菠萝蛋白酶水解大豆分离蛋白工艺优化研究

以水解度为指标，研究了温度、pH、底物浓度、酶浓度等因素对菠萝蛋白酶水解大豆分离蛋白的影响。影响菠萝蛋白酶水解大豆蛋白的影响因素顺次为酶浓度、温度、底物浓度、pH。最佳参数组合是酶浓度为6％、温度为65℃、底物浓度为5％、pH为8．0。在此条件下，菠萝蛋白酶水解大豆分离蛋白的水解度在半小时内可以达到8．18％。     

木瓜蛋白酶水解大豆豆渣的工艺优化研究

本试验以大豆豆渣作为试验原材料,大豆豆渣水解度作为评价指标,通过单因素和正交试验探究温度、pH、底物浓度、酶浓度对木瓜蛋白酶水解豆渣效果的影响。结果表明:影响木瓜蛋白酶水解大豆豆渣的主次因素为温度底物浓度pH酶浓度。最优工艺条件参数组合为:温度55℃,底物浓度4%,pH7.0,酶浓度35ug/g。在此条件下,豆渣的水解度达到6.27%。     

木瓜蛋白酶水解大豆蛋白的工艺优化研究

以大豆蛋白水解度为指标,通过单因素和正交试验研究了温度、pH、底物浓度和酶浓度四因素对木瓜蛋白酶水解大豆蛋白工艺的影响,并优化了工艺条件。试验结果表明,影响木瓜蛋白酶水解大豆蛋白的主次因素为温度、pH、酶浓度、底物浓度。最佳工艺参数组合为:温度60℃,pH7.5,酶浓度3.5%,底物浓度5%。在此工艺条件下,木瓜蛋白酶水解大豆蛋白40 min,水解度达到6.58%,大豆肽的氨基酸平均数目为15,平均分子量为1875。     

酶法水解血球蛋白工艺及其参数研究

本试验通过测定酶解的水解率,选择水解猪血血球蛋白的最优蛋白酶,并确定酶的最佳水解条件(包括底物浓度、酶添加比例、pH值、温度、反应时间以及沉淀血红素的pH值)。试验结果表明,最佳水解条件为底物浓度10%、酶添加比例8‰、pH7.5、水解温度53℃、水解时间为10h。     

酶水解高温豆粕制备高水解度大豆肽的研究

采用碱性蛋白酶水解高温豆粕制备高水解度大豆肽,通过单因素和响应面实验确定酶解高温豆粕的优化条件。以水解度为指标,考察温度、时间、pH、加酶量、底物浓度等因素对水解度的影响。优化的酶解条件为:温度50℃、时间5h、pH8.60、加酶量17700U/g底物、底物浓度10.25%,该条件下得到大豆肽的水解度为37.20%。     

板栗淀粉酶水解工艺条件研究

为探索板栗淀粉酶水解特性及工艺条件,采用中温α-淀粉酶对板栗淀粉进行水解,并在水解温度、pH、底物浓度及酶用量等单因素试验的基础上进行二次回归正交旋转试验,确定板栗淀粉酶解工艺条件.结果表明:对α-淀粉酶水解板栗淀粉影响程度大小依次为pH＞水解温度＞酶用量＞底物浓度;α-淀粉酶水解板栗淀粉的适宜工艺条件为:水解温度70.2 ℃,pH 5.83,底物浓度73.10 g/L,酶用量122.45 U/g,水解时间为75 min.在此工艺条件下板栗淀粉酶水解度为27.476% .     

枯草芽孢杆菌蛋白酶水解大豆蛋白的研究

本研究选用枯草芽孢杆菌蛋白酶对大豆蛋白进行水解,分别研究了酶浓度、温度、pH和底物浓度等对酶解效果的影响,得出高水解度低聚肽酶解的最佳工艺条件为:酶浓度8000u/g、温度55℃、pH7.0、底物浓度2%、水解时间4h。     

生物酶法酶解猪血红蛋白 (Hb)的研究

以猪血红蛋白的水解率、氮溶解指数、总氮收率及血红素含量为指标,选择温度、pH、酶底物浓度比([E]/[S])、底物浓度([S])为试验因素,选用L9(3+)正交表对其水解条件进行探讨.结果表明其最佳水解条件为最初pH7.5,温度为55℃,酶底物浓度比(E/S)8000U/g,底物浓度6%,水解时间8h.     

序贯设计优化大豆多肽制备工艺

以大豆分离蛋白为原料,在pH渐变条件下用碱性蛋白酶水解制备大豆多肽。采用序贯设计的方法考察了底物浓度、起始pH、温度、酶浓度、酶解时间对大豆蛋白水解的影响,并由此确定了最佳的酶解工艺条件:底物浓度4.92%、酶与底物蛋白比为2 758 kat/g蛋白、温度55℃、起始pH 11.0、水解时间7 h。在优化的条件下大豆蛋白的水解度可达到39.10 mg/100 g,多肽得率为63.21%。     

Protamex复合蛋白酶水解大豆分离蛋白的研究

为优化大豆分离蛋白酶水解条件，本试验采用二次回归正交旋转组合设计方法对Protamex复合蛋白酶水解大豆分离蛋白的条件进行研究。建立了水解度(DH)与pH值、反应温度、反应时间、底物浓度、酶与底物浓度比之间的数学模型；并获得最佳水解工艺条件：pH值6．5，温度40℃，水解时间10h，底物浓度14％，酶与底物浓度比4．5％；主成分分析表明，pH对DH的贡献率最大。     

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