响应面试验优化超声波辅助提取半枝莲黄酮工艺

采用超声波法辅助提取半枝莲黄酮,以超声波功率、超声温度、提取时间、乙醇浓度为因素,考察各个因素对半枝莲黄酮提取率的影响。结果表明,最佳提取工艺参数为超声波功率400W、超声温度57℃、提取时间49 min、乙醇浓度72%,在此工艺参数下做3次平行试验,半枝莲黄酮提取率为96.25%。方差分析结果表明,影响半枝莲黄酮提取率大小因素依次为超声温度超声波功率提取时间乙醇浓度。     

不同紫苏油粕黄酮提取方法的比较研究

探究乙醇提取法、超声波法、微波辅助法,3种不同提取方法对紫苏油粕黄酮提取率的影响。结果显示:乙醇提取法的最佳工艺条件为料液比1∶30(g/mL),乙醇浓度60%,提取时间30 min,提取率可达1.97%;超声波法的最佳工艺条件为料液比1∶30 (g/mL),乙醇浓度60%,超声功率600 W,超声时间30 min,提取率可达2.90%;微波辅助法的最佳工艺条件为料液比1∶20 (g/mL),乙醇浓度60%,微波功率500 W,提取时间11 min,提取率可达3.04%。从提取率、提取液用量、时间等方面进行比较分析:微波辅助法优于超声波法和乙醇法,超声波法又优于乙醇法。     

超声波辅助提取梵净山黑茶多酚工艺的优化

在单因素试验的基础上,选取料液比、乙醇浓度、超声功率、超声时间利用正交试验优化超声波辅助提取梵净山黑茶多酚的工艺。试验结果表明,影响黑茶多酚提取率的主要因素依次为超声时间、乙醇浓度、料液比、超声功率。通过分析得出:料液比1∶12(g/m L)、乙醇浓度60%、超声功率350 W、超声时间40 min为最佳提取条件。对最佳提取条件进行验证,得出梵净山黑茶多酚提取率为7.22%。     

夏枯草总黄酮超声提取工艺

研究超声波辅助提取夏枯草总黄酮的最佳提取工艺条件。考察乙醇浓度、料液比、提取温度、超声功率及提取时间对夏枯草总黄酮提取率的影响,并在此基础上采用响应面分析法对提取工艺进行优化。以上因素对夏枯草总黄酮的提取率都有一定的影响,最佳提取工艺条件如下:乙醇浓度为60%;料液比为1∶12(g/mL);提取温度为61.4℃;超声功率为150 W;提取时间为40 min。在此条件下,夏枯草总黄酮的提取率可达到7.92%。     

超声波提取北冬虫夏草多糖的工艺

以北冬虫夏草为原料,以虫草多糖为研究对象,以虫草多糖提取率为指标,使用超声渡提取,探讨乙醇浓度、超声波功率、提取时间、料液比对多糖提取率的影响;采用正交实验设计对提取工艺条件进行优化,结果表明最佳提取工艺条件为溶剂60%乙醇、超声波功率250 W、提取时间13 min、料液比1:35(g/mL),在此条件下进行的验证实验多糖提取率为25.89%.     

超声波萃取苦荞麸皮中总黄酮的工艺研究

以苦荞麸皮为原料,研究了超声波萃取苦荞麸皮中的黄酮时各因素对总黄酮提取率的影响,影响次序为超声时间>乙醇体积分数>料液比,超声波提取苦荞麸皮黄酮的较优组合为乙醇体积分数70%,超声时间40min,料液比为1:40,在最佳条件下黄酮提取率为89.19%。     

超声波辅助提取桑椹色素的技术研究

对超声波辅助提取桑椹色素的方法进行比较系统的研究,同时采用正交试验对该方法进行优化,得到了超声波辅助提取桑椹色素的最佳工艺参数为0.01%HCl-70%乙醇、超声波功率为140 W、超声波处理时间为45 min、料液比(mL/g)为1:15,桑椹色素提取率为75.64%;其中各因素对超声波辅助提取桑椹色素的影响作用大小为料液比>乙醇浓度>超声功率>超声时间。     

超声波提取杏鲍菇三萜类化合物工艺的研究

在单因素试验的基础上,利用响应曲面设计(Response surface methodology,RSM)系统研究乙醇浓度、超声波功率、超声时间和料液比等因素对杏鲍菇三萜类化合物提取率的影响。确定超声波辅助提取杏鲍菇三萜类化合物的最佳工艺条件为:乙醇浓度88.20%、超声波功率为207.40 W、超声时间为33.19 min、料液比1∶25。最佳条件下三萜类化合物的提取率可达到16.832%。     

超声波辅助提取大球盖菇总黄酮工艺优化

主要研究了超声波辅助提取大球盖菇中总黄酮的提取工艺,研究了乙醇浓度、超声功率、时间、料液比对大球盖菇总黄酮提取率的影响。通过单因素试验和正交试验确定了大球盖菇黄酮类化合物的优化提取工艺条件。超声波优化提取工艺条件为:乙醇浓度30%,料液比1∶15(g/m L),超声功率120 W,时间1 h,总黄酮的提取率为1.138%。     

大豆乳清废水异黄酮的超声波乙醇萃取

为提高大豆乳清废水的利用率,对废水中的异黄酮进行超声波乙醇萃取。相关研究结果表明,大豆乳清废水异黄酮的最佳提取工艺条件为:提取时间30min、超声波功率450W、料液比16∶1、乙醇浓度70%。在此工艺条件下,异黄酮的提取率高达到0.661%。提取时间对异黄酮提取率具有显著影响,是大豆乳清废水异黄酮提取率的关键性影响因素。     

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