60Co-γ射线辐照诱导下猪肉过敏原PSA致敏性变化及其机理研究

The impact of food allergies on public health has become a public health and food safety issue of global concern. Although meat allergy is considered to be a rare pathological problem, recent reports have demonstrated that meat allergy has become a new and important food safety issue. Recently, beef allergy has received extensive attention. However, in our country, few studies are reported to reduce the allergenicity of porcine serum albumin (PSA), pork major allergen. In order to avoid the occurrence of meat allergy, many researchers have focused on the effects of different treatments such as high temperature, high pressure, ultrasound, enzymolysis, and irradiation and so on. Among them, irradiation is considered as a meaningful method for sterilization and preservation of meat and meat products, and has potential role in reducing risk of food allergy. It has been reported that gamma irritation could be applied to less-allergenic meat products. However, few researches have been conducted to investigate changes in allergenicity and structure of PSA by gamma irradiation. In this study, the major allergen of pork, PSA, is chosen as an object. The effects of 60Co gamma-ray irradiation on the allergen structure, kinetics and thermodynamics of antigen-antibody interactions will be further studied in depth using multiple technologies such as surface plasmon resonance (SPR) biosensor, western blot, and spectroscopies. The study aims to clarify the effects and mechanism of gamma irradiation eliminating or decreasing food allergenicity in meat and meat products, and intends to provide the theoretical basis for the research and development of hypoallergenic and nonallergenic foods.

食物过敏对公众健康的影响已成为全世界关注的公共卫生问题和食品安全问题。肉类食物引发的过敏反应虽较为罕见，但最近报告显示，肉类过敏已成为一种新的重要的食品安全问题。近年牛肉过敏症已受到广泛关注，但作为世界产量和消费量较高的猪肉，其引起的过敏反应却未得到应有的重视和评价。为避免消费者发生食物过敏，研究者采用高温、高压、超声、酶解、辐照等降低其致敏性。辐照作为肉品杀菌保鲜的一条具有实用意义新途径，并具有降低食物致敏潜力。据报道，肉类过敏原经辐照后其致敏性发生改变。但目前针对辐照诱导下猪肉重要过敏原PSA致敏性及其结构变化等均缺乏系统研究。本项目以过敏原PSA为对象，基于SPR生物传感器、免疫印迹和光谱学等技术，深入研究60Co-γ射线辐照诱导下PSA结构变化，抗原抗体的结合力及互作的动力学和热力学，阐明辐照降低或消除猪肉及其制品中过敏原致敏性的效应和机理，以期为低敏或脱敏食品的研发提供理论依据。

食物过敏已成为全球关注的公共卫生问题。肉类过敏虽鲜有报道，但最近报告显示，肉类过敏已成为食品安全的新问题。中国作为全球最大的猪肉生产和消费国，但迄今我国有关猪肉致敏问题尚未得到应有的重视和评价。据报道，辐照可对食品进行灭菌及保鲜，还能降低其致敏性。但目前针对辐照诱导下猪肉过敏原PSA致敏性变化及其机理缺乏深入系统的研究。本项目以猪肉过敏原PSA为研究对象，深入探讨60Co-γ辐照诱导下过敏原PSA的结构变化、抗原抗体结合力及互作的动力学和热力学，旨在阐明辐照降低猪肉及制品中过敏原致敏性的效应和机理。本项目采用WB、Ci-ELISA和SPR技术，系统分析60Co-γ辐照对过敏原PSA致敏性的影响。结果表明：过敏原PSA经辐照处理后其致敏性降低，抗原抗体的结合力由疏水作用力转变为静电引力，两者亲和力变弱而发生解离。辐照对过敏原PSA蛋白构象的影响采用SDS-PAGE电泳、CD光谱、紫外光谱和荧光光谱来进行表征。过敏原PSA经辐照处理后其一级结构遭到破坏；过敏原PSA的α-螺旋含量随辐照剂量的增加而显著减少，二级结构发生改变；过敏原PSA的表面巯基含量随辐照剂量的增加呈先上升后下降的趋势，由此推测蛋白分子先发生伸展而后重新缔合或聚集；过敏原PSA的紫外吸收值随辐照剂量的增加呈上升趋势；而过敏原PSA的荧光强度随辐照剂量的增加而降低，其最大发射峰还发生蓝移。这表明辐照可改变过敏原PSA的蛋白构象，掩盖或破坏其抗原决定簇，从而导致其致敏性降低。辐照/辐照-酶解对猪肉及制品（火腿、香肠和鲜猪肉）脱敏效果的影响则采用模拟体外胃肠液消化、WB和Ci-ELISA来进行系统评价。辐照可有效降低猪肉过敏原PSA的消化稳定性和致敏性，但其降解产物仍可能引发过敏反应的发生；猪肉过敏原PSA经辐照处理后，其蛋白质的分子结构遭到破坏，更易于被胃蛋白酶和胰蛋白酶消化；辐照在降低过敏原PSA致敏性方面，对鲜猪肉（含水量高）的影响更为显著。因此，60Co-γ辐照在降低猪肉过敏原致敏性方面具有巨大潜力，有望为低敏或脱敏猪肉及制品的开发提供新的探索途径。