木瓜蛋白酶水解大豆分离蛋白的研究

大豆分离蛋白经过加热预处理，木瓜蛋白酶２ｈ酶解后，水解度比未处理提高到２倍，最佳处理条件为：９０℃，１０ｍｉｎ。水解度的变化和大豆分离蛋白的ＳＨ含量变化有关。通过极差分析木瓜蛋白酶水解大豆分离蛋白正交实验，结果表明最佳水解条件为：ｐＨ＝７．０，Ｅ：Ｓ＝２．０％，温度５５℃，反应时间１２ｈ。通过ＳＤＳ—ＰＡＧＥ电泳分析水解物得出：大豆蛋白的７Ｓ成分和１１Ｓ的酸性亚单位容易被木瓜蛋白酶作用，１１Ｓ的碱性亚单位由于被酸性亚单位包裹较难水解，酶解物的分子量为２．１万以下。     

木瓜蛋白酶水解大豆分离蛋白的研究

大豆分离蛋白经过加热预处理，木瓜蛋白酶２ｈｒ酶解后，水解度比不处理提高１倍，最佳处理条件为：９０℃，１０ｍｉｎ，水解度的变化和大豆分离蛋白的ＳＨ含量变化有关。通过极差分析木瓜蛋白酶水解大豆分离蛋白正交实验，结果表明最佳水解条件为：ＰＨ＝７．０，Ｅ：Ｓ＝２．０％，温度５５℃，反应时间１２ｈｒ。     

木瓜蛋白酶酶解7S大豆球蛋白的研究

采用实验室提取的7S大豆球蛋白为底物,以水解度为试验考察指标,选择底物浓度、温度、时间、pH值、木瓜蛋白酶酶添加量进行试验.结果表明,木瓜蛋白酶酶解7S大豆球蛋白的最佳工艺条件为:底物浓度4.5%,酶解时间3 h,体系pH值7.2,酶解温度50℃,酶用量为6 000 U/g.原7S大豆球蛋白氮溶解指数(NSI)为40.6%,经最佳酶解条件处理后其NSI值为78.5%.     

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.     

紫贻贝酶解条件的研究

本试验主要测定了紫贻贝的基本组分，并利用中性蛋白酶酸性蛋白酶和碱性蛋白酶对紫贻贝酶解，制备蛋白水解液，采用凯氏定氮法和甲醛电位滴定法计算酶解液的水解度，结合酶解液的感官评价和水解度筛选最适合酶和确定酶解的最佳工艺条件。主要结论如下：紫贻贝中基本组分是粗蛋白含量为9．5％，粗脂肪的含量为6．2％，灰分的含量为2．9％，水分的含量为83．2％；中性蛋白酶的最佳酶解条件：时间3h，pH值7，温度50℃，酶的添加量0．3％，此条件下水解度为39．43％；酸性蛋白酶的最佳酶解条件：时间2h，pH值4，温度50℃，酶的添加量0．3％，此条件下水解度为39．43％；碱性蛋白酶的最佳酶解条件：时间3h，pH值8，温度45℃，酶的添加量0．4％，此条件下水解度为46．51％；在最佳酶解条件下，碱性蛋白酶对紫贻贝的酶解效果明显的好于其它两种蛋白酶，但经感官评定，碱性蛋白酶酶解液苦味和氨味较重，不符合海鲜调味品的风味要求，中性蛋白酶和酸性蛋白酶酶解液的苦味和氨味比较轻，适合作为紫贻贝水解的外加酶，综上分析，选择中性蛋白酶和酸性蛋白酶作为紫贻贝水解的外加酶。     

鲢鱼中肌原纤维蛋白酶法水解的研究

通过测定水解度及对水解液进行感官评价,研究了鲢鱼肌原纤维蛋白的酶水解条件与脱苦脱腥味条件。结果表明：胰蛋白酶单酶水解的最佳条件为：酶用量1．5％,pH8．0,温度45℃,水解时间5h;木瓜蛋白酶单酶水解的最佳条件为：酶用量1．0％,pH7．0,温度50℃,水解时间6h。双酶水解的最佳组合为先加木瓜蛋白酶水解3h,后加胰蛋白酶水解2h。在水解液中添加2．0％～2．5％活性炭,于40℃保温0．5h的脱苦脱腥效果较佳。     

鸡肉多肽酶解条件的研究

探索鸡肉多肽酶解的最佳条件。以鸡肉、木瓜蛋白酶和胰蛋白酶为原料,酶解液中多肽浓度和最终多肽得率为指标,采用单因素和正交实验筛选鸡肉多肽酶解的最佳条件。结果：木瓜蛋白酶用量2．50％（[E]／[S],W/W）,底物浓度9％（[S]）,pH7．70,水解温度60℃,水解时N4h,多肽得率为58．22％。结论：木瓜蛋白酶能有效水解鸡肉获得鸡肉多肽,其酶解鸡肉多肽的得率比胰蛋白酶高。     

RSM优化大豆蛋白酶水解条件

用As1．398中性蛋白酶水解大豆分离蛋白,采用四因素三水平中心组合设计优化大豆分离蛋白酶水解条件,应用SAS分析软件对实验数据进行处理。得以最佳酶水解条件为：温度40．2℃,pH7．2,酶与底物浓度比0．87%(W/W)。底物浓度8．86%(W/W),水解时间3 h；在此条件下水解度预测值为11．28%,实际测定水解度值为11．24%。     

酶法水解小麦面筋蛋白研究

分别采用Alcalase、Neutrase、Protamex、Flavorzyme、胃酶、木瓜蛋白酶对小麦面筋蛋白进行水解研究,结果表明,Alcalase能有效水解面筋蛋白,并确定其最佳水解条件:pH 9．0,温度60℃,底物浓度5％,酶浓度E/S为1％,即0．03AU/g蛋白,反应时间4hr左右,在此条件下,水解度可达 20％左右。     

猪骨呈味物质提取的研究（Ⅰ）—酶解猪骨最佳工艺条件

本实验对猪骨酶解前的热处理和超声波预处理等前处理方法及木瓜蛋白酶和胰蛋白酶双酶水解猪骨工艺进行了研究。结果表明：猪骨热处理的最佳条件为温度90℃，时间10min；猪骨超声波预处理最佳反应条件是：总超声时间为10min、超声波功率为400W。猪骨酶解前经热处理后，水解度和氮收率分别提高了30.84%、10.99%；经超声波预处理后，水解度和氮收率分别提高了84.57%、66.45%；因此，超声波预处理要明显比热水预处理好。试验确定最佳的双酶水解工艺条件为底物浓度15%、E/S6000U/g、酶解时间4h、酶解温度50℃、酶解pH值7.5、木瓜蛋白酶量：胰蛋白酶量1：1。在确定的最佳条件下对猪骨进行超声波预处理和双酶水解，水解度为25.99%、氮收率为66.35%。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press