响应面法优化微波辅助提取普洱茶中茶色素工艺研究

研究云南普洱茶中茶色素的提取工艺。采用微波辅助提取方法,在研究提取时间、料液比、微波功率及提取次数等单因素试验基础上,进行二次正交旋转组合试验,采用响应面法分析和典型性分析,确定普洱茶中茶色素的最优提取工艺。结果表明：提取时间对提取得率有极显著影响(P ＜ 0.01),微波功率对提取得率有较显著影响(P ＜ 0.05),而料液比对提取得率的影响不显著,最优化的提取工艺为提取时间9.48min、微波功率640W、料液比1:58.79,在该条件下进行微波辅助提取,普洱茶中茶色素的提取得率能达到理论预测值的97.5%。     

三叶委陵菜黄酮的微波辅助提取工艺研究

研究三叶委陵菜中黄酮类物质的微波辅助提取工艺,采用微波辅助提取法提取了三叶委陵菜黄酮,考察乙醇浓度、微波功率、提取时间、回流温度、料液比对三叶委陵菜提取液中黄酮含量的影响,确定了微波萃取仪提取三叶委陵菜黄酮的最佳工艺条件为:以75%乙醇作溶剂,在料液比为1∶25(g/mL),温度70℃,功率400 W的条件下微波提取5 min,效果最好,提取液中总黄酮含量为4.24%。     

微波辅助提取香椿叶黄酮工艺的研究

比较微波辅助甲醇提取香椿黄酮与乙醇提取、甲醇回流和乙醇回流等工艺提取香椿黄酮的效果,用正交设计筛选微波辅助乙醇提取工艺条件,并探讨材料的液料比、体积分数、微波处理时间、微波功率对提取效果的影响,结果表明:微波辅助甲醇提取和乙醇提取效果明显优于其它传统方法;最佳工艺条件:液料比25 mL/g,乙醇体积分数70%,微波功率400 W,处理15 min。此工艺提取率达到70.15%,是一种高效、节能的提取香椿黄酮的工艺。     

微波萃取在菊花黄酮提取工艺中的应用研究

在微波单因素提取的基础上采取L9(34)正交优化试验,探讨乙醇浓度、微波提取时间和料液比对菊花黄酮提取率的影响.经过单因素试验及正交试验,结果表明:影响菊花黄酮微波提取的主要因素为乙醇浓度,其次为提取时间、料液比.在微波功率300 W的条件下,最佳提取工艺条件为乙醇浓度60%,提取时间120 s,料液比1∶20.此时总黄酮提取率为4.83%.     

响应面法研究β- 环糊精微波协同提取甘草黄酮的工艺研究

用β-CD微波协同提取甘草中的黄酮,在单因素试验基础上采用响应面(RSM)分析法,考察β-CD用量、微波功率、料液比、微波时间、乙醇体积分数、对黄酮提取率的影响。单因素试验确定最佳提取条件为:甘草∶β-CD(质量比)为1∶0.8、微波功率200 W、料液比1∶30(g/mL)、微波提取时间150 s、乙醇体积分数60%;响应面法试验优化结果为:微波功率200 W、微波提取时间145 s、料液比1∶32(g/m L)。     

响应面法优化微波辅助提取芦笋黄酮的研究

以绿芦笋为原料,在单因素试验的基础上,选取液料比、微波功率和提取时间为影响因子,以黄酮得率为响应指标,采用响应面试验设计和分析的方法对微波辅助提取芦笋黄酮的工艺进行了优化。结果表明,微波辅助提取芦笋黄酮的最佳工艺参数为:液料比3∶1,微波功率309W,提取时间120 s,黄酮得率为0.695%。与常规溶剂提取法和超声提取方法相比,微波辅助提取法显著提高了芦笋黄酮的得率,大大缩短了提取时间。因此微波辅助提取法在植物黄酮的提取中有很大的应用前景。     

响应面法优化微波辅助提取艾草黄酮工艺

以艾草为原料,通过单因素试验和响应面试验设计优化微波辅助提取黄酮工艺,分别考察了乙醇浓度、液料比、微波功率、微波时间对黄酮得率的影响。结果表明,最优工艺条件为:乙醇浓度72%、液料比45∶1(g/m L),微波功率520 W,微波时间151 s,在此工艺条件下,艾草黄酮得率为4.37%。     

花椒黄酮的微波提取及抗氧化活性研究

利用微波法提取了花椒黄酮,得率为11.78%。考察了乙醇浓度、料液比、微波功率、提取温度和时间对花椒黄酮得率的影响,测定了花椒黄酮的抗氧化性能,并与抗氧化剂Vc做比较。结果表明,微波提取花椒黄酮的最佳条件:温度60℃,乙醇浓度70%,料液比1:35,微波功率400W,提取时间5min。花椒黄酮在清除羟自由基和对卵黄蛋白脂质抗氧化能力比Vc强,总抗氧化活性、清除超氧阴离子和清除DPPH自由基的能力比Vc弱。     

玫瑰叶黄酮提取及其对亚硝酸盐的清除作用

以乙醇为提取剂,采用微波法提取玫瑰叶黄酮,探讨乙醇浓度、固液比、颗粒粒度、微波功率、微波时间对玫瑰叶黄酮提取率的影响.结果表明;乙醇浓度、固液比和微波时间对玫瑰叶黄酮提取率影响较大,而颗粒粒度的影响较小.在微波功率为136 W时,玫瑰叶黄酮的最佳提取工艺务件为:乙醇浓度70%(V:V),固液比1:50(W:V),颗粒粒度40目,微波时间1.0 min.此条件下,玫瑰叶黄酮提取率为3.98%.同时研究表明,玫瑰叶黄酮对亚硝酸盐具有很强的清除能力,当黄酮添加浓度为0.12 mg/mL时,清除率可达67.9%,与0.04 mg/mL的Vc效果相当.     

微波提取红花黄酮类化合物的研究

对红花黄酮类物质的微波提取工艺进行了探讨。采用单因素试验与正交试验,分别考察了乙醇浓度、微波时间、微波功率、微波温度及料液比对红花黄酮类化合物提取率的影响。试验结果表明,最佳的提取条件为乙醇浓度60%vol,料液比1∶35,微波功率800W,提取时间25min,提取温度50℃,提取2次。在此条件下,红花黄酮的提取率达到10.23%。     

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