液相色谱-质谱联用技术检测婴幼儿乳粉中的丙烯酰胺

建立了婴幼儿乳粉中的丙烯酰胺的高效液相色谱-串联四极杆质谱联用测定方法。样品加水溶解超声提取后,利用乙腈除蛋白,正己烷除脂,使用Hypersil GOLD C18柱(50 mm×4.6 mm(i.d.),1.9μm)分离,经梯度洗脱分离,用电喷雾正离子MRM模式检测,同位素内标定量,可以对婴幼儿配方乳粉中的丙烯酰胺进行定量分析。结果表明:该方法的检出限为5μg/kg,定量限为10μg/kg,线性范围10.0μg/L～200.0μg/L,加标回收率介于86.7%～106.8%之间,相对标准偏差3.07%～9.61%(n=6)。     

气相色谱-串联质谱法测定婴幼儿配方乳粉中的3-氯丙醇酯和缩水甘油酯及其风险评估

建立检测婴幼儿配方乳粉中3-氯丙醇酯和缩水甘油酯的气相色谱-串联质谱法,测定不同市售婴幼儿配方乳粉中3-氯丙醇酯和缩水甘油酯的含量,掌握婴幼儿配方乳粉中酯类污染情况并进行安全风险评估。采用正己烷提取婴幼儿配方乳粉中的3-氯丙醇酯和缩水甘油酯,经过水解、苯基硼酸衍生、气相色谱-串联质谱法测定,内标法定量。结果表明,3-氯丙醇酯和缩水甘油酯总量在0.040 0～4.00μg/m L、3-氯丙醇酯含量在0.020 0～2.00μg/m L的范围内线性良好,相关系数R²>0.999,检出限均为10.0μg/kg,定量限均为25.0μg/kg。在25.0、100、300μg/kg添加水平下,平均回收率在95.0%～98.1%之间。该方法准确率高、回收率好,可用于婴幼儿配方乳粉中的3-氯丙醇酯和缩水甘油酯的检测。150份市售婴幼儿配方乳粉样品中,3-氯丙醇酯检出率为12.7%,含量为ND～52.4μg/kg,平均检出值为29.8μg/kg。缩水甘油酯检出率为6.67%,含量为ND～40.1μg/kg,平均检出值为31.9μg/kg。3-氯丙醇酯的平均暴露水平为0.33～...     

高效液相色谱-串联质谱法测定婴儿配方乳粉中丙烯酰胺的残留量

建立高效液相色谱-串联质谱的测定方法检测婴儿配方乳粉中丙烯酰胺残留量。该方法经水溶解样品后,乙腈去蛋白,正己烷除去脂肪,HLB柱净化,采用电喷雾串联质谱进行定性定量测定。丙烯酰胺浓度为(1～200)ng/m L时线性良好(r0.999),在(10～100)ng/m L水平的加标回收率为90%～110%,相对标准偏差为0.30%～6.20%,检出限为4.0μg/kg。该方法线性良好、准确度高,可满足婴儿配方乳粉中丙烯酰胺残留量测定的需要。     

UPLC-MS/MS测定婴幼儿配方乳粉中双酚A和壬基酚

建立一种测定婴幼儿配方乳粉中双酚A和壬基酚的超高效液相色谱串联质谱准确定性定量方法。向配方乳粉样品中加水溶解,乙腈提取,使用在线捕集技术消除流动相中的本底影响,以甲醇-0.1%氨水溶液作为流动相在C₁₈色谱柱上进行梯度洗脱,用超高效液相色谱仪进行分离后,通过电喷雾负离子模式电离,多反应检测模式进行检测分析,内标法准确定量。结果表明:在1~2000 ng/mL范围内呈良好的线性关系,相关系数大于0.999。本方法BPA和NP检出限均低至0.1 μg/kg,在不同婴幼儿配方乳粉中添加1、10、100 μg/kg三水平加标,测定结果平均回收率在89.5%~102.8%之间,相对标准偏差为1.3%~4.8%,该方法具有较高的灵敏度和准确度。对市售200份婴幼儿配方乳粉进行测定,检出BPA含量为0.1~30.0 μg/kg,检出NP含量为1.1~105 μg/kg,适合婴幼儿配方乳粉中双酚A和壬基酚的定量测定。     

液质联用法测定婴儿乳粉中双酚A和己烯雌酚

建立了婴儿乳粉中双酚A和己烯雌酚残留的高效液相色谱-串联四极杆质谱联用测定方法。样品经碱性乙腈超声提取,以MGⅢ-C18色谱柱（2.1×150 mm,1.8μm）分离,流动相为10 mmol/L乙酸铵水溶液和甲醇（梯度洗脱）,流速0.25 mL/min。采用多反应监测负离子模式,可以同时对婴幼儿配方乳粉中的双酚A和己烯雌酚进行定性和定量测定。方法在1.0μg/L～25.0μg/L范围内呈良好线性,方法的检出限为5μg/kg。在5、25、250μg/kg三个加标水平下,加标回收率为80.6%～102.9%,相对标准偏差为1.29%～8.83%。     

免疫亲和柱净化/色谱技术测定婴幼儿配方乳粉中V_(B12)

建立了婴幼儿配方乳粉中VB12的超高效液相色谱-串联质谱和超高效液相色谱测定方法。样品采用pH=4.0的醋酸钠溶液提取,经免疫亲和柱净化,采用Waters BEH C18色谱柱分离,液相法采用0.03 mol/L的磷酸缓冲盐(pH=3.5)和乙腈为流动相进行等度洗脱,紫外检测器波长为361 nm。质谱法以0.1%的甲酸水和甲醇为流动相进行梯度洗脱,采用电喷雾-正离子模式多反应监测进行定性和定量分析,外标法定量。VB12在10~500μg/L的质量浓度范围内线性关系良好,VB12的检出限均为0.5μg/kg,定量限均为1.5μg/kg,液相方法回收率为90.2%~98.3%,相对标准偏差为1.4%~2.5%,液相色谱-质谱法回收率为89.3%~95.7%,精密度在1.9%~3.1%。该方法简单、灵敏度高、分析时间短、定量准确,适用于婴儿乳粉中VB12的测定。     

LC/MS/MS测定婴幼儿配方乳粉中3种苯扎氯铵同系物

建立液相色谱-串联质谱法测定婴幼儿配方乳粉中3种苯扎氯胺同系物残留的方法。样品经2%乙酸水溶液和乙腈超声辅助提取。采用多反应监测模式对目标化合物进行定性和定量测定。在最优条件下,目标化合物在10μg/kg~500μg/kg范围内有较好的线性关系,检出限和定量限分别为3μg/kg和10μg/kg。方法加标回收率为85.1%~102.1%,相对标准偏差(RSD)为3.05%~8.35%。采用所建立的方法对中国市面上的婴幼儿配方乳粉进行检测,10个检测样品中均有苯扎氯胺存在,浓度范围为73μg/kg~501μg/kg。     

内蒙古地区婴幼儿配方乳粉中高氯酸盐与氯酸盐膳食暴露风险评估

目的 了解内蒙古地区婴幼儿配方乳粉中高氯酸盐和氯酸盐的污染水平，评估婴幼儿高氯酸盐和氯酸盐的膳食摄入风险，为指导内蒙古地区婴幼儿健康膳食提供科学依据。方法 采集内蒙古地区市售各段位的婴幼儿配方乳粉539份，乳粉冲调用水（冲调乳粉时可能使用的饮用水）254份，采用超高效液相色谱-串联质谱（UPLC-MS/MS）法对婴幼儿配方乳粉、乳粉冲调用水中的高氯酸盐和氯酸盐含量进行检测。以2015年中国婴幼儿食品消费量调查数据中内蒙古地区婴幼儿的消费量数据为依据，采用简单分布评估和累积暴露评估方法计算内蒙古地区婴幼儿配方乳粉中高氯酸盐和氯酸盐的膳食摄入风险。结果 婴幼儿配方乳粉中高氯酸盐的总体检出率为92.39%(498/539)，检测值在未检出～89.30μg/kg，平均值为14.45μg/kg，中位数为9.00μg/kg；氯酸盐的总体检出率为73.10%(394/539)，检测值在未检出～1 061.00μg/kg，平均值为93.25μg/kg，中位数为45.50μg/kg。乳粉冲调用水中高氯酸盐的总体检出率为67.32%(171/254)，检测值在未检出～26.59μg/L，平均值为1.25μ...     

液质联用法同时测定婴幼儿配方乳粉中氯酸盐和高氯酸盐残留

建立了婴幼儿配方乳粉中氯酸盐和高氯酸盐残留的高效液相色谱-串联四极杆质谱联用测定方法。样品经水超声溶解,乙腈除蛋白。以PC HILIC色谱柱分离,流动相为浓度50 mmol/L的乙酸铵水溶液和乙腈,流速0.25 mL/min。液相色谱-串联质谱仪测定,基质内标法定量。在该优化条件下,氯酸盐和高氯酸定量限分别为20μg/kg和2.0μg/kg,方法回收率为85.1%～94.7%,相对标准偏差(RSD)为2.38%～9.79%。经测定多种市售婴幼儿配方奶粉,表明该方法操作简单、测定结果准确,可用于婴幼儿配方奶粉中氯酸盐和高氯酸盐残留的同时快速测定。     

液相色谱-串联质谱法测定婴幼儿配方乳粉中六种消毒剂残留

建立了婴幼儿配方乳粉中苯扎溴铵、C12-苯扎氯铵、C14-苯扎氯铵、C16-苯扎氯铵、二癸基二甲基氯化铵和四丁基硫酸氢铵等6种消毒剂的液相色谱-串联质谱测定方法。样品经水超声提取,乙腈除蛋白,液相色谱-串联质谱仪测定,基质外标法定量。结果表明,6种消毒剂的线性范围为0.5～20μg/L,相关系数(r2)均大于0. 99。方法的检出限(LODs,信噪比为3)在0.2μg/kg,定量限(LO?Qs,信噪比为10)在0.5μg/kg。基质中3个加标水平的回收率都在87.3%～104.6%之间,加标含量范围为0.5～5.0μg/kg,相对标准偏差(RSD,n=6)在2.96%～9.87%之间。采用建立的方法对市面上销售的50种婴幼儿配方乳粉中6种消毒剂进行了筛查,达到了预期效果。方法能满足婴幼儿配方乳粉消毒剂残留的检测工作的要求。     

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.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.