In this research,a novel chromatographic analysis method is established to analyze polycyclic aromatic hydrocarbons（PAHs）in smoking meat products by combining solid-phase extraction technology（SPE）with high performance liquid chromatography（HPLC）,aiming to overcome the defects in general method detecting PAHs in smoking meat products analysis such as:solvent toxicity,bio-hazard.this method is proved to meet the basic demand of PAHs analysis and possesses high recovery rate,less-time cost,good repeatability and feasibility.By using SPE to pre-treat for smoking meat products,then using diode array detecter（PDA）to detect the PAHs in the sample,the result showed that this method is feasible,exact and precise.The conclusions in this paper were mainly as follow:（1）In this thesis,used commercial SPE column,filling with C18,Florisil,alkali aluminum oxide and silica gel,by comparing the recovery rate of the four absorbent,the recovery rate of C18is 80.7%～100.5%,the other three absorbent is 24.2～58.4%,20.5～52.5%,10.6～39.4%respectively. The total absorbent rate of C18to sixteen PAHs is 98.2%.and the tatal absorbent rate of other three SPE columns to sixteen PAHs is 54.7%、48.9%、37.2%respectively.The coefficienr of variation of the four SPE columns is 1.17%～3.07%、0.63%～3.02%、1.09%～3.12%respectively.So,C18 column have more rxtraction effect for PAHs in smoking meat products.（2）When using C18pole to pre-treat the PAHs,the eluting effects among dichloromethane, methanol,acetonitrile and tetrahydrofuran have been compared.The recycle rate is 85.0%～98.7%、15.9%～87.9%、56.0%～77.3%、11.0%～39.3%respectively.So the dichloromethane have most eluting effect for PAHs in C18,and the eluting effect of tetrahydrofuran is the poorest.The volume of elute is 10 ml.（3）The operating condition of chromatogram has been optimized.The chromatogram pole is Hypersil BDS 250mm×4.6mm×5um C18reversed phase High-efficiency Liquid Chromatography column.The mobile phase is acetonitrile and water,The detector is PDA;the quantificational wavelength is 254 nm,;the velocity of flow is 1.0mL/min;the volume of injection sample is 20μl; the temperature of pillar is 30℃.when the range concention is 0.01～2μg/mL,the correlation coefficient is 0.9962～0.9997,The all relative standard deviation is less than 1%.（5）The feasibility of SPE-HPLC method are validated by standard appending 60ng/mL, 100ng/mL,and 1μg/mL respectively in smoking meat products,in this way,when the concentration is 60ng/mL,the recovery rate is between 69.5%and 95.4%,correlation coefficient is between 2.1% and 4.1%;when the concentration is 100ng/mL,the recovery is between 70.8%and 97.4%, correlation coefficient is 1.4%to 4.8%;and when the concentration is 1μg/mL,the recovery is 77.2% to 102.5%,correlation coefficient is 1.6%to 4.0%,Based on those experiment results,showed that the exact,precise and sensitive of the method of soxhlet extraction,cyclohexane extraction and SPE-HPLC can meet the PAHs in smoking meat products analytical demand.（6）The analysis of the PAHs in smoking meat products:Using the method of SPE-HPLC to detect the PAHs in smoking pig’s meat products,the results showed that 15 kinds of PAHs have been detected in the sample from GUIZHOU,the kinds of PAHs was less in the sample from CHONGQING,many mixed apex have been detected in the sample from SICHUAN and HUNAN,which would absorbed other substance in fumigate process.In the 16 samples,the content of naphthalene was high,account for 29.46%of the total contention of its,fluorene and phenanthrene accounted for 11.67%and 11.16%respectively.Considering the structure of the PAHs, the three-ring PAHs accounted for 44.7%of the total PAHs,and the two-ring PAHs was second which accounted for 27.7%.The analysis to five carcinogenic PAHs,showed that the average content of benzo[g,h,i]anthracene was the highest,which is 0.99125μg/kg,dibenz[a,h]anthracene was second,which is 0.895625μg/kg,benzo[a]pyrene was lowest,which is O.019375μg/kg,all lower the regulated the most content 5μg/kg by china,and lower contention of benzo[a]pyrene 1μg/kg which is regulated lowest standard in meat products by foreign countries.Using the method of SPE-HPLC to detect the PAHs in smoking banger’s meat products also, which came from four different area in CHONGQING.In smoking banger meat products,fourteen kinds of PAHs have detected.In the four samples,the content of naphthalene was high,account for 28.9%,benza[a]anthracene and benza[b]fluoranthene can detected in three samples,and their average content is 1.065μg/kg and 0.22μg/kg respectively.Only one smoking banger meat products contained benzo[a]pyrene,its content is 0.024μg/kg,all lower the regulated the most content 5μg/ kg by china.
Post about "HPLC"
Penicillin G （PG） is a widely used antibiotic and also serves as an important raw material for semisynthetic penicillins. During traditional physical solvent extraction of PG from filtered broth , the lost of PG are considerable at pH values of 1.8-2.2. A low temperature of 0 to 5℃must be applied and expensive centrifugal extractors are necessary for the phase separation in extraction. Liquid membranes （LM） technical is a alternative which can combine extraction and back-extraction processes in one step. With the the advantages of high mass transfer efficiency and good selectivity, liquid membrane has become one of the most advantageous techniques in the purification and separation biochemical products such as penicillin G.In this work, Bulk liquid membrane （BLM） and a new liquid membrane, named hollow fiber renewal liquid membrane （HFRLM ） were applied to study the separation of penicillin G. The following achivedment were gotten in this work:A HPLC method for penicillin G determination in its solvent extraction process was established. 0.2 mol·L-1 KH2PO4 （pH=3.5）–methanol （38:62） was chose as the mobile phase. The method is rapid, accurate and reliable and the influence of buffer and organic solvents can be omitted. Several kinds of extractants were used to study the extraction behavior with different pH, temperature, carrier content, diluent. The patition coefficients of physical extraction processes was higher but considerable PG were lost. Reactive extraction process can be conducted under mild pH （5-7） and room temperature.Bulk liquid membrane experiment was performed to testify the feasibility and advantages of liquid membrane in penicillin G separation. The effects of operation mode, flow rate, carrier concentration, pH on the mass transfer performance of HFRLM were determined. The pH difference between the feed and strip is the main driving force during the mass transfer process of penicillin G.HFRLM has both good extraction and concentration efficiencies for penicillin G. The extraction in the feed reached 99.2% and the recovery in the strip was 92.2% in the circulated experiments with a initial concentration of 50000 u. During the simulated process with HFRLM to separate high concentration （100000 u） feed, the recovery of penicillin G can reach above 88% after 8 stages HFRLM operation.
According to the strain breeding theory,L-lactic acid producing mutantsadapting to fermentation of surcose and cane molasses are selected and breeded by applying ultraviolet light to mutagenize R3038.The studies mainlyon determination of contents of fermentation broth,breeding mutants, the optimal germ and fermentation culture medium and fermentation conditionsof mutants, as well as on the treatment of cane molasses.1.Malic acid and fumaric acid are the byproducts of lactic acid fermentationby Rhizopus oryzae,so it’s essential to determine the contents in broth quickly and accurately,then the fermentation and product quality can be controlled.Lactic acid Determining conditions of HPLC and HS-GC are studied.Also the condition of lactic acid isomers quantitative separation by HS-GC based on L-menthol as a chiral derivation.2.The L-lactic acid concentration can achieved 79.18g/L fermented from sucrose compared to 31.53g/L fermented from cane molasses by Rhizopus oryzae 3038 provided by China Center of Industrial Culture Collection.After mutagenizing R3038 repeatly by ultraviolet light,mutants R3038-7 and R-7 were gained.The concentration of L-lactic acid achieved 90.58g/L fermented from sucrose by R3038-7 and 52.16g/L fermented from cane molasses by R-7,the yield was increaced 14% and 65% respectively.In the broth ,99% of lactic acid produced was L-form.3.The optimal preculture medium for sucrose fermentation and production medium for cane molasses fermentation were developed by orthogonal design theory; The optimal production medium for sucrose fermentation is developed by Response surface analysis,The optimal culture conditions were confirmed by single factor experiments.（1）The optimal sucrose preculture medium（g/L）:glucose 60.0,urea 2.0, KH2PO4 0.2,MgSO4·7H2O 0.25,ZnSO4·7H2O 0.008.The optimal culture conditions:30℃,200r/min,loading 30mL in 250mL flask,10.0g/L CaCO3 was added to control the pH of broth,time of the germ growing: 12h;The optimalproduction medium（g/L）:sucrose 150,urea 2.2,KH2PO4 0.6,MgSO4·7H2O 0.25,ZnSO4·7H2O 0.008g/L,bagasse 1.5g;The optimal fermentation conditions:30℃,200r/min,loading 50mL in 250mL flask,70.0g CaCO3 was added to control pH of the broth, 10% preculture was inoculated.On the optimal conditions,the concentration of L-lactic acid produced in flask was 114.9 7g/L.（2） The optimal cane molasses preculture medium:sucrose in the mol- asses 50.0g/L,NH4NO30.4g/L,ZnSO4·7H2O 0.008g/L.The optimal culture conditions:30℃,200r/mm,loading 30mL in 250mL flask,10.0g/L CaCO3 was added to control the pH of broth,time of the germ growing:12h;The optimalproduction medium:sucrose in the molasses 80.0g/L,NH4NO30.6g/L, ZnSO4·7H2O 0.008g/L, bagasse 1.5g;The optimal fermentation conditions:30℃,200r/min, loading 50mL in 250mL flask,70.0g CaCO3 was added to control pH of the broth, 10% preculture was inoculated.On the optimal con ditions,the conc-entration of L-lactic acid produced in flask was 69.76g/L. 4.As the complex contents,high impurities,and some deleterious substancerestrain the fermentation of Rhizopus oryzae for L-lactic acid,cane molasses must be treated.The optimal treatment condition was confirmed after treating by different methods:H2SO4+active carbon+yellow potassium ferrocyanide+ NaHSO3.The L-lactic acid concentration of fermentation brothwas increaced from 52.34g/L to 61.88g/L with the treated cane molasses,the yield was increaced 18%.
The two cornerstones in tetrapyrrolic macrocycle systems are porphyrins and tetraazaporphyrins (also called as porphyrazines), which include phthalocyanines. As porphyrins and phthalocyanines, porphyrazines have a closely fused macrocyclic skeleton with an extendedly, delocalizedly conjugated macrocyclicπ-system and high stabilities for heat and light, acid-resistance, base-resistance and excellent performance of electron etc., and having more and more attracted considerable attention from scientists of many fields. Especially, metal-porphyrazines now display an extensively applicable prospects for degrading toxic organic pollutants in the wastewater by mimicking the oxidative characteristics of iron-containing oxygenase enzymes under mild conditions.According to the principle of crystallography, Unsymmetrical substance often represents some especial properties. Many literatures reported that the catalytic activity of unsymmetrical and low symmetrical molecules was better than the one of symmetrical. We synthesized the low symmetrical metalloporphyrazines from prepared intermediate of 2,3-dithiolate-1,4-dithiin, 1,3-diiminoisoindoline, 4-nitrophthalic nitrile and 4-pentyloxy- phthalic nitrile, based on having realized the synthesis of tetra(1,4-dithiin) tetra-pophyrazine (FePz(dtn)4). We successfully also separated the 1,4-dithiin-4-pentyloxy phenyl-porphyrazine, a novel and diffluent complex, by column chromatogram.The thesis mainly consists of four sections as follows:1. Progress on phthalocyannie, porphyrazines and dissymmetrical porphyrazines was introduced. Their synthesis routes, separating methods and prospects of the application were systemally reviewed. Herein, the idea and sinification for studying on the topic were also raised.2. The first low symmetrical metalloporphyrazines, iron(II) di(1,4-dithiin) diphenyl- porphyrazine, was synthesized by the template method using 2,3-dithiolate-1,4-dithiin and 1,3-diimino-isoindoline (logogram: FePcPz(dtn)n) as precursors. Then the product was modified by chloridizing for improving disolubilitiy and analyzed for the type of the composition by HPLC.3. The second low symmetrical porphyrazines, iron(II) di(1,4-dithiin)-di(4-nitrylphenyl) porphyrazine, was synthesized by the template method using 2,3-dithiolate-1,4-dithiin and 4-Nitrophthalonitrile (logogram: FePc(NO2)nPz(dtn)n) as precursors. The above compound was characterized by UV-vis, FT-IR, etc. Then the compound was separated by semi-preparative HPLC.4. A novel and soluble low symmetrical porphyrazine, magnisum or iron tri(1,4-dithiin)- (4- pentyloxy-phenyl) porphyrazine, was introduced. Based on the experience of synthesizing the above two compounds, we first displaced the nitryl of the 4-nitrophthalic nitrile by a large group–pentyloxy to form the precursor 4-pentyloxy phthalic nitrile. Then the 4-pentyloxy-phthalic nitrile react with 2,3-dinitrile-1,4-dithiin in a large amount-of-reactant ratio (1:10 mol/mol) in the Mg(OC4H9)2 solvent. The single object product was gained by using the column chromatograph filled with silica gel and characterized by UV-vis, FT-IR, 1HNMR and EA. Finally, the solubility and catalyse capability of the complex was explored roughly.
PEAs is widely used in plastic container and can enhance the toughness and plastic property of plastic and decrease the machining temperature. It is usually the sticky liquid or low melting point solid of high boiling point and hard-volatile, which does not react with plastic in common. Therefore, it can resolve in the alcohol or grease in the food when the plastic contacts with them. DEP, DBP, and DOP are in common use, which were used to believed harmless. However, they have been shown harm to human body as environmental hormone. In our country, DEP, DBP, and DOP have been recorded in the list of contaminating the environment, which can result in the atrophy of spermary and the decreace of sperm of rat and are poisonous to the embryo and anti-male hormone active. In order to understand the contamination extend of PEAs in the food packagings, the work takes DEP, DBP, and DOP as objects, focusing on the actuality of contamination of PEAs, studying in the following steps:1.Classifying the food with plastic sold in the market, enriching and puring with home-made Florisil-SPE, we analyse the fix quantify and nature of DEP, DBP, and DOP in the food with plastic packaging with HLPC and LC-MS. We established pretreatment method with different samples and method of determining the PEAs in food with plastic packaging, combining with HLPC, and filtering the proper solid phase extraction column fitted to determine the PAEs in the food, reviewing the effect of temperature, mobile phaseconstitution to the DEP, DBP, and DOP, optimizing the eluent under gradient and reaction time and other measuring conditions. Furthermore, we erected kinds of pretreatment methods combining with HLPC to determining the content of PAEs in food with plastic packaging. The results showed that the food with plastic packaging sold in the market are contaminated by PAEs to some extent, more than reported in the literature. The results of classic GC-MS and LC-MS shows that the outcome of the new methods is credibility and high sensitive, and the methods can be used to determine the contents of many PAEs at the same tine and fitted for quarantine department to determine the content of PAEs.2.We erected the method of determining the packaging bag of milk and transferred amount in water-solubility and grease-solubility liquor of plastic barrel of cooking oil with HLPC and the method of determining the content of DEP, DBP, and DOP in the ham by dissolve- deposition method. The water-solubility liquor, grease-solubilityliquor and n-Hexane are enriched and detected, then deposited for 5 and 10 days to determine. After that, we analyzed the difference of transferred amount of DEP, DBP, and DOP in the plastic in the food liquor by time. Dissolve- deposition method with HLPC, which takes Tetrahydrofuran as the solvent, methanol as the precipitator, can separate the DEP, DBP, and DOP from the packaging material of ham and then determine the content of them with HLPC.3.Attempting the improved LPME to determine the sample.LPME is the new pretreatment method which combines the merits of LLE and SPME and the pretreatment object needs to be a little organic extraction liquor and equipments are simple, the operations are easy with the cost is low. LPME technique is fitted for the object which is hard to resolve in the water and is novel as a pretreatment method in the water sample pretreatment technique. The method in this paper is to form the droplet on the needlepoint, which is difficult to be stable, we ameliorate the equipments of the LPME by covering the topwith a tube. Thus the droplet becomes. We enriching the DEP, DBP, and DOP in water with this method and determine the content of them with HLPC. We also revoewd the effects of different extraction liquor, extraction conditions and measuring conditions to the results.
With the grave concern of pollution and eutrophication degree of fresh water, algal bloom has become more and more serious. The potent toxin microcystin is frequently released during cyanobacterial blooms in eutrophic waters and may impose a risk to human health and environment. The usual microcystins in China are MC-RR and MC-LR. This thesis discusses microcystins’retention characteristic and isolation conditions by using High Performance Liquid Chromatography, and optimizes parts of the analysis steps. Taking water sample during the eutrophication period in Taihu lake, it optimizes the conditions of extracting and isolating microcystins. It also focuses on the photo degradation of microcystins by irradiation with various pigments, such as chlorophyll a,β-carrotene and mixed pigment in cyanobacteria cells. This thesis discusses the influences of pigment concentrations, temperatures, intensities and pH to the photo degradation.The determination conditions of HPLC are as follows: Mobile phase: acetonitrile-water-TFA(35:65:0.05); flow rate:0.8 ml/min; UV detection wavelength:239 nm; injection volume: 10μl. It is found that the concentration of MC-LR and MC-RR are 0.30 mg/L and 1.16 mg/L in the Taihu lake in June,2007, it is far over the limitation regulated by WHO.The efficiency of extraction and purification is much better when eluting with 70% methanol from SPE-C18 and extracting with 50% methanol.After irritation with fluorescent lamp, the results show as follows: Under the temperature of 30℃, 4320μmol/m2·s light intensity and MC-LR concentration of 5 mg/L, with pigments concentration of 0.5 mg/ml, the half-life of MC-LR is 1 hour . Different pigment solutions have different catalytic effects during photo degradation, results show that the mixed pigments in Cyanobacteria cells have a better catalytic effect than the bought pigments. MC-LR degradation is also more favorable in alkaline environment, when temperature increases, the rate of photo degradation will also becomes faster. Under the conditions of pH 9 and temperature of 40℃, the degradation rate of MC-LR reaches 7.735μg/h. In addition, the light intensity also has an effect on photo degradation, the higher the light intensity is, the faster the photo degradation reaction gets.
Luteolin is a flavone compound with many bioactivities and high percent in the peanut shell. In this paper, luteolin was extracted from peanut shell with ethanol, the extraction process was optimized; then products were separated and purified with many methods; and the antimicrobial activities of EP-1 and EP-2 were studied. The main results were as follows:1. Under the same conditions, the order of the luteolin’s yield was reflux extraction>MAE >ultrasonic extraction: the purity of product from the reflux extraction was 9.85%, while MAE was 15.18%, so the optimum process was determined: microwave power 900W, ethanol concentration 80%, extaction time 70s, ratio of solid to liquid 1:20.2. Peak area method of HPLC was used to determine the purity and components of different products. The results showed that acetic ester extraction enriched the water soluble components, and water deposition could notablely reduce their percents in the products; absolute ethanol dissolution of the dry extract enriched luteolin and another fat-soluble substance; products with high purity could be gotten by TLC.3. The products gotten from loaded-eluted with 30% ethanol on macroporous resin AB-8 had the higher purity and the same with 70% ethanol; loading sample with absolute ethanol showed the largest processing capacity and the target compound was mainly in the part eluted by 70% ethanol; the optimum process of purification using macroporous resin AB-8 was loading sample with absolute ethanol, then eluted with grads and the part eluted by 70% ethanol were fractionally collected.4. EP-1 showed inhibiting or killing effect on the test strains in different degree, and a wide antimicrobial spectrum. In the experiment, the antimicrobial effect was better on the bacterial than on the epiphyte. There was a positive correlation between antimicrobial activity of EP-1 and luteolin concentration and action time. With the same action time, the higher of luteolin concentration, the higher its antimicrobial activity was; with the same concentration of luteolin, the longer of action period, the higher of inhibiting rate on the test strains.5. With the same concentration, EP-2 showed higher antimicrobial activity than EP-1, sorbic acid and sodium nitrite, and had the antimicrobial characteristics of phenols. Synergism effect was found between EP-2 and sodium nitrite on inhibiting the growth of S.ceverce, but not on Staphylococcus aureus26003 and Bacillus subtilis63501. There is no significant synergism effect between EP-2 and sorbic acid on the tested strains. Culture temperature and pH influenced the antimicrobial activities of EP-2 on the test strains.6. The shape of bacterial treated by drug was characterized by microscope, it showed that the structure and function of outer membrane and cell walls were destroyed, and many cell fragments appeared, transportation of nutrition into the cell was prevented, then cell plasmolysis appeared, causing cellular content leakage that led to the antimicrobial effect.
Study on Extraction, Abstraction, Purification and Bacteriostatic Effect in Vitro of Alkaloids from Chelidonium
Greater celandine（Chelidonium majusL） is the Papaveraceae chelidonium plant,the alias is wintergreen barberry root,the mountain watermelon.It is grown in the mountain valley moist region,nearby the edge of forest drainage,widely distributed in the Eurasia,places such as North America,mainly distributes in our country in Northeast,North China numerous provinces and so on,the natural resource is extremely rich and abundance.It is first recorded for medicinal purposes in jiu huang ben cao.The crude drug with cool-natured, bitter in taste,slightly poisonous,enters into heart,kidney,liver and lung meridian.The main effective component in Greater celandine is the remarkable biological activity alkaloids material,it including the alkaloid 0.97～1.87%in the entire grass,containing alkaloid 1.9～4.14%in the root. So far it is already accumulated the reported that Greater celandine included twenty-nine kinds of alkaloids belonged to type of benzophenanthrene,gen tropine,bisisoquinoline and aporphines.According to modern pharmacological research,the important active constituent is the type of isoquinoline alkaloid,mainly for chelidonine,chelerythrine,sanguinarin and so on.So far,study on monomer abstraction from Greater celandine deeply,discovered that until now the alkaloid extraction process and the content determination method study report are few about Greater celandine. It is really micro studying on the common bacterial disease of livestock and fowl among the numerous pharmacologicalactions of different extraction from Greater celandine.According to the above,this article study on each committed step for new veterinary medicine,including the alkaloid extraction,concentrates,the purification and the pharmacological action research,to provide some basic theory for a large-scale industry.First,research on the technical of alkaloid extraction,this thesis the assay method of assay method with RP-HPLC determination.Using the orthogonal experimental designed method,taken the evaluating target by the extracting weight and the chelidonine content,analyzed by software SPSS14.0,inspected two kind of alcohol extraction process which are the hot dipping and the ultrasonic wave method When take the extracting weight as goal material,the extraction efficiency of hot lixiviated method surpasses the ultrasonic wave extraction process,and the difference achieves extremely obviously.The condition is 65%alcohol、ratio dosage liquor 1:20,extract temperature 80℃,extract time 2h.When take chelidonine as goal material,the extraction efficiency of the ultrasonic wave extraction process surpasses the hot lixiviated method,and the difference achieves extremely obviously.The condition is 95%alcohol,the ratio of dosage liquor 1:10,the extraction temperature 50℃,extraction time 0.5h,the extraction frequency were 85Hz.Second,study on the method of Concentration.The thesis investigated the adsorption effect of chelidonine with six kind of common maeroporous resin.Respectively type of D101 and AB-8 which are made in china,type of HP-20,HP-2MG,sp-700,sp-850 which are made in Japan.Bolting the most suitable type macroporous resin for purifying chelidonine sp-700.It is prominent of this kind of macroporous resin,first processing and the regeneration are easy.The new resin uses 30BV95%alcohol processing can be used,the extract after crossed the resin can dry easily.After the HPLC examination,mixed peak have been reduced obviously.Third,study on separation and purification.we applied with the classic the traditional Chinese medicine chemistry means to reserach the chemical constituents of Greater celandine.The method of silica gel normal phase column chromatography has been taken,elution system of petroleum benzin and acetone, trichlormethane and MeOH are be used.Obtained two monomer compound,one is accredited chelidonine by MS,1HNMR,13C NMR,IR chromatograph appraisal.Fourth,study on antibacterial effect in vitro of alkaloids from Chelidonium.Choosing the six common pathogenic bacterium,which are Escherichia coli ATCC25922,Staphylococcus aureus ATCC25923, Staphylococcus aureus persister,streptoc ATCC55121 salmonella,Escherichia coli persister,to obtain the six kinds of extraction MIC value.Method of the six different extraction MIC value are:90%alcohol elute the AB-8,60%alcohol to elute the AB-8,the chloroform extraction,the water decoctum extraction,the water level extraction,the n-butanol level extraction.By flat plate double dilution to determin the MIC,the 90% alcohol to elute the AB-8 to Escherichia coli ATCC25922 is 7.8125 mg/mL,Escherichia coli persister 15.625mg/mL.The 60%alcohol to elute the AB-8 to Escherichia coli ATCC25922 is 7.8125mg/mL,Staphylococcus aureus ATCC25923 is 15.625mg/mL,Staphylococcus aureus persister is 31.25mg/mL.Escherichia coli persister is 15.625mg/mL.The medicine MIC value of the chloroform extraction to Escherichia coli ATCC25922,Staphylococcus aureus ATCC25923,Escherichia coli persister is 7.8125 mg/mL,15.625mg/mL,31.25mg/mL,15.625 mg/mL.The medicine MIC value of the water decoctum extraction to Staphyloco ccus aureus ATCC25923,Staphylococcus aureus persister is 7.8125 mg/mL,31.25 mg/mL respectively.
Carotenoids are yellow, orange,and red pigments which are widely distributed in nature. Lycopene is one of the major carotenoids and its functions include strong quenching of singlet oxygen,involvement in cancer prevention,and enhancement of immune responses.Saccharomyces cerevisiae has clear genetic background,The cell contains lycopene precursors and can be easily applied in the food industry, In the field of the lycopene transgenic research. Saccharomyces cerevisiae has many advantages and get more and more attentions and applications.At present,the carotenoids synzymes that used in transgenic saccharomycetic are all from bacterium and fungus.And the carotenoids synzymes in our study are from Gentiana lutea.They are phytoene carotenoids synzymes psy,phytoene carotenoids dehydrogenase pds and zds. Our Lab constructed three plasmids YCp22-Gal-psy YEplac195-pds,YEplac181-zds,and transformed in S. cerevisiae w303.The resultant yeast strains accumulated lycopene in the cells at 60μg/g （dry weight） of cells. This was considered to be a result of the carbon flow into ergosterol biosynthesis being partially redirected to the nonendogenous pathway for carotenoid production.In this study, the culture medium of Saccharomyces cerevisiae positive transformant is researched. By the study of rapidly available nitrogen resource, slowly available nitrogen resource,organic nitrogen resource,metal ion,validity and concentration of intermediate metabolites,8 factors, glucose, saccharose, peptone, yeast powder, sodium malate, sodium citrate, FeSO4 and MgSO4 brings positive effect to the production of lycopene. L2738 orthogonal experiment of the 8 factors with 3 levels is launched, and the optimal medium for fermentation contains 2.4% glucose, 1.2% saccharose, 1.07% peptone,0.35% yeast powder,0.04% sodium malate,0.06% sodium citrate,0.01% FeSO4 and 0.015% MgSO4. It increases the production of lycopene by 60%. The purpose of screening is achieved primarily.
The growth of contaminated microorganisms that lead to the spoilage product has been become the great barrier for producer during processing,transportation and preservation,and the meat safety was the most attention problem for consumer.Biogenic amines are toxic substances and can be used as an quality index of foods.We can enhance and improve the quality and safety of foods by investigating the relationship between changes of biogenic amines and storage time in meat products.This article optimized the method for determination of biogenic amines by reverse phase-high performance liquid chromatogram in chilled pork.On the basis of the method,the changes of biogenic amines in chilled pork stored in different temperatures and temperature fluctuation were analyzed and relations with traditional quality index were also studyed.The main results are as follows:The method of simultaneously detecting the contents of biogenic amines in chilled pork by RP-HPLC was developed in Chapter one.Samples were extracted by 0.4 mol/L HClO4,and then derived using dansyl chloride.The mobile phase was a gradient elution program with a binary mixture of acetonitrile and water.The flow rate was 1mL/min. Fluorescence detector was applied with Ex 340nm and Em 515nm.Results show a good separation of eight biogenic amines（tryptamine、β-phenylethylamine、putrescine、cadaverine、histamine、tyramine、spermidine、spermine） within 25 min.It is linear over the range of concentrations between 0.5 and 20μg/mL（R2＞0.99）.The average recovery ranged from 82.43%to 97.14%for all amines.The RSDs were less than 10%.Changes of biogenic amines during storage in different temperatures（3±1℃and 8±1℃） and relations with other quality index were studied.Pearson correlation coefficient was used to analyze the correlation between different indexes.The results showed that higher temperature（8±1℃） may accelerate the growth of microorganisms during constant temperature storage.Tryptamine,putrescine,cadaverine,tyramine have significant relations with total aerobic bacterial counts,pH and TVBN（P＜0.01）.The content of cadaverine was higher than putrescine.The relations between biogenic amines and traditional quality index were further studied in fluctuated temperature.The results showed that the content of Tryptamine, putrescine,cadaverine,tyramine have significant relations with total aerobic bacterial counts,pH,and TVBN（P＜0.01）.