枸杞多糖的纯化及相对分子质量研究

旨在研究枸杞多糖(LBP)的纯化,并测定其相对分子质量。采用色谱法和溶剂法研究了LBP的脱色条件;利用HPLC法分别考查了醇沉、DEAE纤维素色谱柱和SephedexG-75葡聚糖凝胶色谱柱对LBP的纯化效果,并测定了多糖的相对分子质量。结果表明:最佳脱色条件为多糖溶液(0.2%,g/v)∶氯仿∶正丁醇=25∶5∶1(v/v/v)。5次醇沉可有效减少LBP中的小分子杂质;DEAE纤维素色谱柱可将枸杞多糖分为6个组分,其中以0.15mol/L和0.20mol/L的NaCl溶液为洗脱液获得的组分(LBP-4、LBP-5)含量较高;采用Sephedex G-75色谱柱对LBP-4和LBP-5进行纯化,分别得到LBP-4a和LBP-5a,经琼脂糖凝胶电泳及HPLC检验证明其为纯品,M珚n分别为866130D和1412100D。     

桦褐孔菌多糖的分离纯化及体外抗氧化活性研究

目的 分离纯化桦褐孔菌多糖(Inonotus obliquus polysaccharide,IOP),分析其结构并对其抗氧化活性进行评价.方法 以桦褐孔菌为原材料,采用水提醇沉工艺,经大孔树脂吸附法除杂脱色得到IOP;通过DEAE-52纤维素柱对IOP进行分离纯化,得到4个多糖组分:IOP-1、IOP-2、IOP-3...     

大理百合多糖的醇沉分离工艺及脱蛋白方法

筛选出最佳的大理百合多糖的醇沉分离工艺及脱蛋白方法;比较在不同提取液浓缩比和乙醇加量条件下的多糖沉淀率,筛选出最佳的提取液浓缩比和乙醇加量。从蛋白质清除率和多糖损失率两方面对Sevag法和三氯醋酸法进行比较。对大理百合多糖,提取液∶浓缩液=3∶1(体积比),乙醇加量为4倍体积的浓缩液,Sevag法去除蛋白质为最佳醇沉工艺和脱蛋白方法。     

毛竹竹叶多糖分离与纯化技术研究

对毛竹叶采用超声波提取法获得的竹叶多糖粗提取物,采用Sevag法脱蛋白质、乙醇分级沉淀、冷冻干燥后得到粗多糖,进一步用DEAE-52纤维素柱层析、Sephadex葡聚糖凝胶柱层析等方法分离纯化.结果表明:Sevag法脱蛋白3次可脱除97.2%的蛋白质;50%浓度的乙醇沉淀多糖得率最高,为37.6%;DEAE-52纤维素柱层析柱水沈脱的得牢最高,为46.4%;DEAE-52纤维素柱层析柱2次水洗脱获得的竹叶多糖经G-75柱层析和G-100柱层析可得到白色粉末状的中性多糖.选择水和NaCl溶液为洗脱剂的温和条件分离纯化多糖效果较好.     

香薷多糖的提取与纯化研究

利用热水浸提、乙醇醇沉提取水溶性香薷粗多糖,脱蛋白、除色素后所得的精制多糖经DEAE-52 纤维素阴离子交换色谱得两个组分Ⅰ和Ⅱ。主要组分Ⅱ经Sephacryl S-300 葡聚糖凝胶色谱进一步纯化,得单一多糖组分,命名为HMP Ⅱ。经高效凝胶渗透色谱检测其纯度为93.55%。     

麻竹竹叶多糖分离纯化及相对分子质量测定

为了获得更多竹资源的信息,对麻竹竹叶中的多糖进行了分离纯化及相对分子质量测定的研究。麻竹竹叶水提,提取物Sevage法去蛋白,95%醇沉,透析,DEAE-52纤维素柱和Sephadex G-200凝胶柱分离纯化,得到2种多糖,经高效凝胶渗透色谱测定其相对分子质量(Mw)分别为61500u和1780 ku,该实验为麻竹多糖研究打下基础,为竹资源的深度开发提供科学依据。     

虫草多糖醇沉和DEAE-32纤维素柱层析特性研究

分级醇沉、分步醇沉和DEAE-32纤维素柱层析法研究了虫草多糖的分子量和多糖组分分布.分级醇沉实验表明,各醇沉浓度对应的得率都随醇浓度的升高而呈增加趋势,多糖含量变化起伏较大,醇浓度为30%和70%时所得多糖含量较高,虫草胞内和胞外多糖分子量分布都很不均匀;分步醇沉测定了各部分多糖所占的比例.DEAE-32纤维素柱层析实验结果表明:冬虫夏草的胞外多糖和胞内多糖具有分子量相似的中性多糖峰,并且它们的含量较为接近;二者的酸性多糖组分也具有相似的规律.     

普洱茶多糖分离及纯化

研究10种树脂对普洱茶多糖溶液色素脱除的效果,比较sevag法、三氯乙酸法、盐酸等电点法对普洱茶多糖的脱蛋白质效果.脱色、脱蛋白后的茶多糖经冷冻干燥、透析后,再用DEAE-52纤维素柱层析分离纯化.结果表明:D101大孔吸附树脂为普洱茶多糖脱色的最佳树脂,脱色率为72.27%,多糖保留率为46.97%,脱蛋白率为71.38%;三氯乙酸的脱蛋白效果最佳,添加2%(体积分数)质量分数为50%的三氯乙酸可脱除95.2%的蛋白质;选择水和NaCl溶液作为洗脱剂的温和条件,DEAE-52纤维素柱水洗脱的多糖得率最高,为51.23%.     

桑黄菌丝体多糖的分离纯化及抗氧化、抗肿瘤活性分析

采用水提醇沉法制备桑黄菌丝体粗多糖，分别用终浓度为30%、45%和60%的硫酸铵溶液对桑黄菌丝体中粗多糖进行粗分离，并比较所得各多糖组分的抗氧化、抗肿瘤活性。对其中活性强的组分采用离子交换树脂柱色谱纯化，采用高效排阻色谱-折光示差检测器-多角度光散射仪对纯化多糖进行均一性分析和分子量测定。结果显示，45%硫酸铵分离多糖IPS45显示最强的抗肿瘤活性及较好的清除超氧阴离子活性，IPS45经DEAE-52纤维素离子交换柱纯化得到四个级分，经高效排阻色谱分析，其中蒸馏水洗脱级分（IPS45-W）为均一多糖，重均分子量为79.1 kDa；气相色谱分析其单糖组成为甘露糖:葡萄糖:半乳糖:未知单糖，摩尔比为1.57:8.38:1.09:1.00。IPS45-W可抑制HepG2细胞生长，当浓度为50μg/mL时，对HepG2细胞的抑制率为56.74%，高于前期研究的乙醇沉淀分离所得桑黄菌丝体均一多糖同浓度下11%～35%的抑制率。该结果为不同组成的桑黄多糖的分离和应用提供依据。     

印度块菌多糖的纯化及其理化性质研究

以云南产印度块菌为原料,采用水提醇沉法从其子实体中提取粗多糖,经过Sevage法脱蛋白、DEAE-52纤维素柱层析分离,得到3种多糖组分PTI-1、PTI-2、PTI-3,选择PTI-2通过Sephadex G-100柱进一步纯化,得到了均一纯多糖,命名为PTI-2A,并对PTI-2A进行基础理化测定。结果表明:PTI-2A分子量为193388.2u,易溶于水、稀酸、稀碱,不溶于甲醇、丙酮、氯仿、乙醚和二甲基亚砜等有机溶剂,不含蛋白质、核酸、酚类、淀粉和游离单糖。     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the