限制性酶解结合大孔树脂吸附对葵花籽蛋白色泽及功能特性的影响

以低温脱脂葵花籽粕为原料提取葵花籽蛋白,对其分别进行大孔树脂吸附脱色和限制性酶解结合大孔树脂吸附脱色处理,对比不同处理的葵花籽蛋白白度值、绿原酸含量及功能特性(溶解性、乳化性、乳化稳定性、起泡性、泡沫稳定性、持油性、持水性和凝胶性)的差异。结果表明:限制性酶解10 min结合大孔树脂吸附脱色的葵花籽蛋白白度值(L^*)为86.3,绿原酸含量为0.16 mg/g,溶解性为77.60%,起泡性为20.87%,乳化性为3.44 m²/g,乳化稳定性为118.51 min,均显著优于葵花籽蛋白和大孔树脂吸附脱色葵花籽蛋白(P <0.05),持水性为1.94 mL/g,显著优于葵花籽蛋白,但与大孔树脂吸附脱色葵花籽蛋白相当,持油性和泡沫稳定性分别为4.40 mL/g和69.62%,显著低于葵花籽蛋白和大孔树脂吸附脱色葵花籽蛋白,限制性酶解10 min结合大孔树脂吸附脱色葵花籽蛋白展现出较好的凝胶性。研究表明,经限制性酶解结合大孔树脂吸附脱色后,葵花籽蛋白色泽显著改善,其溶解性、乳化性、起泡性、持水性和凝胶性均显著提高。     

葵花籽蛋白脱色工艺的研究

用常规方法提取的葵花籽蛋白颜色呈深灰色,严重影响其在食品中的应用,为此研究了葵花籽蛋白的脱色工艺,旨在制备浅色葵花籽蛋白。以低温脱脂葵花籽粕为原料,利用限制性酶解后再结合大孔树脂对葵花籽蛋白进行吸附处理,探讨其对葵花籽蛋白脱色效果的影响。以吸附温度、pH、吸附时间、树脂添加量为考察因素,以葵花籽蛋白的L*值为评价指标进行正交试验。结果表明：碱性蛋白酶结合AB-8型大孔树脂吸附后葵花籽蛋白的脱色效果最佳,葵花籽蛋白的最佳脱色工艺条件为pH 7.0、吸附温度20 ℃、吸附时间120 min、树脂添加量12%;在最佳脱色工艺条件下,葵花籽蛋白的L*值为86.3、a*值为2.6、b*值为10.7,脱色葵花籽蛋白为浅白色,质地柔软细腻,脱色效果显著,其蛋白质含量和得率分别为97.50%和8.50%。     

超声波辅助大孔树脂提取浅色葵花籽蛋白工艺的研究

以低温脱脂葵花籽饼为原料,通过超声波辅助大孔树脂处理方法提取浅色的葵花籽蛋白。以L^*值作为指标,采用单因素正交实验来优化最佳工艺条件。在此基础上,研究了该处理方法对葵花籽蛋白得率和功能特性的影响。结果表明：制备浅色葵花籽蛋白的最佳工艺条件为料液比1∶20 g/mL、超声功率200 W、超声时间25 min和树脂添加量10%。在此条件下葵花籽蛋白的L^*值高达82.87。与未处理的葵花籽蛋白相比提高了32.79%;超声波辅助大孔树脂吸附处理后葵花籽蛋白的得率、溶解性、乳化性、乳化稳定性、起泡性和持水性均显著改善(P<0.05),分别提高了33.27%、19.04%、0.95 m²/g、0.73 min、6.04%、0.65 g/g。综上所述,超声波辅助大孔树脂处理可以改善葵花籽蛋白的色泽和功能特性。     

凤尾鱼酶解产物脱腥脱色工艺优化

凤尾鱼酶解物(AFH)通过大孔树脂吸附处理后,发现DA201-C型大孔树脂为最佳吸附材料。在单因素实验基础上,以腥味、色泽和回收率为评价指标,运用正交实验L₉(34)优化了DA201-C型大孔树脂对凤尾鱼酶解产物脱腥脱色工艺,得到最佳条件为:pH6,大孔树脂量5%,脱腥脱色时间1.5 h,以及温度25℃,该条件下感官评定综合评分为84.36。同时,研究表明脱腥脱色后,凤尾鱼酶解产物中牛磺酸、丙氨酸、甲硫氨酸和异亮氨酸呈显著性降低(P<0.01),挥发性物质成分中醛和含氮类化合物相对含量呈显著性降低。     

限制性酶解对亚麻籽蛋白功能特性、结构的影响及其在冰淇淋中的应用

本文研究了限制性酶解对亚麻籽蛋白功能特性及结构的影响,进一步研究了其在冰淇淋中的应用。结果表明,限制性酶解能显著提高亚麻籽蛋白的溶解性,酶解时间越长溶解性越好;但对亚麻籽蛋白的乳化性及乳化稳定性、起泡性及泡沫稳定性、持油性来说需要适度的水解,限制性酶解时间为5min时乳化稳定性、泡沫稳定性、持油性达到最高,限制性酶解时间为10min时乳化性和起泡性达到最高;但限制性酶解会削弱亚麻籽蛋白的持水能力。同时发现亚麻籽蛋白经限制性酶解后粒径较小的分子增多,平均粒径降低;表面巯基含量及表面疏水值均呈先增加后降低趋势,表明适度的限制性水解使其结构展开暴露出先前埋在蛋白质内部的巯基及疏水基团;圆二色谱分析结果显示,经限制性酶解其α-螺旋和无规则卷曲的含量增加,β-折叠和β-转角的含量下降,表明其二级结构发生改变更具柔韧性;扫描电镜分析结果发现经限制性酶解由较大平滑片状变成了较小松散碎片状。添加限制性酶解亚麻籽蛋白制作冰淇淋,随着其添加量的增加感官品质先上升后下降,添加量为4%时感官评分值达最高为85.0分,同时还发现随着添加量的增加其膨胀率显著上升、融化率显著下降、融化后其大气泡数量呈增加趋势,表明添加4%的限制性酶解亚麻籽蛋白可获得品质较好的冰淇淋。以上结果表明限制性酶解改变了亚麻籽蛋白结构,使其具有较好的功能特性,可添加在冰淇淋中。     

优化蚕蛹多糖的提取方法及脱色工艺的研究

目的:优化蚕蛹多糖的提取工艺及对蚕蛹多糖的脱色条件的研究。方法:采用正交实验方法,以蚕蛹多糖的得率为指标,优化微波法对蚕蛹多糖的提取工艺。研究离子交换树脂(D202、D113)和大孔吸附树脂(HZ-841、HZ-806、HZ-803)对蚕蛹多糖的脱色效果。通过正交实验确定蚕蛹多糖脱色的最佳条件。结果:传统工艺提取最佳条件:90℃提取3.5h,固液比1∶25g/mL,蚕蛹多糖的得率为3.95%;微波提取蚕蛹多糖的最佳工艺条件:微波功率600W,提取时间9min,固液比1∶25g/mL,蚕蛹多糖的得率为4.49%。蚕蛹多糖大孔树脂脱色的最佳条件为HZ-803树脂、pH4.0、温度45℃。结论:优化之后的微波提取法提取蚕蛹多糖的得率有显著的提高,且工艺简便、合理、可行,在大孔树脂静态吸附最佳脱色的条件下脱色率、多糖保留率和蛋白质去除率分别为88.56%、62.15%、92.21%,在大孔树脂动态吸附最佳脱色的条件下脱色率、多糖保留率和蛋白质去除率分别为89.43%、65.58%、90.56%。     

脱色工艺对鱼皮胶原肽品质的影响

利用复合酶通过酶解方法制备罗非鱼皮胶原肽,考察活性炭、大孔吸附树脂对胶原肽的脱色效果。以脱色率和肽损失率为指标,通过正交试验进行工艺优化,结果表明:在pH 4.5、活性炭添加量2%(m/V)、脱色时间60min、蛋白浓度50mg/mL的条件下,活性炭脱色效果最佳,脱色率可达92.66%,肽损失率为11.23%;而大孔吸附树脂在最佳脱色条件下,脱色率只有83.02%,肽损失率却高达30.77%,脱色效果明显不及活性炭。根据胶原肽分子量分布和氨基酸组成分析结果发现:经活性炭、大孔吸附树脂脱色后,鱼皮胶原肽中分子量500~1 000Da组分比例明显减少,His、Tyr和Phe等氨基酸含量显著下降。     

血球蛋白粉酶解的关键工艺参数研究

用血球蛋白粉为原料,以水解率、蛋白得率和脱色效果为评价指标,对制备酶解蛋白粉的工艺参数进行了研究.结果表明,反应条件控制在温度50 ℃、酶活5 000 u/g底物和反应pH值8时,血球蛋白粉能够得到很好的酶解,并获得较好的蛋白得率.同时表明,脱色液pH控制在4、活性炭用量0.2 g/100 mL、温度控制在50℃和吸附时间60 min时,能够达到理想的脱色效果和较高的蛋白得率.     

河蚬多肽的制备工艺

以酸溶性多肽得率(TCA-SN)为指标,研究河蚬多肽的制备工艺.比较了中性蛋白酶Neutrase、复合蛋白酶Protamex、碱性蛋白酶Alcalase和木瓜蛋白酶Papain对河蚬蛋白的水解效果,考察了加酶量、p H、温度、时间、底物浓度五种因素对Alcalase碱性蛋白酶酶解过程的影响,采用正交实验优化法确定碱性蛋白酶Alcalase最佳酶解工艺条件为:酶解温度55℃,加酶量3%,底物浓度2%,起始p H8.5,酶解时间为3 h;在此条件下酸溶多肽的得率为29.65%。再利用大孔树脂吸附法对河蚬多肽进行分离,比较SQD-67、DA201-A、DA201-DⅡ、DA201-M和DA201-H几种树脂对河蚬多肽的吸附性能,最终确定大孔吸附树脂DA201-C的最佳吸附条件为:上样流速1 BV/h,上样浓度30 mg/m L,乙醇洗脱浓度为75%,洗脱液经减压浓缩、冷冻干燥得到河蚬多肽,其纯度为82.19%。     

超声波对脱色葵花籽蛋白色泽和功能特性的影响

本实验研究了超声波(200、400、600 W,30 min)技术对脱色的葵花籽蛋白色泽和功能特性的影响.结果表明,与未处理的葵花籽粕蛋白相比,经超声波处理后脱色葵花籽蛋白的溶解度、持水性、乳化性、起泡性和持油性均显著改善(P＜0.05).其中超声功率为400 W时葵花籽蛋白的亮度值(L*)由55.7提高至77.3;超...     

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