Abstract:Cultured meat technology is a new type of food synthesis biotechnology that has emerged in recent years. Cultured meat is manufactured through producing and food processing artificial muscle and fat tissues by large-scale culture of animal cells. Compared with traditional farming methods， cultured meat technology shows greater advantages in environmental and resource protection， animal welfare， and public health. In this work， by searching and analyzing recently published papers in the cultured meat field， we summarize and outline the latest research progress and technical challenges from four major research directions including seed cell isolation and extraction， serum-free medium development， large-scale culture system， and three-dimensional culture and tissue shaping， and provide an outlook on the future key research directions of cultured meat technology. The development of efficient cultured meat manufacturing technologies and the establishment of large-scale production systems will provide strong support for the creation and application of new food protein resources.

Abstract:Cell cultured meat technology is a kind of disruptive technologies of food manufacturing emerging in recent years， which aims to establish a new mode of production and supply of meat protein for human beings. It will relieve the pressure of sustainable production and solve environmental protection problems in traditional animal husbandry. This article focuses on the development of scaffold materials and their tissue formation of cell cultured meats， summarizing the main technologies and methods related to texturized cultured meat based on scaffold from three aspects: cell perception and three-dimensional culture， biological culture scaffold materials screening and cell tissue formation construction. The research status and existing problems of cultured meat texture is analyzed， providing some references for the exploration and high-quality development of cultured meat technology.

Abstract:With the growth of global population， the contradiction between supply and demand of protein has become increasingly prominent. As the main animal protein supply mode at present， traditional animal husbandry has brought a series of global problems， such as greenhouse gas emissions， excessive consumption of resources， environmental pollution， zoonosis prevalence， animal welfare， etc.， while meeting market consumption. In view of the drawbacks of traditional animal husbandry， cell culture meat as a more clean， sustainable， fair and healthy new meat production mode has been paid more and more attention. This paper reviews the application of tissue engineering technology in the field of cell culture meat.

Abstract:Cultured meat is the use of animal cell culture to produce edible meat， which has many potential advantages such as animal welfare， potential high efficiency and so on. It is a future animal protein production technology. The core goal of cultured meat is to produce meat products with the same nutritional value and sensory properties as livestock raised meat. In recent years， the field of cultured meat has developed rapidly in key technologies. The production scale has gradually expanded and the production cost has been greatly reduced. This paper reviews the recent advances in the field of cultured meat， especially in vitro production of muscle， fat and connective tissue. In addition， large-scale production， safety evaluation and regulatory are also developing rapidly， which lays the foundation for the industrialization of meat production. This paper will provide reference for the large-scale production of cultured meat in China.

Abstract:The demand for protein is increasing， alternative protein has attracted global attention as advanced technology because it can effectively alleviate the problem of food crisis and environmental pollution. It is also urgent to be established and improved risk assessment and supervisory regulations of alternative protein products based on food safety considerations. The United States， European Union and Singapore are exploring the regulatory framework of alternative proteins. This paper discusses the possible food safety risks of alternative protein from the aspects of raw materials， production process and technology， such as external additives， production process and products； systematically reviews the main policy requirements and regulatory framework between China and foreign countries， and forecasts the future development trend. Finally， some suggestions are proposed for building safety evaluation， risk assessment and supervision of alternative protein products， and promoting the industrialization development in relevant fields.

Abstract:Objective: Construction of immortalized seed cells is an efficient and sustainable way to solve the problem of seed cells of cultured meat. Methods: Based on the current industrialized production of cultured meat， the source of seed cells needs to be solved urgently， and it is also a technical bottleneck in the large-scale production of cell-cultured meat. In this study， based on porcine myoblasts， the inducible vector was constructed by telomerase reverse transcriptase， and the cell induction was verified by immunofluorescence labeling， quantitative PCR， and karyotype analysis after nucleofection into the cells. Results: showed that: the construction of the immortalized cell induction vector had high sequence integrity and no mutation； the vector was successfully transferred into the cells and expressed efficiently， and one induction positive cell line was obtained； no uncontrollable mutation occurred in the chromosomal karyotype after transfection； The expression of telomerase reverse transcriptase in the cells was significantly higher than that in the control group； more importantly， the number of passages of induced positive cells exceeded the 'Hayflick＇ proliferation limit， achieving more than 200 passages. Conclusion: we constructed the immortalization-inducing carrier of porcine myoblasts， described the stability of cells after induction， which will have a broad application prospect in the production process of cultured meat.

Abstract:The sample solution was subjected to different conditions (25， 60， 80 and 100 ℃， for 30 min). Multiple spectroscopic techniques were used to characterize the interaction between gliadin and rutin and the emulsifying properties of the complex caused by temperature. The particle size， potential， thermal stability， emulsification activity and emulsification stability of the composite were determined to observe the changes in the functional properties of the composite under heat induction conditions. The results shown that proper temperature treatment (80 ℃) made a remarkable difference in the particle size [increased to (330.34±2.70)nm] and potential [increased to (19.30±0.67) mV] of the G-R solution， which can promote the unfolding of protein structure and improve the emulsification properties of the complex. The emulsification activity and emulsification stability of the complex after treatment at 80 ℃ were the highest， which were (105.71±0.86) m2/g and (85.94±2.92) min， respectively. This research provided new ideas for the functional modification and structural modification of gliadin.

Abstract:The interaction between homocatechol and bovine serum albumin(BSA) was studied. The results showed that homocatechol could quench the fluorescence of BSA. A macromolecular complex with weak fluorescence was spontaneously formed with BSA mainly through hydrophobic bond， and at least one binding site of homocatechol on BSA at 298， 310 K and 320 K. The binding constants of homocatechol to BSA were 5.908×102， 5.424×104， 1.535×106 L/mol. It is speculated that the quenching of BSA by homocatechol was mainly dynamic quenching， and there is also a static quenching process. The cold field emission scanning electron microscopy showed that 2 μmol/L homocatechol could promote the dissolution of protein and made its distribution more uniform. When the concentration of homocatechol was 2 μmol/L， the protein would aggregate. Molecular docking analysis showed that homocatechol was stably bound to the hydrophobic pocket of BSA Subdomain IIA (site I) mainly through hydrophobic bond， hydrogen bond and van der Waals force.

Abstract:In this study， the O/W emulsions have been generated by using β-conglycinin(7S) and glycinin(11S) as emulsifiers with adding Epigallocatechin gallate (EGCG). Three-dimensional fluorescence spectrum， thermal stability，particle size and ζ-potential of soy protein-EGCG complex， droplet size， chromatic aberration， droplet morphology and interfacial protein adsorption of the emulsion were determined in order to investigate the effects of EGCG interaction with 7S/11S proteins on emulsion stability. The results showed that EGCG decreased the fluorescence intensity of 7S/11S protein， resulting in an unfolding in soy protein tertiary structure and reducing thermal stability. EGCG caused the cross-linking of 7S/11S protein， increasing the particle size of its protein particles， and enhancing its ζ-potential to a certain extent. 11S protein was more sensitive to the above changes， suggesting that the interaction between 11S protein and EGCG was stronger than that of 7S protein. The addition of EGCG increased the a and b values of both protein emulsions， and significantly reduced the droplet size. When EGCG concentration was up to 0.02%， d4，3 of 7S/11S protein emulsion was the smallest， but 11S protein emulsion droplets still existed in the form of large aggregates. EGCG significantly improved the storage stratification of 7S protein emulsion， but had no significant effect on 11S protein emulsion. In addition， EGCG had no effect on the overall subunit distribution of 7S/11S protein emulsion interface proteins.

Abstract:The effects of whey protein (WP) and bovine serum albumin (BSA) on the thermal stability of betanin (Bt) at different temperatures were investigated. Fluorescence spectroscopy， circular dichroism， and Fourier transform infrared spectroscopy were used to study the interaction between WP/BSA and Bt. The results showed that WP and BSA inhibited the degradation of Bt content and the protection provided with WP was better than with BSA. Additionally， the change of pH also affected the thermal degradation of Bt. The half-life (t1/2) of the compound was the longest at pH 5.0， and the t1/2 of Bt-WP was up to 2.99 h. The fluorescence analysis showed that Bt led to a static quenching of WP/BSA. Further， the interaction was a spontaneous process with electrostatic interactions being the main force. Synchronous fluorescence spectra presented alterations in microenvironment of Trp and Tyr residues of WP/BSA， respectively， upon interaction with Bt. Circular dichroism and Fourier transform infrared spectroscopy analysis indicated that characteristic peak positions of amide I， II band and the secondary structures of WP/BSA was changed upon conjugation with Bt.

Abstract:The hypothetical surface protein LPL9_0968 in Lacticaseibacillus paracasei L9 was transcriptionally up-regulated 9.67-fold under bile salt stress. Through bioinformatics analysis， it was found that LPL9_0968 belongs to the surface protein of LiaX family， and the sequence similarity with LiaX protein in Enterococcus faecalis is as high as 61.96%， and there are multiple asparagine-glycine(NG) conserved sites in this family protein. Therefore， in this experiment， an inactivation mutant of the LPL9_0968 operon gene was constructed. Under 0.075% Ox-bile stress， the bile salt tolerance of the mutant was reduced by 10 times， indicating that the LiaX family protein is involved in the L9 bile salt stress resistance mechanism. Subsequently， the mutant strain exhibited strong sensitivity to glycine deoxycholate under single-component bile salt stress. Under the stress of 3.0% taurocholic acid， 0.4% taurodeoxycholic acid， 2.0% glycocholic acid， 0.075% glycodeoxycholic acid， the survival rate decreased by 1.95， 2.85， 2.05 times and 8.21 times， respectively. Furthermore， the results of Zeta potential experiment and scanning electron microscope showed that the cell membrane potential of the mutant strain increased under bile salt stress， and more severe atrophy appeared. Molecular docking showed that the surface protein interacted with different components of bile salt. Therefore， LPL9_0968 is likely to sense bile salt signaling molecules， regulate cell membrane surface proteins， and maintain the stability of cell membranes to improve the bile salt resistance of strains. This experiment explored the function of the surface proteins of the LiaX family in lactic acid bacteria for the first time， proved its importance in the bile salt stress resistance of the strain， and laid a theoretical foundation for the in-depth study of its anti-bile salt mechanism.

Abstract:The hydroxyl radical oxidation system (0.01 mmol/L FeCl3， 0.1 mmol/L ascorbic acid， H2O₂) was employed in this study to investigate the effects of H2O₂ concentration (0， 10， 30， 50， 70 mmol/L) on the oxidation and nitrosation of pork myofibrillar protein (MP). Results showed that with the increase of H2O₂ concentration， the protein carbonyl content， disulfide bond level， dityrosine， 3-nitrotyrosine (3-NT)， N-nitrosodiethylamine (NDEA) and N-nitrosodimethylamine (NDMA) content were increased， while the contents of total sulfhydryl groups， free amino groups and the residual amount of NaNO₂ were decreased. The relationship between indexes of protein oxidation and nitrosation was assessed by pearson correlation coefficient. N-nitrosamine and 3-NT content within MP significantly positively correlated with carbonyl， disulfide bond and dityrosine content (P<0.05)， but negatively correlated with total sulfhydryl groups and free amino groups (P<0.05). These results indicated that 3-NT may be a potential marker of protein oxidation and nitrosation. Our results demonstrated that protein oxidation could promote protein nitrosation and consequent NDMA and NDEA formation. Therefore， protein oxidation and nitrosation should be controlled during meat processing and storage to control the formation of N-nitrosamine.

Abstract:This paper aims to explore the effect of aroniamelanocarpa juice on improving constipation and maintaining intestinal health in mice. The mice were divided into five groups: blank control group， constipation model control group and low， medium and high dose group of aroniamelanocarpa juice. After 14 days of sample intervention， the constipation model was established by loperamide hydrochloride. The defecation function index， intestinal motility index， gastrointestinal regulatory peptide index and 16S rRNA intestinal flora index of mice in each group were measured. The results showed that the constipation model was established. Aroniamelanocarpa juice could shorten the discharge time of the first black stool， increase the number and quality of defecation granules within 5 hours， improve the propulsion rate of small intestinal ink， promote the contents of gastrin (Gas)， motilin (MTL) and substance P (SP)， reduce the contents of somatostatin (SS)， endothelin (ET-1) and vasoactive intestinal peptide (VIP)， the effect has a certain dose correlation. In addition， aroniamelanocarpa juice can change the distribution of intestinal flora and enrich the abundance of species to a certain extent， significantly reduce the relative abundance ratio of Firmicutes and Bacteroidota(F/B)， reduce the abundance of Proteobacteria and Staphylococcus in constipated mice. Therefore， the study provides that aronia melanocarpa juice had a defecation effect on mice with constipation induced by loperamide hydrochloride， and its mechanism may be to improve the symptoms of constipation by regulating the secretion of intestinal hormones and the structure of intestinal flora.

Abstract:To investigate the impact of different fresh fruits preloads on acute postprandial glycemic and satiety responses， 10 young overweight volunteers consumed apple， orange or pear preload containing 15 g available carbohydrates before a rice meal containing 50 g available carbohydrates. The postprandial blood glucose and satiety parameters in 180 min as well as the texture properties and chemical composition of the three fruits were measured. The results indicated that all fruit preloads decreased the maximum amplitudes of glycemic excursion significantly compared with the control group. Apple and orange preload achieved 27.3% and 34.1% reduction of the area under glycemic curve contributed by per gram of available carbohydrate. The self-reported satiety scores did not differ significantly among test meals and the control meal. In conclusion， this study demonstrated that preloading of 3 fruits 30 min before white rice meal could mitigate postprandial glycemic response in young overweight subjects， while the effect might partly be explained by the composition and texture characteristics of fruits.

Abstract:10-Hydroxy-12-octadecenoic acid(10-HOE)， one microbial hydroxy unsaturated fatty acid， was recently reported to have the bioactivities of the anti-fungi， anti-inflammatory， and anti-allergic effects. It has the potential to be used in food， pharmaceutical， chemical， and other industries. Thus， the biosynthesis of 10-HOE is worthy of investigation. In this work， 10-HOE was biosynthesized using the resting cell system with linoleic acid as the substrate and the recombinant Escherichia coli as the catalyst. After the single-factor experiment， the optimum conditions for the 10-HOE biosynthesis using resting cells were obtained， eg. 0.25 mmol/L flavin adenine dinucleotide (FAD)， 2% hexane， 15 mmol/L sodium chloride， 20 g/L linoleic acid， and 200 g/L cells at pH 7.0. The mixture was incubated at 37 °C and 200 r/min after a thorough mixing with a vortex mixer， and a conversion yield of (73.1±0.9)% with the 10-HOE concentration of (16.3±0.2) g/L was achieved at 24 h. Within our knowledge， this is the highest concentration for the10-HOE biosynthesis. This work provided one method of the 10-HOE biosynthesis， which might be helpful for the industrial production.

Abstract:Using natural corn starch as raw material， the high pressure porous starch was prepared by the combination of high static pressure， α-amylase and saccharase. The porous starch was cross-linked with sodium trimetaphosphate and optimized. The structure and physicochemical properties of the cross-linked porous starch were studied. The results show that when the pressure is 200 MPa， both the high pressure porous starch and the high pressure cross-linked porous starch have good porous starch morphology， the high pressure cross-linked porous starch particle pore structure is more uniform， the specific surface area and pore size are increased obviously， the short-range ordered structure is destroyed， the crystallinity is reduced， and at the same time. The porous structure of high pressure cross-linked porous starch improved the adsorption， and the oil absorption and water absorption increased from 68% and 120% to 75% and 124%， respectively. The optimum conditions for preparation of porous starch were determined as follows: temperature 40 ℃， reaction pH 11， dosage of crosslinking agent 3% of starch base， pressure 200 MPa， and deposition volume measured in single factor and orthogonal experiments. The light transmittance of high pressure cross-linked porous starch prepared by this process decreased by 3.26% and 5.06%， respectively， compared with that of porous starch and high pressure porous starch. Compared with porous starch and high pressure porous starch， the water separation rate decreased by 24.7% and 28.5%， respectively. The solubility and swelling degree of porous starch formed under different treatment conditions are significantly higher than that of original starch， which is beneficial to the application of porous starch.

Abstract:Fat plays a key role in maintaining the good quality of salad sauces， and its variation affects the texture properties of salad sauces. Rubbing test is a common method used to evaluate some of the texture properties of food products. In order to investigate the effect of fat content on the smoothness of salad sauces， particle size measurements and texture profile analysis (TPA) was performed for commercial salad sauces with different fat contents， and then the friction properties were investigated using the rubbing substrates constructed by polydimethylsiloxane (PDMS) and simulated saliva. The results showed that the particle size of salad sauces increased with the decrease of fat content， which was significantly correlated with their coefficients of friction (P < 0.05). But there was no significant correlation between their TPA parameters and coefficients of friction. Under the effect of saliva， the average coefficient of friction of high-fat salad sauces was significantly lower than that of low-fat salad sauces， and coefficients of friction functioned as a linearly decreasing relation with the increasing fat content. Reasonably setting parameters was more favorable to characterize the difference in the smooth levels of salad sauces. This study can provide a better insight into the development of low-fat salad sauces and other similar health foods.

Abstract:The objective of this study was to explore and compare the effect of different thermal treatments on the stability of koumiss proteins. It measured indicators of koumiss quality at different heat treatment conditions， and then the suspension stability of koumiss protein as well as the denaturation degree of whey protein were observed by SDS-PAGE. Fourier transform infrared spectroscopy was employed to investigate the variation of secondary structures. The results showed that thermal treatment from 65 ℃ to 90 ℃ had no effect on the acidity and pH value of koumiss， but the centrifugal suspension content， denaturation rate and the proportion of secondary structures of koumiss protein after heat treatment changed significantly compared with those without heat treatment (P<0.05). The variation of β-sheet played an important role in the degree of thermal aggregate of koumiss protein. With the increase of the degree of thermal treatment， the viscosity of koumiss and the degree of denaturation of whey protein increased continuously， and the denaturation rates were 38.52%， 40.88%， 50.94% and 69.03% respectively， which showed an accelerated increasing trend. After heat treatment at 90 ℃ for 5 min β-Lactoglobulin disappeared and the stability of whey protein was seriously damaged. Moreover， the properties of zeta-potential， protein suspension stability and β-sheet structure showed a trend that increased firstly and then decreased. Appropriate thermal treatment could improve the stability of koumiss proteins.

Abstract:The volatile components extraction method is critical for the analysis of aroma components of Wuyi Rougui tea. In this study， the volatiles of Wuyi Rougui tea infusion were first extracted by two commonly used extraction methods， namely， headspace-solid-phase microextraction (HS-SPME) and simultaneous distillation extraction (SDE)，and then qualitatively and quantitatively analyzed by GC-MS. The extraction conditions of HS-SPME were optimized and the optimal conditions were as follows: 50/30 μm DVB/CAR/PDMS fibers， 50 ℃ extraction temperature， 50 min extraction time，30% NaCl addition. With this optimal condition， a total of 84 volatile compounds were extracted by HS-SPME， and 40 volatile compounds were extracted by SDE. Of these volatiles， 26 components were detected by both methods. Both extraction methods demonstrated comparable extraction efficiency for esters. HS-SPME showed better extraction efficiency for heterocyclic volatile compounds， aliphatic alcohols with medium to low boiling point， alkanes and ketones， whereas SDE showed better extraction efficiency for alcohols， acids， and phenols of high volatility. The conclusion is thatthe combination of HS-SPME and SDE methods should be used to analyze the aroma components of Rougui tea.

Abstract:The anthocyanins and polyphenols in Sorbus melanocarpa are the highest in known plants， and have a variety of health-care functions. However， due to the poor stability and low bioavailability of anthocyanins， their application in various industries is limited. In this study， chitosan and polyglutamic acid were used to encapsulate the anthocyanin of Sorbus melanocarpa by ion gel method under pH drive to improve the stability of anthocyanin of Sorbus melanocarpa. On the basis of single factor experiments， three significant factors were selected to conduct response surface optimization experiments with the embedding rate as an indicator， the best preparation conditions for obtaining Sorbus melanocarpa nano-microcapsules are: 36 mg of anthocyanins， 1.3 mg/mL of chitosan， 60 minutes of mixing time， and mass ratio of chitosan: polyglutamic acid 2∶1， pH 4.5， the obtained Sorbus melanocarpa anthocyanin nano-microcapsules have an embedding rate of 59.54%， a particle size of 317.5 nm， and a Zeta potential of 36.7 mV， Observed by scanning electron microscope， the anthocyanin nanocapsules of Sorbus melanocarpa are smooth and oval in appearance. This indicates that the anthocyanin nanocapsules of Sorbus melanocarpa have good structure and stability， which is beneficial to expand its application range in the food industry.

Abstract:Postharvest 'Ziniangxi' litchi fruit were used as experimental materials and dipped in 0.5 mmol/L melatonin (MT) solution for 10 min. After drying， the fruit was refrigerated at (4 ± 1) °C and (85 ± 5)% relative humidity for 30 d. During refrigeration， the effects of MT treatment on the chilling injury (CI) and its related physiological metabolism in litchi were investigated. The results showed that MT treatment reduced the chilling injury index and delayed the decrease in the chromaticity a* value in cold-stored litchi fruit. The CI index in MT-treated fruit was 49.4% lower than that in control fruit at 30 d， while chromaticity a* value in MT-treated fruit was 37.2 % on average higher than that in control fruit from 10 to 30 d of refrigeration. MT treatment significantly inhibited the increases in membrane relative conductivity while suppressing the accumulations of malondialdehyde (MDA)， superoxide anion (O₂·-) and hydrogen peroxide (H2O₂)， as shown by the decreases of 29.6%， 16.9%， 6.9% and 6.3% in relative conductivity， MDA content， O₂·- production rate and H2O₂ content in MT-treated fruit at 30 d， respectively， thus contributing to mitigation of oxidative stress and maintenance of membrane integrity. MT reduced the activities of polyphenol oxidase (PPO) and peroxidase (POD) as well as inhibited the decreases in total phenolics， flavonoids and anthocyanins contents in cold-stored litchi fruit， thereby ameliorating enzymatic browning. MT treatment significantly enhanced the activities of superoxide dismutase (SOD)， catalase(CAT)， ascorbate peroxidase(APX)， monodehydroascorbate reductase (MDHAR)， dehydroascorbate reductase (DHAR) and glutathione reductase (GR)， and maintained higher levels of ascorbic acid (AsA) and reduced glutathione (GSH) contents and the higher ratios of AsA/ dehydroascorbic acid (DHA) and GSH/ oxidizided glutathione (GSSG) when compared to control fruit， which could lead to increases in antioxidant activity in litchi fruit during cold storage. In addition， MT treatment up-regulated the expression abundance of LcMsrA1， LcMsrA2， LcMsrB1 and LcMsrB2 during cold storage， thereby promoting the improvement in repair capacity of oxidized protein. The results indicate that exogenous MT treatment could alleviate the CI occurrence in cold-stored litchi fruit by modulating the chilling tolerance-related physiological metabolisms.

Abstract:This study was design to clarify the important transduction role of Ca2+ in meat tenderness development of Tan sheep during postmortem storage. Results indicated that the shear force decreased significantly before 96 h， and then increased significantly from 96-192 h. Mitochondrial Ca2+ levels increased significantly before 96 h， and decreased significantly after 96 h. The activity of calpain-1 decreased significantly with increasing time postmortem. The activity of caspase-3 increased significantly before 96 h and then decreased significantly. Correlation analysis indicated that the shear force was positively correlated with mitochondrial Ca2+ levels， and significant positively correlated with activity of caspase-3， significant negatively correlated with activity of calpain-1. 0-96 h， 5 up-regulated differentially abundant proteins and 2 down-regulated differentially abundant proteins were enriched in Ca2+ signaling pathway. 96-192 h， 2 down-regulated differentially abundant proteins were enriched in Ca2+ signaling pathway. 0-96 h， 30 differentially abundant proteins were enriched in apoptosis signal transduction pathways. 96-192 h， 15 differentially abundant proteins were enriched in apoptosis signal transduction pathways. The energy from hydrolysis of ATP was used by SERCA to drive Ca2+ transport across membranes. Increasing of VDAC likely provided channels for Ca2+ lead to mitochondrial Ca2+ overloading and mitochondrial dysfunction. Meanwhile， increasing of VDAC could be related to the increase of CYTC in cytoplasm， thereby caused the cascade of apoptosis， and activated caspase-3 to hydrolyze structural proteins， finally influence tenderness of Tan sheep meat. In addition， the decrease of actin was caused by Ca2+， and provided the contractile mechanism of muscle tissue， thus affecting the tenderness of meat. The conclusion of this study further confirmed the important signal transduction role of Ca2+ in the development of meat tenderness during postmortem storage.

Abstract:In order to study the quality change of live Crassostrea gigas after post-harvesting， the simulated storage and transportation process of the transport chain of ‘waterless transport- re-immersed treatment - air exposure storage selling’ was set up. The shelf quality of live oyster was evaluated by three indexes including vitality， taste characteristic and microorganism. The experimental results showed that ① Vitality: after 1 day of waterless transportation， oyster weight， pH and SDH activity decreased significantly from 187.08 g， 6.78 and 7.92 mg/g to 183.39 g， 6.56 and 5.84 mg/g， respectively. After reimmersion by the artificial seawater， it quickly recovered to the initial state. Glycogen content and pH gradually decreased in the later air exposure storage process， but AEC value remained at about 40.00% all the time， and significantly decreased to 26.26% on the 10 th day of air exposure storage. ② Taste characteristics: taurine and glutamic acid contents were higher in the whole software， which were 2.76 mg/g and 1.05 mg/g， respectively， followed by aspartic acid and alanine， which were 0.43 mg/g and 0.49 mg/g， respectively. Only the TAV value of glutamate was >1， which was an important compound affecting the flavor of Crassostrea gigas. The content of glutamate in the simulated circulation was stable and did not fluctuate greatly. ③ Microorganism: The total number of bacteria increased significantly after 1 day of waterless transportation， but did not change significantly after re-immersion， and gradually increased in the later air exposure storage process. However， the total number of bacteria on the 10th day was 104/g， which was still within the edible 107/g range. High-throughput sequencing showed that the microbial community structure at the later stage of the simulated circulation process was dominated by Pseudoalteromonas and Shewanella， which may play an important role in the process of oyster spoilage. Therefore， the initial quality of Crassostrea gigas could be maintained under the mode of ‘1 d waterless transportation - re-immersed - air exposure storage selling 8 d’.

Abstract:In this study， the flavedo of 23 Citrus varieties were selected as materials， and the components and antioxidant capacity of flavonoids were investigated by Liquid Chromatography-Mass spectrometry(LC-MS). The results showed that， the total phenolic content of the flavedo varied from 4.38 mg GAE/g DW to 21.10 mg GAE/g DW； and the varieties with the strongest and weakest comprehensive antioxidant capacity in the flavedo were 'local early' and 'Aiyuan 38'. Using the LC-MS to identify the flavonoids in the flavedo of 23 Citrus varieties， we identified a total of 53 flavonoids， including 5 flavonoid-C-glycoside， 4 flavonoid-O-glycoside， 12 flavanone-O-glycoside， 32 polymethoxyflavone (PMFs). Compared with the existing literature， two flavonoids， phloretin-3'，5'-di-C-glucosid and hesperitin-7-O-rhamonoside， were reported for the first time in Citrus. The main flavanones contained in the flavedo are eriocitrin， neoeriocitrin， narirutin， hesperidin， and didymin. The main PMFs in the flavedo are nobiletin， tangeretin， 5HPMF and sinensetin. In conclusion， this article further supplemented information on the components and antioxidant activities of different Citrus varieties， which provided scientific guidance for Citrus consumption and set a theoretical basis for bioactivity studies.

Abstract:Objective: Naturally fermented cow milk is an important part of the daily diet of nomadic people in Tajikistan， which contains rich resources of lactic acid bacteria. However， there are few studies on the microbial community structure and biodiversity of lactic acid bacteria in natural fermented cow milk in Tajikistan. Methods: In this study， pure culture method combined with metagenome sequencing technology was used to study the microbial diversity of naturally fermented cow milk in Tajikistan. At the same time， the microbial community data sets in Tajikistan were compared with another two regions in Kyrgyzstan and Morocco. Result: The results of isolation and identification showed that 92 strains of lactic acid bacteria were isolated from 7 naturally fermented cow milk samples， and the dominant strain was Lactobacillus delbrueckii. The results of sequencing showed that Lactobacillus delbrueckii was the dominant strain with a relative content of 82%. The comparative analysis of the three regions showed that the microbial community in naturally fermented milk had some differences. The composition of bacteria in Tajikistan and Kyrgyzstan was similar， while Morocco was quite different from them. Conclusion: Through this study， we acquired lactic acid bacteria resources and the information of diversity of naturally fermented milk in Tajikistan， provided strains for the development and utilization of lactic acid bacteria， and provided basic data for the research of lactic acid bacteria in naturally fermented dairy products.

Abstract:Microbial populations in the brewing of soy sauce are abundant， diverse and complex. The aim of this study was to gain a better understanding of global microbial diversity during the soy sauce fermentation process. Succession and spatial heterogeneity of microbial community in soy sauce production were analyzed by high-throughput sequencing at the stages of koji-making， mash fermentation and sauce extraction. The results showed that the microbiota diversity， community composition， and functional properties of microbial community in soy sauce fermentation exhibited distinct stages and spatial heterogeneity. In the analysis of alpha and beta diversity， the bacteria diversity were higher than that of fungi. The microbiota exhibited a higher biodiversity in the stages of mash fermentation and sauce extraction than in the koji-making. The mash from the upper layer exhibited high bacterial diversity and the lower layer exhibited high fungal diversity. In the analysis of community composition， there were 147 bacterial genera and 19 fungal genera by amplicon sequencing during the soy sauce production. Staphylococcus， Weissella， and Tetragenococcus were the core bacterial genera. Aspergillus and Zygosaccharomyces were the core fungal genera. Each microorganism showed abundance differences in time and space. In the analysis of functional predication， the major bacterial function was amino acid metabolism， and the major fungal functions were carbohydrate and fat metabolism. Conclusively， this study revealed the effects of fermentation time and space on microbial community during the fermentation process of soy sauce， and provided basic data for the further study of microbiome quality control， regulation of community composition， and optimization of process conditions in soy sauce brewing.

Abstract:On the market， there is a non-standardized phenomenon of adding mutton tallow into the beef tallow to pretend to be pure beef tallow， and there is no effective method to distinguish beef tallow and mutton tallow now. In this study， beef tallow and mutton tallow were differentiated by aroma difference. The aroma of 9 beef split tallow， 6 beef kidney tallow and 5 mutton tallow were analyzed and compared using electronic nose technology and gas chromatograph-olfactometry-mass spectrometer (GC-O-MS). The results of electronic nose combined with linear discriminant analysis(LDA) showed that beef kidney tallow， beef spilt tallow and mutton tallow could be separated into three classes. A total of 39 aroma compounds， including alcohols， esters， ketones， acids， aldehydes， and other compounds， were identified by GC-O-MS. Orthogonal partial least-squares discrimination analysis(OPLS-DA) showed that beef kidney tallow， beef spilt tallow and mutton tallow could be distinguished by their aroma. This study can provide reference for the flavor quality control and the establishment of market standard of beef tallow.

Abstract:This paper presented an analysis method of TFAs in hydrogenated soybean oil based on THz spectroscopy. The THz time domain spectrum of hydrogenated soybean oil was transformed into frequency domain spectrum by Fourier transform， and the refractive index and absorption spectra were calculated by using the optical parameters. In order to study the absorption characteristics of TFAs in hydrogenated soybean oil in terahertz band， the RB3LYP in DFT and 6-311G (d， p) were adopted for optimizing the geometric configuration and calculating vibration frequency of the several major trans oleic acids and trans linoleic acids in hydrogenated soybean oil. These studies laid a theoretical basis for the composition and qualitative analysis of TFAs in hydrogenated soybean oil. The prediction model of TFAs content in hydrogenated soybean oil was established by LS-SVR， and compared with PLS and SVR models. The prediction results demonstrated that the LS-SVR model was the best one. The RMSEP was 0.3246， the determination coefficient R2 was 0.9792， and the RSD was 3.81%， which could meet the actual detection requirements. Then， PSO algorithm was used to optimize the parameters of LS-SVR model， and compared with GS and GA optimization methods， the optimal parameter combination was selected. The RMSEP， R2 and RSD of the optimized LS-SVR model were 0.0763， 0.9989 and 0.90%， respectively， which significantly improved the prediction accuracy. This study laid a foundation for the rapid detection of TFAs in hydrogenated soybean oil by terahertz spectroscopy.

Abstract:In order to explore the effect of Dendobium stem addition on microbial community structure and volatile flavor substances of Xiaoqu, the microbial community structure composition and volatile flavor compounds in traditional Xiaoqu (DZ) and three kinds of Xiaoqu (A, B and C) with different Dendrobium stem addition were analyzed by high-through-put sequencing technology, headspace solid- -phase microextraction and gas chromatography - -mass spectromety, respective-ly. The results showed significant differences in microbial communities and flavor substances compared DZ with AB and C. At the genus level, the dominant bacteria genera of DZ were uncultured_ _bacterium_ o_ Chloroplast . .ncultured _bacteri-um. f Mitochondria and Lac tobacillus. And the dominant fungi genera were Rhizopus and Aspergillus. The dominant bac-teria genera of A,B and C was Bacillus, and the dominant fungi genera were Rhizopus, Aspergillus and Wicker-hamomyces. Meanwhile, the relative abundance of Bacillus, Rhizopus and Wic kerhamomyces inereased with the addition of Dendrobium stem as well. However, the addition amount of 50% was not conducive to the growth of beneficial mi-croorganisms. A total of 41 volatile flavor substances were identified in Xiaoqu samples, and 16 important significantly different metabolites were selected (VIP> 1.0,P< 0.05). Among them, A (13 kinds), B (15 kinds),C (10 kinds) and DZ (2 kinds) were selected, respectively. Orthogonal partial least squares discriminant analysis showed that there was a slight differences between A，B and C, DZ. In addition, the corelation analysis showed that there was a certain corre-lation between the dominant microorganism and physical and chemical properties， and had a positive correlation with al-cohols, phenols, aldehydes and ketones, also. It was found that the quality of Xiaoqu was better when 30% Dendrobium stem was added, which provided a theoretical basis for the functional application of Dendrobium Xiaoqu.

Abstract:In order to identify the geographical origin of Eriocheir sinensis under the co-cropping mode of Northern Rice crab， the 16 elements of V， Cr， Mn and other 16 elements in 36 samples of Eriocheir sinensis in Heilongjiang， Jilin and Liaoning province were quantitatively detected by ICP-MS， and the data were analyzed. The results showed that the contents of V， Cr， Ni， Mn， Zn， Ba， Fe， Mo， Cd， As， Pb and U in the samples of Eriocheir sinensis were significantly different (P < 0.05). Most of the elements showed a very significant correlation. Based on the mineral element content characteristics， the origin of Eriocheir sinensis samples in different provinces was determined by PCA， OPLS-DA and S-LDA. The results showed that PCA could only distinguish some samples， while the initial discrimination accuracy of OPLS-DA and S-LDA methods is 100%， the prediction ability of OPLS-DA was 71.4%， and the accuracy of S-LDA was 97.2%， which was the best method. The contents of Zn， Cr and Pb were important variables for tracing the samples of Eriocheir sinensis in three provinces. The results showed that the effective identification of the origin of Eriocheir sinensis under the co -cropping mode of rice crab in Northeast China can be realized based on the combination of element fingerprint and chemometrics analysis.

Abstract:Objective: In order to quickly detect the mechanism of β-lactam antibiotic resistance carried by food-borne pathogens in a series of foods， the qualitative standard samples of Salmonella reference strain carrying β-lactam antibiotic resistance coding genes were developed. It will provide the technical support of strong traceability， high evaluation accuracy and be conductive to widely carry out the detection of drug-resistant microorganisms among various testing institutions. Methods: Salmonella isolated previously and stored at -80 ℃ were subcultured on LB agar plate. 3 Salmonella representatives were selected and the encoding genes of β-lactam antibiotic resistance carried by the 3 strains were verified via PCR amplification， DNA sequencing and BLAST. The genetic stability of the target genes was simultaneously identified. The standard samples of the reference strain with live bacteria amount of 106～107 CFU/vial were prepared by vacuum freeze-drying technique. On the basis of GB/T 15000.3-2008， the three reference strains were tested for homogeneity， the results were statistically analyzed via F test to evaluate their uniformity. The prepared reference strains were stored at 37 ℃， 4 ℃ and -80 ℃ simulated， respectively， to test their transport stability and storage stability. Seven laboratories with checkout qualifications were commissioned to jointly evaluate the reference strains' characteristic values. Results: The β-lactam antibiotic resistance mechanism associated encoding genes of blaCTX-M-55/ blaTEM-1 in one Salmonella， of blaTEM-1/blaOXA-1/blaCTX-M-l5 in one Salmonella， and of blaCTX-M-3 in one Salmonella can stably inherit in 15 generations. The homogeneity of the prepared reference strains meets the necessary requirements. When stored at 37 ℃ for 13 d， 4 ℃ for 90 d and -80 for 360 d， the viable bacteria amount was basically stable and above ×104 CFU/ vial. The characteristic values of the reference strains were consistent with 7 laboratories' and indicated that the prepared strains could be used as the standard samples. Conclusions: In accordance with the standard sample preparation standards and specifications， three reference strains carrying β-lactam antibiotic resistance encoding genes were developed. They meet the requirements of standard samples and can be used for rapid detection of β-lactam antibiotic resistance mechanism of food-borne bacterial.

Abstract:Food testing data is an important tool for food risk analysis. The final data matrix is missing due to different testing items for similar foods， and most of the existing food testing data is undetected. Through the introduction of TF-IDF (The term frequency-inverse document frequency) weight determination method has constructed a new type of food risk analysis model. This paper uses the sampling information of vegetable samples of edible agricultural products in a city from 2019 to 2020 as the research data， and calculates the risk index of each sample in the vegetable through the model. The results show that among the vegetable products tested from 2019 to 2020， the high-risk index is leeks and celery， and the over-standard index is chlorpyrifos， which needs to be paid more attention in supervision， while most of the remaining vegetables are low-risk. Compared with other traditional analysis methods， this analysis model can give a specific risk index， is intuitive in evaluation， and shows better evaluation performance in big data analysis. At the same time， this model sets weights in an objective and universal mode， which eliminates the influence of subjective factors in the evaluation and further enhances the practicability in diversified data analysis. The model is established in the context of the era of big data， and provides a new way of thinking for further in-depth research and exploration of new paths for food safety risks and evaluation methods.

Abstract:Liposomes are a kind of carrier with a nanostructure formed by encapsulating substances in the lipid bilayer， which has become a research hotspot in recent years due to the variability of components and superior structural characteristics. Liposomes can form biomembranes similar to bimolecular vesicles on the surface of active substances， improving the stability and bioavailability of active ingredients. Therefore， liposomes have extensive applications in the food industry. This paper reviews the preparation technology of liposomes and its application and research progress in the food industry.

Abstract:The CRISPR system is an emerging gene editing technology. It is an immune response system that exists in some bacteria. It uses the protein encoded by the Cas gene to efficiently recognize and cut the foreign DNA that enters the cell， protecting the bacteria themselves from Exogenous gene infringement. The CRISPR system is mainly used for targeted knock-in and knock-out of genes. The system has the advantages of simple operation and wide application range， and has been widely used in various microorganisms， animals and plants. Among CRISPR systems， type II CRISPR system is the most widely used system and is currently a research hotspot. It includes CRISPR/Cas9， CRISPRa and CRISPRi technologies. Since CRISPRa technology is currently less used， this article reviews the current research status of CRISPR/Cas9 and CRISPRi technologies in microorganisms， and prospects the future development of the two technologies.

Abstract:The natural antibacterial substance of bacteriocin produced by lactic acid bacteria is an ideal substitute for chemical preservatives and antibiotics. Cell communication triggers various life activities via signal transmission. In this paper， the cell communication mechanism for producing bacteriocin was described from the aspects including the sources of different inducing signals， the induction mechanism of different signals， the mechanism of bacteriocin synthesis， the multi-cell communication in co-cultivation， and the signal network of quorum sensing (QS) in complex environment. And the research progress on the cell communication mechanism of LAB was systemically introduced. These will provide important reference for promoting the research and application of LAB bacteriocins.

Abstract:Chinese traditional fermented vegetables are favored by consumers because of their unique flavor， rich nutrition， and high appetite. During the fermentation process， bacteria and fungi formed a complex and changeable colony structure and characteristic flavor of Chinese traditional fermented vegetables through different metabolic pathways. This work overviews the flavor profiles of Chinese traditional fermented vegetables (e.g. Paocai， salted vegetables， and Jiangcai)， the core microbial structure， and their correlation. The outcome could provide the theoretical basis for high quality development of Chinese traditional fermented vegetable industry.

Abstract:Recent studies have shown that diet could affect the inflammatory bowel disease (IBD) and cereals are an indispensable part of people's daily diet. Intake of grains can reduce the risk of IBD and colorectal cancer. This is because the dietary fiber， phytochemical and amino acids in grains can repair mucosal barriers， remove free radicals， reduce inflammation， fight cancer， and regulate gut microbiota composition. However， the gliadin and amylase-trypsin inhibitor contained in wheat grains the gliadin and amylase-trypsin inhibitors contained in wheat grains also have the risk of aggravating IBD， indicating that the intake of grains is a double-edged sword for IBD. This article focuses on grains and summarizes the effects of grains and their components on IBD.

Abstract:Health foods are foods that claim to have specific health functions or are for the purpose of supplementing vitamins and minerals. The positioning， requirements， and names of such products vary globally. China's ‘Food Safety Law’ clearly stipulates that health food claims for health functions should have a scientific basis and must not cause acute， subacute or chronic harm to the human body. The Regulations for the Implementation of the Food Safety Law stipulate that foods other than health foods shall not be claimed to have health functions. This article focuses on the management of functional claims of similar products in health foods. Based on the systematic review of the practices in the United States， the European Union， Canada， South Korea and other countries and regions， this article summarizes the current status and characteristics of the management of health foods in China， and put forward suggestions for perfecting the claims of common food and health foods in China.

Abstract:Erythritol， as a kind of sweetener， has received much attention from the market and industry due to an increasing demand of healthy diet and reduced or low sugar intake. The consensus was carried out with literature searches and symposiums. On the basis of comprehensive analysis of the previous researches and applications of erythritol， the scientific consensus of erythritol is formed by combining the opinions of relevant experts in the scientific and industrial circles such as food additives and food science. Erythritol is a kind of four-carbon polyol and it is widely distributed in nature， with characteristics included low-calorie and high-tolerance， etc. At present， industrial production of erythritol is mainly adopted by microbial fermentation， and its safety as food additive has been recognized by authoritative institutions at home and abroad. However， more researches on its production and application are still necessary， and promote scientific cognition. The consensus will take an important role in terms of guiding industrial scientific understanding， enterprises standardizing use and public reasonable consumption for erythritol， and thus help to promote the healthy and innovative development of erythritol-related food industries.

Abstract:Breast milk research， which is the focus of maternal and infant health research， is the golden key to unlocking the mysteries of early life nutrition. The purpose of this paper is to focus on the research trends of breast milk science and infant formula manufacturing technology， and to clarify the innovative direction of maternal and infant nutrition research in China. Based on the analysis of literature and industrial research， top six research topics was illustrated， including nutritional needs of early life， depth exploration of milk composition， effects assessment of breast milk， innovative manufacturing of functional raw materials， testing technology and evaluation methods of raw materials， efficient retention of active ingredient， covering the maternal and child nutrition scientific research， functional material research and infant formula manufacturing technology， thus providing important reference for scientific research of breast milk and development of infant formula industrial.