新疆红枣果实不同部位总酚的含量测定

系统地研究新疆红枣果实不同部位总酚含量的最佳提取和测定方法,为进一步开发利用红枣资源提供有效的测试手段。以没食子酸为标准对照品,研究Folin-Ciocalteu比色法测定新疆红枣果肉和果核的中总酚含量的最适宜条件;以总酚含量为指标,通过L_9(3~4)正交试验考察甲醇浓度、料液比、提取时间和提取次数对总酚提取工艺的影响,确定红枣总酚供试品溶液的提取方法。红枣提取液在Folin-Ciocalteu试剂1.5 mL、25%Na_2CO_3溶液2 mL、反应温度30℃、反应时间60 min的条件下,测定其760 nm处的吸光值,没食子酸浓度在0~100μg/mL范围内与吸光度呈良好线性关系(R~2=0.998 8);红枣总酚的最佳提取工艺为50%的甲醇,料液比1∶10(g/mL),提取时间30 min,提取次数2次。加样回收率为98.79%,RSD为1.71%。该提取和测定方法适合于红枣果实总酚含量的测定,利用该方法提取和测定同一产地12个不同品种红枣果核中的总酚含量均明显低于果肉,果肉总酚含量约为果核总酚含量的6倍。     

响应曲面法优化大蒜中总酚提取工艺及其抗氧化活性测定

采用响应曲面法对料液比、提取时间、不同体积分数酸化甲醇提取剂3个因素进行优化,以料液比、提取时间、不同体积分数酸化甲醇提取剂为自变量,总酚提取量为响应值,利用Box-Behnken设计原理和响应曲面法,研究各自变量及其交互作用对总酚提取的影响,模拟求得二次多项回归方程的预测模型,并确定料液比1:14(g/mL)、提取时间31min、80%酸化甲醇为提取剂是最佳的提取条件。在此条件下,总酚提取量为0.67mg GAE/g,模型预测值偏差为6.9%,证明所选工艺条件为最佳工艺条件。同时,用5种方法对其抗氧化活性进行测定,结果表明大蒜具有良好的抗氧化活性。     

响应面设计法优化不同基源贝母中总生物碱的提取工艺

为获得贝母总生物碱的最佳提取工艺参数,以川贝母作为工艺参数研究对象,运用响应面试验设计探讨以氯仿和甲醇体积比、液料比、提取时间作为提取工艺考察因素,以总生物碱为考察指标,用比色法测定不同基源贝母中总生物碱的含量,优化出贝母的最佳提取工艺,并比较不同基源贝母在该最佳工艺条件下总碱的含量差异。结果贝母总生物碱的最佳提取工艺参数为:氯仿:甲醇4.2:1(V/V)、液料比30:1、提取4h,此条件下,四川松潘川贝母的总生物碱含量2.84mg/g。不同基源贝母中,湖北贝母总生物碱的含量最高,达5.379mg/g。本方法结果可靠、操作简便,优化后的最佳提取条件适合贝母总碱的批量提取。     

荸荠皮酚类物质超声波辅助提取工艺优化

采用超声波辅助提取荸荠皮中的酚类物质,考察溶剂种类、料液比、提取温度、超声功率及超声时间对酚类物质提取率的影响。在单因素试验的基础上,确定最佳提取溶剂,并利用响应面法优化工艺条件。结果表明,荸荠皮总酚的最佳提取工艺条件为:甲醇提取,料液比1:15 (g/mL),提取温度55℃,超声功率270 W,超声时间55 min,该条件下总酚含量的最大响应值为4. 42 mg/g;荸荠皮总黄酮最佳提取工艺条件为:甲醇提取,料液比1:20 (g/mL),提取温度60℃,超声功率240 W,超声时间55 min,该条件下总黄酮含量的最大响应值为15. 20 mg/g。     

超声波提取苦菜叶、根中总多酚的工艺研究

以苦菜叶、根为原料,采用超声波辅助乙醇提取总多酚,福林-酚比色法在765 nm波长处测定总多酚的含量。通过单因素试验,正交试验确定最佳提取工艺。单因素试验表明:在提取温度为50℃、提取时间为1.5 h、料液比为1∶15(g/mL)、乙醇体积分数为50%时,苦菜叶、根中总多酚得率都达到最高。提取苦菜叶中总多酚的最佳条件为:提取温度为50℃、提取时间为2.0 h、料液比为1∶20(g/mL)、乙醇浓度为50%。提取苦菜根中总多酚的最佳条件为:超声波功率400 W、提取温度为40℃、提取时间为1.5 h、料液比为1∶15(g/mL)、乙醇体积分数为50%。     

宁夏产区不同品种枸杞中总酚含量分析

借助超声波辅助提取,采用福林酚法对枸杞中总酚含量进行测定。通过优化料液比、提取溶液浓度、提取时间,确定枸杞中总酚提取的最佳条件,即70%乙醇、料液比1∶30(g/mL),提取时间为90 min。同时分析宁夏4个产区4个品种枸杞中总酚含量。结果表明:枸杞中总酚含量在4.53 mg/g^16.07 mg/g之间,其中夏果总酚含量在4.53 mg/g^14.57 mg/g,秋果总酚含量在11.60 mg/g^16.07 mg/g,秋果中总酚含量明显高于夏果,是夏果的1.1~2.6倍。同一品种在不同产区总酚含量存在显著差异。     

燕麦中多酚类物质提取条件的研究

以燕麦为原料,采用酒石酸铁比色法测定多酚含量,研究燕麦多酚的提取条件.通过试验对影响燕麦中多酚提取效果的各因素进行研究,结果表明:提取效果最好的试剂为甲醇,燕麦总多酚提取的最佳工艺条件为:甲醇浓度为85%(体积分数),提取温度80℃,提取时间15min,料液比1:7(g/mL).     

不同品系猴头菇子实体中总酚含量测定

该文以猴头菇子实体为原料,采用超声波辅助提取法优化猴头菇总酚提取工艺条件。采用Folin-Ciocalteu比色法测定总酚的含量,没食子酸为标准品,以猴头菇子实体中总酚的含量为评价指标,分别对提取溶剂、提取时间和料液比进行优化,建立了猴头菇子实体中总酚的含量测定方法,得到最佳料液比1∶40(g/m L),纯水提取,提取时间60 min,总酚含量在0~14μg时与吸光度呈良好的线性关系,其回归方程Y=0.037 3X+0.003 7,r≥0.999,平均加样回收率为101.41%,RSD为1.20%。同时,将该方法在最适条件下测定了10个不同品系猴头菇子实体中总酚的含量,不同品系猴头菇子实体中总酚的含量在2.20 mg/g~4.77 mg/g之间。结果表明,该方法简单、快速、重复性好,可用于猴头菇子实体的总酚含量测定方法。     

响应面试验优化超声波辅助提取圆叶葡萄鞣花酸和总酚工艺

以圆叶葡萄Noble皮和籽为原料,使用丙酮提取溶剂（丙酮-水-盐酸体积比70∶29∶1）,采用超声波辅助提取圆叶葡萄中以鞣花酸为主的多酚类化合物。在单因素试验的基础上,利用响应面试验优化圆叶葡萄皮中鞣花酸和总酚提取工艺,建立数学回归模型,并分析双因素间的交互作用。结果表明,影响圆叶葡萄皮中鞣花酸和总酚含量的显著因素为料液比、提取时间和超声功率,得到的最佳提取工艺条件为料液比1∶30（g/mL）、提取时间28 min、超声功率616 W,此条件下鞣花酸和总酚含量分别为616.21 μg/g和15.06 mg/g（以没食子酸当量计,鲜质量）。用响应面试验对圆叶葡萄中鞣花酸和总酚提取进行优化,可得到最佳工艺条件,验证结果与理论预测拟合度高,可为实际生产提供理论依据。     

菊苣中菊苣酸提取工艺优化

以荷兰菊苣为材料,采用高效液相色谱法测定菊苣酸的含量,建立菊苣酸提取工艺优化方法。通过单因素试验分析回流温度、甲醇体积分数、回流时间及料液比4个主要因素对菊苣酸提取量的影响,在单因素试验基础上采用L9(34)正交试验进一步优化菊苣中菊苣酸提取工艺条件。结果表明:菊苣中菊苣酸的最佳提取工艺为回流温度60℃、70%甲醇、料液比1:60(g/mL)、回流1h。在此条件下菊苣中菊苣酸提取量为8.808mg/g(干质量)。     

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