Abstract:In this paper， we provided an overview of applied and approved projects in 2019 for food science discipline of National Natural Science Fund. We then introduced category-specific application and review based on the four scientific natures of research for food science discipline in 2020 with General Program and Key Program as a trial.

Abstract:To investigate the effect and mechanism of Matzhu （green ultrafine-powder made from bamboo leaves） as a dietary supplement to protect mice from metabolic syndrome （MS） in mice. Sixty male C57 mice were randomly divided into 6 groups. The MS animal model was built by feeding high fat diet（HFD）， meanwhile utilizing the Matzhu and Matcha as a dietary intervention. After 12 weeks， the body fat， blood lipid and blood glucose level were measured， and inflammatory factors， cytokines and oxidative stress were evaluated， and the gut microbiota was analyzed. The results suggested that the diet added 2.5% Pleioblastus-Matzhu had the best effect on body weight control in mice， the average body weight in this group decreased by 10.9% （P<0.001） compared with HFD group， followed by 2.5% Matcha group （decreased by 7.5%， P<0.001）. This dose of Pleioblastus-Matzhu could significantly ameliorate the blood lipid and blood glucose abnormalities induced by HFD， and prevent fatty liver formation； the level of inflammatory factors decreased significantly （IL-6 was 42% lower than that in the HFD group）； Leptin and lipopolysaccharide levels were significantly decreased （P<0.01）， adiponectin level was significantly increased （P<0.01）， and the intestinal flora maintained good diversity. Research suggested that Matzhu effectively protected experimental animals against the MS via reducing oxidative stress， inhibiting the secretion of inflammatory factors and improving gut microbiota structure， etc. In the two kinds of Matzhu from different bamboo resources， Pleioblastus-Matzhu possessed better effect than Bashania fangiana-Matzhu. Additionally， the additive dose of 2.5% was better than 5.0%. Matzhu is expected to play an active role in the prevention and treatment of chronic diseases with increasing prevalence in human society.

Abstract:Objective： In order to evaluate the mechanism of allergen hypersensitivity. Methods： A mouse model of BALB/C sensitized by αs1-casein was established by oral gavage， and the levels of specific IgE antibodies were used to identify this animal model. The contents of mast cell proteinase， histamine and cytokines in mice were determined， and the clinical and pathological sections were observed. Results： The levels of specific IgE in each group mice increased significantly after the last large dose of αs1-casein was administered to mice at 42th day， and had different degrees of allergic symptoms. Moreover， the allergic reaction in medium and high dose group was stronger than that in low dose group. The levels of mast cell proteinase， histamine， IL-4， IL-5， IL-10 and IFN- gamma cytokines in sensitized mice were significantly higher than those in negative group， and increasing with the accumulation of sensitizing doses. The histopathological section showed that in the medium and high dose groups immunized with αs1-casein， the mice showed obvious inflammatory response， the local alveolar septum collapsed or thickened， and lymphatic foci were produced in the spleen and thymus， and the inflammatory cells infiltrated in small intestinal mucosa mesenchyme. Conclusions： Based on the BALB/C mouse model， the allergic mechanism of alpha αs1-casein was further revealed.

Abstract:Soybean glycinin and β-conglycinin represent up to one third of protein in the soybean. Previous studies indicated that glycinin and β-conglycinin have been characterized as major soybean allergens involved in food allergy. To elucidate the mechanism of mucosal immune-mediated gut allergic reaction induced by soybean glycinin and β-conglyinin， and offered reasons for outcome or preventing of food allergic reactions in susceptible individuals. Balb/c mice were sensitized by gavages with 1 mg/d of glycinin or β-conglycinin for 5 weeks， and T lymphocytes and α4β7 integrin in the intestinal lamina propria and epithelium were counted by immunohistochemistry. Apoptotic lymphocytes in the small intestinal mucosa were analyzed using the terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling（TUNEL） assay， Intestinal secretory-IgA was measured by ELISA. The results showed that increased counts of CD3+， CD4+， CD8+ T cells and α4β7 integrin as well as sIgA level were observed in mice dosed with 1 mg/d soybean protein.

Abstract:In this study， the antioxidant ingredients of Lactobacillus brevis AR247 were explored， then anti-aging effects of L. brevis AR247 on D-galactose induced aging mice were measured. The aqueous phase and intracellular constituents of L. brevis AR247 showed higher antioxidant activity than others. The aging mice model was established by injecting of D-galactose on the concentration of 150 mg/（kg·d） for 6 weeks. These mice were simultaneously administrated by gavage with L. brevis AR247 on the concentration of 1.0×109 CFU/mL （1 mL/100 g）. After for 6 weeks， the activities of catalase （CAT）， superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）， and the contents of glutathione （GSH） and malondialdehyde （MDA） in serum， liver and brain were measured by commercial reagent kits. The contents of Interleukin 2 （IL-2） and tumour necrosis factor-α （TNF-α） in serum were also determined. The results showed that L. brevis AR247 had antagonism effects on D-galactose-induced aging mice such as recovered body weight and brain index to normal levels， and it could increase the activities of CAT， SOD and GSH-Px （P<0.05）， the content of GSH （P<0.05）， and reduce MDA levels （P<0.05） such as reduce the content of MDA in liver to 66.16% of normal group. Compared with the aging model group， the content of serum IL-2 in L. brevis AR247 group was significantly increased （P<0.05）， and it increased to 104.50% of normal group. In conclusion， L. brevis AR247 showed antioxidant and anti-aging effects. The underlying mechanism might be related to improvement of antioxidant function and immune function in the body.

Abstract:The oyster-derived peptide （EVPPEEH） with higher zinc ion binding capacity was prepared by a proteinoid reaction （Plastein） modification with a zinc binding capacity of 161 mg/g. Zinc-deficient SD rats were used as experimental models， and oyster zinc-binding peptide OPZ and zinc-binding peptide modified by plastein reaction LPZ and ZnSO4（ZS） were used as control to study the vivo bioavailability and bioavailability of the oyster-derived metal chelating （EVPPEEH） and zinc conjugate （MZ）. The results showed that the levels of serum zinc， the reserves of femoral zinc and the contents of zinc in the liver and the kidneys in MZ group were significantly higher than those in the control group. Spleen zinc levels MZ group and LPZ group similar recovery， were significantly higher than OPZ group and ZS group. The body weight and food intake of MZ group and each control group were significantly increased， the effect is similar. The expression of ZnT1 in small intestine was not significantly different between MZ group and inorganic Zn group， while the expression of PepT1 was the highest in MZ group， which was 20% higher than that in ZS group， which was significantly higher than that in ZS group each control group. This shows that the absorption and utilization of MZ by the small intestine of rats are partly through the traditional zinc ion pathway and partly through the small peptide pathway. MZ is expected to become a new and efficient zinc supplement.

Abstract:Objective： It was evaluated that the effect and genes related to hepatic cholesterol metabolism of Lactobacillus plantarum KLDS strain on the cholesterol metabolism in hyperlipidemia mice. Method： Health C57BL/6 male mice， as objects， were divided into control group， model group， low-dose group， high-dose group and pravastatin group， which were respectively given normal saline， Lactobacillus plantarum KLDS1.0386 bacteria suspension and pravastatin solution by gavage for 4 consecutive weeks. The serum levels of total cholesterol （TC）， triglyceride （TG）， low density lipoprotein-cholesterol （LDL-C） and high density lipoprotein-cholesterol （HDL-C） were determined on the 28th day of the experiment. The genes related to hepatic cholesterol metabolism （HMGCR， LDLR， SREBP2， CYP7A1， FXR） were investigated in mice. Results： After 4 weeks administration， compared with mice fed a high-cholesterol diet without lactic acid bacteria supplementation， there was a significant（P<0.05） decrease in TG， the total cholesterol and LDL-C levels in the serum， and the mice fed the KLDS1.0386 diet had significantly （P<0.05） the down-regulation of HMGCR and FXR （P<0.05） and the up-regulation of CYP7A1 （P<0.05）. Concluton： Lactobacillus plantarum KLDS1.0386 has probiotic potential as indicated by its hypocholesterolemic effect both in vivo， it could be as the probiotics with cholesterol-lowering activity.

Abstract:Artemisia selengnesis Turcz （AST） is a special food resource of Jiangxi province， and the tender stems of it are often processed into delicious food， but their leaves and root are discarded as directly. This study compared the content of phenolics and flavonoids， antioxidant activity， acetylcholinesterase inhibition， α-glucosidase and xanthine oxidase inhibition of wild and cultivated AST leaves， stems and wild AST root， to aim to provide information for high value utilization of by-products of AST. The results showed that wild and cultivated AST leaves had the higest phenolics （30.12 mg GAE/g DM） and flavonoids （0.63 mg QuE/g DM）， respectively. What’s more， wild AST leaf extract gave the strongest DPPH· scavenging ability， ABTS+· scavenging ability and acetylcholinesterase inhibition， the IC50 value was 0.37， 0.39 and 4.01 mg DM/mL， respectively. The strongest α-glucosidase and xanthine oxidase inhibition was observed in wild AST root extract with the IC50 values of 14.08 and 4.01 mg DM/mL， and the second is wild AST leaf. Correlation analysis indicated that phenolics was the major antioxidant components of AST. Thus， compered to cultivated AST and wild AST stems， wild AST leaves are more suitable as natural resourse of antioxidants， α-glucosidase， acetylcholinesterase and xanthine oxidase inhibitors， and there should have a further study on antidiabetic， anti-hyperuricemia， anti-Alzheimer’s disease effect of it.

Abstract:Acidic and enzymatic methods were used to extract acid-soluble collagen （ASC） and enzyme-soluble collagen （PSC） from flounder bones. The UV， IR spectra， subunit composition （SDS-PAGE）， thermal stability （DSC）， microstructure（SEM） and rheological properties（DHR） of ASC and PSC were studied. UV spectra showed that ASC and PSC had the maximum UV absorption peaks at 227 nm and 226 nm， respectively. FTIR spectra showed that three helix structures of ASC and PSC were well preserved. SDS-PAGE showed that ASC and PSC were type I collagen. And heat-denatured temperature of ASC and PSC were 52.24 ℃ and 49.65 ℃ respectively； SEM showed that the cross-linked fibrous network structure was formed in ASC and PSC； DHR showed that 1% ASC or PSC solution were mainly elastic at 0.1-10 Hz oscillation frequency and had a high gel stability.

Abstract:The molecular mechanism of the heat-induced cis / trans isomerization of non-conjugated linoleic acid （C18∶2） by alkali treatment and acid treatment was analyzed by gas chromatography with conventional heating as the control group. From the heating test， C18∶2-9c，12t and C18∶2-9t，12c are the main trans isomers in the heating of soybean oil. With the heating temperature gradually increased， the heating time gradually increased， the trans-linoleic acid content also increased， three kinds of oil samples after heating to produce trans fatty acids in the order： alkali treatment oil sample > acid treatment oil sample > Untreated oil sample. In the process of heating， the amount of monovalent linoleic acid produced is higher than the amount of bis-trans linoleic acid produced. When heated at 260 ℃ for 8 h， the amount of mono-functional linoleic acid （C18∶2-9c，12t） produced by heating oil after NaOH treatment， Up to 1.222%. It is found that C18∶2-9t and 12t are required to pass two energy barriers of 235.986 kJ/mol and 223.846 kJ/mol， respectively. The results showed that strong acid treatment or alkali treatment increased the chance of heating the trans isomers of oil， and the effect of strong alkali treatment was the strongest.

Abstract:Objective： This study aimed to extract polypeptide from the castoff of Thunnus alalunga and explore its protective effects on the damaged Chang liver cells induced by H2O2. Methods： The castoff of T. alalungawas pretreated for enzymatic hydrolysis. The optimal enzyme was screened using relative growth rate as the indicator. The optimal enzymolysis condition was determined by orthogonal tests. After hydrolysis， the resulting product was orderly purified by the ultrafiltration， ion exchange chromatography， gel filtration chromatography and reversed-phase high-performance liquid chromatography， and MTT method was used to evaluate the purification capacity for each step. The activities of AST and ALT enzymes were assayed by kit according to the manufacturer’s instruction. Inverted microscope and the flow cytometric analysis observation were used to investigate the effects of polypeptide addition on the apoptosis of Chang liver cells induced by H2O2. Results： The optimal enzyme for enzymolysis was trypsin， and its corresponding optimal hydrolysis condition was determined as follow： solid-liquid ratio was 1∶3， pH value was 9， enzyme dose was 900 U/g， temperature was maintained at 45 ℃ and held for 5 h. After a series of purification， pure polypeptide was harvested and its amino acid sequence was identified as Gly-Ala-Pro-Gly-Glu-Arg-Gly-Ser-Lys-Cys-Phe-Lys. With the addition of the identified polypeptide on Chang liver cells， the activities of ALT， AST， ADH and MDA were decreased but the activities of SOD were increased relative to control group without polypeptide during the period of H2O2 induction. The flow cytometry results demonstrated that the late apoptotic cell amount was significantly decreased relative to the control group. Conclusion： The identified T. alalunga polypeptide had a protective effect on the H2O2 induced Chang liver.

Abstract:Objective： To study the protective effect and mechanisms of hawthorn flavonoids on DNA damage of BRL-3A hepatocytes. Methods： MTT method was used to detect the effect of different concentration hawthorn flavonoids on hepatocytes injured by ethanol. Single-cell gel electrophoresis was used to observe the effect of hawthorn flavonoids on the DNA damage of hepatocytes and the Olive tail moment was measured. Physiological and biochemical indexes such as superoxide dismutase （SOD）， malonaldehyde （MDA） and glutathione peroxidase （GSH-Px） in cells were detected by kits. The mRNA expression of the gene SOD was measured by real-time quantitative polymerase chain reaction（qPCR）. Results： 0.2 mg/mL， 0.4 mg/mL and 0.8 mg/mL hawthorn flavonoids could significantly repair the growth and DNA damage of ethanol induced hepatocytes， which was closely related to the improvement of SOD， MDA and GSH-Px. Conclusion： Hawthorn flavonoids can be used to repair liver cells damaged by ethanol， and hawthorn flavonoids have potential for the treatment of liver injury.

Abstract:The effects of oat dietary fiber， rice protein and high-amylose corn starch on glycemic index after cooking and physical and chemical properties of extruded rice were studied. The results showed that the GI value of high-amylose corn starch extruded rice （HMER） after cooking was significantly lower than that of natural rice （P<0.05）， because the addition of high amylose corn starch promoted the formation of V-type starch crystals that are more difficult to hydrolyzed by enzyme. The GI values of oat dietary fiber extruded rice（DFER） and rice protein extruded rice （RPER） after cooking were higher than those of NR but slightly lower than that of extruded blank rice（ER）. The results of Infrared spectrum and X-ray diffraction showed that adding oat dietary fiber and high-amylose corn starch would promote starch retrogradation of extruded rice， while adding rice protein would inhibit starch retrogradation. HMER is similar to natural rice in transparency and color， while DFER and RPER are quite different from natural rice. Cooking properties and viscosity after cooking of HMER， DFER， RPER had no significant difference than that of extrusion blank rice （ER） （P>0.05）. The hardness of DFER and RPER after cooking was significantly lower than that of ER（P<0.05）， while the hardness of HMER and ER had no significant difference （P>0.05）.

Abstract:Soy protein， whey protein and casein are nutrient-rich protein sources. This study investigated the effects of three extrogenous proteins on the properties of reconstituted dough and the quality of Chinese steamed bread （CSB）. The Mixolab results indicated that soybean protein could significantly（P<0.05） increased the water absorption of dough， while whey protein reduced it， and casein had no obvious effect on water absorption. All three extrogenous proteins could significantly increase the dough stability time， and casein protein was the most effective， while whey protein had the least influence. Whey protein and casein have little effect on the starch gelatinization parameters in the dough， and the soybean protein have a significant effect on the peak torque C3 and retrogradation value. The effects of three kinds of extrogenous proteins on the dynamic rheological parameters of reconstructed dough have a certain effect. The soybean protein has the greatest influence on the elastic modulus （G′） and viscous modulus （G″） of the dough system， the casein followed， the whey protein has little effect on the G' and G″. In the aspect of CSB’s quality， the three proteins had a positive effect on the elastic parameter of the CSB. The 10% substitution value of whey protein had a positive effect on the flavor. All sensory evaluation data were more close to the control group when the substitution value of casein protein was 10%. The results of this study can lay the foundation for exploring the interaction between the protein and the key components of the dough.

Abstract:In this paper， response surface experiments according to the Box-Benhnken center combination principle was applied to optimize the extraction of polysaccharides from longan pulp by superfine grinding and enzymatic hydrolysis and the influencing factors as ultrasonic time， enzyme dosage and extraction time were evaluated； through the analysis of the basic composition， viscosity， polysaccharides solubility and molecular weight， physicochemical properties of longan polysaccharides（LP， LP-S， LP-SE） extracted by traditional hot water extraction， superfine grinding auxiliary extraction， superfine grinding and enzymatic hydrolysis auxiliary extraction were compared； the immune activity of longan polysaccharides （LP， LP-S， LP-SE） was compared by detecting the cytokines expression of macrophage. The results showed that ①The optimal technological parameters were conformed as follows： superfine grinding time 2 min， enzyme dosage 140 U/g， pH value 5， ratio of solid to liquid 1 ∶ 40， extraction temperature 50 ℃. Under these conditions， the experimental yield of polysaccharides was 38.49%； ②Compared to LP and LP-S， LP-SE had obvious differences including the higher yield， smaller molecular weight， lower viscosity and higher solubility， lower uronic acid， higher rhamnose and arabinose content； ③The ability of LP-SE to activate macrophages to secrete NO， IL-6， TNF-α， IL-1β， was significantly higher than that of LP and LP-S. The results indicated that the superfine grinding and enzymatic hydrolysis extraction can effectively change the physicochemical properties of polysaccharides and it showed the best immunoregulatory activity.

Abstract:To prevent the oxidation of EPA and DHA （54.79%） algae oil, Using whey separation protein, HI-CAP100 and malt dextrin （DE20） as wall material， the spray drying method was used to study its solid state， The optimum ratio of wall material and production conditions were determined with the embedding rate as the index， and the change of fatty acid composition of EPA algae oil in the curing process was studied. The experimental results show that the optimum proportion of HI-CAP100， whey separation protein and maltodextrin （DE20） was 2 ∶ 2 ∶ 1， the content of monoglyceride was 1%， the content of solid substance was 40%， and the homogenization condition was 35MPA three times. The air inlet temperature is 185-195 ℃ and the air outlet temperature is 90-100 ℃. When the oil load is 30%， the embedding rate is up to 97.03% and the oil load is 50%， the embedding rate is up to 92.88%. In the process of microcapsule preparation， EPA and DHA were only reduced by 1.021% and 1.327% respectively， indicating that the oxidation of PUFA was not obvious during the spray process， and the embedding effect was better.

Abstract:In order to commercialize Lactobacillus plantarum DMDL9010， the experiment was optimized by Plackett-Burman experiment and Box-Behnken experiment. This experiment mainly evaluated the safety of Lactobacillus plantarum DMDL9010 and provided the security for the production and application. Through harmful melabolite experiments， drug resistance experiments and other evaluation experiments determined the strains of bacteria as edible safety bacteria. The results showed that when the optimum dosage of Lactobacillus plantarum DMDL 9010 medium was 5 g/L of soybean polypeptide， 0.01% of vitamin C and 0.1565 g/L of manganese sulfate， the optimum dosage of Lactobacillus plantarum DMDL 9010 was 4.05×1010 CFU/mL， and the validation test was 3.88×1010 CFU/mL， which was close to the theoretical value. The safety evaluation experiments showed that the detection results of the harmful metabolites were all negative. Among the four common antibiotics， tetracycline， Mycin appears safe for the sensitive， erythromycin， amoxicillin showed safe and sensitive and contain no plasmid； Lactobacillus plantarum DMDL 9010 can inhibit the growth of E. coli， Staphylococcus aureus， Listeria monocytogenes； Did not produce hemolysis phenomenon. The results provide a reference for the commercial application of Lactobacillus plantarum DMDL 9010 in food field.

Abstract:The effects of fermentation time， fermentation temperature and salt content on amino acid nitrogen content and sensory quality of the cod bone hydralysate were studied. The volatile components of hydralysate were analyzed using electronic nose combined with headspace solid-phase microextraction （HS-SPME） and gas chromatography mass spectrometry （GC-MS）. The results showed that the optimum fermentation temperature， fermentation time and salt content were 35 ℃， 12 h and 15% respectively. The content of amino acid nitrogen and amino acid were 0.2685 g/100mL and 6 177.28 mg/100 g respectively， meanwhile the glutamic acid and aspartic acid which were umami amino acid were higher. The volatile compounds of hydralysate could be distinguished well by principal component analysis （PCA）； The aroma active compounds of the fermentation hydrolyzate were significantly increased by SPME/GC-MS and 18 kinds of aroma active compounds were detected， including 6 kinds of alcohols， 4 kinds of aldehydes， 3 kinds of pyrazines， 2 kinds of ketones， 2 kinds of furans and 1 kind of phenols.

Abstract:In this study， tilapia fish scales were hydrolyzed by alkaline protease. The effects of heat treatment temperature， time and substrate concentration on protein recovery （PR）， degree of hydrolysis （DH） and angiotensin converting enzyme （ACE） inhibition rate before and after enzymolysis were investigated. The relative molecular mass distribution of the heat treated fish skin before and after enzymolysis was also characterized. The optimal extraction conditions in this study were as follows： heat treatment temperature was 121 ℃， time was 15 min， and substrate concentration was 2%. Under this conditions， PR and DH was 65.93% and 10.54%， respectively. Compared with untreated samples， PR and DH under the optimal heating treatment conditions showed increases of 78.29% and 89.23%， respectively. The ACE inhibition ratio was up to 73.80%， which was 66.78% higher than that of untreated samples. The collagen-based peptides below 5 ku accounted for 99%， which covers below 1 ku with a ratio of 39.46%.

Abstract:The mixed solutions of soybean protein isolate（SPI） and maltodextrin （MD） were treated by ultrasound. The acid-induced gels were formed by the addition of glucono-δ-lactone （GDL）. The rheological property， microstructure， gel strength and water holding capacity were measured. Effect of ultrasonic treatment on the properties of SPI/MD mixture acid-induced gel was discussed. The crosslinking of protein aggregate could be promoted by addition of MD in SPI due to phase separation， forming more compact and uniform network structure， which resulted in the enhancement of gel network and the shortening of gel time. The ultrasonic treatment would transform the SPI/MD mixture gel from the chain structure to the granular structure， and the granular structure was more obvious with the extension of ultrasonic time. The ultrasonic treatment for 5 min could further enhance the network structure and the ability to resist destruction of SPI/MD mixture gels， and the gel network maintained better structural integrity. However， the ultrasonic treatment for 15 min and 25 min was not beneficial to the establishment of the mixture gel network， and there were large cracks in the microstructure of gels. The integrity of network structure was broken， leading to the decrease of gel strength and water holding capacity.

Abstract:Spray drying tower is a completely enclosed facilities， it is difficult to sampling analysis during the drying process. Oil-in-water （O/W） emulsions with gum arabic as wall material were prepared in this experiment. Single droplet drying （SDD） was been proposed that can simulate the environment of spray-drying， to studying the effects of the air velocities and the solids content in the emulsion on the surface formation mechanism of the particles by analysing morphological shrinkage and drying kinetics parameters of droplet during drying process. The results show that the drying behavior of droplets varies greatly at three air velocities of 0.70， 0.90， 1.10 m/s. When air velocities was 1.10 m/s， the moisture of droplet evaporates fastest， crust form earliest， the produced particles have smaller shrink rate. The total solids content of the emulsion also has an obvious effect on the drying behavior of the droplets. With the increase of the solid content， the water evaporation of the emulsion droplets decelerate， the crust form earlier， and the morphology of the resulting particle was larger. The experimental has guiding significance for studying the drying dynamic model and improvement spray drying product quality.

Abstract:Select Shewanella putrefaciens isolated from the fish as the research object， explored the effect of environmental factors including pH， aw and NaCl on its growth probability at room temperature （25 ℃）. The second order linear logistic regression equation and the PNN artificial neural network algorithm were used to establish the growth / non - growth interface model of Shewanella putrefaciens， the goodness of fit and the predictive power of the two models were compared and validated. The results showed that the coincidence rates were 93.80% and 100.00% of the trainingset and test set of the second order linear logistic regression equation which could predict the growth probability in detail； while the consistent rate of trainingset and test set of PNN artificial neural network is 100.00% and 86.67% and the optimal speed is 0.1 second， which can classify the growth / non-growth data. With the increasing of salt， the growth of Shewanella putrefaciens was inhibited， the growth interface moved to high water activity， high pH direction； The spoilage organism couldn’t grow under the condition of water activity of 0.91， aw=0.92， 0.94 and 0.96， growth probability of Shewanella putrefaciens increased with the increase of pH， rise steeply； while pH=4.5， Shewanella putrefaciens did not growth， with the increase of pH， the growth probability of high aw cases first reached 1. By developing the Shewanella putrefaciens growth / no growth interface model under different environment parameters， PNN artificial neural network model could make a good andrapid classification predictionon the growth / no growth data； The second order linear logistic model was better for the quantitative assessment of pH， aw and salt domains to protect the quality and the stability of products.

Abstract:The characteristics of protein degradation in Paralichthys olivaceus during refrigerated storage were investigated. The values of total volatile basic nitrogen（TVB-N）， TCA-soluble peptides， free amino acids， total viable count （TVC） and sensory evaluation were measured periodically， and the shelf-life model was established based on the protein degradation indicators. Results showed that the contents of TVB-N， TCA-soluble peptide， free amino acids， and TVC increased with the extension of storage time. The changes of the protein degradation indexes were more obvious in the samples stored at the higher temperatures. It was found that TVB-N， TCA-soluble peptide and TVC were well filtered by the first order reaction kinetics model （R2＞0.90）， while free amino acids was relatively good accordant with the first order reaction kinetics model （R2＞0.82）. Arrhenius equation was used to establish the dynamic models of protein degradation indexes with respect to storage time and temperature， and there was a higher fitting accuracy （R2＞0.9）. The relative error between the predicted and the actual values was within ±10%， which indicated that the established mathematical model could predict the quality change of fillets during storage in the range of -2 ℃ to 10 ℃.

Abstract:Fresh cut apple was dipped with kojic acid， ascorbic acid and citric acid for 3 min and stored at 4 ℃ for 9 days， The firmness， color， total phenol content， soluble quinine content， vitamin C content and polyphenol oxidase（PPO） activity were analyzed. Results showed that the effects of three organic acids treatments on the firmness and polyphenol oxidase activity of fresh cut apples were not significant （P>0.05）， but there were significant differences （P<0.05） of browning， total phenolics and vitamin C among different treatments. In conclusion， the three kinds of organic acid have inhibitory effect on browning of fresh cut apple， the effect of kojic acid treatment is better than that of citric acid and ascorbic acid， therefore， kojic acid is potentially a color preservative of fresh cut apple.

Abstract:The compound solution of plant essential oils were prepared by solvent agent and emulsifying two kinds of diluent carrier， and its quality was evaluated. The antibacterial activity was studied by measuring the minimum inhibitory concentration （MIC） and minimum bactericidal concentration （MBC）. Result showed that anhydrous ethanol as solvent agent can effectively improve the aqueous solubility of essential oils， but its overall antibacterial effect was less than 1，2-propylene glycol. The stable oil-in-water microemulsions could be fabricated using Tween-80 as a surfactant， anhydrous ethanol as a cosurfactant and oregano-thyme compound（1 ∶ 1） as an oil phase via construction of pseudo-ternary phase diagrams， which was a light yellow and transparent liquid. When the ratio of Tween 80 to anhydrous ethanol was equal to 3 ∶ 1， the system has the largest area of microemulsion region （29.55%） and the minimum dilution ratio （9 ∶ 1）. Characterized for its droplet size distribution， polydispersity index （PDI）， viscosity， Zeta potential， the microemulsion formula （10 ∶ 1 ∶ 28） was found to have the lowest droplet size（13.0nm ± 0.6nm）， the lowest PDI （0.231 ± 0.020） and optimal Zeta potential （-22.23mV ± 0.24mV）. Essential oil by emulsion have better resistance to salt， glucose， acid and alkali， as well as good storage stability. However， the antibacterial effect of microemulsion were found to be greatly weaken against the tested microorganisms. The research results provide a theoretical basis for the edible plant essential oils applied to the field of food preservation with its characteristics of high efficiency and safety.

Abstract:Aptamer has been applied for detection， separation / purification and clinic fields， because of many advantages such as stability， easy preparation， small molecular weight， simple storage and transportation. The traditional screening method always need complicated procedure and operation， and the mechanism of screening is still unclear. In the paper， based on computer-aided molecular modeling， the binding site of the known aptamer and 5' adenosine monophosphate（AMP） was studied， seven key bases were chosen to further mutate by wheel iteration orientation method. The new sequences were obtained by the comparation of the binding free energy step by step. After the fourth step， there were four new sequences （named as S1-S4） with high specificity were chosen. In the experiment， the best sequence（S4） and the initial sequence （S0） were identified by visual detection using colloidal gold. It was found that the experimental results were well agreement with the modeling results. It provides a basic platform to the optimal screening of the aptamer.

Abstract:Through Smell and HS-SPME-GC-MS analysis technology， the strain M5 which produce pleasant fruit flavor was screened. This flaver produced of strain M5 in the sorghum media which dealed with amyloglucosidase was best. The main aroma materials were the alkohol and esters. The ratio of β-phenylethyl alcohol on the total flavor components was 28.14%. The ethyl acetate quantity could reach to 26.5 g/L. The strain M5 was identificated by the method of molecular biology， the result showed that strain M5 was Geotrichum candidum. It was named G.candidum M5. Research showed strain M5 could grow in the condition of pH 3-6， temperature 25 ℃-40 ℃， alcohol 0%-18% （V/V）， sugar content 5%-35%. The optimal growth conditions of strain M5 was temperature 25 ℃ and pH 4.0. This study would supply the basis for the further utility on strain M5. And it would provide the species resources for the regulation on fermentation of Chinese Baijiu by the flavor-oriented technology， too.

Abstract:To study the effect of different amino-containing precursors to meat flavor formation， peptides fractions in molecular weights of <1 ku， 1-5 ku， and >5 ku， were separated from enzymatically hydrolyzed chicken by ultrafiltration， and the samples of free amino acids were prepared by hydrochloric acid hydrolysis of the enzymatically hydrolyzed chicken. A total of eight model thermal reactions subdivided into two types， i.e.， with or without the addition of oxidized chicken fat， were carried out using the samples of peptide fractions and the free amino acids， and glucose as reactants. For the reaction products， the absorbance at 420 nm and pH values were measured， and the volatile flavor compounds were analyzed by solid phase microextraction （SPME） and gas chromatography-mass spectrometry （GC-MS）. It showed that for both the two types of reactions， with the increase of molecular weight of the amino-containing samples， absorbance values at 420 nm and total amounts of volatile compounds were decreased. These might be due to the amino-containing precursors of larger molecular weights from the enzymatically hydrolyzed chicken possessing a lower reactivity. Among them， the free amino acid samples behaved the best in generation of sulfur-containing compounds， and the <1ku or 1-5 ku peptides samples behaved the best in generation of pyrazine compounds. On the other hand， because of affect of lipid degradation products especially carbonyls in the oxidized chicken fat on the Maillard reaction， when the oxidized chicken fat was added， absorbance values at 420 nm of the reaction solutions were slightly increased， whereas total amounts of volatile flavor compounds were considerably decreased. Meanwhile， amounts of some alkane chain compounds （e.g. 2-methyl-5-propylthiophene） were increased and a new alkane chain compound 2-butylpyridine emerged with the addition of the oxidized chicken fat.

Abstract:To determine the values of physico-chemical properties and potential risk factors including total volatile basic nitrogen， hydrogen sulfide， biogenic amines， benzoic acid， propionic acid and aflatoxins， in fermented soybean products， the experiment collected 59 products of soy sauce， douchi， sufu and bean paste in Chongqing. All of the samples showed normal pH and total acid content. Amino acid nitrogen contents of sufu and soy sauce samples had reached national standards. Biogenic amines were commonly existed in fermented soybean products especially tyramine and putrescine， but different samples contained different types of biogenic amines. Sufu contained the highest contents of total biogenic amines. Total volatile basic nitrogen might affect the safety of measured samples for its high contents. Hydrogen sulfide and aflatoxins were within safety limits. Benzoic acid and propionic acid were ubiquitous in all kinds of fermented soybean products. The contents of benzoic acid and propionic acid in some samples were much higher than national standards. Therefore， it is necessary to trace the change of risk factors during the processing and storage of fermented soybean products to propose effective control measures for quality and safety.

Abstract:Aflatoxin is a highly toxic and carcinogenic substance with UV fluorescence characteristics. To study the detection of aflatoxins by hyperspectral imaging， aflatoxin was collected by a hyperspectral imaging system at 365 nm UV light. A total of 250 peanut grain samples in the 33 bands（400-720 nm） hyperspectral images. A method for predicting aflatoxin content based on the histogram quantization features of hyperspectral image decomposition abundance images was proposed. The method first obtained aflatoxin end-band spectra by N-FINDR endmember extraction， Spectral images were subjected to non-negative matrix factorization（NMF） to get aflatoxin abundance images. Based on this image， histogram quantization features were constructed. Partial least squares regression （PLS） and support vector machine regression （SVR） Vegetation abundance inversion， 50% cross-validation method obtained the average relative error of the two regression models respectively 29.95% and 12.16%， RMSE up to 0.0306. The results of this study have positive significance for the optical rapid detection of aflatoxin in agricultural products.

Abstract:The current normal method for the determination of benzo（a）pyrene is not specific， and its sensitivity is not very good. The 3，4-benzo（a）pyrene（3，4-BaP） is an organic compound with the formula C20H12. 3，4-BaP is a harmful compound， because it generates carcinogenic and mutagenic metabolites which can intercalate into DNA and interference with transcription. In this study， the molecular imprinted sorbent was synthesized and packed into a solid-phase extraction （SPE） cartridge for the enrichment of 3，4-BaP in smoked sturgeon （Acipenser sinensis） bought from local market. An analytical method was also developed for accurate determination of 3，4-BaP on the basis of ultra-performance liquid chromatography tandem mass spectrometry. The molecular imprinted sorbents are dispersed spherical particles， with diameter from 20 to 90 μm. It was successfully applied in the enriching of 3，4-BaP， and its performance was compared with Sep-pak， HLB， and Florisil SPE. The method was validated， and the results showed that the calibration curve is linear with R2 = 0.9998. The limit of detection （LoD） and limit of quantitation （LoQ） are 0.98 and 3.16 μg/kg， respectively. The RSDs of intra-day and inter-day accuracy are 3.26%-4.77% and 3.78%-5.26%， respectively. The recovery ranged from 89.7% to 95.3%， with RSD 2.89%-3.44%. Afterwards， the method was successfully applied to determine the 3，4-BaP in 50 batches of smoked sturgeon. The results indicated that 12 positive samples were found. The content of 3，4-BaP in the worst sample reached 21.9 μg/kg. The contents of 3，4-BaP in the other samples are lower than 3.58 μg/kg. In conclusion， this method is good at determining 3，4-BaP in smoked sturgeon. The relevant data could be used as reference for the functional departments for ensuring the food safety for consumers.

Abstract:Shrimp paste， one of the Chinese traditional digesters， can promote the growth of anaerobic bacteria in intestines and balance the intestinal flora， which is beneficial to the intestinal digestion and absorption. Based on the Bohai shrimp paste as the research object， we isolated a strain of digestive bacteria in the shrimp paste with the nutrient agar medium， and found it positive by gram staining， 16S rDNA amplification and sequencing， BLAST alignment in NCBI databases and build strain phylogenetic tree showed it belonged to Bacillus licheniformis， which was consistent with the above characteristics. Heat resistance analysis of the strain found that there was no significant decrease on its survival rate at less than 40 ℃， and the survival rate was gradually decreased with temperature increasing， which indicated that the heat treatment in shrimp paste processing would attenuate its digestive activity. This study will provide a theoretical foundation for the digestive activity preservation of Bohai shrimp paste in food heating process.

Abstract:Eight bonito protein hydrolysates were prepared under different enzymatic hydrolysis processing with the index of protein recovery rate and bonito fish as raw materials. The xanthine oxidase（XOD） inhibitory activity， ORAC values， molecular weight distribution and the total contents of amino acid was measured. The correlation of XOD inhibitory activity and antioxidant activity of bonito protein hydrolysates with molecular weight distribution and the total contents of amino acid was constructed. The ultra-performance liquid chromatography-high resolution mass spectrometry （LC-MS/MS） was used to study the distribution of those peptides with XOD inhibitory activity and antioxidant activity. The results demonstrated that the correlation between XOD inhibitory activity and ORAC values was significant. The distribution of those peptides molecular weight <1 ku and the contents of aliphatic amino acids could be used to preliminarily evaluate the activities of bonito protein hydrolysates. After purification， the concentration of active peptides of fractions isolated from bonito protein hydrolysates was enhanced， and the total ion flow diagram of the purified fractions was related to the their uric-acid-lowering activity and antioxidant activity.

Abstract:Volatile compounds of navel orange in Gannan and other areas by gas chromatography-mass spectrometry （GC-MS）， and the metabolomics of navel orange in different areas was studied， which provided scientific basis for quality assurance of Gannan navel orange. The volatile components of navel orange were analyzed by GC-MS and identified by database matching with the relevant reports. The potential biomarkers were screened by the s-plot of orthogonal partial least squares discriminant analysis （OPLS-DA） and the variable importance in the projection value （VIP>1， P<0.05）. The results showed that 66 volatile components were identified in Gannan navel orange， which were terpenes， aldehydes， alcohols， esters and ketones， the highest content was D-limonene. The five volatile components were （1S）-（+）-3-Carene，4-Carene， nonanal， （Z）-Caryophyllene， Eudesma-3，7（11）-diene， which can serve as potential biomarkers for the distinction between navel orange and other regions of the navel orange.

Abstract:In this study， thirty fermented vegetables samples were collected from Baisha， Changjiang， Qiongzhong， Lingao， Wenchang， Wanning， Wuzhishang areas， Hainan province. Types of fermented vegetables includes fermented bamboo shoots， fermented watermelon， fermented cabbage and fermented bean. Traditional methods of isolation and culture， 16S rRNA sequence analysis and qPCR were appealed to isolate， identify and describe the diversity of microorganisms in the samples. Three genus and sixteen species were identified， Lactobacillus accounted for 84.30% of the total， Enterococcus and Pediococcus were 15.12% and 0.58%. Then， Lactobacillus average gene copy number in each sample was 3.39×107， Enterococcus was 5.89×105 and Pediococcus was 8.71×103. Consequently， Lactobacillus was the most predominant genus， and Lactobacillus plantarum was predominant specie. There were also differences in microbial diversity in different regions and different kinds of fermented vegetables. This study preliminarily revealed the diversity of microorganisms in fermented vegetables in Hainan， which laid the foundation for further research and utilization of microbial resources in this area.

Abstract:The malondialdehyde （MDA）， oxymyoglobin （OMb）， metmyoglobin （MMb）， antioxidant enzymes activity （superoxide dismutase SOD； catalase CAT； glutathione peroxidase GSH-Px）， antioxidant ability （cupric reducing antioxidant capacity CUPRAC； radical scavenging ability RSA）， color and pH were determined to analyze the difference of antioxidant system in biceps femoris muscle （BF）， triceps brachii muscle （TB）， and longissimus dorsi muscles （LD） from Sunit sheep. The results showed that the SOD and CAT in TB were highest， while the CAT， CUPRAC， RSA in LD was highest. The pH in LD was highest， while the MDA， L*， a* and b* of LD were significantly lower than BF and TB （P<0.05）. The content of OMb in BF was significantly higher than TB and LD （P<0.05）， while the content of MMb was significantly lower than TB and LD （P<0.05）. The antioxidant enzymes in the muscles of Sunit sheep have synergistic effects， and the enhancement of antioxidant enzyme activity will improve the antioxidant ability and reduce the oxidation degree. Overall， the antioxidant substances content， the ability to remove free radicalsin and CAT in LD were highest； lipid oxidation degree was lower than BF and TB. Consequently， the LD has higher antioxidant ability than BF and TB.

Abstract:Milk protein is the main index to determine the nutritional quality of milk， while thermal processing will affect the stability of whey proteins， especially β-lactoglobulin. With the heat treatment temperature， whey protein denaturation， self-aggregation occurs. The dimeric structure of β-lactoglobulin expands and binds to α-lactalbumin. Negatively charged lactoferrin binds positively charged β-lactoglobulin， bovine serum albumin， and immunoglobulin G. In the meantime， β-lactoglobulin undergoes sulfhydryl-disulfide exchange with κ-casein and milk fat globule protein. In addition， whey protein and lactose glycosylation reaction. Whey protein and calcium through ionselectrostatic groups binding force. Whey protein through the disulfide bond with the milk fat aggregation reaction. All of the above reactions affect the thermal stability of the dairy product， ultimately affecting the quality of the product. In this paper， the thermal induced polymerization and its pathway of whey protein were investigated， and the process and mechanism of interaction between whey proteins and other milk components were clarified. It will contribute to control the interaction of milk composition system during processing， and has important theoretical significance to improve the thermal stability， gel， water holding capacity and other functional properties of dairy products. Broaden whey protein as an ingredient in the application of food systems.