Exploring molecular interactions between oleic acid and whey protein: implications for emulsification and functional properties in modern food systems by multi-technique approach

This study investigated the interaction mechanism between Oleic acid (OA) and β-lactoglobulin (β-LG) using various biophysical techniques. UV–visible (UV–vis) spectroscopy confirmed the formation of β-LG -(OA) complexes, consistent with fluorescence data. The intrinsic fluorescence investigations showed that the quenching mechanism was static, with a decreased fluorescence quenching constant as temperatures increased. Thermodynamic parameters (ΔH < 0; ΔS < 0) confirmed the formation of a complex between OA and β-LG through hydrogen and van der Waals interactions. The interaction with OA also led to changes in the secondary structure of β-LG, as observed through FTIR and CD, which showed a transition from β-structures to α-helix. Molecular docking analysis revealed the involvement of specific residues in the binding between β-LG and OA, with a docking energy of −24.39 kJ/mol, suggesting a spontaneous interaction with moderate to high affinity. The increases in RMSD, RG were observed for the β-LG -the results of thermal stability supported (OA) complex. The findings from this study provide new insights into the interaction mechanism between β-LG and OA. The results indicate that β-LG can serve as a delivery vehicle for OA in functional food applications.