Abstract:Dietary fiber plays a potential role in regulating energy intake and stabilizing postprandial blood glucose. As an important physical property of soluble dietary fiber， viscosity is also a key contributor to its nutritional effect. Nowadays， the nutritional effect of dietary fiber based on its physical properties has attracted researchers' attention， and viscosity's regulating effect on appetite has become an important entry point for the study of physical nutrition. The present article summarizes the health-promoting effects of dietary fiber's main physical and chemical properties， while the intervention effect and mechanism of dietary fiber viscosity-mediated appetite during eating was discussed systematically. The paper is believed to provide some ideas for the development and application of satiety-enhancing foods. Also， it is expected to lay a certain theoretical foundation for further in-depth and systematic exploration that reveals the health-promoting effects of dietary fiber.

Abstract:In order to explore the changes of main active substances in Lactobacillus rhamnosus fermentation of Ganoderma lucidum fruitum powder and its inhibitory effect on hepatoma cell HepG2， a solid fermentation method was used to prepare the fermented Ganoderma lucidum fruitum powder with Lactobacillus rhamnosus as fermentation strain and Ganoderma lucidum fruitum powder as fermentation substrate， and its main active ingredients and antioxidant capacity were studied. Plant metabolomics of Ganoderma lucidum fruitum powder was determined and its surface structure was observed by scanning electron microscopy. The inhibitory effect of Ganoderma lucidum alcohol extract on hepatocellular carcinoma cells was detected by CCK-8 method. The effect of Ganoderma lucidum alcohol extract on hepatocellular carcinoma cell migration was detected by cell scratch method. Hoechst 33258 detected the effect of Ganoderma lucidum alcohol extract on cell nucleus and verified the apoptosis effect. The expression of apoptosis-related genes in HepG2 cells was analyzed by PCR. The results showed that the contents of triterpenoids and polysaccharides were 4.075 mg/g， 2.347 g/100g and 4.604 mg/g respectively compared with those before fermentation. The antioxidant capacity of Lactobacillus rhamnosus fermented Ganoderma lucidum powder was significantly improved compared with the original Ganoderma lucidum powder and fermented control Ganoderma lucidum powder. The results of plant metabolomics showed that the material composition and peak area of the three samples were significantly different. Cell test results showed that the ability of fermented Ganoderma lucidum alcohol extract to inhibit HepG2 cell growth and block cell migration was significantly increased， and the apoptosis was more significant in Hoechst 33258 results. PCR test confirmed that the intervention of fermented Ganoderma lucidum alcohol extract significantly up-regulated the apoptosis-related genes Bax， Cyclin-A， CDK-2， P21 and P53， and significantly down-regulated the apoptosis-related genes Bcl-2. Conclusions: Lactobacillus rhamnosus fermentation of Ganoderma lucidum can increase the contents of main active substances， such as triterpenoids， polysaccharides and flavonoids of Ganoderma lucidum， and the ethanol extract of Ganoderma lucidum fermentation has stronger inhibitory effect on HepG2 cells.

Abstract:Natural bioactive peptides often have poor functional properties and thermal stability， in order to improve the antioxidant ability and thermal stability of chicken lung peptides， plastein reaction involving pepsin and exogenous amino acids was used to treat peptides from chicken lung. High performance liquid chromatography (HPLC) was applied to compare the molecular weight changes before and after the reaction， while the properties of the substances were characterized by UV spectra， fluorescence spectrum， X-ray diffraction spectrum， scanning electron micrographs (SEM). Meanwhile， Fourier transform infrared spectrum (FTIR) and circular dichroism (CD) spectrum were employed to explore the changes of the secondary structure of peptide and plastein. The results showed: Firstly， the DPPHo free radical scavenging rate， chelating ability of Fe2+ and ·OH scavenging rate increased by 51.85%， 31.11% and 31.30% while the thermal denaturation temperature raised from 122.06 ℃ to 136.15 ℃ after 3% Cysteine supplementation. Secondly， the molecular weight and surface hydrophobicity increased， UV and fluorescence spectra showed that the changes of amino acid microenvironment improved the antioxidant activity. Thirdly， the X-ray diffraction pattern revealed that the main diffraction peak widened but the intensity decreased after the reaction， the SEM results displayed that the process involved hydrolysis and repolymerization of molecules. Finally， the results of FTIR and CD showed that the peptide molecules were stretched and the hydrophobic groups were exposed， which might be the reason for the improved antioxidant capacity of the peptides. In summary， plastein reactions changed the secondary and tertiary structures of proteins， thus effectively improving the antioxidant capacity and thermal stability of bioactive peptides.

Abstract:Objective: A peptide with antioxidant activity was screened from whey protein hydrolysate and used to protect Probio-M8 during the freeze-drying process. The whey proteins were hydrolyzed by alkaline protease and separated by ultrafiltration and three different molecular weight peptide samples were obtained， k1 (>8 ku)， k2 (3-8 ku)， and k3 (<3 ku). The peptides were then purified and identified by strong cation exchange chromatography， reversed-phase high-performance liquid chromatography (RP-HPLC)， and liquid chromatography-mass spectrometry (LC-MS). 1，1-Diphenyl-2-trinitrophenylhydrazine (DPPH) scavenging， resistance to superoxide anion radicals， and absorption of oxidative radicals were used as assays to assess antioxidant activity and were screened. Results: Samples 3-2 and 4-6 showed high antioxidant activity. Five and six antioxidant peptide sequences were identified for samples 3-2 and 4-6， respectively. Sample 3-2 was able to protect B. lactis Probio-M8 in vacuum freeze-drying， increasing the survival rate of the strain to (88.31±0.02)% and also reducing intracellular reactive oxygen species levels and protecting cellular enzyme activity. Conclusion: Sample 3-2 was effective in reducing cell damage caused by the vacuum freeze-drying process of B. lactis Probio-M8.

Abstract:In this study， the non-covalent complexation between EC and apoRBF， and the effects on the structural and functional properties of proteins were investigated using a combination of fluorescence， circular dichroism (CD) spectra， transmission electron microscopy (TEM)， dynamic light scattering (DLS). The fluorescence results showed that EC did not change the characteristic emission peak of apoRBF at 330 nm， and the fluorescence intensity of apoRBF decreased with an increase in EC concentration， suggesting EC interacts with apoRBF， causing changes in the tertiary/quaternary structure of the protein， while having no effect on its primary and secondary structure. The fluorescence fitting results showed the binding constant K and the number of binding sites n between EC and apoRBF were 3.65×104 mol/L and 98.5， respectively. After dialysis at 4 ℃ and 40 ℃ for 12 h， the release rates of EC in FEC were 29.1% and 45.9%， respectively， which were lower than those of free EC， indicating that ECs bond to apoRBF， and lower temperature was more conducive to the binding of EC molecules and proteins. After incubation with simulated gastrointestinal fluid for 2 hours， the release rates of EC in FEC were 68.6% and 32.2%， respectively. Compared with the release rate of free EC， it showed a relatively slow and sustained release process， indicating the binding of EC to apoRBF can significantly inhibit the degradation of apoRBF by the protease(s) in simulated gastrointestinal fluid. Additionally， the antioxidant ability of EC in ferritin-EC complex(FEC) was retained but slightly decreased. This study clarified the interaction mechanism between polyphenols and phytoferritin， providing the theoretical reference for the application of non-covalent complexes between (-)-epicatechin and phytoferritin.

Abstract:Cooked wheat qu is a kind of wheat qu that pure culture of Aspergillus flavus， which is widely used in modern Huangjiu production. To explore the mechanism of cooked wheat qu in Huangjiu fermentation， the influence of cooked wheat qu on Huangjiu brewing was analyzed by controlling the proportion of it. Further， the autolysis characteristics of Aspergillus flavus mycelia (autolysis) was studied， and the influence of mycelia autolysis on Huangjiu was analyzed by co-culture experiment of Aspergillus flavus mycelia (autolysis) and spores (not autolysis) with yeast. The results showed that， with the increase of the proportion of cooked wheat qu added， the S. cerevisiae biomass in the fermentation system significantly increased by 37.61% to 135.90%， and the alcohol content， ammonia nitrogen， amino acid and organic acid significantly increased by 15.87%， 70.00%， 28.46% and 92.41% respectively. Furthermore， the study on the autolysis of Aspergillus flavus mycelium found that the autolysis of mycelium can provide amino acids， sugars， nucleotides and other biomolecules substances for the fermentation system， effectively increase the S. cerevisiae biomass in the fermentation system by 1.32 times， and significantly affect the content of ethanol， ammonia nitrogen， fusel and amino acids. Above all， on the one hand， cooked wheat qu can promoting Huangjiu fermentation by making use of its rich enzyme substances to promote the decomposition of raw materials； on the other hand， a large number of mycelium in cooked wheat qu has autolysis in the fermentation process， which provide nitrogen sources for the fermentation mash and affects the general parameters and flavor compound formation.

Abstract:Twelve-four Sunit lamb were equally allocated into two groups， which were fed a basic diet alone or supplemented with Lactobacillus. The effect mechanism on fat distribution and fatty acid profile of Sunit sheep was studied by measuring their fat distribution， fatty acids profile and metabolomics of longissimus thoracis (LT) and tail fat (TF). The results showed that the fat content of LT and biceps femoris (BF)， the content of myristic acid and docosahexenoic acid in LT and BF， palmitic acid， γ-linolenic acid and arachidonic acid in LT， monounsaturated fatty acid， palmitoleic acid and oleic acid in BF， cardamom oleic acid in subcutaneous fat(SF)， trans-oleic acid， trans-linoleic acid and α-linolenic acid in TF were significantly higher than that in the control group(P<0.05). The fat content of abdominal SF and the proportion of TF， the content of trans-linoleic acid in LT and BF， lauric acid in BF and SF， palmitic acid in SF were significantly lower than those in the control group (P<0.05). At the same time， significant changes in choline metabolism and fatty acids metabolism pathways of LT and TF were found based on metabolomics. Specifically， the levels of phosphocholine and cytidine diphosphocholine in LT of were significantly higher than those in control group， but the TF was opposite (P<0.05). The levels of oleic acid， α-linolenic acid in LT and palmitoleic acid， γ-linolenic acid in TF were significantly lower than those in control group (P<0.05). In conclusion， Lactobacillus affected the choline and fatty acid metabolic pathways of Sunit sheep to a certain extent， and then improved its fat distribution and fatty acids profile.

Abstract:In order to investigate the influence of concentration of AP to the storage stability and fatty acid accessibility， different concentration of AP (0-5 g/L) was applied as the stabilizer. The storage stability was determined by dynamic light scattering and visual stability. Meanwhile， the influence of in vitro simulated digestion on the protein structure， emulsion structure and fatty acid accessibility was also investigated using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis， dynamic light scatting technologies， confocal laser scanning microscopy， the release of fatty acid and gas chromatography. The results show that the storage stability of SOB and POB is highly dependent on the AP concentration when the AP concentration is less than 3 g/L. The storage stability of emulsions is significantly improved when the AP concentration is higher than 1.5 g/L， this is due to the decreasing of aggregation and increasing of surface charge values. When the AP concentration is between 3-5 g/L， the influence of pectin to the stability of emulsion reaches a balance statue. During in vitro simulated digestion， the activity of pepsin can be inhibited by adding AP， peptides below 15 ku is formed during the testing. The ζ-potentials of emulsion significantly reduces due to the formation of negatively charged peptides， increasing of bile salts， and releasing of free fatty acids. In the testing， the free fatty acid accessibility decreases by 3.3% with 1.5 g/L of AP compared with OBs without AP， this is due the inhibits of pepsin during the hydrolysis of OBs proteins and the controlling of SOB-AP size. However， the free fatty acid accessibility increases by 33.8% with POB. This is due to the bigger hydrolyzed area of trypsin in POB-AP.

Abstract:The dairy protein hydrolysis process can hydrolyze large molecule proteins into small molecule proteins and peptides. Infant formulas with partially hydrolyzed proteins may be beneficial to the digestion and absorption of infants， but the comparison between them and breast milk is unclear. In this study， a commercially available infant formula (EF) containing partially hydrolyzed protein was used to compare the in vitro digestion and absorption characteristics with standard infant formula (SF) and breast milk (BM)， and the amino acid score and digestible indispensable amino acid score were calculated based on the total amino acid pattern and digested amino acid pattern， respectively， to evaluate the protein quality. The results showed that the protein content of the two formulas was higher than that of BM， and the amino acid composition was close to that of BM. The in vitro protein digestibility was (33.50±0.39)%， (33.07±0.83)% and (38.49±0.51)% for EF， SF and BM， respectively， with the absorption rate of EF up to 78% of the BM. The results of digestible indispensable amino acid score showed that the limiting amino acids of EF were threonine and histidine， while all other amino acids scored above 75， which can be considered as good protein quality. Therefore， the infant formula containing partially hydrolyzed protein used in this study has better digestibility and absorption properties than the control formula and is closer to breast milk. This study can provide data to support the digestion and absorption characteristics of infant formula containing partially hydrolyzed protein and provide a theoretical basis for in vitro research methods for protein evaluation.

Abstract:Ulcerative colitis (UC) is an idiopathic intestinal disease with an increasing incidence， and all the therapeutic drugs have different degrees of side effects. Studies have found that collagen peptide can relieve the symptoms of UC， and is safe and healthy. However， the current research is mainly limited to the prevention effect of UC， and there is still a lack of research on the therapeutic effect of UC. Eel skin is rich in collagen， but eel head is generally discarded in processing， resulting in a waste of resources. Meanwhile， there is a lack of research on eel skin collogen hydrolysates. In this study， collagen was extracted from eel skin and hydrolyzed in the hope of obtaining eel skin collagen hydrolysate (CH) with therapeutic effect on UC， so as to improve the utilization value of eel processing by-products. It was found that eel skin contained abundant collagen， accounting for 27.87% of the wet weight of the skin. The extracted collagen was of high purity and mainly type Ⅰ collagen， and eel skin could be used as a high-quality source of collagen. Collagen was enzymatically hydrolyzed to obtain eel skin collagen hydrolysate (CH) with antioxidant activity， and CH was administered to DSS induced UC mouse model. The results showed that CH could safely and healthily reduce DAI score to 0 and improve colon status in UC Model mice compared with Positive control group and Model group. Pathological sections of colon tissue showed that CH could restore the integrity of mucosal epithelium and reduce inflammatory cell infiltration. Oxidative stress index of colon tissue showed that CH could reduce MDA content (0.75 nmol/mg protein) and MPO activity (0.11 U/g tissue) in colon tissue， and improve the antioxidant capacity of colon tissue and reduce oxidative stress level by increasing GSH content (22.92 umol/g pro) and activities of SOD (693.61 U/g pro)， CAT (1.69 U/g pro) and GPx (141.29 U/g pro) antioxidant enzymes， so as to treat UC.

Abstract:Objective: To explore the absorption characteristics of marine fish oligopeptide chelated iron (MCOP-Fe) in small intestine， and compare it with the traditional iron supplement-ferrous sulfate (FeSO4). Methods: 40 female Sprague Dawley rats were randomly divided into 8 groups (L-MCOP-Fe: 3 μg/mL MCOP-Fe； M-MCOP-Fe: 5 μg/mL MCOP-Fe； H-MCOP-Fe: 10 μg/mL MCOP-Fe； L-FeSO4: 3 μg/mL FeSO4； M- FeSO4: 5 μg/mL FeSO4； H-FeSO4: 10 μg/mL FeSO4； H-MCOP-Fe+PA: 10 μg/mL MCOP-Fe+500 μg/mL phytic acid； H-FeSO4+PA: 10 μg/mL FeSO4 + 500 μg/mL phytic acid). To establish the model of everted gut sac in vitro， the effect of iron absorption in different intestinal segments was evaluated by the cumulative iron absorption rate per unit area(Q). Results: 1) The Q values of duodenum， jejunum and ileum in three MCOP-Fe groups increased with concentration gradient， but there was no similar trend in FeSO4 groups； 2) The Q values of group L-FeSO4 and M-FeSO4 had a tendency to be higher than those of group L-MCOP-Fe and M-MCOP-Fe， but were opposite at high concentration (10 μg/mL)； 3) After adding 500 μg/mL phytic acid， the Q values of groups H-MCOP-Fe+PA and H-FeSO4+PA decreased compared with groups H-MCOP-Fe and H-FeSO4， and the decrease degree of group H-FeSO4+PA was more significant (P<0.05). Conclusion: In the range of 3-10 μg/mL， the absorption rate of FeSO4 in small intestine showed an equilibrium trend of saturation， while the MCOP-Fe showed a gradient trend of increase； at the same time， MCOP-Fe was less inhibited by phytic acid， and was more stable than FeSO4， which has good application prospects.

Abstract:Objective:The anti-obesity effect of Pu-erh tea and its ingredients has long been known， but few studies on this effect among different Pu-erh tea has been taken into account. In this experiment， two kinds of Pu-erh tea with obvious differences， namely RAPT (Pu-erh raw tea) and RIPT (Pu-erh ripe tea)， were used to prepare tea soup to feed C57BL6/J mice on a HFD (high-fat diet) to observe the differences in the intervention effects. The results shown that RAPT and RIPT not only had anti-obesity effects in terms of blood fat indicators， organ tissue changes， and intestinal flora， but also have significant differences in the intervention effects shown. RAPT can reduce blood TC and TG levels after 2 weeks of feeding， while Pu-erh ripe tea does not have this effect until 8 weeks； RAPT could reduce the level of LDL-C in the blood while RIPT could increase HDL- C. In liver lipid metabolism， both RAPT and RIPT could remarkably reduce the formation of fat droplets in the liver. After 8 weeks of feeding， RAPT significantly increased the abundance of Akkermansia， norank_f__Muribaculaceae， and Bacteroides in the intestinal flora and decreased the abundance of Romboutsia. RIPT could increase the abundance of Lactobacillus， norank_f__Muribaculaceae， and Bacteroides in the intestinal flora， and down-regulate the abundance of Romboutsia and Erysipelatoclostridium.

Abstract:To explore the protective effects of polysaccharide fermented milk from White Hypsizygusmarmoreus on intestinal tract， intestinal flora and antioxidant of mice，the polysaccharide fermented milk was prepared by using water extracted polysaccharide (WHN) and enzyme extracted polysaccharide (WHE) as experimental materials. The results showed that polysaccharide fermented milk increased fecal water content of mice. Colon index and colon length of mice in high-dose polysaccharide extraction group were 1.62 and 9.59 cm， which were significantly increased compared with blank group. Short chain fatty acids content in colon contents of high-dose polysaccharide extraction group was 26.45 mmol/L， 1.38 times of that in blank group. The contents of reducing sugars and monosaccharides increased significantly. Moreover， the intestinal flora species abundance in the group of the high dosage of fermented milk with WHN was highest， and the abundances of Bacteroidetes， Actinobacteria and Lactobacillus were increased at the genus and phylum levels by analyzing the Alpha diversity indexes. While the effects of the high dosage of fermented milk with WHE on antioxidant and anti-hyperlipidemic were the best， it could increase the activities of T-AOC， SOD and CAT， decrease the content of MDA. The findings indicated that the polysaccharide fermented milk from White Hypsizygusmarmoreus could play a key role in improving the intestinal physiology， regulating gut microbiota and enhancing antioxidant capacity in mice， providing research ideas and a theoretical basis for the polysaccharide fermented milk of from White Hypsizygusmarmoreus， WHE fermented milk group is better than WHN fermented milk group， in a certain dose dependence.

Abstract:Objective: To study the preventive effect of rape pollen extract on nonalcoholic fatty liver disease in mice induced by high-fat diet. Methods: The antioxidant activity of rape pollen extract was determined by DPPH and OH methods. Sixty mice were divided into normal group， model group， metformin group (200 mg/kg)， low-， medium- and high-doses rape pollen extract (2， 4， 8 g/kg). While the normal group mice were fed with regular diet， the other groups were fed with high-fat diet， at the same time， the drug was administered once a day. After 10 weeks of continuous feeding， the related biochemical indexes in serum and liver and the expression of p-AMPK and AMPK protein were detected. The pathological changes of liver were observed by HE staining. Result: The rape pollen extract has strong antioxidant capacity. After intervention， compared with the model group， the liver weight of mice in the high-dose group decreased significantly. In all intervention groups， the levels of AST， ALT， TG， TC and LDL-C in serum and TG， TC and MDA in liver tissue were significantly decreased， while the levels of HDL-C in serum and SOD in liver tissue were significantly increased. The expression of p-AMPK protein in liver tissue was significantly up-regulated， and the symptoms of liver pathological injury were improved. Conclusion: Rape pollen extract can prevent nonalcoholic fatty liver disease induced by high fat in mice， and its mechanism may be related to the regulation of AMPK signal pathway.

Abstract:To extract amygdalin from the peach kernel， a by-product of white peach processing， and study its in vitro biological activities. A single-factor experiment was carried out under different drying methods. Based on microwave drying， the extraction process was optimized by response surface methodology. The study of anticoagulant， hypoglycemic and hypolipidemic activities of amygdalin were carried out by in vitro analysis， and the interaction between amygdalin and enzyme was studied by molecular docking. The optimal extraction conditions of amygdalin were as follows: ethanol volume fraction 81.43%， extraction temperature 68.91 ℃ and extraction time 20.00 min. Amygdalin prolonged the activated partial thromboplastin time and thrombin time， reduced the content of fibrinogen. Moreover， amygdalin inhibited the catalytic activities of α-amylase， α-glucosidase and pancreatic lipase. Meanwhile， it could combine with taurine cholate and glycine cholate. Molecular docking analysis showed that amygdalin from the peach kernel could form hydrogen bonds with hydrophilic amino acids of α-amylase， α-glucosidase and pancreatic lipase， which might change the molecular conformation of enzymes or form competitive inhibition with the substrate. Results indicated that amygdalin in the peach kernel showed effectively in vitro anticoagulant， hypoglycemic and hypolipidemic activities. The results of this study provide a reference for the efficient extraction of amygdalin in the peach kernel and the further utilization of peach kernel.

Abstract:In this study， ultrasonic-assisted method was used to extract total flavonoids from sea buckthorn fruits. The extraction process was optimized by the single factor test and the response surface test. The distribution and contents of four main flavonoid aglycones from sea buckthorn fruits of different maturities and different regions were determined by the optimized extraction process combined with high-performance liquid chromatography. Thereafter a comparative study of the antioxidant activity of sea buckthorn flavonoids extracts was carried out. The optimal extraction conditions were determined as follows: ethanol concentration 55%， solid-to-solvent ratio 1∶45(g/mL)， and ultrasonic power 210 W. The extraction rate of sea buckthorn A total flavonoids was up to 3.241% under the optimized conditions. The main flavonoid aglycones in sea buckthorn fruits were isorhamnetin， quercetin， kaempferol and myricetin， and the content of flavonoid aglycones varied with the maturity and region of the fruit. Total flavonoids extract from the sea buckthorn C fruits exhibited strong antioxidant activities as determined by 1，1-diphenyl-2-picrylhydrazyl (DPPH)， 2，2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical scavenging and ferric reducing antioxidant power assays. The total flavonoid aglycones content was significantly positively correlated with the DPPH radical scavenging capacity and ferric reducing power. In summary， this study can provide a scientific basis for the comprehensive utilization and development of sea buckthorn fruits.

Abstract:In this study， the fermentation condition of glucanase production by Burkholderia pyrrocinia B1213 has been optimized. Firstly， cultural conditions (variety of carbon sources， particle size and mass concentration of carbon source， variety of nitrogen sources， mass concentration of nitrogen sources， shaking speed， temperature， liquid medium volume， inoculum volume， initial pH， variety of surfactants， mass concentration of surfactant and fermentation time) of B1213 were optimized by single-factor experiments. Then， four factors， signally affect production of glucanase by B1213 fermentation， were obtained by Plackett-Burman tests. The maximum response area of glucanase activity was determined by steepest ascent. Finally， Box-Behnken Design were used to ascertain the optimal condition of glucanase production. The optimal condition were: 40-60 mesh of wheat bran 50 g/L， yeast extract 8 g/L， initial pH 6.6， liquid medium volume 30 mL/250 mL， inoculum volume 0.15%， Triton X-100 25 g/L， incubating temperature 30 ℃， shaking speed 160 r/min and fermentation time 83 h. Under the optimal condition， the activity of glucanase produced by B1213 were achieved 1 230 U/mL. This study provides academic value for application of bacteria B1213 in Baijiu brewing from the aspect of enzymes related to degradation of raw material for Baijiu brewing.

Abstract:This study was to explore the new GH134 family mannanase and its application potential for synergistic preparation of konjac mannan oligosaccharides with heterogeneous hygrothermal technology. In this paper， a new GH134 family mannanase (RmMan134B) was successfully obtained from the genome of Rhizopus microsporum GZHF10， which encoded 181 amino acids and a stop codon. The sequence identity with the reported GH134 mannanse was low (<69.6%). So the E. coli PET expression system was used for heterologous expression and property analysis， and the results showed that the most suitable substrate for the enzyme was konjac mannan， and the optimum temperature and pH were 40 ℃ and 5.0. Amorphophallus konjac powder was subjected to heterogeneous hygrothermal treatment at 115 ℃ and 0.1 MPa. The structure and properties of konjac were changed significantly. After 2 h of treatment， the apparent viscosity (30 g/L) of the solution of konjac flour was reduced 96.1%， the particle size of the powder was reduced， the thermal stability was improved， and the hydrolysis rate of the modified konjac flour was increased by 0.6-1 times. Further study found that the main components of RmMan134B enzymatic hydrolysis products are monosaccharides (0.922 mg/L)， disaccharides (1.4 mg/L) and trisaccharides (0.613 mg/L). This research had a certain role in promoting the efficient utilization of konjac mannan resources and the development of industrialization.

Abstract:Natural chitin has the characteristics of high molecular weight， high crystallinity and difficult enzymatic hydrolysis， which greatly limits its development and application. In order to improve the utilization rate of chitin， commercial non-specific enzymes with high degradation ability and good economic benefits were screened in this study， and their enzymatic hydrolysis effects on chitin after three modification methods (ultra-micro grinding， high-pressure homogenization， ultra-micro grinding-high-pressure homogenization) were evaluated. Determine the best modification method， optimize enzymatic hydrolysis process and analyze enzymatic hydrolysis products. The results showed that among the seven non-specific enzymes， papain had the highest chitin degradation ability and the lowest cost. The combined pretreatment of ultra-micro grinding and high-pressure homogenization method made chitin have higher degradability， the optimum conditions for degradation of chitin by papain were temperature 50 ℃， pH 7.0， enzyme mass concentration 10 mg/mL， time 14 h. The results of thin layer chromatography showed that(GlcNAc)3-6 four degrees of polymerization of chitin oligosaccharides were produced at the initial stage of enzymatic hydrolysis(1 h)， which preliminarily proved that papain could break the β-1，4 glycosidic bond of chitin； the results of ion chromatography analysis showed that only GlcNAc and (GlcNAc)2 were found in the enzymolysis products after enzymolysis equilibrium (14 h)， and the mass concentrations were 22.26 mg/mL and 58.75 mg/mL， respectively.

Abstract:In order to reduce the contents of biogenic amines (BAs)， N-nitrosamines (NAs) and nitrite residues in air-dried sausages and improve the safety and quality of products， four groups of air-dried sausages were designed， 1) MNI group: 0.05% microbial nitrosation inhibitor was added； 2) MNIP group: add 0.05% MNI and inoculation PRO-MIX5 commercial starter (Staphylococcus xylose， Lactobacillus sake， Lactobacillus plantarum)； 3) FBFAP group: add exogenous additives and inoculation PRO-MIX5 commercial starter； 4) CK group: blank control group. The four groups of samples after filled were fermented in a constant temperature and humidity incubator at 30 ℃. When the pH value decreased to about 5.4， the fermentation was terminated and entered the air drying maturation process of 20 days (14-16 ℃). The changes of pH value during fermentation， pH value， moisture content， aw， color difference， thiobarbituric acid reactive substances (TBARs) value and changes in BAs during ripening (1， 5， 10， 15， 20 d)， as well as the content of NAs and nitrite residue of air-dried sausage products in the four groups were measured. The results showed that in the fermentation stage， the pH value of MNIP group and MNI group decreased rapidly to 5.4 at 12.5 h and 15 h respectively， while FBFAP group and CK group reached the required pH range at 21 h and 22 h. The pH value of the samples in MNIP group and MNI group was always significantly lower than that in FBFAP group and CK group (P < 0.05). The pH value of the finished products of air-dried sausages in the two groups reached 5.08， which was conducive to improving the safety and quality of air-dried sausages. The water content (28.91%， 28.72%) and aw (0.75， 0.77) of air-dried intestinal products in MNIP group and MNI group were significantly higher than those in CK and FBFAP group (P < 0.05)， which was conducive to obtain better sensory quality on the premise of safety quality. Compared with CK group， MNIP group， MNI group and FBFAP group had higher L* values (54.94， 54.05， 48.83) and a* values (13.62， 13.57， 14.54)， lower TBARS (0.34-0.36 mg/kg)， and the levels of histamine， tyramine， cadaverine and tryptamine remained low. MNIP， MNI and FBFAP can effectively inhibit the formation of NAs in air-dried sausage， and the inhibition rates of NAs are 54.77%， 51.31% and 37.10% respectively. MNIP group has the best inhibition effect. The nitrite residues in the air-dried sausages of the four groups remained at a low level (2.19-4.43 mg/kg). Therefore， the synergistic effect of MNI and PRO-MIX5 commercial starter can significantly improve the physical and chemical properties and safety quality of air-dried sausage.

Abstract:In order to study the effects of different salinities on the volatile flavor compounds and physicochemical properties of red cabbage sauerkraut during the fermentation， there were four different salt concentrations of 1%， 3%， 5%， and 10% were designed. The volatile flavor compounds (VOCs) in red cabbage sauerkraut were detected by using the headspace solid-phase microextraction-gas chromatograph-mass spectrometry (HS-SPME/GC-MS) The differences of VOCs as well as sensory scores， pH， total acidity， nitrite， amino acid nitrogen， reducing sugar content and number of lactic acid bacteria (LAB) colonies in different samples were analyzed during the fermentation. The results showed that salinity had a significant effect on the sensory score of red cabbage sauerkraut and physicochemical indexes such as the pH， total acidity， amino acid nitrogen， reducing sugar content and the number of LAB colonies (P<0.05). High salinity (>5%) is not conducive to the fermentation and sensory quality of sauerkraut and fermented at 3% salinity has the highest sensory score. The results of HS-SPME/GC-MS analysis showed that at the end of fermentation (60 days)， the total content of flavor substances in red cabbage sauerkraut fermented at 3% salinity was the highest. Among them， the content of some flavor compounds such as alkenes， alcohols， aldehydes， ketones， isothiocyanates and nitriles was significantly higher than that of sauerkraut with other salinity (P<0.05). With the increase of salinity， these flavor substances decreased accordingly. Combined with odour activity values (OAVs) analysis， 21 key VOCs in sauerkraut were obtained， and it was found that their OAVs would be significantly reduced (P<0.05) at higher salinity (>5%). According to principal component analysis (PCA)， in the middle (30 days) and end (60 days) of fermentation， the component of flavor substances in sauerkraut fermented at different salinity was not quite similar， and the flavor substances at 3% salinity were more abundant. The Pearson correlation analysis disclosed that there was negative correlation between salinity and total acidity (P<0.05)， amino acid nitrogen， LAB number， sensory scores as well as most volatile flavor compounds while the salinity was positively correlated to pH and reducing sugar content. Conclusion: Compared with other salinity， red cabbage fermented at 3% salinity has better flavor quality， and can be directly used in red cabbage sauerkraut making， which has certain guiding significance for processing red cabbage products.

Abstract:Variations in water holding capacity， moisture distribution， protein degradation and taste ingredients of Antarctic krill meat after low temperature thawing， water soaking thawing， ultrasonic thawing，or air thawing were investigated to explore the effect of thawing methods on the quality of frozen Antarctic krill meat. The results showed that low temperature thawing or water soaking thawing endowed Antarctic krill meat with better water retention capacity and complete internal water structure when compared to ultrasonic thawing or air thawing； low temperature thawing took a longest time (98.42 min)， but the content of TCA-soluble peptides after thawing was significantly lower than those of the other three groups (P < 0.05)； and the proportion of umami amino acids was significantly higher than those of the other three groups (P < 0.05)； ultrasonic thawing took the shortest time (21.83 min)， but the content of the non-protein nitrogen (NPN) content after thawing was the largest (P < 0.05). The proportion of essential amino acids for air thawing was 11.58%， which was significantly lower than those in the other three groups (P < 0.05). There was no significant difference in the content of total volatile base nitrogen (TVB-N) among the four groups (P > 0.05)， and all of them were below 10 mg/100 g. The taste activity value (TAV) indicated that the sweetness and bitterness were the main taste of thawed Antarctic krill meat， and the proportion of bitter amino acids in Antarctic krill meat after air thawing was the largest (P < 0.05). The above results indicated that low temperature or water soaking thawing were more suitable for the thawing of Antarctic krill meat， while the quality of Antarctic krill meat after ultrasonic thawing or air thawing was relatively poor.

Abstract:This article studied the effects of papain and ultra-high pressure tenderization on the tenderness and nutritional quality of Bactrian camel tendon meat. Experiments on papain concentration， solvent pH， tenderization temperature， tenderization time， ultra-high pressure level， and pressure time， by measuring the cooking loss， water power， pH value， color， texture characteristics and maximum shear force of camel meat， the best conditions for tenderizing camel meat with two treatment methods were screened out. The results showed that the tenderness of camel meat was improved after papain and ultra-high pressure tenderization. The optimal tenderization conditions for papain are: enzyme concentration 120 U/mL， solvent pH 6， tenderization temperature 55 ℃， tenderization time 2 h； the optimal tenderization conditions for ultra-high pressure are: pressure value of 250 MPa and pressure treatment time of 20 min. The shearing force of camel meat tenderized by papain is significantly reduced， and the effect of ultra-high pressure tenderization is not as obvious as that of enzyme tenderization， but it can better protect the nutrients in the meat. The research results provide a basis for the application of related tenderization technologies for livestock and poultry meat， and also lay a foundation for the subsequent development of camel meat and related products.

Abstract:In order to research the effect of soy protein and its modified products on the quality of steamed bread， soybean proteins were added into flour in different ratio， texture properties， sensory evaluating value and physicochemical properties of the steamed bread， and the properties of flour and dough were determined. The results showed that dough development time and dough stability increased by 2.5 min after adding 1.5%， and that of adding 4.5% TSP dough increased by 1 min， but decreased by about 6 min after adding 1.5% SPH. After adding and 4.5% TSP， the gluten index and the air-holding capacity of the dough increased by 2.22%， but the air-holding capacity decreased after adding 1.5% SPH. Adding 1.5% SPI and 4.5% TSP could increase the contents of SDS soluble glutenin and glutein macropolymer (GMP)， and improve the springiness and moisture content of steamed bread. However， adding 1.5% SPH reduced the contents of SDS soluble glutenin and GMP， and decreased the springiness of steamed bread. Conclusion: by studying the quality of steamed bread， it is found that the quality of steamed bread is the best when the addition of SPI， TSP and SPH is 1.5%， 4.5% and 1.5% respectively. Through the study on the optimum amount of mixed flour of each soy protein， it is found that different kinds of soy protein have different effects on the quality of steamed bread.

Abstract:In order to explore the influence of rice flour variety and particle size on the mechanical properties of cake batter and the quality of finished products， this experiment took japonica rice， indica rice and glutinous rice as the research objects， and prepared 80 mesh， 100 mesh， 120 mesh and 140 mesh rice flour respectively. Texture， basic rheological properties and textural properties and sensory qualities of finished cakes were detected analyed. The basic analysis showed that with the decrease of particle size， the content of damaged starch increased， the maximum content of damaged starch in 140 mesh glutinous rice flour was 23.1%. The dynamic rheology results of cake batters show that all cake batters were more elastic than viscous， and all exhibit semi-solid-like behaviors， which were preliminarily determined to be viscoelastic fluids. The G′ value of indica and japonica rice flour cake batter were higher than those of glutinous rice flour， and the G″ value was lower than that of glutinous rice flour； with the decrease of particle size， the G′ value of indica and japonica rice flour batter increased and the， G″ value decreased， whereas glutinous rice flour was the opposite. The results of large deformation texture properties of cake batter showed that the elasticity and recovery of japonica rice flour， indica rice flour and wheat flour cake batter increased with the decrease of particle size， and the cohesiveness decreased with the decrease of particle size， while the glutinous rice flour decreased as the particle size decreased. Powder cake batter was the opposite. The texture results of cakes showed that with the decrease of rice flour particle size， the hardness of cakes increased； the hardness of rice flour cakes was higher than that of wheat flour cakes， and the hardness of indica rice flour cakes was significantly higher than that of wheat flour and other varieties. According to sensory analysis， the japonica rice flour with a particle size of 120 mesh has the highest score. The elastic modulus had a significant positive and extremely significant positive correlation with the protein and amylose content， respectively， and had a significant negative correlation with the damaged starch content. The viscosity modulus has a very significant negative correlation with the amylose content. For rice flour with different particle sizes， there is a significant correlation between the texture properties of cake and the rheological properties of cake batter. The changes of G′ and G″ in the basic rheology of cake batter can predict the change of cake texture.

Abstract:The drying method has great influence on the physicochemical properties of resistant lotus root powder. In order to study the effect of spray drying synergistic enzymatic preparation on resistant lotus root powder， lotus root powder was used as raw material to prepare resistant lotus root by using pressure-heat cooling cycle， spray drying synergistic high temperature resistant α-amylase and pullulanase， respectively. The modification effects of different methods were compared by the yield， texture， rehydration， microstructure and infrared spectrum characteristics. The results showed that the yield of resistant lotus root powder prepared by spray drying synergistic pullulanase was 5.3%， which was significantly higher than other treatment groups (P < 0.05)， while the yield by spray drying synergistic α-amylase was second highest (4.6%) and pressure-heat cooling cycle was the lowest (2.7%). Spray drying synergistic enzymatic could decrease the hardness， elasticity， adhesion and cohesion of lotus root powder. The particles prepared by enzymatic hydrolysis were rough， with obvious cracks and larger particles， while the particles prepared by spray drying synergistic enzymatic were uniform and delicate with smooth surface. Compared with the original lotus root powder， spray drying synergistic preparation could narrow the characteristic absorption peaks (3 500-3 200 cm-1) and shift the peak (990 cm-1). Therefore， spray drying synergistic enzymatic could increase the amorphous area， reduce the branching chains and reduce the viscosity， and make the lotus root powder have better resistance and flushing property.

Abstract:Objective: In order to improve the sour taste of kiwi fruit wine and take advantage of the potential advantages of non-Saccharomyces cerevisiae to regulate the organic acid content， enrich the body aroma and taste， this research aims to use the biological acid reduction properties of Pichia kudriavzevii to brew kiwi wine. Methods: With commercial Saccharomyces cerevisiae CECA as the control strain， 17 non-Saccharomyces cerevisiae strains preserved in the laboratory were screened to obtain Pichia kudriavzevii strains with higher acid metabolism ability. Through exploring its growth conditions under different sugar concentration， alcohol content， temperature and acid content， the biological characteristics and fermentation performance were studied， and it was found that the oxygen supply during the fermentation process greatly enhanced the degradation of yeast in kiwi wine brewing. The acid effect was then sensory evaluated by the tasting team. Result: Pichia kudriavzevii strain GS1-1 has good acid-reducing ability and has similar fermentation performance with Saccharomyces cerevisiae. Fermentation under different oxygen conditions show that the addition of oxygen has a significant effect on the acid reduction rate. The decreasing rate will increase 24.6% under through-oxygen condition， adding oxygen to the environment is more conducive to degrading the content of kiwi acidity. After tasting， the taste is soft， giving the kiwi wine the aroma characteristics of tropical fruits and citrus. Conclusion: In the wine brewing industry， it is of great significance to screen strains with acid-reducing ability to improve their acid-reducing effect， and changing the oxygen environment is a potential means to improve the viability of utilizing yeast to improve the quality of wine. The yeast GS1-1 can be used as an ideal material to further study its acidity reduction and aroma enhancement in fruit wine.

Abstract:Present study investigated the effects of storage temperature on the physiology and fruit quality of 'Huangfei' cherry tomato. The results showed that， 'Huangfei' cherry tomato is tolerated to the above 0 ℃ low temperatures， without any chilling injury syndrome occurred in the 15 d storage. The ethylene release rate and respiratory rate showed a general trend of decrease with the elongation of storage time. A peak of ethylene release rate existed in the 20 ℃ and 16 ℃ groups at the 15 h. Both the ethylene release rate and respiratory rate were significantly higher in the 20 ℃ and 16 ℃ groups compared to the fruit stored under lower temperatures. The weight loss rate， fruit decay rate， color， freshness of carpel and sepals were significantly affected by the storage temperature， with the lower temperatures being more beneficial for the improvement of these index. The fruit hardness， TSS and TA contents remained stable in the 15 d storage， which were affected less by the storage temperature. The results of fuzzy sensory evaluation by Electric-tongue indicated that the flavor quality changed after storage， and the lower temperatures were more beneficial at maintaining the fruit quality. Taking the fruit loss and fruit quality into general consideration， 0-8 ℃ was suitable to be applied for the storage of 'Huangfei' cherry tomato.

Abstract:Objective: To investigate the chemical constituents and antioxidant activity from Citrus reticulate Blanco superior plants fruit peel， and explore the potential effect about it. Methods: To study the chemical constituents of Citrus reticulate Blanco superior plants fruit peel by using HPLC-DAD-ESI-MS/MS and GC-MS， evaluation of their antioxidant activity by DPPH method， ABTS method， ferric reducing antioxidant power (FRAP) and measurement of lipid peroxidation by thiobarbituric acid reactive substances methods (TBARS). Targets related to antioxidant were screened by Network pharmacology， and used for GO functional and KEGG enrichment pathway analysis and construct the network of active ingredients-targets-pathway by Cytoscape 3.8.2， and molecular docking was used to verify the interactions between the main active ingredients and the key targets of Citrus reticulate Blanco superior plants fruit peel. Results: The HPLC-DAD-ESI-MS/MS results showed that 32 compounds and GC-MS results showed that 33 volatile components were identified of Citrus reticulate Blanco superior plants fruit peel. In vitro antioxidant experiments showed that has significant antioxidant capacity. The network pharmacology and molecular docking results showed that the flavonoid components such as Naringenin and TP53， MAPK3 and other targets matched well. Conclusion: This study initially explored the potential mechanisms of multi-component， multi-target and multi-pathway antioxidant intervention of Citrus reticulate Blanco superior plants fruit peel， providing new possibilities for the further development about it as functional food ingredients or functional feed.

Abstract:In order to study the changes of metabolites in winter jujube after cold storage， ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to analyze the metabolisms in postharvest winter jujube before and after cold storage. The metabolisms in cold stored differential times and without cold stored winter jujube were compared by principal component analysis and correlation analysis， orthogonal partial least squares discriminant analysis and other statistical analysis. The results showed that a total of 794 metabolites belonging to 13 kinds were identified in winter jujube， 93 and 154 differential metabolites were respectively screened out in refrigerated winter jujube for 60 d and 90 d. These results indicated that refrigeration had an impact on the quantity and content of differential metabolites， especially the content. The metabolic pathways of differential metabolites enrichment analysis found that the differential metabolites in the cold stored for 60 d and 90 d winter jujube were mainly in the metabolic pathway， the secondary metabolites biosynthesis pathway， linoleic acid metabolism pathway， flavonoid biosynthesis pathway， flavone and flavonol biosynthesis pathway. The results provided theoretical basis for studying the mechanism of fruit quality deterioration of cold-stored winter jujube.

Abstract:The number of microbial groups， pH and aw values of 39 bacons collected from different regions of Sichuan were determined. The yeast strains were isolated and purified from the PDA counting plate， identified by morphological and biochemical characteristics combined with 26S rDNA D1/D2 region sequence， and evaluated biological and aroma-producing characteristics of 24 strains of yeast. The results showed that the range of aw and pH of Sichuan bacon were 0.8-0.9 and 5.0-6.0 respectively except for a few samples. Lactic acid bacteria and Staphylococci are the dominant microorganisms in Sichuan bacon， and the number of yeasts in samples collected from mountainous areas all exceeded 4 lg (CFU/g). A total of 113 yeast strains were isolated from Sichuan bacon， including Meyerozyma guilliermondii， Debaryomyces hansenii， Rhodotorula mucilaginosa， Candida zeylanoides， Cryptococcus albidus and Naganishia diffluens， of which M. guilliermondii and D. hansenii were found as the dominant species accounted for 28.3% and 23.9%， respectively. Most of the tested strains exhibited good tolerance to processing environment and extracellular lipase and catalase activity. Interestingly， it can significantly increased the content of 3-methylbutanol and phenethyl alcohol and reduced the production of furfural， benzaldehyde and dimethyl benzaldehyde in the three inoculated groups. In conclusion， yeast of Sichuan bacon has rich diversity and good technological properties， and has potential application value and development prospects.

Abstract:A strain of lactic acid bacteria isolated from wine natural fermentation was identified through morphological observation and molecular biology， also the α-L-arabinosidase activity， α-L-rhamnosidase activity and β-D-glucosidase activity of which were determined to evaluate its glycosidase activity. Results showed that the isolated strain was Lactobacillus brevis and it possessed α-L-arabinosidase activity， α-L-rhamnosidase activity and β-D-glucosidase activity. These enzymes showed high activities at the stationary phase of growth， and mainly existed in the intracellular form and intact cells of the strain. Three carbon sources showed different effects on the enzyme activities of isolated strain. Compared with glucose as carbon source， cellobiose and arbutin promoted β-D-glucosidase activity， while they inhibited α-L-arabinosidase activity. Arbutin promoted the α-L-rhamnosidase activity， while cellobiose inhibited the α-L-rhamnosidase activity. This study provided a theoretical basis for developing new lactic acid bacteria strains in wine making and improving the wine quality.

Abstract:To improve the flavor of surimi-based products， the effects of the addition of six vegetable oils (2 mL/100 g of peanut， soybean， corn， coconut， olive and safflower seed oils) on the odor， volatile compounds and sensory characteristics of the Nemipterus virgatus surimi gel were compared， and investigated the effect of vegetable oil types on the improvement of the flavor of surimi gel. The results showed that the addition of six vegetable oils could improve the odor of the Nemipterus virgatus surimi gel， and increase the content and specie of volatile compounds such as aldehydes， ketones and hydrocarbons (P < 0.05). Among them， the gel with coconut oil was detected with the most species of volatile compounds， with 67 kinds. In the gel with coconut oil， there are as many as 10 compounds with odor activity value ≥1， which is significantly more than the control and the gel with other vegetable oils (P < 0.05). And their key odor components were mainly 2-heptanone， ethyl octanoate， 2-undecanoate， ethyl decanoate and butyl decalactone with fresh， coconut and fruity aromas， which together formed the unique flavor of the gels and improved the overall acceptability of the gels， while the key odor components in the gels with other vegetable oils were mainly aldehydes and alcohols. In conclusion， vegetable oils all could improve the flavor of the Nemipterus virgatus surimi gel， and coconut oil was the most effective and more suitable for developing surimi products with good flavor.

Abstract:Carotenoids are important lipid-soluble pigments in tea plants， which contributes to various key aromas as precursors. In this study， targeted metabolomics was applied to qualitative absolute content of carotenoids in tea leaves， and it was clear that the total content was (859.98±60.20) μg/g， which lutein contributed the highest ones as (405.06±17.71) μg/g. In made black and green tea， which manufactured by traditional black tea and green tea processing respectively， absolute content of carotenoids remained nearly half inside which decreased more than 50% compared with fresh leaves [(406.17±32.21) μg/g and (433.95±36.21) μg/g respectively]. Interestingly， spraying exogenous methyl jasmonate solution (0.25%) on tea leaves will greatly impact on the constituents of carotenoids. Especially in made green tea which was prepared from tea leaves treated with methyl jasmonate(12 h)， carotenoids greatly remained in made tea as high content of (682.69±46.12) μg/g， however， decreased in made black tea [(433.95±36.21) μg/g]. Fourteen carotenoid-derived aroma components were identified with significantly increase in black tea and green tea prepared from fresh leaves induced by methyl jasmoante for 24 h， especially the relative contents of β-damascenone， β-ionone， geranyl acetone and dihydroactinidiolide increased >2 times. Our results ensured acknowledge of carotenoids constituent and content in tea， promised a clear vision of carotenoids dynamics before， during， and after tea processing. It was confirmed that aroma quality of made teas (green tea and black tea) were greatly improved especially after 12 h and 24 h MeJA treatment time duration， and furthermore maintained a higher content of carotenoids. In conclusion， this study unraveled the mechanism of carotenoids content improvement in tea treated by methyl jasmonate. This will greatly improve our knowledge on taking advantage of exogenous application in tea quality improving.

Abstract:In order to explore the changes of salted egg yolk aggregation and the key control point in the salting process of Sansui salted egg in Guizhou Province， based on the low-salt salting technology， and through the detection of sodium chloride， changes of protein-related indexes in egg yolk aggregation. The results showed that the 8 days before pickling， ionic bond and hydrophobic interaction increased， the hydrogen bond and disulfide bond decreased， the ratio of α-helix to β-sheet decreased， the ratio of γ-random structure to β-turn increased， the secondary structure of protein changed， and the protein denatured， NaCl alters the structure of the low-density lipoprotein， and the yolk's protein-fat emulsion system was broken， but didn't coalesce to form a gelatinous structure. When salted for 12-16 d， the ionic bond strength decreased， the hydrogen bond， hydrophobic interaction and disulfide bond content increased， the proportion of α-helix structure continued to decrease， the proportion of γ-random， β-sheet and β-turn structure increased slightly， and the protein molecules of egg yolk aggregated， and there was a more obvious sense of loose sand mouth， oil output in more than 40%. During curing for 16-28 d， the structure of the low-density lipoprotein continued to renew， and the water loss from the yolk provided a more favorable environment for the accumulation of lipid molecules to form oil droplets， the dehydration of the yolk and the binding of the protein gels result in the final globular coagulation of the yolk. Through observing the microstructure of egg yolk coagulation part during curing， it was found that the yolk particles are gradually reduced and closely arranged， and there was cross-linking between them， this was the salted egg yolk after the production of a special loose sand feeling the main reason. Finally， it was concluded that curing 12 to 16 days was the key stage for the formation of the special loose sand taste of salted egg yolk and the appearance of oil seepage.

Abstract:Sirtuin is a NAD+-dependent protein deacylase that can cleave off acetyl and other acyl groups from the ε-amino group of lysines in histones and other substrate proteins. Studies have shown that Sirtuin is an important target for regulating diseases by calorie restriction (CR). It participates in development of various human age-related diseases， including metabolic syndrome， cancer， cardiovascular disease and neurodegenerative disease. In recent years， numerous evidences indicate that various compounds activate Sirtuin to simulate the effects of CR in preventing and regulating diseases. To better understand the underlying mechanism of Sirtuin in these diseases， and to screen Sirtuin-activating food components， this article focuses on the latest developments in Sirtuin-regulated signaling pathways， and summarizes the mechanism of foodborne Sirtuin activators in disease prevention.

Abstract:Food allergy is a serious public nutrition and hygiene problem that affects the quality of life of allergic people. At present， the research on food allergy has gone deep into the genetic level. In recent years， it has been reported that epigenetics plays a role in food allergy. These reviews summarize the effect of common epigenetic modifications such as DNA methylation， miRNA regulation， and histone modification on food allergy， exploring the gene-level formation mechanism of food allergy.

Abstract:Based on the need of product texture and taste， animal fat is indispensable in daily diet. However， excessive consumption of animal fat is conducive to human health. The use of vegetable raw materials to prepare mimic animal fat is one of the research hot-spots in the field of grain and oil processing. The research progress of the preparation of mimic animal fat and its food applications was summarized， and the development trends and prospects were also discussed and analyzed.

Abstract:Mycotoxin pollution in agricultural products not only causes huge economic losses in the agricultural industry， but also directly endangers human health. Although physical and chemical methods have played a certain role in the early removal of mycotoxins， the removal of mycotoxins by microorganisms is increasingly recognized as a safe， efficient and economic way. In this paper， two main removal methods (adsorption and degradation) of common mycotoxins in agricultural products by microorganisms are reviewed. The former mainly includes lactic acid bacteria and yeasts， and the removal of aflatoxin， zearalenone， deoxynivalenol， ochratoxin， T2 toxin， fumotoxin B1， patulin and other mycotoxins by bacteria adsorption is better； the latter are concentrated in Rhodococcus， Bacillus， Pseudomonas and yeast， which rely on microbial metabolism to degrade the above toxins. By summarizing the research reports， this paper summarized the research progress of common mycotoxins removal strains and their metabolic mechanisms， as well as the innovative changes in the detoxification of agricultural products mycotoxins.

Abstract:Depression is a common illness that severely limits psychosocial functioning and diminishes quality of life. The mechanisms of depression are very complex， and most of antidepressants have problems such as low treatment rate， delayed response and side effects. In recent years， researcher gradually pay attention to natural active ingredients， especially those that are homologous to medicine and food， for effective， safe and low toxic antidepressant substances. This article reviewed researches on the mechanism of depression and natural active ingredients in recent years. It was expected to provide ideas for screening new safe and effective antidepressant compounds， and theoretical basis for developing novel antidepressant products.

Abstract:With the improvement of science and technology and people's living standards， fermented foods are increasingly favored by people. Fermentation can not only improve the flavor and texture of food products， but also introduce new nutritional functions to them， thus further raising the added value of crops. However， the change of the color and attenuation of the product are very obvious during the fermentation process， especially for the raw materials rich in anthocyanins. The degradation of anthocyanins， the adsorption of anthocyanins by microorganisms， and the interaction between metabolites and anthocyanins will all influence the appearance of the color of products. This article reviewed the effects of microorganisms widely used in the fermented food industry in recent years (such as yeast， lactic acid bacteria， acetic acid bacteria， and mold) on the stability of anthocyanins， as well as the color and functional quality of products. In addition， the mechanism of microorganisms and metabolites in relation to the degradation of anthocyanin and the production of derivatives was analyzed in order to improve the color and functional quality of fermented food， from which was expected to provide basic and theoretical data for a wide range of applications of anthocyanins in food processing.

Abstract:The introduction of artificial sweetener saccharin in 1879 initiated the search for a new dietary paradigm of taste substitution. Currently， naturally derived sweeteners with very low or no calorie are becoming common ingredients in the daily diets of diabetics， and even becoming a new trend in health-promoting dietary patterns for the whole population. However， simple "zero"-sugar substitution not only fails to limit calorie intake， but even does the opposite by causing new health problems. Moreover， in addition to sweet taste， salty and fatty taste are also closely related to health. It is therefore absolutely not enough to replace only the sweet taste in diet. Only by comprehensively replacing the main sugar， fat and sodium that present taste in all foods， and developing a new healthy dietary model that preserves the satisfaction of eating while reducing the health hazards of food， can the public eat more healthily without deliberately changing their dietary habits and preferences. In this paper， focusing on the evolutionary and behavioral aspects of eating， the physiology of taste， and the physiology and pathology of taste substitution， the aim to explore the feasibility， problems and challenges of shifting from the "three reduction" dietary model to the "three substitution" healthy diet (sugar， salt and oil substitutes)， and discuss the healthy kitchen model based on the "three substitution" practice.

Abstract:The high molecular weight glutenin subunit forms the skeleton by intermolecular disulfide bond， while the low molecular weight glutenin subunit binds to the skeleton by disulfide bond， and the aggregates are further formed by non-covalent interactions such as hydrophobic interaction， hydrogen bond and electrostatic interaction between the skeletons. Aggregates that are so complex that even sodium dodecyl sulfate solution cannot disperse or dissolve are called glutenin macropolymer. The aggregation and deaggregation of glutenin macropolymer has great influence on flour production， dough viscoelasticity and relative sensory quality. The article summarizes the variation in glutenin macropolymer content and aggregation behavior from wheat kernel to flour and dough processing. During wheat storage， the content of glutenin macropolymer increased， indicating that glutenin gradually accumulated. In the center of wheat， the proportion of glutenin macropolymer to total protein was higher， indicating that more protein aggregation occurred in grain center. When mixing flour and water to form dough， the glutenin particles absorb water and swell， and the glutenin macropolymer content gradually decreases， indicating that the aggregation degree decreases as well. During the resting process， glutenin macropolymer content increased， indicating glutenin reaggregation. The analysis of dynamic equilibrium of protein aggregation and deaggregation at different levels is helpful to reveal the mechanism of glutenin macropolymers changes in wheat dough processing， which has importance in modulating gluten formation and dough viscoelasticity.

Abstract:In order to investigate the relationship between the intake of trans fatty acids and their serum levels and the risk of female breast cancer， we searched Pubmed， ISI Web of Science， ProQuest， Science Direct， CNKI， Wanfang， Weipu and other domestic and foreign databases. Literature selection， literature screening， data acquisition and quality assessment were conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Meta analysis of the included studies was performed using Stata 16.0 software. Results: Trans fatty acid intake was not associated with breast cancer risk in women (combined effect size: 0.99； 95%CI: 0.92-1.06； I2=66.9%， P=0)； the intake of conjugated linoleic acid was positively related to the risk of breast cancer (combined effect size: 1.09， 95%CI: 1.02-1.16， I2=0， P=0.597). In addition， serum levels of trans fatty acids were not associated with breast cancer risk in women (combined effect size: 0.94， 95%CI: 0.47-1.42； I2=85.3%， P=0).