Effects of the covalent conjugation between caffeic acid and peanut allergen protein Ara h1 on the antigenicity and structure of Ara h1.

Ara h1 was the highest content of peanut allergen protein, identified as a biomarker of peanut allergen. In this study, Ara h1 was covalently complexed with caffeic acid (CA) to research the effects of covalent conjugation on the antigenicity and protein structural properties of Ara h1. After the covalent complexing of Ara h1 and CA, the IgG-binding capacity of Ara h1 was reduced compared with that of control Ara h1. Moreover, the structure of Ara h1 changed from ordered to disordered, the number of intermolecular hydrogen bonds decreased, and some hydrophobic groups were exposed or hydrophobic peptides were released. The carboxyl group in CA reacted with the amino group in Ara h1. The digestibility of Ara h1-CA was increased. The antigenicity of Ara h1-CA was undetectable after 30 min of digestion in vitro. These findings can serve as a reference for further research on hypoallergenic peanut products.