酶解高水解度大豆蛋白肽的研究

通过对中性蛋白酶、木瓜蛋白酶、Alcalase碱性蛋白酶3种酶对大豆分离蛋白水解程度的研究，优化试验方案，探索制备高水解度大豆蛋白水解液的条件组合，并对3种酶进行了比较，以找出适合于大豆蛋白水解的蛋白酶。     

酶解高水解度大豆蛋白肽的研究

通过对中性蛋白酶、木瓜蛋白酶、Alcalase碱性蛋白酶3种酶对大豆分离蛋白水解程度的研究,优化试验方案,探索制备高水解度大豆蛋白水解液的条件组合,并对3种酶进行了比较,以找出适合于大豆蛋白水解的蛋白酶。     

乳清蛋白的酶法改性研究

采用碱性蛋白酶、风味蛋白酶、木瓜蛋白酶、中性蛋白酶、复合蛋白酶、胰蛋白酶、胃蛋白酶在各自的最适条件下对乳清蛋白粉进行水解,通过HPLC方法测定酶解产物中α-乳白蛋白（α—La）和β-乳球蛋白（β—Lg）的含量。结果表明,碱性蛋白酶对其水解最快,其次为木瓜蛋白酶,而在胃蛋白酶和胰蛋白酶作用下则不易酶解,而且发现α-La比β—Lg更容易水解。     

不同酶解方式对豆粕大豆蛋白组分和抗原活性的影响

以低温脱脂豆粕提取的大豆蛋白为原料,分别采用碱性蛋白酶、木瓜蛋白酶和双酶联合方法水解大豆蛋白,分别采用十二烷基硫酸钠-聚丙烯酰氨凝胶电泳和竞争法酶联免疫吸附试验分析水解过程中蛋白质组分和抗原活性的变化.结果表明:碱性蛋白酶水解30 min即可基本去除大豆蛋白7S组分中的α-亚基和α'-亚基,木瓜蛋白酶水解10 min即...     

碱性蛋白酶和木瓜蛋白酶对热变性大豆分离蛋白的酶解研究

采用碱性蛋白酶和木瓜蛋白酶对热变性大豆分离蛋白进行酶解,研究两种蛋白酶酶解温度对大豆分离蛋白酶解效果的影响。结果表明:碱性蛋白酶在60℃时比在70℃时对大豆分离蛋白的酶解更彻底,得到的相对分子质量小的肽段更多,大豆分离蛋白的水解度较高(14.73%);酶解温度对木瓜蛋白酶酶解大豆分离蛋白的效果影响不明显;与木瓜蛋白酶相比,碱性蛋白酶酶解大豆分离蛋白可以得到更多的小分子肽段。     

酶法钝化大豆胰蛋白酶抑制剂的研究

采用中性蛋白酶、碱性蛋白酶、酸性蛋白酶和木瓜蛋白酶，在其最适pH值和最适温度下水解低温脱脂豆粕1h，分别检测水解前后胰蛋白酶抑制剂活性的变化。结果表明，4种酶都可在不同程度上降解大豆胰蛋白酶抑制剂，但降解程度差异较大，碱性蛋白酶降解作用显著优于其它酶。按照四种酶水解胰蛋白酶抑制剂相对活力的大小排序为：碱性蛋白酶＞酸性蛋白酶＞中性蛋白酶＞木瓜蛋白酶。     

大豆球蛋白酶解物清除DPPH自由基活性的研究

以7S和11S大豆球蛋白为原料,用Alcalase碱性蛋白酶、Neutrase中性蛋白酶、胰蛋白酶、木瓜蛋白酶、菠萝蛋白酶制备大豆球蛋白酶解产物,分别测定其DPPH(1,1-二苯基苦酰基苯肼)自由基清除活力和水解度,从5种蛋白酶中筛选出碱性内切蛋白酶酶解物的清除活力最高,且相同水解时间的水解度最大.选择碱性蛋白酶为最佳水解酶,利用正交试验优化了其最佳水解条件,碱性内切蛋白酶水解7S和11S大豆球蛋白的最佳条件为:温度55℃,pH 8.0,酶用量5%,底物浓度4%.结果表明:在最佳水解条件下,7S大豆球蛋白酶解物的DPPH自由基清除活力比11S大豆球蛋白酶解物的高.     

酶法大豆蛋白水解程度控制研究

通过研究不同蛋白酶对大豆分离蛋白的水解程度和最佳水解条件以及对水解后大豆蛋白功能性的影响研究,确立了酶水解法制备不同功能性大豆蛋白的工艺路线和工艺条件,即分散性较好、具有凝胶性的大豆分离蛋白采用木瓜蛋白酶或中性蛋白酶水解,水解度控制在5％～6％;乳用(高分散性)大豆分离蛋白采用NoVo复合蛋白酶水解,水解度控制在14％～15％,并可强化钙作为特殊产品需要。     

制备大豆降血压肽最佳用酶的筛选

以大豆分离蛋白为原料,选用胃蛋白酶、胰蛋白酶、碱性蛋白酶、中性蛋白酶、风味蛋白酶、木瓜蛋白酶、菠萝蛋白酶和双酶复合来水解制备大豆降血压肽,以血管紧张素转化酶(ACE)抑制率为主要指标,筛选出制备大豆降血压肽最佳的酶。结果表明,大豆降血压肽ACE抑制率的大小与酶的种类及配比有关,筛选出碱性蛋白酶为最佳用酶,在6h左右达到最大抑制率68.54%。     

酶法钝化大豆胰蛋白酶抑制剂研究

采用中性蛋白酶、碱性蛋白酶、酸性蛋白酶和木瓜蛋白酶,在其最适ｐＨ值和最适温度下水解低温脱脂豆粕１小时,分别检测水解前后胰蛋白酶抑制剂活性的变化。结果表明,四种酶都可在不同程度上降解大豆胰蛋白酶抑制剂,但降解程度差异较大,碱性蛋白酶降解作用显著优于其它酶。按照四种酶水解胰蛋白酶抑制剂相对活力的大小排序为:碱性蛋白酶＞酸性蛋白酶＞中性蛋白酶＞木瓜蛋白酶。     

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