小麦蛋白过敏原的研究进展

小麦过敏是人们日益关注的食品安全的关键问题之一,如何降低小麦的致敏性,已成为食品安全领域迫切需要解决的科学问题。本文介绍了小麦致敏原的种类和表位以及小麦脱敏方面的研究进展,小麦致敏原的主要检测技术包括酶联免疫吸附技术、免疫印迹技术、蛋白组学技术。本文对提高小麦制品的品质安全具有重要意义,为开发低致敏性小麦制品提供了参考。     

Potential efficacy of processing technologies for mitigating crustacean allergenicity

ABSTRACT

Crustacean allergy has become a growing food safety concern at a global scale. In the past decades, various food processing approaches have been employed to develop food products with reduced allergenic potential. Thermal treatment can dramatically influence the allergenicity of crustaceans by either reducing or enhancing their allergenic potential. Maillard reaction, enzymatic and acid treatments have shown to be promising in mitigating crustacean allergenicity. Recently, novel processing technologies, namely high-pressure processing, high-intensity ultrasound, irradiation, pulsed ultraviolet light and hurdle technology have attracted special attention from the researchers and the food industry professionals owing to their benefits over the conventional methods. In this context, this review paper provides an updated overview of the current knowledge on how different food processing methods induce structural changes of crustacean allergens and, subsequently, influence their allergenic potential. Data on prevalence and clinical relevance of crustacean allergy are presented, as well as, the molecular characterization of crustacean allergens and the main analytical methods for their detection in processed foods.     

儿童食物过敏及其饮食干预治疗研究进展

食物过敏是指由人体免疫系统介导的食物不良反应,常见皮肤、消化道、呼吸道症状,如特应性鼻炎等疾病,严重会出现休克等现象。儿童作为食物过敏易感人群,其生长发育极易受到影响,并且近年来全球儿童食物过敏人群逐年增长,因此对于儿童食物过敏进行预防和治疗有着十分重要的意义。但目前关于儿童食物过敏的流行病学资料仍然比较缺乏,通过查阅中英文文献,本文对儿童食物过敏的常见致敏食物、过敏机制、发病因素及诊治方法进行综述,为食物过敏的预防和治疗方向提供一定的理论依据。     

Milk allergens, their characteristics and their detection in food: A review

Cow's milk allergy (CMA) is one of the most common food allergies in childhood. This allergy is normally outgrown in the first year of life, however 15% of allergic children remain allergic. Many studies have been carried out to define and characterise the allergens involved in CMA and described two major allergens: casein (αs1-CN) and β-lactoglobulin. In addition to this, many other milk proteins are antigenic and capable of inducing immune responses. Milk from sheep or goats differs from cow's milk (CM) in terms of composition and allergenic properties. Food processing such as heating affects the stability, structure and intermolecular interactions of CM proteins, thereby changing the allergenic capacity. Chemical and proteolytic treatments of milk to obtain milk hydrolysates have been developed to reduce allergic reactions. Prevention of CMA largely relies on avoidance of all food products containing cow's milk. To achieve this, interest has focused on the development of various technologies for detecting and measuring the presence of milk allergens in food products by immunoassays or proteomic approaches. This review describes the technologies implemented for the analysis of milk allergens (allergenicity, biochemistry) as well as their potential detection in food matrices.     

Relative immunogenicity of commonly allergenic foods versus rarely allergenic and nonallergenic foods in mice

Food allergies affect 6 to 8% of children and 2% of adults in the United States. For reasons that are not clear, eight types of food account for a vast majority (approximately 90%) of food-induced hypersensitivity reactions. In this study, C57Bl/6 mice were used to test the hypothesis that commonly allergenic foods are intrinsically more immunogenic than rarely allergenic or nonallergenic foods in allergy-susceptible hosts. Groups of mice (n = 4 to 5) were injected intraperitoneally with the protein extracts (plus alum as an adjuvant) from chicken eggs, peanuts, almonds, filberts-hazelnuts, walnuts, soybeans, and wheat (commonly allergenic foods) and coffee, sweet potatoes, carrots, white potatoes, cherries, lettuce, and spinach (rarely allergenic and nonallergenic foods). Primary and secondary immune responses (as measured by specific IgG1 antibody serum levels) were measured by an enzyme-linked immunosorbent assay. Proteins from peanuts, almonds, filberts, sweet potatoes, cherries, and spinach elicited robust primary and/or secondary immune responses. Proteins from eggs, walnuts, and lettuce elicited poor primary responses but significant secondary responses. In contrast, wheat, soybeans, coffee, carrots, and white potatoes elicited barely detectable to poor primary and secondary immune responses. The order of the immunogenicity levels of these foods in mice is as follows: almonds = filberts > spinach (Rubisco) > peanuts > or = sweet potatoes > cherries > lettuce > walnuts > chicken eggs > carrots > or = white potatoes > wheat = coffee = soybeans. In summary, these data demonstrate for the first time that: (i) foods vary widely with regard to their relative immunogenicity in allergy-susceptible hosts and (ii) intrinsic immunogenicity in mice does not distinguish commonly allergenic foods from rarely allergenic or nonallergenic foods.     

Development of a Biological Assay to Determine the Allergenic Potential of Foods

Food allergies represent a risk for many people in industrialized countries. Unrecognizable allergenic proteins of foodstuffs may be present as ingredients that are not labeled or as unknown cross-contamination. Such hidden allergens can cause severe reactions in allergics, even at minute quantities, sometimes with fatal outcome. For the verification of the presence of allergenic food constituents, analytical methods such as ELISA and PCR have been developed. However, these tests cannot measure allergenic potential. For this reason, a test system that measures the biological activity of allergens has been developed. It is based on the cellular mechanisms of the type I allergy. Rat basophilic leukemia cells (RBL-2H3) were transfected with the genes of the human high affinity receptor for IgE. The resulting cell line expressed the human receptor α-chain and could bind allergenspecific IgE from allergic subjects, in contrast to the parent cell line. After cross-linking of receptor-bound, allergen-specific human IgE by allergens, the cells released measurable inflammatory mediators. These cells were used for the analysis of a variety of allergen extracts, including extracts prepared from foods containing allergenic hazelnut and peanut. The comparative validation with existing ELISA and PCR for hazelnut and peanut demonstrated similar sensitivity and specificity. The established cell line will be a novel tool in the detection of allergens in complex mixtures, especially to address the issue of their allergenic potential, which cannot be accomplished by classical analytical methods. This will add valuable information about the allergenic potential of food constituents to the risk assessment of foods.     

植物多酚与花生致敏蛋白相互作用及脱敏机理研究进展

花生过敏是最主要的食物过敏类型之一,花生致敏蛋白是主要致敏物质。当前解决花生过敏的方法如热加工法、基因工程方法和酶处理法等存在效率低,安全风险高、易破坏营养成分等缺点。植物多酚是一种天然植物活性物质,具有广泛的生理功能,如抗氧化、降糖、抗炎等,利用植物多酚与花生致敏蛋白相互作用是解决花生过敏的一项新途径,已有文献报道植物多酚具有抗过敏作用。本文主要阐述植物多酚与花生致敏蛋白的相互作用及植物多酚降低花生蛋白致敏性的潜在机理,并对该研究方向进行展望,以期为利用植物多酚解决花生过敏提供新思路。     

Maillard reaction in food allergy: Pros and cons

Food allergens have a notable potential to induce various health concerns in susceptible individuals. The majority of allergenic foods are usually subjected to thermal processing prior to their consumption. However, during thermal processing and long storage of foods, Maillard reaction (MR) often takes place. The MR is a non-enzymatic glycation reaction between the carbonyl group of reducing sugars and compounds having free amino groups. MR may sometimes be beneficial by damaging epitope of allergens and reducing allergenic potential, while exacerbation in allergic reactions may also occur due to changes in the motifs of epitopes or neoallergen generation. Apart from these modulations, non-enzymatic glycation can also modify the food protein(s) with various type of advance glycation end products (AGEs) such as N?-(carboxymethyl-)lysine (CML), pentosidine, pyrraline, and methylglyoxal-H1 derived from MR. These Maillard products may act as immunogen by inducing the activation and proliferation of various immune cells. Literature is available to understand pathogenesis of glycation in the context of various diseases but there is hardly any review that can provide a thorough insight on the impact of glycation in food allergy. Therefore, present review explores the pathogenesis with special reference to food allergy caused by non-enzymatic glycation as well as AGEs.     

牛乳蛋白过敏综述

牛乳过敏(CMA)是一种复杂的无序状态。许多牛乳蛋白均可引起过敏。牛乳蛋白过敏受多种免疫机制驱动。过敏发生率和占主导地位的过敏机制随年龄改变,一般婴儿中易发生IgE介导型过敏,成人过敏多为非IgE介导。CMA真实患者或疑似患者及早避食乳制品和及时给予喂养指导十分重要。本文通过目前对过敏的诱发和免疫机理的了解探讨CMA的流行病学和自然进程。并对过敏反应的初级和次级预防的策略及正在进行的有效彻底治愈CMA的研究进行分析。     

Fish Allergy: Fish and Products Thereof

ABSTRACT: Allergy to fish is a common cause of IgE‐mediated food allergic reactions especially in geographic regions where fish is an important dietary component. Fish allergy is estimated to affect 0.4% of the total population in the United States. All species of fish are believed to be allergenic, but allergic reactions to fish reported in the medical literature are most commonly caused by cod and salmon. The major allergen in fish is a naturally occurring muscle protein called parvalbumin. Some evidence exists of allergic reactions to other fish proteins including collagen. This review addresses fish allergy and fish‐derived ingredients, namely gelatin, isinglass, fish maws, ice‐structuring protein, fish oil, and Worcestershire sauce.     

质谱技术在食物过敏原检测中的研究进展

食物过敏是当前食品安全领域比较突出的问题,相应的过敏原检测方法研究也越来越受重视。相比于传统的免疫学检测方法,质谱技术在检测加工后以及复杂基质中的食物过敏原中,具有高通量和高灵敏性等优点,被广泛应用于食物过敏原的检测。本文主要从定性和定量2方面介绍了质谱技术在食品过敏原检测中的研究进展。相关研究对牛乳、鸡蛋、小麦和榛子(坚果类)等主要食物过敏原均有涉及。在定性研究中,以肽质量指纹图谱法和肽碎片离子鉴定法为主,鉴定食物中的过敏原蛋白。在定量研究中,通过标记/无标记技术,也能够实现对微量的目标蛋白进行相对/绝对定量。质谱技术应用于食物过敏原检测中,将有助于提升过敏原检测能力,降低食物过敏安全风险。     

浅析食源性低聚肽的致敏风险

食源性低聚肽是以食用蛋白为原料水解的产物,分子质量小于1000 u,一般由2~10个氨基酸构成,可不需消化或稍加消化即可吸收,吸收利用率较高。食源性低聚肽具有一些生理活性功能,如抗氧化、抗菌,抑制血管紧张素转换酶活性等。近年来,食源性低聚肽被广泛应用于食品、保健品及化妆品等行业。从理论上来说,一般形成抗原表位至少需要5个氨基酸,由2~10个氨基酸组成的食源性低聚肽能够形成抗原表位而存在IgE介导过敏的潜在风险。据此,本文对可能引起食源性低聚肽致敏风险的因素,如存在抗原表位和可能发生交叉过敏反应进行分析,并对可能用于评价食源性低聚肽致敏性的方法进行介绍,对如何降低食源性低聚肽致敏风险的加工方法进行探讨,为食源性低聚肽的更广泛应用提供理论基础。     

从过敏原危害评估食物过敏风险

随着全球食物过敏发生率的逐年升高,食物过敏性疾病已成为人们日益关注的食品安全和公共卫生问题.本文介绍了食物过敏原特性、致敏机制、临床表现、常见致敏食物及主要暴露来源等内容,概括了食物过敏原闽值及参考剂量的制定方法和最新调整情况,并总结了目前国际上公认的几种食物过敏原的风险评估方法,以期对下一步开展我国人群食物过敏风险评...     

Pistachio nut allergy: An updated overview

Pistachio nut (Pistacia vera) is highly appreciated for its organoleptic characteristics and potential health benefits. However, this tree nut is also responsible for triggering moderate to severe IgE-mediated reactions in allergic individuals. Currently, pistachio nut allergy has gained some special attention, mainly due to its intrinsic relation with cashew nut allergy. Like for other nuts, the prevalence of pistachio nut allergy seems to be increasing at a global scale. Until now, there are five allergenic proteins officially listed for pistachio nut (Pis v 1, Pis v 2, Pis v 3, Pis v 4 and Pis v 5). Relevant data on their biochemical classification has become available, enabling establishing a correlation with the respective clinical symptoms. The establishment of an effective allergen risk assessment is a key issue for the food industry, policy makers and regulatory agencies. Thus, the availability of fast, specific and sensitive methods to detect trace amounts of allergens in processed foods is crucial. In the specific case of pistachio nut, there are some protein- and DNA-based methods for its detection/quantification in foods, which can aid to verify label information. Accordingly, all relevant research advances on this topic were summarised, updated and critically discussed in this review.     

Considerations on Developing Criteria to Determine Whether a Food Allergen is of Public Health Importance

Food allergy is the result of a particular type of immune response against one or more food components, usually proteins. The food allergy reactions that are the focus of regulatory measures are mediated by antibodies of the IgE class. Importantly, food allergy is a two-step process. The first step, the sensitisation phase, consists of an immune response resulting in production of IgE antibodies specific for the allergen. The second step, the provocation phase, is the triggering of a symptomatic allergic reaction as a result of exposure to the allergen after sensitisation has been established. For reasons not well understood, a majority of sensitised individuals never will experience clinical reactions. Determining the number of sensitised individuals (test positives) in a population will therefore grossly overestimate the prevalence of food allergy. The term ‘allergy’ should be used only if clinical reactions occur. For triggering a food allergic reaction in a sensitised individual, only the ‘acute’ food intake and not the intake over time is of importance, and food allergy in this aspect resembles acute poisoning. Because of the cultural, agricultural, economic and nutritional importance of the foods, society accepts that a small fraction of the population develops allergies to traditional food products. Prevention of allergic reactions is then sought by means of education and by labelling of the most important allergenic foods. However, some 200 allergenic foods have been described, but only a small minority of these appears to be of importance in terms of frequency and severity of reactions triggered in the population. When it comes to management of the allergens, however, there is a lack of clear criteria at two levels: at the level of defining what documentation should be required to enter a proposed new food allergen into one of the large allergen databases, as well as at the level of determining which food allergens are of sufficient public health importance to require special regulatory attention in terms of labelling. With the aim of increasing transparency and predictability of decision-making processes and obtaining more consistency between labelling of different allergens as well as between labelling of allergens in different food regulatory jurisdictions, ILSI Europe has taken an initiative to establish clear criteria and a framework to determine the public health importance of a given food allergen. These criteria will consist of factors relating to food properties, population factors, and exposure factors.     

Simultaneous detection of allergenic fish,cephalopods and shellfish in food by multiplex ligation-dependent probe amplification

People suffering from food allergy rely on correct food labelling as the ingestion of minimal amounts of the respective allergen can trigger severe allergenic reactions. Probes for the detection of DNA from allergenic fish, shellfish and cephalopod species in food using multiplex ligation-dependent probe amplification were developed. The specificity and the sensitivity of the detection system were investigated. The limit of detection was 20 mg kg^?1 for scallop, fish and bivalve species and 100 mg kg^?1 for cephalopod, gastropod and crustacean species using self-prepared sushi spiked with the analytes in different concentration levels. The analysis of 10 commercial food samples demonstrates the applicability of the developed method and its suitability for food quality control. Therefore, the method can be used to monitor the compliance with labelling rules regarding food allergens.     

甲壳类水产品过敏原及其致敏性消减技术研究进展

甲壳类水产品味道鲜美,营养丰富,广受消费者喜爱,但可诱发机体产生严重过敏反应,甚至危及生命,已成为全球范围内日益严重的食品安全问题。概述了目前已鉴定的甲壳类水产品过敏原的结构和免疫性质,及其致敏性消减技术原理和研究进展;已报道的甲壳类水产品过敏原有原肌球蛋白、精氨酸激酶、肌质钙结合蛋白、肌球蛋白轻链、磷酸丙糖异构酶和血蓝蛋白等,其中原肌球蛋白为甲壳类水产品的主要过敏原,可与72%~98%的甲壳类食品过敏患者血清产生特异性IgE反应。利用物理加工消减甲壳类水产品过敏原致敏性,主要通过传统热处理、微波、超高压、低温等离子体和辐照等物理作用力诱导蛋白质变性,进而破坏蛋白质的致敏性表位;酸处理和糖基化等化学修饰消减技术可以通过改变过敏原结构、形成新化学键等方式掩盖或直接破坏致敏性表位;酶处理和发酵处理等生物修饰消减技术则直接降解过敏原致敏性表位。未来仍需要通过过敏表位的靶向消减、多种消减技术协同、动物与人体试验开展,探究过敏原结构和表位修饰的影响机制,推进过敏原消减技术的实际应用,为低敏甚至脱敏甲壳类食品的研发提供参考。     

Hypoallergenic Characteristics of Wheat Flour Produced by Stepwise Polishing

Hypoallergenic wheat flour was produced by polished-graded method using a rice polishing machine. Eight fractions (C1–C8) of polished-graded wheat flours were obtained step wise from the outer layer of whole wheat grains by 10% of the total weight, and the distribution of allergenic protein in each fraction was determined. The salt-soluble (albumin/globulin), salt-insoluble (glutenin) and alcohol-soluble (gliadin) proteins obtained from the polished-graded wheat flours were tested for the allergen assay with immunodetection using the sera of wheat allergenic patients. Immunoblotting results confirmed that the innermost fraction (C8) contained a smaller amount of allergenic proteins. Albumin/globulin groups in all fractions (C1–C8) showed different IgE-reactivity patterns, the 60–75 kDa proteins appeared in all of fraction flours. It was higher in C3–C5 fractions. Fractions C3 and C4 contained higher amount of specific wheat allergenic protein including 60–75, 35, 22, and < 20 kDa. IgE-antibody also bound to glutenin (25–37 kDa), especially in C3 and C4, but the binding proteins showed quite faint bands. Gliadin was found in all fractions of wheat flour. We propose that polishing is an appropriate method to obtain hypoallergenic wheat flours, and the fraction C8 may be possible to be consumed by people suffering from wheat allergy.     

食品过敏原快速检测技术方法研究进展

近几年食品行业的立法和监管机构对食品中的过敏成分的检测越来越关注。食品过敏已经成为全球性的食品安全问题,而由其引起的疾病严重影响了人们的正常生活,因而采用合适的方法对其进行检测是十分必要的。对目前有关食品过敏原的免疫学检测方法和核酸检测方法进行了较为全面的综述,并探讨食品中过敏原检测方法的发展前景。