Abstract:Carbohydrates not only provide the main source of energy for humans， but also have important functions such as maintaining intestinal health， regulating blood sugar and cholesterol levels， promoting metabolism， and supporting the immune system. Therefore， exploring the precise structure-activity relationship of foodborne carbohydrates has become an important scientific problem. However， compared to genomics and proteomics， the inherent structural diversity and complexity of foodborne carbohydrates pose a major challenge to their study， which lags far behind that of proteins and lipid macromolecules. Based on this， this review focuses on the breakthrough of liquid chromatography and mass spectrometry (LC-MS)， ion mobility mass spectrometry (IM-MS) and low-temperature infrared spectroscopy in the analysis of foodborne sugar chains on the basis of classical sugar chain analysis methods， and further discusses the application of the latest computer processing methods and analysis techniques in the analysis of foodborne sugar chain. This review not only aims to gain a deeper understanding of strategies for foodborne carbohydrate analysis， but also looks at future trends leading to high-throughput， accurate foodborne sugar bioinformatics.

Abstract:Selecting pork loin， chicken breast and four different parts of beef (tenderloin， flank， eyeround and shoulder) as materials， the multi-level structural properties， texture characteristics， water distribution， nutrient composition and in vitro simulated digestion characteristics of meat were characterized， and the internal relationship between the multi-level structure， texture and digestion of meat was analyzed， aiming to provide a theoretical basis for establishing a quality evaluation system of plant-based meat analogues. The results show that meats had typically multi-hierarchical structures with muscle fibers， epicardium， sarcolemma and endocardium layered in a complex network structure at different scales. The tightness and thickness of meat fiber fascicle showed differences for these six types of meats. The morphological types of chicken fiber were the richest. The fiber bundle diameter of pork was the largest (75.21 μm)， followed by flank (57.09 μm)， eyeround (54.41 μm) and chicken (52.78 μm). The fiber bundle diameter of tenderloin was the smallest (33.58 μm). The muscle fibers of beef flank， shoulder and eyeround were observed arranged compactly， while chicken breast， pork loin and beef tenderloin were arranged loosely. The results of magnetic resonance imaging showed that the six kinds of animal meats three different water types， including protein-binding water， freezable water (myofibril inner water)， and free water (myofibril outer water). Water was evenly distributed in chicken and pork while unevenly distributed in four kinds of beef which contained more fat than others. Besides， the content and distribution of different water states affected the texture properties of meets. The microstructure of meat had a certain correlation with its texture and digestibility. The meat with closely arranged fiber bundles had higher hardness and chewability， and lower digestibility. The results in the current work provide scientific basis for the establishment of quality evaluation standards of plant-based meat analogue products.

Abstract:In order to optimize the preparation process of emulsion gels， a soy protein isolate- sugar beet pectin emulsion gel was prepared by duo induction of laccase and Ca2+/Mg2+， and a model for the comprehensive property index of the emulsion gel textural properties was established based on the normalization method. High concentration of Ca2+ was replaced with lower concentration of Mg2+ to reduce the amount of ions added during the emulsion gel preparation. The results showed that compared with the laccase and Ca2+ duo-induced emulsion gel， the laccase and Mg2+ duo-induced emulsion gel had shorter gelation time (340 s)， similar rheological properties， more uniform microstructure and oil droplet distribution， better storage stability and higher release rate in the small intestine (73.1% for β-carotene， 85.7% for riboflavin). This study not only prepared a novel emulsion gel that can be used as the multi-phased nutrient carrier， but also offered a possible solution of replacing high concentrations of Ca2+ with lower concentrations of Mg2+.

Abstract:In order to improve the stability and bioavailability of tea polyphenols(TP)， this paper was to prepare the embedding system of tea polyphenols， which use carrageenan or instant agar compounded with whey protein as wall materials. The embedding rate of tea polyphenol was selected as the main optimization index to investigate the embedding effect of carrageenan or instant agar compounded with whey protein on tea polyphenols. The results showed the highest embedding rate of (91.94±0.31)% when the carrageenan-whey protein embedding system prepared at pH 2， core-to-wall ratio of 1∶20 and wall mass fraction of 6%. While the instant agar-whey protein embedding system had the maximum embedding rate of (98.48±0.39)% when prepared at pH 4， core-to-wall ratio of 1∶25 and wall mass fraction of 4%. The results of the antioxidant activity measurements suggested that both carrageenan and instant agar complex systems with good antioxidant properties， where the DPPH radical scavenging rate of the carrageenan and instant agar systems was as high as (49.55±0.00)% and (48.35±0.52)%， respectively， and the highest ABTS radical scavenging rates of (90.90± 0.23)% and (81.35±0.90)%. Both the carrageenan-whey protein embedding system and the instant agar-whey protein embedding system can effectively protect the tea polyphenols， especially for instant agar system can improve the storage stability of tea polyphenols. Our findings can help the design and development of seaweed hydrocolloids as embedding wall for bioactive ingredient.

Abstract:To investigate the modification effect of ferulic acid (FA) synergistic toughening treatment on potato starch (PS)， the gelatinization and gel properties of modified potato starch were studied by means of electronic scanning electron microscope， rheometer and Fourier transform infrared spectrometer. The results showed that under the condition of ferulic acid synergistic toughening， the particle size of FA-PS composite system increased， and when FA was 1%， the average particle size reached the maximum value of (41.52±0.01) μm. The whiteness increased， and the peak value was (97.10±0.01). The peak viscosity， disintegration value and retrogradation value of FA-PS decreased. The viscoelasticity of FA-PS gel was improved， and the loss tangent (tanδ) was the lowest when the content of FA was 3%. The toughening treatment made the gel structure of potato starch compact， and the addition of ferulic acid made the gel pore become uniform， which affected the short-range ordered structure of the composite system. Toughening treatment promoted the interaction between potato starch and ferulic acid in the composite system， and could effectively improve the gelatinization and rheological properties of potato starch.

Abstract:Lentinan is the main active substances in Lentinus edodes， but its structure is complex and the activity mechanism is not clear， so the application of lentinan is limited. Therefore， deepening the discussion of the structure-activity relationship of lentinan is helpful to fully explore the medicinal value of lentinan， and it is of great significance for the research and development of new products. Lentinus edodes crude polysaccharide was prepared by water extraction and alcohol precipitation method， and Lentinus edodes polysaccharide was deproteinized by Sevage method. EDTA-2Na was used to remove metal ions from lentina edodes. Congo red test， Fourier infrared spectroscopy， atomic force microscopy， DPPH， ABTS， hydroxyl radical scavenging experiments and antibacterial experiments were used to compare the changes of the structure， antioxidant and antibacterial activities of lentina edodes before and after metal ions removal. The results showed that after metal ions were removed， the rigidity of the triple helix structure of lentinus was weakened， and the chain thickness decreased from 1.2 mm to 0.8 mm. The scavenging ability of Lentinan on ABTS and hydroxyl free radicals decreased， while the scavenging ability of DPPH free radicals increased. When the concentration of polysaccharide was 1 mg/mL， the scavenging rates of DPPH， ABTS and hydroxylradical were 94.94%， 83.52% and 26.52%， respectively. The bacteriostatic test showed that the bacteriostatic effect of lentinan was decreased by removing metal ions. When the concentration of polysaccharide was 40 mg/mL， the range of inhibition zone against E. coli and Staphylococcus aureus decreased from 9.50 mm to 8.30 mm and 12.25 mm to 11.33 mm， respectively. Metal ions， as the main components of lentinan， participate in its structural composition and play an important role in its activity.

Abstract:Lactic acid bacteria play an essential role in fermentation due to their characteristics and secretion of various metabolites. In this study， two lactic acid bacteria with high β-glucosidase activities were screened from kimchi and identified as Lactobacillus plantarum PC7-C6 and PC7-C11). The probiotic characteristics of the two strains and the enzymatic characteristics of PC7-C11which has higher enzyme production ability， were analyzed. The results showed that the two strains were γ-hemolysis， sensitive to ampicillin and clarithromycin， moderately sensitive to tetracycline， erythromycin， and clindamycin， and could grew at pH 4. The auto-aggregation rate of the two isolates ranged from 50% to 64%， and the co-aggregation rates with Escherichia coli were more than 60% after co-incubating for 8 hours. The hydrophobicity of the isolates towards ethyl acetate was 70.41% and 61.19%， and the hydrophobicity of the isolates towards xylene and n-hexane was between 30% and 40%. The two isolates could inhibit the growth Escherichia coli， Hafnia alvei， Staphylococcus saprophyticus， Serratia marcescens， and Staphylococcus equorum. The antioxidant capacity of PC7-C11 was superior to that of PC7-C6， with a 59.33% scavenging rate of 1，1-diphenyl-2-picrylhydrazyl(DPPH)and 53.49% scavenging rate of hydroxyl radicals respectively. The enzymatic characteristics of PC7-C11 showed that the optimal reaction temperature and pH for enzyme activity were 40 ℃ and pH 7. Ethanol， glucose， dimethyl sulfoxide， SDS， EDTA， Fe2+， Mg2+， Na+， and Ca2+ inhibited enzyme activity to varying degrees， while K+ has a certain promoting effect on enzyme activity.

Abstract:To improve the bioavailability of buckwheat protein， buckwheat antioxidant peptides (BAPs) was isolated from the fermentation hydrolysate of buckwheat by using Sephadex G-25 and reversed phase-high performance liquid chromatography (RP-HPLC)， and its structure and composition were preliminarily analyzed. The H2O₂-induced RAW 264.7 macrophages cell model of oxidative stress was further established to evaluate the antioxidant activity of BAPs. The results showed that the BAPs obtained after separation by RP-HPLC has a purity of 96.25% and a molecular weight of 5.8 ku. Vitamin C equivalent antioxidant capacity (VCEAC) was used to indicate that DPPH·， ABTS+·， ·OH scavenging ability and reducing power of BAPs were (12.12±0.27)， (153.82±5.04)， (901.95±39.30)， (109.23±1.18) μg/mg， respectively. In the RAW 264.7 macrophage oxidative stress model， BAPs with the concentration of 200 μg/mL had a significant (P<0.05) effect on all measured antioxidant indicators compared with the model group， which significantly (P＜0.05) promoted the viability of oxidatively damaged cells by 13.80%， reduced the levels of intracellular reactive oxygen species (ROS) by 40.63% and malondialdehyde (MDA) by 11.92 nmol/mg prog. Meanwhile， the activities of superoxide dismutase(SOD) and catalase (CAT) were increased by 23.48 and 15.71 U/mg prot at this concentration， respectively. The above results showed that BAPs can effectively inhibit the oxidative stress response of RAW 264.7 macrophages， which could provide a theoretical basis for the development of buckwheat peptides as natural antioxidants.

Abstract:The present study was conducted to unravel the molecular mechanism underlying the synergistic effect of capsaicin and quercetin on the regulation of glucose metabolism in small intestine. The Caco-2 monolayer model was established to investigate the effect of capsaicin and quercetin， both singly and combined， on the cell viability and cell membrane permeability. Additionally， western blotting was utilized to determine the expression levels of Occludin， cytoplasmic protein ZO-1， epidermal growth factor receptor (EGFR) and fibrillar muscle protein F-actin as well as key proteins involved in glucose transport including GLUT2， SGLT1 and Na+/K+-ATPase. Results showed that the cell viability of all treatment groups was higher than 75%， demonstrating no toxic effect of capsaicin and quercetin on Caco-2 cells. Administration of capsaicin and quercetin increased the TEER values of Caco-2 monolayer model (315.70±26.65) Ω·cm2， which indicated smaller permeability and thus stronger barrier function. Furthermore， compared to the CK group， capsaicin and quercetin treatments upregulated the expression levels of Occludin (>0.65)， ZO-1 (>0.51)， EGFR (>0.19)， and F-actin (>0.04)， but downregulated that of GLUT2 (>1.00)， SGLT1 (>0.78) and Na+/K+-ATPase (>0.87). In summary， capsaicin and quercetin can exert a synergistic effect on the regulation of glucose metabolism in small intestine and high dose levels of capsaicin and quercetin at a ratio of 1∶3 was found to be optimal. The potential molecular mechanism can be attributed to the enhancement of barrier function of small intestine and downregulation of key proteins involved in glucose transport， which consequently hinders glucose absorption to achieve a hypoglycemic effect.

Abstract:In order to improve the utilization rate of blueberry resources and reduce the environmental harm of its processing by-products. The effects of ultra-high pressure extraction， ultrasonic extraction， and solvent extraction on the composition and content of polyphenol (BRP) in blueberry residue were investigated by high performance liquid chromatography (HPLC-MS/MS). Activated HSC-T6 cells were used as models to detect the effects of BRP on the survival rate and cytotoxicity of HSC-T6 cells by thiazole blue and lactate dehydrogenase methods. The autophagy induction effect of BRP on HSC-T6 cells was observed by transmission electron microscopy and acridine orange staining. The expression level of autophagy related proteins in HSC-T6 cells was detected by Western blot. The degree of fibrosis in HSC-T6 cells was analyzed by enzyme-linked immunoassay (ELISA). The results showed that there were 14 components in BRP， and cyanidin-3-O-glucoside accounts for the highest proportion among the three extraction methods， which are 57.530%， 58.703% and 54.830% respectively. The BRP components obtained by the three extraction methods were the same， but the content was different. The BRP content of ultra-high pressure extraction method was significantly higher than that of conventional solvent method and ultrasound-assisted extraction method (P < 0.05). BRP significantly inhibited the proliferation of HSC-T6 cells (P < 0.05)， and showed a time-dose effect relationship within a certain concentration range. Autophagy was induced by up-regulating the expression of Beclin-1 and LC3-II， and down-regulating the expression of p62. And， BRP significantly decreased the secretion levels of COL-Ⅰ， COL-Ⅲ and TNF-β1 in HSC-T6 cells (P < 0.05). In conclusion， the total content of BRP components extracted by ultrahigh pressure extraction is the highest and the biological activity is the strongest， and BRP could induce autophagy by inhibiting the proliferation of activated HSC-T6 cells， thus exerting its anti-fibrosis effect.

Abstract:Objective: To investigated the protective effects of pachymic acid on okadaic acid(OA)-induced neurotoxicity in PC12 cells and identified a potential mechanism. Methods: Pachymic acid (10， 15， 20 μg/mL) was used as protective drugs to protect PC12 cells injured by OA (40 nmol/L). Cell viability， LDH released， intracellular Ca2+ concentration and caspase-3 activity were detected. The levels of bax and p-taus202 were detected by western blotting. Results: Compared with the control group， PC12 cells treated with 40 nmol/L OA was significantly decreased the viability to (64±3.6)% (P＜0.01)， increased the release of LDH to (141.3±3.1)% increased intracellular Ca2+ concentration to (123.5±5.2)% and caspase-3 activity to (257.0±22.8)% (P＜0.01)； compared with the model group， 50 μg/mL pachymic acid significantly increased cell viability to (90.5±3.3)% (P＜0.01)， decreased LDH released to (117.5±3.8)%， decreased [Ca2+]i， to (123.5±5.2)% and reduced caspase-3 activity to(120.0±4.1)% (P＜0.01). Western blot results confirmed that OA increased the protein expression of bax and p-taus202， pachymic acid down-regulated the expression of bax and p-taus202. Conclusion: the protective effect of pachymic acid against OA-induced apoptosis in PC12 cells was related to the inhibition of tau hyperphosphorylation.

Abstract:Objective: To investigate the activity of oligopeptide components in Soy Sauce-Type Baijiu (JOPs) to alleviate the inflammatory damage of gastric mucosal epithelial cells caused by Helicobacter pylori (Hp) infection and its molecular mechanism. Methods: The JOPs were isolated and amino acid sequence identified. The cell model of human gastric mucosal epithelial cells (GES-1) under Hp-exposure was established. CCK8 assay method was used to detect the cell viability， and ELISA method was applied to evaluate the inflammatory epithelial cytokines levels. Western blotting was applied to detect the protein expression in NF-κB signal pathway. Results: The JOP-1 (Phe-Trp-His-Gly) performed the most protective activity against the Hp-induced GES-1 cell viability decline. JOP-1 significantly inhibited Hp-induced inflammatory epithelial cytokines (TNF-α， IL-1β， IL-6， PGE2 and NO) over-release. At the same time， JOP-1 inhibited the Hp-induced NF-κB signal pathway activation， and attenuated the Hp-induced COX-2 and iNOS proteins over-expression. Conclusion: The oligopeptides in Soy Sauce-Type Baijiu can alleviate the Helicobacter pylori induced inflammatory damages on gastric mucosal epithelial cells by regulating NF-κB signaling pathway and the COX-2， iNOS protein expression. Furthermore， the Hp-exposure induced inflammatory epithelial cytokines over-secretion was also inhibited.

Abstract:To investigate the impact of probiotics combined with yeast extract on the body composition and gut microbiome of female soccer players during routine training， a 42-day randomized， double-blind， placebo-controlled trial was conducted with 42 athletes. Body composition data and fecal samples were collected on days 0， 21， and 42 for metagenomic analysis. The results indicated significant increases in muscle mass in the lower left leg and upper right arm segments by 6.99% and 6.92% respectively at day 21， and a 5.48% increase in trunk bone mass， while the waist-to-hip ratio decreased by 4.13% at day 42 in the intervention group compared to the control group. Analysis of the gut microbiome revealed changes in microbial composition and function， characterized by increased abundance of beneficial bacteria such as Bifidobacterium animalis and Streptococcus salivarius， and decreased presence of potentially harmful bacteria like Haemophilus parainfluenzae and Roseburia faecis， along with reductions in phosphoglycerate mutase antibodies， prolyl-tRNA synthetase， and large subunit ribosomal proteins. Correlation analysis indicated that the combined supplement of probiotics and yeast extract enhanced trunk bone mass and reduced waist-to-hip ratios by modulating the abundance of Bifidobacterium animalis， increased upper right arm muscle mass through Streptococcus salivarius， and further reduced waist-to-hip ratios through the downregulation of small subunit ribosomal protein S13. These findings reveal the potential mechanisms by which probiotics and yeast extract regulate the stability of the gut microbiome to promote health in female soccer players and provide evidence-based support for the development of personalized microecological preparations.

Abstract:Food allergy(FA) is an abnormal response of the human immune system to a specific food that causes discomfort in several systems， including the digestive， respiratory， skin and cardiovascular systems. In this study， heat-killed Lactobacillus paracasei JY56 (HK-L. paracasei JY56) with strong anti-allergic activity was screened from 20 strains of lactic acid bacteria by hyaluronidase inhibition assay and RBL-2H3 cell assay. Subsequently， the safety of L. paracasei JY56 was evaluated by whole genome sequencing and in vitro safety assays. Finally， an ovalbumin (OVA)-induced FA mouse model was constructed to further clarify the effect of HK-L. paracasei JY56 on the alleviation of clinical symptoms in FA mice. The results showed that HK-L. paracasei JY56 had high β-aminohexosidase (β-HEX) inhibition rate， and the levels of cytokines IL-4， IL-5， IL-13 and TNF-α were significantly reduced after its intervention. Whole genome sequencing analysis revealed that L. paracasei JY56 does not possess the ability to virulently and transmitly receive antibiotic resistance genes. The safety evaluation experiments such as antibiotic susceptibility test， hemolysis test and harmful metabolite evaluation revealed that L. paracasei JY56 was susceptible to commonly used antibiotics and did not produce hemolysis or harmful metabolites. OVA stimulation resulted in decreased body weight and rectal temperature and increased allergy score in mice， while HK-L. paracasei JY56 intervention significantly alleviated allergy symptoms in mice. In conclusion， this study provides a theoretical basis for the use of HK-L. paracasei JY56 for the alleviation of food allergy and related diseases.

Abstract:Lard and corn oil were used to explore the difference of obesity in BALB/c mice caused by oil and fat. And the effects of Lactobacillus rhamnosus ATCC 53103 (LGG) on prevention of obesity and regulation of mice intestinal flora were analyzed. A total of 50 5-week-old BALB/c male mice were randomly divided into 5 groups included control check (CT)， high-lard fed group (S)， high-corn oil fed group (P)， high-lard fed + LGG gavage group (SL) and high-corn oil fed + LGG gavage group(PL). The experiment lasted for 8 weeks and the related indexes were detected. The results showed that obesity was much easier to be caused by excessive lard compared with excessive corn oil. The body weight (41.42±2.30) g， body mass index (BMI， 4.24 kg/m2±0.26 kg/m2)， Lee's index (351.44±9.06)， fat coefficient (118.87±3.91) mg/g， total triglyceride (TG， 0.81 mmol/L±0.08 mmol/L)， low density lipoprotein cholesterol (LDL-C， 0.29 mmol/L±0.01 mmol/L)， alanine aminotransferase (ALT， 53.42 U/L±0.95 U/L) and aspartate aminotransferase (AST， 164.65 U/L±9.35 U/L) were all significantly higher in mice in group S than in group P while only the liver index was higher in mice in group P(51.07±1.35) mg/g than in group S (47.32 mg/g±1.93 mg/g， P<0.05). Amongst the changed intestinal flora in mice， the relative abundance of Bacteroidetes (8.69±4.68)% and CF231 (0.31±0.19)% decreased while Allobaculum (2.19±1.47)% increased in group S. And the F/B ratio was higher in group S (9.15±1.19) than that in group P (4.25±0.57， P<0.05). Comparatively， only the relative abundance of Streptococcus was slightly higher in mice in group P (14.41±6.37)% than in group S (4.91±2.23)%. However， LGG intervention was more effective in preventing obesity and regulating intestinal flora disorder in mice caused by lard. The body weight and fat coefficient of mice were lower in group SL (34.53 g±1.53 g， 26.10 mg/g±2.51 mg/g) compared with in group PL (37.69 g±2.41 g， 65.88 mg/g±1.98 mg/g， P<0.05). And the up-regulation of Bacteroides was more obviously in group SL. The down-regulation of Firmicutes was observed， but the regulation of Deferribacteres could not be conducted by LGG in group PL (P>0.05). In conclusion， obesity was more likely to be caused by lard than by corn oil. But LGG was more effectively in preventing obesity and regulating intestinal flora disorder caused by lard.

Abstract:Pomegranate is a medicinal food， and a large amount of pomegranate peel and other by-products are produced during processing. In order to improve the utilization of pomegranate by-products， the active ingredients of pomegranate peel were extracted by different methods and their antioxidant activities were investigated in this paper. Subsequently， these bioactives were steadily encapsulated by water-in-oil-in-water emulsion (W/O/W) emulsion and the effect of W/O/W on the stability and bioavailability of polyphenols was investigated. The results showed that the ultrasound-assisted alcoholic extraction obtained higher yield of polyphenols with 25% than the ultra-high pressure extraction and enzymatic assisted extraction. The DPPH， hydroxyl radical scavenging and total reducing power of bioactives extracted from pomegranate peel was better than VC. While the ABTS+ scavenging activity of the bioactives was not significantly different from that of VC. And its scavenging activity of superoxide anion was higher than that of VC when its concentration was lower than 0.4 mg/mL. W/O/W emulsion could improve the storage stability of the bioactive extracted from pomegranate peel， and protect the active substances in gastric digestion to targeted delivery and release in the simulated small intestine. This study provides theoretical reference for the further processing of pomegranate peel by-products.

Abstract:Due to the low yield of bacteriocin in lactic acid (LAB) bacteria fermentation， optimizing fermentation conditions of bacteriocin-producing by LAB is the most direct way. Antibiotic resistance tests， hemolysis tests and and whole genome sequence analysis showed that Lactiplantibacillus plantarum NMGL2 isolated from Inner Mongolian cheese did not carry high virulence factors and had no significant virulence effects and had no risk of metastasis of resistance genes， demonstrating the safety of L. plantarum NMGL2 in phenotype and genotype. Then， the fermentation conditions of bacteriocin produced production by L. plantarum NMGL2 were optimized， with Staphylococcus aureus as the indicator bacteria and the diameter of the antimicrobial ring as the investigation target. First， a single-factor test including inoculation rate， initial fermentation pH， culture temperature and liquid medium volume on bacteriocin production was performed. Based on the results of single-factor test， three significant factors including inoculation rate， initial fermentation pH and culture temperature were optimized by the response surface of the three-factor three-level design of the Box-Behnken method. The optimal fermentation conditions for bacteriocin production by L. plantarum NMGL2 were determined and the results showed that the optimal fermentation conditions were initial fermentation pH 7.0， inoculation rate of 1.3%， culture temperature of 37 ℃. The verification test results showed that the inhibition zone diameter of the indicator bacteria (Staphylococcus aureus) was 13.8 mm under the optimized fermentation conditions， which was basically consistent with the predicted value of the model (13.4 mm)， and the fitting rate reached 96.64%， indicating that the model was reliable and effective. This study provide a technical foundation for he production of bacteriocin by Lactobacillus plantarum NMGL2 and its application.

Abstract:In order to study the interaction between the dominant bacterial community of Koumiss and the relationship between the bacterial community and characteristic flavor， this experiment conducted mono- or co-cultures fermentation of 4 strains of lactic acid bacteria (LAB) and 2 strains of yeast isolated from traditional Koumiss， and measured the acidity， pH， changes in the amount of LAB and yeast in 14 groups of fermentation group. HS-SPME-GC-MS was used to study the differences of volatile flavor compounds in different fermentation groups. Lotka-Volterra model and partial least square regression (PLSR) were used to analyze the interaction coefficient between LAB and yeast and the correlation between dominant bacteria and the formation of characteristic flavor compounds in Koumiss. Lactobacillus casei (L. casei) had the fastest acid production rate among LAB， with pH value of 3.89 in the late stage of fermentation. For yeast， pH value of Kluyveromyces marxianus (K. marxianus) dropped to 4.16. The acid production of co-culture fermentation group was better than that of mono-culture fermentation group. The fermentation of LAB and Kazachstania unispora (K. unispora) can promote the growth of K. unispora. After 72 h of mixed fermentation with K. unispora， the bacterial colonies of Lactobacillus plantarum (L. plantarum) and Lactobacillus paracasei (L. paracasei) reached 1.91 × 106 CFU/mL and 1.66 × 106 CFU/mL， respectively. Also， it promoted the production of caprylic acid and n-decanoic acid. While the mixed fermentation of LAB and K. marxianus can form competitive inhibition. Also， the production of ethyl octanoate and ethyl caprate was inhibited in the co-fermentation system. The inhibitory effect on L. casei and Lactobacillus paracasei (L. paracasei)， which produce acid rate faster， was stronger than the L. helveticus and L. plantaru).

Abstract:In order to improve the properties of fish skin gelatin， different proportions of tannins， rutin and their oxidation states (0%， 0.5%， 1%， 2%， 4%) were added to investigate their impacts on the properties， color， water distribution， protein structure， and protein banding of puffer (Takifugu rubripes) skin gelatin. The results showed that the addition of tannin， oxidized tannin and rutin significantly increased the gelatin strength， gelling and melting temperature of the skin gelatin (P<0.05)， while the effect of oxidized rutin was not obvious. Tannin and oxidized tannin demonstrate no significant effect on the gelatin color， while rutin and oxidized rutin have a significant effect， especially oxidized rutin， which results in a significant decrease in the L value (6.07%-8.26%) of the gelatin， improvement of a value (88.89%-93.88%) and b value (85.94%-91.67%). Low-field nuclear magnetic resonance results showed that the addition of two polyphenols and their oxidation states shortened the T2 relaxation time and promoted the combination of gelatin and water molecules. Cold field electron microscopy showed that addition of tannin， rutin and their oxidation states is beneficial to the formation of a dense gel network structure. SDS-PAGE results indicated that there was no obvious change in the protein bands of gelatin， and the covalent cross-linking between polyphenols and gelatin molecules was not significant， and they mainly interacted through non-covalent interactions. The infrared spectrum shows that both the amide-A band and the amide-I band shift to blue， indicating that the number of hydrogen bonds formed increases. Overall， tannin， rutin and their oxidation states may be combined with gelatin molecules through non-covalent interactions (especially hydrogen bonds)， thereby improving the gel properties of puffer skin gelatin. These findings contribute certain evidences for property improvement of puffer skin gelatin.

Abstract:In order to utilize the hairtail resources effectively and prepare high-quality angiotensin-converting enzyme (ACE) inhibitory peptide， the most suitable protease for the preparation of hairtail ACE inhibitory peptide was screened using ACE inhibition rate and hydrolysis degree as evaluation indexes. The enzymatic process conditions were optimized by single factor and response surface. The optimized hairtail ACE inhibitory peptide was analyzed for molecular weight and amino acid composition. The ACE inhibitory peptide was further purified by ultrafiltration and Prep-HPLC， and the active fraction with the highest ACE inhibition rate was obtained. The results showed that the protemax was the best protease for the preparing ACE inhibitory peptide， and the optimized process parameters were obtained as follows: enzymatic hydrolysis time of 3 h， hydrolysis temperature of 45 °C， enzyme dosage 5 000 U/g and pH 7.0. Under this condition， the theoretical ACE inhibition rate was 80.15%， the actual value was 80.43%， and the IC50 was 0.33 mg/mL. The relative molecular weight of the ACE inhibitory peptide was mainly distributed below 1 000 u. The amino acid composition pattern of the hairtail ACE inhibitory peptide was reasonable， with high content of fresh and hydrophobic amino acids. The six fractions were separated by ultrafiltration and Prep-HPLC， and the highest activity was obtained for fraction 5 with an IC50 of 0.11 mg/mL. This study provides a theoretical basis for the application of hairtail in functional foods for hypertension.

Abstract:In order to prepare seal oil Pickering emulsion and study its stability， different stabilizers (sodium caseinate， lecithin and β-cyclodextrin)， different oil volume fractions (40%， 50%， 60%， 70%， and 80%)， and different stabilizer dosages (1， 2， 3， 4， 5 g/100 mL) on the characteristics of the emulsion (viscosity， standing emulsification index， centrifugal stability and particle size) were studied and the preparation process of seal oil Pickering emulsion were preliminarily determined. Then， the pasteurization stability (65 ℃/30 min， 72 ℃/15 s)， freeze-thaw stability (freezing at -18 ℃ for 24 h， thawing at 25 ℃) and storage stability (25 ℃/28 d) were evaluated by the appearance and microscopic changes， particle size and centrifugation stability of the emulsion. The results showed that under the conditions of β-cyclodextrin as stabilizer， the oil volume fractions was 70%， and the amount of stabilizer was 4 g/100 mL， seal oil Pickering emulsion could be prepared， and the particle size and centrifugal stability of the emulsion were 15.31 μm and 86.73%， respectively. The effect of pasteurization treatment on the characteristics of the emulsion was not obvious， and the effect of treatment at 72 ℃/15 s on the characteristics of the emulsion was less than 65 ℃/30 min. The freeze-thaw treatment significantly affected the emulsion， and after freeze-thaw， the emulsion was unstable， the oil phase and water phase was separated， and the characteristics of the emulsion were no longer present. Within 28 days of storage at 25 ℃， although the particle size of the emulsion increased and the centrifugation stability decreased， the basic characteristics of the emulsion were maintained. In short， seal oil Pickering emulsion could be prepared by β-cyclodextrin， which has good thermal stability and storage stability (within 28 days)， but freeze-thaw stability.

Abstract:Using shark cartilage as raw material， the optimal enzymatic preparation process of collagen was optimized through single factor and response surface experiments， and the structure and stability of the prepared collagen were analyzed. The results showed that the optimal conditions of extraction collagen were as follows: 9 150 U/g of pepsin， 39.85 hours of extraction time， pH 1.67， and a ratio of 1∶15(g/mL). Under these conditions， the extraction rate of collagen was (85.09±0.17)%， and the prepared collagen retained a relatively complete triple helix structure， which conforms to the characteristics of type II collagen. The stability study showed that the denaturation temperature of the prepared collagen was 39.9 ℃， and its viscosity decreased significantly with the increase of temperature and salt concentration， but there was no linear relationship between the viscosity and pH value， and its viscosity was the smallest at pH 7 (4.26 mPa·s). Circular dichroism analysis further indicated that with the increase of salt concentration and temperature， the triple helix structure of collagen changed， when the temperature exceed the denaturation temperature of 39.9 ℃， the tripartite helix structure gradually unrotated and denatured. This study provides a specific theoretical basis for the high-value utilization of shark resources.

Abstract:Objective: to study the effects of different heating temperatures and times on the structural characteristics， enzymatic hydrolysis characteristic， and the content of glutamine at non-nitrogen terminal of wheat gluten. Methods: Firstly， wheat gluten were pretreated with heating treatment at three heating temperatures (60， 70， 80， 90 ℃) for (15， 30， 60 min) and then enzymatically hydrolyzed by Alcalase 2.4L alkaline protease. Using the untreated wheat gluten hydrolysate as a reference， we compared the structure changes of wheat gluten and the hydrolysis efficiency and content of glutamine at non-nitrogen terminal of hydrolysates. Results: the dough structure formed by wheat gluten proteins in water gradually loosened or even dispersed with heating treatment at increasing heating temperature， and at the same time heat treatment changed the secondary structure of wheat gluten， which might expose more enzymatic cleavage sites. Moreover， heat treatment significantly increased the extent of hydrolysis and increased the content of glutamine at non-nitrogen terminal (P<0.05). In particular， compared to wheat gluten without heating treatment， the control protease lysates wheat gluten with heating treatment at 90 ℃ for 30 min showed better performance， the content of the components with a molecular weight less than 1 ku of whose hydrolysates increased from 75.85% to 80.75% and the content of glutamine at non-nitrogen terminal of whose hydrolysates increased from 26.27% to 34.87%. Conclusions: heat treatment was beneficial in hydrolysis and increasing the content of glutamine at non-nitrogen terminal of wheat gluten hydrolysates.

Abstract:The application of curcumin in the food industry is limited due to its poor water dispersibility and instability. To overcome this limitation， in this study， a pH-driven method was used to construct soybean isolate protein-curcumin nanoparticles (SPI-Cur) using soybean isolate protein as the packaging material (SPI)， and the loading rate was used as the evaluation index， and the three major factors affecting the loading rate of soybean isolate protein-curcumin nanoparticles (protein concentration， curcumin addition concentration， and pH-driven combinations) were respectively subjected to one-factor experimental analysis and response surface condition optimization， the optimal preparation process for SPI-Cur nanoparticles was determined to be: protein amount concentration of 50 mg/mL， curcumin addition mass concentration of 0.4 mg/mL， and pH-driven combination of pH value adjusted back from 13.0 to 7.0. By the optimal process obtained SPI-Cur nanoparticles were evaluated in terms of the particle size， ζ-potential， PDI dispersibility index， appearance and morphology， Fourier infrared spectroscopy (FTIR) and x-ray diffraction， it was concluded that curcumin was successfully loaded into the SPI nanocomplexes and was captured in an amorphous form in the soybean isolate protein matrix. In addition， the stability analysis results concluded that SPI could effectively improve the thermal and gastrointestinal stability of curcumin， and had a better protective effect on curcumin. This study provides an optimal process for the preparation of SPI-Cur nanoparticles by pH-driven method and also shows that SPI can be used as a delivery matrix for hydrophobic bioactives.

Abstract:In order to explore the effects of ultrasonication and germination synergistic treatment on the structure and physicochemical properties of brown rice starch， spectroscopic analysis and electron microscopy were employed to compare the changes in α-amylase activity， starch morphology， crystalline structure， and physicochemical properties across four groups: untreated brown rice， ultrasonication and germination synergistic treatment brown rice， germinated brown rice， and ultrasound-assisted germinated brown rice. The results showed that ultrasonication and germination synergistic treatment increased the α-amylase activity and reducing sugar content in germinated brown rice by 0.9 times and 12.0 times， respectively； while decreased the starch content by 16.2% compared with brown rice. The synergistic role of ultrasonication and germination contributed to more pits and pores in the surface of brown rice starch granules， but still maintained the original morphological characteristics. The treatment did not significantly change the crystal form of brown rice starch， but remarkably decreased the relative crystallinity (P<0.05). Ultrasonication and germination synergistic treatment had a significant effect on the gelatinization viscosity of brown rice starch， where the gelatinization enthalpy value was increased by 0.6 times， and the breakdown viscosity was reduced by 22.4%. In conclusion， synergistic treatment of ultrasonication and germination significantly enhanced the α-amylase activity， and further affected the structural characteristics and physicochemical properties of brown rice starch. These findings suggest that ultrasonication and germination synergistic treatment enhances α-amylase activity in brown rice， subsequently altering starch structural characteristics and physicochemical properties， thereby providing a theoretical foundation for the improvement of brown rice starch products and the development of germinated whole grain foods.

Abstract:In order to study the effects of very fast chilling on the myofibrillar proteins properties of chilled pork after slaughter， this study analyzed the effects of different very fast chilling treatments (very fast chilling -I group: chilling rate of 9.31 ℃/h； very fast chilling -II group: chilling rate of 14.43 ℃/h) on the myofibrillar proteins of the pork M. longissimus thoracis et lumborum muscles at 1， 2-5， 6， 12， 24 and 72 h after slaughter. The changes of myofibrillar proteins hydration (solubility and hydrophobicity)， gel properties (water-holding capacity gel)， oxidation properties (sulfhydryl content and carbonyl content)， myofibrillar miniaturization index and myofibrillar proteins degradation. The results showed that the hydrophobicity of myofibrillar proteins surface tended to increase， and the solubility， water-holding capacity gel， sulfhydryl content， carbonyl content and myofibrillar fragmentation index tended to decrease in the pork M. longissimus thoracis et lumborum muscles under different chilling treatments after slaughter. The amount of myogenic fibrin bound to bromophenol blue， gel water retention and carbonyl content were significantly lower in the very fast chilling -Ⅰ and very fast chilling -Ⅱ groups than in the control group (P<0.05)， while the very fast chilling -Ⅱ group was significantly lower than the very fast chilling -Ⅰ group (P<0.05)， and myogenic fibrin solubility and sulfhydryl content were significantly higher in the very fast chilling -Ⅱ group than in the control and very fast chilling -Ⅰ groups (P<0.05). In conclusion， the very fast chilling treatment group could improve the functional properties of chilled pork myofibrillar proteins and effectively inhibit protein oxidation， in which very fast chilling with a chilling rate of 14.43 ℃/h was the best chilling method. The results of the study aimed to provide a theoretical basis and data support for the application of very fast chilling technology in the industry.

Abstract:Objective: To explore the effect of slightly acidic electrolyzed water on the sensory quality of fruits and vegetables and preliminarily explore its mechanism. Methods: Selecting cucumber as the research object， using a physical property analyzer to determine its texture indicators， using solid phase microextraction combined with GC-MS to compare and analyze its flavor substances， further explore the composition and structural changes of its epidermal wax， using GC-MS technology to qualitatively and quantitatively analyze its epidermal wax components， and using scanning electron microscopy to observe its microstructure. Results: Treatment with slightly acidic electrolytic water for 20 minutes significantly increased the skin hardness， flesh hardness， and crispness of cucumber， decreased its skin thickness， and its flavor substances were not affected. The total content of epidermal wax decreased significantly， with a trend of decreasing alkane content and increasing terpene content. The microstructure of epidermal wax became smoother and smoother. Conclusion: Slightly acidic electrolytic water can improve the sensory quality of cucumber by decomposing the wax in the outer epidermis， exposing the cuticle， and exchanging external substances through the pores of the epidermis， thereby increasing its moisture content， significantly improving its hardness and fracturability.

Abstract:In order to explore the effects of different enzymatic hydrolysis methods on flavor substances of Lentinus edodes， two single enzyme (cellulase， flavor protease) and one complex enzyme (cellulase+flavor protease) were selected for enzymatic hydrolysis of Lentinus edodes and the differences in the flavor substances of of Lentinus edodes after different enzymatic treatments were compared. The results showed that: Compared with the control group， the total amount of soluble sugar in cellulase group， flavor protease group and compound enzyme group increased by 144.21%， 114.24% and 438.28%， respectively， and the total amount of organic acid increased by 9.06%， 8.31% and 13.77%， respectively (P<0.05). The compound enzyme treatment group was significantly higher than the single enzyme treatment group. The content of taste-inducing nucleotides in the compound enzyme group was significantly higher than that in the control group， cellulase group and flavor protease group (6.55%， 4.90% and 5.75%， respectively， P<0.05). Compared with the control group， the free amino acid content of flavor protease and compound enzyme treatment groups increased by 56.19% and 58.95%， respectively (P<0.05). A total of 62 volatile flavor compounds were detected by gas chromatography-mass spectrometry， among which alcohols and sulfur compounds were the most abundant. The relative contents of 1-ocene-3-ol (mushroom alcohol) and 1，2，3，5，6-pentathiocycloheptane (lentinan) in the complex protease treatment group were higher， which reached 68.27% and 8.06%， respectively. The results indicated that the complex enzymatic hydrolysis of cellulase and flavor protease could promote the release of flavor substances including soluble sugar， organic acids， flavor nucleotides， free amino acids， 1-octen-3-ol and 1，2，3，5，6-pentathioheterocyclicheptane (lentinan) in Lentinus edodes.

Abstract:In order to improve the antioxidant activity and flavor of snow pear juice， pear juice was fermented with Lactobacillus casei Y5-2b， Lactobacillus plantarum C17 and Lactobacillus acidophilus CH-2， respectively. Physicochemical properties and antioxidant activities were characterized. And high-performance liquid chromatography and gas chromatography-ion mobility spectrometry (GC-IMS) was applied to analyze the nutrients and aroma components. Results showed that the three strains had good growth and metabolism in pear juice. Moreover， the proliferation metabolism of Y5-2b and C17 showed better performance， with a stable number of viable bacteria reaching 9.0 lg CFU/mL at 20 hours. The antioxidant activity of fermented pear juice increased significantly(P<0.05). The sugar content decreased， with glucose being the most consumed and the utilization rate ranging from 5.29% to 8.85%. Partial organic acid content showed a decrease， with no malic acid detected in groups Y5-2b and C17. There was no significant difference in malic acid content between the CH-2 group and the unfermented group (118 mg/100 mL)， and the citric acid content decreased by 33.65%， 42.97%， and 38.71% respectively after fermentation. Different lactic acid bacteria fermentation had different effects on the content of phenols in pear juice， mainly arbutin， catechin and rutin. A total of 44 aroma components were identified from juice samples， of which 3-hydroxy-2-butanone， n-butyraldehyde， butyric acid and other characteristic flavor substances with fruit aroma increased in varying degrees after fermentation. In conclusion， lactic acid bacteria endowed the pear juice with abundant substances， flavor and high antioxidant activity， which provides a certain theoretical basis for lactic acid bacteria fermentation of pear juice.

Abstract:Fermented kiwifruit extract is rich in vitamins， enzymes， minerals， secondary metabolites and other nutrients， which belongs to the new type of food with potential health effects. In this study， 6 kinds of lactic acid bacteria and 2 kinds of yeast were inoculated into kiwifruit juice for fermentation to detect the changes of ingredients in the process of probiotic fermentation of fruit juice. The bioactive substances in the fermentation process of each group were detected and analyzed by using spectroscopy and chromatography technology. The results showed that the lactic acid bacteria and yeast strains in the experiment played an important role in the microbial counts， physicochemical properties， and biological activity of the fermented kiwifruit extract. The microbial counts， of lactic acid bacteria and yeast bacteria reached the peak value on the 5th day， which ranged (7.89-9.30) lg(CFU/mL) and (7.05-8.18) lg(CFU/mL)， respectively. The number of Bacillus rhamnosus LG0262 reached 9.30 lg(CFU/mL). After fermentation， the acidity of the lactic acid bacteria fermentation group was higher than that of the yeast fermentation group. The pH of the lactic acid bacteria fermentation group is between 3.25-3.45， and that of the yeast fermentation group was between 3.51-3.70. The soluble solid content and ethanol concentration ranged (10.3-30.6)。Brix and (13.549-50.82) mg/mL， respectively and there was a positive correlation between the two indicators (R2 = 0.963， P<0.01). The types and concentrations of GABA， polysaccharides and organic acids increased fermentation. At the 60th day of fermentation， the polysaccharide content in the fermented kiwifruit extract prepared by Lactobacillus helveticus LG4316， Lactococcus lactis LG0827， and Lactiplantibacillus plantarum LG1034 reached 0.30%， 0.30%， and 0.29%， respectively. The concentration of lactate， tartaric acid and succinic acid in the fermented kiwifruit extract prepared by Lactiplantibacillus plantarum LG1034， Bacillus rhamnosus LG0262， and Saccharomyces cerevisiae J2861 was the highest， reaching 2 482.03， 1 842.18 μg/mL and 168.78 μg/mL， respectively.

Abstract:Defatted rice bran was used as medium materials. By comparing the effects of microbial species， fermentation time， fermentation temperature and inoculation amount on the content of free phenolics in rice bran， the solid state fermentation conditions of rice bran were optimized. The contents of free and bound phenolics and flavonoids in rice bran before and after fermentation were determined， as well as the compositions and contents of individual phenolics and their antioxidant activity were also analyzed. Result: The Rhizopus oryzae strain had the strongest fermentation ability of increasing the content of free phenolics to a maximum of 612.29 mg GAE/100 g dw in rice bran. The optimum solid state fermentation conditions of rice bran with Rhizopus oryzae were as follows: the fermentation time was 5 days， the fermentation temperature was 30 ℃， and the inoculation amount was 1%. Under this condition， the contents of free phenolics and flavonoids in fermented rice bran were 162.2% and 58.4% higher than those in unfermented rice bran， respectively， but there was no significant difference in the contents of bound phenolics and flavonoids in rice bran before and after fermentation. Compared with the unfermented rice bran， the contents of free and bound phenolics changed significantly； Among them， the content of gallic acid had the most increased by 2.44 times and 8.11 times， respectively； The ABTS， FRAP， and ORAC antioxidant capacities of free phenolic in rice bran were significantly increased by 100.7%， 71.3%， and 67.0%， respectively. Conclusion: Solid-state fermentation of rice bran with Rhizopus oryzae could significantly improve the release of bound phenolic， increase the content of total phenolics， and enhance the total antioxidant activity.

Abstract:To investigate the impact of multi-strain koji production on the process and quality of Zhejiang Rose Vinegar， a study was conducted to optimize the multi-strain ratio using an orthogonal experiment. The two best-performing mixed strains were applied to the production of rose vinegar， and a quality evaluation was performed. The results indicated that two ratios with the highest amylase and protease activities were 1 ∶ 1 ∶ 1 ∶ 1 and 1 ∶ 1 ∶ 1 ∶ 2 of Monascus purpureus ∶ Aspergillus oryzae ∶ A. niger ∶ Rhizopus， which were prepared and subsequently applied to the vinegar brewing process. Fermentation tracking showed that the multi-strain fermentation process for rose vinegar was successfully completed， with the total acidity of the final products reaching 6.97 g/100 mL and 6.63 g/100 mL， respectively， representing a yield increase of 17.21% and 11.29% compared to the traditional method. Eight flavor-contributing organic acids， including acetic acid， lactic acid， malic acid， and citric acid， were detected in the two rose vinegar samples， with non-volatile acid contents of 56.04 mg/L and 57.85 mg/L， respectively， which were comparable to the 41.053 mg/L of traditional rose vinegar. A total of 44 volatile flavor compounds were identified using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS)， with volatile flavor compound contents of 6 348.14 mg/L and 6 791.75 mg/L in the two groups， slightly higher than the 5 030.07 mg/L in traditional vinegar. Sensory evaluation revealed that rose vinegar brewed with multi-strain koji showed slight improvements in sweetness and ester aroma， with the 1 ∶ 1 ∶ 1 ∶ 2 multi-strain group achieving the highest sensory scores. This study provides a reference for the mechanized improvement of koji production in traditional rose vinegar manufacturing.

Abstract:In order to study the quality changes during the boiling process of green chilli sauce and to construct a relevant colour protection model， three colour protection agents， namely disodium hydrogen phosphate(A)， zinc gluconate (B) and sodium D-isoascorbate (C)， were selected for the colour protection test， taking chlorophyll preservation rate， a value， colour difference value(△E) within 15 d and sensory score as the indicators of consideration， with the resulting composite score as the evaluation index. The results of the one-way experiment showed that the optimum additions of the three colour protectors were A (0.3%)， B (0.075%) and C (0.07%). Response surface method was used to investigate the effect of three colour protectant formulations on the colour of green chilli paste using the composite score as the response value. The results showed that the effects of the three colour protectors on the colour and lustre of green chilli paste were different and ranked as A>C>B. The quadratic polynomial regression equation model of the factors affecting the colour of green chilli sauce was constructed as follows: YComposite Score = +0.85+0.080A+0.030B-0.048C+0.063AB+0.072AC-0.012BC-0.12A2-0.020B2-0.15C2， with a coefficient of determination of R2 of 0.9825， indicating that the experimental data and the model test correlation is good and can be used to determine the optimum colour protection formulation for green chilli paste， i.e. 0.30% addition of disodium hydrogen phosphate， 0.09% addition of zinc gluconate and 0.07% addition of sodium D-isoascorbate. The green chilli paste made with this formulation was bright green and glossy in colour， with an a value of -4.33， an organoleptic score of 94.35 and a composite score of 0.91. The chlorophyll preservation rate of the green chilli paste was 72.62%， which was 30.19% higher than that of the unprotected treatment (only 55.78%)， and the effect of colour preservation was significantly better than that of the traditional process. The colour protection model constructed in this study can accurately reflect the effect of selected colour protectors on the colour quality of green chilli sauce， determine the optimal colour protection process， and solve the problem of chlorophyll browning in green chilli sauce.

Abstract:Peach pulp mixed with k-carrageenan was applied to form the recombinant preserved peach (RPP) by hot air drying， in which erythritol was selected as the co-solute. The effect of erythritol addition (0%， 1%， 5%， 9%) on the quality characteristics of RPP was investigated. Based on the drying experiment， with the increase in erythritol concentration， the water mobility was significantly decreased as well as the drying rate. Color analysis illustrated that with increasing erythritol addition， the L value (brightness) of RPP was significantly increased， while the value of a (redness and greenness) was decreased. The electronic nose sensors W1C， W3C， and W5C had larger response values. When subjected with erythritol， the response values of the sensors were increased. Additionally， PCA analysis revealed the significant difference in the flavor between the control group and the RPP groups. Texture analysis suggested that the highest hardness， chewiness and gumminess were observed in RPP with 9% erythritol， which were 30.51 N， 7.21 N， and 14.42 N， respectively. However， the cohesiveness was significantly reduced compared to the control group. Meanwhile， no statistical significance was achieved in elasticity between control group and RPP groups. As erythritol increasing， the shrinkage of RPP was significantly decreased. Compared with the control group， the 1%， 5%， and 9% treatment groups decreased by 4.00%， 12.25%， and 17.75%， respectively. The low field nuclear magnetic resonance results showed that the water mobility was evidently altered by the erythritol. The proportions of the moisture with low flowability in RPP with 5% erythritol and 9% erythritol were increased. Raman spectroscopy was applied to evaluated the changes in chemical group under the different treatment， in which the vibration peak near 2 918 cm-1 gradually became sharp. These results suggested the formation of dense structure through the hydrogen bonding， which reflected the excellent texture properties at the macro-level.

Abstract:To investigate the quality deterioration of mushrooms (Agaricus bisporus) and the law of their reactive oxygen metabolism during cold chain circulation. In this experiment， the sensory quality， main physiological indicators and reactive oxygen metabolism of A. bisporus fruiting bodies were dynamically measured during post-harvest pre-cooling， cold chain transportation and simulated low temperature shelf life， and the correlation between quality deterioration and physiological indicators and reactive oxygen metabolism was investigated by Pearson correlation analysis software. The results showed that the quality of A. bisporus did not change much during the period of pre-cooling and cold chain transportation during cold chain circulation， while gradual quality deterioration occurred during storage in simulated supermarket low temperature shelf life (12 ℃±1 ℃). The respiratory peak appeared at the 3rd day， and after the respiratory peak， its sensory quality decreased rapidly， mainly manifested as wilting， browning， opening， and texture softening， etc. At the same time， the physiological indexes also changed significantly， as shown by the decrease of soluble solid content (SSC)， total antioxidant capacity (T-AOC)， and the dynamic increase in relative conductivity (RC)， the contents of total phenol (TP)， malondialdehyde(MDA)， O₂·-， and H2O₂， and the activities of enzymes related to active oxygen (ROS) metabolism. Pearson correlation analysis revealed that postharvest browning of mushrooms was significantly correlated with changes in polyphenol oxidase (PPO) activity， total phenol content， and malondialdehyde content， and browning was influenced by changes in PPO， peroxidase (POD)， and superoxide dismutase activities (SOD) and phenolic content. The highest correlation was found between browning and PPO(R2=0.95)； there was a strong correlation between weight loss (WL) and changes in malondialdehyde content (R2=0.90). The ROS contents accumulated with the extension of storage time， although the activities of PPO showed an increasing trend， but the total antioxidant capacity of the antioxidant enzyme system was decreasing， which led to the accelerated deterioration of storage quality. According to these laws， the shelf life of A. bisporus can be predicted more accurately and provide some theoretical guidance for mushroom post-harvest cold chain circulation and quality monitoring during shelf sales.

Abstract:Objective: The quality changes caused by microorganisms in the process of pickle storage and circulation were investigated and a new method to prolong the storage life of pickle was developed. Methods: The growth rate of 8 lactobacillus from pickles was tested under different pH media and their gas production was measured. Before cabbage fermentation， adding pickled liquid， Lactobacillus acidophilus， Lactobacillus plantarum， xylitol， etc.， The pickle was fermented and stored at ambient and low temperatures for 31 d and 73 d respectively. The color of pickle was scored， and acidity and turbidity and volatile substances were determined. Result: Lactobacillus plantarum was the dominant bacterium， followed by Lactobacillus brevis when 8 lactobacillus grow on pH 4.5 culture medium. Lactobacillus acidophilus is the dominant bacterium， followed by Lactobacillus plantarum of 8 lactobacillus on pH 4.0 to 3.0 culture medium. Lactobacillus brevis， Leuconostoc pseudoentericus， and Lactobacillus fermentans all contributed to gas production during pH 4.0 to 3.0， and gas production mainly caused by Lactobacillus brevis during pH 4.0 to 4.5， caused by Lactobacillus malefermentans at pH 3.5， while gas production was greatly inhibited at pH 3.0. The addition of 2 mL/L 1×105 CFU/mL Lactobacillus plantarum combined with 20 mg/g xylitol significantly prolonged the storage and shelf life of the pickles at ambient and low temperature. Conclusion: The treatment with 1×105 CFU/mL Lactobacillus plantarum combined with 20 mg/g xylitol significantly inhibited the accumulation of total volatiles， allyl isothiocyanate， and naphthalene in pickles， which contributed to the maintenance of the original odor characteristics.

Abstract:Taking bluefin tuna as the research object， the effects of different concentrations of chlorogenic acid (200 mg/kg sample， 400 mg/kg sample) on tuna meat color， protein and fat oxidation， freshness， water distribution， muscle microstructure and other quality characteristics during low-temperature storage were investigated. Based on this， the effects of chlorogenic acid on myoglobin structure and microenvironment were further explored through Raman spectroscopy and fluorescence spectroscopy. The results showed that adding chlorogenic acid effectively delayed the browning of bluefin tuna meat， inhibit protein oxidation and fat oxidation， and maintain the freshness of the sample. Compared with the treatment group， the muscle fiber bundles of the control group samples contracted and the gaps became larger， resulting in varying degrees of breakage. Overall， the effect of low concentration of chlorogenic acid is better than that of high concentration treatment group. The multispectral results showed that chlorogenic acid had a fluorescence quenching effect on myoglobin； and the decrease of α-helix ratio was 39.2% and 28.0% in the control and CA treated groups， respectively， indicating that chlorogenic acid can effectively stabilize the secondary structure of myoglobin.

Abstract:Objective: Astragalus， yellow and cassia bark have good antibacterial activity and can be used as safe and efficient natural preservatives after blending. This study aimed to explore the application effect of the compound extract on pork preservative. Methods: The experiment evaluated the effect of antibacterial and antioxidant activity， combining the evaluation of total colonies， TVBN value， pH value and sensory index， and tested the corrosion ability of the compound of spices. At the same time， the 16S rRNA sequencing technology analyzed the microbial composition and diversity changes of the adding group and the control group in the storage process of fresh pork， and comprehensively showed the correlation between the microbial abundance changes of the adding system and the pork preservation (storage time). Results: Compound natural preservative can prolong the shelf storage period of fresh pork by 5-6 days. Based on 16 SrRNA gene sequencing analysis， 21 genera were identified. Pseudomonas， Acinetobacter and Myroides were the main microorganisms causing spoilage. It is found that the changes in the main metabolic pathway of natural storage fresh pork are consistent with the changes of the dominant microorganism Kurthia， Myroides and Pseudomonas. During the 5 days storage period of cold pork with compound natural preservatives， the proportion of the main spoilage genus Acinetobacter.decreased from 20.08% to 1.64%， Pseudomonas from 21.10% to 7.13%， Kurthia increased by 0.7%， and Myroides decreased from 13.02% to 7.94%. Conclusion: The research has proved the superiority of natural compound preservative as pork preservative， and laid a foundation for making full use of traditional spices to develop food preservative.

Abstract:Volatile compounds of Strong-aroma liquors of three vintages (2011， 2014 and 2015) were analyzed by using headspace solid phase microextraction combined with gas chromatography/mass spectrometry and multivariate statistical analysis methods in this study. A total of 75 volatile compounds were identified in Strong-aroma liquors of three vintages， including 40 esters， 10 alcohols， 5 aldehydes， 3 ketones， 5 aromatics， 8 terpenes and 2 furans. Relative odour activity value (ROAV) method was used to identify 17 key flavor compounds and compounds that had modification effect on overall flavor. In combination with orthogonal partial least squares discriminant analysis， Spearman correlation and random forest model， 14 compounds were screened as differential compounds for vintage. Furthermore， 22 compounds were selected as differential compounds for true and false， and used as biomarkers， and then fingerprint reference chromatography of Strong-aroma liquors of three vintages were established using these biomarkers respectively. The similarity between the reference chromatography and the true sample chromatography of each vintage was above 0.9， and the similarity between the reference chromatography and the adulterated sample chromatography was below 0.9. The results obtained showed that the established reference chromatography is strong enough to differentiate adulterated wines and is reliable in quality control for Strong-aroma liquors.

Abstract:Objective: Pseudomonas fluorescens is a dominant spoilage bacterium in refrigerated Marine fish. Its strong ability of extracellular protein secretion is one of the important factors leading to fish spoilage. Thus， extracellular protein composition and secretion pathway under the whole genome level of P. fluorescens from fish are explored. Methods: A variety of bioinformatics analysis software was used to predict the extracellular protein secretion of P. fluorescens PF08 from fish and to analyze its function. Results: In the 5 514 proteins encoded by P. fluorescens PF08 in the whole genome， sixty-six classical secreted proteins with Sec/SPI type signal peptides， localized extracellular， with none or only one transmembrane structure and no GPI anchor site were screened. Most proteins were 101-400 amino acids， small molecular proteins， and the proportion of hydrophobic amino acids was the highest. 13 pili proteins， 11 enzymes， 2 flagellins， 7 DUFs family proteins， 17 unknown functional hypothesized proteins and 16 other functional proteins were annotated by Nr database. Further through COG analysis， these proteins were mainly annotated into the functional categories of intracellular transport， secretion and vesicle transport， cell motility， signal transduction and cell wall， membrane and biological envelope. GO annotation showed that these proteins were highly annotated in the three categories of biological processes， cell components and molecular functions. Conclusion: The secretory proteome of P. fluorescens consisted of different functional and properties proteins， involving key proteins that promote the extracellular colonization， biofilm formation， decomposition of food components， etc. It provides an important basis for further research on the spoilage mechanisms of P. fluorescens in fish.

Abstract:Hydraulic pressing (HP)， spiral pressing (SP)， subcritical butane extraction (SBE)， and supercritical CO₂ extraction(SCE) were used to extract oil from tiger nuts. The effects of four oil extraction methods on the oil yield， physicochemical indicators， and lipid concomitant content of tiger nut oil were systematically compared. The volatile components of the four types of oil were analyzed by headspace solid-phase microextraction gas chromatography-mass spectrometry. The results showed that different oil extraction methods significantly impacted tiger nut oil's oil yield and basic physicochemical indicators (P<0.05). SBE had the highest oil yield (31.89%)， and the lowest acid value (0.44 mg/g)， peroxide value (0.03×10-1g/100 g)， and water content (0.06 g/100 g) were detected in SCE， SP， and SP oil samples， respectively； The color of tiger nut oil extracted by SCE and SBE were clearer and more transparent. The content of unsaturated fatty acid in SCE oil was 49.63 mg/g， which was significantly increased by 3.50%-5.54% (P<0.05) compared with the other three methods. There were significant differences (P<0.05) in the content of lipid concomitant and oxidative stability among four tiger nut oil samples (P<0.05). The content of tocopherols (26.85 mg/100 g) and total phenols (16.65 mg GAE/100 g) in SP oil was the highest， the content of total sterols (283.48 mg/100 g) in SCE oil was the highest， and the content of phospholipids (1.05 mg/g) in SBE oil was the highest. SP oil exhibits strong oxidative stability， the oxidation induction period was 34.40 hours， which was 1.24 times， 8.27 times， and 6.70 times that of SBE oil， HP oil， and SCE oil， respectively. A total of 162 volatile compounds were detected in the four oil samples， mainly including heterocyclic compounds， acids， aldehydes， alcohols， ketones， esters， and hydrocarbons. The relative content of heterocyclic compounds in SP oil was the highest at 44.86%， and the relative content of aldehydes in HP oil and SBE oil was the highest at 50.18% and 26.03%， respectively， the maximum relative content of benzene compounds in SCE oil was 60.00%. According to OAV， key flavor compounds were identified for four oil samples， including 16 for SP oil， 23 for HP oil， 8 for SCE oil， and 22 for SBE oil. Among them， hexanal was the common component； PCA found differences in the characteristic flavors of four oil samples. The research results can provide a theoretical reference for the development of tiger nut oil products.

Abstract:In order to study the effect of free amino acids on flavor compounds of yak meat during baking and their correlation， sensory description and gas chromatography-ion mobility spectrometry (GC-IMS) were used， automatic amino acid analyzer detects free amino acids， odor activity value (OAV) and taste activity value (TAV) were used to determine the relationship between the concentration of key compounds and the taste threshold value of free amino acids， and the changes and effects of key compounds were analyzed by orthogonal partial least squares discrimination analysis (OPLS-DA) and principal component analysis (PCA)， respectively， using multiple least squares statistics. The results showed that 95 compounds were identified by GC-IMS， including 17 aldehydes， 14 alcohols， 18 esters， 17 ketones， 2 acids， 13 heterocyclic compounds and 14 alkenes. The most influential compounds were ketones (21.01%-28.57%)， which could make yak meat present milk flavor and fruit flavor， followed by heterocyclic compounds(15.26%-22.55%)， which could make yak meat present nut， mushroom and roast flavor. A total of 17 kinds of free amino acids were detected， among which Glu， Ala and Trp were the most prominent， which made yak meat taste sweet. Arg was the key flavor amino acid of yak meat. PCA analysis showed that yak-C and D had the best flavor and yak-B， E and F were similar. The results provide a reference for distinguishing the flavor characteristics of yak meat and the flavor mechanism of amino acids.

Abstract:Neurodegenerative diseases have a great negative impact on people's health and life. With the increase of the aging degree of the world population， its incidence rate is rising year by year. There are a variety of plant natural products， which have various biological activities， such as antioxidant， anti-inflammatory， regulating autophagy， etc.， and are characterized by wide sources and high safety. With the further research on the extraction method， composition， structure and functional activity of natural products in plants， it has been found that many of them， such as flavonoids， polysaccharides and peptides， can improve many neurodegenerative diseases such as cerebral ischemia， stroke， Alzheimer's disease， spinocerebellar atrophy and so on by alleviating oxidative stress， regulating cytokine levels， regulating autophagic flow， and inhibiting excitatory toxicity. Studies in cells and animals have shown significant neuroprotective effects， which can be used as a potential neuroprotective agent to prevent and relieve nervous system diseases. Due to the low bioavailability and poor permeability of the blood-brain barrier， most plant natural products cannot effectively penetrate the blood-brain barrier to target specific areas to achieve therapeutic concentration of the disease， so it is necessary to use exosomes， nanoparticles and other carriers to deliver them to the diseased areas of the brain to play a role. The neuroprotection mechanism and targeted delivery system of plant natural products in food were discussed in order to provide help for the further research and application of plant natural products.

Abstract:Cereals are important food crops in China. As the main nutritional component of cereals， starch is closely related to the quality of starch-based foods. However， natural starch has shortcomings such as easy aging and poor shear resistance， and the gelatinized starch also has problems such as water separation， easy aging， and thermal instability， limiting its application range. Introducing hydrophilic colloids such as non-starch polysaccharides is a green and environmentally friendly starch modification method. Moreover， the hydrolysates of polysaccharides also exhibit potential applications to improve the processing characteristics of starch， which is of great significance for food processing. This article summarizes the effects and mechanisms of polysaccharides on starch gelatinization， rheology， texture， and in vitro digestion properties， as well as the research progress in the effects of polysaccharide hydrolysates on the quality of cereal starch. It is expected that this work could provide theoretical reference for improving the physical properties of cereal starch-based foods.

Abstract:With the improvement of people's living standards and the change of consumption structure， the pursuit of healthy and safe diet has become a mainstream. At the same time， public demand for meat in China increased year by year which brought a large amount of greenhouse gas emissions and created a serious burden on the environment. In addition to providing sufficient nutrition， plant-based products can also reduce the burden on the environment， and can reduce the carrying of pathogens compared with animal-derived foods. Edible mushrooms as raw materials for plant-based meat production research is an emerging and popular direction that not only brings enough protein but also provides other nutritional values to meet people's demand for health and meat nutrition. This review introduced some development status of artificial meat， which mainly described the shelf life， flavor improvement and characteristics analysis as an alternative component of plant-based meat were mainly expounded， and the progress related to edible mushrooms as raw materials for plant-based meat production， aiming to provide references for industry research producers.