Pterostilbene binding to whey protein: Multi-spectroscopy and the antioxidant activity

In this study, Pterostilbene (Pte) was incorporated into whey protein isolate (WPI) to form a whey protein isolate-pterostilbene (WPI-Pte) complex. The interaction mechanism between these two components and its impact on the antioxidant performance of Pte were investigated through multispectral techniques and molecular docking. UV and fluorescence analyses revealed a distinct fluorescence static quenching mechanism of WPI by Pte, resulting in the formation of a complex with a 1:1 M ratio. Thermodynamic parameter assessments indicated that the interaction between Pte and WPI is a spontaneous non-covalent binding process, primarily driven by hydrophobic interactions, followed by hydrogen bonding. Molecular docking confirmed that Pte molecules become stably embedded within hydrophobic pockets formed by amino acid residues of the protein after interacting with protein and are surrounded by these residues. DPPH and ABTS free radical scavenging assays demonstrated that the binding of WPI and Pte enhances the antioxidant capacity by more than fourfold compared to free Pte. This study provides insights into the interaction, modification, and development of novel polyphenol antioxidant systems, thereby effectively harnessing its physiological benefits.