Abstract:Cold storage is an effective way to control the quality and extend the shelf life of post-harvest fruits and vegetables. However，the inappropriate cold storage would cause chilling injury. The research process of chilling injury on post-harvest fruits and vegetables in cold storage is reviewed here，summarizing the internal and external factors affecting chilling injury，the mechanisms and symptoms，the relevant changes of physiological and biochemical index （especially the effects on the cell membrane permeability，antioxidant enzyme activity，the ultra-structures of cell tissues for the post-harvest fruits and vegetables），and the methods to prevent and alleviate chilling injury.

Abstract:In previous work，we screened a strain（Bacillus licheniformis JXC-1） producing solvent-stable（10% N，N-Dimethylformamide，short for DMF） α-glucosidase from several different soil samples. In this work，we attempted to determine the key factors for the production of α-glucosidase and optimize the feeding strategy in a 3-L fermenter. Results showed that the enzyme activity reached 444.7 U/L with the optimal condition（pH 7.0，the initial maltose concentration 25 g/L，and agitation speed 600 rpm）. The strategy of feeding maltose and tryptone at a rate of 2.25 mL/h（4-5 h），6.75 mL/h（5-6 h），9 mL/h（6-7 h） and 15 mL/h（7-8 h） significantly increased the production of α-glycosidase from 444.7 U/L to 872.5 U/L.

Abstract:To further isolate and identify the lipophilic alkaloids （active ingredient） from the Chinese herb，embryo loti （the green embryo of mature seed of Nelumbo nucifera Gaertn.）. According to the chemical properties of lipophilic compounds and phenolated alkaloids，the lipophilic components of embryo loti were separated into two groups：the phenolic and the non-phenolic components. Then various column chromatographic techniques were used to isolate and purify the two components. The chemical structures of the compounds were determined from the analysis of their physicochemical properties and spectrum study，i. e.，UV，IR，MS，1H NMR，13C NMR and 2D-NMR，ect.. Tweleve different monomers were obtained from the lipophilic extraction of embryo loti，and 10 of them were identified as alkaloids. Six phenolic compounds were identified，including l- menthol，neferine，amepavine，4'-methoxy-N-methyl coclaurine，isoliensinine and liensinine. Six non-phenolic compounds were also determined，such as -sitosterol，nuciferine，pronuciferine，lysicamine，N-methoxycepharadione B and N-methylcordaldine. Among them，l- menthol，4'-methoxy-N-methyl coclaurine，lysicamine，N-methoxycepharadione B and N-methylcordaldine were first reported here.

Abstract:Antroquinonol，one of the metabolites in the edible and medicinal mushroom Antrodia camphorate，is considered as an effective bioactive component. However，Antroquinonol could not be biosynthesized via conventional submerged fermentation of A. camphorata. In this study，the culture medium and submerged fermentation conditions for the biosynthesis of Antroquinonol from A. camphorata was optimized based on the addition of precursors and effectors. The carbon/nitrogen source and the culture conditions of A. camphorata in submerged fermentation were optimized by single factor experiment with soybean oil and coenzyme Q0 added. The optimal carbon source was rice flour of 50 g/L，while the nitrogen source was soybean flour of 6 g/L and corn steep powder of 8 g/L. The initial pH is pH 6 with the inoculums concentration of 10% （v/v），and the fermentation temperature is 25 ℃ at 150 rpm，under which the production of Antroquinonol can reach 170.34 mg/L.

Abstract:The alkali and alcohol soluble extracts from the defatted rice bran exhibit a good antioxidant activity in vitro. The antioxidant effects of the extracted antioxidants from the defatted rice bran on scavenging free radicals and lipid peroxides aganist oxidative damage system were studied by hydroxyl radical system，DPPH radical system，superoxide anion radical system，linoleic acid system，pure lard system，ORAC system，and PC12 cells，respectively. The scavenging rate of ·OH was over 50% for the extracts of 0.2 g/mL，while the clearance rate of DPPH was as high as 90% for 0.6 mg/mL extracts. The O2- clearance rate is about 50% for the extracts of 45.0 mg/mL and the ORAC value reached a comparable value with sodium D-isoascorbate when the extracts concentration was larger than 60 μg/mL，In linoleic acid system，a significant antioxidant activity was observed for the extracts of 500 μg/mL. At the meanwhile，the effect was better than sodium D-isoascorbate with same concentration for the extracts of 500 μg/mL and 1 mg/mL. In lard antioxidant studies，a longer duration was required for pov growing to the same level if the lard samples added with 5% extracts. The PC12 cell viability presented a successively increasing trend when the sample concentration increased，for example，the PC12 cell viability reached to 82.2% with 5 mg/mL sample added and the antioxidant effect was better than Trolox of 200 μmol/L.

Abstract:A high-efficient and broad-spectrum bacteriocin was developed as a natural food preservative. The lactic acid bacteria were isolated from the home-made yogurt，the marketed unpackaged pickles and the bagged pickles，respectively，using the scrip double-layer plate assay. The isolated lactic acid bacteria was processed by bacteriostasis test，the inhibitory effect test of acid and hydrogen peroxide scavenging，the susceptibility detection of proteinase，and the antibacterial spectrum determination. Finally，the morphologies as well as the physiological and biochemical characteristics of strains were identified. Five lactic acid bacteria strains with higher antimicrobial activity were successfully isolated. Their fermentation supernatants obtained great antimicrobial activity after the exclusion of interference from acid and hydrogen peroxide，while a decrease of the antimicrobial activity was observed after proteinase treatment. The results indicated the isolated strains were proteinaceous bacteriocin. Five strains exhibited high antimicrobial activity against Pseudomonas aeruginosa，Staphylococcus aureus，Bacillus subtilis and Escherichiacoli. The strain E2-2 was selected as the strain of the best antimicrobial activity，which was preliminarily identified as Lactobacillus pentosus.

Abstract:The Tetragenococcus halophilus species is a halophilic lactic acid bacteria （LAB） exhibiting in the later fermentation of soy sauce moromi. The arginine metabolism of this species is closely related to the accumulation of citrulline which is the main ethyl carbamate precursor in soy sauce. A Tetragenococcus halophilus strain R23 was isolated from moromi by selective medium cultivation and PCR （targeting on the groEL gene） screening. The arginine metabolism of the strain was investigated under different cultivation temperature and salt concentration. A highest utilization of arginine and citrulline for T. halophilus R23 was observed at 30 ℃ in the presence of 180 g/L NaCl，with degradation rate of 100.0% and 64.3%，respectively. In addition，there was no citrulline detected with in arginine consumption of R23，which provided a potential application of citrulline reduction in soy sauce during fermentation process.

Abstract:The bioactive component of chestnut shell and its inhibitory effect on the food-borne microbes were studied，and preliminary test of its preservation function was carried out in a food system. The chestnut shell crude extracts were separated by MCI column and the inhibitory effects were investigated via agar diffusion method and macrodilution broth method on four bacteria and two fungi. Column separation showed that the activity component of chestnut shell is hydrolysable tannin，in vitro antimicrobial assay showed that chestnut shell tannin possesses a remarkable antimicrobial activity against tested food-borne microbes including Escherichia coli，Staphyloccocus aureus，Bacillus subtilis，Salmonella typhimurium，Aspergillus niger，Penicillium citrinum with the minimum bactericidal concentration（MBC） values in the ranges of 0.062 5~2.5 mg/mL on bacteria and 20~40 mg/mL on fungal spores，but with no inhibitory effect on fungal hyphae. Food preservation experiment indicated that the chestnut shell tannins have a basically identical antiseptic capacity than sodium benzoate in apple juice.

Abstract:The study aimed to display trehalose synthase（TS.EC 5.4.99.16）on the surface of Pichiia pastoris and investigate its enzymatic properties. Synthesized gene from Streptomyces coelicolor trehalose synthase and yeast cell wall protein GCW14 was cloned to pPIC9k carrier and transformed into yeast GS115 and thus the pPIC9k-GCW14-TS carrier was constructed to display TS. Then the properties of the recombinant trehalose synthase were determined. Results showed that the recombinant trehalose synthase possessed the optimal temperature 30~45 ℃ and pH 8.5，K+ and Mg2+ increased its enzymatic capacity and more than 75% of the activity was still remained after it was reused for 5 times. Therefore，this recombinant strain can be repeatedly use as a whole cell catalyst to convert maltose into trehalose.

Abstract:Temperature changes during radio frequency thawing （RFT） of frozen pork were investigated using theoretical simulation and experimental determination. The feasibility of simulating temperature changes during RFT of frozen pork using the software COMSOL Multiphysics has been confirmed，which suggests the optimization of RFT conditions could be easily determined by software instead of time-consuming and laborious experiments. Dielectric properties of pork at 27 MHz were estimated within -18 to 20 ℃. A coupled electro-quasistatic-thermal model was established using finite element method to simulate the RFT process. The effects of temperature changes during RFT of frozen pork were studied，such as the electrodes distance and meat thickness. The simulation results showed a good consistency with the experimental determinations. Thawing rate changed from fast （-18 ℃~-5 ℃） to slow （-5 ℃~-1 ℃），and turned back to fast （>-1 ℃）. A longer thawing duration was required if the electrodes distance and meat thickness were increased，while a better temperature distribution could be received if the electrodes distance was increased but the meat thickness was decreased. The relationship of radio frequency conditions，material properties and thawing effects has been established via the simulation of temperature changes during RFT of frozen pork. The confirmation of predicting thawing process by software simulation provides a wide range of application perspective for RFT.

Abstract:The degradation kinetics of anthocyanins under 200，400 and 600 MPa treatment was studied using blueberry juice and a simulated juice to understand the anthocyanins stability during high hydrostatic pressure processing and the mechanism of anthocyanins degradation was discussed. A decrease of anthocyanins content in blueberry juice was observed with 200MPa and 600 MPa treatment，and the anthocyanins content in the simulated juice also decreased under 600MPa processing. The degradation of anthocyanins in blueberry juice and the simulated juice followed the first-order kinetics. The degradation of anthocyanins under high hydrostatic pressure treatment was not only caused by the enzyme and heat，but also caused by the pressure. The mechanism of anthocyanins degradation calls for further investigation.

Abstract:The oil contained in the microalgae was considered as an ideal raw material for biodiesel. In order to screen microalgae that have the potential to produce oil，eight strains of microalgae were isolated from natural water and evaluated for their growth，biomass and fat content. A highly efficient oil-producing microalga CC-B3 was found with the total lipid content 36.30%，biomass 2.43 g/L and oil yield 62.9 mg/（L·d）. Base on the 18s rRNA，the strain of algae was identified to be Scenedesmus obliquus and its phylogenetic tree was thus constructed.

Abstract:The effect of polysaccharides from Wolfiporia cocos （Schw.） Ryv. & Cilbn（WRP）to the antioxidant capacity and protein Bax，Bcl-2 gene expression of renal tissues in mice with type II diabetes were studied. Non insulin dependent （type II） diabetes mellitus （NIDDM） was induced by the combination of high-carbohydrate/high-fat diet-fed and low dose of streptozotocin （STZ）. Mice were randomly assigned to four treatment groups：the control group，the NIDDM group，the group fed WRP diet and the group fed rosiglitazone diet. The antioxidant capacity and the expression of Bax and Bcl-2 in renal tissues of mice were investigated. The superoxide dismutase （SOD） and glutathione peroxidase （GPx） levels in NIDDM mice were increased while the malondialdehyde （MDA） level was decreased after fed with WRP，which indicated that WRP could protect kidney from the damage caused by diabetes by improving the antioxidation activity of kidney，reducing lipid peroxidation and preventing free radical induced oxidative stress. WRP could restrain excessive expression of bax gene in NIDDM mice and inhibit apoptosis of renal cells，which indicated preventive of diabetic nephropathy.

Abstract:The lipases immobilized on active carbon，silica gel G or DM-130 macro porous resin by adsorption were steeped in various organic solvents to improve the activity and stability for catalyzing transesterification. It was found that the activities of immobilized lipases could be increased with acetone，1-propanol，2-propanol and ethyl acetate，but could be deactivated with methanol，n-hexane and cyclohexane. Compared with the immobilized lipases dried directly after adsorption，the immobilized lipases treated in 2-propanol or ethyl acetate for 1 h displayed 1.70 to 2.25 times enzyme activities，their half-lives were prolonged 3.2 to 8.4 h and the operation lives were increased 2 to 5 batches for soybean oil transesterification. The thermal stability of the immobilized lipases could also be enhanced by the treatment with 2-propanol or ethyl acetate.

Abstract:Compared with some commercial proteases，acid protease（Ap） from Aspergillus oryzae has high hydrolysis efficiency and produces soy hydrosates with weaker bitterness. In order to uncover the structural characteristics，Ap gene from A. oryzae was cloned by RT-PCR technology，and then was analyzed with bioinformatics technology. Results showed that Ap gene had a preference for codon usage，especially for the third codon with the 74% usage frequency of GC base，and encoded 404 amino acid residues. Ap was an extracellular aspartic proteinase. According to the structure obtained by homology modeling with acid protease from A. phoenicis（PDB code：1IBQ），Ap was found to possess at least two Zn2+ binding sites，one disulfide bond，163 hydrogen bonds，35 salt bonds，and two solvent accessible surfaces of D33（4.7849?魡2） and D215（3.5941?魡2）. Though the spatial structures of Ap and 1IBQ were similar，residues of some important sites（such as flap ring，angle and ψ-loops） were conservative.

Abstract:Single factor and orthogonal experiments were applied to investigate effects of different nutrients and conditions on the fermentation of arachidonic acid by M. alpina. Results indicated that corn and soybean meal were preferred for fungal growth and lipid accumulation. With a temperature-shift strategy the fermentation time was shortened two days. Arachidonic acid reached the maximum yield（13.6 g/L） when the medium was comprised of 66 g/L corn meal，54 g/L soybean meal，3 g/L KH2PO4，1 g/L MgSO4 and 2 g/L Na2SO4.

Abstract:Sulfation of polysaccharides can improve their biological activities. To efficiently prepare the sulfated extracellular polysaccharide from submerged fermentation of Ganoderma Lucidum，microwave assisted synthesis was established in this paper，using dimethylformamide as solvent and aminosulfonic acid as esterifying reagent. Results showed that the microwave assisted synthesis with urea as catalyst led to a high substitution degree of 2.67，and the reaction was mild. Thus，microwave assisted synthesis is a new approach to obtain sulfated polysaccharides with high degree of substitution.