Pea protein-quercetin glycoside complexes: Interaction, foaming and emulsifying properties

Quercetin (Qu), Quercitrin (Que) and Rutin (Ru) were advisedly selected to explore the interaction of flavonoids with pea protein (PP) by spectral analysis and molecular simulation. The order of binding affinity at 298 K for the flavonoids with PP was Qu (2.26 × 105 M−1) > Ru (8.23 × 104 M−1) > Que (7.93 × 104 M−1), introducing one or two glycosides weakened the affinity. Thermodynamic analysis indicated that the dominant interaction of flavonoids with PP were hydrogen bond and Van der Waals force, which supported by the results of molecular docking simulations. Moreover, decreased surface hydrophobicity and the changed of circular dichroism showed that the conformation of PP became looser with the addition of flavonoids, then the surface tension was decreased, foaming and emulsifying properties of PP were improved. This result may be beneficial to the application of natural flavonoid nutraceuticals and improvement of protein-based food quality properties.