不同地区野山茶中微量元素的浸出率研究

用干法和沸水分别制备红河州4个县市的野山茶样品,并通过火焰原子吸收法测定其中的Mn、Cd、Cr、Cu等微量元素,RSD值为0.07%～1.69%,回收率在98.7%～116.4%之间。从实验结果计算获得测定的微量元素的浸出率,并对比两种不同浸泡方式的浸出率,浸出率在0～37.44%之间变化;除未检测出的元素外,Fe的浸出率是最低的,通过分析得出在野山茶以及茶水中含有对人体有益的Mn、Zn等微量元素。茶水中不含有Pb、Cd等有害元素,是一种安全的天然饮品。     

红河州野山茶茶水中微量元素比较研究

用泡茶的方式和恒温浸泡方式分别制备了红河州三个县市的野山茶茶水,并通过火焰原子吸收法测定了其中的Mn、Cd、Cr、Cu等微量元素,实验的RSD值为0.07%/～1.69%,回收率在98.7%～116.4%之间,实验方法简单易操作,实验结果准确可靠.从实验结果得出,三个县市野山茶茶水中均未检测出Pb、Cd、Cr、SC这四个元素;并且第一次浸泡茶水中微量元素含量明显高于第二、第三次;说明野山茶作为饮品使用是较为安全的.     

野山茶抗氧化活性研究及微量元素测定

采用不同溶剂、不同条件,从唇形科香薷属植物野山茶的全植株中提取抗氧化活性成分,并通过测定提取浸膏的消除自由基的能力,评价提取物的抗氧化能力。实验表明乙醇和丙酮做溶剂的提取物具有较强的抗氧化能力;通过瓦里安原子吸收光谱仪,在同一溶液中连续测定野山茶中部分微量元素。     

不同产地野山茶三维荧光特性研究

测定了红河州不同地区野山茶的吸收光谱和三维荧光光谱。吸收光谱表明,五个产地的野山茶茶汤均在400nm以下有强吸收,蒙自野山茶的吸收光谱峰主要为235、282、324nm,而其余四地野山茶吸收峰在242、290、350nm附近。荧光光谱表明,各地茶汤均在400～500nm之间出现3个荧光主峰,其1号荧光峰为365～400nm/440～485nm,为黄酮类化合物的荧光峰,且老回龙地区的最强。2号和3号荧光峰也具有明显差异。通过对红河州等地野山茶的研究,利用三维荧光建立了相应的荧光指纹图谱。     

火焰原子吸收光谱法测定薏苡仁中的微量元素

运用火焰原子吸收光谱法直接测定了薏苡仁中Fe、Cu、Zn、Mn、Ca、Mg六种微量元素的含量.用浓硝酸微波消解样品,采用标准曲线法测定.结果所测定的薏苡仁中含有丰富的人体必需微量元素.本方法简单、准确,回收率在99.10%～105.50%之间,相对标准偏差(RSD)小于2.602 8%,结果令人满意.     

大连湾牡蛎中微量元素的分析

采用火焰原子吸收光谱法(FAAS)对牡蛎及其内脏中钠、铜、锌、铁、铅、锶、锰、钙8种微量元素的含量进行连续测定,并时其测定结果作对比分析.同时考察不同消解方法对分析结果的影响,并用加标回收法对比检验方法的可靠性.结果表明:微渡消解法效果较好,相对标准偏差在3.04%以下,回收率为96.89%～104.33%之间.牡蛎中含有丰富的微量元素Na、Cu、Zn、Fe、Sr、Mn、Ca,特别是Cu、Zn含量较高.牡蛎内脏中Na、Cu、Zn、Fe、Mn含量高于完整牡蛎中含量,Sr、Ca含量低于完整牡蛎中含量.牡蛎及其内脏中均未检出Pb.     

原子吸收光谱法测定守宫木中的微量元素

采用火焰原子吸收光谱法连续测定了守宫木中Co、Cr、Cu、Zn、Ni、Fe、Mg、Ca和Pb九种微量元素的含量。其方法的相对标准偏差RSD为0.35%～2.34%,平均回收率在98.5%～110.4%之间。分析结果表明:守宫木中含有人体所需的微量元素,其含量顺序为:Mg>Ca>Fe>Zn>Cu>Ni>Co>Cr,未检测出有害元素Pb,说明守宫木具有较高的食用价值。     

预处理方法对可食牲植物样品中微量元素测定结果的影响

采用干法、湿法和微波消解法处理紫苏样品,以原子吸收分光光度法检测钙、镁、铜、铁、锌和锰6种微量元素的精密度和加标回收率,证实三种预处理方法会显著影响紫苏中微量元素含量的测定结果.与其它两种方法相比,用混酸HNO3-H2O2(6:2)处理紫苏并采用微波消解样品后,各微量元素测定结果的加标回收率较高,加标回收率在99.00%～102.00%之间.相时标准偏差(RSD)低于5%.采用微波消解法对水白菜和山莴苣2种野菜样品以及油麦菜、油菜、韭菜和生菜4种绿叶蔬菜样品进行预处理表明,各微量元素的加标回收率在96.51%～99.87%之间,相对标准偏差(RSD)低于5%,这意味着对可食性植物中的微量元素检测而言,微波消解法预处理样品能够提高测定结果的准确性和重复性.     

FAAS测定侗家奇液酒中13种微量元素

将火焰原子吸收光谱法(FAAS)技术应用于保健酒中微量无机元素的分析,测定了侗家奇液酒中13种微量元素。结果表明,侗家奇液酒含有丰富的微量元素K、Ca、Zn、Fe、Mn、Mg、Mo、Sr、Li、Rb和Se,重金属元素Cu、Pb含量比较低。在选定实验条件下,样品中各元素互不干扰,样品用3 mL/L硝酸稀释后直接进样测定,所测元素回收率为98.1%～103.9%,精密度RSD为0.02%～4.8%。方法简便、快速、安全、可信。     

原子吸收光谱法测定陕西蒲城酥梨中的微量元素

首次报道了陕西蒲城酥梨中微量元素含量的分析方法。采用体积比为4∶1的浓硝酸和高氯酸的混合剂作为消解体系对样品进行硝解,利用原子吸收光谱法测定了蒲城酥梨中的钙、铜、锌、锰、铁、镁等六种微量元素的含量。结果表明:各元素标准曲线相关系数均大于0.9921,相对标准偏差(N=11)在0.82%～2.93%之间,样品的加标回收率在92.68%～105.63%之间。该方法操作简单、快速、准确,适用于蒲城酥梨中微量元素的测定,对蒲城酥梨的合理食用、药用开发、产品研究提供了可靠地理论依据。     

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