火焰原子吸收法测定苦荞中微量元素

建立火焰原子吸收光谱法测定苦荞中微量元素锌、钾、铁、锰、钙、铅、铬、铜、锶的含量。用HNO3+HClO4对样品进行湿法消解,采用氘灯背景校正,在同一体系中连续测定不同元素。在选定的最佳分析条件下测定了苦荞中锌、钾、铁、锰、钙、锶、铅、铬、铜的含量,回收率为94%~106%,相对标准偏差小于5%。     

原子吸收光谱法测定仙草产品中7种元素含量

建立微波消解-原子吸收光谱法测定仙草及其产品中铅、镉、铬、铜、铁、锌、锰7种微量元素的含量。样品经微波消解,无火焰法测定铅、镉、铬元素、火焰法测定铜、铁、锌、锰元素含量。所测元素标准曲线相关系数均≥0.998,回收率在85.9%~110.0%间,RSD均5%。本研究建立的方法简便、准确、成本低廉,可用于仙草及其产品中铅、镉等7种元素含量的检测。     

大连地区12种常见海产贝类微量元素的测定与分析

测定大连地区海产贝类中微量元素的含量并对其进行分析.利用火焰原子吸收光谱法(PAAS)对大连市面所售的12种常见海产贝类中的锌、铁、铜、锰等微量元素进行了含量测定,并用加标回收法检验了该方法的可靠性.结果:1)海产贝类中富含锰、铁、锌、铜.2)同种贝类不同组织的微量元素含量存在显著差异.本实验方法简便、快速,易于操作,准确度高,并为人们通过食用贝类补充微量元素提供了理论依据.     

葡萄园土壤中铜、铁、锌、锰四种金属元素的分析与研究

采用湿法消解处理样品,火焰原子吸收光谱法检测河北昌黎葡萄酒产区5 个葡萄园土壤中的铜、铁、锌、锰4 种金属元素。并对比研究3 种葡萄、葡萄酒与葡萄园土壤中铜、铁、锌、锰4 种金属元素含量的关系。对不同葡萄园和同一葡萄园种植不同品种葡萄,其土壤中金属元素含量进行差异性分析。结果显示：葡萄园地理位置和微环境及所栽培的葡萄品种、树龄和架势不同,土壤中4 种金属元素含量不同,差异性显著。铁、锌、锰3 种元素在土壤中的含量与葡萄中的含量有一定关系。赤霞珠、美乐和西拉3 种葡萄的土壤中铜、铁、锌的含量与葡萄及其葡萄酒中相对含量规律相同,而锰不同。     

产地、物种及加工工艺对油茶籽油中的微量元素及重金属含量的影响

以贵州不同产地及物种的油茶籽为原料,分别采用烘制和炒制对其进行预处理后压榨制油,并对油茶饼进行二次压榨制油,对不同预处理及不同压榨阶段油茶籽油的微量元素及重金属含量进行分析。结果表明：不同产地和物种的油茶籽油的微量元素及重金属含量存在不同程度的差异,形成不同品质特征的油茶籽油;与烘制预处理相比,炒制可以显著提升油茶籽油中锰、铁、铜含量（P＜0.05）,但同时增加油茶籽油中的重金属含量;不同压榨阶段油茶籽油的微量元素含量具有显著差异（P＜0.05）,二次压榨可使油茶籽油中的锰和铁含量显著增加（P＜0.05）,且蒸制处理可以提升二榨油茶籽油中的微量元素含量;相关性分析显示,不同微量元素及重金属含量之间具有不同程度的相关性,锰和锌、铅有极显著的负相关性,锌和铅有极显著的正相关性,镍和铬有极显著的正相关性。     

铜、铁、锌、锰添加水平对蛋青鸡生长性能及养分利用的影响

525只1日龄罗曼褐壳蛋鸡随机分为5处理,每处理7重复,每重复15只鸡。所有处理使用一种基础日粮,统一添加碘和硒。铜、铁、锌、锰四种微量元素添加方案如下,A组不额外添加;B组按50%NRC标准直接添加;C组和D组将日粮铜、铁、锌、锰总量补齐到2倍和3倍NRC水平;E组以基础日粮铁含量与NRC标准比值为基准,将其余微量元素校正到同样倍数。铜、铁、锌、锰添加形式均为硫酸盐。结果表明,1~18周龄生长蛋鸡典型基础日粮中添加铜、铁、锌、锰不影响采食量(P>0.05)、期末体重和能量表观代谢率(P>0.05),过量添加降低日增重和饲料转化率(P<0.05),但提高蛋白质表观代谢率(P<0.05)。随日粮微量元素水平增加,排泄物铜、锌、锰含量线性增加(P<0.05),铜、锌、锰表观代谢率呈先增加后降低二次曲线变化(P<0.05)。西北地区典型蛋青鸡基础日粮中铜、铁,锌、锰已满足需要,无需额外添加。     

毕节地区初烤烟叶中微量元素含量分布特征研究

对贵州毕节地区各县(市)不同植烟区域275个初烤烟叶中、微量元素进行了分析。结果表明,毕节地区烟叶中、微量元素含量较为适宜,铜、锌、锰、铁、镁、钙的平均含量分别为7.89 mg/kg、40.51 mg/kg、225.96 mg/kg、444.72 mg/kg、0.46%、2.95%;铜、锌、钙含量处于适中水平,锰、铁含量处于较高或高水平,镁含量处于较低水平。锰含量高的烟样主要分布在毕节、大方、黔西、金沙和纳雍;钙含量高的烟样主要分布在金沙、黔西和织金;全区烟叶镁含量普遍偏低。中微量元素在烟叶的不同部位上分布较有规律,锰、铁、钙元素的含量随烟叶部位的上升而下降,而铜和锌的含量随烟叶部位的上升而上升。     

微量元素对籽粒中大豆异黄酮积累的影响

对两个大豆品种（高异黄酮品种中豆27和普通品种九农20）进行盆栽试验,施用七种微量元素（镁、硼、锰、锌、铜、铁和钼）,利用高效液相色谱法（HPLC）检测大豆籽粒的异黄酮含量。结果显示,不同微量元素对大豆籽粒的异黄酮含量影响差异显著,其中五种微量元素（镁、硼、锰、铜和铁）使大豆异黄酮含量增高,但到一定浓度时,则含量下降;锌元素对大豆异黄酮含量的影响随着微量元素含量提高呈下降趋势;钼元素对大豆异黄酮含量的影响随着微量元素含量提高呈增高趋势。微量元素的含量对异黄酮含量的积累影响很大,镁、硼、锰、铜和铁五种微量元素的含量在0.5mmol/L～1.0mmol/L之间异黄酮含量最高。     

宁夏盐池县7种小杂粮中微量元素锌、锰、铜、铁的初步调查

小杂粮是我国医食同源的保健食品原料作物,但不同种类小杂粮微量元素含量的报道很少.该文以火焰原子吸收法测定了荞麦、小米、黄米、豌豆、绿豆、扁豆、红豆7种小杂粮中锌、锰、铜、铁的含量,结果表明,7种小杂粮中锌、锰、铜、铁4种微量元素含量都比较高.虽然不同种类元素之间的含量稍有差异,但是这些元素在药用机理方面有不可替代的作用.该文为开发小杂粮保健食品和深加工研究提供理论基础.     

忍冬茶及其加工过程中氨基酸和微量元素分析

目的:考察忍冬茶及其加工过程中氨基酸、微量元素含量的变化情况。方法:采用L-8800型全自动氨基酸分析仪分析忍冬茶及其加工过程中氨基酸种类及其含量的变化情况;采用火焰原子吸收光谱法测定铜、锌、铁等9种微量元素的含量。结果:忍冬茶中含有17种氨基酸且含量丰富,加工前后17种氨基酸的种类没有变化但含量都有所增加;加工后微量元素锌、铁、锰的含量增加,铜、铅、铬、镍、砷的含量降低。忍冬茶经过冲泡后有害金属元素铅、镉、镍、砷含量均符合GB2762—2005《食品中污染物限量》中规定的标准。结论:忍冬茶的加工过程增加了氨基酸和多种有益微量元素的含量,降低了多种有害金属元素的含量,有害金属元素含量均符合GB2762—2005《食品中污染物限量》中规定的标准,表明忍冬茶加工工艺可行,饮用安全。     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.