大孔吸附树脂对酪蛋白酶解液的脱盐作用研究

本文研究了DA201-C、NKA-II、AB-8、XAD1180、XAD16和HZ-816六种大孔吸附树脂在酪蛋白酶解液吸附和解吸附过程中的脱盐作用。在了解树脂物理参数的基础上,通过静态吸附实验,筛选出脱盐效果最佳的树脂和洗脱液,然后进行动态吸附实验研究。结果表明:DA201C对酪蛋白酶解液的脱盐是最佳的,而且采用70%乙醇溶液为洗脱剂时洗脱率和脱盐率均较高。     

大孔吸附树脂对酪蛋白酶解物的吸附特性研究

比较了6种大孔吸附树脂对酪蛋白酶解物的吸附特性.结果表明,DA201-C大孔吸附树脂较适合酪蛋白酶解物的分离,其对酪蛋白酶解物的动态吸附条件为:样品浓度:10mg/mL;洗脱荆:50%乙醇溶液;洗脱剂流速:1.5BV/h.     

大孔树脂对酶解大豆肽脱盐效果影响及其最佳条件研究

本文旨在研究不同种类大孔树脂对酶解大豆肽吸附和解吸过程中脱盐效果的影响及其最佳条件。以酶解大豆肽为研究对象,首先以DA201-C、AB-8、D3520、D4006和NAX-Ⅱ5种不同的大孔吸附树脂进行酶解大豆肽的脱盐效果研究,得出DA201-C树脂对酶解液的脱盐效果最好;并对DA201-C树脂进行静态吸附解析工艺的优化并测定其动态吸附解吸实验,得出最佳条件为:pH4.5,酶解液浓度为60mg/mL,75%乙醇洗脱,脱盐率达到93.23%,肽回收率为88.5%。     

大孔吸附树脂对草鱼蛋白水解液脱盐的作用

为了脱除草鱼蛋白水解液中的盐,本研究筛选了4 种型号大孔吸附树脂DA201-C、DA201-M、SQT-67和D002,对水解液中草鱼多肽的吸附能力进行测定,并进行静态吸附和解吸实验。结果表明：大孔吸附树脂DA201-C对草鱼多肽的吸附效果较好,其吸附量随草鱼多肽质量浓度的增加而增加;体积分数75%的乙醇对大孔吸附树脂DA201-C的洗脱效果最佳;DA201-C大孔吸附树脂对水解液脱盐的最佳条件为上样流速0.5 BV/h,上样质量浓度为30 mg/mL,水清洗速率为2 BV/h,洗脱采用体积分数75%的乙醇以2 BV/h的流速洗脱,在此条件下大孔吸附树脂DA201-C对水解液的脱盐率达97.17%。     

DA201-C大孔吸附树脂纯化大豆多肽条件优化

采用大孔吸附树脂纯化豆粕蛋白酶解液中的大豆多肽,经静态吸附和解吸试验表明:DA201-C大孔吸附树脂对大豆多肽的吸附性能及脱盐效果优于其他8种树脂,其最佳工艺条件:上样流速1.08mL/min、上样浓度13.6mg/mL、上样体积240mL、水洗脱体积400mL、75%乙醇洗脱体积500mL,在此条件下,大豆多肽含量提高了70.35%、糖含量降低了70.8%、盐含量降低了93.93%、大豆多肽回收率为62.16%。     

大孔吸附树脂对蛋清蛋白水解物的吸附特性研究

为纯化蛋清蛋白质水解物以得到质量良好的产品，采用大孔吸附树脂对蛋清蛋白质水解液进行脱盐处理。对9种不同树脂进行了筛选实验，通过测定9种树脂的吸附率与解吸率衡量它们的性能，发现DA201-C型树脂的吸附率为80．85％，解吸率在70％酒精作为洗脱剂时为79．27％，两项指标皆优于其它树脂，从而筛选出最佳树脂为DA201-C型。为了阐明吸附行为的物化本质，进一步对吸附的静态吸附动力学与热力学性质进行了研究，结果表明：树脂对EWPH的吸附属于快速平衡型，且是吸热的物理吸附过程。     

DA201-C大孔吸附树脂对腐乳多肽脱盐作用的研究

为去除腐乳中的盐分,利于其中活性肽的分离纯化,以腐乳多肽的回收率为指标,采用DA201-C大孔吸附树脂对超滤的水溶性低聚肽的脱盐工艺进行了研究。结果表明:DA201-C大孔吸附树脂对腐乳多肽较佳的脱盐工艺条件为上样浓度45 mg/mL、洗脱流速120 mL/h、解吸剂为70%乙醇。腐乳多肽经DA201-C大孔吸附树脂处理后脱盐率达到98.19%,肽回收率大于90%,抗氧化活性得到提高。利用DA201-C大孔吸附树脂是进行腐乳多肽脱盐处理的一种简便有效方法。     

利用大孔吸附树脂DA201-C Ⅱ对燕麦蛋白水解液脱盐的研究

采用大孔吸附树脂DA201-C Ⅱ对燕麦蛋白水解液进行脱盐处理是行之有效的方法。静态吸附和解吸实验表明,大孔吸附树脂DA201-C Ⅱ对燕麦肽的吸附性能优于其他七种树脂,其最佳工艺条件为：pH4.0、多肽浓度39mg/ml 的酶解液以1BV/h 的流速上样、1BV/h 的流速水洗、1.5ml/min 的75% 乙醇解吸。在此条件下,大孔吸附树脂DA201-C Ⅱ对水解液的脱盐率为93.4%,燕麦肽的回收率可达72.3%。     

大孔树脂对罗非鱼皮胶原蛋白抗氧化肽脱盐作用的研究

为了探索罗非鱼皮胶原蛋白抗氧化肽的最佳脱盐工艺,本文采用DA201-C大孔吸附树脂对抗氧化肽进行脱盐试验。结果表明:DA201-C大孔吸附树脂对抗氧化肽的静态吸附率和吸附量分别为82.56%和54 mg/g;动态吸附和解吸最佳的上样浓度为60mg/mL,最佳上样流速为1 mL/min,解吸剂为75%乙醇。抗氧化肽经过DA201-C大孔吸附树脂处理后脱盐率为97.13%,回收率为81.16%,质量浓度为0.245 mg/mL时对ABTS自由基的清除率提高至39.58%。采用DA201-C大孔吸附树脂对罗非鱼皮胶原蛋白抗氧化肽进行脱盐处理是一种简便有效的方法。     

大孔吸附树脂对乳铁蛋白抗菌肽脱盐作用的研究

研究了乳铁蛋白抗菌肽在DA201-C大孔吸附树脂吸附和解吸过程中的脱盐作用.通过静态吸附实验,得到了吸附的动力学曲线及方程、吸附等温线和最佳洗脱液浓度.对于10mg/mL的乳铁蛋白抗菌肽,吸附速率方程为Y=0.5035X-0.3971(R2=0.9045);其浓度为30mg/mL时,吸附速率方程为Y=0.4887X 1.0815(R2=0.9412).动态吸附实验结果表明:在采用85%乙醇为洗脱剂时,DA201-C对乳铁蛋白抗菌肽的脱盐率超过97%,回收率达到92%.     

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.     

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.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.