Effects of (−)-Epigallocatechin-3-gallate non-covalent binding on the functional and structural properties of pumpkin seed protein isolate

Pumpkin seed protein isolate (PSPI), an emerging plant-based protein, has attracted attention, but more exploitation is needed to unlock its potential. To investigate whether (-)-Epigallocatechin gallate (EGCG) could improve PSPI properties, physicochemical and interaction analyses were conducted. Results showed EGCG significantly enhanced foaming, emulsification, and gelling properties of PSPI, especially gel strength. At a 1:20 EGCG molar ratio, hardness, adhesion, and elasticity of PSPI gels increased by 46.8-fold, 27.7-fold, and 64.5%, respectively. EGCG reduced tan δ and water mobility, likely aiding gel crosslinking. It decreased surface hydrophobicity and induced local conformational changes, likely increasing PSPI molecular flexibility and improving properties. Binding constant <i>K</i> _a indicated dynamic quenching and hydrophobic-driven binding. MD simulations revealed hydrophobic interactions and hydrogen bonds dominated EGCG binding, with arginine residues playing a key role. This study shows EGCG non-covalent binding is an effective PSPI modification strategy, broadening its use as a functional plant-based protein in food industry.