从发酵液中提取高纯度L-脯氨酸的工艺研究

采用膜过滤技术对L-脯氨酸发酵液进行预处理,使用孔径为1 μm的陶瓷膜在30℃～60C,膜滤压力差选择2.5bar～7.5 bar的条件下得到较好的过滤除菌效果.通过树脂吸附试验,考察了pH和不同树脂对L-脯氨酸吸附情况的影响,确定了使用732#阳离子交换树脂进行吸附,上柱发酵液pH3.5,上柱流速0.6 BV/h,洗脱液为0.8 mol/L NH4C1,洗脱体积流量为0.4 BV/h,高流液经脱色、浓缩结晶后得到L-脯氨酸成品,总提取率为65％.     

从发酵液中提取高纯度L-脯氨酸的工艺研究

采用膜过滤技术对L-脯氨酸发酵液进行预处理,使用孔径为1μm的陶瓷膜在30℃-60℃．膜滤压力差选择2．5bar-7．5bar的条件下得到较好的过滤除菌效果。通过树脂吸附试验,考察了pH和不同树脂对L-脯氨酸吸附情况的影响,确定了使用732#阳离子交换树脂进行吸附,上柱发酵液pH3．5,上柱流速0．6BV／h,洗脱液为0．8mol／L NH4Cl,洗脱体积流量为0．4BV／h,高流液经脱色、浓缩结晶后得到L-脯氨酸成品,总提取率为65％。     

槲寄生中黄酮类化合物纯化工艺研究

研究大孔吸附树脂法分离纯化槲寄生总黄酮的工艺条件.选择4种大孔吸附树脂(AS-8,NKA-9,NKA-Ⅱ,D101),以吸附率和解吸率为评价指标,筛选出较优的槲寄生总黄酮吸附剂,并对其动态吸附性能进行考察.结果:AB-8分离效果最好,其最佳工艺为上柱原液pH值4左右,上柱速度2 BV/h,以40%乙醇为洗脱液控制洗脱液流速1 BV/h,洗脱液用量为4 BV,经AB-8纯化后,槲寄生产品中黄酮的纯度由12.16%提高到69.63%,提高了5.73倍,回收率为81.36%.     

大孔树脂串联吸附原花青素和茶皂素的工艺研究

采用大孔树脂分级串联的方法吸附茶壳提取液中的原花青素和茶皂素,经试验得到最佳工艺条件:将茶壳提取液经过DM–130大孔树脂进行1级吸附,调节上柱液中茶皂素的浓度为1.5 mg/m L,pH为6,吸附流速为1.5 BV/h,吸附完毕后采用50%乙醇进行洗脱,洗脱液浓缩干燥后得到纯度为85.6%的茶皂素产品。收集流出液并经S–8树脂进行2级吸附,调节上柱液中原花青素的浓度为1 mg/m L,pH为4,吸附流速为2 BV/h,吸附完毕后采用30%乙醇进行洗脱,洗脱液浓缩干燥后得到纯度为73.7%的原花青素产品。     

D001阳离子交换树脂分离红曲霉发酵液中γ-氨基丁酸的研究

研究了红曲霉发酵液中的γ-氨基丁酸(GABA)分离纯化工艺。对3种脱色剂进行筛选,D101树脂对红曲发酵液具有最高的脱色率和GABA得率。分别以静态和动态吸附-解析方法考察D001离子交换树脂对GABA的最优分离条件,结果表明:脱色发酵液pH下上样,上样流速为1 BV/h,采用水和2 mol/L氨水两步洗脱,洗脱液浓缩后结晶为透明针状,GABA的总得率为45.4%。     

AB-8型大孔吸附树脂分离纯化鼠曲草总黄酮工艺

采用AB-8型大孔树脂对从鼠曲草中提取的总黄酮产物进行分离纯化研究。考察各种因素对树脂吸附和洗脱效果的影响。通过实验得到最佳吸附工艺条件为上样液流速2BV/h、上样液pH4.5、上样液质量浓度1.7mg/mL;最佳洗脱工艺条件为洗脱液体积分数为60%乙醇、洗脱液流速1BV/h和洗脱液用量1.8BV。分离纯化后的总黄酮产品纯度可达35.42%。     

AB-8树脂纯化柿叶总黄酮的工艺研究

目的:筛选出分离纯化柿叶总黄酮的最佳树脂,并对影响分离纯化的因素进行研究,得到优化的纯化条件。方法:选用AB-8、ADS-17和D3520三种型号大孔吸附树脂,采用动态吸附-解吸方法,利用分光光度法测定黄酮含量,研究了不同的大孔吸附树脂及其不同的工艺条件对柿叶黄酮分离纯化的影响。结果:实验表明AB-8树脂的分离效果最好,其最佳工艺为:上柱液pH6,上柱液流速2BV/h,样液浓度为3mg/mL,70%乙醇为洗脱液,洗脱液流速控制在2BV/h,洗脱液用量为3BV。在此条件纯化后,柿叶黄酮提取物中黄酮含量由9%提高到34%。结论:AB-8大孔树脂可以较好地分离纯化柿叶黄酮。     

大孔吸附树脂分离富集水皂角多酚

运用静态吸附与解吸实验对大孔树脂进行筛选,然后,通过单因素实验、正交实验以及方差分析确定了水皂角多酚分离富集的最佳操作条件。结果表明,S-8大孔树脂表现出最好的吸附性能与良好的解吸效果。确定的最佳吸附条件为A3B2C3,即上柱速度为2.5BV/h,料液浓度为4mg/ml,料液pH值为6.5,最佳洗脱条件为A2B3C2D1,即乙醇浓度为75%,洗脱流速为2BV/h,洗脱液pH值为8,洗脱体积为3.5BV。     

D-101树脂纯化胭脂虫红色素的工艺研究

为了提高胭脂虫红色素的纯度,研究了D-101树脂纯化胭脂虫红色素的工艺。比较了不同pH值预处理胭脂虫红色素提取液的吸附效果,研究了树脂动态吸附和洗脱动力学曲线,并对树脂吸附条件和洗脱条件进行了研究。优化得到D-101树脂纯化胭脂虫红色素的最佳工艺条件为:提取液采用pH为3进行预处理,上柱液体积为2BV,上柱流速为3BV/h,体积分数为75%的乙醇洗脱,洗脱液体积为3.5BV,洗脱速率为2BV/h,在此条件下,吸附量为42.15mg/mL树脂,洗脱率高达98.24%,胭脂虫产品纯度可达58.47%,能够满足一般食品工业的对胭脂虫红色素的纯度要求。采用D-101大孔吸附树脂分离提纯胭脂虫红色素具有吸附量较大、洗脱率高、产品纯度较高、适合工业化大规模生产等优点,具有广阔的工业应用前景。     

大孔吸附树脂分离夏枯草果穗总黄酮的研究

通过比较D-101、AB-8、X-5、DA-201、HZ-806和HZ-801 6种不同性质大孔吸附树脂对夏枯草果穗总黄酮的静态吸附和解吸附性能,筛选出适合夏枯草果穗总黄酮分离纯化的树脂,并对其进行动态吸附特性研究。静态吸附实验结果表明,弱极性AB-8大孔吸附树脂对夏枯草果穗总黄酮具有较好的吸附和解吸附效果。动态吸附实验得其最佳动态吸附分离工艺参数为:上柱原液pH为3.0~3.5,上柱液体积3BV/次,上柱速度6BV/h,上样液浓度为1.8mg/mL。洗脱液乙醇浓度70%,洗脱液流速6BV/h,洗脱液用量6BV/次。在此条件下,树脂使用1次时,总黄酮吸附率和回收率分别达92.36%和89.09%,总黄酮的纯度由41.58%提高到70.68%;树脂重复使用4次时,总黄酮的收率和纯度仍达80%和60%以上。     

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