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以小麦淀粉生产的副产物谷朊粉为原料,通过单因素实验和正交实验研究酶解时间、底物浓度、酶浓度、溶液pH、酶解温度对谷朊粉水解度的影响,探索碱性蛋白酶酶解小麦谷朊粉的最佳工艺条件。分析发现五个因素对谷朊粉水解度的影响由强到弱的次序依次为:溶液pH酶解温度酶浓度底物浓度酶解时间;结果表明:酶解时间3h、底物浓度9%、酶浓度4%、底物pH=8.0、55℃时谷朊粉的水解度最高,此时谷朊粉的水解度为22.96%。在最佳水解条件下通过Tricine SDS-PAGE确定谷朊粉蛋白多肽的分子量分布范围在8.04~50.12ku之间。 相似文献
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以底物浓度([E])、酶用量([E]/[S])、酶解温度(T)、酶解时间(t)和pH值五个因素作为因变量,采用五元二次正交旋转组合设计确定酪蛋白的水解条件,以水解度(DH)作为考察指标,分析了不同酶解条件对水解度的影响.分析结果表明在试验设定条件下,酪蛋白酶解产物的水解度介于9.74%和24.02%之间,在五个试验因素中,酶解温度对酪蛋白酶解产物水解度的影响最大,酶用量次之.降维分析显示底物浓度与反应时间、酶用量与反应时间、酶解温度与时间等之间的交互作用对酶解产物的水解度均有一定影响. 相似文献
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选用Protex-6L蛋白酶对绿豆分离蛋白进行酶法水解生成肽和氨基酸。以水解度为考察指标,对其酶解工艺进行优化。基于单因素实验,考察了酶解参数:pH、酶解温度、底物浓度、加酶量、酶解时间等对酶解的影响,利用designexpert软件设计响应面对酶解条件进行优化分析,并在最优条件下通过SephadexG-75分析水解产物的分子量分布。结果表明:pH8.85、酶解温度57.34℃、底物质量分数7.00%、加酶量6884.36U/g、酶解时间4.19h,此条件下的绿豆分离蛋白的水解度(DH)为36.60%。水解得到的小肽分子量大部分都小于4000u。 相似文献
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以水解度和氮收率为指标,研究酶制剂种类、底物质量浓度、加酶量、酶解时间、pH 值及酶解温度对牛骨酶解工艺的影响,并采用二次正交旋转组合设计进行工艺优化,得到最佳优化工艺条件:确定木瓜蛋白酶作为试验用酶、底物质量浓度1g/100mL、加酶量6000U/g、酶解温度60℃、pH6.5、酶解时间3h。在该条件下制备的酶解产物水解度可达26.27%。考虑到酶解后固形物的产率,选取底物质量浓度为5g/100mL 进行工艺试验,根据回归方程可得水解度的理论值为18.33%。经反复实验证实,在5g/100mL 的底物质量浓度条件下,牛骨酶解产物水解度可达16.5%~20%,氮收率可达84.5%~92%。 相似文献
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木瓜蛋白酶制备草鱼鳞胶原肽的工艺优化及产物特性分析 总被引:1,自引:0,他引:1
以草鱼鱼鳞为对象,研究木瓜蛋白酶酶解条件对鱼鳞蛋白酶解产物水解度和氮收率的影响,以获得较高氮收率及水解度的鱼鳞胶原肽。结果表明,水解温度、起始pH值、底物浓度和加酶量对木瓜蛋白酶水解产物的水解度和氮收率都有显著影响(p<0.05);木瓜蛋白酶在底物浓度为5%、起始pH值为5.0、加酶量为3000 U/g蛋白、水解温度为60℃条件下水解鱼鳞120 min,鱼鳞水解产物的水解度和氮收率都较好,其水解度为12.68%、氮收率为89.42%;且水解产物在酸性、中性及碱性条件下的溶解性均在97%以上,分子量呈连续分布,主要分布在200~ 5000 u之间。 相似文献
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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. 相似文献
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John Gilbert Catherine Simoneau David Cote Achim Boenke 《Food Additives & Contaminants》2000,17(10):889-893
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. 相似文献
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Sophie Guillot Laurence Peytavi Sylvie Bureau Renaud Boulanger Jean-Paul Lepoutre Jean Crouzet Sabine Schorr-Galindo 《Food chemistry》2006
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. 相似文献
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Jesus Simal-Gandara Miguel Sarria-Vidal Arjen Koorevaar Rinus Rijk 《Food Additives & Contaminants》2000,17(8):703-711
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. 相似文献
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Yoko Uematsu Keiko Hirata Kumi Suzuki Kenji Iida Kazuo Saito 《Food Additives & Contaminants》2001,18(2):177-185
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. 相似文献
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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. 相似文献
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M. S. Garcí a-Falc n J. Simal-G ndara S. T. Carril-Gonz lez-Barros 《Food Additives & Contaminants》2000,17(12):957-964
A simple, rapid and inexpensive method has been developed for the determination of benzo[a 相似文献
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H. J. Van Den Top A. Boenke P. A. Burdaspal J. Bustos H. P. Van Egmond T. Legarda A. Mesego A. Mourino W. E. Paulsch C. Salgado 《Food Additives & Contaminants》2001,18(9):810-824
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. 相似文献
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《肉类研究》2014,(2)
<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 相似文献