Firmicutes and Proteobacteria are dominant bacteria gates， Lactobacillus and Streptococcus are high abundance genus in various samples， followed by Macrococcus and Lactococcus. Different types of traditional yak fermented dairy products had different bacterial communities. The function of PICRUSt indicate that basically functional prediction dominates. The results of this thesis could provide the necessary theoretical basis for the study and protection of excellent bacteria in traditional yak fermented milk in Tibetan areas of Gansu.

Abstract:Small molecular fatty acid esters are one kind of important volatile flavor component with aromatic odor. They are widely found in the traditional fermented foods and have significant influence on food sense and flavor. Microbial originated functional enzymes are important tools for the synthesis of small molecular fatty acid esters. The microorganisms derived from traditional fermented foods are diverse， and the functional enzymes that catalyze the synthesis of small molecular fatty acid esters carried by these species also show polymorphism. Studies have shown that the microorganisms with small molecular fatty acid ester synthesis capabilities include bacteria， molds and yeasts. The enzymes that catalyze ester synthesis are mainly derived from the α/β hydrolase family， with lipases and esterases as the representatives. Enzymes provide a green route for the synthesis of esters and contribute to the application of small molecule fatty acid esters in the food industry. Meanwhile， the enzymatic synthesis of esters also promotes the use of small molecular fatty acid esters in the areas of pharmaceuticals and fine chemicals. This work summarizes the diversity， status and further development of microorganisms and enzymes for fatty acid ester synthesis from traditional fermented food.

Abstract:Metabolic disorders caused by obesity can lead to a series of metabolic diseases， such as hypertension， hyperlipidemia， diabetes and so on. They also increase the risk of neurological diseases， such as cerebral infarction and cerebral hemorrhage. Serious cases can lead to death. With the wide application of microbial macrogenomics， transcriptome and other new technologies such as high-throughput sequencing in the study of intestinal microorganisms in obese people， the relationship between intestinal microorganisms and obesity and its regulatory mechanism have gradually been recognized. Studies have shown that regulating intestinal microorganisms in obese people can improve fat storage and intestinal mucosal permeability， thereby alleviating the body's obesity symptoms. In recent years， it has been found that intestinal microorganisms with regulating effect on obesity may play an important role in the next generation of probiotics such as Bacillus mimetica and Ackermania besides Lactobacillus and Bifidobacterium， which are traditional concepts. This paper reviews the recent studies on obesity， intestinal microflora， next generation probiotics and their effects on fertilizer by scholars at home and abroad. The latest research progress and development trend in the regulation mechanism of obesity are expected to provide reference for further accelerating the research and application of next generation probiotics to intervene and improve the occurrence and development of obesity and improve human health.

Abstract:Milk and dairy product allergies are the most common food allergies in infants. In recent years， the prevalence of milk allergies has increased rapidly. Dairy product allergy refers to the immune response of a series of clinical symptoms caused by human ingestion of allergen ingredients， resulting in tissue or organ damage. Milk allergy seriously affects the quality of life of patients and their families， even more so than chronic childhood diseases. Although protein hydrolysates of different formulas are used clinically to replace cow milk， nutritional problems such as the bitterness of hydrolyzed protein infant formula powder and the slow growth of infants are still unresolved. At present， avoiding the use of cow milk and its products is a reliable solution to milk allergy. However， infants and children who do not consume milk protein can lead to malnutrition and slow growth. It is imminent to solve the problem of allergens in dairy products. Studies have reported fermentation and thermal processing， Physical processing （such as high-pressure dynamic micro-jet） and proteolysis are effective ways to desensitize. At present， the research on the function of probiotics is a hot spot in the food and medicine fields， and lactic acid bacteria fermentation may be an important trend and means. This article focuses on the research status of lactic acid bacteria fermentation to reduce milk protein allergies， summarizes the molecular characteristics of allergens in milk， allergy detection methods， etc.， explores the research methods of reducing allergenicity， and provides a certain reference for the research and development of hypoallergenic milk products.

Abstract:During processing and storage of meat and meat products， improper handling will cause bacterial contamination with further the formation of bacterial biofilm and therefore the corruption and pathogenicity of meat products. Biofilm， a microbial community with three-dimensional structure， is a special growth mode for microorganisms to resist the adverse external environment. It can improve the adverse environment and the influence of bacteriostatic agents on microorganisms. Pathogenic bacteria and spoilage bacteria can both produce biofilms， which lead to great harm to the meat processing industry. In this paper， the mechanism， influence and prevention and control measures of bacterial biofilm formation in meat food in recent five years were discussed， aiming to provide theoretical foundation and practical application for the formation and prevention of various bacterial biofilms.

Abstract:The coatings are a safe， non-toxic and effective way of food processing， its application in food preservation has been relatively mature. In recent years， edible coatings increase gradually in the application of deep-fat fried foods because of the efficient way of blocking oil absorption and moisture to offshoring， so it has a unique advantage in water retention and reducing oil absorption. Compared with polysaccharides and plant protein coatings， animal proteins have the advantages of avoiding allergies， high nutritional value， good mechanical properties and increasing the added value of by-products， and have shown a tendency to replace the formers. In this paper， the application of edible animal protein coatings to inhibit oil absorption in deep fried foods was introduced， and the mechanism of inhibiting oil absorption was described in detail.