Structure-function modulation of sodium caseinate: Insights from non-covalent reuterin binding.

This study investigated the effects of varying concentrations of reuterin (3-hydroxypropionaldehyde, 3-HPA) on the structural and functional properties of sodium caseinate (SC). UV spectroscopy and SDS-PAGE analysis demonstrated the formation of SC/3-HPA complexes through non-covalent binding. Fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy showed that 3-HPA induced significant conformational changes in SC (P < 0.05). Furthermore, significant decreases were observed in the content of sulfhydryl groups and free amino groups, accompanied by modified surface hydrophobicity. Computational simulations predicted hydrogen bonding and hydrophobic interactions as the predominant driving forces for SC/3-HPA complexation. Scanning electron microscopy, combined with particle-size analyses, revealed a significant reduction in average particle diameter and improved surface smoothness of the complexes. Notably, 3-HPA treatment improved the solubility, emulsifying activity, and foaming property of SC. These findings highlight the potential of 3-HPA as a novel non-covalent molecular modulator for regulating the structural and functional properties of sodium caseinate.