猪肝超氧化物歧化酶的分离纯化与初步表征

研究猪肝SOD的分离提取、纯化以及初步表征。以猪肝为原料,通过抽提液加热、丙酮沉淀和Sephadex G-200层析柱色谱提取、纯化Cu,Zn-SOD;在单因素试验的基础上,采用L(934)设计对提取工艺进行系统优化。结果表明:经过热变性,可以除去大部分杂蛋白,提高了SOD的比活力;最佳的提取条件是:在1.4%的盐浓度下,于70℃水浴中热变性10 min,然后加1.6倍体积的丙酮获得SOD粗沉淀;溶解后的粗酶液经Sephadex G-200层析柱纯化后,经SDS-PAGE电泳检测为单一条带,HPLC检测显示为单一对称峰,均表明最终得到了高纯度的SOD;紫外-可见吸收光谱和ICP-MS分析结果均表明得到的是含铜、锌的SOD,即Cu,Zn-SOD;以邻苯三酚为底物,该酶的Km值为1.574,Vmax为0.268。     

越橘叶超氧化物歧化酶的分离纯化与定性研究

采用超声波辅助提取越橘叶超氧化物歧化酶得粗酶液,经选择性热变性、Sephadex G-75柱层析、透析、冷冻干燥,得到纯度较高的越橘叶超氧化物歧化酶。聚丙烯酰胺凝胶电泳显示在32kD和42kD左右有2条清晰条带;紫外-可见光谱扫描在波长258nm和280nm处有吸收峰;原子吸收光谱也测定出越橘叶超氧化物歧化酶中含有铁、锰、锌离子。结果表明越橘叶超氧化物歧化酶有3种类型:Fe-SOD、Mn-SOD和Cu/Zn-SOD。     

甘薯叶中SOD的分离纯化研究

通过比较几种提取的方法对纯化的倍数和酶活收率的影响,得到了甘薯叶上清液的较优提取纯化方法,即采用热变性,有机物丙酮沉淀及凝胶过滤纯化相结合的方法。热变性最佳时间为15min、温度为60℃,加入丙酮的量为其粗酶液的1.4倍。经凝胶过滤纯化,最终SOD酶活收率为61.5%,蛋白质去除率为97.9%,比活力达到1126.87U/mg,纯化倍数为30.32。     

海洋胶红酵母菌CD-008产超氧化物歧化酶发酵条件优化及酶分离纯化

在单因素试验基础上,结合Plackett-Burman、Box-Behnken设计及响应面分析法进行回归分析以确定海洋胶红酵母菌Rhodotorula sp. CD-008产超氧化物歧化酶最佳发酵条件,并通过盐析、超滤离心、Sephadex G-100凝胶过滤层析研究了酶的分离纯化条件。结果表明,pH、转速、温度对酶活力有显著影响,最优发酵条件为pH 5.34、转速150 r/min、温度21.40 ℃,优化后发酵液酶活力达到6 430.52 U/g湿菌体,比优化前提高了1.53倍。粗酶液经65%饱和度的硫酸铵盐析、超滤离心、Sephadex G-100凝胶过滤层析后获得的SOD比酶活达到419.90 U/mg,纯化倍数为9.60倍,蛋白回收率为8.2%。SDS-PAGE凝胶电泳显示,纯化后的SOD的分子质量约为37.5 ku。     

猪血中SOD的制备工艺及其应用研究

对猪血中SOD纯化工艺及SOD抗氧化性进行研究。采用两次丙酮沉淀法和热处理工艺提纯SOD。热处理对SOD酶活力的影响表明:在60℃下处理15min、SOD酶活力最大,SOD比活力达到4000单位以上;紫外吸收和SDS—聚丙烯酰胺凝胶电泳法分析表明:所提取物为SOD,纯度较高,可作为一般的工业原料。所提取的SOD对新鲜苹果块和冷榨芝麻油具有很好的抗氧化效果。     

黄棒菜超氧化物歧化酶(SOD)分离纯化的技术

以植物新品种黄棒菜为原料,研究料液比,浸提温度及pH,热变性温度及时间、丙酮加入量等因素对黄棒菜超氧化物歧化酶(SOD)提取效果的影响,利用正交试验与单因素试验优化提取工艺。结果表明,提取SOD的最佳条件为:料液比1︰3(g/mL),浸提温度0℃,pH 7.0,50℃热变性20 min,1.5倍酶液体积的丙酮,此时SOD纯化倍数可达3.17。经层析纯化及真空冷冻干燥,获得SOD成品。最佳条件下处理新鲜黄棒菜叶茎、叶片组织,测得SOD最终比活力分别为7662.23 U/mg,4897.39 U/mg,纯化倍数达17.55、23.08,叶茎更适于提取SOD。经电泳检测,黄棒菜SOD相对分子质量约80 kDa,据文献鉴定为Mn-SOD。试验结果为黄棒菜SOD的分离纯化及资源开发提供技术参考。     

大蒜SOD最佳提取条件确定及其生长过程中SOD活力变化研究

采用热变性法、磷酸缓冲液提取法、热变性法+磷酸缓冲液提取法、氯仿-乙醇沉淀法、丙酮沉淀法5种方法对大蒜细胞溶质中超氧化物歧化酶(SOD)进行了粗提、分离纯化.实验结果表明热变性法+磷酸缓冲液混合法所得的SOD的粗提物活性较高;丙酮沉淀法是SOD纯化的最好方法;不同的丙酮加入量与搅拌时间会影响SOD的纯化结果,其最佳条件是加入0.6倍体积的丙酮,搅拌15 min.在此优化条件的基础上,研究不同生长阶段大蒜SOD酶活力,大蒜中SOD酶活力随生长过程,总体成上升趋势.在第五周以后趋于稳定,SOD酶活力达到最高1.210.     

大麦虫超氧化物歧化酶分离纯化及性质研究

目的：探讨大麦虫超氧化物歧化酶(SOD)分离纯化条件及其性质,为大麦虫利用提供科学依据。方法：以大麦虫为原料,经盐析沉淀、DEAE-Sepharose FF阴离子交换柱层析和Sephadex G-75凝胶过滤层析等纯化, 变性聚丙烯酰胺凝胶电泳(SDS-PAGE)方法对蛋白质的组分进行分离并确定其分子质量,原子吸收光谱仪鉴定酶的类型。结果：获得了一种酶比活力较高的大麦虫SOD,酶的纯化倍数为68.54倍,分子质量为37.30kD,属于含铜锌超氧化物歧化酶(Cu,Zn-SOD),且在278nm波长处有紫外吸收峰,稳定性较好,最适温度为40℃,最适pH值为6.0,对H2O2、β-巯基乙醇试剂十分敏感,受氯仿-乙醇混合液(3:5,V/V)的影响较小。结论：大麦虫SOD具有较高的酶比活力,稳定性好,具有较高的利用价值。     

仙人掌超氧化物歧化酶提取、部分纯化及其饮料的制备

以米邦塔食用仙人掌为原料,经匀浆、硫酸铵盐溶、盐析、Sephadex G-75凝胶层析等方法提取纯化超氧化物歧化酶(SOD),仙人掌和黄瓜经清洗除杂、切片、热烫护色、榨汁、澄清、调配和杀菌等工艺,制备仙人掌SOD饮料。结果显示,提取粗酶活力为137.60 U/mL,经提取纯化后SOD比活力为413.68 U/mL,纯化倍数和活力回收率分别为9.25和19.13%。仙人掌SOD饮料口感细腻,具有仙人掌,黄瓜独特的清香味;色泽青绿,无肉眼可见沉淀,SOD酶活力为2 U/mL。     

鹅血中SOD的分离工艺及其抗氧化活性研究

对鹅血中SOD的纯化及抗氧化活性进行了研究.采用丙酮沉淀法对鹅血SOD进行初步纯化、Sephadex G-100进一步精制,并利用SDS-PAGE对酶的纯度检测和分子量测定.结果表明Sephadex G-100凝胶过滤层析对鹅血SOD具有较好的纯化作用,纯化后的鹩血SOD比活力从1 144.896U/mg提高到4 226.513U/mg,SDS-PAGE凝胶电泳显示单一条带,表明已达到电泳纯,且其亚基分子量约为16KD.纯化后的SOD对邻苯三酚自氧化抗氧化活性明显.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.