In this experiment,wheat germ globulin was fractionated,and the physicochemical and structural properties of the main fraction of wheat germ globulin were comprehensively studied. The results of experiments showed that 8S globulin is the major fraction of wheat germ globulin. Reduced SDS-PAGE revealed that wheat germ 8S globulin has two predominant bands (55.0 kD and 38.0～40.0 kD). It has a relatively high level of glutamic acid,arginine,aspartic acid and leucine,whereas cystine and methionine are lacking. CD spectra indicated that wheat germ 8S globulin is a protein rich in β-sheet structure (54.9 %),followed by random coil (25.3 %) and α-helical (19.8 %) structure.

Objective:The mechanism of interaction between additives especially polysaccharide gums and sweet potato starch(SPS) in the production of its noodles was investigated in order to provide a theory foundation on improving the quality of sweet potato starch noodles(SPSN).Method:Combining the assay of the glass transition temperature by differential scanning calorimetry,determination of leaching amylose amount and interaction between additives and sweet potato starch and infrared spectrum analysis of mixture systems,the mechanism of interaction between additives and sweet potato starch was studied.Result:These mixture systems contained CMC,carrageenan and SPS were incompatible,while those mixture systems contained alum,salt,soybean protein,glycerol,other polysaccharide gums and SPS were compatible.The mixture systems contained KGM,ASK and SPS were more steady than others.Additives combined with amylose in SPS.These interactions were strong or weak.The NaCl can weaken slightly the interactions between polysaccharide gums and SPS,while carbamid can weaken strongly their interactions.The-OH peaks in these infrared spectrum peaks of SPSN contained additives were displaced and other peaks were not displaced compared with the original SPSN.Conclusion:It was found out that the mechanism of interaction between KGM,ASK and SPS was described as follows:the mixture system contained KGM,ASK and SPS was compatible.There was no new functional group in this mixture system.Their amylose and exterior chains in amylopectin juxtaposed each other by hydrogen bond,which existed inner and exterior chains,and then form minicrystal zone,which acted as junctures.The net in mixture system was held together by countless junctures so that sweet potato starch gel contained KGM and ASK,thushad a strong texture.The interaction between SPS and alum mainly was static electricity.

In order to prevent potato from generating brownness during preservation and processing,the effects of 4-halobenzoic acids(4-fluorobenzoic acid,4-chlorobenzoic acid,4-bromobenzoic acid) on the inhibitory effects on the activity of potato polyphenol oxidase(PPO),the key enzyme to browning,have been studied.The results showed that 4-halobenzoic acids can strongly inhibit the activity of potato PPO to lose 50%,the values of IC50,the concentrations of these three inhibitors which lead the activity of potato PPO are determined to be 0.635,0.370 and 0.300 mmol/L,respectively.Kinetic analyses showed that the inhibition mechanism of all three 4-halobenzoic acids are reversible and belong to be noncompetitive inhibition,with the inhibition constants(KI=KIS)determined as:0.632,0.365 and 0.303 mmol/L,respectively.For these three inhibitors,the inhibition potency is in the following order:4-bromobenzoic acid > 4-chlorobenzoic acid > 4-fluorobenzoic acid.This indicated that the inhibitory efficiency on the enzyme is affected by the block of space of the substituted groups.

The QCA is coupled to BSA as an immunogen by the method of EDC,as well,the coating antigen(QCA-OVA) were produced by the method of MA.The immunogen and coating antigen have been identified by the method of ultraviolet full wavelength scanner.Polyclonal antibodies against QCA have been raised in four rabbits and purified by using a saturated ammonium sulfate method.The sensitivity and cross-reactivity of polyclonal antibody have been demonstrated in ELISA test.The results showed that the QCA antiserum have a very high degree of sensitivity and specificity.

The procedure to obtain oligopeptide with soybean protein isolate by sequential treatment with two proteinases was described.The experiment were designed:technique one(T1) kept optimum pH of proteinaseⅠfor 3h by adding NaOH,technique two(T2) kept optimum pH of proteinaseⅠonly at first 30 minutes and hydrolysate are immediately hydrolyzed by proteinaseⅡon acid and neutral condition respectively.The results showed that protein recovery rate are 86.5 %,87.8 % and acid soluble nitrogen rate are 83.2 %,86.4 % and ash contents are 11.1% and 7.0% respectively.The molecular weight distribution of peptides obtained by T1 above 5000,about 3000 and between 500 and 600 are 20.6%,3.3% and 61.3% respectively;The molecular weight distribution of peptides obtained by T2 above 5000,about 2000 and between 700 and 900 are 12.8%,5.7% and 71.3% respectively.It showed that hydrolysis condition of T2 is better than T1’s.

Isolation and purification and molecular characteristic of a myrosinase,which was isolated and purified from the extraction by ammonium sulfate,DEAE-52 and Sephadex G-100 chromatography were studied.The recovery and activity of myrosinase was determined during isolation and purification.By DEAE-52 and Sephadex G-100 chromatography,an active peak was recovered.Molecular weight of the enzyme was about 105000 as assayed by gel filtration of Sephadex G-100.This enzyme exhibited one absorption maximum in the ultraviolet range at 277.3 nm.The enzyme contained free thiol.The amino acid compositions analysis indicated that high Leu and Gly content and low Cys and Lys content.

Proteolysis and denaturation of porcine proteins on heating were investigated.Porcine muscles were heated to different end internal temperatures(EIT,40 ℃,50 ℃,60 ℃,70 ℃,80 ℃,90 ℃,98 ℃) for 0,10 and 20 min,respectively.Sodium dodecyl sulphate polyacrylamide gel electrophoresis(SDS-PAGE) was used to qualitatively assess the proteolysis and denatur-ation in sarcoplasmic and myofibrillar proteins of porcine muscles prepared by different heating methods.The results showed that the soluble sarcoplasmic proteins substantially decreased with increasing cooking temperature,whereas the soluble myofibrillar proteins increased below 60 ℃ and then reduced from 60 ℃ to 98 ℃.Two components of titin(34 kD and 37 kD) were thermostable proteins,the G-actin(43 kD) was less thermostable,and heavy chains of myosin degraded up to 60 ℃.Therefore EIT could be determined through the patterns of lanes by SDS-PAGE.On the other hand,different muscles of porcine were heated by various cooking methods(steam,pan fry,deep fry,baking,microwave and boiling),then the proteolysis and denaturation in sarcoplasmic and myofibrillar proteins of porcine muscles were investigated by SDS-PAGE.The results revealed that heating methods effected the proteolytic and denatural rate of porcine proteins significantly with microwave the fastest and deep fry the slowest.

The freshwater crabs(Sinopotamon henanense) were exposed with 100 mg/L Cu(as CuSO4·5H2O) to induce synthesizing of metallothionein(MT).Then the crabs were dissected and the hepatopancreas were taken out,homogenized and centrifugalized.The supernatant obtained were purified primarily using acetone precipitation(50 %～80 %),followed by chromatography treatment on columns Sephadex G-50 and DEAE sepharose fast flow,then dialyzed to desalt.According to SDS-PAGE analysis,UV absorbance spectrometry analysis and mass spectrometry analysis,high purity MT is obtained,and its molecular weight is 6882 D.

The contents of antioxidant components in seven kinds of orange juices were assayed with the contont of VC ranges from 390.6 to 478.6 mg/L,of polyphenols from 573.1 to 655.0 mg/L of carotenoids from 5.47 to 7.25 mg/L and of limonoids from 0.10 to 0.17 mg/L.The TEAC values determined by ABTS/K2S2O8 system are from 4.79 to 6.09,with blood orange the highest and Jincheng the lowest.The relationship between TEAC values and the content of VC shows remarkable level(r = 0.868,p=0.011),and that between TEAC and polyphenols is significant(r=0.909,p=0.003),while there is no obvious correlationship between the TEAC and carotenoids(p>0.1).It was concluded that the polyphenols are probably the dominant antioxidant component in these seven kinds of oranges.

This experiment studied dynamic de-adsorption technology of total saposins from Cornus officinalis in HPD-300 macroporous resin by single factor tests and orthogonal test designs.The optimal manipulation conditions were ascertained by variance analyses.The results showed that the optimum desorption conditions are:flowing rate 1.0 BV/h,volume 2.2 BV,and desorption time 2.2 h;The best desorption conditions by alcohol are 50% concentration,flowing rate 2.0 BV/h,and desoprtion volume 4.5 BV.

The effect of chitosan on gel properties was investigated.Gel hardness and water holding capability were assay together with the analysis of the microstructure of the gels and scanning electron microscopy.The results showed that chitosan could enhance the gel hardness and water holding capability.IR spectra studies indicated that the main interaction between gel and SSMP is electrostatic attraction force.

The purpose of this study is to evaluate the correlations among the size,the morphology,the associated protein content of wheat starch granule and the thermal properties of 8 different wheat starches.The relationships between the micro-structural morphology and thermal properties of wheat starch granule were qualitatively analyzed DSC(differential scanning calorimeter) and SEM(scanning electron microscope)were used.SPSS13.0 was applied to analyze the data.The results showed that the negative correlations between DA(diameter of starch granule type A) and DB(diameter of starch granule type B),also those between DB and thermal properties(onset temperature(To),peak temperature(Tp),enthalpy(ΔH) and range of gelatinisation(Tc-To)),are revealed.Significant positive correlations between DA and thermal properties,also between Tp and ΔH,are observed;the content of the associated protein is significantly and negatively correlated to the DB,whereas weakly and negatively to the DA.

Total phenolic content and antioxidant activity of methanol,hexane,chloroform,ethyl acetate and aqueous extracts of Phyllostachys pubescens were evaluated respectively.The ethyl acetate extract had the highest amount of phenolic compounds.It also exhibited the highest antioxidant activity by the 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2’-azinobis(3-ethylbenzothiazoline-6-sulphonic acid(ABTS) methods.The antioxidant activity of extracts are correlated with it containing of phenolic compounds significantly.GC-MS analysis indicated that ethyl acetate extract contained a variety of phenolic compounds.HPLC analysis showed that pyrogallol was the predominant phenolic compound in this extract.

Objective:To extract polysaccharide from Citrus suavissima and analyze its effect of cleaning oxygen radical.Method:The polysaccharide was extracted with hot water at 100 ℃ and precipitated by alcohol.The protein in the extractions was removed by the sevage method.Test were also done with the extraction material,including the determination of sugar,the analysis of polysaccharide behaviour,and the determination of the activities of cleaning oxygen racial.Result:the extraction ratio was 1.55%,and its total sugar content was 52.07 %.IR showed the absorption peak of sugar.In the determination of the activities of cleaning O2· and ·OH,its IC50 was 880 μg/ml and 1280 μg/ml respectively.Conclusion:CSPS has the effect of cleaning oxygen radical.Its activity is positively relative with dosage in certain range.

Isolation of porcine serum IgG by polyphosphate was investigated.The optimal parameters for IgG isolation were determined as follows:the polyphosphate concentration 0.1%(W/V),pH 3.9,and temperature 45 ℃.The recovery rate and purity of extracted IgG are respectively 60.9 % and 64.5 %,and the immunological activity preservation rate is 87.3 % under optimal conditions.The polyphosphate isolation technics is applicable to food industry.

Molecular imprinting technique(MIT) is a technique to produce molecular recognition polymer materials with high selectivity and affinity.Polymerization occurrs between monomers and cross linker around a template.After removing template polymer with molecular memory to the template is obtained.It has been used in the fields of analytical chemistry,catalysis and organic synthesis.In this study,the effects of template molecule,functuional monomer,cross linking agent,and solvent on the preparation of imprinting polymer were studied.By ultra-violet absorption spectroscopy mutulaction between template molecule and functional monomer was analyzed,and selection and combination mechanism of polymer was predicted.

The Maillard reaction products(MRPs) were prepared using L-lysine and DMaillard reaction.The pH value and absorbance of the Maillard reaction products(MRPs) were determined.In this research,the antioxidative activities of MRPs,including iron-chelation activity,scavenging effect on superoxide anion radical and DPPH· radical,and reducing power were studied.The results showed that browning and acidity increased with the heating time;the wavelength of maximal absorbance was about 460 nm;While reaching the same browing degree,namely absorbance 2.2,their reaction speeds were shown as follows:1:2>1:1>2:1.Three kinds of MRPs with different proportions of amido and carbonyl exhibited good iron-chelation activities and scavenging activities against superoxide anion radical and DPPH· radical,but they almost did not have reducing powers.

The properties of waxy rice starch,waxy corn starch,potato starch,common corn starch and their hydroxypropylated starch were studied in this experiment.The results showed that the paste viscosity,clarity,cold storage stability,freeze-thaw stability,iodine and starch color reaction and whiteness among these starches vary significantly after being hydroxypropylated.It also showed that the onset of viscosity increase occurs is shorter and iodine color reaction of hydroxypropylated starches can be lowered in comparison with its native starches,while the paste clarity,cold storage stability and freeze-thaw stability become higher than its native starches.

The crude water-soluble polysaccharides from Chaenomeles cathayensis fruits were isolated with hot water extraction followed by ethanol precipitation.The polysaccharides were deproteinized using Sevag method,decolorized by macroporous resin and then dialyzed.The fine water-soluble Chaenomeles cathayensis polysaccharides(CCP) were obtained and further fraction-ated to elute for the component CCP1 by anion exchange column chromatography on DEAE-cellulose.The purity of CCP1 was examined by gel filtration chromatography of Sepharose Cl-6B.The purified polysaccharide CCP1 was proved to be homoge-neous by HPGPC and its molecular weight(MW) was 2.879×106 D.Analysis of monosaccharide composition by HPLC indicated that CCP1 consists of rhamnose,arabinose,fructose,mannitose,glucose and their molar ratio is 0.034:0.228:0.045:0.055:0.638.The main fraction CCP1 was subjected to the complement-fixation experiment.CCP1 expressed some anti-complementary activity in vitro and dosage-effect relationship between them existing.

The complexation reactions of myricetin(Myr) and β-cyclodextrin with its derivatives were studied by spectrophotofluorimetry.The results indicated that β-cyclodextrin(β-CD) and its derivatives could notably enhance the fluorescence intensity of myricetin.As the concentration of β-CDs increases,the fluorescence intensity increases and maximum emission peak shifts towards long wave.Hildebrand-Benesi equation showed that the inclusion complexe was formed at the ratio of Myr:CD=1:1.The complexation ability of β-CDs is as following order:HP-β-CD >HE-β-CD > DM-β-CD >β-CD.The complexation reactions are also studied by thermodynamics.The parameters of ΔG and ΔH are negative value,and ΔS is a negative or small positive value.This indicates that the complexation reactions release heat and happen spontaneously.Driving force of complexation reaction results from the change of heat content change of recognition within molecules.

The derivative of olaquindox,called as OLA-SH,was synthesized by succinic anhydride method in this study.And OLA-SH is identified by TLC,MS,IR spectrum and NMR spectrum.Then two artificial antigens of olaquindox(OLA-BSA,OLA-OVA) were prepared by active ester method(AE) and mixed anhydride method(MA) respectively.The characterization of hapten-protein conjugates were examined by two methods,ultraviolet spectrophotometry,sodium dodecyl sulfate polyacry-lamide gel electrophoresis respectively.The numbers of hapten molecules per molecule of protein estimated by ultraviolet spectrophotometry according to the absorbance of compounds at 259.4 nm for two conjugates were 3.8 and 5.0 respectively.

Soybean proteins were prepared from the model systems consisting of lipid-reduced soybean proteins and different levels of linoleic acid(LA) and lipoxygenase.The interactions of soybean proteins and oxidizing linoleic acid catalyzed by lipoxygenase were assayed by fluorescence spectroscopy and soluble protein hydrophobicity.The fluorescence of the oxidized samples showed excitation and emission maxima at 350nm and 440 nm respectively.The fluorescent compounds were partially soluble in the organic layer of the chloroform-methanol(2:1,V/V).The solution fluorescence showed an excitation maximum at 350 nm and an emission maximum at 430 nm,and the intensity increased with reaction time.The interactions of soybean proteins and oxidizing linoleic acid catalyzed by lipoxygenase also resulted in decreases of soluble protein hydrophobicity.With an antioxidant(BHT) addition,the changes in fluorescence and soluble protein hydrophobicity were inhibited.

Objective:In order to detect the antibacterial activity of a plant extract using a simple and fast colormetric detection method and identify those plant extracts with bioactivity.Methods:Firstly to set up a plant extract library and develop an antimicrobial colormetric detection method.Then,the plant extracts were tested for antibacterial activity against two species of bacteria,S.mutans and A.actinomycestemcomitans.Results:A group of plants extract with high antibacterial activity were discovered.Conclusion:The colormetric detection method can be used to screen a large plant extract library due to its fast and simple procedure.

The effects of UV lights(UV-C and UV-B)on the radiation of resveratrol in the harvested grape peelings were examined.The resveratrol content was analyzed by HPLC.The results showed that UV-B has little effects on the content of resveratrol in grape peelings,whereas maximum resveratrol content(15-fold higher than untreated grapes) is achieved when irradiated 20 min with UV-C with 48 h darkness treatment.Therefore,the controlled UV-C irradiation pulses are useful as a simple postharvest treatment to obtain possible" functional" grapes with a dietary source of high resveratrol content.

This study explored the effects of the kinds of ferrous salts,hydrolysis time,co-incubation time,mass ratio,reaction pH and temperature on the chelating activity of casein hydrolysate with ferrous salt,in order to prepare some basic data for preparation of a product rich in bio-iron.Peptides produced by enzyme hydrolysis of casein reacted with Fe2+.Results showed that the chelating activity of FeSO4 with casein hydrolysate was significantly higher than that of(NH4)2Fe(SO4)2 and FeCl2(p <0.05).The chelating activity of casein hydrolysate obtained at different hydrolysis time differed,and when hydrolysis time 7 h was the best.When the co-incubation time of casein hydrolysate and FeSO4,mass ratio,reaction pH and temperature were 10 min,1:2,6.0 and 40 ℃ respectively,the chelating effect was optimum.

The changes of pH,TBA,peroxide value,acidity value,Aw,moisture content and microbial property were studied during the processing of Sichuan bacon in this study.The results of physical chemical property showed that the lowest pH were about 5.9,TBA,peroxide value and acidity value increased gradually,Aw were about 0.7 as were as moisture content were about 20% in final products.The results of microbial property showed that the predominant microorganisms in Sichuan bacon were Lactobacillus and Staphylococcus.The results provided reliable basis for controlling the industrialization fermented processing of bacon as were as improving quality of bacon.

With the raw material for filming like soy protein isolated,added with plasticizer like glycerin and reducing agent like sodium sulfite,the soy protein isolated film was made.The technology and reference data of laboratory and industrialized manufacturer on soy protein isolated film were studied in this article.The results showed that the technology and reference data of laboratory manufacture on soy protein isolated film are:water dissolving of soy protein isolated,heating,meanwhile stirring in the oar way with the speed of 180 r/min,antifoaming the film liquid by adding 0.06 % edible antifoaming agent,spreading film on the staingless steel board coated with 0.05 ml/100 cm2 Tween 80,drying for 2 hours under the hot wind of 60 ℃,drenching with water evenly,taking off the film and keeping in reserve.The technology and reference data of industrialized manufacture on soy protein isolated film are:water dissolving soy protein isolated in double layer pot,heating it,meanwhile stirring with the speed of 30 r/min,filming on the red copper belt and its speed 1.5 r/min,then ventilating water vapor to heat up dryer,with vapor pressure 0.25 MPa(surface pressure),rolling up the film,packaging and storing.This technology has been tested successfully and can be applied in expanding production.

Polysulfone(PSF)-Fe3O4 composite ultrafiltration membrane was made by phase-inversion process.SEM,AFM showed that most particles distributing uniformly in the membrane and the mean surface roughness(RMS) was only 46.059 nm in the range of the scan areas 30μm×30μm.The puerarin and troxerutin ultrafiltration with the PSF-Fe3O4 composite membrane in different magnetic intensities were performed respectively.The change current of permeation with the intensity were different.In the puerarin ultrafiltration test,the permeation got to maximum in 0.2 T while in the troxerutin test,the permeation got to maximum in 0.4 T.The difference proves the novel idea that different objects can be separated with only a composite membrane in turn by controlling the magnetic field doable.

In this experiment,enzymatic hydrolysis of animal protein was studied.The main task was to find out the optimal degree of hydrolysis(DH) of hydrolyzed animal protein(HAP) according to the flavor of Maillard reaction products(MRPs) which was used as a standard of estimation with DH as characteristic parameter for HAP,the substrate of Mail lard reaction.And the optimal technological parameters are:papain,temperature 55 ℃,pH 6.0,and 4 hours,E/S 5000 U/g for chicken pone paste.The paper reported the contents of essential nutrients,amino acid and free fatty acid though studies on mashed chicken-bone.By automatic amino acid analyzer and gas chromatograph-mass spectrometer amino acid and fatty acid were detected.As a result,there are affluent calcium,phosphorus,iron,zincum,and some proteins and low-content fats in mashed chicken-bone.It contains seventeen free amino acids and human essential isoleucine,leucine,methionine,phenylalanine,threonine,valine etc.eight amino acid of high content and reasonable proportion,and also it contains five free fatty acids with human essential linolenic acid and linolic acid.

In order to make full use of agricultural waste material—citrus peel,ultrasonic wave-assisted extraction technique of total flavonoids from citrus peel was studied according to a current,rotational and combinational design of quadratic regression.Then,one quadratic regression model for the total flavonoids yield was established.The extraction conditions were optimized by the above model,while the optimized results were verified by experiments.Results showed that the pH value has a very significant effect on the extraction rate of total flavonoids.The ethanol concentration,ratio of solution to material,interaction between time and ethanol concentration,and time and pH value show significant effects on the extraction rate.Other factors have no significant effects on the extraction rate.Research results indicated that the optimized extraction conditions for maximum yield of total flavonoids are:pH value 5.6,ethanol concentration 75%,ratio of solution to material 26 ml/g,and extraction time 80 min.Under the optimized conditions,the experimental value of yield is 3.314%±0.063%(n=3),close to the estimated value 3.348449% attained by regression model.The model for the total flavonoids yield have better prediction effects.

With beer yeast waster as the raw material,the important effect factors such as among ratio of material to water,time,temperature and dosage of acetic acid were confirmed by the single factor tests primarily,then according to the Box-Benhnken center combined experimental design principles,the 3 most important effect factors were analyzed with RSM.The optimum conditions were obtained as follows:ratio of material and water 1:4,temperature 43.6 ℃,dosage of acetic acid 3.5%,and time 5.5 h.Under these conditions,the content of GSH red reach over 29%.

The PSF-500 of polysulfone membrane with a molecular weight cut-off(MWCO) of 50000 had the best effect on purification of flavonoids from leaves of Dendrocalamus latiflorus by ultrafiltration(UF) in contrast with five other membranes.The yield of flavonoids is 4.29 % and the content is 44.123 %.The effects of filtration pressure,feed velocity of flow and runtime on the operation were tested and discussed.The results showed that the best parameters on the operation were filtration pressure 0.20～0.30 MPa,feed velocity of flow 0.4 m/s and runtime 12 h(the PSF-500 membrane must be cleaned after 12 h).At the same time,the recovery test of adding rutin was experimented with PSF-500 in UF system.The results indicated that average recovery is 97.0% and coefficient of variation is 1.94%.

Oil in water nanoemulsions containing β-carotene were produced by high pressure homogenization under 100/10 MPa.The effects of four different emulsifiers(Tween 20,Tween 40,Tween 60,and Tween 80) on the stability and properties of nanoemulsions were investigated.With the variance of the ΔBS(t) of the nanoemulsion,the particle size and its polydistribution index of β-carotene nanopartical,the concentration of β-carotene during storage experiment,Tween 20 with a 10 %(W/W) concentration provided a smaller particle size(d=132 nm) and narrower distribution(PdI=0.214),and it also had a higher retention amount(64%～78%) of β-carotene after different temperature storage conditions for 28 days.

Inulin hydrolysis catalyzed with strong acidic cation resins as solid acid was studied.A high fructose syrup with high quality was obtained after being vacuum concentrated.The optimal conditions for inulin hydrolysis are:D061 strongly acidic cation resin as solid acid,the ratio of solid acid to inulin solution(20%) 1:3,hydrolysis temperature 75 ℃ and hydrolysis time 120 min.Hydrolysis rate of inulin with this method is 92.1%.Desalting from inulin solution is one of the key technologies for continuous inulin hydrolysis with solid acid.

It was studied that the processing of submerged fermentation pork with the Pediococcus acidilactici.MRS medium containing CaCO3 medium was used in activating Pediococcus acidilactici.It was studied that effects of concentration of NaCl and NaNO2,inoculation volume,fermentation time and temperature on pH.The optimum conditions of pork fermentation were found to be that NaCl 2.5 %,sodium nitrite concentration 0.012 %,inoculation volume 3.5 %,21 h,30 ℃ by orthogonal test.The taste of the fermented pork was good by the technology,and microbiological and NaNO2 indicators were in line with quality standards.The result was satisfactory.

The process of preparing of collagen peptide from pig skin by papain was studied.The factors of affecting process of hydrolysis were investigated.By determining the hydrolysis degree of collagen protein(the ratio of the peptide bonds eleavaged /total peptide bonds in protein),it could be concluded that the best conditions for the hydrolysis of pig skin were:pH 5,hydrolyzing temperature 60 ℃,ratio of papain 0.9 %,concentration of substrate 30% and total hydrolysis time 4 h.Under these conditions the hydrolysis degree of collagen protein could reach 14.91%.

A ternary microemulsion system which was composed of propolis,water and Tween 80,and the influence that lactic acid and sucrose ester affect on propolis microemulsion were studied.When the proportion of propolis and tween ranges from 1:5 ～ 1:7 there can be a clear and steady microemulsion system.

The natural plant extracts have inhibitory effects against pathogenic bacteria of post-harvest fruits and vegetables.It is validated that Flos Caryophlli extract can significantly inhibit the main low-temperature pathogenic bacterium Botrytis gray of post-harvest grape.Extraction of antibacterial ingredients from Flos Caryophlli by ultrasonic was studied.Using single factor and orthogonal design,the effects of solvent selection,solvent concentration,material to solvent ratio,ultrasonic temperature,ultrasonic power,and time on Flos Caryophlli extracts with growth rate method determining antibacterial rate.The results showed that on the conditions of 80% ethanol as extraction solvent,material to ethanol ratio 1:15,temperature 55 ℃,ultrasonic power 210 W,and time 60 min,the antibacterial activity of extracts reached the highest.

To obtain chemical constituents from the fruit of Catalpa ovata G.Don,the methods of water extraction,ethanol extraction and petroleum ether extraction were used.Protein,amino acid,carbohydrate were tested in the water extracts.Phenol,flavonoid anthraquinone,terpenoid,cardiac glycoside,alkaloid were tested in the ethanol extracts.Alkaloid was found in the acid extracts.Petroleum extracts contained the terpenoid.

In this research,brewer yeast submerged fermentation for bioaccumulation of Se and Cr was studied according to its super ability of bioaccumulation of trace elements.The effect of bioaccumulation factors including time,inoculation amount,inorganic salts were all studied.The optimal fermented conditions were worked out through orthogonal design L9(34).The results of optimization were Se(Ⅳ) 20μg/ml,Cr(Ⅲ) 40μg/ml,inocuation 15 %,and culture time 48 h.And the yeast enriched with Se and Cr were obtained under the optimal condtions.

In this study,the natural and safe inhibitors applied to lemon dryslices was studied.It showed that the most effective inhibitor combinations for controlling the browning of lemon dryslices based on orthogonal test are 0.25% L-cysteine+0.20% Cinnamic acid+0.50% EDTA-2Na,and the selected combination can inhibit the browning of lemon dryslices significantly.

Effects of different pretreatment methods such as heating treatment,adding NaHSO3 or NaCl or CaCl2 on preservation rate of vitamin C(VC) in preserved fruit of cherry tomato were studied in this research.Results indicated that the four pretreatment processes had different effects on VC stability,and the order was:adding NaCl>adding CaC12>adding NaHSO3 >heating treatment.On the conditions of soaking in 0.2% citric acid and 1.5% NaCl compound solution for 15 min,the preservation rate of VC in preserved fruit of cherry tomato reached maximum,45.83%.

For the full use of freshwater fish resource and evaluation of its added value,oil was extracted from Ctenopharyngodon idellus Viscera in vacuum environment.Then the oil was refined by degumming,depickling,bleaching and deodorization.With POV and TBARS as the analysis index,the antioxidations of VC,VE,BHT and PG to the oil were investigated.The optimal refinement conditions for the oil obtained were as follows:degelatinization by adding 50% H3PO4 accounting for 1% of the oil;disacidify by adding 3.65% caustic soda accounting for 1.5% of the oil;decolorisation by adding activate carbon and activate clay with the proportion of 1:20,and amount added accounting for 2.1% of the oil;and deodorization for 60 min at 0.085 kPa degree of vacuum.The capability order of antioxidation is:0.01%PG > 0.02% BHT > 0.1% VE > 0.2% VE > 0.2% VC.

The peel essential oil of Xuefeng honeyorange were extracted by supercritical CO2 fluid extraction at different extract pressure,extract time and extract temperature(20 MPa,1 h,30 ℃;30 MPa,1.5 h,30 ℃;30 MPa,1 h,40 ℃).The components of essential oil were isolated and identified by gas chromatography-mass spectrography after the essential oil and pigment were separated.Result from this experiment showed that 22 kinds of components of the sample were identified at 20 MPa,1 h,30 ℃,and 21 kinds of components of the sample were identified at 30 MPa,1.5 h,30 ℃ and 30 MPa,1h,40 ℃.The study confirmed chemical components of the essential oil and extraction condition have the relevance.For example,the contents of beta-pinene and nerol of the essential oil were increased while temperature were elevated,and the contents of the calarene of the essential oil were increased while pressure were elevated.

Peptides derived from TSP-I was separated by ultra-filtration technology,the effects of pressure,temperature and concentration of peptides on ultra-filtration permeate flux,permeate increment and membrane efficiency.The results showed that the optimum conditions are:5% TSP-I,pressure 28 Psi and time 40 min.Under the condition,ultra-filtration permeate flux is 9.98 LHM,ultra-filtration permeate increment is 2.68 g/10min and membrane efficiency is 3.41 g/m2·min.The capacities on scavenging O2·,·OH,DPPH·and H2O2 of VC and TSP-II were investigated by spectrophotometry.Study informed that TSP-II had a certain extent antioxidation,the order of scavenging ability is H2O2>·OH >O·2>DPPH·.On scavenging H2O2,0.80 mg/ml TSP-II is equivalent to 0.03 mg/ml VC.

The optimum conditions about sequentially hydrolyzing small black-soybean protein isolated were:the small black-soybean were hydrolyzed by alkaline proteinases in the condition of pH 9.0,50 ℃ for 4 hours,and then,hydrolyzed continuously by neutral protease in the condition of pH7.0,50 ℃ for 4 hours,and the quantity of pronase is 4000U/g.The peptide yield reached 80%,and the degree of hydrolysis(DH) of black-soybean protein isolate is 32.75%.The result of gel chromatography showed that the percentage of the component of black-soybean peptides with a molecular weight below 10000 D 91.61 %.

In this study,the extraction technology of bone protein of pig was studied.At first the fat was removed by petroleum ether with the method of reflux at low temperature.Then the bone protein of pig was extracted after decalcification and alkali treatment.This experiment investgated the influence of decalcification conditions on the result and the optimum conditions of extraction was determined.The experimental results indicated that the best acid dipping condition is hydrochloric acid concentration 0.72 mol/L,solid-liquid ratio 1:10 and dipping time 8 h.And the optimum conditions of extraction are extraction time 7 h,matter to solvent =1:8,pH value 4,and temperature 100℃.

The processing technology optimization based on sensory evaluation and oil content of fried cake was studied.The effects of marinating time,content of soybean,water content of semi-product,frying temperature and frying time on the quality of fried cake were investigated.The results showed that the optimization were as follows:marinating time 6 hours,content of soybean 12.5%,water content of semi-product controlled about 55.5% and frying time 2 min at 190 ℃.In these conditions,the fried cake obtained the highest score with low oil content of 17.23%.

Using Porphyra yezoensis as the raw material,single factor and orthogonal tests were conducted to obtain the optimum conditions of synchronous ultrasonic-assisted extraction of polysaccharide and phycobiliprotein.The results showed that the optimum conditions are ultrasonic power 880 W,ultrasonic time 60 min,water extracting temperature 30℃ for 4 hours,and ratio of solid-liquid 1:50.Using the optimum conditions,the extraction percent of polysaccharide and phycobiliprotein is respectively 34.03% and 1.2%,and phycoerythrin purity is 0.356.

Production and characteristics of twoβ-glucosidase strains,Aspergillus niger M85 and its mutant obtained by soft X-ray Nk,synchrotron irradiation were studied.The results showed that the nutrient demands,culture condition,β-glucosidase production kinetics and properties of the mutant strain are distinctively changed in comparison with the original strain M85.The spectrum of nitrogen sources of the mutant has been broadened and the demand of KH2PO4 reduced from 0.2% to 0.1%.The mutant was addicted to enough oxygen.The fermentation kinetics test showed that fermentation cycle of the mutant is shortened by 16 hours and the β-glucosidase activity is raised about 80%.The optimal temperature and pH for the mutant β-glucosidase reaction are shifted from 60 ℃ to 50 ℃ and from 4.0 to 5.0,respectively.

Silk sericin was prepared from silkworm Bombyx mori and silk sericin hydrolysates(SSH) were obtained by hydrolysis of silk sericin with six proteases.It’s ability to scavenge 1,1-diphenyl-2-picrylhydrazyl(DPPH) radicals was determined.The antioxidant activities of the SSH,including lipid peroxidation in linoleic acid system,reducing power and ferrous ion chelating ability,were evaluated.The results showed that different protease hydrolysates possessed different ability to quench the ABTS cation radicals and DPPH radicals.Among those tested,Alcalase hydrolysate exhibits the highest scavenging activity than other protease(p<0.05).The results also showed that six SSH had potent antioxidative activity on peroxidation of linoleic acid.Alcalase hydrolysate exerted the highest inhibition than other protease(p<0.05).The reducing power and ferrous ion chelating ability of six SSH were significant.These results indicated that six SSH from silkworm Bombyx mori were natural antioxidant with potent antioxidative activity.

The technique of hydrolysis of soybean isoflavones by β-glycosidas"eAmano"was studied in this study.The different influencing factors during the process of enzyme hydrolysis were studied through single factor tests.The reaction conditions of hydrolysis by β-glycosidas"eAmano" were optimized through orthogonal test.The optimal reaction conditions of hydrolysis of daidzin were:time 140 min,the concentration of enzyme 33μg/ml,pH 4.5,temperature 50 ℃.The optimal reaction conditions of hydrolysis of genistin were:time 140 min,the concentration of enzyme 33μg/ml,pH 4.5,temperature 60 ℃.The identified test proved the hydrolysis ratio of daidzin attained 98.2% and the hydrolysis ratio of genistin attained 94.2% under the optimal conditions.

Medium ingredients for neutral proteinase(NPR) production of B.subtilis CNMC-0014 was optimized using stastically-based experimental designs. A single-factor experiment(SFE) method was adopted to choose the carbon and nitrogen sources significantly influcing NPR biosynthesis. Among the six variables of carbon sources we studied,the most significant variables were stastically elucidated for optimization,and included glycerol and corn flour with the corresponding value of NPR of 3955.16±2.15 U/ml and 3939.15±1.87 U/ml. For nitrogen sources,the most significant variable affecting NPR production was soybean flour with maximun NPR production of 4318.12±5.66 U/ml. The optimum concentration of each significant variable was then determined by range analysis (RA) and analysis of variance (ANOVA),the optimun values for the critical nutrients supplements for the maximun NPR production were 2% of corn flour,1% of glycerol,3% of soybean flour and 3% of bran,with the maximun NPR activity of 4526.28 U/ml. Results,statistically,indicated that the influences of clycerol and corn flour on NPR prodoction were significant at 5 % (p<0.05) level,but,the effect of soybean flour was most significant at 1 % (p<0.01) and bran had no significant influence (p>0.05) on NPR production. And meanwhile,the effects of metal ions,dissoluble oxygen (DO),initial pH,strain ages and inoculum sizes on NPR production were also investigated. Resulsts shown that Ca2+,Mg2+,Na+,Zn+,Mn2+ could activate enzyme biosynthesis at different levels,especially Ca2+ with a maximun activity of 4552.97 U/ml. And whenas,Fe3+,Fe2+,K+,Ag+ had strongly inhibitory influence on NPR production,particularly Ag+ (NPR activity was only 987.46 U/ml).The most suitable filled amount of SmF medium in 300 ml Erlenmeyer flask was 50 ml. Optimal pH was 7.5,the most suitable strain ages and inoculum sizes for maximun NPR production were 24-h-old strain and 3% culture broth,respectively.

Five strains of probiotic bacteria were fiber embeded and cultured in a continuous fibrous bed bioreactor with corn fiber as the carrier.The immobilized biomass was studied by selective culture methods.Bifidobacterium longum TQ21-2-2,Lactobacillus acidophile CICC06005,Clostridum butyric TO-A,Bacillus mesentericus TO-A and Enterococcus faecalis T-110 were found to have coexisted stably.The total biomass of five probiotics in immobilized phase was 3.5×1010 g in corn fiber of the fibrous bed bioreactor.The system can be used to obtain formulation of microecological and fiber embeded tablets,so as to produce solid high biomass commensal probiotics products continuously.The fiber and bacteria were dried into functional food tablets with probiotics biomass in the amount of 109/g,1000 times higher than that estimated in China national standard.

Mitochondria DNA of sea cucumber were extracted from the sea cucumber nutrient solution with optimized method.The quantitative and qualitative analyses of DNA solution were performed with the calculation of A260/A280,Agarose gel electrophoresis,and PCR.The results showed that our method of DNA extraction and species identification from the sea cucumber nutrient solution was more efficient and rapid than traditional methods.This study will be helpful for quicker,more economical,and dependable species identification of the sea cucumber.

To optimize the indirect enzyme-linked immunosorbent assay(ELISA) conditions based on prepared antiserum was studied.Antiserum titre was determined by ELISA methods.Optimal working concentrations of DES fold antigen and antibody were determined by phalanx method.Then the immunoreagent conditions,such as dilution,pH and incubation time and others,were optimized.Four similarities were choosed to calculate the cross-reactivity.Results showed that the dilute rate of antiserum can reach 1:102400.The optimal working concentrations of DES fold antigen and antibody by phalanx method are 1:200 and 1:4000 respectively.Standard curve is established through ELISA methods.This inhibitory curve well expresses the specificity of the antibody with good linear relationship.The value of IC50 is 1.89 ng/ml.The value of the LOD is 0.08 ng/ml.During the four similarities,the cross-reactivity is 3.1% for dienestrol while the other similarities are less than 0.1%.The immunoreagent conditions are thus optimized and the research provids appropriate method of ELISA for diethylstilbestrol assay.This can provide a base of the pack of DES ELISA kit.

Effects of five different media on examining beer spoilage bacteria were carried out.It was showed that LMDA medium is optimum.The growth of three familiar beer spoilage bacteria in the five culture media was compared.Meanwhile the effect of LMDA was validated.

Through hydrolysis by enzyme from microbial fermentation,the resveratrol yield of Polygonum cuspidatum can be increased.Four excellent strains for producing enzyme to hydrolyze Polygonum cuspidatum were screened out from several strains with indican hydrolyzation activity.The experimental results showed that compared with traditional ethanol extraction and self-enzyme hydrolysis method,the resveratrol yield of Polygonum cuspidatum can be increased obviously by hydrolysis of enzyme from Aspergillus niger 1 fermentation.

The laccase derived from Ganoderma lucidum Karst mutant G1502 was purified and characterized in enzymology.The result of polypropylene amine gelatin electrophoresis(PAGE) analysis indicated that this strain in the fermentation medium only produces single laccase.Its cultured liquid with laccase was condensed by dialyzing,and purified by DEAE-cellulose ion exchange chromatography.The enzymic purity increases 24.28 fold,and the recovery ratio of enzyme reaches 18.66%.The Km and Vmax for oxidizing guaiacol,the kinetic parameters of enzyme,are 1.94×10-4 mol/L and 2.28×10-6 mol/L·min,respectively.The activities are inhibited by Fe2+,Co2+,Ca2+,Na+ and Ba2+ and induced by K+ and Cu2+,but Cu2+ is weak inducer.

The purification method and properties of plant esterase(P-E) from soybean were studied.Results showed that the electrophoresis purity P-E can be obtained by extraction with phosphate buffer(0.3 mol/L,pH 7.0) extraction,differential centrifugation,ammonium sulfate deposition and ion-exchange chromatography.The optimal temperature,pH and Km of P-E were also determined respectively.

0.1% citric acid,malic acid,succinic acid,lactic acid,acetic acid,pyruvic acid was added to the defined medium to study their effects on cellulose production individually.The results showed that only lactic acid,acetic acid,pyruvic acid among the above organic acids could proliferate Acetobacter xylinum and enhance cellulose yield.When 0.4 % pyruvic acid added,yeild of cellulose was highest 2.02 g/L;When 0.3% lactic acid was added,yeild of cellulose was highest 2.16 g/L;When 0.4 % acetic was acid added,yeild of cellulose was highest 2.80 g/L;When 0.4% acetic acid,0.3%lactic acid and 0.4% pyruvic acid coexisted in the medium,the yeild was up to 4.45 g/L.

Angiotensin-converting enzyme(ACE) inhibitors are very important drugs for clinical treatment of hypertension.Pepsin and trypsin were used together to prepare the hydrolysates from collagen.Ultrafiltrations(UF) with 1 kD membrane and gel filtration chromatography(GFC) with Sephadex G-15 were used to separate the hydrolysates into different components.By measuring the inhibitory activity and protein concentration of the components,two samples with the greatest inhibitory activity were selected.The samples were then taken to further separate by reverse phase high performance liquid chromatography(RP-HPLC).Different components of the samples were collected.The same methods as that mentioned above were taken to screen the optimum component.After desalting and freezing drying,the molecular mass of component with the greatest inhibitory activity was determined at last.

The dextransucrase is a kind of glucosyltransferases that can catalyze the transfer of D-glucopyranosyl units by synthesizing sucrose to α-glucans or oligosaccharides.In this research,enzyme producing conditions for dextransucrase-producing organism were studied.The results showed that the optimum conditions of producing dextransucrase are as follows:most suitable carbon source 5% sucrose,cultivating time 24 h,cultivating temperature 25 ℃ and cultivating solution initial pH value 8.0。

The mycelium growth speed and the decomposition ability to starch of Cordyceps sinensis,Ganoderma lucidum HG and Ganoderma applanatumuan were compared on the flat medium.It was found that their mycelium growth speed reached 1.28 cm/d,0.64 cm/d,0.55 cm/d respectively,and the utilization ability to the starch Ganoderma lucidum and Ganoderma applanatumuan were superior to Cordyceps sinensis.The mixed culture results showed the optimum inoculation age of Cordyceps sinensis to Ganoderma lucidum HG was 3 d to 5 d,also the optimum inoculation proportion of Cordyceps sinensis to Ganoderma lucidum HG was 2:3;The best fermentation medium was tested by orthogonal design,and the the optimum nutrient ingredients combination(%):glucose 1.0,starch 2.0,soya flour 2.0,and yeast extract 0.5.on these conditions,the verification experimental results showed and the maximal biomass is 1.97 g/100 ml.

Corn flour as mixed carbonic source and bran+peptone+yeast as mixed nitrogenous source,the liquid culture medium of Phellinus linteus mycelia was optimized by orthogonal test in this study.The results showed that the optimal culture medium comprised corn flour 3%,bran 3%,glucose 3%,KH2PO4 0.3%,MgSO4·7H2O 0.15%,VB1 20μg/100 ml,VB2 30μg/100 ml,and on the culture conditions,of culture temperature 32.5 ℃,natural pH,rotation speed 130 r/min and culture cycle 192 h,the average mycelial biomass was 4.4 g/100 ml.

β-glucosidase extracted from almond was immobilized by adsorption on chitosan crosslinked with glutaraldehyde.The conditions of immobilization were achieved,when glutaraldehyde was oscillatetd and absorbed for 4 hours in the water bath:concentration 1.5 %,pH 5.5,and temperature 25 ℃.The results showed that,1 g chitosan adsorbs 5U β-glucosidase,and the rate of activity recovery is 27.34 %.

Soybean protein was hydrolyzed by alkaline protease to produce soybean peptide.Extent of reaction was expressed in terms of degree of hydrolysis.By single factor and quadratic ratation combitination genernal design hydrolysis condition model was established and the optimum hydrolyzing conditions are temperature 55 ℃,pH value 9.5,enzyme concentration was established 6 %,substrate concentration 2 %,and hydrolyzing time 1.0 hours.On these conditions,nitrogen solubility index(NSI) and degree of hydrolysis(DH) of hydrolysate are respectively 93.16 % and 92.27 %.

Polysaccharides produced by solid and liquid fermentation of Armillariella tabescens were investigated simultaneously.The polysaccharides were extract by heat extraction and freezing,their contents were assayed with phenol-sulfate method,and the dispelling alcohol effects of the polysaccharides on mouse were studied.It was found out that the polysaccharide content produced by solid fermentation reached maximum after 62 days;the polysaccharide content produced by liquid fermentation for 5 days was higher than for 8 days;Both the high-dose and low-dose Armillariella tabescens polysaccharides groups could significantly prolong mouse’s tolerant time to alcohol(p<0.05),superior to the positive control group.The resut showed that Armillariella tabescens polysaccharides could inhibit the effects of alcohol.

The bacterial flora occurring in pond water,surface mucus,gills,intestine and putrid meat of healthy tilapia cultured in freshwater,were estimated both quantitatively and qualitatively.The results showed that total viable count of bacteria in above samples respectively were 2.6×104 CFU/ml,1.0×103 CFU/cm2,2.2×103 CFU/g,1.4×105 CFU/g and 5.4×107 CFU/g.Total 353 isolates were dominated by Gram-negative bacteria.Bacillus sp.,Enterobacteriaceae sp.and Vibrionaceae sp.were predominant in pond water and fresh fish,with a small number of Pseudomonas sp,Enterococcus sp.,Staphylococcus sp.and so on;but the dominant position were changed with different samples.The bacterial flora were simple in putrid meat,Pseudomonas cepacie,Aeromonas hydrophila and Bacillus brevis were dominant spoilage organism,with a small number of Edwardsiella tarda and Kluyvera spp.In addition,GB and SN standard methods were used in detecting the pathogens on surface mucus,gills and intestine of newly-harvested tilapia,Escherichia coli,Pseudomonas aeruginosa and Streptococcus faecalis were detected,but Listeria monocytogenes,Salmonella sp.,Staphylococcus aureus,Vibrio parahaemolyticus and hemolytic streptococcus were not detected.

Technologic conditions of whey protein enzymolydrosis for calcium binding peptides production were optimized in this research.Based on the output of calcium binding peptides and content of amino nitrogen,the main factors affecting the enzymolydrosis were experimentally studied in details.Results showed that the content of amino nitrogen could reach 0.272 mg/ml under the optimal conditions of the enzymolydrosis temperature 45 ℃,the time 100 min,the whey protein concentration 7.0 %,substrate to enzyme ratio 70:1,and the solution pH 8.00.On these conditions,the strongest Ca-binding activity was obtained.

In this study,cDNA library was constructed successfully from the specie of Camellia ptilophylla Chang with a low content of caffeine through using a series of ZAP kits that bought from the company of Stratagene.The titer and recombinant rate of this library were 6.0×105pfu/ml and 97.3 % respectively,the insert size with 1.0～2.0kb occupied 70% of the whole library,matching the requirement of high quality library.The titer and recombinant rate of amplification library were 1.9×109pfu/ml and 99.1%,respectively.

In this study,a convenient liquid-liquid extraction method for sample preparation was introduced,which can enrich and purify chloramphenicol in royal jelly to a similar level compared to sample treated by solid phase extraction(SPE).This method showed no interference on the determination of chloramphenicol,and it greatly reduced the cost of sample preparation.

A rapid capillary electrophoresis method was established for detecting water-soluble vitamins in mushroom powder.Effects of buffer solution and voltage on the separation of vitamins from mushroom powder were studied.The effective ingredients of the samples were purified and enriched by means of a solid-phase extraction step with a pre-conditioned C18 cartridge,and the compounds were eluted with pH4.2 HCl solution.VB1,VB2,VB6,VC and VPP could be separated on a 50 cm ×75 μm capillary column with 20 mmol/L borate buffer solution(pH8.72),at temperature 25 ℃ and electrophoresis voltage 20 kV,within 10 min,and the satisfied results were obtained with different characteristics including linearity,precision and stability.

Objective:To explore the methods of both virus enrichment and nucleic acid extraction for establishing a Norwalk-like viruses(NL Vs) detection method by RT-PCR.Method:In this study,with poliovirus as the model to optimize glycine-PEG concentration method;The effects of 4 methods of extracting RNA from NLVs in shellfish were compared;Detection of Norwalk-like viruses in commercial shellfish samples was performed,and positive samples were demonstrated by DNA sequencing.Results:This study conducted virus enrichment with pH 9.5 glycine buffer-16% polyethylene glycol(PEG) and RNA extraction with trizol-isopropanol.The recovery of viruses was 16.8% from seeded shellfish;and the detection limit was 8.1×102 RT-PCR50/5 g shellfish.NLVs in 3 of 25 samples were found by RT-PCR and validated by DNA sequencing.Conclusion:In this study,a NLVs detection method from shellfish is established,which is sensitive and available.

A ultra performance liquid chromatography with electrospray tandem mass spectrometry(UPLC-MS-MS) method was developed for the quantitative determination of bisultap residue in raw strawberry and its processed products.The samples were extracted by methanol-water(1:1,V/V) without any purifying treatments,were separated by ACQUITY UPLC HSS T3 UPLC column with equal gradient mobile phase,and detected by electrospray tandem mass spectrometry with ES-and multiple reaction monitoring(MRM) modes.Results showed that the mean recoveries range from 65.3% to 91.5% with relative standard deviations in the range of 7.8%～11.8% when the spiked concentrations of bisultap are 0.05,0.10 and 0.20 mg/kg respectively,and the limit of detection is 3.0 μg/kg.The detection operation can be completed within 1 minute with high sensitivity and accuracy,and is suitable for the fast qualitative and quantitative detection for bisultap residue in strawberry samples.

Sialic acid in milk was released by acid hydrolysis,and then was derivated with O-pheny-lenediamine:2HCl(10mg/ml)at 80℃for 40 min.The conditions of HPLC were:Symmetry C18 column(250 mm×4.6 mm,5μm),the mobile phase 1.0% tetraphdrofuran(containing 0.2 % phosphoric acid)-acetonitrile(92:8),the flow rate 1.0ml/min,the column temperatue 35 ℃,and the detection wave length 230 nm.The results indicated that the linear rang of sialic acid was 10～320μg/ml.The average recovery was 95.7 %.The method has the characteristics of good reproducibility and high sensitivity.It can be used to determine the contents of the free and oligosaccharide-bound sialic acid in milk.

A study on effect of acidity in determination of lead in food by hydride-generation atomic fluorescence spectrometry(HG-AFS) was introduced.Instrumental and analytical conditions were optimized.The optimal acidity of the sample solution is 0.18 mol/L.The linear range of the standard curve is 5～40μg/L with the regression coefficient of 0.9999.And the detection limit of this method is found to be 0.15μg/L.The relative standard deviation(RSD) is 0.22 %.The recovery rate is between 98.3 %～104.6 %.The method has been applied to the determination of lead in starch fungi mushrooms etc with satisfactory results.

Objective:To establish HPLC method for determination of alliin in garlicinenteric-coated tablets.Method:The HPLC system consis of Zorbax C18 column(250 mm×4.6 mm,5μm) and methanol and water(30:70) as the mobile phase with the flow rate of 0.5 ml/min.The UV detection was 214 nm.Results:The standard curve is linear within the range of 0.0122～0.61 mg/ml,and the average recovery of alliin is 97.2 %.Conclusion:This method is simple,accurate and reliable for determination of alliin contents in garlicinenteric-coated tablets by HPLC.

ELISA and LC-MS/MS for the analysis of furazolidone(AOZ) residues in aquatic products were studied.Samples were derivatived with 2-nitrobenzaldehyde and extracted with ethyl acetate.When the samples were spiked with 0.60,2.00 and 6.00μg/kg of AOZ,the average recoveries are 99.2%,96.0% and 100.0% respectively by ELISA,while the relative standard deviation(RSD) is 1.8%～12.6% with detection limit of 0.3 μg/kg.The average recoveries are 90.8%,94.3% and 86.3% respectively by LC-MS/MS and RSD is 6.2%～14.3% with detection limit of 0.1μg/kg.Three positive samples analyzed by ELISA were confirmed by LC-MS/MS and no false positive samples were found.The results are basically the same.The results showed that ELISA is a rapid and exact method with good reproducibility suitable for the screen of AOZ positive samples in aquatic products.Hence LC-MS/MS is sensitive and suitable for determination of positive samples.

A method for the determination of residual carbendazim in vegetable was established by reverse phase high-performance liquid chromatography with DAD detector.The carbendazim was extracted with methanol and partitioned into methylene chloride after initial acidification and again after subsequent alkalinization and last acidification of the extract.The volume is adjusted to 10.0 ml with HCl(1+11);A RP-HPLC method was used with C8 column(5μm,250mm×4.6 mm).The flow rate was 1.0 ml/min and the detection wavelengh at 286 nm.The proposed method is accurate,precise and selective with limit of determination of 0.02 mg/kg,recovery of more than 70% and RSD of less than 10%.

The determination of furosine in royal jelly by ion-pair reversed phase liquid chromatography was carried out.The separation of furosine was accomplished on Atlantis C18 column.Acetonitrile/water(5mmol/L sodium heptane sulfonate)/formic acid(20:79.8:0.2)was used as the mobile phase.It was detected by a UV detector at 280 nm.The linear range was 0.25～50 mg/L with equation of y=0.2818x+0.0271(r=0.9997).The method detection limit of furosine was 11.9 mg/100g protein.The average recoveries was 96.94%.The method is satisfactory for determing furosine in royal jelly.

Bacillus cereus is one of the microbes which affect the quality of the raw milk.It can produce enterotoxins which cause vomiting or Diarrhea.Food poisoning which caused by Bacillus cereus happened often.Enterotoxin is harmful to the human body.We investigate microbiology pollution of the raw milk come from four cities in this research.Especially aerobic bacterial count and Bacillus cereus count were detected.The results indicated that the microbial contamination condition in raw milk is unoptimistic.At the same time,the research laid a foundation for traceability of the raw milk.

Fatty acid compositions of Fructus Hippophae pulp and seed oils respectively were identified and quantified by gas chromatography(GC)-mass spectrometry(MS).A comparative study of major fatty acids respectively extracted from pulp and seed was presented.A base-catalyzed transesterification method was used to convert fatty acids to methyl esters.Fifty-four peaks were eluted by an INNOWAX capillary column and 35 fatty acids(accounting for 99.6% of total oil) were identified by GC-MS.The components were determined by normalization method.Significant differences of the components were found between pulp and seed oils.The amount of saturated fatty acids in seed oil and pulp oil is respectively 32.54 % and 13.10% approximately 2.5 times higher than that in seed oil,while the amount of unsaturated fatty acids is respectively 66.92 % and 86.52%,the amount of monounsaturated fatty acids is respectively 53.71% and 26.05%,and the amount of polyunsaturated fatty acids is respectively 13.21% and 60.47%.It is thus an important dietary resource of functional fatty acids.

Taking space mutation treatment Cordyceps militaris and its the primitive strain as a material,determines the cordycepin and adenosine with HPLC,determines the cordyceps acid with periodic acid sodium colorimetry method.The phenol-sulphuric acid method was used in the polysaccharides content.To analysis the change of active constituent content with space mutation treatment.Cordycepin content of space mutation treatment Cordyceps militaris was 2.5 times of primitive strain.At the same time the adenosine content was enhanced 2 times,the active constituent total quantity enhanced 26.2 %.Space mutation treatment enhances the Cordyceps militaris the active constituent content.

In this study,molecular mass weight of egg white was determined by gel chromatography and Tricine-SDS-PAGE separately.Egg white peptides were enzymolysised by Alcalase and the optimal enzymolysising parameters were as follow,pH 8.0,reaction temperature 60 ℃ and enzymolysising time 60 min.The results showed that added 6mol/L urea into separation gel(T=49.5%,C=6%)was better than 10%(V/V)glycerin added.Molecular mass weight of egg white peptides which was enzymolysised was accurately determined by Tricine-SDS-PAGE electrophoresis.Linear regression coefficient(r) of marker was 0.9946,average relative error rate was 0.5% by compared with gel chromatography.Tricine-SDS-PAGE electrophoresis was a simple,fast,direct-viewing method to determine the mass weight of egg white peptides.

The fruit aroma compoenents in five peach cultivars in Gansu Province," Baifen peach"," Dajiubao","Cangfangzaosheng"," Gangshabai" an"dBeijing No.7" were extracted by SPME combined with GC-MS.The results showed that there were 33,35,43,44 and 47 aroma components respectively in five cultivars.Esters,alcohols,aldehydes,aldoketenes,alkane and alkene were the major constituents.It also was found that" Baifen peach"," Dajiubao","Cangfangzaosheng","Gangshabai" an"dBeijing No.7" had 4,4,4,7 and 6 unique components,respectively.There were 15 common aroma components in five cultivars.

The effects of two factors,the temperature in water extraction and the temperature in dry process of raw material on polysaccharide determination were investegated.Four species,Dioscorea polystachya from Henan province(Tiegun yam),D.polystachya from Yunnan Province(Kunming yam),D.alata from Zhejiang Province and D.persimilis from Fujian Province,were took as samples in this experiment and their polysaccharide contents were determined by using sulphuric acid-phenol spectrophotometric method.The results showed that the temperature in dry process of raw material had little influence while the temperature in water extraction had significant influence.The suitable temperature in water extraction should be below 65 ℃.If the temperature was high enough,it would significantly affect the result of polysaccharide determination because of dissolved starch.

Nutritional components of the muscle of wide Perca fluviatilis were tested and analyzed with routine methods in order to evaluate its nutritive value.Samples of 15 wild individuals were collected from the Ereqsi River,Xinjiang.The results showed that the contents of protein,fat and ash of the fresh muscles were 88.69%,4.69% and 6.62%,respectively.The composition of amino acids of muscle was found those to contain 18 common amino acids and 8 essential amino acids for human needs.In dry sample,the total content of amino acids was75.89%,the content of essential amino acids was 38.15%,the percentage of essential amino acids in total amino acids was 50.30%.The constitutional rate of the essential amino acids in general accorded with the FAO/WHO standard.The threonine is restrictional amino acids and the coefficient of amino acids ratio was 85.97.In dry sample,the content of four delicious amino acids was 29.40 %.The contents of EPA and DHA in fatty acids were 6.96% and 1.39%.

The volatile N-nitrosamines of 20 Rugao hams from market,detected by GC-NPD,and the detection result was confirmed by GC-MS.The results showed that 3 volatile N-nitrosamines i.e.N-nitrosodimethylamine(NDMA),N-nitrosodiethylamine(NDEA) and N-nitrosopyrrolidine are found in Rugao ham and their contents are 0.20,0.81,3.85μg /kg respectively.The detection rates of NDMA,NDEA and NPYR in Rugao ham are 85%,95% and 100% respectively.NDHA,NPIP and NDBA are not found in Rugao ham.

Objective:To analyze the Artemisia bud main active ingredient qualitatively,and study Artemisia buds on immune modulatory effects.Method:Use the herbal classic qualitative test method,the solution of different polarity after the extraction tube reaction,and determine what the active ingredients contain in the Artemisia buds largely.Use untreated mice of different doses of Artemisia bud extract after intervention by carbon clearance experiment,chicken erythrocyte immunization,concanavalin A-induced lymphocyte proliferation test,evaluation Artemisia bud regulate immune function.Results:Artemisia buds main chemical ingredients are rough alkaloids,organic acids,proteins,polysaccharides,flavonoids and other substances.Normal control group,Artemisia bud extract high dose group of mice can increase carbon clearance index(p<0.01) and phagocytic index p<0.01),suggesting Artemisia bud extract may enhance normal mouse macrophage phagocytosis.It demonstrates that Artemisia buds can enhance the mouse nonspecific immune function.The hemolysin level and the lymphocyte proliferation capacity of the intervention of middle-dose and high-dose mice is significantly higher than the control group(p<0.01).It suggested that extract of Artemisia buds can be dissolved by increasing serum hemoglobin levels and enhance lymphocyte proliferative ability to enhance the special mice heterosexual immune function.Conclusion:Artemisia bud extract can increase the non-specific immune response and specific immune response of mice,so it can enhance immune system function.

Objective:To investigate the effects of soybean isoflavone on early stage kidney injury in impaired glucosetolerance(IGT) rats induced by D-galactose(D-ga1).Methods:To make the IGT model rats by intraperitoneal injection(i.p.) D-gal for 8w.Two doses of SI(soybean isoflavone) were given intragastrically(i.g.) for 6w since the 3rd w,2h BG,BUN,MAU,LDH and LDH isoenzyme activity in every group were tested at the end of the experiment.Results:Compared with the normal control group,2h BG,MAU content and LDH activity of the model group increase obviously(p<0.05),while LDH isoenzyme activity also increases.Compared with the model group,2h BG,MAU content,LDH activity(p<0.05) while LDH isoenzyme activity of the SI group decrease significantly.Conclusion:SI could protect renal damage through improving IGT,decreasing MAU content and renal LDH activity of IGT rats,and regulating the activity of LDH isoenzyme.

Objective:By genechip cDNA microarray,the biomolecular mechanism of anti-fatigue of Pueraria flavonid was studied in the quadriceps of the exercise-training rats.Methods:SD rats were randomly divided into three groups:normal rest group(A),exercise-training group(B) and administered-drug group(C).B group and C group rats were trained with high intensity 7 weeks by treadmill.The total RNAs were isolated from the quadriceps tissue,and were purified to mRNAs by oligotex.The purified mRNA were reversely transcribed to cDNA with hybridization probes labeled by fluorescent-dUTP.The genechip was scanned for the fluorescent signals and showed differences by the computer analysis.Results:The TfR gene was down-regulated expression in the quadriceps of exercise-training rats compared with of rest rats and obviously up-regulated expression in the quadriceps of administered-drug rats compared with of exercise-training rat.Conclusion:TfR gene expression in quadriceps of the training rats is regulated by Pueraria flavonid,and its expression has an effect on fatigue and plays a role in the study of fatigue mechanism and screening anti-fatigue functional food as a sensitive gene.

Objective:To research the hepatoprotective effects of Ganoderma lucidum peptides(GLP) against D-galactosamine(D-Gal)induced liver damage in mice.Method:Mice were randomly divided into five groups,namely normal,model and three GLP-treated groups.GLP-treated groups were daily given(ig) the doses at 60,120 and 180 mg GLP /kg bw respectively.Normal and model groups simultaneously received the same amount of physiological saline for 2 weeks.Then the mice from model group and GLP-treated groups were treated with 750 mg/kg bw D-Gal(ip).Aspartate transaminase/alanine transaminase(AST/ALT) activities in serum,malondialdehyde/glutathione(MDA/GSH) levels and superoxidedismutase(SOD) activity in liver were measured by the detection kits according to the manufacturer’s protocols.The liver histopathological characters were observed under light microscopy.Results:At the dose of 180mg/kg bw GLP,the ALT/AST activities in serum and MDA lever in liver were significantly reduced,SOD activity and GSH content in liver were significantly increased(p<0.05～0.01) when compared to model group.The liver histopathological characters were close to normal groups’.Conclusion:GLP possesses potent hepatoprotective effects against D-Gal-induced liver damage in mice.

Nutritional components of the salted fish from southeast of Guizhou were analyzed and evaluated,including general nutrients,minerals and trace elements,amino acid compositions,fatty acid compositions,nitrite and heavy metals content.The results showed that the salted fish contains rich minerals and trace elements,and there were 16 kinds of amino acids in this salted fish.The ratios of essential amino acids(EAA) in total amino acids(TAA) was 46.09% and the EAA/NEAA was 85.50%,respectively.The fatty acids in the salted fish are mostly made up of unsaturated ones,and the ratio between the polyunsatu-rated and saturated ones is 5.99.In addition,the nitrite level is very low and the heavy metals such as As,Pb,Hg and Cd could not be detected in the salted fish.All results suggested that the salted fish from southeast of Guizhou is a kind of high-quality and safe food with particular flavors and high nutritional values.

Objective:To study the effect of fresh donkey’s milk on the immune function of mice,and to study the effect of fresh donkey’s milk on inhibitting the growth of Mycobacterium tuberculosis.Methods:The immunosuppressed mice induced by cyclophosphamide were administrated with fresh donkey’s milk for 20 days.The indexes of thymus and spleen,the ability of antibody secreting cell,the levels of serum hemolysin and the ability of lymphocyte transformation were measured.According to The Laboratory Science Procedure of Diagnostic Bacteriology in Tuberculosis,we study the effect of fresh donkey’s milk on inhibitting the growth of Mycobacterium tuberculosis.Results:The high dose groups of fresh donkey’s milk can enhance the ability of antibody secreting cell and the levels of serum hemolysin.The fat of fresh donkey’s milk(0.4ml,0.5ml) can inhibit the growth of Mycobacterium tuberculosis.Conclusions:The fresh donkey’s milk can enhance the immune function of mice.The fresh donkey’s milk can inhibit the growth of Mycobacterium tuberculosis in vitro.

To study the antioxidant effect in vivo of polysaccharide from moso bamboo leaves(PMBL) on aging mice,in order to provide theoretical basis for the utilization and exploitation of moso bamboo leaves.Aging mices were randomly divided into PMBL group(stomach irritation with PMBL) and normal group(stomach irritation with saline only),contents of protein and malondiadehyde(MDA),enzyme activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH-px) and the total antioxidant competency(TAOC) in the serum,heart,liver/kidney of aging mice were measured by reagent box.Experimental results:PMBL can significantly increase the contents of protein,the total antioxidant competency(TAOC) and the activity of SOD /GSH-Px in the serum,liver/kidney,decrease the contents of MDA in the serum and the organs.The ratio of TAOC/MDA showed that TAOC/MDA of PMBL group in the serum,heart,liver/kidney is obvious higher than the normal group.The results showed that PMBL can promote portion synthesis in serum and organs,relate recession of the tissue and cytoarchitecture,improve antioxidation ability in vivo and balance the state of antioxidation/oxidation.

The effects of different storage temperature(-5 ℃,-10 ℃,-15 ℃,-20 ℃,-25 ℃) and different package methods(uncover package,vacuum package,package full of nitrogen) on squilla were evaluated by sensory method and biochemical properties including total volatile basic nitrogen(TVB-N)and K value.The result showed that the pertinence of K value and the TVB-N is obvious.When the K value below 20 % and the TVB-N below 30mg/100g,the squilla’s sensory index above the C level.Vacuum package and package full of nitrogen can inhibit the growth of bacteria and extend the shelf life.When the squilla stores at-20 ℃ and-25 ℃,the difference of sensory index and the chemistry index is no obvious.

During the process of production,pungent cabbages are easy to suffer contamination from pathogenic bacterium,furthermore,these products are edible food without heating process.Therefore,the pungent cabbages with residual pathogenic bacterium are easy to cause disease,such as dysentery.Total count of bacterium,coli group,count of lactic acid bacterium,pH and the kinds of pathogenic bacterium on the 1th,5th,8th,12th,15th,19th,22th,26th,29th and 33th day after storage were detected.Experimental results indicated that accompanying with the rise of lactic acid bacterial number,the number of pathogenic bacterium degraded.Moreover,on the 19th day,acid bacterial number was 1×105 CFU/g and the total bacterial count dropped to 1 ×104 CFU/g;on the 25th day acid bacterial number was 1×107 CFU /g,the total bacterial count<<1×104 CFU /g and there was no pathogenic bacterium,which is acid nonresistant.

In order to inquiry into the relationship between the chestnuts’ calcification occurrence and the cell wall’s metabolism,the study measured the changes of the incidence,the weight loss rate,the respiratory intensity,the water soluble pectin content,the insoluble pectin content and pectin methylesterases(PE)activity and polygalactouronase(PG) activity of the chestnuts’ calcification under different storage conditions.The results showed that during storing the larger the weightlessness of the chestnut fruit was,the more the water loss was and the higher the calcification occurrence was.The insoluble pectin,pectin methylesterases(PE),water-soluble calcium increases along with calcification degree increasing;the fruits’ weightlessness and the cell wall’s damage was the main cause of the chestnuts’ calcification.

A mold was isolated from mildewed dried beef and it was identified as an Aspergillus.This Aspergillus was then inoculated into the dried beef to determine the influence of water activity to the shelf life.The results showed that the water activity of dried beef was essential to its shelf life.

Changes of LOX and PG activities were studied on different ripe Dongzao fruits under different storage temperatures.The results showed that the progress of softening and senescence is faster in room temperature than that in cool temperature,and can be delayed but not be inhibited.Both LOX and PG took part in the progress of softening and senescence but the activity peak of LOX was related only before the launch of softening and senescence,so closely related The with the start of softening and senesdence.The LOX activity peak appeared ahead the rapid decline of fruit firmness.It thus showed that PG is involved in softening and senescence because of the marked rising of its activity during the rapid decline of fruit firmness.It belongs to the inductive enzyme.

The effect of different Na2S2O5 water-curing treatments were used to study on the post-harvest physiologic and biochemical characteristics of Zhen’an chestnut(Castanea mollissima Blume).The results indicated that Na2S2O5 water-curing treatments depressed rot,respiration intensity,decompose rate of starch and soluble protein during storage;the higher Na2S2O5 concentration,the more significantly they were depressed;because Na2S2O5 treatments depressed the decompose rate of starch and the consumption of the soluble sugar,the soluble sugar content of chestnut with Na2S2O5 treatments was lower than that of control in the early period of storage,but higher in the end.The results indicated that sodium mtabisulfite treatment could make preferable better effect on the storage of chestnut.

The effects of hydrogen peroxide on the induced disease-resistance of tomato fruits by cold-shock treatment were studied.Cold-shock treatment could induce the disease-resistance of tomato fruits,enhance the endogenous H2O2 content in the beginning of storage and increase the activity of GST.Furthermore,cold-shock could induce the activities of some anti-disease enzymes,including PAL,chitinase and β-1,3 glucanase.The inducement of H2O2 content and activity of GST could be accelerated by pretreatment with H2O2 before cold-shock,which promoted the induction of anti-disease enzyme activities.All of the inductions were inhibited by pretreatment with dimethylthiourea before cold-shock.In conclusion,the cold-shock treatment could induce the disease-resistance of postharvest tomato fruits,and hydrogen peroxide played an important role in the progress.

Effects of different concentration gibberellic acid(GA3) on postharvest lignification and quality of bamboo shoot under 4 ℃,85%～95% RH were studied in this paper.The results showed that GA3 treatment significantly inhibited the increase of lignin and fiber contents in bamboo shoot during storage,decreased the contents of H2O2 or O2 and the activities of phenylalanine ammonia Lyase(PAL) or polyphenol oxidase(PPO).It was also found that GA3 treatment retarded the increase of malondialdehyde content and kept better qualities of bamboo shoot.100mg/L GA3 was better than 50mg/L GA3.

A new fashioned nano-packing was developed for the preservation of food.The O2 and RH transmission rate of the packing decreased 2.1% and 28% compared with normal packing.Sauce beef was packed with nano-packing at room temperature for 28 days,Sensory quality,physical and chemical quality and micro indexes were analyzed to investigate the effects of nano-packing on preservation quality of sauce beef.The results showed that nano-packing could significantly inhibit the increasing of bacteria and volatile base nitrogen(VBN) of sauced beef compared with normal packing.Meanwhile,nano-packing could expand the shelf life of sauce beef,and maintain its colour and flavor.

The research progresses of extraction and activated function about yeast mannan were elaborated in this article.The extract methods such as acid extract methods,alkali extract methods,and the activated function such as enhancing immunity and regulating the balance of intestinal microflora were systematic analyzed.In addition,the open questions in mannan research were pointed out,the direction,emphasis and the tendency of mannan in the future were prospected.

In the paper,the microstructure,cell and enzyme activity of food materials during freeze drying were reviewed,and the qualities of freeze dried food due to the change of glassy state were introduced.The strategy to reduce energy consumption during freeze drying of food materials and the foreground of freeze dried food were depicted.

It is an interesting research on soybean dregs which are one of the industrial by-products with high nutritional value.The dregs nutritional and applicational value could be further enhanced by fermentation.This paper illustrated some issues about soybean dregs as follows:the functionality of fermented dregs,the application of fermented dregs in various fields and the future research trend of the fermented soybean dregs.

Preparation of the lyotropic liquid crystal template for separating and purifying natural pigment member could avoid the depuration process of samples.The request for the samples was not of a superior grade.Through the different pigment member formed different liquid crystal textures under the lyotropic liquid crystal template,natural pigment members could be separated and purified or impurities eliminated directionally.This method is one kind of high efficiency,low cost,safe operation and is a new separation purification technology suitable for the natural pigment industrialization production.This article discussed different liquid crystal textures,brought up suitable mechanism hypothesis(chemical reaction template theory and liquid crystal composition transformation physics adsorption theory)for this technology.

Microwave is widely applied in the areas of sterilization,drying and heating in food industry for its cleanness,rapid temperature elevation,and high efficiency.A discussion on security of microwave application in food industry was conducted such as principle of microwave and the effects of food ingredient microwave process.The results showed that it is safe in the mass.However,for a few secretive food ingredients,the microwave may make some insecurity.So we put forward some safety measures to microwave food.

This article introduces the importance of high-oleate peanut research,as well as the basic characteristic,structural characteristics,classification of Δ12-oleic acid desaturase,the molecular basis of the enzyme which result in high-oleate peanut traits,a ndi ts biological characteristics.

Polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE) technique has been proven to be a powerful tool for analyzing microbial communities and their dynamics changes.As a fast and reliable molecular method,DGGE is used widely to investigate the microbial component and structure of complex communities without isolation and cultivation processes.However,potential causes resulting in limitations in DGGE analysis can be sometimes met.In this paper,the principle and application aspects,as well as the limitation of DGGE techniques for microbial ecology analysis were introduced,and the main causing factors addressed and discussed,such as DNA extraction,PCR amplification,DGGE conditions optimization,and DGGE profile analysis.