木瓜蛋白酶与中性蛋白酶的共固定化及其水解芝麻蛋白的研究

以海藻酸钠为载体,戊二醛为交联剂共固定化木瓜蛋白酶和中性蛋白酶,考察共固定化酶工艺的选择．水解芝麻蛋白的优化条件和共固定化酶的稳定性,芝麻蛋白水解物的复合氨基酸组成。结果表明．共固定化木瓜蛋白酶和中性蛋白酶的最佳条件为：海藻酸钠浓度3％,戊二醛浓度2．5％,氯化钙浓度0．2％,酶活力回收率为51．28％。水解芝麻蛋白的最佳条件为：固液比1：25,pH值6．0,温度60℃,时间7h,加酶量5％,氨基氮含量最高为20．65mg／g,共固定化酶重复使用6次．酶活力仍保持50％以上。芝麻蛋白水解物中15种氨基酸齐全。     

固定化胰蛋白酶水解乌鸡肉制备功能肽的研究

以海藻酸钠为载体,戊二醛为交联剂固定化胰蛋白酶,考察胰蛋白酶的固定化工艺,固定化酶水解乌鸡肉的工艺条件及固定化酶的稳定性。结果表明：固定化胰蛋白酶的最佳条件为：海藻酸钠浓度4%、加酶量10%、pH7.5、温度70℃,酶活力回收率为38.84%;水解乌鸡肉的最佳条件为：固液比1:3(m/V)、pH7.5、加酶量10%、温度60℃,氨基氮含量最高为2.18mg/ml,固定化酶重复使用8 次,酶活力仍保持50% 以上。     

反应条件对酪蛋白水解度的影响

通过单因素实验和正交实验研究了用胰蛋白酶水解牛乳酪蛋白的工艺条件。研究结果表明：胰蛋白酶水解酪蛋白的最佳工艺条件是：pH7．5，温度60℃。底物浓度5％，酶添加量62．44U／g，水解时间140mino在此条件下酪蛋白的水解度达到16．8％。     

固定化Neutrase中性蛋白酶的研究

以壳聚糖为载体、戊二醛为交联剂固定化Neutrase中性蛋白酶。通过单因素实验，分析了壳聚糖浓度、戊二醛浓度、交联时间对微球制备的影响及戊二醛加入量对酶固定的影响。由正交实验确定制备固定化酶的最佳工艺参数为：壳聚糖浓度为3％、戊二醛与葡胺糖残基摩尔比为1：2、制备微球交联时间为1h，微球与酶振荡吸附12h，再加入2．5％戊二醛交联，使戊二醛最终浓度达到0．9％，制备得固定化中性蛋白酶活力为112．69U／g。固定化蛋白酶的热稳定性和对酸碱的稳定性均较游离中性蛋白酶有所提高。     

壳聚精固定胰蛋白酶的研究

以自制壳聚糖为载体,戊二醛为交联剂将胰蛋白酶固定化。5％戊二醛在30℃下处理载体8h,加10ml酶液（0．3mg／ml,pH7．0）固定12h以上,活力回收率达67％－75％。固定化酶的表观米氏常数（酪蛋白）k’m=22．22mg／ml,而游离酶k’m=4.17mg／ml;固定化酶最适温度为80℃,比游离酶提高了30℃;固定化最适pH值为7．5,而游离酶为8．0;固定化酶的贮存稳定性很好,二个多月重复使用,酶活力未见明显下降。     

脱乙酰壳聚糖固定碱性蛋白酶的研究

以脱乙酰壳聚糖为载体，戊二醛为交联剂制备固定化碱性蛋白酶。研究了戊二醛的浓度、给酶量、固定化温度、时间、pH对固定碱性蛋白酶的影响。结果表明：碱性蛋白酶最佳固定化条件是戊二醛浓度为0．2％：给酶量11000U／g；pH为10；在温度为50℃交联时间12h。     

壳聚糖/海藻酸钠固定化β-葡萄糖苷酶的研究

以壳聚糖、海藻酸钠为包埋材料,戊二醛为交联剂,固定化β-葡萄糖苷酶,研究了固定化条件与固定化酶的活力回收的关系.通过单因素和正交实验确定了最佳的固定化方法,即:壳聚糖(脱乙酰度=85%)浓度为1.5%、海藻酸钠浓度为2%、戊二醛浓度为1.0%、钙离子浓度为0.7mol/L、pH为5,固定化酶的活力回收达到83.8%.固定化酶的最适温度为60℃,最适pH为5,该固定化酶重复使用5次后,其活力仍能保持70%.由于β-葡萄糖苷酶比较昂贵,采用固定化技术将其固定在载体上反复使用,可以达到简化工艺、降低成本的目的,作用于大豆异黄酮的水解方面具有潜在的应用前景.     

水酶法提取花生水解蛋白的研究

采用水酶法从冷榨花生饼中提取水解蛋白。以溶出的蛋白质浓度为指标,研究了提取花生蛋白的酶解工艺及条件。结果表明,先用碱性蛋白酶水解再用中性蛋白酶水解效果优于单一酶,碱性蛋白酶最适条件为：温度为55℃,pH值为9．0,加酶量为0．8％,水解时间为3h;中性蛋白酶最适条件为：温度为50℃,pH值为6．5,加酶量为0．3％,水解时间为1．5h。此条件下,蛋白提取率可达90．29％。     

水酶法提取花生水解蛋白的研究

采用水酶法从冷榨花生饼中提取水解蛋白。以溶出的蛋白质浓度为指标,研究了提取花生蛋白的酶解工艺及条件。结果表明,先用碱性蛋白酶水解再用中性蛋白酶水解效果优于单一酶,碱性蛋白酶最适条件为：温度为55℃,pH值为9．0,加酶量为0．8％,水解时间为3h;中性蛋白酶最适条件为：温度为50℃,pH值为6．5,加酶量为0．3％,水解时间为1．5h。此条件下,蛋白提取率可达90．29％。     

吸附交联法固定化蔗糖异构酶及其在异麦芽酮糖制备中的应用

以壳聚糖为载体、戊二醛为交联剂,采用吸附交联法对重组短小芽孢杆菌来源的蔗糖异构酶进行固定化。以表观酶活力回收率为指标,对壳聚糖浓度、戊二醛加量、游离酶加量、固定化时间等条件进行了优化;并考察了温度、pH、固定化酶加量、反应时间以及底物浓度等因素对固定化蔗糖异构酶转化生产异麦芽酮糖的影响。结果表明,最佳固定化条件为：壳聚糖质量浓度3 g/dL、戊二醛加量（体积分数）0.75%、酶加量50 U/g、固定化时间16 h,此时固定化酶活力回收率达到70.3%;最佳转化条件为：温度30 ℃、初始pH 4.5、酶用量15 U/g,转化10 h,蔗糖质量浓度600 g/L,异麦芽酮糖最大产物得率达到87.8%。在最佳的转化条件下连续转化16次,产物得率仍保持在87.52%,显示该固定化酶具有良好的操作稳定性及较高的异麦芽酮糖合成能力。     

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