Abstract:Streptococcus thermophilus is one of the most important starters in the dairy industry， with good fermentation characteristics. DNA methylation is a form of chemical modification of DNA that can affect gene expression without altering the DNA sequence. In this paper， two strains of Streptococcus thermophilus with large differences in acid-producing phenotype were selected as the research objects， and the relationship between m6A methylation and genetic phenotype was explored through methylome. The PacBio SMRT sequencing platform was used to sequence the genomes of Streptococcus thermophilus IMAU80278 and Streptococcus thermophilus IMAU20416 and measure the m6A methylation to compare the functional genes and m6A methylation differences between the two strains of Streptococcus thermophilus. The results showed that the genomes of Streptococcus thermophilus IMAU80278 and Streptococcus thermophilus IMAU20416 were similar， and the functional genes were mainly carbohydrate metabolism and amino acid metabolism. Streptococcus thermophilus IMAU80278 and Streptococcus thermophilus IMAU20416 showed significant differences in restriction modification systems， m6A methylation sites and m6A motifs， especially in the m6A methylation of genes related to carbohydrate metabolism and amino acid metabolism. It is speculated that the difference in m6A methylation may lead to the different acid-producing phenotypes between Streptococcus thermophilus IMAU80278 and Streptococcus thermophilus IMAU20416. In addition， this study explored the effect of Streptococcus thermophilus DNA methylation on fermentation characteristics from the perspective of epigenetics， and laid a theoretical foundation for the selection and utilization of excellent starter.

Abstract:The stability of Glycyrrhiza polysaccharide / casein complex was analyzed by Zeta potential and turbidity， and the structural properties and interaction mechanism of GP/CS complex were investigated by fluorescence spectrum， infrared spectrum and circular dichroism spectrum， ect. The emulsifying stability of compound emulsion was also discussed. The results showed that GP/CS could form a stable complex. When pH=7， the Zeta potential values of GP/CS complexes were between CS and GP solution， with the average particle size increasing and fluorescence intensity decreasing， and the ultraviolet absorption intensity decreasing with blue shift， the intensity and peak width of the absorption peak of the infrared spectrum were changed， and the secondary structure of casein were changed. The electrostatic interaction， hydrogen bonding and hydrophobicity were involved in the formation of the composites. In addition， GP/CS complex could improve the stability of the emulsion. This study provides reference for the application of protein-polysaccharide complex in food field.

Abstract:Ellagic acid (EA) is a natural polyphenol with antioxidant， anti-cancer， anti-mutation， anti-inflammatory and other physiological activities. The interaction between ellagic acid and protein will directly affect its transport and metabolism in the human body. In this paper， a variety of spectroscopic methods and molecular docking simulation methods were used to study the reaction mechanism of the interaction between EA and bovine serum albumin (BSA). The results of UV spectroscopy and fluorescence spectroscopy showed that EA quenched the endogenous fluorescence of BSA in a static manner， EA and BSA combined to form a stable complex through BSA， resulting in the decrease of α-helix structure and the increase of β-sheet， β-turn and random coil structure in BSA. There may be hydrophobic interactions between them. Molecular docking simulation further verifies the results of the above spectral analysis， which shows that in addition to the van der Waals force and hydrogen bond， the dominant force for the binding of EA and BSA also has a certain hydrophobic force. The optimal binding site of EA on BSA is located in the hydrophobic cavity between subdomain IIA and subdomain IIIA， which is closer to site I. There are hydrophobic interactions between EA and residues such as His145， Pro110， and Arg458， and there are hydrogen bonds between residues of EA and Arg144. This study clarified the molecular mechanism of the interaction between EA and BSA， and provided useful information for the study of EA transport and metabolism in vivo.

Abstract:The effects of gallic chatechin gallate (EGCG) on the digestion properties and protein oxidation of sea bass fillets by microwave heaing was studied. By simulating the gastrointestinal digestion process， the digestibility， particle size， carbonyl， free sulfhydryl， free amino acid contens changes and the morphology of the digestion products were determined. The results showed that digestion of sea bass fillets was basically completed at 40 min， and the protein digestibility was 75.23%. The sea bass slices by EGCG-treating were digested for a longer time， but there was no significant effect on the digestibility. After 120 min of intestinal digestion， the protein digestibility reached 72.13%~76.16%. The carbonyl content in gastric digestion was significantly higher than that in intestinal digestion. After 40 min of digestion in the intestine， the carbonyl content was decreased by 20.76%-30.58%. EGCG delayed the reduction of free sulfhydryl content， and reduced the oxidation level of protein. The particle size in the digestion product system of the EGCG treatment group decreased in concentration-dependent type and reduced the micromorphological aggregation， while reducing the content of free amino acids.

Abstract:Pingyin rose was approved as a new resource food in 2010， which is a unique rose resource food in Shandong province of China. Anthocyanins were extracted and preliminarily identified from Pingyin rose. RAW264.7 macrophages were induced by lipopolysaccharide (LPS)， advanced glycation end products (AGEs) and 4-hydroxynonenal (4-HNE) to construct inflammatory model. The effects of anthocyanins on the production of reactive oxygen species (ROS) and nitric oxide(NO) and the expression of some inflammatory factors in RAW264.7 cells were studied. Results showed that rose anthocyanins mainly contained two aglycones， namely cyanidin and peonidin. A total of six anthocyanins were identified， including three cyanidin-dihexoses， two peonidin dihexoses and peonidin-rutinose-hexose. Anthocyanins could significantly inhibit the production of ROS and NO and the expression of IL-1β， IL-6， TNF-α， iNOS in RAW264.7 cells， showing a good inhibitory effect on inflammation.

Abstract:Five Bacillus strains were isolated from the traditional homemade shrimp paste， and were identified as Bacillus amyloliquefaciens Y11， Bacillus velezensis Y12， Bacillus subtilis Y13， Bacillus safensis Y32， and Bacillus cereus BI6Y. All five strains could grow normally at 10% NaCl concentration， had different protease and lipase and antibacterial substances production capacities. Among them， Bacillus cereus BI6Y has β-hemolysis and is insensitive to chloramphenicol， vancomycin and norfloxacin， hence is not suitable for a probiotic. The other four Bacillus strains are γ-hemolytic， insensitive to chloramphenicol， with a self-aggregation rate between 25% and 35%， and tolerant to acid and bile salts； they were found to secrete surfactin and could survive after treatment with artificial gastrointestinal fluid， the strain that had the highest survival rate in artificial gastric juice (pH 2.0) was found to be B. subtilis Y13 (95.3%)， and in artificial intestinal juice it was B. safensis Y32(85.1%). The bacterial cell， cell-free supernatant， and cellular contents had different antioxidant activities， and the cell-free supernatant could scavenge 1，1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl radicals simultaneously， the scavenging rate is between 40% and 60%. The results of the study showed that in addition to B. cereus BI6Y， B. amyloliquefaciens Y11， B. velezensis Y12， B. subtilis Y13， B. safensis Y32 have certain safety and probiotic properties， hence could be used as potential probiotics， which would provide a theoretical basis for the development of Bacillus. spp-based probiotic products.

Abstract:In this study， lactic acid bacteria (LAB) with producing γ-aminobutyric acid (GABA) were screened from traditional pickled vegetables in Northeast China using thin-layer chromatography(TLC) and the Berthelot colorimetric method. LAB were identified by the physiological and biochemical test and 16S rRNA sequencing analysis. And then their biological properties， including acid tolerance， bile salt tolerance， antioxidant， antibacterial activity， antioxidant activity and acid production rate， were analyzed using principal component analysis (PCA). These results showed that five strains LAB with typical GABA-producing were obtained from forty strains LAB from traditional pickled vegetables， including one strain Weissella kandleri HJL2 and four strains Lactobacillus plantarum PJ-7， HJG1-3， L-9， and L-11. Among them， L. plantarum PJ-7 isolated from fermented radish had better ability to synthesize GABA， and the yield reached 0.48 mg/mL. There were significant differences in acid tolerance， bile salt tolerance， antioxidant and other biological characteristics of the five strains LAB. Based on PCA， L. plantarum PJ-7 ranked the first in the comprehensive score of biological characteristics. Therefore， L. plantarum PJ-7 has excellent GABA synthesis ability and good biological characteristics， which would provide a theoretical basis for the development of GABA- rich pickled vegetables.

Abstract:Objective: To investigate the effects of preservative (dehydroacetic acid and ε-polylysine hydrochloride) and incubation temperature on the growth and toxin production of Burkholderia gladiolus on wet rice flour medium. Methods: A Burkholderia acorus(P. coenovenae) strain isolated from a food poisoning event was used as the research object. The strains were inoculated into wet rice flour medium supplemented with dehydroacetic acid (1.0 g/kg)， ε-polylysine hydrochloride(0.25 g/kg) and no preservative， and cultured at 10， 26 and 36 ℃ to study the growth and virulence of the strains in wet rice flour. The modified Gompertz model was used to construct the primary growth model. Results: At 10 ℃， the strain grew slowly and did not produce bongkrekic acid. At 26 ℃， the strain produced toxin more than 500 μg/kg in the control group and all experimental groups when cultured to 96 h. The strain produced bongkrekic acid the earliest in the samples with dehydroacetic acid， and its maximum concentration (1 484 μg/kg) was slightly lower than that in the control group (2 561 μg/kg) and ε-polylysine hydrochloride group (2 762 μg/kg). The most rapid growth was observed at 36 ℃， but the production of toxin was lower than 350 μg/kg. Conclusion: Storage of wet rice flour at 10 ℃ can effectively reduce the risk of producing rice krekic acid. Both dehydroacetic acid and ε-polylysine hydrochloride failed to prevent the growth and toxin production of Burkholderia gladiolus. It is necessary to further explore effective preservants to develop multi-means control measures.

Abstract:In order to investigate the effects of NaCl on the physicochemical and gel properties of myofibrillar protein (PeMP) from the body wall of Phascolosoma esculenta Chen et. Yeh， the determination and observation results of solubility of total PeMP， solubility of different types of proteins from PeMP， ultraviolet absorption spectrum， endogenous fluorescence spectrum， Zeta potential， Fourier transform infrared spectrum (FTIR)， sulfhydryl group contents， surface hydrophobicity， denaturation temperature and gel structure were analyzed. The results showed that the solubility of PeMP increased， the contents of paramyosin and myosin increased significantly， with the increase of NaCl concentration. The maximum absorption wavelength (λmax) of the ultraviolet absorption spectrum of PeMP， of the corresponding second derivative spectrum of ultraviolet absorption spectrum of PeMP and of the endogenous fluorescence spectrum of PeMP was redshifted， respectively. The Zeta potential of PeMP increased. FTIR analysis showed that the secondary structure of PeMP changed， the β-sheet increased， while the α-helix decreased gradually. The contents of total and non-protein sulfhydryl groups decreased in PeMP， but the contents of typing sulfhydryl group increased， and the surface hydrophobicity of PeMP increased. The denaturation temperature of PeMP decreased. Protein molecules of PeMP gel were more tightly packed. These results will lay a foundation for the improvement of the gel of body wall from P. esculenta and the preparation of high-quality 'earth bamboo shoot jelly' products.

Abstract:Hovenia acerba Lindl is a traditional food or medicine homologous to food and medicine， which has the effects of lowering blood sugar and pressure， relieving alcohol and protecting liver. However， the mixed use of Hovenia acerba Lind pulp and seed brings a lot of inconvenience to its application and inspection. In order to determine the active site of Hovenia acerba Lind， the effects of water and 95% ethanol extract from pulp and seed on α-glucosidase activity in vitro and Streptozocin(STZ) -induced hypoglycemic activity and its substance basis in type II diabetes model mice were studied. The results showed that seed ethanol extract(SEE) was the main active substance for inhibiting α -glucoside， and the IC50 of SEE was 0.97 mg/mL， which was a competitive inhibitor. The water extract of pulp (PWE) was the main active substance， and the IC50 of PWE was 2.28 mg/mL， which was a mixed inhibitor. The inhibition activity of α-glucosidase in SEE and seed water extract(SWE) was higher than PWE and pulp ethanol extract (PEE). Animal experiments showed that the four extracts could reduce the blood glucose and improve the glucose tolerance and body weight of the mice to varying degrees， but the SEE had the most significant effect (P < 0.01). Overall， the order of hypoglycemic activity was SEE>SWE>PWE>PEE， seed is the main active part of Hovenia acerba Lind in lowering blood glucose， and its hypoglycemic effect is stronger than that of pulp. Five compounds were isolated and purified from the SEE by silica gel， C18 medium pressure liquid chromatography and Sephadex LH-20 column chromatography. Compounds 1-5 were identified as quercetin， dihydroquercetin， myricetin， dihydromyricetin， and quercetin-3-O-β-D-glucopyranoside by ESI-MS， 1HNMR， 13CNMR， HSQC and HMBC. This study provided a theoretical basis for solving the problem of Hovenia acerba Lind pulp and seed mixing， and provided a new way for further development and utilization the resources.

Abstract:Objective: To investigate the effect of wheat peptides on intestinal damage from non-steroidal anti-inflammatory drugs(NSAIDs). Methods: The 4-week-old male KM mice were randomly divided into 6 groups according to body weight， namely blank group (saline gavage)， diclofenac sodium group (diclofenac sodium gavage)， glutamine group (diclofenac sodium + glutamine)， wheat peptide low， medium and high dose groups (diclofenac sodium + different doses of wheat peptide)， 10 mice in each group， and treated continuously for 21 days. Mice were fasted for 12 h after the final gavage and weighed. Mice were subjected to blood sampling for oxidative stress levels and adrenaline E2 (PGE2) assays. Mouse intestine tissue was collected for histopathological testing and western blot was used to detect the expression of intestinal tissue tight junction proteins. Results: Compared with the diclofenac sodium group， mice in the wheat peptides and glutamine groups had higher body weights， lower levels of oxidative stress and restored PGE2 expression to normal levels. The mucosal barrier damage in mouse intestinal tissues was improved and the expression of tight junction protein was increased. Conclusion: Wheat peptides have protective effects against diclofenac sodium-induced intestinal disorders. It is promising to provide an effective method to protect against NSAIDs intestinal barrier function impairment.

Abstract:Flaxseed oil is favored by consumers because of its high nutritional value. However， the effect of thermal processing on the quality of flaxseed oil remains to be clarified. The effects of dry-air roasting on the physicochemical properties (acid value， peroxide value， color)， chemical composition (conjugated diene， conjugated triene， carotenoids， tocopherol， total phenolics， Maillard reaction products， fatty acid composition)， oxidation stability index， DPPH， and ABTS of flaxseed oil were investigated. The results showed that with the increase of roasting degree， the color of flaxseed oil became darker， the acid value increased， the peroxide value and conjugated diene first increased and decreased， while carotenoids， total phenols， Maillard reaction products， conjugated trienes， oxidation stability index， DPPH， and ABTS increased during roasting. The content of α-linolenic acid decreased slightly in the roasting process. Moderate roasting significantly improved the quality of flaxseed oils. The results of this study would provide support for flaxseed and flaxseed oil processing.

Abstract:Grains are rich in nutrition and have many functions. It can improve the nutritional value of rice when mixed with rice. However， the consumption rate of grains is low because of their poor taste and difficulty in cooking. In this study， black rice， coix seed， sorghum and oat were treated by pre-gelatinization technology， and the eating quality of the multigrain rice was evaluated by chroma meter， texture analyzer， sensory evaluation and preference score. The results showed that the black rice could be cooked with rice after pre-gelatinization for 5 min， while coix seed， sorghum and oat could be cooked with rice after pre-gelatinization for 10 min. The pre-gelatinization treatment had a great effect on the color of black rice and sorghum， and the a and b value of black rice decreased by 33.02% and 11.76%， and the a and b value of sorghum decreased by 41.38% and 14.40%. After pre-gelatinization for 25 min， the hardness of black rice， coix seed， sorghum and oat decreased， while the springiness and cohesiveness of black rice， coix seed， sorghum and oat increased. The palatability of black rice and sorghum increased by 35.39% and 131.04% after 20 min of pre-gelatinization， and the palatability of coix seed and oat increased by 229.05% and 82.17% after 25 min of pre-gelatinization. When the proportions of black rice， coix seed， sorghum and oat with rice were 30%， 20%， 20% and 20%， the preference score of multigrain rice was the highest， which were 15， 14， 14 and 15 points respectively. Hot air drying and vacuum packing could effectively delay the increase of fatty acid value and peroxide value of multigrain rice during storage. The quality of multigrain rice met the requirements after 40 d storage at room temperature.

Abstract:Millet protein was used as raw material to prepare food-derived peptides with antioxidant activity and angiotensin transferase(ACE) inhibitory activity. Alkaline protease， neutral protease and flavor protease were used to hydrolyze millet protein. Three components with molecular weight < 3， 3-10 ku and > 10 ku were obtained from the hydrolysate obtained by alkaline protease for 4 h， and their antioxidant and ACE inhibitory activities were determined. The results showed that the polypeptides with molecular weight < 3 ku obtained from the hydrolysate obtained by alkaline protease for 4 h after ultrafiltration had the highest antioxidant activity and ACE inhibitory activity， with DPPH scavenging capacity of 38.44%， ABTS free radical scavenging capacity of 81.62%， hydroxyl radical scavenging capacity of 68.49%. The inhibitory activity of ACE was 87.53%. The polypeptides obtained by this method have low molecular weight， high content of functional amino acids， and have good antioxidant and ACE inhibitory activities， which provide a basic for the development of antioxidant peptides and ACE inhibitory peptides， and provide a theoretical basis for the future industrial development.

Abstract:This study aimed to extract pectin from local Majiayou pomelo (Citrus grandis(L.) Osbeck) peel in Jiangxi province with distilled water， hydrochloric acid and citric acid， respectively， and analyze the physicochemical components of pectin and its adsorption properties on Pb(Ⅱ)， and explicit the effect of adsorption parameters (initial pH value， initial ion concentration， adsorption time) on Pb(Ⅱ) and its adsorption mechanism by adsorption isotherms and adsorption kinetics. The results showed that the yield of pectin by citric acid extraction (CEP) was highest (28.62%)， followed by hydrochloric acid extraction (HEP) and distilled water extraction (WEP). In addition， the esterification degree (58.20%) and molecular weight (598.40 ku) of CEP were significantly lower than those of WEP and HEP (P<0.05)， indicating that CEP had more carboxyl and higher solubility. The three pectins showed optimal adsorption of Pb(Ⅱ) at initial pH 5.0， and reached equilibrium after 120 min adsorption. In addition， the adsorption capacity of CEP on Pb(Ⅱ) was significantly higher than that by WEP and HEP. The adsorption isotherms of the three pectins were in accordance with Langmuir monolayer adsorption model， and the adsorption kinetics of the three pectins was consistent with pseudo first-order kinetics model. The adsorptions of three pectins on Pb(Ⅱ) were the result of physical and chemical adsorption. Conclusion: The physicochemical properties of pectin and its adsorption capacity on Pb(Ⅱ) were closely related to the extraction method， and CEP has a high adsorption capacity on Pb(Ⅱ)， which could be used as a low-cost， efficient， natural and environmental friendly adsorbent for removal of Pb(Ⅱ).

Abstract:High blood pressure is a major risk factor for cardiovascular disease， and frequent use of blood pressure medications can have side effects. Therefore， safe and efficient food-borne antihypertensive peptides have become the focus of attention. In this study， a quantitative structure-activity relationship(QSAR) model of angiotensin-converting enzyme (ACE) inhibitory peptide was established to determine the relationship between the structure and activity of ACE inhibitory peptide. The model results were combined with computer virtual enzyme digestion to determine proteolytic sites accurately. Suitable proteases were selected to hydrolyze hemp seed protein to prepare ACE inhibitory peptide， and the inhibitory effect of the final hydrolysate was determined. The results showed that the SVM-AAindex model based on dipeptide had the best predictive performance(R2 0.81， RMSE 0.53)， and had a strong ACE inhibition effect when the C-terminal amino acids of dipeptide were hydrophobic and aromatic amino acids. The analysis of protein components showed that hemp seed protein contains 34.60% hydrophobic amino acids and aromatic amino acids， which is a good source for preparing ACE inhibitory peptides. The alkaline and subtilisin， which produced more short peptides and bioactive peptides by virtual enzyme digestion， were selected for directed hydrolysis of hemp seed protein. The ACE inhibition values of the final hydrolysates were 1.89 and 2.30 mg/mL， respectively. In this study， an efficient and accurate method for preparing ACE inhibitory peptide from hemp seed protein was established， which has a good application prospect in antihypertensive drugs.

Abstract:In order to reduce the content of biogenic amines in low-salt shrimp paste and develop multiple varieties of new flavor low-salt shrimp paste， low-salt shrimp paste added with ginger， cinnamon， clove and perilla was prepared in this study. Determination of biogenic amines by high performance liquid chromatography； based on sensory quantitative description analysis and gas chromatography-ion transfer spectroscopy， the flavor quality and volatile flavor compounds were evaluated. Principal component analysis and partial least squares discriminant analysis were used to screen the key differential compounds in shrimp paste with different spices， and the thermal graph clustering analysis was carried out. The results of test date showed that ginger， cinnamon and clove had inhibitory effects on biogenic amine formation. Compared with the control group， the total biogenic amine content decreased by 67.42%， 42.47% and 3.72%， respectively. The contents of tryptamine and histamine in perilla shrimp paste were 121.7% and 124.1% higher than those in the control shrimp paste. A total of 61 volatile compounds were identified by GC-IMS. Sensory quantitative description analysis， difference spectrum and nearest Euclidean distance map showed that the addition of perilla and cinnamon had little effect on the original flavor of shrimp paste. A total of 19 differential volatile compounds were screened out by PLS-DA model； the thermal diagram cluster analysis showed that the characteristic volatile substances of clove shrimp paste and ginger shrimp paste had high content of low-level saturated aldehydes， which would bring stimulating odor to shrimp paste. The addition of cinnamon and perilla gave shrimp paste more fresh aroma and baking aroma. In summary， cinnamon low-salt shrimp paste is a new flavor low-salt shrimp paste with improved safety.

Abstract:Objective: To optimize the purification process of AB-8 macroporous resin for peanut red procyanidins and to characterize and identify the components of the purified product， and to evaluate its inhibitory effect on cytotoxicity in celiac disease model. Methods: AB-8 macroporous resin was selected， and the purification conditions were optimized by static and dynamic adsorption-desorption indexes. The purified material was analyzed and identified by Ultraviolet/visible spectroscopy， Fourier transform infrared spectroscopy and High performance liquid chromatography-tandem mass spectrometry (UPLC-QTOF-MS/MS). The inhibitory effect of purified material on cytotoxicity was evaluated based on celiac disease cell model. Results: Purification conditions: The adsorption time was 180 min. The desorption solution was 120 mL 40% ethanol solution. The desorption time was 40 min. The desorption flow rate was 1.0 mg/mL. Ultraviolet/visible spectrum analysis showed that the purified substance belonged to proanthocyanidins. Fourier infrared analysis showed that protocyanin was the main structural unit of the purified product， which was consistent with the characteristic absorption peak trend of the standard product. UPLC-QTOF-MS/MS analysis showed that type A procyanidins were the main component of Pspc purified products. The results of cell test showed that the purified substance could significantly inhibit the toxicity of celiac disease model to some extent. This study can provide some theoretical reference for comprehensive development of peanut red resources.

Abstract:Millet bran is rich in nutrients and bioactive components. Polyphenols play an important role as one of the active components， but their properties are not very stable and are prone to oxidative degradation under certain conditions. In this paper， we extracted polyphenols from millet bran by ultrasonic combined with DESs and prepared microcapsules by embedding them to study their physicochemical properties. The results showed that the total polyphenol content of millet bran was 10.58 mg/g under the conditions of ultrasonic-assisted extraction for 30 min at 45 ℃ with a material-liquid ratio of 1∶36 g/mL. After the microcapsules were prepared， the structure of millet bran polyphenol microcapsules was analyzed by scanning electron microscopy， and it was found that the outer surface of the microcapsules was smooth and the particles were of uniform size. The infrared spectrum showed that the yeast cells had a good effect on the encapsulation of millet bran polyphenols； in the simulated gastric juice， the release of millet bran polyphenol microcapsules was faster than in the simulated intestinal juice， and the core material was released up to 96% within 2 h， and the core material was basically released completely after 5 h. Microencapsulation increased the stability performance of millet bran polyphenols， and provided the theoretical basis for the deep development and utilization of millet bran.

Abstract:Gas chromatography-ion mobility spectrometry(GC-IMS) was performed to investigate the changes of volatile organic compounds(VOCs) in fried green tea with different packaging during storage. The results showed that a total of 86 VOCs were detected by GC-IMS， of which 59 VOCs were identified， including 28 aldehydes， 7 ketones， 9 alcohols， 9 esters， 4 heterocyclic compounds， 1 acids and 1 sulfur. With the extension of storage time， the content of fried green tea VOCs decreased. More importantly， the VOCs of green tea were more stable in packaging of aluminum with deoxidizer than packaging of aluminum. And the content of (E， E)-2，4-heptadienal and heptanal with clean and refreshing， benzaldehyde and phenylacetaldehyde with chestnut， nonanal and 6-methyl-5-hepten-2-one with flowery， 2-heptanone with cheese flavor and etc were higher in packaging of aluminum with deoxidizer. These study supply a theoretical basis for the flavor quality control of fried green tea during storage. The two-dimensional spectrogram showed that VOCs of fried green tea with different packaging during storage could be well separated. The GC-IMS fingerprints of fried green tea with different packaging were preliminarily established， which provided a novel idea for the rapid evaluation of the fried green tea quality during storage.

Abstract:Norovirus(NoV) is one of the major pathogens causing acute gastroenteritis diseases worldwide and is highly susceptible to outbreak transmission， increasing medical and economic burden. Objective: To develop a novel detection method for NoV by recombinase aided amplification (RAA). Methods Based on the cDNA sequences corresponding to the GI and GII NoV detection targets specified in ISO TS 15216-2-2013 and GB 4789.42， the optimal RAA primers and probes were designed and screened， and their specificity for other common food-borne diarrhea viruses was determined； the shortest detection time， reaction procedure， and reaction system were determined by optimization， and the analysis of this detection system was performed. The shortest detection time， reaction procedure and reaction system were optimized， and the sensitivity of the assay system for the detection of NoV reference plasmids and real samples was analyzed， thus establishing a rapid visualization method for the detection of GI and GII NoV RAA. The optimized reaction procedure can shorten the detection time to about 10 min and reduce the reaction cost by two-thirds， and the sensitivity of the method can reach 10-2 ng/μL for the reference plasmid and 1 ng/μL for the real sample. The two NoV assays established are specific， sensitive， simple， rapid and visualized， and provide a good basis for future rapid NoV detection.

Abstract:Objective: To understand the status of the pesticide residues and their dietary exposure risk of litchi sold in city markets. Methods: 126 pesticide residues in 100 batches samples of the whole fruit and pulp of litchi collected from Shanghai， Hangzhou， Nanjing， Changsha and Jinan were detected and analyzed. The risk of chronic dietary exposure and acute dietary exposure of the residues were assessed and ranked. Results: The detection rate of pesticide residues in the whole fruit and pulp of litchi was 100% and 54%， the number of the pesticides detected was 38 and 12， and the exceeding rate is 43% and 0%， respectively； The risk range of pesticide chronic dietary exposure was 0.00~21.75%， with an average of 1.05%， and the risk range of acute dietary exposure was 0.03~37.00%， with an average of 2.99%. There were 5 kinds of high risk pesticides， including chlorpyrifos， cypermethrin， methomyl， pyrazolidoxifen and omethoate， and the medium and low risk pesticides were 8 and 25 respectively. Conclusion: The risk values of chronic dietary exposure and acute dietary exposure of pesticide residues in the whole fruit of litchi sold in five cities were lower than 100%， which was acceptable； The situation of pesticide residues in the whole fruit of litchi was not optimistic， the pesticide residues level in pulp is lower than that in the whole fruit， thus their dietary exposure risk is also lower； It was suggested that the registration of pesticides used in litchi and the formulation and revision of the maximum residue limits (MRLs) required.

Abstract:Bisphenols(BPs) are suspected posing potential endocrine disrupting properties. Occurrence of BPs has been reported in environmental matrices. BPs might migrate into foodstuffs through food packaging materials or contaminated water and soil. Information on the occurrence of bisphenols， other than BPA， in foodstuffs， however， is scarce. Dietary exposure is of paramount importance way for human health. In this study， eight BPs， including BPA， BPS， BPP， BPB， BPAP， BPAF， BPF and BPZ， were analyzed in market foodstuffs (N = 278) collected from Guangyuan， Sichuan， China， using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) foodstuffs were divided into ten categories of beverages， dairy products， eggs， cquatic foods， cereals， meats， fruits， vegetables， canned food and packaged drinking water. Bisphenols were found in the majority (76.3%) of the food samples， and the total concentrations of bisphenols (ΣBPs: sum of eight bisphenols) were in the range of below the limit of detection (LOD) to 59.08 μg/kg， with an overall mean value of 3.12 μg/kg. The higher overall mean concentration of ΣBPs was found in canned food， cereals， cquatic foods and vegetables. The predominant bisphenol analogues found in foodstuffs were BPA and BPS， which accounted for 77.9% and 14.4% of the total BPs concentrations， respectively. On the basis of measured concentrations and daily ingestion rates of foods， the daily dietary intakes of bisphenols (calculated from the mean concentration) were estimated to rang from 42.59 ng/kg bw/d to 96.54 ng/kg bw/d for different age and gender groups. BPA contributed to the majority of the total intakes of the BPs， followed by BPs. The daily dietary intakes of BPs showed a decrease with the growth of the age. It should be noted that dietary intakes of people aged 2-19 year old (critical time of development， 87.96 ng/kg bw/d) were obviously higher than that of aged above 19(48.05 ng/kg bw/d). Based on the t-TDI set by EFSA (4 μg/kg bw/d for BPA)， the BPs through dietary intake pose low risks on the general population even summarization exposure levels of different BPs. However， the production and application of BPA analogues are increasing worldwide， and the health risks caused by BPA analogues should be continuously concerned.

Abstract:It is challenging to identify the features of subsurface fresh bruises of fruits and vegetables by traditional uniform imaging techniques due to the mild symptoms. Owing to the capability of depth-varying and signal-enhanced characterization， spatial-frequency domain imaging was used to detect the fresh bruising (within 30 minutes) of 10 kinds of fruits and vegetables (carrot， Fuji apple， cucumber， golden delicious apple， fruit cucumber， delicious apple， mango， yellow peach， rose plum， and honey peach). Through the procedures of image acquisition， image demodulation， whiteboard correction and inverse estimation， optical properties of the fruits and vegetables were obtained. The results indicated that there were great differences of optical properties between non-bruised and bruised samples， with decreased values of reduced scattering coefficients for the bruised ones， which visually realized the non-destructive detection of early bruising. The novel method proposed in this paper is promising for non-destructive detection of early bruising of fruits and vegetables.

Abstract:To identify Dendrobium species and to analyze the habitats of Dendrobium officinale， the suitable candidate DNA barcoding genes of Dendrobium were evaluated. In this study， the internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA and chloroplast psbA-trnH gene were amplified and sequenced from sixty-six samples of D.chrysotoxum， D.nobile， D.primulinum and D.officinale. The D.officinale samples were collected from Hangzhou， Huoshan， Yunnan and Wenzhou. The intra-specific and inter-specific divergence of Dendrobium was calculated， and the identification efficiency was assessed using Barcoding Gap， NJ tree by K2P distance. The results showed the intra-specific divergence of ITS2 (0-0.005) were obviously lower than the inter-specific divergence (0.070-0.228)， and four species of Dendrobium were also accurately distinguished in NJ tree. Whereas， there is no Barcoding Gap on psbA-trnH， and it cannot distinguish D.nobile and D.primulinum in the NJ tree， and it can be used as a supplementary sequence in the identification of Dendrobium. ITS2 and psbA-trnH of D.officinale from four habitats have multiple mutation sites， which have the potential to identify the habitats of D.officinale.

Abstract:Vibrio parahaemolyticus is a foodborne pathogen of high risk in marine foods. In this study， an antimicrobial peptide designated FAH34(amino acid sequence: KTISFILK) was identified from distiller's grains Larimichthys crocea， and its thermal stability， antibacterial activity， and mechanism of action against V. parahaemolyticus explored. Peptide FAH34 had a minimum inhibitory concentration (MIC) of 7.80 μg/mL， while time-kill analysis showed that bacteria numbers decreased time-dependently from 5.06 lg(CFU/mL) to 0 lg(CFU/mL) within 3 h upon treatment with FAH34. Transmission electron microscopy examination revealed that FAH34 caused the destruction of bacteria membranes resulting in the leakage of bacterial contents. Besides， heat treatment (80 ℃ for 30 min or 121 ℃ for 15 min) of FAH34 did not significantly affect its antibacterial activity. Moreover， peptide FAH34 (with and without heat treatment) did not significantly affect the viability of LO₂ cells. Additionally， FAH34 could reduce bacteria (V. parahaemolyticus) counts to 0-0.40 lg (CFU/mL) in fish and marinade. These findings indicate that peptide FAH34 can be used as a biological preservative against V. parahaemolyticus in fermented foods or thermally processed foods.

Abstract:In this study， Gas chromatography-mass spectrometry (GC-MS) was used to analyze the changes of flavor substances during the fermentation of congee， and its physicochemical properties and sensory quality were analyzed. The results showed that the 0-48 h pH value rapidly decreased from 4.09 to 4.13 during the fermentation process， and the acidity showed a step rising trend. The acidity increased from 4°T to 31.2°T during 0-48 h fermentation. The total sugar content increased first and then decreased， and the total sugar content increased from 85 mg/L to 93 mg/L during 0-6 h fermentation. The total sugar content decreased from 83 mg/L to 52 mg/L during fermentation 12-48 h. With the extension of fermentation time， L value of congee showed a decreasing trend from 57.5 to 30.55 for 0-48 h， a value and b value increased from 0.55 to 0.35 for 0-48 h， and b value increased from 0.35 to 5.70. A total of 16 amino acids were detected from the congee samples. The content of total amino acids increased to twice of that of 0 h after fermentation for 48 h， and the content of glutamic acid and aspartic acid was the highest. The detection results of electronic nose technology showed that W5S (nitrogen oxide compounds)， W1S (methyl groups) and W1W (sulfide sensitive) sensors were more responsive to congee samples. In terms of taste， sour porridge has the strongest response signal of sour， sweet and salty taste. GC-MS analysis showed that 90 volatile compounds were detected from the sour porridge， among which ethyl acetate， eunesol， nonylaldehyde， ethyl enanthate and acetic acid were important aroma components. This study provides theoretical reference for further development of congee products.

Abstract:The brewing of quinoa wine using traditional solid-state fermentation method is of great significance to extend the quinoa industry chain. In this study， quinoa and sorghum were used as the main raw materials to brew quinoa wine and sorghum wine by solid-state fermentation， and the volatile flavor components of quinoa wine and sorghum wine were detected by gas chromatography-mass spectrometry(GC-MS) and gas-ion mobility spectrometry(GC-IMS). The results showed that the total volatile flavor components detected by GC-MS in quinoa wine were 49 and sorghum wine was 29. 23 and 12 unique substances were detected in quinoa wine by GC-MS and GC-IMS， respectively， among which D-limonene， α-Gurjunene， caryophyllene， ethyl isobutyrate， isobutyl propionate， isoamyl butyrate， methyl 2-methylbutanoate and (E)-2-hexenal were the characteristic volatile components in quinoa wine； Isoamyl alcohol， (s)-(-)-ethyl lactate， 1-propanol， ethyl octanoate， ethyl acetate， ethyl butyrate and 2-dimethylpyrazine were high volatile flavor components common to both quinoa wine and sorghum wine； the relative levels of isobutyl alcohol and isoamyl alcohol with undesirable odor were lower in quinoa wine compared to sorghum wine. The sensory evaluation showed that the quinoa wine had more prominent grain and fruit aromas and a fuller， rounder body， which may be attributed to the unique volatile components at play. This study provides analytical ideas for quinoa wine development.

Abstract:In order to investigate the substance transformation of polyphenols in black tea before and after processing， ultra-performance liquid chromatography-high resolution mass spectrometry combined with mass spectrometry molecular network were used to analyze the tea samples before and after processing. In this study， a total of 250 polyphenolic compounds were detected from tea samples before and after processing， including 115 catechins， 62 phenolic acids and 73 flavonoids. Among the 201 compounds， 174 compounds showed significant differences in content (P<0.01). 49 compounds were newly generated after black tea processing， among which 21 were theaflavins.

Abstract:The effects of marinating on the volatile flavor compounds of Guizhou Sansui characteristic marinated duck was investigated by solid phase microextraction and gas chromatography-mass spectrometry(SPME-GC-MS)， combined with relative odor activity value (ROAV)， cluster analysis (CA) and principal component analysis (PCA) were used to analyze the samples marinated for 0 min， 60 min and 120 min in order to determine the key volatile flavor substances of marinated duck in the process of marinating. The results showed that 67， 94 and 100 volatile flavor compounds， including hydrocarbons， aldehydes， alcohols， esters， ethers and sulfur-containing heterocycles were detected at 0 min， 60 min and 120 min， the richness of flavor increased significantly during the marinating process(P<0.05). Relative odor activity value (ROAV) and cluster analysis (CA) found that there are 28 key flavor substances in the marinating process (ROAV>1). Principal component analysis(PCA) indicated that linalool， hexanal， nonanal， octanal， n-heptanaldehyde， D-limonene， α-pinene， γ-butyrolactone and 1-octene-3-alcohol are the key flavor compounds in different marination stages. Benzaldehyde and phenylacetaldehyde were the characteristic aroma compounds of the samples marinated for 0 min. Trans-2-octenaldehyde were the characteristic aroma compounds of the samples marinated for 60 min. Dodecaldehyde， decanal， 3-hydroxy-2-butanone， terpinene， α-caryophyllene， laurene， α-terpineol， 6-methyl-5-heptene-2-one， terpene oleene， trans basilene were the characteristic aroma compounds of the samples marinated for 120 min. With the extension of marinating time， the types of key flavor compounds of Sansui characteristic marinated duck are more abundant， and the main flavor compounds such as hydrocarbons， ketones and alcohols are added to improve the overall flavor of the Sansui characteristic marinated duck.

Abstract:In the study， petroleum ether， ethyl acetate， n-butanol and water with different polar solvents were used to the water-extracted supernatant of Grifola frondosa. The main functional components of different polar extracts were compared， and the antioxidant activities were compared by three methods: 1，1-Diphenyl-2-trinitrophenylhydrazine (DPPH)， 2，2-diazo-bis(3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS+)， hydroxyl (OH) free radical. The results showed that the polyphenol and protein contents of the n-butanol extract were the highest at 0.36% and 38.75%， respectively. The highest flavonoid content in petroleum ether and ethyl acetate extracts was 0.05%. The contents of triterpenoids and sterols in petroleum ether extract were 6.32% and 15.88%， respectively. The highest polysaccharide content in water extract was 30.11%. N-butanol extract showed the strongest antioxidant activity， and polyphenols may be the main component of antioxidant activity. Thirteen polyphenols and their derivatives were identified by LC-MS. This provides a theoretical basis for the development of Grifola frondosa functional food or health products.

Abstract:In this study， electronic nose (E-nose)， electronic tongue (E-tongue) and Headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with relative odor activity value (ROAV) were used to evaluate the volatile components and key aroma components of Xinjiang pilaf. The results show that the electronic nose can effectively distinguish the volatile components in different Xinjiang pilaf； the electronic tongue cannot effectively distinguish the taste of different Xinjiang pilaf. A total of 132 volatile compounds were detected by HS-SPME-GC-MS， including 25 alkanes， 16 olefins， 27 aldehydes， 26 alcohols， 11 ketones， 9 esters， 15 phenols and 3 other compounds. A total of 39 common volatile flavor compounds were detected. Combined with ROAV analysis， Myrcene， Caryophyllene， (E，Z)-2，4-decadienal， 4-(1-methylethyl)-Benzaldehyde， 4-Isopropylcyclohexa-1，3-dienecarbaldehyde， (E，E)-2， 4-decadienal， (E)-2-Decenal， Nonanal， (E)-2-nonenal， beta-Ionone were the key aroma substance of Xinjiang pilaf.

Abstract:With the rapid growth of the global population and the increasing demand for high-quality protein， the 'gap' in traditional animal and plant protein resources has gradually become apparent. Developing new sources of alternative proteins is of great strategic significance. The application of alternative protein raw materials in the production of simulated meat can solve problems such as insufficient supply of traditional meat， high resource consumption and waste emissions， and animal welfare. Fungal protein， as an emerging alternative protein， has the advantages of balanced and comprehensive amino acid composition， rich dietary fiber， and less saturated fatty acid. Additionally， the fibrous structure of fungal mycelium can effectively restore meat texture， making it a promising candidate for developing simulated meat. This article reviews the types， production processes， nutritional and safety characteristics of fungal proteins， as well as the research progress of simulated meat processing technology. The current market status， challenges， and future development directions of fungal protein based meat analogues are also analyzed.

Abstract:During the process of food storage and circulation， there will be different degrees of quality deterioration. With the improvement of people's attention to food quality and safety， it is of great significance to carry out quality prediction research in the process of food storage and transportation for quality control. This paper reviews the research progress of machine learning in food storage quality prediction， including conventional quality prediction methods and limitations， and then focuses on the rapid development and wide application of integrated learning and artificial neural network algorithms， and prediction performance evaluation methods in recent years. Finally， it summarizes and looks forward to the future development trend of machine learning in the food field， and provides relevant references for the development of food science cross research.

Abstract:As the elderly population is growing at a fast pace， China has become the top one with the world's largest population of elderly people. Aging is often accompanied by deterioration of the oral physiology and eating capabilities， resulting in loss of appetite and decrease of food intake. As a result， the nutritional， physical and mental health status of these older adults is at stake. Therefore， how to design more age-friendly food products with textural and nutritional improved properties is the key challenge in food industry. However， in China， the food industry focusing on age-friendly food is still in a very early stage and the supply of special food is far from meeting the need of elderly people. The aim of this review was expected to discuss the current research progress of special foods for the elderly and the dietary needs of the elderly， and to propose food design strategies of special foods for the elderly in terms of nutrition， texture， packaging， and labeling. Moreover， this review was focused on the research area of food oral processing and the application of modern new food processing technology to provide potential approaches for better designing special foods for the elderly in China.

Abstract:Food has always been a resource on which people live， and protein is an important part of food. Protein not only provides people with daily energy， but also provides a habitat for some fungi in food. If not controlled， it will not only lead to food corruption and deterioration， but also pose a great threat to human food safety. In traditional methods， people usually kill the surface of food or add bacteriostatic agents in the process of food processing to inhibit the growth of bacteria. However， these methods also have obvious drawbacks， that is， the chemicals in the disinfectant will remain on the food surface and be ingested by people， which does not meet the high standard requirements of food safety. With the gradual maturity of the research on the direction of protein modification， many methods of protein modification have also entered the public's attention. The physical field modification of protein is one of many methods， which is undoubtedly more novel than some traditional methods and safer than traditional disinfection methods. Some recent studies have also confirmed that the antibacterial activity of proteins modified by physical fields is indeed improved. Therefore， while combing the related research on improving food antibacterial property by physical field modified protein， this paper is also intended to provide new ideas and innovations for people's research in this area.

Abstract:Fermentation is an important strategy for food preservation， and fermented foods are the result of the joint action of a diverse range of microorganisms that impart a special flavor to the product. Quorum sensing system (QS) is a highly targeted and universal microbial regulation mechanism， which is based on population density and regulates the behavior of multiple gene expressions by sensing the concentration of autoinducers (AI). According to different types of AIs， QS systems are classified into three major categories. The article provided an overview of fermented foods and the three major types of QS systems. The positive effects of QS systems on microbial co-culture， the prevention and control of harmful microorganisms， and the effects on fermented food quality were described. From the perspective of QS， the article broadens the research ideas of microorganisms in fermented foods， and lays the foundation for further improving the application of microorganisms in food production.

Abstract:Taste assessment involves five basic tastes: sour， sweet， bitter， fresh and salty. It is the basis for mammals to feel the external environment. The taste sensing system can quickly， sensitively and specifically obtain taste information from complex mixtures， It is considered to be one of the best "chemical detector" in nature. The inherent advantages of biological taste provide inspiration for the development of bionic taste sensing technology. The bioelectronic tongue based on taste system has been widely used in the fields of food safety， drug development and disease diagnosis. Combined with the research results in recent years， this paper makes a comprehensive review on the taste conduction mechanism and the development and research of bioelectronic tongue， and summarizes the practical application of bioelectronic tongue based on taste system in taste measurement. Its future development and application prospects are discussed.

Abstract:The quality of food has a crucial relationship with human health， so the rapid and accurate detection of food quality has always attracted much attention. Olfactory visualization technology is a new type of food testing technology， which not only has the advantages of being fast， sensitive， and not easily affected by the environment， but also can intuitively judge the quality of food through color changes. However， due to the influence of complex surrounding factors， olfactory visualization technology cannot be used as a standard food quality testing method. In this paper， we review the basic principles and components of olfactory visualization techniques and their applications in the detection of meat， spices， beverages， grains and other foodstuffs at home and abroad. The impact of the technology on them is analyzed in depth from a multidimensional perspective， the main problems faced are summarized， and the future development trend is foreseen. It provides theoretical references for expanding its application scope and realizing the functionalization， intelligence and informatization of food safety and quality testing.

Abstract:Sea cucumber has high nutritional and medicinal value， is characterized by a marine echinoderm with high protein and low lipid. In recent years， a growing number of sea cucumber peptides with bioactive functions have been discovered， including antioxidant， anti-aging， learning and memory improvement， anti-fatigue， anti-hypertensive， antimicrobial， antitumor， immune-regulating， hypoglycemic， as well as anti-inflammatory activities， and regulate the physiological function through multiple ways. This paper aimed to review biological functions of sea cucumber peptides and their potential regulatory mechanisms. Furthermore， main application fields and research directions are presented， which will provide a theoretical basis for the development and utilization of sea cucumber peptides in the future.

Abstract:Basic electrolyzed water is prepared by electrolyzing dilute salt solution， which is widely used in the research of food field with the advantages of green safety， broad-spectrum sterilization， efficient preservation and low price. BEW possesses high pH and reduction potential， and strong penetration， which makes it show great application potential in the fields of food sterilization， processing， preservation and extraction. This paper reviews the application and research progress of BEW in food in recent years， and focuses on the latest progress of the application of BEW in food safety control， food preservation application and food active substance extraction， in order to provide theoretical guidance and methodological reference for the efficient utilization and further research of BEW in the field of food.

Abstract:Under the guidance of the 'Greater Food' strategy， a number of scientific research platforms which are committed to focusing on the frontier interdisciplinary disciplines in the food field， leading the world in basic food science research， developing disruptive technologies in the food sector are abruptly rising， and becoming an effective force to serve the strategy of 'healthy China'. This article expounds the construction path of a scientific research platform serving 'healthy China' strategy from the aspects of connotation of the future food era， interdisciplinary integration， major scientific and technological breakthroughs， and collaborative industrialization.

Abstract:With the continuous expansion of the domestic snack food market， it is crucial to understand the key factors affecting consumer preferences and guide product improvement. This article focused on spicy strips with different brands， which carried out the evaluation of key sensory attributes for sensory evaluation groups and consumers. Penalty analysis preliminarily explored the sensory attributes and improvement directions of each product， and studied the taste characteristics through ANOVA and correlation analysis. The preference mapping was deeply processed and characterized the results of QDA and consumer preference. And it also verified the reliability of the Penalty analysis. The results showed that the sensory attributes and preferences of the six brands of spicy strips were both significantly different. Penalty analysis proposed key sensory attributes that influence consumers' preferences and identified improvement strategies for sensory attributes of 6 spicy strip samples preliminary. It was found that the preference rate of consumers for samples DLB， DDR， ZCL and WLQ was 50%-80% through preference map technology， and it was speculated that sweetness， chewiness and oily juice were the sensory attributes that could potentially affected consumers' preferences. The preference rate of consumers for GSW and HMH was 20%-30%， speculating that salty， spicy， numb， and essence spicery were the sensory attributes that potentially affected consumer preferences. By comparing the results of QDA， Penalty analysis and preference graph， it was found that the overall conclusion was consistent， and the final optimization and improvement strategy was determined by combining the three conclusions. The sensory attribute improvement model of spicy strips established in this article can provide a reference for the improvement of taste characteristics of spicy strips and the development of new products.