Comparison in structure, physicochemical and emulsifying properties of alpha lactoglobulin and beta lactalbumin exposed to prior γ-oryzanol by the multi-spectroscopic and silico methods

In this work, effects of γ-oryzanol (GO) on structure, physicochemical and emulsifying properties of α-lactalbumin (α-La) and β-lactoglobulin (β-Lg) were compared by using multi-spectroscopic analysis and computer simulation. Specifically, the intrinsic fluorescence of both whey proteins was quenched by GO, with GO being a stronger quenching for β-Lg than for α-La. The addition of GO caused the backbone of α-La to become denser, whereas for β-Lg, its spatial structure shifted from ordered to disordered after the addition of GO. Additionally, the surface hydrophobicity, emulsifying properties, and DPPH free radical scavenging capacity of β-Lg were higher than α-La after the addition of GO. Molecular docking indicated that the primary driving force in the whey protein-GO system was hydrophobic force. The hydrophobic pocket at the cleft between two structural domains in β-Lg and α-La was the binding area for GO, and GO had greater binding affinity for β-Lg than α-La. Furthermore, molecular dynamics simulations demonstrated that β-Lg-GO system was more stabilized than α-La-GO system. This research contributed to a deeper understanding of the mechanisms by which α-La and β-Lg interact with GO, offering the potential to develop whey protein-GO complexes as novel emulsifiers.