Characterization of physicochemical and immunogenic properties of allergenic proteins altered by food processing: a review

Abstract

Food allergens are mainly naturally-occurring proteins with immunoglobulin E (IgE)-binding epitopes. Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity. We here discuss the impacts of food processing technologies on the modification of physicochemical, structural, and immunogenic properties of allergenic proteins. Detection techniques for characterizing changes in these properties of food allergens are summarized. Food processing helps to reduce allergenicity by aggregating or denaturing proteins, which masks, modifi es, or destroys antigenic epitopes, whereas, it cannot eliminate allergenicity completely, and sometimes even improves allergenicity by exposing new epitopes. Moreover, most food processing techniques have been tested on purifi ed food allergens rather than food products due to potential interference of other food components. We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profi le.

Dietary Polyphenols, Plant Metabolites, and Allergic Disorders: A Comprehensive Review

“…Polyphenols and food allergens, whether covalent or non-covalent, may alter the spatial structure of the allergenic protein, which in turn decreases the allergen’s IgE-binding capacity and, by extension, its sensitization potential [ 112 , 113 ]. To reduce allergenicity, certain polyphenols can bind to nucleophilic amino acids to mask linear allergen epitopes and modify the secondary and tertiary protein structure to change the conformational epitopes in allergens [ 114 , 115 , 116 ]. The main allergen in cow milk, β-lactoglobulin, has been the subject of numerous studies that have shown that, when it is covalently conjugated with different polyphenols, such as rutin, ferulic acid, caffeic acid, epigallocatechin (EGCG), and chlorogenic acid, it causes conformational changes in the protein, leading to a more unfolded structure and a decreased ability to bind IgG and IgE [ 117 , 118 , 119 , 120 , 121 ].…”

“…Conversely, allergen binding is effective when there are fewer polyphenol molecules than allergen reaction sites because polyphenols can form cross-linked protein polymers. This results in more stable and effective polyphenol–allergen complexes [ 115 , 135 ]. Several excellent studies that examined the structural and functional characteristics of soybean globulins following covalent interaction with polyphenols such as EGCG, chlorogenic acid, caffeic acid, gallic acid, and tannic acid [ 136 , 137 , 138 ] provided clear evidence of this occurrence.…”