响应面优化超声波辅助水酶法提取花生蛋白工艺

采用水酶法结合超声波预处理提取花生蛋白,在单因素实验基础上,选出最优的超声时间和超声温度,重点以酶用量、酶解pH、酶解温度、酶解时间和料液比为考察的影响因子,花生蛋白提取率为响应值。确定最优复合酶水解的水酶法提取花生蛋白工艺条件为：加酶量为1.59%,温度为56.5℃,酶解时间为3.9h,料水比为1∶4.4,pH为9.0,此时蛋白提取率为94.31%±0.37%。     

复合酶水酶法提取大豆蛋白的工艺优化

采用复合酶水酶法提取大豆蛋白。水解酶选用碱性蛋白酶,复合酶采用纤维酶、半纤维酶、果胶酶。得出最优复合酶水酶法提取大豆蛋白工艺条件为料水比1:6(g/mL)、纤维素酶添加量0.64%、半纤维素酶添加量0.56%、酶解pH5、酶解温度37℃条件下水解0.75h后,再利用Alcalase碱性内切蛋白酶,加酶量1.85%、酶解温度50℃、酶解pH9.26、水解3.6h。经过验证实验可知,在最优酶解工艺条件下总蛋白提取率可达到极大值即85.78%。经过复合酶酶解预处理比传统的湿热预处理的总蛋白提取率提高了近10%,其原因经分析是经过复合酶酶解处理的豆粉其细胞结构充分破坏,使得酶的作用位点暴露更有利于蛋白酶的作用,具体的机理分析有待进一步研究。     

酶辅助法提取脱脂葡萄籽蛋白的工艺研究

采用酶辅助碱溶酸沉法提取脱脂葡萄籽中的蛋白质,探讨酶添加量、酶解时间、酶解温度和酶解pH对脱脂葡萄籽蛋白得率的影响。结果表明:酶添加量为1.5%、酶解时间30 min、酶解温度36℃、酶解pH7.5,此条件下脱脂葡萄籽蛋白得率达31.87%,且影响因素的主次顺序为酶解pH酶解温度酶解时间。对得到的葡萄籽蛋白的溶解性、乳化性、起泡性进行了探讨。     

酶法制备酸浆籽分离蛋白及其功能性质的研究

时酸浆籽分离蛋白的提取及其功能性质进行研究.采用酶提酸沉法制备酸浆籽分离蛋白,通过正交试验确定酶法提取蛋白的最佳工艺条件是:pH 9.0、提取温度55℃、提取时间2 h、加酶量3 000 u/mL,在此条件下提取率达90.6%.所制得的酸浆籽分离蛋白的溶解性较好,并具有一定的保水性、乳化性.为酸浆的深加工奠定理论基础.     

冷榨与温榨花生蛋白粉功能特性的比较

对比研究冷榨和温榨对花生蛋白粉物理化学特性的影响。用压榨温度60℃和80℃对花生进行压榨制备花生蛋白粉,分析2种花生蛋白粉的物理化学特性,包括溶解度、乳化性、起泡性、持水性、持油性;分别采用马尔文Zeta电位仪、色度色差仪分析2种蛋白粉的电势、粒径和色度,采用质构仪测定其制备的豆干的质构特性。结果发现,冷榨花生蛋白粉的溶解性、起泡性和起泡稳定性较好,而温榨花生蛋白粉的乳化稳定性和持水性较好;冷榨花生蛋白粉的白度高于温榨花生蛋白粉;在pH6～7时,温榨花生蛋白粉溶液Zeta电势的稳定性显著高于冷榨花生蛋白粉,而在长期储存方面冷榨花生蛋白粉溶液优于温榨花生蛋白粉溶液,冷榨花生蛋白粉的粒径分布更均匀;冷榨花生蛋白粉制备的豆干硬度显著高于温榨花生蛋白粉豆干,高于大豆分离蛋白豆干。实验结果为花生蛋白粉的应用奠定了理论基础。     

混料设计优化复合酶水解水酶法提取大豆油工艺

利用混料优化设计对最适合水酶法提取大豆油脂的复合酶配比条件和水解条件进行优化,以总油提取率为指标,确定复合酶水解的水酶法提取大豆油脂和蛋白工艺最优条件。结果表明,料水比1:6(g/mL)、纤维素酶添加量0.84%、半纤维素酶添加量0.56%、酶解pH5、酶解温度37℃条件下水解0.75h后,再利用Alcalase碱性内切蛋白酶,加酶量1.85%、酶解温度50℃、酶解pH9.26、水解3.6h,总油提取率达到极大值即81.04%,比以往国内研究采用湿热处理工艺有很大提高。     

核桃分离蛋白的制备工艺优化及功能特性北大核心CSCD

为制备蛋白纯度高于90%的核桃分离蛋白,采用糖化酶纯化核桃蛋白,探究了酶解温度、酶解pH、酶解时间、加酶量和料液比5个因素对核桃蛋白提取率和纯度的影响,并与低变性核桃蛋白粉(由核桃仁仅经过脱脂制备)比较考察其氨基酸组成与功能特性。结果表明,核桃蛋白纯化的最佳工艺条件为:加酶量80 U/g,料液比1∶8,酶解温度55℃,酶解时间40 min,酶解pH 5.0。在最优条件下,蛋白纯度为94.37%。制备的核桃分离蛋白氨基酸组成合理,持水性为3.72 g/g,吸油性为1.57 g/g,乳化性为57.60%,均明显优于低变性核桃蛋白粉。研究证明糖化酶纯化法得到的核桃分离蛋白品质较好。     

米糠油体的酶法提取工艺优化北大核心CSCD

米糠油体作为天然水包油型乳状液,在食品工业中具有良好的应用前景。为提高米糠油体得率及稳定性,采用酶法提取米糠中油体,以米糠油体得率、粒径分布、稳定性及微观结构为指标,考察了木聚糖酶与植物提取酶质量比、复合酶添加量、pH和酶解时间对米糠油体提取的影响。结果表明,米糠油体最优提取条件为木聚糖酶与植物提取酶质量比2∶1、复合酶添加量3%、pH 5.0、酶解温度50℃、酶解时间1.5 h,在此条件下提取的米糠油体得率高,粒径分布集中,粒径达到微米级,且稳定性良好、结构完整。     

酸浆籽蛋白酶解肽的制备及其物化性质的研究

用碱性蛋白酶酶解酸浆籽蛋白制备短肽,以反应体系pH、酶添加量、酶解温度、酶解时间及底物浓度等因素为单因素进行试验,在单因素试验的基础上,设计正交优化试验,研究酸浆籽肽提取的最佳工艺条件。结果显示,反应体系pH为9.0,酶添加量为1000 U/g,酶解温度为50℃,酶解时间为2.5 h,底物浓度为6%,酸浆籽肽的提取率最高,达到53.75%。研究同时考察了酶解得到的酸浆籽肽的溶解性、持水性、乳化能力及乳化稳定性、吸油性等功能性质,结果证实酸浆籽肽在p H为7.0且50℃时的溶解性最大,在40℃时持水性最强,乳化能力及乳化稳定性随p H的增大而增大,吸油性变化幅度则较小。     

复合酶酶解作用对豆粉溶解性的影响

在传统制备豆粉工艺的基础上,采用木瓜蛋白酶、风味蛋白酶和碱性蛋白酶的复合酶酶解豆粉提高豆粉的溶解性。在单因素试验基础上,采用响应面分析法对复合酶酶解工艺制备高溶解性豆粉工艺进行优化,确定最优酶的添加量为1.2%,酶解时间为45 min,酶解温度为60℃,酶解pH值为6。在最优工艺条件下,豆粉的溶解性为89.45%,与传统的豆粉以及单一酶酶解的豆粉溶解性相比提高了近15%,表明复合酶酶解工艺可以显著提高豆粉的溶解性。     

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