牛乳过敏原β-乳球蛋白核酸适配体在食品检测中的应用

食物过敏已成为全球广泛关注的食品安全问题。目前,食物过敏尚无根治疗法,避免摄入含过敏原的食物是患者的最佳选择。牛乳作为八大过敏性食物之一,建立快速灵敏的检测方法对保护牛乳过敏患者至关重要。β-乳球蛋白是牛乳中的主要过敏原,可以作为检测食品中是否含牛乳蛋白的有效标志物。核酸适配体是通过指数富集的配体系统进化技术筛选获得的,能与靶标特异性结合的单链寡核苷酸。作为一种新型识别元件,核酸适配体具有易合成、易修饰、费用低、分子量小、稳定性好、亲和力高等优点,在快速高灵敏检测等方面具有广阔的应用前景。本文简要概述了核酸适配体的筛选流程与筛选方法,重点综述了β-乳球蛋白核酸适配体的筛选及其在检测方面的应用现状,并对核酸适配体技术的未来发展方向进行了展望,以期促进其在过敏原检测等领域的应用。     

基于核酸适配体的生物传感技术在食品安全领域中的研究进展

近年来食品安全事件频发,严重影响了消费者对食品行业的信心.虽然传统的检测技术能对食品中的有害物质进行高选择性和高灵敏度的检测,但是仍需要一种简单、快速、有效、成本低廉的方法用于食品安全领域的快速检测.核酸适配体是一段DNA或者RNA序列,是利用体外筛选技术从核酸分子文库中得到的寡核苷酸片段.具有特异性强、稳定性好和靶分子广等特点,近年来被广泛用于食品安全检测领域.本文综述了近年来核酸适配体在食品安全检测领域的应用,对核酸适配体在食品安全检测领域的问题进行了探讨,并对其在食品安全检测领域的发展前景进行了展望.     

基于功能核酸的食品重金属污染快速检测进展

食品安全与人类健康息息相关。重金属污染已成为食品安全领域的突出问题,为保证食品安全,构建快速、廉价和可推广的食品重金属污染检测方法显得尤为重要。近年来,以功能核酸为基础的生物传感及分析技术引起了广泛关注。核酶和核酸适配体等功能核酸作为一种新型的生物识别分子,可实现对金属离子的特异性识别,在构建高灵敏、高选择性的食品重金属分析检测平台方面具有巨大的应用潜力。本文综述了功能核酸在重金属(铅、汞和镉)污染检测领域的应用进展,重点介绍了由功能核酸构建的荧光传感器和比色传感器,及功能核酸与纳米粒子复合构建的核酸纳米传感器。此外,考虑到食品重金属离子检测所涉及的区域范围广、样品数量多等问题,本文突出了功能核酸与微流控技术及便携检测设备整合的检测平台,为临场的食品重金属污染分析提供思路。     

核酸适配体传感器应用于牛乳检测的研究进展

近些年食品安全问题频发,牛乳质量安全及掺假问题备受关注。核酸适配体传感器是新兴的检测方法,具有特异性强、灵敏度高、操作方便等优点。将核酸适配体传感器用于牛乳检测是将来的一个发展方向。本文主要对近年来应用核酸适配体传感器检测牛乳中致病菌、抗生素、生物毒素、重金属和其他微量有害物质进行综述,并且对这种检测方法目前存在的问题和未来的发展前景进行分析,以期为这种新兴的技术更好地应用于牛乳检测提供参考。     

适配体传感器在有机磷农药残留检测中的应用

有机磷农药在农业生产中因防治病虫害效果好而被广泛使用, 但易在环境和农产品中产生不同程度的残留, 不仅污染环境, 而且威胁食品安全, 因此对其进行快速高效、灵敏精准检测尤为必要。适配体具有易修饰、易合成、性质稳定、特异性强和亲和力高等优势, 适合作为有机磷农药的特异性高效识别工具, 广泛应用于生物传感器检测方法的构建中。本文综述了应用于有机磷农药残留检测的比色适配体传感器、荧光适配体传感器、电化学适配体传感器等进行检测方法, 归纳了所用适配体序列、检测策略及检测特性, 提出了构建适配体传感器应注意的主要问题和发展趋势, 以期为适配体传感检测技术的深入研究提供参考。     

基于信号放大策略的适配体电化学传感器检测真菌毒素研究进展

真菌毒素是真菌分泌的一类次级代谢产物, 是农产品的主要污染物之一, 具有强毒性。人畜误食会导致急性、慢性中毒症状, 严重危害农产品安全, 威胁人类健康。开发快速、超灵敏、高通量、高性价比的传感技术十分重要。适配体是一段单链DNA或RNA, 具有特异性良好、合成简单、易于化学修饰、稳定性高等优势, 且可以与基于核酸的传感及扩增策略相结合, 具有广阔应用前景。电化学传感器因其反应快速、灵敏度高、成本低等优势受到广泛关注。适配体电化学传感器已成为目前检测真菌毒素的有力工具。本文综述了适配体电化学传感器常见的信号传感方式, 主要关注基于核酸和纳米材料的信号放大策略, 以及它们在检测应用中的优势与不足; 最后对该技术的发展趋势进行了展望, 为基于适配体的真菌毒素电化学传感器的深入研究与应用提供参考。     

核酸适配体生物传感器在食品霉菌毒素检测中应用的研究进展

霉菌毒素是由霉菌产生的次级代谢物,是人类健康的主要威胁之一。食品中霉菌毒素的污染已经成为人们热切关注的主要食品安全问题之一,所以开发出用于简便、快速和灵敏检测食品中霉菌毒素的方法显得尤为重要。核酸适配体是在体外筛选,并能特异性识别目标物的单链寡核苷酸序列,因具有易合成、易标记、易修饰、灵敏度高、特异性高、分子量小等优势而广泛应用于蛋白质、霉菌毒素、农兽药等目标物检测的生物传感器。本文主要综述了食品中霉菌毒素的限量和危害,以及核酸适配体生物传感器筛选技术用于食品中霉菌毒素检测的研究进展。     

核酸适配体生物传感技术在食品污染物检测中的应用

核酸适配体生物传感技术是近些年发展起来的一种新的检测技术,具有靶向性强、灵敏度高、价格低廉等优点,被广泛应用于医药工业、生物医学、环境分析、食品分析等领域。其中,在食品分析领域主要体现在农残、重金属、食品添加剂以及生物毒素等检测方面。本文首先介绍了核酸适配体的概念、筛选方法、核酸适配体传感器优点,重点从传感器的设计、传感检测原理、检测性能等方面综述了核酸适配体生物传感器在Pb~(2+)等食品污染物检测中的应用;最后对核酸适配体生物传感器的发展趋势进行了展望。     

核酸适配体技术在食品重金属检测中的应用研究进展

近年来食品中重金属超标对人们健康构成了威胁,所以对食品中重金属检测技术的开发成为了重要研究内容。虽然传统的检测技术对重金属进行了高选择性和高灵敏度的检测,但是仍需要一种简单、快速、有效、成本低廉的方法用于食品安全领域的快速检测。核酸适配体为一段单链DNA或者RNA序列,是经体外筛选技术筛选出的能特异结合蛋白质或其他小分子物质的寡聚核苷酸片段。核酸适配体具有靶分子广、灵敏度高、特异性强、稳定性好等特点,因而被广泛用于食品安全检测领域。本文综述近年来核酸适配体技术对食品中Hg2＋、As3＋、Pb2＋的检测,并对核酸适体技术在食品重金属检测领域的应用前景进行了展望。     

核酸适配体传感器在四环素类抗生素检测中的应用

四环素类抗生素作为一类广谱抗生素被广泛用于控制细菌感染,由于其化学性质相对稳定,超量使用和不当处理均会导致其在土壤、水体、食品中的残留严重,给人类公共健康带来重大威胁。检测四环素类抗生素所采用的方法通常为高效液相色谱法、免疫分析法等,这些方法具有耗时长、操作步骤复杂、成本高等局限性,因而开发敏感、快捷、经济的检测方法尤为重要。核酸适配体作为一种新型生物识别分子,具有亲和力高、稳定性强、制备成本低、特异性强等明显优势,被广泛应用于食品安全、环境监测、生物医药等多个领域,在四环素类抗生素的快速分析中占有重要地位。本文主要综述了用于四环素类抗生素检测的核酸适配体传感器,主要包括荧光、比色、电化学、表面等离子体共振、表面增强拉曼光谱等适配体传感器,并阐述了适配体传感器最新研究进展以及各种方法的优缺点。     

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.     

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.     

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.     

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.     

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.