Focusing on the impact of chlorogenic acid covalent binding on the fibrillation properties of pea vicilin and legumin globulins

Despite their potential as sustainable plant protein sources, the functionality of pea vicilin (7S) and legumin (11S) globulins is often limited by their compact structures. Covalent modification with chlorogenic acid (CGA) represents a promising strategy for functional enhancement. In this study, a comparative analysis was conducted to elucidate the covalent binding mechanisms of CGA with pea 7S and 11S, revealing their divergent impacts on fibrillation capacity. The results indicated that the 1′-H group of CGA served as the grafting site, covalently docking to LysB30 of 7S and CysA318 of 11S to form C N and C S bonds, respectively. The binding amount of CGA was concentration-dependent, reaching a maximum of 70.2 μM/g for the 11S-CGA covalent complex and 46.2 μM/g for the 7S-CGA covalent complex. Regarding fibrillation properties, covalent binding of CGA inhibited the fibrillation of both pea globulins by suppressing fiber elongation and reducing surface hydrophobicity, thereby decreasing the viscosity of the fiber networks. Moreover, covalently bound CGA endowed both protein fibers with enhanced antioxidant capacity in a concentration-dependent manner. Overall, these results demonstrate that covalent polyphenol modification can effectively regulate the fibrillation properties of pea 7S and 11S globulins, thereby expanding the functionality of pea protein derived products.