改性玉米醇溶蛋白对速冻水饺质量的影响

添加改性玉米醇溶蛋白到小麦粉中制作速冻水饺,与玉米醇溶蛋白和空白组的速冻水饺的质量作对比,研究添加改性玉米醇溶蛋白后速冻水饺的外观、煮后外观、口感、耐煮性、冻融性、冻裂率及烹煮损失率,并做出综合评价.结果表明:与空白组相比,2种添加剂对水饺质量的影响都较显著,其中改性玉米醇溶蛋白的作用效果比玉米醇溶蛋白好;添加1.5％的改性玉米醇溶蛋白,可以显著降低水饺的冻裂率,对烹煮损失率影响不明显,提高水饺的感官品质和冻融性,明显改善速冻水饺的质量.     

丙三醇对玉米醇溶蛋白流变性和黏结性的影响

为了探明改性玉米醇溶蛋白的流变性和黏结性及其相互关系,研究了丙三醇、温度、剪切速率等对玉米醇溶蛋白流变性和黏结性的影响。结果表明,丙三醇改性的玉米醇溶蛋白具有假塑性流体特性,呈现"剪切变稀"现象。丙三醇含量、剪切温度和剪切速率对玉米醇溶蛋白的流变性有显著影响。随丙三醇含量的增加,玉米醇溶蛋白的黏度明显增加;随剪切温度的增加,黏度呈先下降后增加的趋势,当温度为308 K时,黏度最低;随剪切速率的增加,黏度呈下降趋势。随丙三醇含量的增加,改性玉米醇溶蛋白对竹颗粒的黏结性呈先增加后下降的趋势,当丙三醇体积分数为10%时,黏结性较佳。改性玉米醇溶蛋白的黏度逐渐增加时,其黏结性呈先增加后减小趋势。     

酶法糖基化修饰对玉米醇溶蛋白物化性质的影响

以D-氨基半乳糖为酰基受体,转谷氨酰胺酶为催化剂,对玉米醇溶蛋白进行酶法糖基化改性,分析了D-氨基半乳糖的共价结合对玉米醇溶蛋白物化性质的影响。实验结果表明:与玉米醇溶蛋白相比,糖基化玉米醇溶蛋白的乳化活性/乳化稳定性、起泡性/泡沫稳定性和体外消化能力均增加,而持水性和吸油性下降。在剪切速率为(1~100)s—1条件下,糖基化玉米醇溶蛋白分散液的表观黏度最高,并且表现出剪切稀化特性;在频率为(0.1~10)Hz条件下,交联玉米醇溶蛋白和糖基化玉米醇溶蛋白分散液的弹性模量均大于黏性模量,表现为类固体特征。     

微波改性蛋白复合膜的制备及性质研究

以大豆分离蛋白和玉米醇溶蛋白为原料,通过对玉米醇溶蛋白进行微波改性后制备微波改性蛋白复合膜。选择大豆分离蛋白液与改性玉米醇溶蛋白液体积比、乙醇添加量、成膜液pH值及水浴温度为考察因素,以复合膜的机械性能(抗破强度与断裂距离)为目标值进行单因素试验,并对最佳成膜条件下制得的微波改性蛋白复合膜的微观结构、热特性以及FT—IR进行分析。结果表明:大豆分离蛋白液与改性玉米醇溶蛋白液体积比为3∶1、无水乙醇添加量20%、成膜液pH值12、水浴温度80℃条件下,微波改性蛋白复合膜的抗破强度为2 900g,断裂距离为16.08cm;复合膜具有很好的表观特征和热稳定性,分子间相互作用紧密,其二级结构具有蛋白质的典型特征。     

玉米醇溶蛋白菊粉糖基化改性成膜工艺及其性能研究

以菊粉作为羰基供体,与玉米醇溶蛋白的氨基进行糖基化反应,探讨改性成膜的最佳工艺,并对膜的各种性能进行了检测。结果表明:当物料比(蛋白/糖)10:1(g/g),反应溶液pH 6,反应时间48 h制得的玉米醇溶蛋白—菊粉共价交联膜达到最佳状态,该条件下膜的抗拉强度为10.12 MPa,接枝度为37.5%。改性后的玉米醇溶蛋白膜的透光率、阻水、阻油、阻氧性均优于原玉米醇溶蛋白膜。     

碱性蛋白酶提高玉米醇溶蛋白乳化性的研究

采用Alcalase水解玉米醇溶蛋白以提高其乳化性,通过单因素实验对水解条件进行优化,研究了底物浓度、反应温度、加酶量、pH及水解时间对玉米醇溶蛋白乳化性的影响。实验得出最佳反应条件为底物浓度2%,反应温度45℃,加酶量2200U/g,pH8.0,反应时间80min。所得产物的乳化性为0.558,与未经水解的玉米醇溶蛋白乳化性相比提高了5.26倍。      

葡萄糖糖基化改性玉米醇溶蛋白膜的物化性质 及在胶囊壳中的应用

以葡萄糖为原料对玉米醇溶蛋白进行糖基化改性,以抗拉强度为指标,考察最佳改性成膜工艺,并通过差示扫描量热法(DSC)、傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)对改性蛋白膜的物化性质进行研究。结果表明:在葡萄糖与玉米醇溶蛋白质量比1∶10、超声功率450 W、反应时间30 min的条件下,制得玉米醇溶蛋白-葡萄糖膜的抗拉强度达到34.06 MPa,接枝度为63.05%。玉米醇溶蛋白以共价键的方式与葡萄糖结合,使糖基化改性产物结构更加稳定。改性蛋白膜的表面较改性前更加平整,凹陷凸起基本消失。玉米醇溶蛋白-葡萄糖膜热变性温度从改性前的157.95℃升高到164.26℃,膜的热稳定性提高。经葡萄糖糖基化改性后的玉米醇溶蛋白胶囊壳指标符合《中华人民共和国药典》(2015版)要求。     

湿法糖基化改性玉米醇溶蛋白的物化特性及其在胶囊壳中的应用

利用麦芽糖浆对玉米醇溶蛋白进行湿法糖基化改性,以抗张强度为指标,考察改性后蛋白膜的机械性能,通过SDS-PAGE、DSC、傅里叶红外和扫描电子显微镜等手段考察蛋白改性前后的物化性质。结果表明:改性后蛋白膜较传统的明胶膜和纯玉米醇溶蛋白膜机械性能有较大提高。对SDS-PAGE电泳谱图分析可知玉米醇溶蛋白与麦芽糖浆进行了有效的糖基化接合。经傅里叶红外光谱扫描,可知改性后的玉米醇溶蛋白的化学结构发生了变化。差示量热扫描仪分析表明湿法改性的产物zein-MS膜热变性温度从由为改性前的188. 47℃提高到了206. 87℃,增加了膜的稳定性。扫描电子显微镜发现改性后膜的表面较改性前更加平整,孔洞基本消失。将玉米醇溶蛋白改性产物制成胶囊壳,以常规明胶胶囊壳作对照,参考《中华药典》(2015版)的相关检测指标进行检测,各项指标均合格。     

高碱性条件下醇法大豆浓缩蛋白的改性

醇法大豆浓缩蛋白在高碱性条件下溶出,再经过高压均质和闪蒸改性,测定了改性前后大豆蛋白的NSI、凝胶性和乳化性.结果表明,改性后大豆浓缩蛋白的溶解度增加,功能特性有不同程度的改善.     

玉米醇溶蛋白在食品中的应用

玉米醇溶蛋白是玉米中储存蛋白的主要成分之一,约占玉米蛋白的70%左右。概述了玉米醇溶蛋白的组成以及结构;讨论了其在食品方面的应用,包括改性方法增加玉米醇溶蛋白的黏弹性,制作无面筋食品,作为食品包埋剂、可降解塑料,也可以在食品中作为乳化剂使用;总结了玉米醇溶蛋白的应用现状,并对其发展前景进行展望。     

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