Molecular fragmentation of wheat-germ agglutinin induced by food irradiation reduces its allergenicity in sensitised mice

Allergenicity of wheat protein in diet: Mechanisms, modifications and challenges

Wheat is widely available in people's daily diets. However, some people are currently experiencing IgE-mediated allergic reactions to wheat-based foods, which seriously impact their quality of life. Thus, it is imperative to provide comprehensive knowledge and effective methods to reduce the risk of wheat allergy (WA) in food. In the present review, recent advances in WA symptoms, the major allergens, detection methods, opportunities and challenges in establishing animal models of WA are summarized and discussed. Furthermore, an updated overview of the different modification methods that are currently being applied to wheat-based foods is provided. This study concludes that future approaches to food allergen detection will focus on combining multiple tools to rapidly and accurately quantify individual allergens in complex food matrices. Besides, biological modification has many advantages over physical or chemical modification methods in the development of hypoallergenic wheat products, such as enzymatic hydrolysis and fermentation. It is worth noting that using biotechnology to edit wheat allergen genes to produce allergen-free food may be a promising method in the future which could improve the safety of wheat foods and the health of allergy sufferers.

Non-thermal processing of cashews: irradiation reduces allergenicity by altering the structure of Ana o 3

Traditional thermal processing of cashews not only results in nutrient loss and harmful by-products, but also does not significantly reduce allergenicity. Irradiation could be an important non-thermal processing method to reduce cashew allergens' allergenicity and retain their nutritional properties. This study aimed to evaluate the effects of gamma irradiation processing on the structure and potential allergenicity of Ana o 3. The Ana o 3 solutions were gamma-irradiated at 0, 1, 3, 5, and 10 kGy. The structure change was monitored by Tricine-SDS-PAGE, circular dichroism spectroscopy, and fluorescence spectroscopy. The potential allergenicity was tested by immunoblotting, indirect competitive ELISA, and the human basophil KU812 degranulation assay using serum from cashew allergy patients. The results of CD spectroscopy showed that the content of α-helices decreased from 46.8% to 30.9% after 3 to 10 kGy, while the content of random coils increased from 23.7% to 33.3%. Meanwhile, a large number of hydrophobic regions were exposed, resulting in an increase in the hydrophobic surface of the protein. In terms of allergenicity, the IC₅₀ values obtained by the competitive inhibition ELISA after irradiation increased from 0.628 to 4.054 μg mL^-1, indicating that irradiation reduced the IgE binding capacity of Ana o 3, which was consistent with the results of western blotting. In addition, the basophil degranulation analysis showed that the release of IL-6, TNF-α, and histamine was decreased. It was shown that the potential allergenicity of the irradiated Ana o 3 was remarkably decreased since irradiation could mask or destroy the allergen epitopes, providing a new approach to reduce the allergenicity of cashew products.

Detection of Lectin Protein Allergen of Kidney Beans (Phaseolus vulgaris L.) and Desensitization Food Processing Technology

With the increase of food allergy events related to not properly cooked kidney beans (Phaseolus vulgaris L.), more and more researchers are paying attention to the sensitization potential of lectin, one of the major storage and defensive proteins with the specific carbohydrate-binding activity. The immunoglobulin E (IgE), non-IgE, and mixed allergic reactions induced by the lectins were inducted in the current paper, and the detection methods of kidney bean lectin, including the purification strategies, hemagglutination activity, specific polysaccharide or glycoprotein interactions, antibody combinations, mass spectrometry methods, and allergomics strategies, were summarized, while various food processing aspects, such as the physical thermal processing, physical non-thermal processing, chemical modifications, and biological treatments, were reviewed in the potential of sensitization reduction. It might be the first comprehensive review on lectin allergen detection from kidney bean and the desensitization strategy in food processing and will provide a basis for food safety control.

Irradiation technology: An effective and promising strategy for eliminating food allergens

Food allergies are one of the major health concerns worldwide and have been increasing at an alarming rate in recent times. The elimination of food allergenicity has been an important issue in current research on food. Irradiation is a typical nonthermal treatment technology that can effectively reduce the allergenicity of food, showing great application prospects in improving the quality and safety of foods. In this review, the mechanism and remarkable features of irradiation in the elimination of food allergens are mainly introduced, and the research progress on reducing the allergenicity of animal foods (milk, egg, fish and shrimp) and plant foods (soybean, peanut, wheat and nuts) using irradiation is summarized. Furthermore, the influencing factors for irradiation in the elimination of food allergens are analyzed and further research directions of irradiation desensitization technology are also discussed. This article aims to provide a reference for promoting the application of irradiation technology in improving the safety of foods.

Food irradiation: a promising technology to produce hypoallergenic food with high quality

The increasing incidence of food allergy cases is a public health problem of global concern. Producing hypoallergenic foods with high quality, low cost, and eco-friendly is a new trend for the food industry in the coming decades. Food irradiation, a non-thermal food processing technology, is a powerful tool to reduce the allergenicity with the above advantages. This review presents a summary of recent studies about food irradiation to reduce the allergenicity of food, including shellfish, soy, peanut, milk, tree nut, egg, wheat and fish. Principles of food irradiation, including mechanisms of allergenicity-reduction, irradiation types and characteristics, are discussed. Specific effects of food irradiation are also evaluated, involving microbial decontamination, improvement or preservation of nutritional value, harmful substances reduction of food products. Furthermore, the advantages, disadvantages and limitations of food irradiation are analyzed. It is concluded that food irradiation is a safety tool to reduce the allergenicity of food effectively, with high nutritional value and long shelf-life, making it a competitive alternative technology to traditional techniques such as heating treatments. Of note, a combination of irradiation with additional processing may be a trend for food irradiation.

Effects of Low-pH Treatment on the Allergenicity Reduction of Black Turtle Bean (Phaseolus vulgaris L.) Lectin and Its Mechanism

A high content of potentially allergenic lectin in Phaseolus vulgaris L. beans is of increasing health concerns; however, understanding of the protein allergenicity mechanism on the molecular basis is scarce. In the present study, low-pH treatments were applied to modify black turtle bean lectin allergen, and a sensitization procedure was performed using the BALB/c mice for the allergenicity evaluation, while the conformational changes were monitored by the spectral analyses and the details were explored by the molecular dynamics simulation. Much milder anaphylactic responses were observed in BALB/c mice experiments. At the molecular level, the protein was unfolded in low acidic environments because of protonation, and α-helix was reduced with the exposure of trypsin cleavage sites, especially the improvement of protease accessibility for Lys121, 134, and 157 in the B cell epitope structural alterations. These results indicate that a low-pH treatment might be an efficient method to improve the safety of legume protein consumption.

Bridging the Knowledge Gap for the Impact of Non-Thermal Processing on Proteins and Amino Acids

Proteins represent one of the major food components that contribute to a wide range of biophysical functions and dictate the nutritional, sensorial, and shelf-life of food products. Different non-thermal processing technologies (e.g., irradiation, ultrasound, cold plasma, pulsed electric field, and high-pressure treatments) can affect the structure of proteins, and thus their solubility as well as their functional properties. The exposure of hydrophobic groups, unfolding followed by aggregation at high non-thermal treatment intensities, and the formation of new bonds have been reported to promote the modification of structural and functional properties of proteins. Several studies reported the reduction of allergenicity of some proteins after the application of non-thermal treatments. The composition and concentration of free amino acids could be changed after non-thermal processing, depending on the processing time and intensity. The present review discusses the effects of different non-thermal treatments on protein properties in detail, and highlights the opportunities and disadvantages of these technologies in relation to protein functionality.

Effect of gamma irradiation on soybean allergen levels

The levels of food allergens in gamma-irradiated soybean (0, 2.5, 5, 7.5, 10, 20, and 30 kGy) were investigated by immunoblotting and ELISA, using allergen-specific antibodies and patient serum. After 3 months of storage, Coomassie brilliant blue (CBB) staining indicated similar total protein profiles among the treatments, but that some proteins were degraded by irradiation at high doses. Immunoblotting with specific antibodies for major soybean allergens (β-conglycinin, Gly m Bd 30 K, soybean trypsin inhibitor, and Gly m 4) resulted in apparent band profiles and intensities that were not significantly changed by irradiation. Competitive inhibition ELISA analyses suggested that there were no significant changes in the allergen contents, except for a decrease in the soybean trypsin inhibitor. The patient IgE binding allergenic protein patterns were not changed by irradiation up to 30 kGy. ELISA using patient serum also revealed that the IgE reactivity to the irradiated soybean extract did not increase from the level of the control, but that the reactivity to some patient serum IgE was significantly decreased by irradiation.