Abstract:Enzyme preparations are widely used in the food industry， and they have the characteristics of environmental protection and sustainable development. However， harsh industrial processing conditions severely restrict the wide application of enzymes in the food industry. Aiming at the drawbacks of poor stability and low catalytic activity of natural enzymes under industrial application， computer-assisted protein design is one of the commonly used strategies to obtain enzymes with excellent performance. In this paper， the classification and development of the current food industrial enzymes are first reviewed. Then， in silico methods adopted for protein engineering are also provided. Finally， the application of computational simulation techniques in improving thermal stability， pH stability and catalytic efficiency was introduced.

Abstract:In this research， the metabolism sites of chlorophyll and its derivatives in rats were studied by 24 hour metabolism experiment. Under acid conditions， in stomach， Chlorophyll a would be immediately degraded into pheophytin a， accompanying with production of a little amount of chlorophylide， while Chlorophyll b was relatively stable. Chlorophyll was rarely absorbed in the rats’ stomachs； the amount of entry in large intestine were relatively around 84%， and the excrement rate in the feces was about 43%， whereas nothing was detected in the blood and urine. The results of analysis of gut microbiota and their metabolites showed that the ingestion of chlorophyll changed the composition and abundance in the sequencing of the fecal microbiota. The relative abundance of Proteobacteria was significantly reduced， while Akkermansia and Lactobaillus were significantly increased. And chlorophyll promoted the increase of acetic acid， propionic acid and citric acid.

Abstract:In this paper， the effects of two high F oligopeptides， M2 and M3， which were prepared from tuna minced meat and purified， on the intestinal flora structure of mice were investigated. By intragastric solutions of M2 and M3， intestinal contents of mice were collected， and DNA was extracted for 16s rRNA sequencing. Species composition and abundance distribution of intestinal flora of mice were analyzed using Anosim， OTUvenn， OUT PCA， PCoA and LDA EffectSize. The results showed that the intestinal microflora structure of the mice in the three groups was different， but the microflora of the two oligopeptides groups were less different， and the composition of the microflora of the blank group was significantly different. The total amount of bacteroidetes and firmicutes in the two oligopeptides groups was 90.17% and 91.73%， respectively， both higher than 88.20% in the blank group. At the level of the two oligopeptides， the dominant bacteria were spirillaceae， riken and prevotella， while the blank group was plasmodiaceae. The dominant characteristic bacteria of the M2 oligopeptide group were the invisible corpuscular family， the dominant characteristic bacteria of the M3 oligopeptide group were the rikenellaceae， mycobacterium and the methylobacteriaceae， and the dominant characteristic bacteria of the blank group were the purple single cells and moraxaceae. The results indicated that high F value oligopeptides M2 and M3 could regulate the structure of intestinal flora of mice， promote the proliferation of beneficial bacteria， and thus improve the intestinal microecology of inflammatory mice， laying a foundation for the subsequent study on the anti-inflammation activity of the high F oligopeptin M3.

Abstract:The protective effect of Lactobacillus plantarum CP234 isolated from Shanxi aged vinegar on nonalcoholic fatty liver disease（NAFLD） in rats were investigated. Oral administration of L. plantarum CP234 significantly decreased the levels of serum total cholesterol（TC）， low-density lipoprotein cholesterol（LDL-C） and triglyceride（TG）in rats with high fat diet induced NAFLD. Also， the lipid profile of liver were significantly changed. Serum alanine transaminase （ALT） and aspartate aminotransferase （AST） were decreased， meanwhile， superoxide dismutase （SOD） and glutathion reductase （GSH） in liver were enhanced， which recovered and improved the oxidative stress ability and function of liver. The fluorescence quantitative PCR results suggested that downregulating lipogenesis （PPAR-γ、FAS and ACC-1） and upregulating genes expression related to lipolysis were also involved in the beneficial effect of L. plantarum CP234 on NAFLD. Furtherly， the effect of L. plantarum CP234 on intestinal floras and fecal pH and water content were studied.

Abstract:Acrylamide（AA）， a hazardous substance， was classified AA as group 2A carcinogen， and common in fried and baked foods. At present， most studies focus on how to reduce production of AA in the processing， and it may be another new idea to reduce its harm after its production. The aim of this paper is to explore the protective effect of CCA against AA-induced oxidative in zebrafish embryos. Survival rates， reactive oxygen species （ROS） and malondialdehyde（MDA）， antioxidant enzymes including catalase （CAT）， superoxide dismutase （SOD）， glutathione peroxidase （GSH-Px） and the mRNA expression levels were determined. Results revealed that AA exposure led to oxidative stress characterized by significant increase in ROS and MDA （P＜0.05）. However， compared with AA group， CCA improved the survival rates and the activities of antioxidant enzymes while decreased MDA and ROS levels caused by AA（P＜0.05）. In conclusion， CCA can protect zebrafish embryos from AA-induced oxidative stress.

Abstract:Objective： To investigate the effect of fruits and vegetables on hypertension. Methods： 5 kinds of fruits and vegetables （broccoli， garlic， spinach， oyster mushroom and kiwifruit） were selected for inhibiting angiotensin converting enzyme （ACE） activity on the basis of pre-experiment. The experiments of water extraction， pepsin hydrolysate and ethanol extraction of samples， and mutual mixing and simulated body digestion inhibiting the activity of ACE was carried out. The content of hippuric acid was detected by high performance liquid chromatography （HPLC） to respond the effect of the extracts on the activity of ACE. Result： The water-soluble substances and pepsin hydrolysate of fruits and vegetables significantly inhibited the ACE activity， whereas some ethanol extracts could promote the ACE activity. Moreover， the water extracts of kiwifruit， Pleurotus ostreatus and pepsin hydrolysates of garlic and spinach strongly inhibited ACE activity. Both of water extract and pepsin hydrolysate of broccoli strongly inhibited the activity of ACE， but the inhibitory effect of its aqueous extract decreased greatly after dilution. The polypeptide of broccoli might have the strongest ability to inhibit ACE activity. Triple mixing compound of the pepsin hydrolysates of broccoli， garlic and spinach has synergistic effect. The water extracts of kiwifruit and Pleurotus ostreatus combined with spinach pepsin hydrolysates also had synergistic effect， whereas the water extracts of kiwifruit and Pleurotus ostreatus had antagonism with the pepsin hydrolysates of garlic and broccoli. The pepsin hydrolysates of broccoli， garlic and spinach remained high ACE inhibitory activity after simulated digestion. Broccoli polypeptide showed the strongest anti-digestibility. Conclusion： Most fruits and vegetables have both lowering and raising blood pressure substances. Its lowering blood pressure ability was stronger than raising. Polypeptide might be the main substances in fruits and vegetables that lower blood pressure. There are some water-soluble lowing hypertension substances， while some weak polarity substances might play a role in raising blood pressure. Thus， some good antihypertensive fruits and vegetables -based foods may help lower high blood pressure.

Abstract:Natural rice protein was modified by enzymatic reaction（trypsin， pH 8.0， 55 ℃） at different times to prepare rice protein hydrolysates with different degrees of hydrolysis（2%， 4% and 8%）. The effects of different degrees of hydrolysis on the secondary structure， micromorphology， thermal behaviors， intrinsic fluorescence， surface hydrophobicity， sulfhydryl content， solubility， emulsifying properties and in vitro antioxidant activity were investigated. The results showed that the content of β-turn in rice protein hydrolysates was increased， indicating a more stretchable and flexible secondary structure. The microstructure was observed to be porous， which is beneficial to improve solubility and emulsifying properties. When the degree of hydrolysis is less than 4%， the hydrolysates exhibited a good thermal stability； as the degree of hydrolysis increased， the heat resistance decreased. The enzymatic process also caused a change in the chromophore content of the protein molecule and a stronger fluorescence intensity as the degree of hydrolysis increased. In addition， the surface hydrophobicity and sulfhydryl content of rice protein decreased first and then increased after enzymatic hydrolysis， which may be related to the folding and unfolding caused by the change of disulfide bond of protein molecule. The study also found that the antioxidant activity of the enzymatic hydrolysates was significantly improved compared with the natural rice protein. The DPPH and ABTS free radical scavenging rate was the same as that of the BHT at the same concentration. As a mild， safe and efficient modification method， restrictive enzymatic hydrolysis can greatly improve the structure and functional properties of rice protein and significantly improve its antioxidant activity in vitro.

Abstract:The marine protein oligopeptides were obtained by complex enzymatic hydrolysis method， and their physicochemical properties， amino acid composition and molecular weight distribution were analyzed. The antioxidant activity of marine protein oligopeptides was analyzed from four aspects including hydroxyl radicals， DPPH free radicals， superoxide anion radical scavenging ability and reducing ability. In addition， from the ACE inhibitory activity， their ability to lower blood pressure was explored. Marine protein oligopeptides had strong in vitro antioxidant capacity， and the semi-inhibitory concentrations （IC50 values） of hydroxyl radicals， DPPH free radicals and superoxide anion radicals were approximately 2.75， 4.7 mg/mL and 18.2 mg/mL， respectively. The reducing ability at the concentration of 20 mg/mL was equivalent to the ascorbic acid VC concentration of 0.04 mg/mL. In addition， marine protein oligopeptides showed a higher ACE inhibitory ability with the IC50 value of approximately 0.75 mg/mL. This experiment clarified that marine protein oligopeptides have good anti-oxidation and antihypertensive activities， which provided a certain reference basis for the development and utilization of nutrition and health food.

Abstract:The GES-1 cell injury model was induced by indomethacin to study the protective effect of polysaccharides and fruiting body polysaccharides of Hericium erinaceus on gastric mucosa. The extraction process of crude polysaccharides from Hericium erinaceus was optimized by water extraction and alcohol precipitation extraction method， and the difference of polysaccharides on gastric mucosa protection before and after purification was explored at the cellular level. Studies have shown that the crude polysaccharides of the mycelium of Hericium erinaceus and the crude polysaccharides of the fruiting bodies have obvious proliferative effects on GES-1 cells， and can significantly improve the survival rate of damaged GES-1 cells. The optimum conditions for the purification of crude polysaccharides from Hericium erinaceus were as follows： the ratio of solid to liquid was 1 ∶ 15， the extraction temperature was 80 ℃， and the extraction time was 2 h. Under these conditions， the purity of mycelium polysaccharide increased from 40% to 50%， the purity of fruiting body polysaccharide increased from 35% to 42%， and the survival rate of damaged GES-1 cells also increased significantly. The results indicated that the mycelium polysaccharides and fruiting body polysaccharides from Hericium erinaceus have good protective effects on gastric mucosa.

Abstract:Objective： To clone and recombinantly express ornithine transcarbamoylase from Lactobacillus brevis and study its enzymatic properties. Methods： The gene cloning process was using Lactobacillus brevis as template which based on the gene sequence analysis. The recombinant protein was expressed in E. coli， and purified by Ni-NTA affinity chromatography column. By using arginine as substrate， the enzymatic properties were studied. Results： The optimal temperature of recombinant ornithine transcarbamoylase is 55 °C. It has excellent thermal stability at 4 °C and still retains more than 50% biological activity at 37 °C for 3 hours. However， after 40 minutes at 65 °C it will totally lose activity； the optimal pH value of the enzyme is 6.5， when the pH is alkaline， the enzyme activity decreases significantly； the enzyme possess highest activity under 5% mass fraction of NaCl and 5% volume fraction of ethanol， but the difference is not obvious， indicating recombinant ornithine transcarbamoylase has good salt tolerance and alcohol tolerance； the kinetic parameters Km is 1.58 mmol and Vmax is 5.88 mmol/min. Conclusion： The ornithine transcarbamoylase derived from Lactobacillus brevis has good temperature stability， salt tolerance and alcohol tolerance， and has certain application prospects in alcohol fermentation.

Abstract:In this paper， cod skin gelatin was used as raw material， and the effect of xylitol， sucralose， stevioside， sucrose on the physical， rheological， functional characteristics and Raman spectrum of fish skin gelatin was studied. Results indicated that sweeteners/ sucrose can improve the gel strength， hardness， thermal denaturation temperature and enthalpy of gel products. The results of rheology and functional properties showed that the sweeteners/sucrose could make the gel samples have higher G′， G″， foaming property and water holding capacity. Raman spectra illustrated that the protein secondary structure of the mixed system was transformed random coil into α-helix， which made the system more stable. Therefore， low-calorie sweeteners could be as the sugar replacers applied to food industry.

Abstract:Antarctic krill is an important source of phospholipids， which is also a natural storage for phospholipid bioaccumulation. In this study， the phospholipids from Antarctic krill was extracted by enzyme-assisted Bligh & Dyer extraction. The influcing factors of the extraction rate， such as temperature， pH value， enzymatic hydrolysis time and the kind of enzyme were investigated. The structure composition of fatty acids was assayed by gas chromatography with the quantification and analytical identification of phospholipids by HILIC-QTOF/MS. An optimum phospholipid extractants of （3.66 ± 0.03）% was obtained by the typsin， the extraction temperature of 41 ℃， the pH value of 9 and the extraction time of 3 h. The main structure of fatty acid chains were C16:0 （31.58%）， EPA （31.94%）， DHA （20.64%）. Under the enzyme-assisted Bligh & Dyer extraction， the content of EPA and DHA chains were up to 52.58% with the higher percentage of unsaturated fatty acids. Three kinds of phospholipids， including Phosphatidyl cholines（PC）， Phosphatidyl ethanolamine （PE） and Phosphatidylinositol （PI）， were successfully separated by HILIC-QTOF/MS. After the ion source separation， 59 kinds of phospholipid molecules were totally detected， while the structure information of fatty acid chains were identified by database and secondary mass spectrometry. The results revealed that an abundance of EPA and DHA chains were existed in phospholipid molecules from Antarctic krill. In conclusion， this study provided the foundation for the development and utilization of Antarctic krill phospholipids.

Abstract:Perca fluviatilis were treated by different treatments （soaking in water or 3 mg/mL garlic powder solution， boiled with distilled water or 3 mg/mL garlic powder solution） and the content of adenine， guanine， hypoxanthine， xanthine and total purine were determined using high performance liquid chromatogram（HCLP） method. The results showed that boiling treatment could effectively decrease the content of total purines， by contrast， the effect of soaking treatment was not obvious. The removal rates of purine increased after adding 3 mg/mL garlic powder in the boiling treatment as well as the group of soaking treatment purine content was lower than that in blank group. The highest removal rate of total purine in Perca fluviatilis was obtained by boiling 3 mg/mL garlic powder solution， which was followed by boiling in water， soak in 3 mg/mL garlic powder solution and soak in water. The results showed that the purine content of the sample decreased， when the boiling time was 12 minutes， while the taste was guaranteed.

Abstract:In this paper， Fourier Transform infrared spectroscopy（FTIR） was used to study the changes of gluten protein structure when the amount of rice bran dietary fiber powder obtained by Ultra high pressure homogenization（UH-PH）was 0%， 5.0%， 10.0%， 15.0%， and 20.0%. The results showed that the secondary structure of gluten protein supplemented with rice bran dietary fiber powder was still dominated by α-helix and β-sheet. However， as the amount of dietary fiber powder added to rice bran increased， the content of α-helix structure was significantly reduced（P＜0.05）， the decreasing trend of the total content of β-turn and random coils was the same as the increasing trend of the β-sheet content， both decreased first and then increased， that is， they all showed the tendency of β-turn and random coils transformed to β-sheet. When the amount of rice bran dietary fiber nano-powder was more than 15%， the α-helix content in the secondary structure of gluten decreased sharply， the hydrogen bonds in the space conformation of gluten protein were destroyed， and the protein helix structure was seriously damaged， the balance of maintaining the gluten protein’s spatial stability was destroyed， the structure of the gluten protein tended to loosen. Therefore， when the amount of rice bran dietary fiber powder is controlled within 15%， the pasta products can obtain good processing characteristics while having a health care function. It can be seen that ultra high pressure homogenization treatment is beneficial to the micronization of rice bran dietary fiber， which can improve the comprehensive utilization of rice bran.

Abstract:To provide a theoretical basis for optimizing the quality characteristics of millet starch， millet starch and its whole powder were treated under pressure of 300， 450 MPa and 600 MPa for 20 min to investigate the effects of different high static pressure treatment on the structure and gelatinization properties of millet starch and the starch of its whole powder. The results showed that the millet starch swelled significantly at higher pressure levels， and weak gel was formed between the particles. The viscosity did not change a lot， and the disintegration value and the regenerative value decreased. The starch of millet whole powder was complexed with surface substance at a higher pressure level， and the disintegration value decreased but the regenerative value increased. This indicated that high static pressure could improve the particle structure and gelatinization properties of millet starch and its whole powder to some extent.

Abstract:Eight strains of probiotics with clear source and good functional characteristics were used to prepare lactic acid bacteria beverage with different fermentation materials. To explore the fermentation characteristics of compound probiotics and its effects on antioxidant， pathogenic bacteria and blood pressure lowering ability of lactic acid bacteria beverage with different base materials， Principal Component Analysis （PCA） was used to evaluate the functional characteristics of lactic acid bacteria beverage during storage period comprehensively. The results showed that the growth rate of compound probiotics in skim milk was the fastest and the number of live bacteria was the highest when it reached the stable stage. The change of acidity was consistent with the growth curve. In the comparison of the specific functional characteristics of lactic acid bacteria beverage， the whole functional characteristics of the beverage with skim milk powder as the base material was the strongest， the lactic acid bacteria beverage with soybean separated protein powder as the base material had stronger ability of inhibiting pathogenic bacteria， anti-oxidation and blood pressure lowering ability of Lactobacillus beverage based on whey protein powder is stronger. The information of three principal components reflecting the original variables was extracted by principal component analysis， and the cumulative contribution rate was 95.589， which could reflect the change trend of 9 functional indexes. The results showed that different storage time had an effect on the functional characteristics of lactic acid bacteria beverage. The comprehensive scores of the functional characteristics of different base material lactic acid bacteria beverages during storage were as follows： skim milk powder>soybean separated protein powder>whey protein powder.

Abstract:The borage oil was encapsulated using three groups of wall materials by spray drying method， the physicochemical properties， stability and in vitro release behavior of three different borage oil microcapsules were evaluated. The results showed that compared with the other two borage oil microcapsules， the encapsulation rate of borage oil microcapsules made of sodium casein and gelatin and corn syrup was the highest， up to 95.7%， and the particle size was the smallest （264.09 nm）. The apparent structure of microcapsules is more complete and uniform. Meanwhile， differential scanning calorimetry， thermal analysis and accelerated storage experiments revealed that borage oil microcapsules presented the best protection against heat and oxidation， and the core material total release rate of borage oil microcapsules in gastrin-intestinal was also the largest after in vitro digestion（82.47%）. Therefore， the formulation is more suitable than the other two formulations to prepare borage oil microcapsules with high stability and high in vitro digestion release rate. Microencapsulated borage oil contributes to the absorption of the active components of functional oils in the human body， which is more suitable for food industry applications.

Abstract:In this paper， the effects of different hot air drying temperatures （40， 60， 80， 100， 120 ℃） on drying kinetics， color， water activity， polyphenol content and antioxidant capacity （DPPH， FRAP） of ice plant were studied with freeze-drying considered as the control treatment. The results showed that the drying time for ice plant was shorter as the temperature increase. SLogistic1 model equation was found as the best fit at various temperatures， and the correlation coefficient （R2） was highest （>0.970）. The total phenols， total flavonoids and antioxidant activities in ice plant increased with the increase of drying temperature （40-80 ℃）. However， total phenols， total flavonoids and antioxidant activities decreased when the temperature higher than 80 ℃. And the DPPH and FRAP values of ice plant dried by 80 ℃ hot air were 24.3 mg TE/g dw and 105.0 mg TE/g dw， respectively. Furthermore， the content of protocatechuic acid， chlorogenic acid， caffeic acid， cumaric acid and ferulic acid in ice plant dried at 80 ℃ were significantly higher than those of other hot air drying temperature. On the other hand， ice plant dried by 80 ℃ hot air showed the lowest color differences compared with their freeze-dried counterpart. As a result， hot air-drying at 80 ℃ was a recommended drying method for ice plant.

Abstract:The effects of ultra-high pressure， ultra-high pressure time and ultrasonic time on the quality and antioxidant activity of strawberry slices were studied. The results showed that ultra-high pressure combined with ultrasonic pretreatment can significantly improve the quality （color and hardness） of vacuum freeze-dried strawberry slices， and promote the water diffusion during the drying process of strawberry slices. In addition， the antioxidant activity of freeze-dried strawberry slices has been significantly improved after ultra-high pressure combined with ultrasonic pretreatment （P＜0.05）. The optimal pretreatment conditions are as follows： ultra-high pressure of 100 MPa， ultra-high pressure time of 5 min， and the ultrasonic time of 25 min， the hardness， a* value， anthocyanin content， total phenolics and flavonoids content of strawberry slices were 707.28 g， 31.01， 304.39 mg/kg， 11.60 mg/100 g and 221.41 mg/100 g， respectively.

Abstract:In order to explore the inactivation mechanism of electron beam irradiation against Listeria， the effects of intracellular components and related gene expression on Listeria were studied by fourier transform infrared spectroscopy and real-time fluorescence quantitative PCR. The results showed that after the electron beam irradiation， the absorption peak intensity of the intracellular components of Listeria decreased， and the absorption frequency shifted， which resulted in the changes of the structure and conformation of intracellular membrane fatty acids， proteins， nucleic acids and other substances. And in the amide I band the content of α-helix and β-turn was significantly reduced， and the content of β-sheet and random coil were significantly increased， indicating that the intracellular protein structure became disorder after irradiation. In addition， electron beam irradiation treatment resulted in the elevations of recA gene and glucose metabolism related genes， while reductions in the level of virulence factors. The above results indicated that electron beam irradiation had significant effects on the intracellular components and the related genes expression of Listeria， and these changes may play an important role in the death of L. innocua caused by electron beam irradiation.

Abstract:To explore the effects of continuous sterilization at low temperature on the quality of canned citrus， Satsuma mandarin was chose as raw material， sterilized canned citrus through the continuous water bath sterilization machine， recorded the time required to achieve commercial sterility at different sterilization temperatures， and measured the changes of canned citrus flesh color， texture and vitamin C， total sugar， soluble solids， flavonoids and other nutrients under different sterilization conditions. The results showed that： 1） The time required for canned citrus to be commercially sterile decreased with the increase of temperature. 2） The color of citrus flesh changed significantly under different sterilization conditions， the sterilization condition of the best color was 80 ℃， and the L*， a* and b* values were 43.02， 9.62 and 18.88， respectively. At the same time， the browning degree of citrus flesh deepened under the sterilization condition of 100 ℃， and the hardness， adhesion， chewability， elasticity and fracture of citrus flesh were also decreased by high temperature. 3） In the process of sterilization， with the increase of temperature， the content of vitamin C， total sugar， hesperidin， naringin and didymin in citrus flesh all decreased significantly， compared with the unsterilized group， the maximum reduction was 18.10%， 17.66%， 22.49%， 16.68% and 27.21%， respectively. Therefore， the low temperature （80 ℃） sterilization was more conducive to maintaining the color， texture and nutritional quality of canned citrus.

Abstract:Objective： UPLC-MS technology was used to study the metabolic characteristics of fermented milk during storage， and the quality of fermented milk during storage was evaluated by the perspective of metabolisms， which in order to provide effective basis for industrialized production and control the quality of S. thermophilus S10 fermentation milk. Method： Collected fermented milk for 0， 1， 7， 14， 21 d of storage. The metabolic fingerprint of fermented milk was established based on ultra high performance liquid chromatography - quadrupole time of flight mass spectrometry （UPLC-QTOF MS）. The data were preprocessed with the software MarkerLynx， and analyzed by principle component analysis， and orthogonal signal correction partial least squares discrimination analysis. Results： Potential biomarkers were screened out according to database searching and MS information matching. A total of 22 metabolites including Glycyl-L-valine， succinic acid， oxaloacetate， glycine， L-glutamic acid， nicotinic acid were identified inset fermented milk during different storage times. These potential biomarkers relate to several metabolic pathways such as carbohydrate and energy metabolism， nucleotide metabolism and amino acid metabolism. Conclusion： The differential metabolites involved in the metabolic characteristics of S. thermophilus S10 fermented milk were mostly primary metabolites， which type and content do not have an adverse impact on the quality of the fermented milk.

Abstract:As the market for healthy foods has grown rapidly， the demand for brown rice noodles has been increasing due to its nutritional and health-functional properties， but the extremely short shelf-life severely restricts its industrial production. Radio Frequency （RF） is widely used in food sterilization. This study explores the effects of RF treatment on the quality and storage stability of fresh brown rice noodles. The study showed that the total plate count （TPC） and the molds and yeasts （MY） counts of the 130 mm/ 20 min RF treatment group decreased by 2.50 and 2.17 lgarithms， respectively. The shelf life of the 120 mm/ 15 min， 130 mm/ 15 min， 130 mm/ 20 min RF treatment group was extended from less than 1 day to 3 days. At the same time， RF treatment can effectively inhibit the fatty rancidity of fresh brown rice noodles： the fatty acid （16.90 mg/ 100 g） of the 130 mm/ 15 min RF treatment group was significantly lower than the blank group （36.1 mg/ 100 g） when stored for 3 days. In addition， RF treatment could effectively delay the decrease of pH， the increase of fatty acids and the deterioration of cooking quality of fresh brown rice noodles during storage. However， high-intensity RF treatment might cause some bad effects on fresh brown rice noodles such as water loss， browning， the increase of hardness and broken rate. When the plate spacing is 130 mm and the sterilization time is 15 min， the number of spoilage microorganisms can be effectively reduced and the original quality of fresh brown rice noodles can be maintained to the utmost.

Abstract:To study the effects of tea polyphenols， 1-methylcyclopropene （1-MCP） and their compound treatments on the quality changes of yellow kiwifruit after harvest. Yellow kiwifruit from Pujiang River， Sichuan Province was used as the test material. First， Fruits were treated with 1-MCP for 24 h， then coated with 0.7% tea polyphenols for normal temperature storage test. During storage， the changes of hardness， weight loss， color difference b value， respiratory intensity， ethylene release， vitamin C content， chlorophyll content， pectin content， polyhemicuronidase， pectin methyl esterase and pectin lyase activity were analyzed. The results show that the compound treatment could prolong the storage period of kiwifruit， keep the better color of the fruit， reduce the weight loss rate and delay the appearance of the peak of respiration and ethylene release at room temperature. And delaying the consumption of nutrients and maintaining the sensory quality of kiwifruit. Comprehensive analysis shows that the compound fresh-keeping treatment has good effect of keeping fresh.

Abstract:In this study， a solid phase micro-extraction coupled with gas chromatography tandem mass spectrometry （SPME-GC-MS/MS） method was established for the analysis of 9 aromatics （toluene， ethylbenzene， o/p/m-xylene， 1，2，4，5-tetramethylbenzene， naphthalene， 1-methylnaphthalene， 2-methylnaphthalene） in food contact silicone products. The contents of 9 aromatics in 31 nipples and 32 molds were determined and analysis. Suppose that 9 aromatics could completely to food， a simple distribution assessment model was established by the @RISK to calculate the estimated daily intake of 9 aromatics in the molds and nipples. Finally， through the exposure assessment combined with the existing regulations at home and abroad， the preliminary safety assessment was carried out. The results indicated that the analysis method was efficient， sensitive and reliable. The detection limit of 9 aromatics ranged from 6.30×10-3 to 0.06 ng/mL， and the average recovery rate from 98.24% to 110.23%. The average content of 9 aromatics was 6.91-129.79 ng/g in 31 nipples and 50.73-1 376.78 ng/dm2 in 32 molds， respectively. In the case of hypothetical extreme migration， the estimated daily intake of 9 aromatics was 1.06-21.63 ng/kg bw in 31 nipples and 0.47-12.63 ng/kg bw in 32 molds， which were lower than the EU limits. The results indicated that the migration of 9 aromatics may result in less safety risks.

Abstract:Objective： The minimum inhibitory concentrations （MICs） for 15 antibiotics of 20 Bifidobacterium isolates were determined and the transfer of antibiotic-resistance genes was assayed. Methods： 20 strains of Bifidobacterium strains were tested for the minimum inhibitory concentration of 15 antibiotics by broth dilution method， and the specific primers were used to detect whether the strain contained drug resistance genes by polymerase chain reaction. Finally， the drug resistance gene transferred was tested by filter hybridization. Results： The MIC values varied significantly among the Bifidobacterium isolates， including those of the same species. All of the Bifidobacterium isolates were susceptible to ampicillin， gentamicin， streptomycin， and linezolid and intrinsically resistant to kanamycin； in contrast， the susceptibility to chloramphenicol， ciprofloxacin， clindamycin， erythromycin， neomycin， tetracycline， trimethoprim， and vancomycin varied among the isolates. PCR analysis showed that several Bifidobacterium isolates harbored tet（W）. However， filter-mating experiments indicated no transfer of antibiotic-resistance genes. Conclusion： Bifidobacteria are not involved in further emergence of antibiotic resistant bacteria and that they are safe enough in this issue.

Abstract:In order to discriminate varieties and completed years of Chinese rice wine， H2SO4-（NH4）4Ce（SO4）4-CH2（COOH）2-KBrO chemical oscillation system was used to get the electrochemical fingerprint of Chinese rice wine by recording the electrochemical potential of oscillation system over time. The determining conditions were investigate in terms of temperature， stirring rate， hydrogen ion concentration， （NH4）4Ce（SO4）4 concentration， CH2（COOH）2 concentration， KBrO3 and Chinese rice wine amount etc. The optimum determining conditions were established with total volume of 100 mL， temperature of 39 ℃， stirring rate of 650 r/min， hydrogen ion concentration of 1.800 mol/L，（NH4）4Ce（SO4）4 concentration of 0.006000 mol/L， CH2（COOH）2 concentration of 0.08000 mol/L， KBrO3 of 1.116 g， Chinese rice wine of 1.40 mL. The results indicated that the electrochemical fingerprints of Chinese rice wine from different varieties and different completed years show significantly different characteristics， and can be used to identify the varieties and completed years of Chinese rice wine. The system similarity of the fingerprints of the same variety of Chinese rice wine was bigger than 97.59%， and the system similarity of the fingerprints of the different varieties of Chinese rice wine was less than or equal to 97.59%.

Abstract:The origin and season are important basis for judging the quality of abalone. Inductively coupled plasma mass spectrometry（ICP-MS） was used to determine the content of 16 inorganic elements in the samples from different habitats and seasons. The inorganic element database of Haliotis discus hannai was established and combined with cluster analysis for 18 wrinkles. The abalone samples were divided into regions to explore the feasibility of traceability of inorganic elements to traceability of the origin of Haliotis discus hannai. The results showed that the abdomen of the Haliotis discus hannai disk was rich in trace elements required by the human body， and the content and type of inorganic elements were affected by the season and the growth environment. The content of elements in summer and autumn was generally higher than that in winter and spring， and the content of Fe in autumn was ten. Times or even a hundred times higher than the other three seasons. The results of cluster analysis showed that the classification was significantly correlated with the origin and sea area distribution of the Haliotis discus hannai samples， but the effect of identifying the origin was related to the season.

Abstract:In view of the problems of complexity， low integration and multi-quality factors of egg sorting， an integrated inspecting and grading system of egg qualities was designed， which realized the automated inspecting and classification of the crack， size， freshness and quality level of eggs by using the machine vision algorithm. The designed system adopts pipelined structure which mainly consisted of an image acquisition unit， classification unit， transmission unit， image processing unit and micro-control unit. The image acquisition unit， classification unit， transmission unit were controlled orderly by the image processing unit and microprocessor unit， which were connected by the gigabit net port or the I/O joggle. Aiming at realizing the tiny egg cracks detection， the automatic threshold selection was presented based on the gradient magnitude histogram and maximum variance between clusters. Then， the cracked eggs were detected and identified， and eliminated in the classification unit I. In order to estimate the egg size， the maximum transverse diameter， maximum longitudinal diameter and the egg row index are measured by the minimum enclosed rectangle method. The eggs were sorted into two class of large and small in classification unit II. Through transforming the egg perspective images from RGB to HSI， the relationship between Haff value and the color components is analyzed. A back-propagation neural network is established to classify the freshness. Experimental results show that the accuracy of crack identification is 98.18%， the precision rate of special grade （AA） is 96.67%， the precision rate of grade A （A） is 98.31%， the precision rate of special grade B（B） is 96.67%， and the precision rate of egg quality recognition for different freshness grades is 97.48% generally. The designed system can be applied to online inspection of large-scale poultry and egg farms with high accuracy， simple structure and fast execution speed， as well as automatic inspecting and grading of other agricultural products.

Abstract:To isolate and purify the iridoids with antioxidant activity from ethanol extract of the Cornus officinalis， macroporous resin， normal phase silica gel， low pressure normal phase silican gel and cyanopropyl silica， Sephadex LH-20 and preparative HPLC column chromatography were used. The structures of the compounds were identified on the basis of spectral methods including NMR， MS and comparison with literature. The all compounds were evaluated the antioxidant activity using FRAP method and four iridoids with antioxidant activity were identified as loganin （1）， ketologanin （2）， 1-β-O-methyl loganin aglucone （3） and 1-deoxyloganin aglycone （4）. Compounds 3 and 4 were new natural products and reported in this species for the first time.

Abstract:In order to detect the dynamic changes of microorganisms during the fermentation of fermented sausages quickly and accurately. In this experiment， natural fermentation was used as a control group. Lactobacillus plantarum F16 was used as a fermenting agent to make fermented sausages， and the standard strain of Lactobacillus plantarum CICC：6238 was used to prepare standard substance. Quantitative analysis of lactic acid bacteria during fermentation of fermented sausages was performed by real-time fluorescence quantitative PCR and compared with traditional methods. The results showed that the correlation coefficient of the standard curve R2≧0.99， amplification efficiency was 90%-100%， which meet the requirements of RT-PCR. The quantitative results of lactic acid bacteria were the same as the plate counting which was incresed firstly and then decreased. The results of RT-PCR overestimated the plate count about 1lg（CFU/g）， probably because of the presence of dead cells. The linear equation between the plate counting and the RT-PCR values was obtained which was y = 0.8116x + 0.4254. A batch of sausage was taken to verify the experiment. The agreement reached more than 94% that the number of live bacteria according to the equation and the plate counts. Therefore， the linear equation could be used to predict the number of living bacteria of lactic acid bacteria， the method of RT-PCR provides a rapid and effective way to monitor the dynamic changes of lactic acid bacteria in the fermentation process of of fermented sausages.

Abstract:To determine the taxonomic classification of reference strain CMCC（B） 40001， which cited in GB 4789.28-2013 National food safety standard Food microbiological examination： Quality requirements of medium and reagents， polyphasic identification approaches including morphological features， 16s rRNA sequence， MALDI-TOF MS， VITEK 2 COMPACT automatic microbial analysis system and API were used. Results indicated that CMCC（B） 40001 was identified as Bordetella bronchiseptica and inconsistent with the scientific name- Alcaligenes faecalis in GB 4789.28-2013.

Abstract:The Pickering emulsions are stabilized by solid particles. Compared with traditional emulsions， they showed the advantages of better structural stability， biocompatibility， resistance to external pressure and lower toxicity to human environment， they manifested the ability to protect encapsulated bioactive substances and control their release. In recent years， functional Pickering emulsions are emerging in a variety of active materials， which are widely used in food， medicine and chemical industry. Based on the research of Pickering emulsion in recent years， the types of solid particles and the application progress of functional Pickering emulsion are summarized in the paper.

Abstract:Ethyl acetate is an important active aroma ester 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 ethyl acetate in Baijiu mainly came from biosynthesis pathway. Meanwhile， aroma-producing yeasts are the main strains that produce ethyl acetate. Especially， the research progress of alcohol acetyltransferase， which is one of esterification enzyme， in the synthesis of ethyl acetate in yeast was discussed. Meanwhile， the research on the synthesis of ethyl acetate by alcohol acetyltransferase in aroma-producing yeasts was prospected.

Abstract:Bitter substances， widely distributed and structurally diverse compounds， are of genuine plant origin mostly， few from animals， while others are generated during the processing， aging， or spoilage of food. The bitter substances in plants mainly include polyphenols， alkaloids， saponins， inorganic salts， amino acids and polypeptides. Bitter substances are perceived by taste buds， and their stimulations are converted into taste signals through bitter taste receptors and transmitted to the brain center to create a bitter sensation. Bitterness is unacceptable for most people， but it plays a key role in taste reconciliation and physiological regulation. Which can be combined with other tastes to enrich the flavor of food. At low intensity， mixtures of bitter with sweet or sour compounds enhanced each other， while umami and salty taste inhibit bitterness； at medium and high intensity， bitterness was suppressed by sweet， sour， umami and salty taste. Bitter substances have health benefits， can be widely used as additives in the food industry. Such as polyphenol， an antioxidant and antimicrobial， can be used for food preservation. Peptides can be added to health food and nutrition supplement to enhance the absorption of nutrition.

Abstract:Proteins and polysaccharidesroteins are important components in foods. The properties of polysaccharide-protein complex gels have an important influence on food quality. Therefore， the nutritional quality of polysaccharides and protein composite gels has received extensive attention. This article reviews the construction techniques， rheological properties of the protein-polysaccharide complex gel system， and the microstructure changes and applications during the formation of composite gels. The current problems are presented and prospected. The aim is to provide basis for precise development and quality control of foods rich in polysaccharides.

Abstract:Apple polyphenols are the secondary metabolites of apple fruit， including phenolic acids， flavanols， flavonols， dihydrochalcone and anthocyanins. The composition and content of apple polyphenols is closely related to the apple species， of which a series of genes and enzymes related to the expression， synthesis and transformation are the determinative factors. Meanwhile， the accumulation of apple polyphenols is also affected by cultivation method， environmental conditions， fruit maturity and storage conditions etc. The diversity of apple polyphenol resources will affect and determine its functionality in food processing and bioactivity in food consumption. The strong antioxidant potential of phenol hydroxyl， reductive ketone and condensed phenol structure of apple polyphenol is the fundamental functional basis for its utilization in food processing， preservation， as well as the modulation of physiological activity. Based on antioxidant capacity of apple polyphenols， several researches involves lowering blood glucose， lowering blood lipids， repairing tissue and organ damage， preventing and inhibiting proliferation， migration and apoptosis of cancer cells， improving body immunity and physical ability， and promoting hair growth and skin activity have been conducted. This review attempted to summarize the studies on the polyphenol content， composition， biosynthesis， distribution， functionality in food processing and physiological and biochemical function of apple polyphenol in recent years， so as to provide ideas and references for fully recognition and exploring the functional application of apple polyphenol resources.

Abstract:In recent years， lactic acid bacteria has become a research hotspot for its promotion of human health function. At present， the adhesive ability of lactic acid bacteria is widely used as the primary indicator to evaluate the probiotic nature of lactic acid bacteria. The adhesion ability of lactic acid bacteria to intestinal epithelial cells or extracellular matrix components can cause beneficial biological effects in the body. The adhesion mechanism of lactic acid bacteria is preliminarily elucidated from the interaction between the adhesin of lactic acid bacteria and host receptor. At the same time， the external and internal factors affecting the adhesion capacity of lactic acid bacteria are also reviewed. And the progress of the research methods for evaluating the adhesion characteristics of lactic acid bacteria at home and abroad is summarized in order to lay a theoretical foundation for the research and application of the adhesive characteristics of lactic acid bacteria.

Abstract:The application of food self-heating technology can fully preheat the pre-made food to a suitable temperature in a short time to meet the consumer demand for delicious， safe， nutritious and convenient food in special application scenarios. Self-heating agent is an important heat source in food self-heating technology. However， there are few related researches on the heating law of self-heating agent and improving the self-heating efficiency of food. This paper analyzes the heating principle of various food self-heating agents， compares the thermal efficiency of various self-heating technologies， discusses the research progress of simulation and optimization of food reheating process， and summarizes the problems existing in self-heating foods and future research. The key direction is to provide technical support for the improvement of food self-heating technology and industrial application.