Abstract:Food sensory perception is the important foundation for future food personalization needs and intelligent manufacturing. Food umami perception is based on multidisciplinary approaches such as psychology， physics， chemistry， physiology， neuroscience and food science， revealing how human sense， process， recognize and understand umami taste stimuli through visual， olfactory， gustatory， tactile and auditory means， and generate different motivations and emotions. This article discussed the definition of food perception， and outlined the importance and influencing factors of food perception. Then food umami perception was taken as an example， whose material and physiological basis， and evaluation methods were expounded. Finally， the future development trend of food umami perception was prospected， and hoping to provide references for food flavor and sensory science related research and future food development.

Abstract:Static digestion mode in vitro was used to digest egg ovotransferrin by the simulated gastric juice， small intestine fluid and small intestinal brush border membrane enzyme in infants and adults， respectively. Tricine-SDS-PAGE and MALDI-TOF-MS were used to analyze the digestion products at all stages to define the digestibility of ovotransferrin. It was shown that ovotransferrin could be digested by the simulated gastric juice， small intestine fluid and small intestinal brush border membrane enzyme in infants and adults. Regarding to the digestion in simulated gastrointestinal fluids in infants， the molecular weight of gastric digestion products were 5-15 ku and 30-50 ku. The small intestinal digestion products were 0.5-10 ku. At last， 0.5-0.7 ku peptides were produced by small intestinal brush border membrane enzyme. The molecular weight of the digested ovotransferrin by the simulated gastric fluid in adult was the same as that of infants， while 0.5-0.8 ku peptides were mainly produced in intestinal digestion. However， only 0.5-0.7 ku peptides were generated after further digestion by small intestinal brush border membrane enzyme. This work preliminarily defined the characteristics of in vitro gastrointestinal digestion of ovotransferrin， providing some experimental support for better understanding that ovotransferrin is more likely to cause egg allergy in infants.

Abstract:Objective： The effects of different molecular weight Auricularia auricular fermentation products on glucose lipid metabolism of HepG2 cells were evaluated by establishing HepG2 cell fat accumulation model and normal HepG2 cell model. The effects and differences of glucose lipid metabolism in different molecular weights of A. auricular were revealed. Methods： The supernatant of A. auricular fermentation was divided into 0-10， 10-50， 50-100， 100-300 ku and >300 ku by ultrafiltration centrifuge tube， and the fermentation products of A. auricular was obtained by constant temperature drying. The HepG2 cell fat accumulation model and the normal HepG2 cell model was established. And the effects of different molecular weights fermentation products of A. auricular on glucose lipid metabolism were evaluated by thiazolyl staining absorbance （MTT value）， oil red O staining， triglyceride （TG） value， total cholesterol （TC） value， lipoprotein lipase （LPL）， Hepatic lipase （HL） activity， glucose content， hepatic glycogen content and hexokinase （HK） activity. Results： The fermentation products of A. auricular can regulate the glucose lipid metabolism of HepG2 cells， reduce cell fat accumulation and glucose content， and increase the activity of fat metabolism enzyme and sugar metabolism enzyme. Among them， the effects of 100-300 ku and >300 ku A. auricular fermentation products were more obvious. Conclusion： The fermentation products of A. auricular can regulate glucose lipid metabolism in HepG2 cells， and the effects of 100-300 ku and >300 ku A. auricular fermentation products are more obvious.

Abstract:In this study， human hepatoma cells （HepG2） were treated with α-LA-OA， bovine-α-lactalbumin （α-LA） and the control solution. The effects of α-LA-OA on glycolysis and mitochondrial aerobic respiration were evaluated by the Seahorse Flux. These results indicated that α-LA-OA significantly reduced the glycolysis ability and mitochondrial aerobic respiration ability of HepG2， as well as the ATP levels （P<0.05），whereas α-LA and the control solution did not exhibit the above effects （P>0.05）. This study laid a theoretical basis for the development of tumor-targeted drugs.

Abstract:In order to explore the absorption mechanism of soybean peptides with the biological activity， 22-NBD cholesterol micelle incubated Caco-2 cells were used as a high cholesterol model. Effects of three kinds of soybean peptides VAWWMY（VY - 6）， LPYPR （LR - 5）， and WGAPSL （WL - 6） on the cholesterol dissolution inhibition rate， absorb cholesterol capacity， and cholesterol transport were investigated. Results indicated that WL-6 had the highest cholesterol dissolution inhibition rate at 0.5 mmol/L concentration. However， the inhibition rate gradually decreased with the increasing concentrations. WL-6 could inhibit 14.2% of cholesterol uptaking by cells at the concentration of 2 mmol/L. For the cholesterol absorbing capacity， VY-6 and WL-6 had the best inhibition rate of 43.1% and 45.95% at the concentration of 2 mmol/L， respectively. LR-5 had the best inhibition absorbing rate of 45.7% at the concentration of 2.5 mmol/L， which indicated that WL-6 had the best cholesterol absorbing capacity and higher than simvastatin. In the experiment of cholesterol transport， WL-6 had the best inhibition rate of 30.7% at the concentration of 2 mmol/L. Above all， WL-6 had the best power at cholesterol lowering effect.

Abstract:DPPH and ABTS antioxidant experiments were used to evaluate the antioxidant activity of single and mixed agricultural product extract （mulberry， blueberry and sweet potato）. The experimental results were plotted according to different proportions of different agricultural products， and the differences in antioxidant interactions caused by the mixture of extracts and proportions of different agricultural products were analyzed by isoradiation analysis method. Results showed that in DPPH antioxidant scavenging experiment， the optimal antioxidant capacity product was blueberry extract followed by the mulberry extract and the sweet potato extract. And in the same model， the mulberry extract and sweet potato extract were mixed at a ratio of 15∶5 to achieve the optimal antioxidant capacity. In the ABTS antioxidant scavenging experiment， the best antioxidant capacity product was mulberry extract followed by the blueberry extract and the sweet potato extract. And the mulberry extract and sweet potato extract were mixed at a ratio of 9∶11 to achieve the best antioxidant capacity. Among the combination of agricultural products， the combination of lipophilic-hydrophilic extracts showed the highest synergistic antioxidant effects.

Abstract:This paper mainly studied the adsorption characteristics of lead-tolerant E. hirae Qaa of lactic acid bacteria that has been isolated and identified. E. hirae Qaa strains was used in the lead adsorption experiments which were conducted to investigate the effects of factors pH， adsorption temperature， adsorption time， cell mass concentration and lead initial ion mass concentration on lead adsorption efficiency. The optimal adsorption condition of E. hirae Qaa strains was explored by response surface method. The optimal adsorption conditions of E. hirae Qaa adsorption lead were obtained with 8.24 mg/g at adsorption time was 230 min， wet cell mass concentration was 6 g/L， Pb2+ mass concentration was 80 mg/L， pH value was 5.6.

Abstract:In this paper， the antimicrobial activity of fermentation supernatant and bacteriocin produced by Lactobacillus salivarius O2A against Salmonella was studied. The effect of metal ions-bacteriocin against Salmonella and its mechanism were investigated. Alone bacteriocin and metal ions-bacteriocin had good bacteriostatic effects on Salmonella. The growth curve of different antimicrobial agents on Salmonella changed greatly after treatment for 18 h， and the bacteriostatic effects was better in the Zn2+（30 mmol/L） - fermentation supernatant and Zn2+（30 mmol/L） -bacteriocin. Compared with the standard Salmonella strain， the results of scanning electron microscope and transmission electron microscope show that the micromorphology of the treated strain was destroyed to varying degrees， among which the most serious damage was caused by the Zn2+（30 mmol/L） -bacteriocin. The mechanism of bacteriostasis may be to destroy the cell wall and cell membrane by destroying the integrity of the cell structure， thus inhibiting the growth of bacteria even killing bacteria.

Abstract:The changes of whiteness， gel strength， water holding capacity， texture characteristics， storage modulus （G'）， chemical force， protein secondary structure and microstructure of surimi from silver carp were analyzed under different starch concentration， in order to study the effects of native cassava starch， hydroxypropylated starch， acetylated distarch phosphate and acetate starch on the gel properties and protein conformation of surimi. The results showed that starch could significantly improve the water holding capacity of surimi gel. 1% of additive content could improve the whiteness， gel strength， hardness and chewiness of surimi gel， and the improvement effect was the best for hydroxypropylated starch. Rheological properties showed that starch played an inactive filler role in surimi products. A small amount of starch could hinder the formation of hydrogen bond， promote hydrophobic interaction and ion bond formation， and induce conformation transition of surimi protein from a-helix to β-fold structure. A more compact surimi gel network structure could be obtained when four kinds of starch were added to 1%. However， hydroxypropylated starch made the size and distribution of pores in the surimi gel network more uniform. Therefore， 1% hydroxypropylated starch can be used to improve the gel quality of silver carp surimi.

Abstract:Objective： To study and compare the composition， blood sugar lowering effect and composition of BPS， LPS and MPS. Methods： Bailingongfu was selected as representatives of black tea. The composition， molecular weight and monosaccharide composition of plant polysaccharides were determined. The mice diabetes model was induced by streptozotocin， and metformin was used as a positive control to study the hypoglycemic effect of plant polysaccharides， qPCR was used to determine the expression level of related genes in mice liver， and the serum transaminase level in mice was determined. Results： The molecular weights of BPS， LPS and MPS are 8 745， 22 410 u and 34 430 u， respectively. The selected plant polysaccharides have hypoglycemic effect， the fasting blood glucose decline rates of BPS， LPS and MPS were 61.6%， 52.8% and 53.8%， respectively. Plant polysaccharides can increase the activity of enzymes related to glycolysis and down-regulate the expression of Foxo1， G6Pc， PEPCK and TXNIP genes in mice. The hypoglycemic effect showed the regularity of black tea > mulberry leaf > Lycium barbarum fruit. Conclusion： Under the selected dose condition， the plant polysaccharides didn′t show hepatotoxicity. The research on the hypoglycemic effect of the selected black tea polysaccharide is better than the mulberry leaf polysaccharide and the Lycium barbarum fruit polysaccharide.

Abstract:To investigate the effects of chlorophyll on related inflammatory markers in obese mice， so as to explore the biological activity of chlorophyll. Chlorophyll was administered to the obese mice to measure blood sugar， body weight， food intake and other indicators while feeding the high-fat feed. Serum inflammatory factors（TNF-α， IL-6， LEP） and serum endotoxin （ET） were measured by ELISA to analyze the effect of chlorophyll on inflammatory factors in obese mice. The results showed that chlorophyll can significantly reduce inflammatory factors and ET level（P<0.05）， and promote the increase of adiponectin level， which has effects on obesity-related inflammation.

Abstract:Objective： The phenolic substances in the extract of Agrocybe chaxingu Huang and its effect on antioxidant activity in vivo and in vitro were studied. Method： Based on the analysis of total phenols， total sugars and antioxidant activities in vitro of water/ acetone/ ethanol extract of A. chaxingu， the antioxidant activity of A. chaxingu aqueous extract [total phenols， 12 mg/（kg bw·d）] on normal mice （gavaged for 10 days） was detected， which made ferulic acid and vitamin E as positive control group， and physiological saline as blank control group. Then， the antioxidant activity of A.chaxingu aqueous extract [based on total phenols， 10， 20， 40 mg/（kg bw·d）] on the D-galactose induced aging mice was evaluated. Result： The content of total phenols of A. chaxingu aqueous extract was 1.25‰， which between acetone extract and ethanol extract. When the concentration of A. chaxingu aqueous extract was 60.00 mg/mL， the scavenging rate of hydroxyl radicals and the inhibition rate of polyunsaturated fatty acid （PUFA） were 87.00% and 65.31%， respectively， which were more higher than acetone extract and ethanol extract. The results of antioxidant activity on normal mice showed that the A. chaxingu aqueous extract did not affect the weight growth， but increased the liver index and spleen index. The activity of SOD in serum of A. chaxingu aqueous extract increased and reached 130.43 U/mL， while the content of MDA decreased obviously compared with the physiological saline group （P<0.05）. Antioxidant capacity of ， aqueous extract was equivalent with vitamin E and ferulic acid. The results of antioxidant activity on D-galactose induced aging mice showed that 10， 20， 40 mg/（kg bw·d） of A. chaxingu aqueous extract could significantly decreased the content of MDA （P<0.01）， and the decrease rate of MDA of 20 mg/（kg bw·d） group was the highest and reached 94.53%. The GSH-Px activity of 10 mg/（kg bw·d） group increased extremely significantly 22.98% （P<0.01）. Conclusion： The A.chaxingu aqueous extract had antioxidant activity in vivo and in vitro， and phenolic substances were the main functional components. A. chaxingu aqueous extract could maintain the body's antioxidant homeostasis and significantly amelioration the D-galactose induced aging damage by increasing the activity of antioxidant enzymes （SOD， GSH-Px） and reducing the content of MDA.

Abstract:The gelatinization degree， whiteness value， sensory score， cooking characteristics and texture characteristics were used as the quality evaluation indexes of rice cake to investigate the effect of gelation time， temperature and humidity on the quality of rice cake. The optimization process were determined by orthogonal optimization experiment. Under the optimized process， the changes of water distribution and microstructure of rice cake with different gelation time was researched. Result： Gelation time， gelation temperature and gelation humidity changed the quality of rice cake by affecting gelation extent， velocity and water distribution， respectively. The optimal process was gelation time 18 h， gelation temperature 25 ℃， gelation humidity 80%. During the gelation process of the rice cake， the tightly bound water was separated from the end of the cluster structure chain and transformed to the less tightly bound water， and finally dispersed into the environment in the state of free water to deepen the gelation behavior， while specially the less tightly bound water existed as the intermediate between the tightly bound water and the free water. The microstructure indicated that the macromolecular clusters in the texture concentrate preferentially and form small pore structures. When the gelation behavior was almost complete， the structure became compact and continuous wall shape.

Abstract:Objective： To study the viscosity reduction technology for wastewater from the processing of preserved cherry tomato and its effect on the quality of preserved fruit. Methods： The suitable viscosity reducer was selected from six kinds of reagents， and the viscosity reduction conditions were determined with kinematic viscosity and turbidity as indicators. The sugar permeation rate of the reusable sugar cooking liquid was compared and studied， and finally the viscosity reduction technology was established. In order to evaluate the effect of viscosity reduction technology on the quality of preserved cherry tomato， the nutritional components， antioxidant capacity and sensory flavor of preserved fruit were determined. Results： Bentonite （0.12%） was selected as the viscosity reducing agent of the waste liquid and the viscosity reduction technology was established. The water-soluble nutrients， comprehensive antioxidant capacity， total free amino acid content （3.499%）， total volatile flavor substance content （1 463.737 μg/kg）， total characteristic volatile substance content （265.349 μg/kg） and overall sensory evaluation value（77.00） of the preserved cherry tomato treated with bentonite were determined， which was higher than that of fresh sugar water group（P<0.05）， and there was no significant difference in fat soluble nutrients. However， the direct reuse of the waste concentrate would significantly affect the fat soluble nutrients， comprehensive antioxidant capacity and sensory flavor of preserved fruits. Conclusion： The viscosity reduction technology could improve the nutritional composition， antioxidation and sensory flavor of the preserved fruits.

Abstract:In view of the current research status of probiotic fermented dairy products， which are mixed animal strains for fermenting animal source dairy products， this paper uses oats as the main raw material to prepare pure oat milk， enzymatic hydrolysis， adding 20% milk and 7% sucrose and appropriate amount of emulsifier. The stabilizer is composed of a fermentation medium. The Lactobacillus casei 05-20， which is selected from the fermented dairy products and has high growth and fertility and high fermentation activity， is used as a test strain to study the single factors such as inoculum size， fermentation temperature and fermentation time. The effect of Lactobacillus casei pure fermented oat milk product quality， the response surface test was used to optimize the process conditions of Lactobacillus casei pure fermented oat milk product， analyzed and evaluated the quality of Lactobacillus casei pure fermented oat milk product， including： sensory， physical and chemical ingredients， probiotics and functional ingredients， food safety， storage stability. The results showed that the optimum conditions for the fermentation of oat milk by Lactobacillus casei were 5.0% inoculation， 37 ℃ fermentation temperature and 5.3 h fermentation time. The fermented milk was yellowish， fine and fine in texture， with rich aroma of oatmeal and fermented aroma， fermented milk live bacteria number reached 8.8×108 CFU/mL， titration acidity was 49.05 °T， protein content was 1.76 g/100 g， fat content was 0.75 g/100 g， essential amino acid content accounted for 55.92% of total amino acid content， unsaturated fatty acid content was about 79.20% of total fatty acid content， oat β-glucan content was （92.00 ± 1.29） μg/mL， total phenol content was （13.00 ± 0.38） μg/mL， anti-digestion mass fraction was （19.61±0.02）%， no therapeutic microorganisms and toxins were detected， and the shelf life was 24 days. It provides a theoretical basis for the industrial production of Lactobacillus casei fermentation with plant protein oats-based dairy products， it also provides a new way for new probiotics to ferment other vegetable protein dairy products.

Abstract:In order to explore the effects of fermentation time， fermentation temperature and the rice wine addition on the quality of rice wine sourdough and rice wine sourdough steamed bread， by the 3，5-dinitrosalicylic acid spectrophotometry， gluten index analyzer， pH meter， millet volume replacement method， whiteness meter， hardness meter and sensory score， the pH value， reducing sugar content， wet gluten content and gluten index of rice wine sourdough， as well as specific volume， whiteness， hardness and sensory score of rice wine sourdough steamed bread were evaluated. The results showed that with the increase of fermentation time， reducing sugar content and pH value of rice wine sourdough decreased first， then increased and finally decreased. When the fermentation time was more than 8 h， the wet gluten content and gluten index of rice wine sourdough were significantly reduced. When the fermentation temperature was 25 ℃， the pH of rice wine sourdough was significantly higher than other temperatures， while the reducing sugar content was significantly lower than other temperatures. With the increase of fermentation temperature， the wet gluten content and gluten index of rice wine sourdough showed almost the same law， which was a decreasing trend. The gluten index could be reduced when the rice wine addition was more than 6%. The optimum conditions were fermentation time of 10 h， fermentation temperature of 27 ℃ and rice wine addition of 10%. The sensory score was 88.0 ± 0.56， which was in accordance with the predicted value.

Abstract:In order to investigate the change regulation of sulfhydryl groups （SH） and disulphide bonds （SS） in protein in noodle processing and its effect on the noodle quality， the flour samples with different content of SH and SS bonds were made and the noodles were made of these flours. Seven important sample points included knead dough， fragmentary dough maturation， dough sheet maturation， rolling and slitting， cooking， drying at constant temperature and humidity， and drying at room temperature. The gliadin and glutenin macropolymer（GMP） were extracted and the changing law of content of SH and SS bonds in gliadin and GMP were also studied. Results： There were obvious differences on free-SH， SS bond and the ratio of free SH/SS. For the extracted gliadin and GMP， there was no obvious change at other points except for cooking where the free-SH decreased obviously and SS content increased synchronously in gliadin. The change range of free-SH and SS bonds in GMP was relatively spacious. In flour samples with SS bonds content of 13.26， 12.95， 12.80， 12.55， 12.46 μmol/g， respectively， the free-SH content gradually increased， and SS bonds content gradually reduced， and the change amplitude became bigger and bigger. This study revealed the change regulation of SH and SS in protein in noodle processing and laid a theoretic foundation for further investigating the structure changes of gluten protein and noodle quality.

Abstract:In this experiment， soybean was used as raw material， and the effects of buffer solution， aqueous phase and enzymatic methods on the extraction rate， composition， fatty acid composition， phospholipids， tocopherols， ζ-potential and particle size of soybean oil body were compared， and the effects on the oxidation stability of soybean oil body were analyzed. The results showed that the extraction rate of soybean oil body by enzymatic method（19.74 ± 0.14）% was significantly higher than that by buffer solution method （12.76 ± 0.14）% and aqueous method （6.67 ± 0.32）% （P<0.05）. There were significant differences in the composition of soybean oil body， fatty acid composition， phospholipid and tocopherol content， ζ-potential and particle size of soybean oil body extracted by different methods （P<0.05）. On the first day after storage at 60 ℃， the peroxide values of soybean oil body extracted by buffer solution， enzymatic method and aqueous phase method respectively were（1.67 ± 0.14），（1.84 ± 0.10），（1.64 ± 0.00） μg/mL， there was no significant difference（P＞0.05）. The TBARS of oil body extracted by aqueous phase method（1.14 ± 0.01） μg/mL was significantly higher than that by enzymatic method （1.02 ± 0.02） μg/mL and buffer solution method （1.09 ± 0.02） μg/mL （P<0.05）； the TBARS of soybean oil body extracted by buffer solution method was significantly higher than that by enzymatic method （P<0.05）； the acid value of oil body extracted by enzymatic method （0.71 ± 0.02） μg/mL was significantly lower than that by aqueous phase method （0.96 ± 0.13） μg/mL and buffer solution method （0.93 ± 0.09） μg/mL （P<0.05）. There was no significant difference between aqueous phase method and buffer solution method（P＞0.05）. Therefore， the composition and physicochemical properties of soybean oil body obtained by different extraction methods were significantly different（P<0.05）， the soybean oil body extracted by enzymatic method has the highest extraction rate， the highest fat content and the best stability.

Abstract:To develop a new process for producing chitin from crayfish shell， demineralization and deproteinization of crayfish shell by electrolyzed water （EW） were studied， and the physicochemical properties and structure of chitin extracted were characterized. The results showed that after crayfish shell powder （CSP） was treated individually with acidic electrolyzed water （AEW） and basic electrolyzed water （BEW） prepared by 2% NaCl for 6 h， the mineral and protein removal rates were 99.59% and 91.31%， respectively. After CSP was continuously treated by the combination of AEW and BEW for 9 h， the ash and protein contents of chitin prepared were 0.86% and 1.31%， respectively. AEW also had good decolorizing effect. Compared with the traditional inorganic acid-base method， the chitin produced by the EW treatment process had lower intrinsic viscosity （368 mL/g）， molecular weight （85 ku） and degree of deacetylation （12.88%）. The results of thermogravimetric analysis and differential thermal analysis， scanning electron microscopy， Fourier transform infrared spectroscopy and X-ray diffraction showed that both chitins exhibited a network-like porous structure and all were α-chitin. The degradation temperature of them were 382 ℃ and 389 ℃， respectively， and the crystallinity index were 82.48% and 78.82%， respectively. Therefore， EW treatment process has the potential to be a novel method for producing chitin from crayfish shell.

Abstract:In order to realize the high-value utilization of octopus waste， the octopus ink sac was used as the raw material. The study compared high-speed centrifugal method and enzyme method to extract octopus ink melanin， and explore its ultrastructure， ultraviolet-visible spectrum， physical and chemical properties. The results showed that the melanin extracted by high-speed centrifugation has two characteristic absorption peaks at the wavelength of 230 nm and 326 nm in the ultraviolet region. The average particle size is 123 nm， and the structure is intact. Analysis of physicochemical properties of octopus melanin indicates it was insoluble in most organic and inorganic reagents， would precipitate in acidic solution， was slightly soluble in alkaline buffer， and had good solubility in NaOH solution； under natural light conditions， the octopus melanin had good stability， but it was intolerant in the ultraviolet light. Under long time high temperature heating condition， the melanin was instable. Under different pH value conditions， the stability of octopus melanin increased with the increase of solution alkalinity. This study provides data support for the comprehensive utilization of melanin in octopus ink sacs.

Abstract:The film based on whey protein（WPC）， the effects of different film-forming methods on the properties and application characteristics of the film were studied. The results showed that the best process condition of film formation by physical method was pH 8.0， ultrasonic power 240 W， 90 ℃ heat treatment； the chemical method was to add 4.0% glycerine as plasticizer， 0.10% L-cysteine as reducer and 0.20% ferulic acid as cross-linking agent； enzymatic method was that the amount of transglutaminase（TG） was 20 u/g protein， enzymatic hydrolysis at 50 ℃ for 90 min. At the optimum reaction condition， the mechanical properties and barrier properties of whey protein films have been improved to a certain extent. By measuring the weight loss rate， ascorbic acid content and sensory evaluation of virgin fruit， the preservation effect of whey protein film on cherry tomatoes was： enzymatic method > chemical method > physical method， and the three methods were better than the control group without coating.

Abstract:Some bamboo products are often used for food packaging or food contact materials. In order to study the antiseptic effect of chitosan on bamboo. The experiment of chitosan（food additive） inhibiting the growth of fungi， which caused bamboo products to go moldy was carried out. Fungi was separated and purified from moldy bamboo product. Different concentrations of chitosan treated bamboo product at ambient temperature， or 100 ℃， or with ultrasound assisted soak. After treatment they were inoculated with fungi， and the total number of colonies was determined. Viscosity changes and fungal inhibition of chitosan treated by different high temperatures were determined. Chitosan soaking treatment can increase the anti-corrosion of bamboo. Combining with heating soak， the antifungal effect will be greatly improved. Ability of bamboo materials absorbing chitosan will fine when it was soaked at less than 60 ℃. The optimum treatment was bamboo product soaked with 5 mg/mL chitosanat 60 ℃ for 24 h.

Abstract:The objective of this study is to investigate the effect of active modified atmospheres （Active MAP） on the inhibition of mold. In this study， Cladosporium link was used as test material， and the initial gas proportion of O2/CO2 including 60%O2+40%CO2， 70%O2+30%CO2， 80%O2+20%CO2， 90%O2+10%CO2， and natural air （ck） were employed. During storage at （28±0.5） ℃， the colony diameter， spore amount， cell membrane permeability， release of cellular contents， and subsequent effects of growth curve， polygalacturonase （PG）， polymethylgalacturonases （PMG）， superoxide dismutase （SOD）， and catalase （CAT） were periodically measured. The results showed that O2/CO2 active MAP significantly inhibited the colony expansion rate and sporulation rate of Cladosporium link， reduced the activity of SOD， CAT， PG， and PMG， destroyed the cell membrane integrity， increased the cell membrane permeability and release of cellular contents. Furthermore， the antibacterial effect was significantly enhanced along with the increase of CO2 ratio. This study provides a theoretical basis for mold control during fruits and vegetables storage.

Abstract:Objective： To explore the effect of cholesterol treatment on the preservation of postharvest pak choy （Brassica chinensis L）. Method： Postharvest detached pak choy was completely immersed in 0.1 mmol/L cholesterol solution for 2 h and stored at 2 ℃. Quality related parameters of pak choy were determined during the storage. Result： Exogenous cholesterol treatment could significantly retard the decline of ascorbic acid （AsA）， and the increase of weight loss rate， nitrites and malondialdehyde（MDA）. Cholesterol also contributed to the preservation of soluble protein， chlorophyll and soluble solids content（SSC）. Cholesterol treatment could effectively enhance the activities of superoxide dismutase（SOD） and ascorbic acid peroxidase （APX）， as well as catalase （CAT） and glutathione reductase （GR）. However， little effect was found on peroxidase （POD）. Cholesterol could stably promote the activities of APX and GR enzymes， and APX， AsA and GR were positively correlated with chlorophyll. Conclusion： Cholesterol treatment was beneficial to maintain the quality of postharvest pak choy， sustain the content of reduced AsA， and keep pak choy green.

Abstract:In this paper， the strain of Bacillus coagulans VP4 with strong antimicrobial activity was screened from Shanxi aged vinegar cupei. After eliminating some interference factors such as organic acids， hydrogen peroxide and hydrolization with proteinase K and trypsin， the antibacterial substance in the culture supernatant was confirmed as proteinaceous and was a kind of bacteriocin. The bacteriocin showed pH value stability in the range of 2-10. Moreover， after being treated at 121 ℃ for 60 min， the antimicrobial activity of VP4 bacteriocin still remained at 70%. Also， the biopreservative effect of VP4 bacteriocin on quality of fresh mutton stored for 15 days at 4 ℃ were investigated based on the microbial， chemical （pH， electric conductivity， total volatile basic nitrogen， thiobarbituric acid）， and sensory evaluation. The results showed that VP4 bacteriocin could retain the good quality and extend the shelf life of mutton during storage at 4 ℃. Bacillus coagulans VP4 bacteriocin has thus shown a great potential as a natural biopreservative substance in chilled meat.

Abstract:The quality and physicochemical properties of pretreated sea cucumber in 60 days at 4 ℃ were studied. The soluble collagen content， hardness and chewiness， protein degradation， cathepsin-L and caspase-3 activity， structural protein expression and free radical production of sea cucumber were analyzed regularly. The results showed that with the prolongation of low temperature treatment time， the indexes of the early stage were not significantly changed， and the soluble collagen content increased significantly from the 10th day； the hardness and chewiness decreased sharply at 15-25 d. The results of SDS-PAGE showed that the high molecular weight protein began to decrease on the 15th day， and the actin disappeared after 30 days. The activity of cathepsin-L increased significantly at 20 days， and the activity of caspase-3 reached the maximum at 25 days. After 30 days， the β-actin protein signal was significantly attenuated. The results of ESR showed that the ROS signal intensity increased first and then decreased with time. This study provided a theoretical basis for the storage and preservation of sea cucumber.

Abstract:To investigate whether the acid-resistant candidate genes ATPase and FtsH with different expression trends under stress conditions can improve the acid resistance of strains， the real-time quantitative PCR （RT-qPCR） was used to determine the relative expression levels of mutagenized Oenococcus oeni， acid-resistant strain b1 and acid-sensitive strain b2， in ATB medium at pH 4.8 （optimal condition） and pH 3.0 （stress condition）. Then their expression trends were analyzed. ATPase and FtsH were cloned from b1， which were named ATPase1 and FtsH1； ATPase and FtsH were cloned from b2， which were named ATPase2 and FtsH2. Next analyzed the sequence differences. The function of ATPase1， ATPase2， FtsH1 and FtsH2 were verified in Lactobacillus plantarum （L. plantarum） XJ25， to establish recombinant L. plantarum a1， a2， f1 and f2. The growth ability of recombinant L. plantarum was determined in MRS medium at pH 3.2， using L. plantarum con containing empty vector as a control. Quantitative results showed that ATPase was significantly up-regulated in both strains b1 and b2； FtsH was unchanged in b1 and significantly up-regulated in b2. ATPase1 and ATPase2 have three non-synonymous mutations in the functional domain， and FtsH1 and FtsH2 have one non-synonymous mutation in the transmembrane domain. The functional verification results showed that the growth ability of a1 and a2 was stronger than con， and there was no difference in the growth ability between a1 and a2； the growth ability of f1 was stronger than that of con， and the growth ability of f2 was not different from that of con. It can be seen that ATPase1， ATPase2 and FtsH1 can all improve the acid resistance of the strain.

Abstract:As a new resource food， Moringa oleifera leaves has attracted much attention for its hypoglycemic activity， however， the active components need further study. The chemical fingerprint can distinguish the difference of chemical content in medicinal materials， and the spectrum-effect correlation analysis can preliminarily predict the active component groups. The insulin resistance model of HepG2 was used to evaluate the hypoglycemic activity of Moringa oleifera leaves， and the main active components with hypoglycemic activity in Moringa oleifera leaves were identified by the spectrum-effect correlation analysis with fingerprint. This paper evaluated the hypoglycemic activity of different extracts from orthogonal test and found that Moringa oleifera leaves could increase the glucose consumption of insulin resistant HepG2 cells and effectively alleviate insulin resistance. Spectrum-effect correlation analysis indicated that apigenin-7-O-glucoside， quercetin-3-O-glucoside， kaempferol diacetyl-rhamnoside， kaempferol had higher correlation coefficient and they were 0.991 （P < 0.01）， 0.915 （P < 0.01）， 0.988 （P < 0.01）， 0.987 （P < 0.01）， respectively. The results of this study provided the basis for the discovery of hypoglycemic active component group of Moringa Oleifera leaves. The hypoglycemic active component group of Moringa Oleifera leaves might be apigenin-7-O-glucoside， quercetin-3-O-glucoside， kaempferol diacetyl-rhamnoside， kaempferol.

Abstract:The fermented milk is considered as a complex food system， measurement of all metabolites in fermented milk using a single analytical platform is usually unattainable. Fermented characteristics was investigated， and metabolites profile of Lactobacillus plantarum P-8 in strain-dependent fermentation and co‐fermentation with commercial starters YC-X11 was analyzed by ultra-performance liquid chromatography- quadrupole-time of flight mass spectrometry （UPLC-Q-TOF） combined statistical methods. When the single strain of Lactobacillus plantarum P-8 was used in the fermentation， the time to reach the end point was 13 hours. The fermentation time required 5 hours with both Lactobacillus plantarum P-8 and commercial starter YC-X11. During the fermentation process， the bacterial viable counts in different fermented milk significantly increased （P ＜ 0.05）， and the titratable acidity significantly increased （P ＜ 0.05）. 62 metabolites were determined as the major compounds contributing to the discrimination of fermented milk. The different metabolites between the mixed fermented milk and the fermented milk with Lactobacillus plantarum P-8 were organic acid （7 species）， polypeptide （4 species）， free amino acid （4 species）， nucleic acid metabolites （4 species） and aromatic substance （3 species）. Therefore， metabolomic methods can be used to identify and analyze different metabolites in fermented milk， which could serve as potential biomarkers.

Abstract:Objective： The effect of different fermentation characteristics of Lactococcus lactis on the quality of fermented milk was explored. Methods： Fermented milk were made with 191 Lactococcus lactis strains that the flavor and taste of fermented milk were assessed by electronic nose， electronic tongue， and multivariate statistical analysis. Results： Principal component analysis（PCA） showed separation trends in the flavor and taste of the fermented milk samples by the strains that had different acid-producing rates and proteolytic activity. Mann-Whitney test showed that aromatic compounds of the fermented milk made by moderate and fast acid-producing strains more than fermented milk made by slow acid-producing strains， while opposite trends were observed in methane， ethanol and organic sulfur （P<0.01）. In terms of taste， there was strong umami of the fermented milk made by slow acid-producing strains and the more sourness of fermented milk made by moderate and fast acid-producing strains（P<0.01）. There was a significantly negative correlation between acid-producing capacity and proteolysis level（P<0.01）. Conclusion： The fermented milk produced by the fast acid-producing and low proteolysis level Lactococcus lactis had more aromatic compounds， and were sourer， while fermented milk produced by the slow acid-producing and strong proteolysis level strains had more methane， ethanol and organic sulfur， and stronger umami taste.

Abstract:The ultra performance liquid chromatography-tandem mass spectrometry method was established to quantify the bovine serum albumin in bovine dairy products accurately based on targeted proteomics. Qualitative analysis of theoretical peptides was carried out using high-resolution mass spectrometry （Q-Orbitrap） and protein software. Based on the the specificity and stability of peptides and the dynamics curve of enzymatic hydrolysis， LVNELTEFAK and HLVDEPQNLIK were selected as the specific proteotypic peptides for quantitative determination of bovine serum albumin. The detection limits of both peptides were less than 1 mg/100 g. And the recovery rates were between 87.9% and 101.1%， the intra-day and the inter-day precisions were less than 7.6%. The detection of 12 infant formula and whey powder showed that the method was suitable for the quantitative detection of bovine serum albumin in dairy products. It provides a technical foundation for quality monitoring of infant formula.

Abstract:Objective： To isolate， identify and analysis the strains with high cholesterol-lowering activities from traditional ferments. Methods： Strains were screened by MRS， M17 and PDA culture media， and explore the tolerance of bile salt， acid resistance， hydrophobicity， self-cohesion ability， bile salt hydrolytic enzyme activity and cholesterol lowering properties. Results： 51 strains were isolated from ferment， among which S-8， M-7 and M-16 had better cholesterol-lowering capacity and the cholesterol reduction rates were 25.43%， 37.06% and 47.41%， respectively. The tolerance of bile salt tolerance were 42.09%， 65.64%， 22.80%； S-8 strain had the highest hydrophobicity in xylene， and the hydrophobicity was up to 35.91%， and the hydrophobicity of M-7 in chloroform was 45.22%. Both strains have good acid resistance and self-cohesion， after standing for 24 hours， the self-cohesion ability was more than 80%. The cholesterol-lowering effect was investigated. It was found that the intracellular enzymes were mainly responsible for this activity and had 7 times higher specific activity than the extracellular ones. Conclusion： Through the morphological observation and 16S rDNA molecular analysis， the S-8 strain was identified as L. paracasei strain， the other two strain were identified as Staphylococcus hominis strain. It is possible to further study microorganism on the regulation of lipid metabolism.

Abstract:Through smell the strain which produce intense ester-flavor was screened. The ability of producing ester was different in different substrate. This flavor produced by strain in the millet media was strongest. The main aroma materials in the millet media were ethyl acetate. The relative contents of ethyl acetate on the total flavor components was 37.71%. The strain FJZ was identified by the method of morphology， physiological and biochemical test， and molecular biology， the result showed that the strain FJZ was Pichia kudriavzevi. It was named P. kudriavzevi FJZ. The strain FJZ could grow in the condition of pH 1.5-10.5， temperature 28-42 ℃， alcohol volume fraction 0%-14%， sugar mass fraction 10%-60%. The optimal growth conditions of the strain FJZ was sugar mass fraction 20% and alcohol volume fraction 6%.

Abstract:Purpose： In order to investigate the composition of microorganisms in apple natural fermentation Jiaosu and explore the dominant flora in different stages of fermentation. Method： The metagenomic analysis was used to analysis the composition and changes of fungi and bacteria in the three periods of pre-fermentation （10 d）， medium （20 d） and post- （35 d） of apple natural fermentation Jiaosu. The results showed that diversity analysis showed that the diversity of bacteria was higher than that of fungi. The diversity of bacteria was the highest in the early period and decreased first and then increased， slight increase in fungal diversity. In the genus level analysis， bacteria were mainly Lactobacillus， Gluconobater， Lactococcus， Weissella， Leuconosloc and Acetobacter. Among them， Lactobacillus （58.73%， 49.08%， 56.34%） and Gluconobacter（20.42%， 34.72%， 24.64%） were the dominant genus in bacteria， fungi were mainly Saccharomyces， Hanseniaspora and Zygosaccharomyce. Among them， Zygosaccharomyce （89.5%，18.2%，80.3%） and Hanseniaspor （9.7%，60.6%，8.7%） were dominant genus. Conclusion： The dynamic changes and diversity mechanism of apple ferment in the process of natural fermentation were clarified， which provided practical guidance and theoretical basis for the subsequent development of a new type of artificial controllable apple Jiaosu.

Abstract:Established the qualitative and quantitative method for the determination specific migration of benzene compounds （migration of 13 kinds of benzene compounds in ethanol aqueous solution） in water and 4% acetic acid aqueous solution in AS/ABS by headspace-gas chromatography tandem mass spectrometry containing benzene， toluene， ethylbenzene， p-xylene， m-xylene， o-xylene， 1，3，5-trimethylbenzene， styrene， cumene， n-propylbenzene， sec-butylbenzene， butylbenzene， 1，2，4-trimethylbenzene and 1，2，3-trimethylbenzene. By optimizing the separation ratio， carrier gas flow rate， programmed heating rate， equilibrium temperature and time， the chromatographic conditions， the DB-WAXMS column （30 m × 0.25 μm × 0.25 mm） was used to separate benzene， xylene， tritoluene and propyl benzene， effectively. The linear correlation coefficient was more than 0.9950， the detection limit with 10S/N was 0.6-2.1 μg/kg， the recovery rate was 80.2%-118.3%， the relative standard deviation 3.6%-9.7%， the rapid qualitative and quantitative analysis of 14 benzene compounds in AS/ABS was realized. Investigated the migration law of benzene compounds in AS/ABS of food contact products at temperatures of different temperature and different time， the higher the temperature， the greater the specific migration of benzene compounds. At the same time， the migration model of benzene compounds at different temperatures is established and the kinetic parameters such as diffusion coefficient DP， characteristic parameter Ap， activation energy Ea are determined. Finally， the establishment of a mathematical model for risk assessment of benzene compounds in AS/ABS of food contact materials provides a basis for risk control of benzene compounds.

Abstract:Objective： To establish a sensitive and rapid one-step reverse transcriptase droplet digital polymerase chain reaction （RT-ddPCR） assay for detection human astrovirus （HAstV） in different food matrices. Methods： The RT-ddPCR quantitative detection assay for HAstV was established and optimized by applying the selected specific primers and probes. The specificity of this quantitative method was validated via using other foodborne viruses RNA as targets. A HAstV RNA reference material was series diluted to evaluate the quantitative detection limit， accuracy and variability of the developed assay. In order to test the detection limit and recovery rate in food， artificial positive samples were prepared by adding MS2 bacteriophage with known titer to different food matrices. Virus elution and purification method in food from CEN ISO/TS 15216-2：2013 was adopted and the virus detection amounts of two RNA extraction methods were compared. Results： The HAstV RT-ddPCR assay had better accuracy， sensitivity and smaller variability with a detection range from 105 to 100（copies/μL） and a lower limit of quantitation of 5 copies/μL. The detection limits in digestive glands of bivalve molluscan shellfish， food with hard surface， raw vegetables and soft fruits were 7.2×106-3 600 copies， 7.2×106-3 600 copies， 7.2×106-7 200 copies and 7.2×107-7 200 copies， respectively. In higher contamination level， detection amount of virus was significantly lower （P＜0.05） when RNA was extracted and purified by trizol combined with magnetic beads. A statistically significant difference （P＜0.05） in virus recovery rate among different food matrices was indicated by one-way ANOVA and Turkey multiple comparison analysis. Conclusion： The established RT-ddPCR assay in food could effectively detect HAstV in contaminated food. However， the single RT-ddPCR quantitative result could not reflect actual virus load in food which could be calculated by applying recovery rate.

Abstract:A rapid method was presented for the determination of 19 quinolone antibiotics in milk by ultra high performance liquid chromatography/ quadrupole orbitrap high resolution mass spectrometry. Milk samples were extracted by acidified acetonitrile and purified by PRiME HLB solid phase extraction column， then separated by Waters Acquity BEH C18 column （100 mm×2.1 mm， 2.5 μm） using a binary solvent system composed of acetonitrile and water（0.1% formic acid） by gradient elution. The analytes were determined by quadrupole-orbitrap high resolution mass spectrometry in full-MS and data-dependent scan （ddMS2） mode. The results showed that mass accuracy error of the 19 quinolones were lower than 3.0×10-6， linear relationships were well in the range of 0.2-200 ng/mL for 19 antibiotics， and correlation coefficients were higher than 0.998. The LODs were in the range of 0.1-0.5 μg/kg and the LOQs were in the range of 0.2-1.0 μg/kg. With spike levels in the range of 0.2-10.0 μg/kg， recovery of the method was in range of 62.1%-100.4% and relative standard deviations were lower than 10%. The method is simple， rapid， accurate， which is suitable for the rapid screening and quantitative analysis of 19 kinds of quinolones antibiotics in milk sample.

Abstract:Antibacterial activity of ethanol extract from Allium prattii against Staphylococcus aureus was analyzed by broth dilution and Oxford cup methods. Effects of ethanol extract from A. prattii on contents of extracellular metal ions and biological macromolecules（i.e. proteins， nucleic acids and polysaccharides）， conductivity of culture medium， integrity of cell walls and ultrastructure of S. aureus were investigated using atomic absorption spectrometry， scanning electron microscopy and so on. Phytochemicals of ethanol extract from A. prattii were quantified by high-performance liquid chromatography. And antibacterial mechanism of ethanol extract from A. prattii was discussed. The minimum inhibitory mass concentration of ethanol extract from A. prattii was 15 mg/mL. After S. aureus was treated with ethanol extract from A. prattii， contents of extracellular K+， Ca2+， Na+， Mg2+， proteins， nucleic acids and polysaccharides markedly increased， and conductivity of culture medium significantly improved. Ethanol extract from A. prattii seriously destroyed cell morphology. Two sulfur compounds （allicin and alliin）， four nitrogen compounds （uridine， β-thymidine， adenosine and 2'-deoxyadenosine monohydrate） and four flavonoids （rutin， kaempferol， quercetin and isorhamnetin） were detected in ethanol extract from A. prattii. Antibacterial activity of ethanol extract from A. prattii against S. aureus was possibly attributed to its phytochemicals such as rutin， quercetin， allicin and kaempferol.

Abstract:In order to explore the effects of different edible oils and fried foods on the formation of trans fatty acids， five varieties of edible oils （sunflower oil， soybean oil， rapeseed oil， palm oil and peanut oil） were used to fry 14 batches of fritters at a certain temperature. The fritters， in turn， use soy-fried tofu， fritters and chicken legs to analyze the frying oil produced in both cases by gas chromatography to compare the trans fatty acid content. The results showed that the content of trans fatty acids in edible oil increased with the extension of frying time. The total content of trans linoleic acid in sunflower oil was the highest， reaching about 12 mg/g， and the trans oleic acid was lowest in peanut oil， about 0.6 mg/g. The content of trans fatty acids in soybean oil did not change significantly during the frying process， and remained at about 3.5 mg/g. It can be seen that the trans fatty acids produced by different types of edible oils have a large difference in heating process. When using soybean oil to fry tofu， fritters and chicken legs respectively， there is no significant difference in frying oil trans fatty acids. Indicating the frying process， the trans fatty acids are mainly derived from the oxidative cleavage and isomerization of unsaturated fatty acids in edible oils， and have little to do with frying materials. From the perspective of the formation of trans fatty acids， it is recommended to use soybean oil for long-term frying in cooking， and it is not suitable to use sunflower oil.

Abstract:The n-3PUFA in the seal oil ethyl ester was enriched by urea adduction and molecular distillation. The physicochemical index， fatty acid composition and volatile substance in the seal oil during the enrichment were analyzed by physicochemical analysis， GC and HS-SPME-GC-MS. The results showed that the saponification value and iodine value were significantly improved by urea adduction and molecular distillation while had no significant effect on the acid value and peroxide value. The content of SFA was significantly decreased after urea adduction while n-3PUFA present the opposite tendency. There was a significant decrease in the content of MUFA. However， some long chain MUFA （C16：1，C18：1 and C20：1） still occupied larger percentage. The SFA and MUFA were separated effectively after molecular distillation and products with n-3PUFA content of 92.96% were obtained. There was no significant difference in the quantity of volatile substances between the material， urea adduction sample and molecular sample. The content of volatile substances in the urea adduction sample was significantly higher than the material and the material was significantly higher than that of the molecular distillation sample. The main volatile substances that contribute to the change were ethanol， 2-ethyl hexanol， fifteen carbon enol， nonanal， undecanal， 3，5-octadien-2-one， 2-nonanone， 2-heptanone.

Abstract:The metabolism disorders of cholesterol would trigger several diseases， which could threaten human health seriously. How to regulate and control the metabolism of cholesterol in vitro and vivo is supposed to be one of the most important issue nowadays. The Lactobacillus is the normal flora existing in human intestine， acting as an important role on adjusting the metabolism. The Lactobacillus can influence the level of cholesterol through regulating the expression of key factors in the process of cholesterol metabolism. Those factors include， the HMG-CoA in the synthesizing process of cholesterol metabolism， the CYP7A1 in the catabolism process of cholesterol metabolism， the ABCG5/G8 and NPC1L1 in the absorption and transportation process of cholesterol metabolism， etc. This paper states the related research in terms of key factors that act on the process of the Lactobacillus regulate and control the metabolism of cholesterol. The aim of the paper is to provide theoretical basis of further study on Lactobacillus regulate cholesterol metabolism.

Abstract:Esters is an important active aroma compound in Baijiu， and it has important impacts on the style and quality of Baijiu. Therefore， it is of great significance to study its formation mechanism in Baijiu brewing process. Systematic study and analysis of Baijiu brewing process showed that esters in Baijiu mainly came from enzyme-catalyzed reaction of acids and alcohols. Meanwhile， lipase， one of esterification enzyme， plays an important role in the reaction. Therefore， this study analyzes the formation of esters in Baijiu brewing process， and briefly introduces lipase and its catalytic mechanism of ester synthesis. The research progress and prospect of lipase for synthesizing of esters in Baijiu was discussed.

Abstract:Coenzyme Q10 is a natural bioactive compound， which has strong antioxidant properties. It also can improve immunity and prevent cardiovascular diseases. However， poor water-soluble and unstable physicochemical properties， as well as low bioavailability of coenzyme Q10 greatly limit its application in functional food. The delivery carriers of coenzyme Q10 based on natural materials using nanotechnology could solve the aforementioned problems effectively. The domestic and overseas research reports of coenzyme Q10 vehicles in recent years were comprehensive reviewed， and the prospects for their applications in functional food were focused in the paper.

Abstract:With the increasing need for low-fat food along with a simultaneous high demand for fat sensory enjoyment， how to minimize the content of fat meanwhile maximize the sensory evaluation has become an important issue in the food industry. Therefore， the study on sensory mechanism of food fat is becoming increasingly important. This review summarized some sensory mechanisms of food fat and its sensory-related evaluation methodologies， aiming to provide some insights to the academia and food industries.

Abstract:Food texture is a sensory embodiment of the material and structural properties of food， directly affecting the oral behavior， flavor release， and sensory pleasure of food. Food texture is also an important factor affecting consumers' preference and acceptability of food. This paper described the definition and the classification of food texture， perception mechanisms and instrumental measurement of textural properties. It is hoped that the paper will enable better understanding of food texture and its properties， as well as to promote research in this field. It is also hoped that the paper will provide a theoretical basis for the food industry in the design of high quality food.