超高效液相色谱-串联质谱法检测河鲀毒素

目的建立准确、快速检测河鲀毒素(tetrodotoxin,TTX)的超高效液相色谱-串联质谱(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)的分析方法,了解市售烤鱼片、鱿鱼干制品和鱼丸中河鲀毒素污染状况。方法样品经2%乙酸/甲醇溶液超声离心提取后,通过MCX固相萃取柱进行净化处理,采用液相色谱串联质谱法进行检测。结果市售的107份样品中,鱿鱼干制品和鱼丸中没有检出TTX;64份烤鱼片样品中检出16份含有TTX,检出率为25.0%。结论部分烤鱼片中TTX呈阳性,建议生产厂家严把原料关,监管部门应加强对市售烤鱼片标签标识的监管。     

鲀毒鱼毒素检测及物种鉴定技术研究进展

鲀毒鱼引起的河鲀毒素(tetrodotoxin,TTX)中毒是中国沿海地区食物中毒致死的主要原因之一.河鲀毒素中毒发病迅速,至今尚无特效药,因此,通过检测TTX含量或鉴定携带TTX的物种可以更好地进行TTX中毒的风险分析、管理和控制.本文综述了鲀毒鱼TTX的检测技术以及鲀毒鱼物种鉴定的方法,以期能预警并减少鲀毒鱼引起的...     

免疫亲和柱净化-亲水液相色谱-串联质谱法测定水产食品中河鲀毒素

目的本文采用免疫亲和柱选择性吸附样品溶液中的河鲀毒素,建立了测定水产食品中河鲀毒素(TTX)的亲水液相色谱-串联质谱分析方法。方法样品以含1%乙酸的甲醇溶液提取,磷酸盐缓冲溶液稀释,再经免疫亲和柱富集和净化后进样分析。目标物以TSK-gel Amide-80亲水色谱柱(150 mm×2.0 mm,5μm)分离,乙腈-0.1%甲酸水溶液(含5 mmol/L乙酸铵)梯度洗脱,采用电喷雾离子源,选择反应监测(SRM)正离子模式检测,溶剂标准曲线校正,外标法定量。结果 TTX在1~1 000μg/L范围内线性良好,方法的检出限为1μg/kg,定量限为3μg/kg,在3~300μg/kg范围内加标回收率为73.6%~95.2%,相对标准偏差(RSD)为5.37%~10.7%。结论该方法可有效消除复杂基质样品中普遍存在的基质抑制效应,操作简便,色谱保留时间稳定,灵敏度高,准确度和重复性好,适用于烤鱼片、风味鱼干等水产食品中河鲀毒素的测定。     

河鲀中河鲀毒素检测研究进展

河鲀毒素(tetrodotoxin,TTX)是一种毒性极强的天然小分子生物碱,无特效解毒剂,中毒潜伏期短,在水产品质量安全领域受到极大关注。本文总结了河鲀毒素的毒性、相关法规、化学性质和反应特点,并对河鲀毒素检测过程中样品前处理以及检测方法进行了总结,并详细综述了河鲀毒素常用的生物检测法、液相色谱荧光检测法、气相色谱串联质谱法、液相色谱串联质谱检测法和免疫及电化学检测方法应用情况,尤其对免疫检测与电化学技术结合的方法进行了分类分析。最后,本文分析了免疫分析过程中竞争型和非竞争型免疫的区别与优缺点,并对新型电化学免疫快速检测的方法开发进行了展望,以期为检测TTX等小分子化合物的新型检测技术的开发提供参考。     

COI及cytb基因对河鲀鱼鱼种鉴定的适用性研究

目的建立河鲀鱼DNA条形码鉴定方法,探讨细胞色素氧化酶亚基I(COI)及细胞色素b(cytb)基因对我国常见东方鲀属、兔头鲀属河鲀鱼鱼种鉴定的适用性。方法野捕河鲀鱼经形态学鉴定后,钓取COI及cytb基因序列并测序。从Gen Bank下载已有河鲀鱼参考序列,分别构建COI及cytb基因分子进化树,确定样品种属并与形态学鉴定比对。应用所建方法对中毒样品进行河鲀成分鉴定。结果 COI和cytb基因分子进化树将57份样品聚类到东方鲀属和兔头鲀属的9个鱼种,除棕斑兔头鲀和暗鳍兔头鲀(COI进化树)、暗纹东方鲀和晕环东方鲀(cytb进化树)外,2种条形码均能对其余鱼种进行有效区分。中毒样品经鉴定均含有月兔头鲀。结论所建立的DNA条形码方法可有效鉴定河鲀鱼鱼种,弥补形态学鉴定的缺陷。     

应用DNA条形码技术鉴定烤鱼片、鱼干中河鲀鱼鱼种

应用DNA条形码技术对北京和厦门市市售烤鱼片、鱼干中河鲀鱼成分进行鉴定。方法 以烤鱼片、鱼干中提取基因组DNA为模板,利用针对河鲀鱼细胞色素氧化酶亚基Ⅰ(COⅠ)基因的特异性引物进行PCR扩增,将扩增产物克隆并测定线粒体COⅠ基因序列。将测序结果与GenBank中已有河鲀鱼的DNA序列进行BLAST比对,并且构建分子进化树。结果 本研究27份样品中有15份能扩增出特异性条带。通过BLAST比对和进化树分析,将15份样品归属到不同的河鲀鱼鱼种中。结论 北京和厦门市市售烤鱼片和鱼干中存在混入河鲀鱼的现象,应加强监管和规范产品的加工程序以避免中毒事件发生。     

液相色谱串联质谱法测定河豚毒素标准品

河鲀毒素(TTX)是河鲀鱼类体内合成的一种有毒的生物碱,是目前人类发现的自然界中毒性最大的神经毒素之一。本文在3家公司的质谱仪上分别建立了测定河豚毒素标准品的仪器方法,可为用不同公司生产的仪器测定河豚毒素提供参考。     

不同基质条件下食品防腐剂对冷藏河鲀鱼片腐败菌的抑菌差异

为筛选冷藏红鳍东方鲀鱼片的复配保鲜剂,本文通过稀释平板法分离筛选冷藏河鲀鱼片感官腐败末期的腐败菌,利用16s r DNA序列进行菌株鉴定,测定接种腐败菌后冷藏河鲀鱼片TVBN和TMA值衡量各腐败菌致腐能力;采用酶标比浊法测定山梨酸钾、尼泊金乙酯和乳酸链球菌素(Nisin)在培养基和河鲀鱼肉汁2种基质条件下对腐败菌的抑菌效果。结果表明:在冷藏红鳍东方鲀鱼片腐败末期分离获得4株腐败菌,分别为荧光假单胞菌、莓实假单胞菌、热杀索丝菌和乡间布丘氏菌,均有显著的致腐能力;随山梨酸钾溶液浓度的降低对腐败菌的抑菌活性显著下降,在鱼肉汁中的抑菌效果显著优于液体培养基条件;尼泊金乙酯溶液在不同基质下均能高效抑制4株腐败菌的生长繁殖;Nisin溶液仅对热杀索丝菌具有显著的抑菌效果,且抑菌活性易受基质的影响。不同防腐剂对冷藏河鲀鱼片腐败菌的抑菌活性排序为尼泊金乙酯山梨酸钾Nisin,尼泊金乙酯和山梨酸钾可成为冷藏河鲀鱼片的复配保鲜剂。     

高效液相色谱-串联四级杆质谱法测定鱼体中河豚毒素

目的建立高效液相色谱-串联四级杆质谱联用仪多反应监测技术(MRM)测定鱼体中的河豚毒素(TTX)含量的方法。方法海鱼样品用80%酸化甲醇水溶液(含0.1%乙酸)超声提取,二氯甲烷脱脂净化,超滤管离心,取滤液过膜后进行分析。目标物TTX以p H=3.5的乙腈-0.06%甲酸铵溶液(65∶35,V/V)为流动相,经HILIC色谱柱(100 mm×2.1 mm,3μm)等梯度洗脱分离,采用电喷雾离子源,选择质谱多反应监测正离子模式,以保留时间和河豚毒素的二级质谱特征碎片离子予以双定性确证,基质标准曲线校正,外标法定量。结果河豚毒素与杂质能良好分离,在0.10~2.0 mg/kg范围内线性关系良好(r=0.997),方法检出限为0.012 mg/kg,定量限为0.041 mg/kg,加标回收率为75.7%~108.1%,相对标准偏差为1.4%~5.1%。应用该方法对20份实际样品进行检测,均未检出TTX。结论本方法准确、快捷、简便,可应用于食物中毒因子识别与鉴定。     

河鲀毒素生物传感器的研究

基于河鲀毒素(TTX)对细胞膜Na+通道的阻断作用,建立一种检测TTX的简易组织生物传感器。组织生物传感器由pNa电极、青蛙膀胱膜、电位计等构成。在pNa电极顶端用两层醋酸纤维薄膜包裹,中间夹入青蛙膀胱膜,构成感受器。将电极插入pNa=4的NaCl溶液中,使电极输出信号趋于稳定。将TTX被测液注入感受器系统,测定感受器输出量的抑制值。每次测定只需5min。最低检出限为0.002MU/ml(3.56×10-3μg/ml)。用0.003%Na3N保存,可连续使用250h。以生物传感器和小鼠生物试验法比较,建立了工作曲线,便于在餐饮企业对原料鱼进行检测和应用。     

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.     

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.     

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.     

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.     

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.