食品中酪蛋白过敏原检测方法的比较

目的 比较市场上销售的三种检测牛奶中酪蛋白ELISA试剂盒效果。方法 以脱脂奶粉、酪蛋白做作阳性添加成分, 对三个品牌的ELISA试剂盒从回收率、精密度、特异性等方面进行比较。结果 ELISA试剂盒可以对多种食品进行酪蛋白含量检测, 回收率、精密度等各项检测性能指标均可满足相关检测低限要求。结论 ELISA检测试剂盒无需大型分析仪器、操作简便快捷、适用于大量样品快速初筛和各种基层实验室食品品质监控。     

食品加工对过敏原活性的影响

近年来, 食物过敏性疾病的发病率明显上升, 已成为影响人类健康最常见的全球性疾病之一。本文对食品加工中常用的几种方法对特定食品过敏原活性的影响进行了综述, 这些加工方法包括热处理、高压处理、研磨、辐照、碱水解、梅拉德反应、酶解、微生物发酵和基因工程等, 并对存在的问题进行了分析。     

加工食品中花生蛋白夹心酶联免疫吸附测定的前处理方法探究与改进

目的 构建一种可配合花生蛋白夹心酶联免疫吸附测定(enzyme-linked immunosorbent assay, ELISA)试剂盒实现对于加工食品中花生成分可靠检测的高质量样品前处理方法。方法 对9种不同pH的提取缓冲液提取未处理、湿热处理、干热处理花生蛋白效果进行比较分析以确定最优提取缓冲液类型。而后, 将吐温-20、二硫苏糖醇(dithiothreitol, DTT)、十二烷基硫酸钠(sodium dodecyl sulfate, SDS)以单独或组合添加的方式加入上一步获得的最优提取缓冲液中, 提取3组花生蛋白, 并对提取效果与夹心ELISA试剂盒检测花生蛋白回收率进行比较分析以确定最优添加剂配方。结果 最终确定添加0.2% SDS和0.1%吐温-20的碳酸盐缓冲液(50 mmol/L, pH 9.6)为最优提取缓冲液。向碳酸盐缓冲液中加入SDS、吐温-20较好地提升了花生蛋白的提取率和回收率, 将湿热处理花生蛋白回收率提高了2倍以上。结论 本研究实现了对商业加工食品中花生成分的可靠检测, 为推动过敏原信息在食品标签的准确标注提供了技术支撑, 也为相关研究提供了参考。     

食品中β-乳球蛋白过敏原检测方法的比较

目的 比较市场上销售的两种检测牛奶中β-乳球蛋白ELISA试剂盒效果。方法 以脱脂奶粉、β-乳球蛋白作阳性添加成分, 对两个品牌的ELISA试剂盒从回收率、精密度、特异性等方面进行比较。结果 ELISA试剂盒可以对多种食品进行β-乳球蛋白含量检测, 回收率、精密度等各项检测性能指标均可满足相关检测低限要求。结论 ELISA检测试剂盒无需大型分析仪器、操作简便快捷、适用于大量样品快速初筛和各种基层实验室食品品质监控。     

ELISA法快速检测食品中重金属含量的研究进展

重金属超标会对人体健康产生极大危害,世界各国日渐重视食品中重金属的限量标准,同时对重金属分析检测方法的研究也越来越多。传统的重金属检测方法比较成熟,灵敏度高,但操作繁琐、费用高昂、依赖大型仪器设备以及需要专业技术人员操作等。酶联免疫(enzyme-linked immune sorbent assay,ELISA)法是一种特异性强、灵敏度高的检测方法,并能用于现场快速检测,故得以迅速发展。ELISA法检测重金属主要包括四大关键步骤:样品前处理、人工抗原的合成、特异性抗体的制备、ELISA方法的选择。该文主要综述了ELISA法在检测重金属方面的最新研究成果,并对该检测技术的研究方向进行了展望。     

食品中重金属检测的前处理方法的探究

随着工农业的快速发展,人们收入水平的不断提高,对生活质量有了更高的要求,其中食品质量是影响生活质量的重要因素,污染所导致的食品安全问题得到社会的广泛关注.本文针对食品中重金属检测的前处理方法进行了探究,阐述了检测重金属样品的预处理方法:微波消解法、湿消解法、干法灰化法.     

ELISA法检测大米、食用油中黄曲霉毒素B1前处理方法的研究

用酶联免疫吸附法(ELlSA)检测食品中黄曲霉毒素B1(A FB1)含量,关键在于样品的前处理。针对大米、食用油中A FB1的前处理作了一些改进。结果表明改进后的前处理检测灵敏度达0.1ug/kg,平均回收率在78%￣120%之间,相对标准偏差小于5.0%。     

ELISA法检测五类食品中黄曲霉毒素B1前处理方法的改进研究

用酶联免疫吸附法(ELISA)检测五类食品(酱油、醋、面粉、大米、食用油)中黄曲霉毒素B_1(AFB_1)含量,关键在于样品的前处理。本文针对五类食品中AFB_1的前处理作了方法学研究。结果表明,改进后的前处理使检测灵敏度达0.1μg/kg,在0.1～10μg/kg之间呈良好线性关系,平均回收率在75%～170%之间。     

烹调食品中杂环胺检测的样品前处理方法研究

杂环胺作为一类在烹调过程中产生的强致癌,高突变活力的物质,越来越受到科研工作者的关注。本文主要对食品中杂环胺检测的前处理技术进行了综述,介绍了从不同样品基质中进行提取和预浓缩的分析策略,如常用的液液萃取,液固萃取,固相萃取,在线串联液液萃取和固相萃取等前处理方法,重点讨论了在样品处理过程中的吸附剂和溶剂选择的问题,讨论了分析技术所需要的条件和最能达到准确结果的方法。     

食品中花生过敏原及其检测方法的研究进展

花生是常见的过敏原之一,能够引起严重的过敏反应。由于缺乏明确的治疗花生过敏的方法,只能让花生过敏患者尽量避免食入含有花生的食物。但在实际的生产过程中,食品加工往往需要经过复杂的生产工艺,会造成食品之间的交叉污染,部分食品难以准确判断是否含有花生过敏原。因此对于食品中花生过敏原的检测方法的开发就显得尤为重要。本文主要对花生中过敏原的种类及其检测方法的研究进展进行了综述,主要对以下几种方法做了介绍,包括酶联免疫吸附法(ELISA)、免疫印迹法、聚合酶链式反应(PCR)等,以及新兴的生物传感器和质谱法,并对检测方法的未来发展趋势进行了展望。     

Influence of baking time and matrix effects on the detection of milk allergens in cookie model food system by ELISA

Milk allergens are common allergens occurring in foods, therefore raising concern in allergic consumers. Enzyme-linked immunosorbent assay (ELISA) is, to date, the method of choice for the detection of food allergens by the food industry although, the performance of ELISA might be compromised when severe food processing techniques are applied to allergen-containing foods. In this paper we investigated the influence of baking time on the detection of milk allergens by using commercial ELISA kits. Baked cookies were chosen as a model food system and experiments were set up to study the impact of spiking a matrix food either before, or after the baking process. Results revealed clear analytical differences between both spiking methods, which stress the importance of choosing appropriate spiking methodologies for method validation purposes. Finally, since the narrow dynamic range of quantification of ELISA implies that dilution of samples is required, the impact of sample dilution on the quantitative results was investigated. All parameters investigated were shown to impact milk allergen detection by means of ELISA.     

Reduction of allergenic properties of shrimp (Penaeus Vannamei) allergens by high intensity ultrasound

The tropomyosin fraction of shrimp proteins is potentially responsible for an allergic reaction in individuals with a genetic predisposition to allergy. However, there are no efficient and safe methods to reduce its allergenicity. High-intensity ultrasound is known to change the structure of proteins. The aim of this study was to assess the effect of high-intensity ultrasound on the IgE-binding capacity of shrimp protein extracts (PE) and of major shrimp allergen Pen a 1(tropomyosin). Peeled shrimp (Penaeus vannamei) muscle was sealed in a plastic bag and treated with high-intensity ultrasound (30 Hz, 800 W) for 1.5 h at 0 and 50 °C, respectively; others were treated with boiling water for 15 min. Then PE and Pen a 1 were made with treated shrimp muscle. The allergenicity of PE and purified allergen from different-treated shrimp were analyzed by the enzyme allergosorbent test (EAST) and competitive inhibition ELISA (Ci-ELISA) using sera of 15 shrimp-allergic patients. PE from high-intensity ultrasonic treatment at 50 °C (treated 2) shrimp was 2.2-fold, 2.5-fold lower respectively than that of untreated shrimp and high-intensity ultrasonic treatment at 0 °C (treated 1) shrimp. While PE from heated (treated 3) shrimp was 1.2-fold lower than that of untreated shrimp. The (Concentration of the different-treated sample that inhibit 50% of the IgE binding to coated untreated sample) IC₅₀ ratios of Pen a 1 prepared from treated 2 shrimp, treated 1 shrimp and treated 3 shrimp to untreated shrimp were 1/15, 1/1.1 and 1/1, respectively. The results suggest that high-intensity ultrasound at 50 °C may reduce the allergenicity of shrimp.     

Increasing extractability of protein for allergen detection after food processing

The food industry is concerned about the presence of hidden allergens or undesired protein residues in final products and has to take measures to comply with current food allergen-labelling regulations. It is known that thermal processing decreases protein solubility and hinders the accuracy of their quantitation. The objective of this study was to optimise the extraction step before quantitation. Almonds were roasted at several temperatures (230, 260 and 400 °C) for 10 min and ground to meals, defatted and extracted with water, PBS and PBST for 30 min at 25 °C, 40 °C, 60 °C and 70 °C, respectively. The extracts were then sonicated in a temperature-controlled water bath and aliquots were taken after 0, 1, 3, 5 and 10 min of sonication. Ultrasonic treatment improved protein extraction from almonds, especially those roasted at 260 and 400 °C. The temperature of the extraction buffer proved to be important, with higher yields at 60 and 70 °C. Use of a higher temperature, with sonication for 5–10 min, increased the amount of protein extracted with PBST (from 141% to 174% for almonds roasted at 260 °C and 287% to 333% for almonds roasted at 400 °C). The BCA assay was used to measure the amount of soluble almond protein. Improved extraction of almond proteins from processed samples is presented.     

N,O-Carboxymethyl Chitosan: An Innovation in New Natural Preservative from Shrimp Shell Waste with a Nutritional Value and Health Orientation

This research has been done to modify chitosan into its derivatives, i.e. N,O-Carboxymethyl Chitosan. The characterization of chitosan and N,O-Carboxymethyl Chitosan, which includes analysis using FTIR, SEM, and XRD, showed that the a natural preservative N,O-Carboxymethyl Chitosan had formed. Our data indicated that addition of N,O-Carboxymethyl Chitosan to samples of chicken meat could be regarded as a solution to increase fiber contents, resilience of food storage, and stability of nutrients (lowering levels of dry substances), lower ash contents, increase protein contents, keep fat contents, as well as increase levels of Nitrogen-Free Extract. Therefore, we conclude that the N,O-Carboxymethyl Chitosan can be used as a preservative which also orients towards nutritional values and health.     

中国食物过敏原数据库的建立与应用

目的氨基酸序列相似性等生物信息学分析方法是转基因食品致敏性评价的重要环节,为了简化转基因食品致敏性生物信息学分析的流程,我们建立了中国食物过敏原数据库。方法将多个数据库中关于过敏原的信息进行了整合并进行本地存储。通过web语言PHP、web服务器Apache和MySQL数据库管理系统进行搭建数据库。结果建成了中国食物过敏原数据库,收集到1498条已知过敏原的记录,数据库发布在hap://175.102.8.19:8001/site/index。结论该数据库可以为科研人员提供免费的、快速的、一站式的转基因食品致敏性分析信息服务。     

实施HACCP的必要基础程序(待续)

为推动我国HACCP的实施,从GMP、化学品控制、清洗和消毒、微生物控制、水的安全、空气的安全、卫生设计、预防性维护、产品溯源和回收、虫害控制、接收、贮存和运输控制、供应商控制、食品安全培训、设备的校准、消费者食品安全的投诉及审核和监督程序16个方面阐述了必要基础程序所包含的具体内容,尤其是对生产控制中容易忽视的过敏原问题进行了较为详细的阐述。为食品生产企业建立食品安全保障体系提出了一些建议,可作为卫生监督员的现场审核的参考。