Resveratrol promotes interfacial adsorption behaviour and retards protein-lipid co-oxidation of whey protein isolate stabilised O/W emulsions

Abstract

Resveratrol, a non-flavonoid polyphenol found mainly in red grapes and peanuts, with excellent antioxidant and protein-binding properties. This present work was aimed to systematically investigate the effects and mechanism of incorporation of different levels (0, 0.2, 0.4, 0.8, and 2.0 mM) of resveratrol on the interfacial adsorption behaviour and protein-lipid co-oxidation of whey protein isolate (WPI)-stabilised oil-in-water (O/W) emulsions. The results showed that the physical stability of the O/W emulsion was gradually enhanced with increasing resveratrol levels, which was clearly evidenced by increasing absolute ζ-potential values and decreasing droplet size. Moreover, the content of adsorbed proteins (AP) slightly increased as a function of resveratrol level, which evidenced that resveratrol could effectively modulate the interfacial adsorption behaviour of WPI in O/W emulsions. Meanwhile, molecular docking simulation showed that the resveratrol could bind to WPI through hydrogen bonding and hydrophobic interaction. Compared to unadsorbed proteins (UAP), the structural characteristics and molecular mass of AP were more affected by resveratrol, which was confirmed and characterised by electrophoresis and fluorescence. Furthermore, incorporation of resveratrol only retarded, but did not completely inhibit, protein-lipid co-oxidation of O/W emulsions under an accelerated oxidation condition, as demonstrated by oxidation stability, hierarchical cluster, and correlation analysis. Our results clearly demonstrated that the resveratrol could modulate the interfacial adsorption of WPI and retard the protein-lipid co-oxidation of WPI-stabilised O/W emulsions with enhanced storability, further broadening the application of resveratrol in the food industry.