Mechanism of the reduced allergenicity of shrimp (Macrobrachium nipponense) by combined thermal/pressure processing: Insight into variations in protein structure, gastrointestinal digestion and immunodominant linear epitopes

This study aimed to explore the underlying mechanism about combined thermal/pressure processing on the allergenicity of shrimp (Macrobrachium nipponense). We analysed sensitizing and eliciting capacities, structural changes, gastrointestinal digestion, and mapped linear epitopes. Mice treated with steamed + reverse-pressure sterilized shrimp exhibited lower specific IgE and IgG1 concentrations, degranulation, vascular permeability, and allergic symptoms than those fed with raw shrimp or steamed shrimp (p < 0.05). Reduced allergenicity of shrimp using combined thermal/pressure processing was not only associated with protein unfolding and exposure of hydrophobic residues, but also related to disruption of immunodominant linear epitopes (Glu177-Ser188 in tropomyosin, Gln361-Ser366 in beta-actin) due to changes in gastrointestinal digestion behavior. Moreover, heat/ digested stable epitopes of arginine kinase were located inside its 3D structure, preventing binding with IgE and maintaining hypoallergenicity following combined processing. Thus, steaming and reverse-pressure sterilization might be an efficient low-allergenic food processing method for Macrobrachium nipponense.

Automated summary

This study investigated the mechanism behind the reduced allergenicity of shrimp (Macrobrachium nipponense) when subjected to combined thermal/pressure processing. The findings revealed that mice treated with steamed + reverse-pressure sterilized shrimp exhibited lower allergic reactions compared to those fed with raw shrimp or steamed shrimp. This reduction in allergenicity was attributed to protein unfolding, exposure of hydrophobic residues, disruption of immunodominant linear epitopes, and the heat/digestion stability of certain epitopes.