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 β-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.