Abstract:Amino acid analysis is used to determine the amino acid content of amino acid-,peptide-and protein-containing samples.In the last decades,amino acid separations have been carried out mainly by ion-exchange chromatography with post-column derivatization and RP-HPLC with pre-column derivatization.Along with the modern technique of amino acid analysis,high throughput and sensitivity mass spectrometry has been widely used in the analysis of amino acids and brings significant benefits.This review focus on the application of the gas chromatography,liquid chromatography and capillary electrophoresis in combination with mass spectrometry in the analysis of amino acids,for which comparison are made.

Abstract:To conquer the survival decline of direct vat set(DVS) starter during freeze-drying process,Lactobacillus casei Zhang was used to investigate the effect of different cryoprotectants on physiological activity of cells.The results showed that with the participation of traditional freeze-drying protective agents such as skimmed milk and sorbitol,the survival rate of freeze-dried cells improved to 54.5% by adding 5 g/L glutathione(GSH),and the number of viable cells increased to 6.16 ×10 8 cfu/mL.Further analysis indicated that GSH improved the instauration of cell membrane fatty acids(U/S value) after freeze-drying treatment by 2.02 times compared with the control sample,while it reduced the chain length of saturated fatty acids from 17.1 to 16.0.In addition,the result of transmission electron microscope(TEM) suggested that GSH is able to maintain the integrity of cell membrane structure effectively in freeze-drying process.All of these results provide a constructive way to find novel cryoprotactants based on the understanding of the physiological changes of microbial cells during the freeze-drying process.

Abstract:β-mannanase and xylanase are extensively used in food industry.Synergistic action between the two enzymes is obersved to effectively improve digestibility of the hemicelluloses of food material.In order to coexpress β-mannanase gene and xylanase gene in Pichia pastoris,pPIC9K-xynⅡ was linearized with Sal I and transformed into GS115/Anman5A by electroporation.GS115/Anman5A-xynⅡ with high production of β-mannanase and xylanase was screened by using G418.SDS-PAGE demonstrated two protein bands with apparent molecular weight of about 52 000 and 24 100.One GS115/Anman5A-xyn Ⅱ transformant producing the highest activities of two enzymes in shake flasks was selected and numbered as GSMX2.Subsequently the expression conditions for enzymes production by using GSMX2 were optimized,the optimum expression conditions listede as follows:initial pH 7.0,glycerol concentration 1.5%,methanol concentration 1.5%,induction for 120 h.Under these conditions,the activities of β-mannanase and xylanase were achieved at 37.1 U/mL and 193.6 U/mL,respectively.

Abstract:Thickness is an important index for the grade of green soybean.In this manuscript,hyperspectral imaging technology was used to determine the thickness of two hundreds green soybean.The hyperspectral reflectance images of the samples were acquired using hyperspectral imaging system and the instrumental thickness values were measured by digital caliper.The range of 400 ～1000 nm spectral information was preprocessed using multiplicative scatter correction algorithm(MSC),standard normal variate algorithm(SNV) and derivation calculation algorithm,respectively.Then,partial least squares(PLS) and multiple linear regressions(MLR) were used to develop calibration and prediction model.Results show that optimal models are obtained by MSC coupled with PLS method,which the correlation coefficients of calibration set and prediction set were 0.956 and 0.933 and the root mean square error is 0.59 mm and 0.70 mm,respectively.The aboved results demonstrated that hyperspectral imaging technology is suitable for detection of green soybean thickness e.

Abstract:Effect of sodium silicate treatment on pink rot of apricot fruit(cv.Lixing) and its partial mechanism were studied in this manuscript.Inhibitory effect of sodium silicate on Trichothecium roseum was evaluated by in vitro.Apricot fruits were dipped with sodium silicate at different concentration(0,25,50 and 75 mmol/L) for 10 min,the inhibition effect of treatment on the lesion diameter of fruit inoculated with T.roseum were investigated during storage at room temperature.Two defense enzyme peroxidase(POD) and polyphenol oxidase(PPO) activities and disease resistance substances total phenolic and flavanoids accumulation in fruits were also detected.The results showed that sodium silicate significantly inhibited mycelial growth of T.roseum in vitro,with the inhibition rate of 85% when 25 mmol/L sodium slicacate was used.Moreover,application of sodium silicate reduced pink rot development on artificially inoculated apricot fruit.It was found that 50 mmol/L sodium slicacate showed the highest inhibitory effect on pink rot for 72 h.Furthermore,Sodium silicate treatment increased the activities of peroxidase(POD) and polyphenol oxidase(PPO) in apricot fruit,enhanced accumulation of total phenolic.However,no significant difference was found in flavanoids between treated and control fruit.Therefore,it is suggested that postharvest sodium silicate treatment can reduce pink rot in apricot fruits by inhibiting the growth of pathogen and inducing resistance in fruit.

Abstract:In this manuscript,the blanching treatment technology with color fixation was investigated to develop an efficient process for keeping color stability of green soy bean during processing and storage.According to the response surface methodology,the optimum conditions was determined and listed as follows blanching temperature 100 ℃,blanching time 3 min,,the zinc acetate concentration 0.06% and the ascorbic acid concentration 0.14%.under the optimum conditions,the peroxidase activity was inhibited and the stability of food color was ensured.

Abstract:In this manuscript,a magnate solid phase extraction-high performance liquid chromatography-tandem mass spectrometry(MSPE-HPLC-MS/MS) method was established to determine the migration of 4,4’-Bis(dimethylamine) benzophenone,4-(Dimethy lamino) benzophenone,2-Isopropythioxanthone from paper package.The analytes was separated on an Agilent Eclipse AAA C18 column with a mobile phase of methanol-water in gradient elution mode at the flow rate of 0.5 mL/min,the mass spectrometry worked in positive ion mode.Moreover,the extraction parameters which affect efficiency were optimized and the results demonstrated that a good linearity in the concentration range of 0.5 ～50.0 ng/mL for 3 analytes.The correlation coefficients were all higher than 0.999.Average recoveries of 3 analytes at three spiked level ranged from 78.3 to 92.1 %,with RSDs less than 7.4 %.The limits of quantification and detection of the method was 0.5 and 0.2 ng/mL,respectively.The method was proven to be sensitive and simple,and was suitable for the rapid determination the real migration of 4,4’-Bis(dimethylamine) benzophenone,4-(Dimethy lamino) benzophenone,2-Isopropythioxanthone from paper package.

Abstract:In order to establish the relationships of the visible and near infrared diffuse reflection(VIS/NIR) spectroscopy and peel browning and flesh browning of Mopan persimmon,calibration results for peel color b* and flesh turbidity of Mopan persimmon were compared with different treatment methods in the whole spectral region between 570 and 1 848 nm.The results showed that the modified partial least squares(MPLS) model,with respect to original spectra and None treatment,provided better prediction performance for peel color In order to establish the relationships of the visible and near infrared diffuse reflection(VIS/NIR) spectroscopy and peel browning and flesh browning of Mopan persimmon,calibration results for peel color b* and flesh turbidity of Mopan persimmon were compared with different treatment methods in the whole spectral region between 570 and 1 848 nm.The results showed that the modified partial least squares(MPLS) model,with respect to original spectra and None treatment,provided better prediction performance for peel color b * of persimmon,with correlation coefficient of prediction(R p 2) and the root mean square error of prediction(RMSEP),ratio performance deviation(RPD) of 0.968,1.417 7,and 7.92 respectively.And the partial least squares(PLS) model,with respect to the first derivative D1 log(1/R) and None treatment,provided better prediction performance for flesh turbidity of persimmon,with R p 2,RMSEP and RPD of 0.757,0.107 9,and 2.22 respectively.Therefore,nondestructive measurement of peel color b * and flesh turbidity of Mopan persimmon using VIS/NIR spectroscopy technique was feasible.of persimmon,with correlation coefficient of prediction(R p 2) and the root mean square error of prediction(RMSEP),ratio performance deviation(RPD) of 0.968,1.4177,and 7.92 respectively.And the partial least squares(PLS) model,with respect to the first derivative D1 log(1/R) and None treatment,provided better prediction performance for flesh turbidity of persimmon,with R p 2,RMSEP and RPD of 0.757,0.107 9,and 2.22 respectively.The aboved results demonstrated that VIS/NIR spectroscopy technique was feasible to nondestructive determination of peel color b * and flesh turbidity of Mopan persimmon.

Abstract:The pasting properties and particle size distribution of long-shapedrice and round shapedrice starches isolated from alkaline process,neutral protease process and alkali protease(pH= 8,pH=10) were compared.The results indicated that the protein residual rate of rice starch from alkaline isolation was lower than that from enzymatic isolation,but former damaged the starch granules partially.And the pasting curve of the long-shapedrice starch from neutral protease and alkali protease(pH =10) isolation was similar to that of native long-shapedrice flour,while the pasting curve of the round-shapedrice starch from neutral protease and alkali protease(pH =10) isolation was similar to that of native round-shapedrice flour.The neutral protease isolation also produced the smallest franule size of round-shapedrice starch.In conclusion,the quality of round-shapedrice starch isolated from neutral protease process was the greatest.

Abstract:Six strains with manganses peroxidase-producing capability were screened from the soil samples which were collected in a Wood factory,Wuxi,China.The strain J09 which has the highest yield was identified as Sinorhizobium meliloti.The enzyme activity reached the peak of 607.7 U/L at the third day under the optimized conditions.For the crude enzyme liquid and fermentation medium with initial concentration of 15 mg/L malachite green,the decolorization rate could reach more than 75% and 85% by 3 hours respectively.Under aerobic condition the decolorization rate was higher than that under the anaerobic condition and malachite green has some toxicity to the bacteria.

Abstract:In this manuscript,the effect of chitin nanowhisker(CNW)/polylactic acid(PLA) nanofiber film on the preservation of strawberries was investigated.The decay index,weight loss,titratable acidity content and VC content of strawberries packaged with CNW/PLA nanofiber films were determined and compared,and the results indicated that CNW/PLA nanofiber film could decrease the decay index and weight loss,and delay the decline of titratable acidity and vitamin C contents.Furthermore,CNW/PLA nanofiber film exhibited strong antisepsis preservation on the strawberries.

Abstract:Using Salmonella enterica DSM 17058 T as the research model,the protein fingerprint of Salmonella was studied to obtain an accurate identification result based on MALDI-TOF-MS.In order to achieve a good reproducibility of the protein map and establish the standard analysis method by MALDI-TOF-MS,different mediums,culture times and sample handing methods were optimized.The results showed that more characteristic peak of protein with smooth baseline,less noise and higher signal-to-noise ratio were obtained by ethanol/formic acid treatment method.Taking Columbia Agar Base as the culture medium,the protein map with strong signal and good repeatability was acquired after 24h,which took less time compared with other mediums.

Abstract:In order to investigate the influence of reaction time on the antioxidant activities of the chitosan oligosaccharide(COS) derivatives,two kinds of COS derivatives were prepared through Maillard reaction by heating COS and xylose with 4 h and 8 h separately(the ratio of-NH2 and C=O was 1∶1),named CX4 and CX8.The absorbance and fluorescence were determined during the reaction.The chitosan oligosaccharide derivatives were characterized by FTIR and their molecular weight was determined by GPC.Their antioxidant activity was investigated by employing various established in vitro systems,such as superoxide/hydroxyl/1,1-diphenyl-2-picrylhydrazyl(DPPH) radicals scavenging and reducing power.The results as flowers:the UV-Vis absorbance at 278 nm had a sharply increase within the first 2 h,which attribute to the Maillard intermediate products;The fluorescence intensity(Ex 343 and Em 435 nm) sharply increased within the first 2 h with a subsequent decrease when heating time increased.Though the Maiilard intermediate products and fluorescence prouducts had not accumulated after 4 h,the derivatives of 8 h showed stronger antioxidant activity compared to the derivatives of 4 h.The antioxidant activity was found to be in the order of CX8>CX4>COS,which indicated that the derivatives had the better antioxidant activity as the reaction processed.

Abstract:Gynostemma pentaphyllum is known as "Southern Ginseng".It contains triterpenoid saponins of the dammarane-type structure with the same skeleton of ginsenosides.In this manuscript,the saponin components of Gynostemma pentaphyllum were analyzed by HPLC,which choosed the concentration of ethanol extraction,and it was found that that adopted to the extract gypenosides(GYP) was from 75 % ethanol,polar gypenosides(GYP1) from 45% ethanol,and lower polar gypenosides(GYP 2) from 90% ethanol.Furthermore,the optimum extraction parameters for GYP 1 and GYP 2 were studied by Orthogonal method and listed as follows: GYP 1 was extracted with thirty fold-weight 45 % enthanol in 70 ℃ water bath for 12 h,and GYP 2 was extracted with thirty fold-weight 90% ethanol in 60 ℃ water bath for 6 h.Anti-hepatoma activity was determined tests by MTT and the results showed that GYP and GYP 2 can inhibit hepatoma cell SMCC7721 with IC 50 value 165.83 ±14.12 μg/mL and 113.97 ±9.26 μg/mL,respectively.However,GYP 1 without any anticancer activity.The result showed that Gynostemma pentaphyllum exhibited the anti-hepatoma activity caused by lower polar saponins.

Abstract:To optimize the technology of Purifing nostoc commune vauch polysaccharide by yeast fermenting,The effect of PH on the content of polysaccharide was researched.The additive number of yeast,the additive amount of sucrose,the temperature and the time of fermenting were designed as one-factors,and it’s orthogonal test were optimized.The best purifying technology was that the PH of fermentation liquor was 5 ±0.5,the additive number of yeast was 0.4 mg/mL,the additive amount of sucrose was 40 mg/mL,the temperature was 35 ℃,the time of fermenting was 8 h.The polysaccharide content and it’s antioxidant activity was not reduced in the extraction before and after,but the purity increased from 27.56% to 75.38%.The technology of purifing nostoc commune vauch polysaccharide by yeast fermentation is simple and feasible.

Abstract:Glutathione peroxidase(GSH-Px) is the regulator for spontaneously arise intracellular or was controlled by enzymatic reaction.It responses to the body’s ability to scavenge oxygen free radicals,and it contains important significance in resources development.The activity of Glutathione peroxidases were detected with dlrectly-determined method in eggplant,cayenne pepper,love apple,Irish potato,medlar of Solanaceae plants.The results showed that,the activities of the enzyme in the tuber of Irish potato and the fructification and root of eggplant were higher than that of the others,which will lay a foundation for the research of the enzyme in future.

Abstract:In this manuscript,Monascus HQ-3 was used as the experimental strains to produce esterase by the solid-fermentation.The effect of nutrient substances addition on the esterase production were investigated.The result show that glucose used as rapidly-efficient carbon source and fresh yeast lysate as nitrogen source for esterase production.After 4 d fermentation,the esterification force was 1.30 times higher than that of the control group.It had certain effect to improve esterification force by adding appropriate amount of lactic acid et al material,which was obviously by adding ethanol.

Abstract:Conjugated linoleic acids(CLA) are the positional and geometric isomers of linoleic acid,among them,9 c,11t-CLA and 10 t,12 c-CLA exhibited the stronger biological activity.In this study,a method was developed for the quantitative determination of 9 c,11t-CLA and 10 t,12 c-CLA by capillary gas chromatography.The sample of CLA oil was methylated with KOH in methanol.The calculation of results was carried out with external standards.The recovery of 9c,11tCLA and,10 t,12 c-CLA was between 97.66% ～103.51%,96.12% ～102.48%,respectively.The detection and quantitation limits were separately 2.4 mg/kg and 8 mg/kg.