关键词: 大豆分离蛋白；大豆异黄酮；高压均质；结构性质；功能性质

Abstract: In order to find out the effect of high pressure homogenization on the interaction between soybean protein isolate (SPI) and soybean isoflavone (SI) and the functional properties of their complexes and to determine the best treatment conditions, complexation between 10 mg/mL SPI and 0, 0.2 or 2 mg/mL SI was triggered using different homogenization pressures. The conformational differences among the resulting composites were analyzed by ultraviolet spectroscopy (UVS), fluorescence spectroscopy (FS) and Fourier transform infrared spectroscopy (FTIR). Their hydrodynamic radius and functional properties were characterized by their particle size, zeta potential, solubility and hydrophobicity. The results showed that the fluorescence quenching of SPI by SI was static as evaluated by FTIR. When the pressure was 80 MPa and the SI concentration was 0.2 mg/mL, the particle size distribution was stable, and the absolute value of zeta potential, solubility, and hydrophobicity were remarkably improved (P < 0.05). UVS and FTIR indicated that the microenvironment near tryptophan residues in SPI was more hydrophilic and the secondary structure of SPI was changed.

Key words: soybean protein isolate; soybean isoflavone; high pressure homogenization; structural properties; functional properties