Abstract: This study aimed to explore the binding mechanism of soybean β-conglycinin (7S)/glycinin (11S) with baicalein, and to investigate the changes in the conformational and functional properties of the complexes. Fourier transform infrared (FT-IR) spectroscopy indicated that baicalein could induce the transformation of β-sheets into α-helices and random coils. Intrinsic fluorescence spectra confirmed that the addition of baicalein made the structure of 7S and 11S more compact. The reaction of baicalein with the proteins took place spontaneously and quenched the protein fluorescence in a static manner. The 7S and 11S proteins bound to baicalein by hydrogen bonds and hydrophobic interactions, respectively. Molecular docking results showed that the affinity of baicalein to 11S was higher than that to 7S. Scanning electron microscopy (SEM) showed microstructure differences between 7S and 11S and their complexes. In addition, the surface hydrophobicity of 7S and 11S was decreased and the functional properties such as thermal stability were improved after combining with baicalein.

Key words: β-conglycinin (7S); glycinin (11S); baicalein; binding mechanism; conformational change; functional properties