蛋白酶法提取乌骨鸡黑色素的研究

选用江西泰和乌骨鸡为研究对象，采用酶法水解蛋白质分离乌鸡黑色素。结果表明：酸性蛋白酶为最优水解酶，加酶量3．8％、肉水比1：2，其最佳酶解条件pH2．8、酶解温度34．8℃、酶解时间20h。与盐酸法相比，酶法黑色素的得率高于盐酸法。     

双酶分步水解酱香型白酒丢糟中粗蛋白的工艺研究

以水解度(DH)和蛋白质得率为评价指标,研究了酸性蛋白酶、中性蛋白酶、碱性蛋白酶和木瓜蛋白酶分别对酱香型白酒丢糟中粗蛋白的水解效果。结果表明:碱性蛋白酶和木瓜蛋白酶的水解效果最好。在碱性蛋白酶和木瓜蛋白酶的水解条件单因素试验的基础上进行正交优化试验,得到两种酶的最佳水解条件。为进一步提高丢糟中粗蛋白的水解度和蛋白质得率,采用碱性蛋白酶和木瓜蛋白酶对酱香型白酒丢糟中粗蛋白进行分步酶法水解。结果表明,酱香型白酒丢糟中粗蛋白的最佳水解工艺条件为先用碱性蛋白酶酶解(酶解温度为55℃,料液质量比为1︰10,加酶量[E]/[S]为2.0%,p H 8.0,酶解时间为3 h),灭酶后,再用木瓜蛋白酶酶解(其他条件不变,加酶量[E]/[S]为0.2%,酶解时间为1 h)。在此条件下得到水解度和蛋白质得率,分别为32.91%,49.16%。     

辣椒粕分离蛋白酶解工艺条件的优化

从辣椒粕中提取粗蛋白,建立蛋白酶水解辣椒粕分离蛋白制备呈味肽的最佳条件。以水解度和肽得率为指标,对胰蛋白酶、木瓜蛋白酶、碱性蛋白酶、复合蛋白酶4种酶水解辣椒粕分离蛋白的效果进行比较研究。结果表明:复合蛋白酶的水解效果最佳。通过单因素试验选取复合蛋白酶作用的固液比、酶用量、酶解时间、酶解pH值及酶解温度作为试验因素,初步确立复合蛋白酶的水解条件。并通过正交试验优化最终确定复合蛋白酶水解辣椒粕分离蛋白的最佳工艺条件为固液比110(mV),酶用量2.0%,酶解时间4h,酶解pH值6.5,酶解温度50℃。通过实验验证,在该条件下,复合蛋白酶对辣椒粕分离蛋白具有较好的水解效果,其水解度为19.60%,肽得率为6.30%。     

金乌贼墨黑色素酶解工艺优化

为了获得高品质的金乌贼(Sepia esculenta)墨黑色素,使用酶解法去杂,研究金乌贼墨黑色素酶解的最佳工艺。以水解度为指标,从中性蛋白酶、酸性蛋白酶、碱性蛋白酶、风味蛋白酶、木瓜蛋白酶中筛选得到最佳酶,在单因素实验的基础上,通过响应面分析法研究酶解温度、加酶量和酶解时间对金乌贼墨黑色素水解程度的影响,优化酶解工艺条件,并通过红外光谱(Infrared spectra,IR)、紫外-可见分光光度法和扫描电子显微镜(Scanning electron microscope,SEM)对黑色素性质结构进行表征。结果表明,以风味蛋白酶酶解金乌贼墨黑色素,最佳酶解条件为料液比2%,酶解温度51℃,pH7.0,加酶量3750 U/g,酶解时间6.5 h,此时水解度为19.53%±0.05%,黑色素得率为17.02%。红外光谱显示提取的黑色素具有典型的吲哚环结构;紫外-可见分光光度法测得黑色素吸光值明显增大;扫描电镜观察发现黑色素平均粒径明显减小,颗粒大小更均匀。由此可知风味蛋白酶酶解法能有效提高乌贼墨黑色素的纯度,本研究可为金乌贼墨黑色素的提取和高值化应用提供技术指导和理论依据。     

文蛤肉复合酶分步酶解工艺的研究

本实验探讨了中性蛋白酶和胰蛋白酶的复合酶与风味蛋白酶分步酶解文蛤肉的技术。 通过q检验法确定中性蛋白酶和胰蛋白酶最佳的复合比例,再通过正交试验探讨复合酶与风味蛋白酶二段酶解的最佳工艺参数,并以水解度、水解得率及风味评分值为指标对分步酶解工艺的最佳条件进行比较验证。结果表明,胰蛋白酶与中性蛋白酶的最佳复合比例为3:1,风味蛋白酶二段酶解的最优工艺参数为水解温度55℃、水解时间5.0h、加酶量1000 U/g(原料)、pH值(5.00±0.05),所得文蛤肉水解液中水解度、水解得率及风味评分值分别为55.97%、87.14%及230.98。     

分步酶解法制备黄浆水活性肽

黄浆水是传统豆制品点脑成型过程压榨出的废弃物,富含低聚糖、蛋白质等营养成分。该研究通过比较酶种类及用量、酶解温度、酶解时间对黄浆水蛋白质水解度的影响,采用正交试验优化获得黄浆水短肽最佳分步酶解工艺：（1）酸性蛋白酶加酶量2 000 U/g,pH 4.0,温度55 ℃,水解2 h;（2）中性蛋白酶8 000 U/g,pH 6.0,温度50 ℃,水解6 h。在此条件下进行验证,水解度可达25.95%,血管紧张素转化酶体外抑制活性达92.0%。采用酸性蛋白酶和中性蛋白酶分步酶解黄浆水制备短肽,制备条件温和,水解度高,可为豆制品加工废弃物的高值化利用奠定基础。     

黑羽乌骨鸡毛中黑色素提取工艺

以黑羽乌骨鸡毛为原料,采用盐酸水解法从乌骨鸡毛中提取黑色素并对黑色素的含量进行测定。通过单因素实验考察了提取时间、盐酸浓度、料液比对乌骨鸡毛中黑色素得率的影响,在单因素实验基础上通过响应面实验分析法得到二次多项式回归方程的预测模型。结果表明:乌骨鸡毛中黑色素提取的最佳工艺条件为,HCl浓度27%,提取时间6h,料液比(g∶mL)1∶2,在此条件下黑色素得率达4.72%。黑色素样品经过氧化氢法氧化处理,采用高效液相色谱法测出黑色素含量为76.20%。     

乌骨鸡黑色素的酶法提取及其抗氧化作用的初步研究

以江西泰和乌骨鸡为研究对象,研究酶法水解乌鸡蛋白质分离黑色素的最佳工艺条件,并对黑色素清除DPPH自由基,以及黑色素延缓油脂酸败的能力进行了研究。结果表明:(1)酸性蛋白酶为最优水解酶,其加酶量3.8%、固液比1∶2;其最佳酶解条件pH2.8、酶解温度34.8℃、酶解时间20 h。(2)乌鸡黑色素能抑制DPPH.自由基,抑制率随黑色素浓度增加而提高。(3)黑色素能延缓油脂酸败,在70℃时添加浓度为0.1 mg/mL的黑色素于油脂中,60 h时酸价为0.3028 mg KOH/g,而对照(不加黑色素)的酸价在第32 h即升到0.3130 mg KOH/g。     

乌骨鸡深加工酶解处理条件的探索研究

对乌骨鸡进行深加工,提高蛋白质的综合利用率,增加氨基酸尤其是游离氨基酸的含量,便于人体对其吸收利用。本论文阐述了研究国际上领先的酶制剂Flavourzyme风味蛋白酶水解乌骨鸡动物蛋白质的水解条件。特点是在原来采用传统炮制工艺提取乌骨鸡有效成分的基础上采用了现代生物工程-酶解技术,对乌骨鸡进行深度水解处理,比一般的和传统的酶解有更高的产率和更好的风味及口感。确定了正交分解试验方法,分别测定水解率,进行方案组合,确定最佳处理条件。结果表明,乌骨鸡肉经90℃,10min的加热预处理可促进酶解。酶解最佳条件为:pH=7.0,温度45℃,酶与底物浓度之比为0.5LAPU/g,底物浓度11%,时间3h。     

乌骨鸡黑色素三步法提取及结构性状研究

采用"脱脂-酶解-酸解"三步法提取乌骨鸡黑色素,研究酸液脱除蛋白,分离乌骨鸡黑色素的工艺条件,通过透射电镜对乌骨鸡黑色素纯化效果进行观察,并用元素分析仪对其结构进行分析。结果表明:最佳脱脂工艺为乙醇回流脱脂4次,每次1h,料液比1∶2,此工艺条件下乌骨鸡油脂得率7.5%。脱脂后用蛋白酶C进行酶解,酸化的最优工艺盐酸浓度为2mol/L,回流时间为3h,固液比为1∶10,回流次数为4次,此条件下杂质脱除率最高,且条件温和,通过透射电镜可见三步法纯化的黑色素颗粒形态完整,边缘清晰平滑,无破坏痕迹,可用于降解和结构研究。根据元素分析仪推测乌骨鸡黑色素是一类有别于真黑色素及脱黑色素的特殊黑色素。     

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