Characterization of pea protein-different types of glycoside flavonoid complex interactions and functional properties

Flavonoids offer various health benefits due to their chemical properties and non-covalent interactions with food nutrients. Despite extensive research on flavonoid-protein interactions, the effects of flavonoid glycosides on pea protein (PP) remained unclear. This study explored the non-covalent interactions of luteolin (Lu), isoorientin (Iso), and cynaroside (Cyn) with PP using molecular docking and multi-spectral techniques. Results showed that Lu interacted with PP mainly through hydrophobic forces, while Iso and Cyn interacted predominantly via hydrogen bonding. At 298 K, the binding affinity of flavonoids to PP was ranked as Lu (16.98 × 10⁴ M^-1) > Iso (7.41 × 10⁴ M^-1) > Cyn (6.31 × 10⁴ M^-1). Circular dichroism analysis showed that flavonoid glycosides loosened the protein structure by inducing a change in the secondary structure of PP from an α-helix to a random coil. This resulted in improved foaming, emulsification, and antioxidant properties of PP. This study provided insights into flavonoid-protein interactions and their potential applications in functional protein foods.