Abstract:Sarcopenia is an age-related decline in muscle mass， strength， and physical performance. The only way to slow down or delay its occurrence and development is through exercise nutrition intervention. Due to the difficulty of dietary nutrition supplement caused by the decline of digestive and absorption function in the elderly， the use of special nutrients will become an indispensable and effective way. In this paper， the supplements including protein， amino acid， vitamin D， calcium， antioxidants， adaptogenic herbal and other nutrients for the prevention and treatment of sarcopenia in the elderly were described in detail.

Abstract:Furan， a typical food contaminant generated during the heating of foods， is harmful to the health. In this study， we discussed the antioxidant activity of naringin and its effects on furan-induced toxicity. Fifty male Balb/c mice were randomly divided into five groups（control group， furan-treated group and three naringin-treated groups with the concentration of 5， 10， 20 mg/kg/d， respectively）. Protective effects of naringin on furan-induced toxicity were evaluated by determining the ROS content， oxidative damage， cytokine levels， DNA damage， and the liver and kidney damage in a mouse model. The results showed that furan induced the kidney and liver of mice different degrees of damage. Compared with the furan-treated group， naringin mitigated the oxidative damage induced by furan by increasing GST， GSH and SOD activities but decreasing MPO and MDA content. On the other hand， naringin could decrease cytokine levels of IL-1β， IL-6， IL-10 and TNF-α in the serum of furan treated mice. At the same time， naringin could decrease the ROS content， 8-OHdG， the liver and kidney damage indexes of AST， ALT， LDH， BUN and creatinine. Conclusion： naringin， as a kind of antioxidant， has a certain protective effects on the liver and kidney injury of the mice induced by furan， while 10 mg/kg/d of naringin-treated group was the most obviously concentration on furan induced toxicity.

Abstract:In this experiment， five kinds of soy protein isolate as raw materials， using a variety of protein analysis and detection methods， study in structure changes of in vitro digestion process soy protein isolate. Fitting FT-IR and Raman spectroscopy result of soy protein isolate and digestion products showed that the changes of content of the secondary structural elements were basically the same， a negative correlation was found between DH and α-helix， β-sheet content. Tyrosine residues of soybean protein isolate and digestion products tend to be“exposed”. The increasing λmax with digestive time and decreased Raman band intensity of tryptophan suggested that tryptophan residues tend to hydrophilic microenvironment. Five different varieties of soy protein isolate after 5 h of continuous digestion in vitro experiments， the degree of hydrolysis increases with time， but after 1h after digestion， the growth rate of DH slowed down and under the same conditions， DH differences between different samples.

Abstract:This research construct the soil metagenomic library， which have 1.3×104 storage capacity and 30 Mb length of the total gene. Screening the positive clone can hydrolyze xylan from the library based on the functional strategy. Sequence analysis revealed that cbxynA potential encoding xylanase gene with 822 bp length. Only 45% of its amino acid sequence similar with the encoding xylanase from Halobacteriaceae archaeon（Archaea）， which indicated that it’s a novel unknown sequence. Molecular weight of cbxynA expressed in the E.coli was 29 ku consistented with predicted size. At the same time， the prokaryotic expression conditions were optimized. The results showed that the plasmid cultivated for 5 h， then added 0.7 mmol/L IPTG at 23 ℃ inducing for 25 h， and the xylanase activity was 52 U/mL. The optimum pH and temperature of the recombinant enzyme CBXYNA were 5.2 and 55 ℃， respectively. The metal ions of Na+， K+， Li+ and Ca2+ can enhance the enzyme activity. While Mg2+， Mn2+， Zn2+， Fe3+， Al3+ and Cu2+ can inhibit the activity of the enzyme. When CBXYNA taken water soluble corncob xylan and oat xylan， water-insoluble corncob xylan as substrate， the relative enzyme activity was 162%， 139%， 74%， respectively.

Abstract:The tolerance ability of 15 Cronobacter sakazakii isolates with different genotypes that recovered from powdered infant and baby formula （PIBF） and baby rice cereal （BRC） to different temperature， pH， and microwave， and the susceptibility to Mamiai and lactobacillus-producing lactobacillus was studied to perform some reference for infant and baby food safety. Plate counting method was employed to calculate the survival rate， which was used as the index to evaluate the tolerance ability of the bacteria， after heat， pH and microwave treatment. The rate of the diameter of the inhibition zone and the cup that put the anti-bacteria or the width of the inhibition zone to Cronobacter sakazakii was used to evaluate the susceptibility of Cronobacter sakazakii to Live Combined Bacillus Subtilis and Enterococcus Faecium Granules with Multivitamines （Product name： Mamiai） and lactobacillus. Results： The survival rate of 15 Cronobacter sakazakii isolates indicated the lethal effect of 70 ℃ was significantly higher than those of 50 ℃ and 60 ℃ （P<0.01）. The survival rates were all less than 0.11% after the isolates were treated at 70 ℃ for 20 min. A certain lethal effect was shown after treated on condition of pH 4.0， pH 6.0 and pH 8.0 for 20 min， and the survival rate of pH 4.0 treatment was significantly lower than those of the other two groups （P<0.01）. The mortality rate of majorities of the tested strains was as high as 99% after treated by microwave for 2 min， and no significant difference was found among the survival rate of the strains（P>0.05）. Lactobacillus-producing lactobacillus and Mamiai had a certain degree of inhibition to Cronobacter sakazakii， and the susceptibility of some strains was significant different （P<0.01）. Conclusion： The tolerance and susceptibility of the Cronobacter sakazakii strains were different， appropriate methods could be taken to prevent Cronobacter sakazakii contamination from infant and baby foods.

Abstract:The objectives of this study were to investigate the growth characteristics of Salmonella typhimurium biofilm（BF） on glass surface， effect of ethanol activity on the formation of S. typhimurium BF and effect of ethanol adaptation on the resistance of planktonic and BF to lethal stress. The morphology of S. typhimurium BF on the glass surface was observed by crystal violet staining， BF biomass by Thermo Scientific Microplate Reader at 570 nm and ethanol adaptation by plate colony count. Results showed that S. typhimurium BF formed on the glass surface could be directly observed by crystal violet staining， and reticular structure formed by S. typhimurium BF became denser with incubation time. Ethanol activity had significantly different effects on the formation of BF. Ethanol added at different level during 48 h incubation of S. typhimurium inhibited the formation of BF significantly， however， ethanol added after the incubation of S. typhimurium for 24 h at 5% level only promoted the growth of BF. Ethanol at level of 5% increased the tolerance of bacteria to malic acid in BF formation under the condition of 1/10 TSB. In addition， 5% ethanol adaptation increased planktonic resistance to 12% ethanol and 5 mg/mL malic acid.

Abstract:The effect of sulfur limitation on lipid accumulation of Trichosporon fermentans CICC 1368 were investigated. Firstly， lipid content in microbial cells at the end of fermentation was determined using low field nuclear magnetic resonance （LF-NMR）. Then the cell biomass， lipid concentration and fatty acids compositions were assessed. Finally， the lipid accumulation was monitored at the optimum C/S molar ratio. Results showed that LF-NMR can be used as a rapid and effective method to analyze lipid content in microbial cells. Sulfur could effectively control the accumulation of lipids. Lipid content and yield increased first and then decreased as the C/S molar ratio raised， and this indicated that limitation of sulfur should be controlled in an appropriate range. The proper limitation of sulfur would promote the accumulation of the total unsaturated fatty acids， and oleic acid content was up to a maximum of 54.9%. The biomass， lipid concentration， lipid content at a C/S molar ratio of 3310 were 21.1 g/L， 9.0 g/L， 42.3%， respectively.

Abstract:Dictyophora echino-volvata Zane， a kind of the edible Dictyophoraindusiata species， has various bioactivities. Three fractions， named as DEP-4P， DEP-6P and DEP-8P， were fractionated using gradual ethanol precipitation method from the water soluble extract of Dictyophora echino-volvata Zane. The yields of DEP-4P， DEP-6P and DEP-8P were 27.4%， 6.1% and 1.8%， successively. The contents of neutral sugar in DEP-4P， DEP-6P and DEP-8P ranged from 96.2% to 88.2%. No protein and uronic acid were detected. DEP-4P， DEP-6P and DEP-8P were identified as polysaccharides with high purity by high performance gel permeation charomatograph method. The relative molecular weights of DEP-4P， DEP-6P and DEP-8P were calculated to be 2.1×104， 6.5×103 and 1.9×103 u， successively， by referring to the molecular weights of dextran standards. Glucose was the major monosaccharide among the three fractions， while that there was trace amounts of mannose in DEP-8P. FT-IR spectra of the polysaccharides indicated that they may be α-glucans. Scanning electron micrographs showed that DEP-4P and DEP-6P performed as sheet-like appearance， while DEP-8P presented pod or line-like shape. All above， α-glucans with different molecular weights and topographic characteristics were successfully isolated from crude extract of Dictyophora echino-volvata Zane， which could lay a good foundation for further investigations in the structural features， functional proterties and applications.

Abstract:In this paper， we mainly studied the effects of cooking methods （atmospheric pressure and high pressure steaming） on the sensory and nutritional quality of steamed pork with pickled and dried mustard. The results showed that the L* values of pork decreased after steaming， and the a* and b* values increased， which indicating the pork getting darker. With the increase of steaming time， the pork gradually getting darker， the hardness， cohesion and chewiness of the pork with high pressure steaming were lower than those in the atmospheric pressure group. The central temperature of the pork in the high pressure group was higher than that in the atmospheric pressure group. The weight loss rate of pork and the weight gain rate of pickled and dried mustard were significantly increased with the increase of steaming time， and the effect of high pressure was stronger than that of atmospheric pressure. Steaming could make the TBA and POV values of the pork increased significantly， and the degree of fat oxidation increased. With the steaming time increased， the degree of fat oxidation increased， and high pressure could promote pork fat oxidation more than atmospheric pressure did. In addition， steamed pork with pickled and dried mustard made by high pressure steaming 40 min gained the highest sensory score. In this condition， the hardness， cohesion and chewiness of the pork were the lowest， and score of texture was the highest.

Abstract:In order to clarify the influence of processing parameters on the characteristics of buckwheat extrudates， to understand the relationship among different characteristics of buckwheat extrudates， and to explain the characteristics from the molecular structure level， buckwheat flour was extruded under different water content， processing temperature and screw speed by DSE-25 Twin-screw Extruder using response surface design. The physicochemical properties of buckwheat extrudates such as expansion index， water absorption index， water solubility index， and visocsity were studied systematically. The results showed that processing temperature and screw speed were important factors influencing the sectional expansion index， water solubility index and water absorption index. Moisture content and screw speed were important for the viscosity， the average molecular radius and the average molecular weight. There was a significant negative correlation between the specific mechanical energy and the starch average molecular size. Starch average molecular size was negatively correlated with water solubility index and total color difference， and positively correlated with water absorption index and viscosity. Water solubility index could be used to estimate water absorption index， and average molecular radius of the starch can be used to estimate weight average molecular weight. Starch molecules were more degraded when shear is more severe， with reduced average molecular size. With higher water content， lower barrel temperature， and smaller screw speed， special mechanical energy would be smaller， starch average molecular size would be larger， leading to higher water absorption index， viscosity， and lower water solubility index and color difference. Extrusion can be used to alter the starch structure， and the physicochemical properties such as water solubility， water absorption， viscosity can be changed accordingly.

Abstract:This research in high pressure homogeneous technology preparation of soybean protein - phosphatidyl choline nano emulsion， and the soybean protein - phosphatidyl choline nano emulsion properties and stability test analysis， soy protein was determined by the single factor response surface optimization - phosphatidyl choline compound into a stable nanometer emulsion， the optimal ratio of： soy protein 1.5%， soybean phosphatidyl choline content 0.22%， high pressure homogeneous pressure 100 MPa， the conditions of soybean protein - phosphatidyl choline average particle size of 217.43 nm nano emulsion， TSI is 3.02， emulsifying production rate was 93.35%.

Abstract:Taking dimethyl sulfoxide as solvent， soy isoflavone powder was prepared by acetone as the anti-solvent. Orthogonal experimental design method was used to in spect the major factors affecting the size and morphology of soy isoflavone powder. Results show that the particle size has a negative relationship with volume ratio， rotor speed and concentration， and has a positive relationship with reaction time. Experiment indicates that the measured powder particle size reaches 98 nm when the concentration is 300 mg/mL； rotor speed is 1 200 r/min； volume ratio is 1 ∶ 6 and reaction time is 3 min. Isoflavone and nano-isoflavone power were evaluated by using scanning electron microscope （SEM）， infrared spectroscopy （FT-IR）， differential scanning calorimetry （DSC） and statistics of powder heap density. Results showed that the chemical properties of isoflavones did not change after preparation. Nano-isoflavone particles were distributed evenly and the particle size decreased significantly.

Abstract:The nanostructured lipid carrier（RL-NLC） was developed to encapsulate， protect and deliver resveratrol and linseed oil by the hot high pressure homogenization technology. The microstructure， physicochemical stability， antioxidant activity， in vitro release， accelerated lipid oxidation and other characteristics were analyzed. The particle size of RL-NLC was about 105 nm and the PDI was about 0.216. The spherical nanoparticles could be well dispersed in aqueous and could be stored for more than 3 months at 25 ℃ without light. Encapsulated resveratrol had better antioxidant activity and slower release rate in vitro than free resveratrol. In addition， it was found that the presence of the solid lipid core and resveratrol inhibited the oxidation of linseed oil in an accelerated storage experiment at 50 ℃. The carrier loaded resveratrol and linseed oil developed in this paper may have a good application prospect in the field of functional foods.

Abstract:Seal oil is a new source of functional fatty acids， besides being rich in DHA and EPA， also contains another important fatty acid-DPA. Therefore， seal oil has good health function. Refining and esterification are important processes for high purity functional oil， which exert important influences on the product quality. Hence， it is of great significance to study the quality changes during the processes. In this paper， the effects of refining and esterification on the quality of seal oil were evaluated by physicochemical index， fatty acid composition and volatile substance， which were determined through physicochemical analysis， GC and HS-SPME-GC-MS. The results showed that refining could significantly reduce the moisture content and volatile matter （1.65% to 0.49%） and acid value （3.11 mg KOH/g reduced to 0.63 mg KOH/g）， while had no significant effect on the peroxide value. Refining and esterification reduced the content of MUFA while improved SFA and trans-fatty acid content （C18：1 trans， C18：2 trans）， had little effect on the content of EPA， DPA and DHA. 86， 50 and 44 volatile substances were detected in seal oil crude oil， refined oil and ester oil， respectively， and the total peak area of volatile substances were 83.16%， 60.06% and 36.19%， respectively. This indicated that refining significantly reduced the type and content of volatile substances while the esterification significantly reduced the content of volatile substances.

Abstract:Seven edible sea cucumbers with low economic value were hydrolyzed by three proteases including protamex， flavorzyme and papain for 4， 8 and 12 h to obtain the sea cucumber extracts， respectively. Assays for reducing power， hydroxyl radical scavenging capacity and oxygen radical absorption capacity were conducted to determine their antioxidant activities. The different sea cucumber extracts were classified in terms of extract yields， protein recovering ratios， and antioxidant activities by clustering analysis. The extract yields and protein recovering ratios of cucumaria frondosa， acaudina leucoprocta， holothuria tubulosa， holothuria scabra， and thelenata anax extracts were superior to those of stichopus variegates and holothuria keferstein extracts. And the antioxidant capacity of extract of cucumaria frondosa was the highest. The extract yields， protein recovering ratios， and antioxidant activities of the sea cucumber extracts prepared by protamex were the higest among all extracts. In terms of optimal extraction parameters， the extract yields were 41.24%-55.57%. The protein recovering ratios were 65.06%-98.4%. The antioxidant activity values including reducing power values， OH values and ORAC values were 3.41-3.41 μmol trolox equiv/g dry sea cucumber， 28.83-96.65 μmol trolox equiv/g dry sea cucumber， 38.99-133.08 μmol trolox equiv/g dry sea cucumber， respectively. The results are beneficial for processing edible sea cucumbers to obtain valuable products in food industry.

Abstract:This paper focuses on developing sturgeon skin edible gelatin products， and finds out the optimal process. Hot water extraction was used in this study， some changes of products and microstructure during processing were researched as well. The results showed the optimum conditions were extraction temperature 80 ℃， material / water ratio 1 ∶ 4 and extraction time 2 h. The physicochemical properties of sturgeon skin edible gelatin products under optimum conditions were 168.16 g gel strength； 19.3 L* of color， 8.71 a* of color， 2.25 b* of color； 32.63% recovery rate of collagen and 4.90% total solids content in liquid. Under the above conditions， it was obtained that the microstructure network with uniform pores is clear. The gelatin products are intact with good elasticity， proper hardness， bright color and desent sensory acceptance.

Abstract:Artificial neural network combined with genetic algorithm were used to model and optimize the preparation process that could orientate the preparation of chickpea protein Maillard Reaction flavor peptide. Chickpea protein hydrolysates （CPHs） with different degrees of hydrolysis （DHs） were prepared with the method of double-enzyme digestion technology. After having done the Maillard Reaction with hydrolysates， Maillard peptide produced was evaluated by descriptive sensory analysis. The proposed parameters were used to build Maillard Reaction prediction model. After the all program of the GA-BP networks， the optimized parameters were： the hydrolysis degree 24%， the initial reaction temperature 85 ℃， reaction time 31 min， initial pH 9.7 and D（+）-xylose 1.2 g. Under these optimal parameters the MRPs’ sensory score was approximately 5.0 and the sensory evaluation was excellent. The further experiment confirmed that those MRPs presented an obvious meaty and umami taste with a long duration. Thus the optimized reaction conditions could be considered as a thermal optimum reaction conditions to produce the MRPs. And the research results could provide theoretical basis and method reference for the development of high quality vegetable protein fresher seasoning.

Abstract:In order to investigate the influence of multi-strain fermentation to the flavor substances and sensory evaluation of soy sauce， there are four groups of experimental were designed： group Ⅰ （fermentation only with Aspergillus oryzae 3.042）， group Ⅱ （Aspergillus oryzae 3.042+Saccharomyces rouxii AS2.180）， group Ⅲ （Aspergillus oryzae 3.042+Saccharomyces rouxii AS2.180+Torulopsis bombicola huniang2.14）， group Ⅳ（Aspergillus oryzae3.042+Saccharomyces rouxii AS2.180+Torulopsis bombicola huniang2.14 +Lactobacillus huniang1.08）， and compared of the 4 groups after fermented 90 d. The result showed that： （1）The physicochemical indexes of ammoniacal nitrogen， reducing sugar and pH is similar， but the content of ammoniacal nitrogen in group Ⅳ is slightly higher than the other 3 groups. （2） Saccharomyces rouxii AS2.180 promotes the formation of higher alcohols and aromatic heterocyclic compounds. Torulopsis bombicola huniang2.14 promotes the formation of 4-EG and 4-VG that makes soy sauce had a special aroma. Lactobacillus huniang 1.08 makes the soy sauce tastes refreshing. And the difference of the types and content of the flavor substances is very significant of the 4 groups （P<0.01）. （3） Using suitable functions to describe the relationship between characteristic flavor substance content and the time of fermentation can get a mathematical relationship （such as： group Ⅰ y = -230.83+21.7 t - 0.136 t2 + 1.27×10-4 t3）， and can figure out the largest content of characteristic flavor substance of the 4 groups is： 648.96 μg/L （group Ⅰ： fermentation period is 92 d）， 852.90 μg/L （group Ⅱ： fermentation period is 98 d）， 982.51 μg/L（group Ⅲ： fermentation period is 99 d）， 1 897.55 μg/L （group Ⅳ： fermentation period is 102 d） respectively. Multiple fungus fermentation can increase the characteristic flavor substance content in soy sauce.

Abstract:The aims of this study were to examine the effects of using sucros utilization defective Lactobacillus plantarum starter culture in the manufacture of Chinese fermented sausage on its volatile compounds profile. Volatile compounds production was analysis using Solid Phase Micro-Extraction and Gas Chromatography/Mass Spectrometry. In addition， physicochemical parameters and microbial counts were performed thoughout the ripening in order to follow and control the process conditions. Three different batch Chinese fermented sausages were processed with Lb. plantarum WT strains， a sucrose utilization defective Lb. plantarum strains， and without starter culture， respectively. According to the data obtained in this study， the volatile flavour compounds in the treatment samples with Lb. plantarum yesN were more abundant than that of spontaneously fermented sausages. In terms of the contents of free amino acid and titratable acids， the samples with Lb. plantarum yesN were significantly superior to that of Lb. plantarum WT.

Abstract:Objective： To evaluate the removal effect of endotoxin in purification process of Cu， Zn-SOD expressed in recombinant Pichia pastoris. Methods： The active carbon adsorption and Triton X-114 phase separation were separately or jointly adopted to remove the endotoxin from Cu， Zn-SOD protein solution expressed in recombinant Pichia pastoris. Results： Both methods worked well but with different efficiency. Removal rate of endotoxin was 99.8% with the protein recovery rate of 66% after active carbon absorption combined with Trition X-114 phase separations. The endotoxin content of the final product was reduced to 26.8 EU/10 000 U determined by Limulus amebocyte lysate （LAL） assay. The residue of Triton X-114 in protein solution was 5.7 μg/mL measured by HPLC chromatography method. Conclusions： Active carbon adsorption combined with Triton X-114 phase separation is a better and economic method to purify the recombinant proteins and remove endotoxin in large scale. Both endotoxin and Triton X-114 in the purified recombinant Cu， Zn-SOD protein solution were effectively removed and their residues were well below the required limits of Chinese Pharmacopoeia.

Abstract:The effects of 1-methylcyclopropene （1-MCP） （1 μL/L）， ethylene absorbent （EA）， 1-MCP （1 μL/L） combined with EA on the shelf quality of apple after storage was carried out for 10 months after cold storage in a precise temperature control （-0.5 ± 0.3） ℃. HS-SPME-GC-MS was used to analyze the variation of volatile components among different treatments. The results showed that 1-MCP， EA， 1-MCP+EA significantly reduced the respiration rate of the fruit， delayed the emergence of respiration peak and inhibited the increase of ethylene production rate， which could effectively reduce the decrease of titratable acid and soluble solid， Maintain the fruit of the inherent hardness， recovery， cohesion， chewing and other texture， which， 1-MCP + EA the best. The main volatile substances of apple were detected by HS-SPME-GC-MS. Compared with EA alone， 1-MCP + EA treatment not only maintained the relative content of ester， but also maintained the relative content of aldehydes content of the aldehydes is mainly reduced the content of n-hexanaldehyde， and the alcohol substance mainly reduces the content of 2-methyl-1-butanol. At the same time and 1-MCP alone treatment， the effect is better to slow down the decline in aldehydes， maintaining the relative content of esters， reducing the reduction of alcohol. Through the linear discriminant analysis （LDA） can effectively distinguish the different shelf time of the apple can delay the 5 d of volatile matter change， 1-MCP + EA volatile ingredients to maintain the best.

Abstract:This paper investigated the fresh-maintaining effects of Na5（NH4）16[Mo57Mn6（NO）6O174（OH）3（H2O）24]·44H2O （abbreviated Mo57Mn6） processing on fresh-cut apples， and continuously measured five indexes， including weight loss ratio， browning degree， malonaldehyde yield， peroxidase （POD） activity and polyphenol oxidase （PPO） activity. The results indicate the processing of Mo57Mn6 can hold water and keep color effectively， and can decrease the yield of malondialdehyde and inhibit the activity of polyphenol oxidase within a week. It also can activate the activity of peroxidase in the late storage. In conclusion， Mo57Mn6 can effectively extend the shelf life of apples. The research results can provide some experimental basis for the development of novel fresh-keeping agents of fruits and vegetables， and enlarge the application scope of polyoxometalates.

Abstract:This paper studied the different concentrations of cinnamaldehyde（0， 0.1%， 0.5% and 1.0%） on the thermal inactivation of Staphylococcus aureus in ground pork ranging from 60 to 75 ℃. Different concentrations of cinnamaldehyde were added in the ground pork samples， then subjected to thermal treatment. The surviving cell number was counted on selective media. The results showed that at different temperatures， cinnamaldehyde promoted the thermal inactivation of S. aureus. Moreover， the thermal resistance of S. aureus decreased along with the increase of heat temperature and cinnamaldehyde concentration. At 75 ℃， cinnamaldehyde supplementation shortened the time needed to reach the non-detectable level of S. aureus in ground pork from 5 min to 3 min. When the inactivation curves were fitted by different kinetic models， polynomial fitting was suitable to describe the thermal inactivation regulation of S. aureus in ground pork added by cinnamaldehyde， where the secondary linear model had the highest coefficient value when different models were compared. When scanning electron microscopy（SEM） was used to observe the morphological changes of S. aureus exposed to cinnamaldehyde， the results revealed that the cinnamaldehyde ruptured the cell membrane， which leaded to the leakage of cytoplasm and might attributed to the promoting effect of cinnamaldehyde on thermal inactivation.

Abstract:Pseudomonas fluorescens was dominant spoilage bacteria in cultured fishes during the chilled storage. In the present study， the biofilm formation and spoilage phenotypes of five P. fluorescens isolates were comparatively characterized. The biofilm forming ability and adhesion of the isolates were measured by using crystal violet staining， phenol sulfuric acid assay， bead vortexing method and fluorescence microscopy. Various spoilage phenotypes inculding swimming motility， protease activity， siderophore were performed. The results showed that five P. fluorescens isolates grew fast in LB media at 28 ℃， and formed thick pellicle at the air liquid（A-L） interface for 24 h. All of them produced rapidly biofilm on microtiter plates， and PF01, PF06, PF07 and PF10 reach the maxmium amount of biomass at 12 h， however， PFuk4 arrived at 18 h. The isolates produced continuously exopolysaccharides with the extension of time and arrived to the maxmium amount at 18-24 h. Five isolates adhered to stainless steel quickly， possessed high swimming motility and protease activity， as well as production of siderophore. Only PF07 and PFuk4 were detected to short chain AHLs activity， which could be associated with higher ability of biofilm formation， adhesion， swimming and protease. The present study provided a good fundation to clarify the spoilage mechnism of P. fluorescens based on AHLs.

Abstract:The total viable counts， conductivity， whiteness， texture， water structure， total volatile basic nitrogen（TVB-N） and K value were studied in this experiment， the optimal concentration of the multiple preservative solutions during cold storage （4 ℃±1 ℃） was determined by single factor experiment and orthogonal experiment. The results showed that multiple preservative group （pepper extract 0.3%， nobilis protamine 0.3% and jerusalem artichoke extract 0.6%） had the best freshness-keeping effect compared with the control group and other treatment groups. The results showed that total viable counts， conductivity， pH and TVB-N were better than those of single preservative and blank group. Compared with the control group， the whiteness of the treatment group decreased， but the color change was not significant； texture results showed that the combination of preservative could effectively reduce the samples’ decline of hardness， resilience and other indicators. Low field nuclear magnetic resonance and water binding capacity indicated that the multiple preservative solutions could effectively prevent the conversion of combined water and immobilized water to free water. The indicators showed that the orthogonal test obtained by the best compound preservative could effectively inhibit the growth of spoilage micro-organisms， then extend the shelf life of snakeheaded fish.

Abstract:Effects of different circulation methods （cold chain and broken-off cold chain） on the quality and microbial diversity of large yellow croaker（Pseudosciaena crocea） with ice were researched in this paper. Low temperature preservation is one of the most widely used methods and cold chain logistics is a system engineering， which based on freezing technology and artificial refrigeration technology so as to guarantee the freshness of aquatic products in the periods of production， storage， transportation， sale and consumption in the prescriptive low temperature environment （0-4 ℃） all the time. But it is difficult to maintain the specified temperature in storage and transportation process for the limited conditions and high cost， so the samples were easy to be exposed at room temperature， which was represented by broken-off cold chain. Cold chain and broken-off cold chain of large yellow croaker with ice were simulated in the period of logistic process： samples in cold chain group （T1） were stored at 4 ℃ all the time， while samples in broken-off cold chain group（T2） were simulated the actual logistics process， stored at 20 ℃ when moving， transportation， distribution and sale for 2 h， 24 h， 8 h and 1 h respectively， then stored at 4 ℃ until the end of storage. The real-time temperature of samples in cold chain group and broken-off cold chain group were monitored respectively by multi-point temperature acquisition instrument. Sensory， physicochemical and microorganism indicators as Total Volatile Base Nitrogen（TVB-N）， Total Viable Counts （TVC） and Psychrophilic Bacteria Counts （PBC） were evaluated for the quality changes of large yellow croaker with ice during logistics process. The number and species changes of microorganism in samples of two different circulations were analyzed by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis（PCR-DGGE） fingerprint technology. It was found that the fluctuation of temperature between outer space and inside of box in T1 has little difference， and temperature in the center of fish body has no obvious change. However， there were great changes in temperature between outer space and inside of box in T2， when moving， transportation， distribution and sale were under the condition of 20 ℃， and the temperature of fish body in center has apparent fluctuation during the logistics process. The results showed that the deterioration of samples could be accelerated for temperature fluctuation. Circulation time was positively correlated with sensory score， microbial number and TVB-N value. Samples in cold chain and broken-off cold chain exceeded the end of shelf-life at 347 h and 275 h， TVC were （6.93±0.03）lg（CFU/g） and （6.50±0.07）lg（CFU/g）， PBC were （7.50±0.05）lg（CFU/g） and （6.82±0.04）lgCFU/g， TVB-N value were （33.47±1.12）mgN/100g and （31.04±0.06）mgN/100g respectively. The results of PCR-DGGE demonstrated that the number of Staphylococcus saprophyticus， Pseudoalteromonas sp.， Vibrio Parahemolyticus decreased， but the number of Pseudomonas sp. and Psychrobacter sp. increased gradually in later circulation， Acinetobacter sp. and Shewanella sp. were also occupied a certain proportion. In conclusion， the shelf-life of large yellow croaker in cold chain and broken-off cold chain were 275-347 h and 203-275 h respectively. Pseudomonas sp. and Psychrobacter sp. were the special spoilage organism of large yellow croaker in the later of cold-chain and broken-off cold chain process.

Abstract:To explore the structural characteristic and enzymatic mechanism for melanosis development of Litopenaeus vannamei during cold storage， the cell integrity in hepatopancreas tissue was monitored by histochemistry and transmission electron microscope. The results showed that the cell structure of hepatopancreas tissue raptured gradually as the increase of storage， thoroughly disintegrated on the 5th day. In addition， the image with low-field nuclear magnetic resonance indicated the fast increase in content of free water in tissue as the disruption of cell structure. Furthermore， the results of immunohistochemistry with Ca2+ fluorescence probe and serine protease demonstrated that Ca2+ and serine protease regularly migrated with disruption in cell structure and water migration. With combination of these driving forces， the pro-polyphenol oxidase was activated and the melanosis development was triggered and accelerated.

Abstract:Membrane-bound polyphenol oxidase （mPPO） in Fuji apple （Malus domestica Borkh. cv. Red Fuji） （mPPO） accounted for about 90% of apple polyphenol oxidase， while there was little knowledge about mPPO properties and functions. In this paper， we analyzed bioinformatics of mPPO （including amino acid composition and properties， secondary structure， trans-membrane structure， subcellular localization， etc.） based on the prophase of mPPO primary sequence， using prediction technology， in order to provide new ideas to study mPPO structure and provide a theoretical basis for exploring the role of mPPO in apple postharvest physiology. The results showed that： the highest level of amino acid content in mPPO was Thr（8.7%）， followed by the Asp （7.8%） and Leu （7.8%）. There were no Pyl and Sec. Histidine （His） Play an important role on mPPO function while its content is just 2.5%. From the result of amino acid composition， the proportion of hydrophobic amino acids in mPPO was above 40% and the exposed surfaces （exposed） residues was 45.74%. Theory of mPPO stability index was 41.72， which indicates that the mPPO was an unstable protein. The secondary structure of mPPO showed that the alpha helix was 18.67%， and beta folding structure content was 23.33%， the rest of the random coil was 58.00%. mPPO protein did not contain 310 spiral， spiral， Pi beta bridge， beta Angle， bending structure， and other structures. The calculation of sub-cellular localization indicated that mPPO from Fuji was a hydrophobic membrane protein in chloroplast with a 39 amino acid residues signal peptide and two extracellular membrane peptides （82-97 for N-， 548-567 for C-）.

Abstract:Electronic Nose was used to analyze the volatile components of fresh yak meat after processed under different storage conditions； and then， the correlation analysis between volatile components and total volatile basic nitrogen （TVBN） was done and obtained a report about usage of electronic nose for evaluation of the freshness of the yak meat. The results displayed that storage time and temperature had a greater impact on the volatile composition of yak meat， the response values increased with the extension of storage time； in the same storage time， the higher the temperature the higher the value of the response of the sensor. Principal component analysis showed that the pre- storage of and post-storage samples distributed in different areas， and the sum of PC1 and PC2 reached to 94.849% which meant the samples could distinguish effectively. It had good consistency with sensory evaluation results. Further analysis on the results of the electronic nose and total volatile basic nitrogen （TVBN） was carried out； it showed that each sensor had a higher correlation between the response values and TVBN with correlation coefficients higher than 80.00%. Basis on the results of multiple linear regression analysis， the model between 10 response value and TVBN was established and the model coefficient of determination and residual standard deviation reached to 0.9983 and 0.18561， respectively， which indicated that it had high reliability and could predict the freshness effectively. Compared to previous studies， a more comprehensive， systematic measurement of yak meat nutrition was performed in this experiment.

Abstract:Purpose： An indirect competitive enzyme-linked immunosorbent assay （ic-ELISA） for detection of aflatoxin B1（AFB1） in peanut was developed. Methods： The AFB1 antigen was prepared， and coated in 96 well plates with the content of 0.1 μg/well； antibody was diluted 64 000 times； the 0.1% skimmed milk powder solution was selected as the blocking buffer， 0.01 mol/L phosphate buffer solution （PBS， pH 7.4） was used as dilution buffer to establish the proposed ic- ELISA detection method. Results： The limit of detection limit （LOD， IC15） of this ic-ELISA assay was 0.0066 μg/L； the sensitivity （IC50） was 0.027 μg/L； and the linear range was 0.0097-0.088 μg/L （R2 = 0.999）. The intra-assay variation coefficient （n=6） range was 0.29%-16.9%， and the inter-assay variation coefficient （n=6） range was 0.22%-21.19%. The sensitivity（IC50） in peanut sample was 1.04 μg/kg， and the recovery range was 96.67%-106.51%. Conclusion： The ic-ELISA assay established in this study was simple， sensitive and accurate and can be used for quantitative determination of AFB1 in peanut samples.

Abstract:Seven molecular species of microcystins were qualitatively and quantitatively analyzed by both high performance liquid chromatography-tandem mass spectrometry （LC-MS/MS） and direct injection analysis （DIA）. The advantages and disadvantages of these two methods in precision， sensitivity and economy were compared， which were further used for the detection of microcystins in Melanioides. For LC-MS/MS method， the Waters XSelect HSS T3 （2.1 mm × 150 mm， 3.5 μm） was used as separation column with mobile phase of acetonitrile（0.1% formic acid） and water （0.1% formic acid）. The MS was operated in electrospray ionization（ESI） and multiple reaction monitoring mode（MRM） with linear range of 0.9965~0.9993 and relative standard deviation of 3.6%~6.1%. The limit of detection and the limit of quantitation were less than 0.54 ng/mL and 1.81 ng/mL， respectively. The recovery ranged from 73.9% to 83.4%. For DIA method， the fragment m/z 135.2 was selected as the characteristic ion with DP 60 eV and CE 55 eV. After precursor ion scanning （PreIS）， the microcystin were mainly ionized as [M+2H]2+. The comparison results of these two methods showed that the performance of LC-MS/MS was better than that of DIA， while DIA was faster in detection speed， which only cost one min to complete the determination of seven molecular species of microcystins. Finally， a total of 60 samples was analyzed by the two methods. The results showed that the positive samples were 63.3%， and the main pollution species were Mc-RR and LR. The results suggested that when the number of samples to be tested was large， DIA should be used for initial screening. For the positive samples， LC-MS/MS should be used for the secondary testing， which could effectively reduce the detection time， column loss and solvent consumption， and improve the reliability of the results. This analysis strategy can be applied to fast analysis of microcystins in water， animal， and plant samples， determine the monitoring and sampling position and frequency， the alert value， and the prevention and control， etc. This study could provide scientific basis for related departments to improve and strengthen the monitoring and management of aquatic products. It also could ensure the food safety and the development of offshore aquaculture.

Abstract:Volatile aroma components in 4 kinds of mackerel samples （fresh， cooked， air-dried， sun-dried） were extracted by solid phase microextraction （SPME） and analyzed by gas chromatography and mass spectrometry（GC-MS） to qualitative and semi-quantitative analysis. The contributions of volatile compounds were evaluated by a relative odor activity value（ROAV）. The results showed that totally 37，47，42 and 43 kinds of volatile compounds in fresh， cooked， air-dried and sun-dried mackerel were detected； hydrocarbons were found to be the most abundant volatile compounds in fresh mackerel， and aldehydes were found to be the most abundant volatile compounds as a consequence of aggravated lipid oxidation during the drying process； nonanal， hexanal， benzaldehyde， phenylacetaldehyde， 2-nonanone， 2-undecanone and ethylbenzene were the key volatile compounds in the fresh mackerel； nonanal， undecanal， hexanal， benzaldehyde， 2-nonanone， 2-undecanone were the key volatile compounds during the drying process.

Abstract:The highly thermosensitive mutant Z114 can be easily released intracellular protein to extracellular environment， when the cells form the Z114 are incubated both in the low-osmolarity water and at the non-permissive temperature （usually 37 ℃）， the fermentation condition is the pH natural， the fermentation temperature 28 ℃， the yacon extract 180.0 g/L， soybean cake hydrolysate 25.0 g/L， ammonium sulfate 15.0 g/L， the crude protein content was 59.1% attained at 45 h of the fermentation. The attained cell from the mutant Z114 were treated at 37 ℃ overnight， there was 61% intracellular protein that was released from the mutant cell. The content of the protein produced by the mutant Z114 was kept high level， the essential amino acids and other nutrients were rich. This means that the yacon extract could be used as the medium for growth of the highly thermosensitive to produce to protein.

Abstract:Carotenoids are important micronutrients and their specific health benefits have been associated with the consumption of food products rich in carotenoids such as fruits and vegetables， as well as their bioavailability. However， given their specific cellular location， form of existence and high hydrophobic character， the uptake of carotenoids from food products is generally quite low. The present review summarizes recent studies on fruits and vegetables in which specific product characteristics， i.e. form of existence，（micro） structure characteristics and the presence or addition of lipids， are linked to carotenoid bioavailability. The review could provide the basis for a critical and detailed identification of parameters or conditions that are crucial in the development of fruit- and vegetable-based food products containing higher amounts of carotenoids in an absorbable form， as well as corresponding processing procedure. Additionally， future research challenges of carotenoid bioavailability in this context are identified.

Abstract:Pectin is one of the most important components in cell wall materials of higher plants with the ability to maintain the integrity of cell wall architecture， which is closely related to the texture change of fruits. This review describes the structure and models of pectin， and the changes of pectin’s contents， components， neutral sugars and polymers’ nanostructure in some common fruits. Furthermore， this review analyses the degradation patterns of pectin in different fruits during softening， hoping to make reference for further understanding the role of pectin metabolism in different softening patterns of fruits.

Abstract:It is well known that the milk fat globular membrane （MFGM） is a complex three-layer structure encapsulated in the outer layer of fat globules. MFGM consists of a variety of biologically active molecules， in which phospholipids and protein accounted for more than 90% of the dry weight of MFGM. The phospholipids as MFGM skeleton play an important role in the MFGM emulsification， stability and other functional characteristics. In this paper， the changes of MFGM phospholipids and the kinetic studies of phospholipid domains in the process of milk processing were reviewed. Meanwhile， this paper provided scientific reference for the optimization of dairy products processing technology.