Molecular insights into β-cyclodextrin-induced structural reorganization and functional enhancement of soybean protein isolate

This study investigated the interactions between soybean protein isolate (SPI) and β-cyclodextrin (β-CD), focusing on structural changes and functional enhancements. Results revealed that β-CD induces SPI conformational changes by decreasing α-helix, increasing β-structures, and enhancing flexibility via non-covalent interactions. Redshift in the negative peak from 203 to 214 nm as β-CD concentration increased from 0.1 to 1.0 mg/mL. Fluorescence quenching confirmed spontaneous complexation driven by hydrophobic forces. Moderate β-CD concentrations improved the functional and interfacial properties of SPI, whereas higher levels promoted aggregation and diminished performance. Increasing β-CD concentration elevated SPI-β-CD particle size from 197.6 to 310.7 nm and zeta potential from −15.52 to −24.27 mV. SEM confirmed structural rearrangement without compromising material integrity, while molecular docking showed stable complex formation through hydrogen bonding and van der Waals forces. These findings highlight the potential of SPI-β-CD complexes for enhanced functionality in emulsions, delivery systems, and various applications.