Effect of High-pressure Homogenization on Structure and Properties of Soy Protein Isolate/polyphenol Complexes

Understanding the effects of typical unit operations on the structure and properties of protein/polyphenol complexes has important guiding value for the design and development of two-component functional foods. Therefore, the effects of high-pressure homogenization (HPH) on the structure, physicochemical properties, and in vitro digestive characteristics of soy protein isolate (SPI)-black soybean coat extract (BE) complexes were investigated. UV-Vis and intrinsic fluorescence spectra manifested that the tertiary conformation of protein was partially unfolded after HPH treatment. In addition, with the enhancement of HPH pressure, the zeta-potential magnitude and average particle size of SPI-BE complexes increased and decreased, respectively. On the other hand, HPH had no significant effect on in vitro digestion, anthocyanin content, and free radical scavenging ability of SPI-BE complexes. These findings can provide new insights and guidance for the optimization and regulation of protein-polyphenol co-existing food systems, and provide reference for their application in food industry.