Homologous non-covalent binding mechanism of potato protein and purple potato anthocyanins: Insights into structural and functional benefits

Abstract

The binding of plant polyphenol and protein possesses great potential to improve their functional properties and utilization value. In this study, homologous non-covalent binding of potato protein (PP) and purple potato anthocyanins (PPA) were performed with an emphasis on the structural and functional benefits of PP/PPA complex. Results demonstrated that the turbidity of PP/PPA complexes increased significantly as PPA concentration increased from 0 to 20 mg/mL. Both particle size (42.6 nm to 19.0 nm) and Zeta potential (−6.05 mV to −11.25 mV) exhibited concentration-dependent decreases. The incorporation of PPA could lead to a dramatically increase in emulsifying activity from 41 m²‧g⁻¹ to 610 m²‧g⁻¹, an increase of 1.5 times in foamability and the significantly decreased surface hydrophobicity, accompanying with excellent antioxidant and antibacterial properties. The PP/PPA complexes also resulted in significantly enhanced disulfide bond and molecular flexibility. Structural characterization and molecular simulations confirmed that PP/PPA stabilized its secondary and tertiary conformations primarily through intermolecular forces, including van der Waals interactions, hydrogen bonding, and hydrophobic interactions. Those interactions contributed to the formation of a more stable and compact structure. The findings demonstrated that PP/PPA complex led to the obviously enhanced functional properties, thereby highlighting its potential for developing novel food applications.