响应面法优化荷叶黄酮超声提取条件的研究

在单因素试验的基础上,利用响应面分析方法优化荷叶中黄酮化合物的超声提取条件.利用中心组合设计研究乙醇浓度、液固比、超声时间、超声温度4个自变量对响应值黄酮得率的影响.用SAS9.0进行结果分析,响应面的典型分析可知稳定点是最大值,决定系数为0.959 8.黄酮最佳超声提取工艺条件为:乙醇浓度61%,液固比33:1,超声提取时间30min,超声提取温度66℃,浸提次数2次,在此条件下黄酮得率为4.584%.     

荷叶黄酮提取工艺及抗氧性研究

研究荷叶黄酮提取工艺条件,优化荷叶中黄酮提取的工艺参数;研究荷叶黄酮抗氧化作用。以百朋荷叶为原料,采用单因素试验及正交试验设计,从乙醇浓度、提取时间、提取温度、料液比等方面,对提取荷叶黄酮工艺进行优化;并研究荷叶黄酮对羟基自由基和超氧阴离子自由基的清除作用。结果表明:乙醇浸提荷叶黄酮的最佳工艺参数为乙醇浓度为60%、浸提温度70℃、浸提时间1小时、浸提固液比l:60;荷叶黄酮对羟自由基、超氧自由基均有明显的清除作用,且最高清除率分别为55%,45%;荷叶黄酮对油脂有一定的抗氧化性。结论:在优化工艺参数下荷叶中黄酮的提取率为130.83mg/g;荷叶黄酮有一定的抗氧化作用。     

谷精草黄酮类化合物的提取工艺研究

以乙醇为浸提溶剂,从谷精草中提取黄酮类化合物,通过单因素实验和正交实验,考察乙醇浓度、料液比、浸提时间、浸提温度对谷精草黄酮提取率的影响.结果表明,各因素的影响程度依次为:乙醇浓度>浸提时间>浸提温度>料液比;提取的最佳工艺条件为:60%乙醇,料液比1:25,提取时间3h,浸提温度70℃,在此条件下,谷精草黄酮提取率为4.95%.     

谷精草黄酮类化合物的提取工艺研究

以乙醇为浸提溶剂,从谷精草中提取黄酮类化合物,通过单因素实验和正交实验,考察乙醇浓度、料液比、浸提时间、浸提温度对谷精草黄酮提取率的影响。结果表明,各因素的影响程度依次为:乙醇浓度>浸提时间>浸提温度>料液比;提取的最佳工艺条件为:60%乙醇,料液比1:25,提取时间3h,浸提温度70℃,在此条件下,谷精草黄酮提取率为4.95%。      

微波协同萃取及纯化荷叶黄酮的初步研究

本文研究了无水乙醇、乙醇水溶液及乙醇水溶液结合微波照射浸提荷叶黄酮和采用大孔吸附树脂分离纯化荷叶黄酮提取液.实验结果表明:以60%乙醇水溶液作提取剂,固液比1:30、微波照射1.5min、浸提2.5h,荷叶黄酮浸出最多;荷叶黄酮浓度≤25g/l,提取液在4.7BV/h流速下过大孔吸附树脂柱,再用4.5BV/h流速的丙酮洗脱,荷叶黄酮得到较好分离纯化.     

枸杞中黄酮类化合物的提取研究

以乙醇为浸提溶剂从枸杞中提取黄酮类化合物,研究了乙醇浓度、浸提时间、浸提温度及料液比等因素对提取效果的影响.经研究,确定了枸杞中黄酮类化合物的最佳提取条件为:浸提温度70℃,浸提时间2.5 h,料液比1:16,乙醇浓度75%,此条件下黄酮提取率可达0.946%.     

枣渣中黄酮和多糖连续提取工艺研究

应用微波-超声波辅助乙醇法和水提法分别提取枣渣总黄酮和多糖。实验结果表明:枣渣黄酮提取的较优条件为:提取温度65℃、超声提取时间30min、固液比1∶20、乙醇浓度70%,在此工艺条件下黄酮含量为1.50%。枣渣多糖最佳提取工艺为:浸提温度90℃,浸提时间3h,固液比1∶20,粗多糖提取率2.17%,多糖含量达63.64%。     

枣渣中黄酮和多糖连续提取工艺研究

应用微波-超声波辅助乙醇法和水提法分别提取枣渣总黄酮和多糖。实验结果表明:枣渣黄酮提取的较优条件为:提取温度65℃、超声提取时间30min、固液比1∶20、乙醇浓度70%,在此工艺条件下黄酮含量为1.50%。枣渣多糖最佳提取工艺为:浸提温度90℃,浸提时间3h,固液比1∶20,粗多糖提取率2.17%,多糖含量达63.64%。      

荷叶黄酮的提取工艺及其数学模型研究

以荷叶黄酮提取率为指标,采用三元二次回归正交旋转组合试验法优选荷叶黄酮的提取工艺。经过仿真寻优,得出提取荷叶黄酮三个因素的最佳范围为:浸提温度71～74℃、浸提时间1.6～1.9h、料液比1:39～1:44(W/V)。并研究了各因素的交互作用效应,为荷叶黄酮的提取提供了技术依据。     

金花葵花中总黄酮提取工艺的研究

研究金花葵花中总黄酮的最佳提取工艺。通过单因素试验确定影响金花葵花黄酮浸提的因素及水平,采用正交试验设计,确定乙醇浸提金花葵花黄酮的最佳工艺条件为:乙醇浓度60%、温度90℃、时间4h、固液比1∶35(g/mL)。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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