茶多酚对米曲霉α-淀粉酶的回收及其特性的影响

研究绿茶中多酚类对米曲霉来源的α－淀粉酶特性的影响。从绿茶中提取茶多酚（TP），对米曲霉α－淀粉酶进行络合，沉淀及回收；以Bernfeild法测定α－淀粉酶与TP络合后，在不同温度，不同pH值，不同底物浓度的活性变化。结果表明：茶多酚对米曲霉α－淀粉酶无活性抑制作用，两者之间具有起混作用；0．3％的茶多酚浓度，获得最大α－淀粉酶活性回收率（约71％）；α－淀粉酶与TP络合后，阳适反应温度由30－50℃范围变为60－70℃；最适pH值由3．0－8．0变为5．0－6．0；在80℃下，活性变化总趋向与游离的α－淀粉酶；180min后能够保85％的酶活力，但是在前40min，酶活力下降较快；Lineweever-Burk图表明，络合后的α－淀粉酶Km由0．18％变为1．03％（可溶性淀粉底物浓度）。结论：米曲霉α－淀粉酶与TP络合后活性不受抑制并可通过这种络合回收，络合后的α－淀粉酶，最适反应温度及最达pH值变大，变窄，对底物的亲和力下降。     

香柚瓣贮藏保鲜技术研究

运用保鲜剂、低温、简易气调、辐照等综合措施对去皮香柚瓣贮藏技术进行了初步研究。结果表明：香柚去皮分瓣后，用0．15％山梨酸钾和0．15％苯甲酸钠的酸性溶液浸渍，用0．6％的CaCl2和0．5％的酶藻酸钠被膜，再用纸包装，经Co^60辐射处理，柚瓣在3－4℃下可贮藏35d。     

麦麸制备膳食纤维的工艺研究

以麦麸为原料，采用生物法制备膳食纤维。正交试验结果表明，提取膳食纤维的最佳工艺参数为：混合酶制剂的用量为0．2％，α－淀粉酶：糖化酶＝1：3，混合酶解温度65℃，蛋白酶用量为0．3％，酶解时间60min，酶解温度60℃，在此工艺条件下，纤维素得率为66．26％，成品为淡黄色，气味淡，其溶胀性达6．88％（mL/g)，特水力为7．3581％。     

酿造酵母的应用研究——不同酶作用对固形物和蛋白回收物以及风味特性的影响

从啤酒厂的酿造酵母中得到酵母萃取物，这个过程包括了胞内蛋白酶，胞外蛋白酶，5‘-磷酸二脂酶和腺苷一磷酸（AMP）－脱氨酶在内的组合酶作用。酶的组合方式，酶的用量，作用的次序，这些都会对固形物和蛋白回收物，风味特性产生影响，都属于研究的内容。胞外蛋白酶对蛋白质的分离，水解（DH）的程度和感官特征具有非常大的影响；使用最佳的胞内蛋白酶和胞外蛋白酶组合（0.6%Protamex^TM和0.6%Flavourzyme^TM)作用酵母细胞，就可以得到高含量的固形物（48．5％－53．1％）和最佳的风味。在多种酶的不同作用次序中，先蛋白酶后核苷酶的作用可以得到浓度最高的5‘- 鸟苷一磷酸（5‘-GMP)。5‘－磷酸二脂酶和AMP－脱氨酶的最佳用量都皆为0．03％。在使用最佳酶组合，包括四种酶的酶用量和作用次序，可以得到最高的固形物产率55．1％和最高的5‘－核苷酸浓度3．67％。     

柚苷酶在柑桔果醋加工中的应用

在柑桔果醋加工中,利用柚苷酶进行脱苦实验,结果表明：发酵温度在25℃-28℃,酸度控制在0．5－0．8 /100mL,柚苷酶加量在15μ/mL,柚苷酶有较佳的活性;酒精度为6．0％－8．0％（V）时,有利于醋酸发酵,制得的果醋清亮透明,酸甜可口,果香明显,基本无苦味。     

大麦型饲粮中添加GXC酶对生长肥育猪生长、消化的影响及其机理探讨注

选择90头体重约33kg的“杜长大”杂交仔猪，按饲养试验要求分成3组，其中一组饲喂玉米－豆粕型饲粮，另外二组分别饲喂含0和0．2％GXC的大麦－豆粕型饲粮，进行了为期84天的饲养试验，在试验后期进行了消化试验、采样分析。饲养试验结果显示，添加GXC使日增重提高了7．19％（P＜0．01），料重比降低了8．77％（P＜0．05）；消化试验表明，饲粮中添加GXC酶饲料干物质、粗脂肪和粗蛋白的表观消化率分别提高了26．84％（P＜0．01）、14．97％（P＜0．05）和16．5％（P＜0．01）。添加GXC使十二指肠内容物粘度、粪中大肠杆菌数、腹泻频率分别较大麦对照组降低了12．27％（P＜0．05）、53．10％（P＜0．05）和47．39％（P＜0．05）。消化性能指标分析显示，添加GXC酶组十二指肠内容物总蛋白水解酶活性、脂肪酶活性较大麦对照组提高了1．65倍（P＜0．05）和2．94倍（P＜0．05），空肠绒毛的高度及绒毛高度比分别提高了54．17％（P＜0．05）和1．61倍（P＜0．05）。     

黑曲霉固态培养生产纤维素酶的研究

黑曲霉突变株ＤＭ－１是一株产纤维素酶菌株，其中β葡萄糖苷酶活性特别高。采用粗纤维原料固体培养，发酵９６小时（培养温度３１℃），其滤纸酶活和β葡萄糖苷酶活分别为９５和１２００ｍｇ葡萄糖／ｇＤＭｈ。本试验系统研究了各种营养成份和培养条件对ＤＭ－１菌株产纤维素酶的影响。最适发酵培养基为：稻草杆（或麦杆）∶麦麸为６０∶４０、硫酸铵３．０、硫酸镁０．３、玉米浆３．０，加水２００％，自然ｐＨ；环境湿度８５％－９０％。酶反应最适温度和ｐＨ分别为５５℃－６０℃和ｐＨ５．０。酶ｐＨ稳定性较好，在ｐＨ３．０－８．０范围内处理１小时，残余酶活力在８５％以上，该酶经５５℃处理３０ｍｉｎ，剩余酶活力为８６．０％。     

适用于食品工业中的蔗糖-葡萄糖双功能生物传感分析仪的研究

由固定化蔗糖转化酶（INV），葡萄糖变旋酶（MUT）及葡萄糖氧化酶（GOD）的复合酶膜组成的过氧化氢双电极系统，可同时测定样品中蔗糖和葡萄糖的含量，蔗糖电极的葡萄糖干扰用差分法消除。每次进样量25μl，响应时间30s，蔗糖在0－400mg/dl，葡萄糖在0－200mg/dl范围内具有良了的线性关系，连续测定20次蔗糖和葡萄糖的变异系统分别为1．13％和1．05％。蔗糖测定回收率为99．62％－100．97％，蔗糖酶膜使用寿命半个月。     

出芽短梗霉XYE-7木聚糖酶的酶学性质

用固体平板法从果园土壤中分离出一株产木聚糖酶活力较高的类酵母真菌出芽短梗霉XYE-7。此茵的最佳产酶条件为：硫酸铵0．5％、0．2％的酵母膏、磷酸二氢钾0．1％、硫酸镬0．05％、木聚糖0．5％，初始pH值2．0，最适产酶温度是35℃，培养72h后发酵液酶活最高。该酶作用的最适温度是70℃，最适pH值为7．0。     

酶法水解文蛤肉的研究

以海产文蛤肉为原料，用酶水解获得复合氨基酸水解液。水解液中含有１８种氨基酸，牛磺酸，多种维生素及微量元素，酶水解的最适条件为：水解时间４－６ｈ、温度５０－５５℃，初始ｐＨ７．０，酶添加量１．５－２．０％。酶解后，游离氨基酸含量可达５４．６２ｍｇ／ｇ鲜文蛤肉，其中必需氨基酸占５０％以上，牛磺酸为２６６ｍｇ／ｇ鲜文蛤肉，蛋白质的水解率为５６．７８％。     

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