蒲桃叶多酚微波辅助提取工艺及抗氧化活性研究

为研究蒲桃叶多酚的微波辅助提取工艺,明确蒲桃叶多酚体外抗氧化活性.在单因素试验基础上通过响应面法优化蒲桃叶多酚的提取工艺,考察乙醇体积分数、液料比、微波功率、微波时间四个因素对蒲桃叶多酚提取率的影响,通过蒲桃叶多酚对DPPH自由基和羟自由基的清除效果来评价其抗氧化活性.结果表明,蒲桃叶多酚最佳提取工艺条件为乙醇体积分数...     

微波辅助萃取法提取葛根总黄酮工艺优化

为优化微波辅助萃取法提取葛根总黄酮工艺,以葛根总黄酮得率为评定指标,采用单因素试验和正交试验,探究乙醇体积分数、料液比、微波处理时间和微波功率对微波辅助萃取法提取干葛根和鲜葛根总黄酮得率的影响。结果表明,微波辅助萃取法提取干葛根总黄酮最佳工艺为料液比1︰25 (g/mL)、微波功率255 W、微波处理时间2 min、乙醇体积分数30%。微波辅助萃取法提取鲜葛根总黄酮最佳工艺为料液比1︰20 (g/mL)、微波功率255W、微波处理时间2.5 min、乙醇体积分数30%。在最佳工艺条件下,干葛根和鲜葛根总黄酮得率分别为(21.7±0.2)mg/g和(6.37±0.05) mg/g。     

超声辅助提取石榴叶中总黄酮工艺的研究

以石榴叶为原料,采用乙醇作为提取溶剂,在超声辅助下提取石榴叶中总黄酮。探讨了超声功率、乙醇体积分数、料液比、提取时间等因素对总黄酮得率的影响。结果表明,超声辅助法从石榴叶中提取总黄酮的适宜工艺条件为：乙醇体积分数70％,功率350W,提取时间16min,料液比1：10。此条件下石榴叶中总黄酮提取得率为0．38％。     

超声波辅助提取祁连圆柏叶总黄酮工艺的研究

研究超声波辅助提取祁连圆柏叶总黄酮的最佳提取工艺条件。以祁连圆柏叶为原料,考察乙醇体积分数、料液比、提取时间、超声功率对其总黄酮提取率的影响,并在此基础上采用L9(34)正交试验设计对提取工艺进行优化。结果表明,总黄酮的最佳提取工艺为:乙醇体积分数90%、料液比1︰20、提取时间40 min、超声功率105 W。     

响应面优化超声-微波协同提取石榴叶中总黄酮工艺的研究

为确定石榴叶中总黄酮提取的最佳工艺,在单因素试验的基础上,应用响应面法优化石榴叶中总黄酮的提取条件。结果表明:微波功率、提取时间和料液比对黄酮提取率影响极显著;最佳工艺为:乙醇体积分数71.5%(v/v),微波功率662 W,提取时间262 s,液料质量体积比33.5g/m L,在此条件下提取1次,石榴叶中总黄酮的提取率为89.21%。     

微波提取无花果叶中的总黄酮及其体外抗氧化活性研究

采用微波法提取无花果叶中的总黄酮,考察乙醇体积分数、液料比、提取功率、提取时间对总黄酮提取率的影响,并进行四因素四水平正交试验,得到总黄酮的最佳提取工艺条件为:乙醇体积分数90%,液料比55∶1(mL/g),提取功率200 W,提取时间3 min,黄酮的含量为20.56 mg/g;该提取物对DPPH自由基去除率达66.67%,羟基自由基去除率达30.49%,证明其具有较好的体外抗氧化能力。     

超声-微波协同提取甘草渣中总黄酮工艺优化

为提高甘草的综合利用,该研究以甘草渣为原料,采用响应面法优化超声-微波协同提取甘草渣中总黄酮的提取工艺条件。考察液料比、微波功率、乙醇体积分数和提取时间对甘草渣中总黄酮提取率的影响,根据响应面试验结果,建立总黄酮提取率的回归方程,获得甘草渣中总黄酮的最佳提取工艺条件为：液料比28.4∶1（mL∶g）、微波功率125 W、超声功率300 W、乙醇体积分数79%、提取时间32 min。在此条件下,甘草渣中总黄酮的提取率为2.59%。     

正交试验法优化卷心菜叶中绿原酸提取工艺研究

以卷心菜叶为原料,研究采用微波法辅助提取卷心菜叶中绿原酸的提取工艺。实验中以绿原酸的提取率为指标,以乙醇为提取剂,考察乙醇体积分数、料液比、微波温度、微波时间、微波强度等因素对卷心菜叶中绿原酸提取率的影响。通过L16(45)正交优化绿原酸提取工艺,结果显示,最佳工艺条件为:微波温度60℃、微波时间6 min、微波功率300 W、乙醇体积分数60%、料液比1∶20。在此最佳工艺条件下,卷心菜叶中绿原酸的提取率为1.2682%。     

刀豆壳总黄酮提取工艺优化及其抗氧化活性研究

以刀豆壳的总黄酮提取量为评价指标,使用乙醇为提取剂,微波辅助提取刀豆壳总黄酮,分别考察乙醇体积分数(%)、液料比(mL/g)、微波时间(min)、微波功率(W)对刀豆壳总黄酮提取量的影响,通过响应面法优化提取工艺并研究提取的刀豆壳总黄酮的抗氧化活性。经试验得出当乙醇体积分数为50%,液料比为20:1(mL/g),微波时间为5.6 min,微波功率为600 W,总黄酮提取量为2.330 mg/g;刀豆壳总黄酮对羟自由基清除作用明显,其质量浓度与抗氧化活性有一定的量效关系。     

微波辅助提取山竹壳中的总黄酮及其体外抗氧化活性研究

采用微波辅助提取山竹壳中的总黄酮类化合物,测定其体外抗氧化活性。考察乙醇体积分数、液料比、微波功率、微波提取时间对总黄酮提取率的影响,并采用四因素四水平正交试验,确定总黄酮的最佳提取工艺条件。结果表明,最佳提取工艺为:乙醇体积分数75%,液料比35∶1(mL/g),微波功率300 W,微波提取时间3 min,此时总黄酮的提取率为12.02 mg/g。试验得出,该提取物对超氧阴离子自由基去除率最高达到72.34%、DPPH自由基去除率最高为68.52%,该提取物具有较好的体外抗氧化效果。     

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