Abstract:Dendrobium officinale is a perennial epiphytic herb of Dendrobium genus of Orchidaceae， which enjoys the reputation of 'life-saving herb' in China's folklore. It contains polysaccharides， alkaloids， flavonoids and other bioactive ingredients， which together make it good at improving immunity， balancing inflammation， regulating glucose and lipid metabolism， and promoting the health of gastrointestinal tract， ect. On November 9 2023， Dendrobium was officially added as 'food and medicine of the same origin' substance， which expanded its application prospects in the field of healthy food by the National Health and Health Commission of the People's Republic of China and State Administration for Market Regulation. This paper summarized the research history of Dendrobium officinale from 'cultivation and planting' to 'its functional components' and 'its processing characteristics'， and also summarized the research progress of its main functional substance， Dendrobium officinale polysaccharide， in all aspects. At the same time， this paper also elaborated the current situation of Dendrobium herb deep-processing， and analyzed the key problem and future direction of Dendrobium officinale industrialization， in order to provide reference for the innovative application of Dendrobium officinale in the health industry.

Abstract:Phycocyanin (PC) is a kind of natural pigment protein complex derived from marine algae. It is also a type of important food functional factor with anti-cancer， anti-inflammatory， and immune-enhancing activities， and has been widely used in functional food， medicine and cosmetics. Phycocyanin has been proven to inhibit the activity of non-small cell lung cancer (NSCLC) cells， but the underlying regulatory mechanism is not fully understood. This study focused on miR-642a-3p， and investigated the potential regulating mechanism of phycocyanin in NSCLC cells. The results showed that phycocyanin upregulated the expression level of miR-642a-3p in four NSCLC cells(A549， H1299， H460 and LTEP-a2). Overexpression of miR-642a-3p levels significantly inhibited the proliferation， migration and unanchored growth of four cells in vitro. In addition， transfection of miRNA inhibitors to interfere with the expression of miR-642a-3p could enhance cell viability to a certain extent. This study preliminarily revealed that the up-regulation expression of miR-642a-3p was involved in the regulation of inhibiting NSCLC cell viabilities by phycocyanin， which could lay a scientific theoretical basis for the in-depth study and utilization of phycocyanin.

Abstract:Objective: To investigate the genetic stability of Lacticaseibacillus rhamnosus Probio-M9 (L. rhamnosus Probio-M9) during continuous passage. Methods: The morphological changes， carbohydrate utilization capacity， activity and metabolic characteristics of L. rhamnosus Probio-M9 were compared in the 0， 25， 50， 75 and 100 passages of the probiotic strain. At the same time， comparative genomics was used to analyze the changes of genome level during the continuous culture of 100 generations. Results: There were no significant changes (P > 0.05) in phenotypic characteristics and metabolic characteristics of L. rhamnosus Probio-M9 during 100 generations of continuous culture， and the phenotypic characteristics were stable， and the strain activity was maintained well. At the same time， using the genome of L. rhamnosus Probio-M9 as the reference sequence， 15 strains of different generations were sequenced， and the genome size and GC content showed no significant difference between the 15 strains cultured continuously and L. rhamnosus Probio-M9. Phylogenetic relationships showed that the 15 strains were closely related to the original genome. From the identified SNP loci， no mutation locus with stable inheritance was found in every two generations， and the collinear strain was good. The mutation level of the coding gene at the genome level confirmed that L. rhamnosus Probio-M9 had stable phenotypic characteristics and metabolic characteristics during the continuous culture of 100 generations. Conclusion: L. rhamnosus Probio-M9 has good genetic stability during continuous passage， which provides a theoretical basis for further development， research and industrialization of L. rhamnosus Probio-M9.

Abstract:Short chain-galactooligosaccharides (SC-GOS) is an effective proliferation factor of Bifidobacteria. Seven strains of Bifidobacteria with high utilization of SC-GOS were screened from infant fecal samples， the result of 16S rDNA identification was that one was Bifidobacterium longum subsp. infantis BI_Y46， 2 B. pseudocatenulatum (BP_Y43， BP_YA)， 2 B. bifidum (BB_Y22， BB_S7) and 2 strains of B. longum (BL_S34， BL_H26). Compared with B. infantis M63 and B. infantis ATCC 15697， the morphology of the strains was observed and the probiotic characteristics were analyzed. Thus， the probiotics with application potential were screened. The results showed that BI_Y46 had special morphology with bifurcated fimbriae， and the exopolysaccharide yield of BB_Y22 and BP_Y43 was higher than 0.45 mg/mL. The surface protein content of BL_H26 was (0.74±0.07) mg/mL， the content of BB_S7 and BB_Y22 was between 0.35-0.45 mg/mL. Whereas， BP_Y43 and BB_Y22 had strong surface hydrophobicity and self-aggregation ability. BB_Y22 and BI_Y46 showed strong tolerance to the stimulation of bile salt and gastric juice. The supernatant of BI_Y46 and BB_S7 had strong inhibiting effect on Escherichia coli ATCC 25922. In summary， B. infantis BI_Y46， B. bifidum BB_Y22 and B. pseudocatenulatum BP_Y43 had good probiotic potential and provide some reference for the development of products containing galactoseoligosaccharides and Bifidobacterium.

Abstract:The purpose of this study was to explore the regulatory role of arginine decarboxylase (ADC) in core browning of Yali pear. Using Yali pear as material， the arginine decarboxylase of Pyrus bretschneideri (PbADC) was identified， and the bioinformation of PbADC and the gene expression pattern of PbADC were analyzed. The results showed that the PbADC gene was successfully identified and contained a complete open reading frame of 2 193 bp that encoding 730 amino acids. The phylogenetic analysis showed that PbADC was very closely to ADC of Pyrus betulifolia， Malus domestica， Pyrus ussuriensis × Pyrus communis and Malus hupehensis， and the multi alignment analysis showed that PbADC containing the complete Orn_Arg_deC_N domain， the binding site of pyridoxal 2-phosphate of ADC family and two important enzyme activity sites. Bioinformatics analysis showed that PbADC was a hydrophilic unstable protein with theoretical isoelectric point of 5.23 and molecular weight of 78.403 ku， which was hydrophilic and non-transmembrane without signal peptide， and α-helix and random coil were the main secondary structure of PbADC. The core browning index of rapid cooling treatment group was higher than that of slow cooling treatment group. Quantitative PCR and enzyme activity results showed that the expression of PbADC increased at the early storange period and then decreased during the browning of Yali pear， and the change of ADC enzyme activity was consistent with the gene expression level. This study clarified the bioinformatics characteristics of PbADC protein and the differential expression of PbADC gene during storage， which provided a theoretical basis for further research on the mechanism of postharvest browning of Yali pear.

Abstract:In this study， quorum-sensing quenching activity of Lactobacillus crustorum ZHG2-1 was verified with the Chromobacterium violaceum CV026 as a indicator strain. Based on the change of biofilm， phenotypes of spoilage factors and the expression levels of related genes， the quorum sensing quenching mechanism of Lb. crustorum ZHG2-1 on P. fluorescens was detected. The results showed that the degradation rate of cell-free supernatant from strain ZHG2-1 to P. fluorescens AHLs reached 100%. The sub-inhibitory concentration (1.0， 2.0， 3.0 mg/mL) of strain ZHG2-1 crude extract could inhibit and remove the biofilm of P. fluorescens, and the inhibition rate and clearance rate reached 9.66%-31.32% and 28.62%-62.82%, respectively. In addition, the inhibition rate of strain ZHG2-1 crude extract with sub-inhibitory concentration on P. fluorescens spoilage factors (exopolysaccharides， proteases， lipases， biogenic amines) reached 7.23%-100%. Meanwhile， the inhibition rate was mass concentration-dependent. Scanning electron microscope showed that the sub-inhibitory concentration of strain ZHG2-1 crude extract treatment significantly reduced the amount of biofilm and the bacterial colonies were in a dispersed state. The results of qRT-PCR showed that the crude extract of strain ZHG2-1 down-regulated the quorum-sensing genes rhlI and rhlR of P. fluorescens by 0.93 and 0.99， respectively， and the expression levels of aprX， algA， orm， flgA， ldcA and other biofilm and spoilage genes was significantly inhibited. The results indicated that Lb. crustorum interfered with the expression of quorum-sensing genes of P. fluorescens， thereby affecting the production of biofilm and spoilage factors.

Abstract:To investigate tentatively the inhibition mechanism of eight monoalkylphenol flavor compounds (EMFC)， which were listed in the positive list of Chinese food additive use standard (GB2760-2014)， against Escherichia coli (EC)， and to determine the relation of the inhibition effect to the structure of EMFC， spectrophotometry， electrical conductivity and scanning electron microscope were used in this present study. The results showed all of the EMFC at the concentrations from 0.195 mg/mL to 0.781 mg/mL had effects on the production curve of EC in different degrees； EMFC enhanced the permeability of cell membrane， resulting in the leakage of intracellular ions； with the increasing of EMFC concentrations， the release of cell constituents increased. The results of scanning electron microscope indicated all of the EMFC at their minimum inhibitory concentration could damage the cell membrane and cell wall of EC to a certain extent， and make EC not the normal cell morphology but bends， folds， and depressions. The inhibition effects of EMFC on EC were associated with the structure of EMFC； the efficiency of propylphenol was better than that of ethylphenol， ethylphenol better than methylphenol. When alkyl group attached to benzene ring was same， alkylphenol whose alkyl group was at the para-position of hydroxyl group had the best bacteriostatic activity. EMFC could inhibit the growth of EC by damaging the cell membrane and enhancing the cell membrane permeability. The result obtained lays a theoretical basis for developing food preservatives by using phenol flavor compounds.

Abstract:Pork myofibrillar protein(MP) was selected as the main research material. The Fenton oxidation system was employed to replicate the oxidation conditions of meat items， and curcumin with different concentrations (0， 5， 10， 15， 20 μmol/L) was added to it. Changes in amino acid side chain， secondary structure， tertiary structure and solubility of protein were analyzed. To explore the inhibitory effect of curcumin on the oxidation of pork myofibrillar protein at different concentrations and its specific effect on protein structure. The results showed that curcumin had good free radical scavenging performance and could effectively slow the protein oxidation and structural changes caused by hydroxyl radicals， and this inhibition was proportional to the concentration of curcumin in a specific concentration range(5-20 μmol/L). Compared with the oxidation group， the curcumin treatment group significantly inhibited the formation of carbonyl groups and the increase of surface hydrophobicity， the curcumin treatment group of 20 μmol/L had the inhibition rates of 2.62% and 51.78%， respectively (P<0.05)， can also significantly alleviate the decline of sulfhydryl， free amino and solubility(P<0.05)， the inhibition rates were 80.02%， 59.34%， 70.84%， respectively， and the addition of curcumin can promote the MP tertiary structure unfolding ， can also alleviate the secondary structure changes caused by hydroxyl radicals. Therefore， curcumin can interact with MP to alleviate its oxidative deterioration and structural changes， and has a good effect on the quality and preservation of meat products.

Abstract:The effect of hydration degree on the structure of V-type starch and its thymol inclusion complex was investigated by encapsulating the thymol into V-type starch treated at different hydration times. The X-ray diffraction (XRD)， Fourier transform infrared (FTIR) spectroscopy， and differential calorimetry (DSC) were used to characterize V-type starch and its inclusion complexes， and the content of thymol was determined by gas chromatography. The results showed that the successful complexation between V-type starches and thymol was formed， and the inclusion complex exhibited an endotherm with peak temperature at 118 ℃. The inclusion complex after hydration for 72 h exhibited the largest endothermic peak with ΔH of (7.31 ± 0.29) J/g. The XRD results showed that the crystallinity of V-type starch increased from 35.2% to 41.1% as the hydration time increased from 0 h to 72 h. The water in internal and external of V-type starch granule reached balance after 72 h of hydration， and the water coating on the surface of the granules gradually disappeared and the particle roughness increased. The gas chromatography showed that the thymol content in the inclusion complex was positively correlated with hydration time. The research results provide a theoretical basis for the development of microcapsule wall materials of natural polymer materials， and are of great significance for the innovation and development of high-value applications of flavor compounds.

Abstract:Four phenolic acids [caffeic acid (CA)， p-coumaric acid (p-CA)， syringic acid (SA)， and gallic acid (GA)] were selected and added to high-gluten wheat flour to investigate the effects of small molecule phenolic substances on the physicochemical properties of dough. Rapid viscometer was used to determine the pasting properties of the dough， Mixolab to determine the thermo-mechanical properties of the dough， rheometer to determine the rheological properties of the gluten proteins， and differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) to determine the thermodynamic properties of the gluten proteins. The results showed that the addition of p-CA at 0.1% was favorable for the dough to maintain a high termination viscosity (4 399 cp)， and the addition of CA and SA inhibited the aging of starch. CA， p-CA， GA， and SA could significantly increase (P<0.05) the water absorption of dough and reduce the stabilization time， among which the highest water absorption of 63.08% was observed when 0.3% of GA was added. However， the addition of the four phenolic acids also led to the disruption of the rearrangement of starch molecules， which resulted in an increase in the degree of gelation. The overall viscoelasticity of gluten proteins was increased by the addition of CA， p-CA， GA， and SA， and all three phenolic acids， except p-CA， resulted in a decrease in the thermal stability of gluten proteins and a weakening of gluten strength. Finally， the microstructures of the doughs also showed that the addition of CA， p-CA， GA， and SA disrupted the originally homogeneous and dense microstructure of gluten proteins， and the extent of the disruption increased with the increase in the amount of phenolic acid added.

Abstract:The changes of water-holding capacity， hardness， elasticity， soluble protein content， microscopic morphology and structure of soy protein isolate-dextran conjugate gels crosslinked by transglutaminase (TG) at different mass concentration(30，40，50，60 mg/mL) during freeze-thaw cycling (FTC) were explored. The Maillard reaction between soy protein isolate and dextran was confirmed by the results of SDS-PAGE electrophoresis. At the same time，soy protein isolate-dextran conjugates (SPI-D) were generated. With the Maillard reaction process proceeded， the grafting degree of SPI-D increased firstly and then decreased， finally reached the maximum of 12.54% at a mass concentration of 50 mg/mL. Surface hydrophobicity and fluorescence spectroscopy proved that the structure of the protein unfolded， flexibility and disorder enhanced， which was beneficial to the freeze-thaw stability. Compared with the control， the water-holding capacity of SPI-D， SPI and dextran mixture(SPI+D) and SPI gel decreased by 32.46%， 42.81% and 44.98%， the hardness increased by 124.66%， 271.51% and 343.38%， and the elasticity increased by 4.38%， 9.58% and 11.76%， the soluble protein content decreased by 2.05%， 3.61% and 7.17%， respectively， after 5 FTCs. Among these experimental groups，SPI-D gel showed the smallest change in all indicators and the best freeze-thaw stability， the microstructure of the gel was characterized by the scanning electron microscopy images， compared with SPI + D gel and SPI gel， SPI-D gel had smaller pores and more uniform organization. The above findings suggested that Maillard reaction was an effective technical means to enhance the freeze-thaw stability of soy protein isolate gel by enzyme method.

Abstract:Lactic acid bacteria can be inoculated at different stages of alcoholic fermentation during winemaking， but the influence of inoculation timing of indigenous lactic acid bacteria on wine is not well defined. The aim of this study was to investigate the influence of inoculation timing of Chinese indigenous lactic acid bacteria and commercial yeast on physiochemical parameters and the color of synthetic red grape juice. Three selected lactic acid bacteria 6-20， GZC3 and V22 were used to ferment the synthetic medium with Saccharomyces cerevisiae CECA. Two inoculation strategies were applied in the fermentation， including simultaneous and sequential inoculation， with single fermentation as the control. The sequential inoculation includes inoculating Saccharomyces cerevisiae 2 and 4 days prior to inoculating lactic acid bacteria and vice versa. The fermentation process was monitored by regularly measuring residual sugar， malic acid， and the colony numbers of both yeast and bacteria. After completion of fermentation， basic physiochemical parameters such as total acidity， volatile acidity， and pH were measured. Following this， total polyphenols and anthocyanins were determined by the Forlin phenol method and pH-differential method， respectively. Color parameters were then obtained through CIELab color space. Further， the correlation between color parameters and anthocyanin content was analyzed to evaluate wine color characteristics. Finally， Adobe Photoshop CS6 software was used to intuitively simulate the color of each wine sample. Results showed that there were significant differences in fermentation characteristics of simulated wine fermented by different inoculation strategies and these were strain-dependent. All strain pairs successfully completed alcohol fermentation (AF) in approximately 15 days. Malolactic fermentation (MLF) occurs simultaneously with or earlier than AF， depending on the inoculation timing of lactic acid bacteria. Not surprisingly， MLF was completed together with AF， or shortly after the depletion of residual sugar. Early inoculation of lactic acid bacteria was more conducive to MLF， whilst inoculation of yeast prior to lactic acid bacteria was more beneficial to AF. Particularly for CECA/6-20 mixed fermentations， AF took 2-4 days less when inoculating CECA prior to the inoculation of 6-20 compared to the rest inoculation strategies. Simultaneous inoculation of both S. cerevisiae and lactic acid bacteria had no significant effect on overall fermentation duration. The basic physicochemical parameters of all wine samples met the relevant national wine standards. In addition， the total phenol content and total anthocyanin level of most fermentation groups decreased significantly， and there was a significant correlation between these two parameters， though their correlation to CIELab color parameters was weak. With regard to wine colors， sequential inoculation resulted in darker colors compared to the simultaneous inoculation group. Interestingly， wine color was also species-specific， in particular， samples inoculated with Oenococcus oeni GZC3 were generally darker than that inoculated with Lactobacillus plantarum V22 and 6-20. To conclude， this study clearly proved that our selected indigenous lactic acid bacteria strains were compatible with the commercial yeast CECA regardless of inoculation timing， thereby reducing the overall fermentation duration. Co-fermentation of yeast and bacteria would impact certain physiochemical parameters of wine. This study provides theoretical support and reference for efficient local production of high-quality red wine as well as helps promote the wide application of indigenous wine in China.

Abstract:In order to investigate the effects of moromi Staphylococcus spp. on the fermentation of high-salt liquid-state soy sauce， three Staphylococcus spp. (JL04， JL15， and JL17) with good acid-producing performance were screened from high-salt liquid-state moromi using acid-production as an index， which were identified as S. comdimenti， S. piscifermentans and S. carnosus， respectively. The three strains were added to the 15th day high-salt liquid-state moromi for a 60 days fermentation， and analysis of the changes for reducing sugar， total acid and ammonia nitrogen during the fermentation process showed that all three strains could accelerate the utilization of reducing sugar in moromi and increase the content of total acid and ammonia nitrogen. Among them， the total acid of fermented soy sauce added with JL04 was the highest， which was 15.61 g/L； and the ammonia nitrogen of fermented soy sauce added with JL17 was the highest， which was 9.31 g/L. HPLC quantitative analysis for 6 organic acids in the fermented soy sauce added with JL04， JL15 and JL17 increased by 37.53%， 24.06% and 25.90%， respectively， compared with the control group， and the main organic acids were acetic acid， lactic acid and succinic acid. GC-MS analysis for the volatile flavor compounds of soy sauce fermented by three strains showed that the content of esters was significantly increased， among which JL04 increased by 116.09%， mainly acetates and lactates， and it was positively correlated with the increase of corresponding organic acids. Sensory scores showed that the addition of three strains could enhance the aroma and taste of soy sauce. The three strains screened from high-salt liquid-state moromi had the characteristics of accumulating organic acids and promoting the synthesis of corresponding esters. They could be used in soy sauce fermentation as flavor bacteria to impart suitable sour taste， enrich taste， and enhance aroma.

Abstract:The effects of arginine low-sodium salt on pork quality were investigated by analyzing the effects of different arginine low-sodium salt additions (arginine replacing 30% NaCl) on the textural characteristics， colour difference， water holding capacity， cooking loss， pH， moisture content， myofibril fragmentation index (MFI)， protein degradation and ultrastructure of pork. The results showed that the use of 4% arginine low-sodium salt significantly improved the elasticity (increased by 60.0%) and chewiness (increased by 48.3%) of pork (P<0.05)， and improved the colour of pork (a increased from 2.9 to 6.3) (P<0.05) compared to pork cured with 3% pure NaCl. It increased the pH from 5.71 to 6.11，decreased the cooking loss of pork from 32.12 g/(100 g) to 23.98 g/(100 g)， but there was no significant change in water holding capacity(P<0.05). The addition of 4% low sodium arginine increased the pork myogenic fibre fragmentation index from 44.73 to 71.40 (P<0.05). Ultrastructural results showed that the I-band， A-band and M-line of myogenic fibres underwent different degrees of degradation. SDS-PAGE electrophoresis profiles showed that actin was significantly degraded to small-molecule components when arginine low sodium salt was added at 2.5%-3.5%. Conclusion: arginine low-sodium salt had the effect of improving the texture， color and tenderness of the pork， which was helpful for improving the quality of pork.

Abstract:In order to study the quality changes and quality influencing factors of duck meat in the process of stewing， this experiment took the moisture content， salt content， yield， hardness， sensory score and comprehensive score that could reflect the product quality as the evaluation indexes， and used single factor test and response surface test design to study the stewing time， brewing soy sauce dosage. The meat to liquid ratio and meat to liquid ratio affected the quality of marinated duck， and the mathematical model of the factors affecting the quality of marinated duck was established. The results showed that the yield of salted duck gradually decreased， the moisture gradually lost， the hardness decreased， the salt content increased， and the sensory score and comprehensive score gradually increased. Stewing time， brewing soy sauce dosage， meat liquid ratio and meat material ratio have different degrees of influence on the quality of Sansui characteristic stewed duck. The order of size was: meat fo feed ratio > stewing time > meat to liquid ratio > brewing soy sauce dosage. The coefficient of determination R2 of the quadratic polynomial regression equation model was 0.9882， which showed that the experimental data have good experimental correlation with the model， and could be used to study the influencing factors of the quality of Sansui halogen flavored duck. Through comprehensive evaluation， when the brine time was 120 min， the amount of brewing soy sauce was 0.7%， the meat liquid mass ratio was 1∶1.7， and the meat material mass ratio was 1∶0.05， the comprehensive score of the product was 0.75， which was the best quality control point. This study provided an important reference for enterprises to produce Sansui characteristic stewed duck.

Abstract:Objective: The main purpose of this paper was to prepare the immunoactive peptides from Meretrix meretrix Linnaeus (MLIP) by enzymatic hydrolysis， optimize the enzymolysis conditions of MLIP， and studied its immune activity. Method: MLIP was used as raw material， and five commonly used proteases were chosen to hydrolyze. The proliferation rate of RAW264.7 cells was selected as an indicator to screen the most suitable protease for enzymolysis solution. Then， the single factor test was carried out， and three factors with significant impact were selected to optimize the enzymolysis conditions by response surface method， and MLIP was prepared with the optimized process parameters. In addition， this research also studied the effects of different concentrations of MLIP on the relative proliferation rate， cell morphology and NO release of RAW264.7 cells. Results: The proliferation rate results showed that complex protease was the most suitable enzyme to prepare MLIP. The optimal enzymatic parameters obtained by response surface optimization were: pH 6.8， solid-liquid ratio 1∶6.2， enzyme dosage 3 493 U/g， enzymolysis at 45 ℃ for 3 hours. The relative proliferation rate of RAW264.7 cells was predicted to be 71.40%， which were basically the same with the results obtained by verification experiment. In addition， RAW264.7 cells showed the best proliferation promoting effect when the concentration of MLIP was 0.4 mg/mL. All dose of MLIP caused differentiation to varying degrees of cell differentiation and had a certain promoting effect on the release of NO of RAW264.7 cells. Conclusion: The results indicated that the MLIP exhibit desirable immune activity， which might provide reference for the preparation and further study of the MLIP.

Abstract:The optimum process of extruded instant porridge was studied with composite grain powder as raw material. Based on the previous single factor experiment results， the process of extruded instant porridge was optimized by box Behnken design response surface method. The quality of extruded instant porridge was evaluated by taking physical and chemical properties， sensory score， texture properties and digestibility of protein starch as investigation indexes. The structure of instant porridge before and after extrusion was studied by Fourier infrared spectroscopy and X-ray diffraction. The results showed that the best technology of extruding instant porridge was as follows: Screw speed 250 r/min， extrusion temperature 170 ℃， water addition 19%. In the validation test， the coefficient of variation is between 0-12%， and the optimized process conditions of instant porridge have good reproducibility， indicating that the process parameters optimized by response surface are reliable. Under these conditions， The protein digestibility and starch digestibility of the instant porridge increased by 12.570% and 12.602%， respectively， after extrusion compared with that before extrusion. Fourier transform infrared spectroscopy analysis showed that the structure of main functional groups did not change significantly before and after extrusion， and the intensity of some characteristic peaks decreased after extrusion. X-ray diffraction scanning analysis showed that the crystal configuration of instant porridge changed before and after extrusion. After extrusion， the quality of instant porridge was improved and the microstructure changed.

Abstract:A multivariate linear regression model between the coupling factor and the quality index of oat noodles in the drying system was established， and the drying coupling factor predicted the quality index of oat noodles. Taking the quality index of oat noodles as the dependent variables， and the coupling factors (temperature， air absolute water potential， air absolute water potential and accumulated temperature) as the independent variables， through multiple linear regression， the prediction model of each quality index of oat noodles was established， evaluated and verified. The results showed that the established quality index regression models of optimal cooking time， cooking loss， cooking water absorption， ductility， hardness， chewability， adhesion， flexural strength， breaking distance， acidity and fatty acid value， were significant (P < 0.01)， and the model's coefficients R2 for quality index prediction were 0.8075， 0.9981， 0.8485， 0.8354， 0.8118， 0.8194， 0.8030， 0.8416， 0.8838， 0.8100 and 0.8888， respectively. The drying coupling factor can be used to predict the quality index of oat noodles， and the study provided a theoretical basis for the quality control of oat noodles in the drying process.

Abstract:This article studied the effect of different volume fractions of CO₂ (4% CO₂， 8% CO₂， 12% CO₂) on chlorophyll degradation of soybeans under 5% O₂ controlled atmosphere storage conditions. The results showed that controlled atmosphere storage could effectively delay the yellowing of soybeans and the decomposition of chloroplast ultrastructure， maintaining good appearance quality. During the storage process of soybeans， CO₂ treatment significantly inhibited the increase in the content of Chd a and Phb a in the deprotent medium， delaying the degradation of chlorophyll. On the 20th day of storage， the chlorophyll a/b content in the 8% CO₂ storage group was 40.32 μg/g and 20.37 μg/g， respectively， significantly higher than that in the control group. At the same time， the CO₂ storage group significantly inactivated the activities of MDCase and PPH， and at the end of storage， the enzyme activity of the 8% CO₂ storage group decreased by 19.8% and 7.2% compared to the control group， respectively. Therefore， the best effect of soybeans is achieved under 5% O₂+8% CO₂ controlled atmosphere storage conditions.

Abstract:To investigate the effect of hypobaric storage on the ripeness progress and antioxidant capacity of 'Nanguo' pear， pears at commercial ripeness stage were used as experimental materials and stored under 2 kPa and 25 kPa low pressure conditions for one month before being transferred to the condition of (20±2) ℃ and 101 kPa to simulate the ripening progress and observe their ripening quality and antioxidant capacity. The results showed that 2 kPa and 25 kPa hypobaric conditions could maintain the ripening quality of 'Nanguo' pears， the yellowing of the fruit peel， and the reduction of fruit firmness， total phenolic and flavonoid contents were inhibited. The contents of soluble solids and titratable acids were maintained well. The appearance of respiratory peak and decreased ethylene release were delayed. Meanwhile， the activity of polyphenol oxidase was decreased， and peroxidase activity was increased. Notably， 2 kPa hypobaric storage at(4±2) ℃ performed better to delay the ripening process of 'Nanguo' pears after storage， and their antioxidant capacity was also maintained well.

Abstract:In order to investigate the bactericidal conditions of cold atmospheric plasma (CAP) on Pseudomonas fluorescen in modified atmosphere packaging (MAP) and the bactericidal mechanism of CAP in MAP， three factor and three levels orthogonal test was used to optimize the conditions of CAP treatment. The inhibitory mechanism of CAP against Pseudomonas fluorescens was studied by cell activity， cell wall permeability， cell membrane integrity， antioxidant enzyme activity and microstructure. The results showed that the best sterilization conditions were as follows: Treatment voltage as 50 kV， treatment time as 180 s， modified atmosphere volume ratio as V(N2)∶V(CO₂) = 3∶2， under these conditions， the sterilization rate was 99.49%. The inhibitory mechanism of CAP on Pseudomonas fluorescens showed that cold atmospheric plasma treatment reduced cell activity. The integrity of cell wall and cell membrane was damaged， and the leakage of nucleic acid and protein increased， Na+/K+-ATPase (ATP) content decreased by 13.10 U/mg prot， Propidium iodide (PI) increased， and alkaline phosphatase(AKP) activity decreased to 12.09 King unit/g prot. The activities of antioxidant enzymes superoxide dismutase(SOD) and catalase (CAT) in cells decreased. It changes the shape of the cells， making them stick and sag. In conclusion， cold atmospheric plasma combined with modified atmosphere packaging could effectively inhibit Pseudomonas fluorescens， resulting in cell inactivation or death， and the longer the treatment time， the better the effect.

Abstract:In order to explore the effect of plasma electric field assisted freezing on the quality and freezing process of mutton， the longissimus dorsi muscles of sheep was selected as the experimental material， the effect of the auxiliary plasma electric field of different field strength (1， 3 kV/m and 5 kV/m) on the freezing velocity of mutton and the distribution of ice crystal and the diameter and roundness of ice crystal in the frozen meat were studied， and the thermodynamic theory was used to analyze it. The results showed that the meat samples in the auxiliary 5 kV/m plasma field environment had the shortest time to pass the maximum ice crystal generation zone at -20 ℃ and -35 ℃， 70 min and 40 min， respectively， with significant differences compared with the control group (P < 0.05)； the tissue sections showed the smallest ice crystal area and grain size formed at -35 ℃ assisted 5 kV/m plasma field freezing， and -20 ℃ assisted the roundness of ice crystals was the highest in 5 kV/m plasma field freezing， with a mean value of 0.88， and the above indexes were significantly different from the control group (P < 0.05). The entropy of the system was analyzed using Boltzmann's formula， and the results showed that the entropy of the meat samples frozen by the assisted 5 kV/m plasma electric field was the smallest at -20 °C and -35 °C， with significant differences compared with the control group (P < 0.05). It proved that the auxiliary 5 kV/m plasma electric field could significantly improve the system frozen meat moisture vitrification degree， could make the crystallization process more controllable， the electric field assisted freezing required less energy to improve the subcooling degree， accelerate the freezing rate of meat samples， and the larger the field strength the more significant the effect. Based on the experimental results and energy-saving requirements， it was considered that -20 ℃ assisted 5 kV/m voltage freezing can be used as a new freezing method in production.

Abstract:In order to prolong the shelf life of low-temperature sterilized brine beef， three natural compound additives selected in the early stage were added: Compound spice(CS)， fermented beef flavoring(FBF) and compound natural preservative(CNP). A blank control group (control check， CK) was set up. The sterilization method was boiling water sterilization for 30 min twice (placed at room temperature for 48 h in the middle). The four groups of samples were stored for 150 days (at 10 ℃)， and the changes of sensory quality， physical and chemical indexes and total number of colonies (0， 14， 30， 60， 90， 120 d and 150 d) were measured. The microbial diversity and volatile flavor substances were analyzed on the 90th day. Results showed that during storage， the sensory score(CK: 5.9→5.5， CS: 7.5→7.2， FBF: 6.6→6.2， CNP: 6.4→4.8)， pH value(CK: 6.13→5.74， CS: 6.20→6.05， FBF: 6.18→6.02， CNP: 6.08→5.79) and redness(CK: 13.13→10.23， CS: 12.85→11.66， FBF: 12.23→10.83， CNP: 13.03→11.27) of the products in the four groups decreased， and the TBARS value(CK:0.17 mg/kg→0.42 mg/kg， CS:0.05 mg/kg→0.34 mg/kg， FBF:0.07 mg/kg→0.39 mg/kg， CNP:0.06 mg/kg→0.31 mg/kg) significantly higher at the end of storage than at the beginning of storage, and the overall effect of the CS group was better than the other three groups； 4 groups detected microbial information of 5 phyla and 44 genera with abundance greater than 1%. The dominant phyla were Proteus and Firmicutes， and the number of Firmicutes in CS group was low， and no Bacillus producing biogenic amines was detected. A total of 97 volatile aroma components (CS: 41 > CK: 39 > CNP: 28 > FBF: 25) were detected in the four groups of products. CS group contained compounds with high contribution to flavor. In conclusion， adding spice essential oil can not only prolong the shelf life of products， but also improve the flavor and sensory quality of products.

Abstract:In Chinese market， rice wine is generally packaged in composite film bags， glass bottles， ceramic bottles， plastic buckets and Tetra pak pillows. The barrier properties of different packaging materials are quite different， which have different effects on the flavor of the finished rice wine. In order to detect the change of flavor of rice wine in different packaging materials， the oxygen transmittance and water vapor transmittance of packaging materials， the turbidity of rice wine， the contents of alcohol， ester and aldehyde and the physicochemical indexes were detected by the pressure difference method， coulommeter detection method， cup method， infrared sensor method， turbidity detection method， solid phase microextraction method and the detection methods of alcohol， total acid， total sugar and amino acid nitrogen. It was found that the composite membrane had the worst barrier performance， and the permeability of oxygen and water vapor were very high， which were 1 448 cm3/ (m2·24 h·0.1 MPa) and 2.09 g/(m2·24 h)， respectively. The finished wine had obvious flavor loss within 3-6 months of storage， and a large amount of precipitation appears after storage for 1 year. Therefore， packaging materials with poor barrier properties were not suitable for packaging rice wine. The barrier performance of the plastic drum was in the middle， the oxygen transmission rate was high， but the water vapor transmission rate was low. HDPE plastic bucket would accelerate the oxidation of the wine body， making the turbidity and the content of a variety of volatile substances rise， which was not conducive to maintaining the stability of the flavor， and the shelf life should be set within 1 year. Tetra pak， glass bottles and ceramic bottles had better barrier properties， and lower oxygen and water vapor transmission rates. After storage for 1 year， the precipitation was less， and the flavor content of rice wine remained relatively stable. The physical and chemical indexes and flavor of the glass bottle packaging products stored for 1-17 years were analyzed. The quality of the products was good and they were still suitable for drinking. The content of most flavor substances in rice wine remained stable， but the content of aldehyde compounds increased under the influence of slightly dissolved oxygen. This indicated that the rice wine is stored in glass containers， and the aging changes also occur.

Abstract:In order to establish a shelf-life prediction model that can be applied to a variety of fresh aquatic products at the same time. Using back propagation (BP) neural network model， genetic algorithm-back propagation(GA-BP) neural network model， radial basis function(RBF) neural network model， extreme learning machine (ELM) neural network model and support vector machine for regression (SVR) model to predict the remaining shelf life of four aquatic products respectively. First measure 4 indicators of tuna， salmon， turbot and sea bream at 0， 4 ℃ and 10 ℃， in order to construct training samples and test samples. Including sensory score， total number of colonies， TVB-N value， K value， pH value. After correlation analysis， the pH indicator with the lowest correlation was eliminated， and other indicators were selected as input indicators for each model. Then， determine the network topology and parameters of each model， and train each model. Finally， this study used each model trained to predict the remaining shelf life of the test sample. The result showed that the order of model prediction accuracy was: SVR prediction model > RBF neural network model > GA-BP neural network model > ELM neural network model > BP neural network model. The prediction accuracy of the BP neural network model was the worst， mean square error (MSE) was 9.5127×10-4， mean absolute error (MAE) was 0.0197， mean absolute percentage error(MAPE) was 0.0825， R2 was 0.9766. The prediction accuracy of the SVR prediction model was the best， its prediction error was within 12%， MSE=2.2971×10-4， MAE=0.0128， MAPE=0.0631， R2=0.9944， it could well predict the remaining shelf life of 4 aquatic products. This study provides a theoretical basis for the quality control of aquatic products.

Abstract:Araboxylan (AX) and β-glucan (BG) were extracted and purified from highland barley bran， respectively. It was found that both AX and BG could promote the proliferation of Lactobacillus (L.) plantarum and producing short-chain fatty acids， suggesting potential intestinal probiotic effects of AX and BG. Based on this， Lactobacillus plantarum GIM1.191 was co-microcapsuled with AX (M-AX) and BG (M-BG)， respectively， and their effects on the encapsulation efficiencies， gastrointestinal tolerance and storage were evaluated. The results showed the encapsulation efficiencies of M-AX and M-BG were increased by 1.4 times， and 1.6 times， respectively， compared with the control group (M-S). After simulated gastrointestinal digestion， no viable probiotics was detected in M-S， however， the viable counts of M-AX and M-BG groups were 5.70 and 6.3 lg(CFU/g)， respectively. In addition， AX and BG extended the storage time [viable probiotics counts >6 lg(CFU/g)] from 21 days to 35 days under 4 ℃， and significantly increased the viable probiotics counts at day 14 under 26 ℃. These results will provide theoretical basis and technical support for the high value utilization of highland barley bran.

Abstract:In order to study the effect of high-yield 3-methylbutyraldehyde Lactococcus lactis YN2-1 on the flavor of cheddar cheese， it was added to cheddar cheese as an auxiliary starter culture. The aroma characteristics and volatile compounds of different cheddar cheese samples were compared and analyzed by sensory quantitative description analysis， gas chromatography-mass spectrometry (GC-MS)， gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose. Firstly， in the quantitative descriptive analysis and preference evaluation of the samples， it was found that the cheddar cheese added with Lactococcus lactis YN2-1 had significant aroma differences with the samples without the addition of the bacteria. The cheese added with YN2-1 had higher nut flavor， milk flavor and broth flavor aroma intensity， and its preference score was also higher. GC-MS analysis showed that the content of 3-methylbutyraldehyde in cheese samples added with Lactococcus lactis YN2-1 and matured for 60 d and 120 d was 18.43 μg/kg and 13.96 μg/kg， respectively， which was significantly higher than that of the control group， indicating that the strain has the characteristics of high yield of 3-methylbutyraldehyde in cheddar cheese. The GC-IMS fingerprint was used to visually distinguish the differences in flavor substances between the cheddar cheese added with Lactococcus lactis YN2-1 and the control sample. The contents of 2，3-butanedione， 2-pentanone D， 2-nonanone， 2-methylbutanal， n-propanol， butyl acetate， butyl butyrate， 2，5-dimethylpyrazine， 2-ethyl-3，5-dimethylpyrazine and other substances increased significantly in 60 d or 120 d samples. The contour of the electronic nose radar map between different samples did not overlap， and the discrimination factor (DFA) was higher， indicating that there was a significant difference between the cheese samples added with YN2-1 strain and the control samples， which verified the analysis results of GC-MS and GC-IMS. Conclusion: The addition of this strain could not only increase the content of 3-methylbutyraldehyde， but also contribute to the increase of other flavor substances in cheese. It had a significant improvement effect on the nutty， milky and fruity aroma of cheddar cheese， and has good application potential.

Abstract:The content of fatty acids， amino acids， nucleotides of Tan sheep from Yanchi， Ningxia roasted for different periods were analyzed. The results showed that the total protein content increased from 19.92% to 40.51%， and the total fat content increased from 3.51% to 12.75%. The total fatty acid content increased first(roasted for 0-8 min) and then decreased (roasted for 8-12 min) and increased finally (roasted for 12-20 min) with no significant difference (P>0.05). The content of oleic acid， stearic acid and palmitic acid were the highest among 25 fatty acid identified in all samples and their content exceeds 100 mg/100 g. The content of total hydrolyzed amino acids increased significantly (P<0.05)， increased from 18.5 g/100 g in fresh meat to 49.42 g/100 g. Among all amino acid， lysine， leucine， and cysteine showed the most significant increases. Among the free amino acids， the contents of arginine， alanine and cysteine showed an increasing trend， the contents of histidine showed an decreasing trend and the changes of other free amino acids were not significant(P>0.05). The taste activity value(TAV) method identified that the key umami amino acids in roasted Tan mutton was glutamic acid， the key sweet amino acid was alanine， and the key bitter amino acids were methionine， phenylalanine， valine， and arginine. The main taste substances 5'-adenylic acid and 5'-guanylic acid in roasted Tan mutton increased significantly with increase of time. Collectively， the results of PCA analysis indicated that fatty acids， hydrolyzed amino acids， free amino acids and nucleotides in Tan mutton were significantly different during the roasting process.

Abstract:Objective: To clarify the differences of volatile aroma substances among rice， rice and cooked rice under acidic conditions， and to provide data support for the analysis of volatile flavor differences in the distillation process of nong-flavor liquor. Methods: Headspace solid phase microextraction-comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (HS-SPME-GC-TOFMS) was used to identify volatile aroma compounds in raw rice (broken rice flour) and cooked rice (cooked rice， cooked rice with acid). The differences of volatile flavor compounds between samples were analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA) and aroma activity value(OAV). Results: A total of 98 volatile flavor substances were identified in broken rice flour， rice and rice with acid， which were 65，55 and 68 volatile substances， respectively， of which 31 were common substances. The number and content of substances were mainly alcohols， aldehydes， esters and ketones. Based on the content of volatile flavor compounds in the three samples， OPLS-DA analysis was carried out. The results showed that there were 54 different substances with VIP > 1 in the three samples. Among them， there were 24 substances such as 2-heptanone， 2，3-octanedione and dihydro-5-pentyl-2(3H)-Furanone in broken rice flour， 6 substances such as 3-thiophenecarboxaldehyde， 2，3-pentanedione and 2，6，6-trimethyl-2-cyclohexene-1，4-dione in rice， and furfuryl alcohol， furfural and thearone in rice with acid. Isovaleric acid and other 24 kinds. OAV analysis showed that ethyl caproate had higher OAV values in the three samples， and the OAV of 2-acetyl-1-pyrroline in broken rice flour and rice was > 10. The highest OAV value in acid-added rice was ethyl caproate， and 2-acetyl-1-pyrroline was not detected in acid-added rice. The OAV values of 1-octene-3-ol， nonanal， ethyl caproate and other substances increased to varying degrees compared with the substances with OAV > 0.1 in rice. These substances with OAV > 0.1 could assist the overall aroma presentation， which was one of the reasons for the difference in aroma between rice and rice with acid. Conclusion: HS-SPME-GC-TOFMS combined with OPLS-DA and OAV were used to explore the differences of volatile compounds between raw rice， cooked rice and cooked rice under acidic conditions， so as to provide data reference for clarifying the effect of nong-flavor liquor on the extraction of volatile flavor substances in rice during ‘mixed steaming and mixed burning’.

Abstract:To distinguish the differences in volatile species and components of six wild honeys in Yunnan， headspace-gas chromatography-ion mobility spectroscopy(HS-GC-IMS) was used to analyze the characteristic flavor components of jiangcheng wild big dagua honey， wild black honey， wild cliff honey， wild small dagua honey， wild tree cave honey and lancang wild big dagua Honey. The volatile flavor fingerprints of different varieties of honey were constructed by LAV software to compare the differences in the characteristic flavor substances of different varieties of wild honey in Yunnan province and to determine the main characteristic flavor compounds and their relative contents. The results showed that there were some differences in the flavor substances of the six kinds of bees. The difference between jiangcheng wild dagua honey and wild xiaogua honey was the largest， followed by the difference between wild black honey and wild tree hole honey， and the similarity between wild cliff honey， wild wild xiaogua honey， wild tree hole honey and lancang wild dagua honey was higher. A total of 80 volatile substances were detected and 65 were qualitatively detected， including 24 aldehydes， 22 alcohols， 6 ketones， 7 esters， 3 furans， 1 pyrazine， and 1 hydrocarbon ， 1 type of acids， 1 type of ethers. Twenty characteristic volatile markers (VIP>1) were screened by partial least squares-discriminant analysis， including 1-heptanol， 6-methyl-5-hepten-2-one， ethyl 2-methylpropionate， ethyl acetate， hexanal， cyclohexanone， linalool， butyraldehyde， dipropyl disulfide， citronellol， (E)-2-hexenal， oxidized linalool， 2-hexanol， 2-pentylfuran， 1-heptanol， (E)-2-heptenal， phenylacetaldehyde， benzyl alcohol， isobutanol， and 2-furanyl alcohol. Principal component analysis and cluster analysis showed that different varieties of honey were clearly distinguished， indicating that the HS-GC-IMS technique can be used to distinguish honey.

Abstract:In this study， the fatty acid composition and content in human milk of different cities and lactational periods were analyzed. A total of 204 human milk samples were collected from Baotou (n=41)， Beijing (n=40)， Jinan (n=20)， Kunming (n=33)， Shenzhen (n=21) and Xining (n=49)， including colostrum (n=28)， one month postpartum (n=67)， and four month postpartum (n=109). The content of fatty acids in human milk was analyzed by gas chromatography using C11 ∶ 0 as the internal standard. This study investigated the effects of lactational period and geographical location on fatty acids content of human milk in China. The results showed that the fat content in mature human milk was significantly higher than that in colostrum (P<0.05)， the fat content in Jinan human milk was the highest (~5 g/100 mL)， and the lowest were Kunming and Shenzhen (<3.0 g/100 mL). The content of C16 ∶ 0 during lactation was relatively stable at around 192 mg/g fat. The colostrum was rich in long-chain unsaturated fatty acids， and the content of C18 ∶ 2 n-6c and C18 ∶ 3 n-3 in colostrum was significantly lower than that in mature human milk (P<0.05). There were certain differences in the fatty acid content of human milk in different regions， and the ratio of linoleic acid/linolenic acid varies greatly. Further comparisons were made between the data in this paper and the fatty acid content of human milk in other countries. This study provided theoretical support for the quantitative analysis of human milk fatty acids as well as the influencing factors of human milk fatty acids concentration.

Abstract:In order to efficiently and rapidly detect Salmonella in milk， and improve the sensitivity of the anti-fouling biosensor. In this study， amphoteric poly (sulfobetaine methacrylate) (SBMA)-modified swab was used to obtain the anti-fouling property， and constructed a sensing platform with 'blue latex microspheres/adaptor' as the colorimetric signal probe for the rapid detection of Salmonella in milk samples. The linear detection of Salmonella was 103-107 CFU/mL， and the detection limit was 117.80 CFU/mL. The detection is completed in 20 min， which can be qualitative to the naked eye， can be combined with the detection of portable colorimeter smartphones， can be measured and read， and is easy to operate， which is also a rapid detection of Salmonella.

Abstract:In this work， chloramphenicol (CAP) as the research object， by optimizing the reaction conditions， an indirect competitive enzyme-linked immunosorbent assay(ic-ELISA) for CAP was constructed and applied to the detection of CAP residues in aquatic products. The optimal working conditions of the constructed ic-ELISA were 0.05 μg/well coating amount of CAP-OVA， coating conditions at 4 ℃ for 14 h， 0.5% nonfat milk powder as blocking solution， and the dilution ratio of CAP antibody was 1∶16 000. The results showed that the sensitivity(IC50) of the constructed ic-ELISA method was 4.88 μg/mL， and the detection limit (IC15) was 0.29 μg/mL. The cross-reaction rate of the chloramphenicol structural analogs and similar antibiotics were less than 0.1%. The spiked recovery experiments of 5.0， 10.0， 20.0 μg/kg in Larimichthys crocea， razor clam and bullfrog were carried out， and the recovery rates were within 83.90%-100.73%， and the intraday and interday coefficients of variation (CV) for this method ranged from 2.28% to 6.96%. The detection results were in good agreement with that of LC-MS/MS. The ic-ELISA of CAP in this study was simple to operate and has high sensitivity. It could be applied to the rapid quantitative detection of CAP residues in various aquatic products， and provide technical reference for ic-ELISA of other small molecule hazards. And it is also an indirect competitive enzyme-linked immunosorbent assay for the construction of the method provides technical reference.

Abstract:The purpose of this study was to provide new ideas for solving the problems of large leakage of template molecules and screening of functional monomers in the construction and application of molecularly imprinted polymers of citrinin. 1-hydroxy-2-naphthoic acid was used as a pseudo-template molecule， and a simultaneous determination of citrinin and 1-hydroxy-2-naphthoic acid was established based on liquid chromatography， which had a good recovery (≥ 95%) for molecularly imprinted eluent and could also separate citrinin from the alcohol extract of functional Hongqu. The functional monomer 2，6-diaminopyridine for the construction of molecularly imprinted polymer was optimized by the quantum chemical method through molecular configuration optimization， atomic charge distribution， and binding energy calculation. The preparation process of the imprinted polymer was optimized by response surface methodology. The adsorption capacity of the optimized polymer to citrinin was as high as (195.10 ± 13.21) ng/g， which was 0.79 times higher than that before optimization. Finally， the adsorption properties of the optimized polymer and the control polymer were compared with the polymer constructed with methacrylic acid as a functional monomer. The adsorption capacity of the former to citrinin was three times that of the latter， which confirmed the practicability of computer simulation in the construction of citrinin molecularly imprinted polymer. This study aimed to provide references for the construction of molecularly imprinted polymers and the enrichment and detection of citrinin.

Abstract:Objective: To ensure the risk level of hazardous substances in chili pepper， and analyze the unqualified situation of hazardous substances in chili pepper by combing spatial with temporal perspectives. Finally， by acquiring high-risk substances in chili pepper， and providing suggestions for efficient supervision of chili pepper safety. Methods: To evaluate the risk value of risk substances in chili pepper， the entropy method was used to calculate the risk level， and the 28 principles were used to classify and rank the risk level. In order to conduct spatiotemporal analysis of the risk substances in chili pepper， descriptive statistical methods were used for statistical description to conduct spatiotemporal analysis of the risks. Global and local autocorrelation analysis methods were used to analyze and explore the national spatial distribution patterns of high risk and high-risk substances in chili pepper. Results: Cadmium， lead， chromium， endosulfan， carbofuran and monocrotophos were high-risk substances in chili pepper； the overall change in the failure rate of chili pepper was stable from 2016—2020， and the failure rate of chili pepper in Hubei was the highest among the national provinces， and the failure of chili pepper in sampling places mainly occurs in supermarkets and farmers' markets. Conclusion: The classification results of chili pepper risk substances could improve the efficiency of government supervision， while providing a reference for enterprise self-regulation.

Abstract:Gut hormones are a large class of polypeptides and amines secreted by enteroendocrine cells (EECs)， which play an important role in appetite regulation， gastrointestinal motility， digestive enzyme secretion， and blood pressure and glycemic control. The secretion of gut hormones is regulated by dietary factors， and food-derived bioactive peptides (FBPs) are one of the important dietary factors regulating the secretion of gut hormones. This study reviewed the research progress and action mechanisms of FBPs regulating gut hormones secretion in recent years. In addition， the future research directions were prospected to provide reference for the research and application of FBPs in the regulation of gut hormones secretion.

Abstract:With the continuous development of nanotechnology， people inevitably come into contact with nanomaterials through various pathways. Titanium dioxide nanoparticles (TiO₂ NPs) as a typical representative of nano-metal oxide materials family， has been widely used as food additives in the food industry field due to their good whitening and anti-caking properties. Because of its small size and large specific surface area， could pass through the intestinal barrier， then enter the blood circulation and deposit in the organs in the end. Thereby affecting the physiological functions of cells in various parts， and causing metabolic disorders in the body， which makes people pay more and more attention to the adverse effects of TiO₂ NPs about the intestinal health and glucolipid metabolism of organisms. Therefore， this review summarized the effects of TiO₂ NPs on intestinal structure， digestion and absorption function and intestinal flora， and the effects of TiO₂ NPs on glucose and lipid metabolism and its molecular regulation mechanism were also discussed，which aimed to provide a reference for the treatment of intestinal diseases and disorders of glucolipid metabolism caused by food-borne TiO₂ NPs， as well as the regulation of the safe dosage of TiO₂ NPs.

Abstract:γ-Glutamyl transpeptidase(GGT) widely exists in a variety of organisms in nature， has transpeptidation and hydrolysis activities， and can synthesize γ-glutamyl amino acids/polypeptides according to different substrate conditions. Substances have attracted the attention of the food industry， pharmaceutical synthesis and other industries because they can be used as flavor enhancers or biological actives. There are abundant GGT resources in bacteria. In this paper， the structural characteristics， properties， catalytic reaction characteristics and related product characteristics of γ-glutamyl transpeptidase were reviewed in order to explore the potential of bacterial GGT and provided reference for future research prospects.

Abstract:Compared with animal-derived protein， plant protein is more healthy and easier to be digested and absorbed by the human body， thus gaining a large market demand. However， the low solubility and other functional properties of plant proteins limit their application in food. The increasing demand for proteins with better functional properties requires the application of physical processing techniques of different heat treatments and non-heat treatments to modify plant proteins. New physical processing technology can replace low energy efficiency and high intensity heat treatment in modification of plant proteins. In this paper， the mechanism and effect of new physical modification methods on the functional modification of plant proteins were reviewed in order to provide theoretical reference for enhancing the added value of plant proteins in subsequent industrial processing.

Abstract:Myofibrillar proteins are the most important proteins of muscle and their gelation properties have a decisive effect on the sensory quality of meat products. Due to the unique structural characteristics， plant polyphenols can interact with myofibrillar proteins during heat-induced gelation formation with the structural change and cross-linking of protein， which affects the gelation formation and gelation properties. In this article， the process and mechanism of the improvement of gelation formation of myofibrillar proteins based on plant polyphenols in the normal-ion strength system， low-ion strength system， and oxidative system were reviewed， aiming to provide a novel insight into the improvement of gelation properties of gel-type meat products based on environmental-friendly methods.

Abstract:Powder oil is a functional lipid food ingredient prepared by microcapsule technology， which can well protect core oil from the influence of the external environment. Compared with unembedded oil， it has the advantages of improving oxidation stability， extending shelf life， controlling release， and improving food quality. In this paper， the composition and preparation technology of powder oil， the influence on the physicochemical properties of microencapsulated powder oil and its application in food were systematically reviewed， and the review could provide the reference for the preparation of powder oil and its application in food industry.

Abstract:Metal elements play an important role in the formation and stability of wine quality and style. Recent studies have found that there are large differences in the content of metal elements in wine samples from different wine regions； different types and concentrations of metal elements have different effects on wine quality. In this work， the types， sources， contents and influencing factors of metal elements in wine were reviewed. The effect and its mechanism of metal elements in wine quality found in recent years were summarized， in order to provide references for wine brewing and quality control.

Abstract:Oral processing is not only a dietary process， but also a pleasure seeking process. The texture of food perceived by people is a multidimensional sensory characteristic. At present， rheology is no longer able to characterize this complex sensory perception. Tribology objectively characterizes the sensory properties of food in oral processing by simulating the processing process of food in the mouth and the lubrication behavior of food when pressed onto the surface of the mouth by the tongue. Oral tribology has become an important tool for characterizing the lubrication behavior in food oral processing. This article reviews the application of oral tribology in food processing and research and development， focusing on the sensory perception and lubrication mechanism of food in oral processing， such as astringency and lubrication， with the aim of providing reference for future food design.

Abstract:With the rapid development of economy and society， as well as the continuous improvement of science and technology， the living standards of the general public are increasingly improving， and the demand for nutrition and health is increasing. At this stage， food labeling is the mainly way to learn about nutritional information and characteristics of foods. However， due to the incomplete management system for food claims， non-standard claims often occur， which seriously affects the satisfaction and trust of the public towards food safety in China. This paper systematically arranged the requirements of Codex Alimentarius Commission and some countries and regions on food claim management， and compared and analyzed them with the current management system of food claims in China. Based on this， combined with national conditions， this paper put forward some suggestions on food claim management for government.

Abstract:With the development of the food industry entering a new stage， it is imperative to accelerate the construction of the new food standard system and comprehensively lead the high-quality development of the food industry. This study systematically combed and analyzed the food standard system and research in recent years， expounded the characteristics of food standard system in the future， and put forward suggestions， with a view to improving the government regulatory governance and system construction.