Soybean isolate protein complexes with different concentrations of inulin by ultrasound treatment: Structural and functional properties

Ultrason Sonochem. 2024 Mar 30;105:106864. doi: 10.1016/j.ultsonch.2024.106864. Online ahead of print.ABSTRACTThe effects of ultrasound and different inulin (INU) concentrations (0, 10, 20, 30, and 40 mg/mL) on the structural and functional properties of soybean isolate protein (SPI)-INU complexes were hereby investigated. Fourier transform infrared spectroscopy showed that SPI was bound to INU via hydrogen bonding. All samples showed a decreasing and then increasing trend of α-helix content with increasing INU concentration. SPI-INU complexes by ultrasound with an INU concentration of 20 mg/mL (U-2) had the lowest content of α-helix, the highest content of random coils and the greatest flexibility, indicating the proteins were most tightly bound to INU in U-2. Both UV spectroscopy and intrinsic fluorescence spectroscopy indicated that it was hydrophobic interactions between INU and SPI. The addition of INU prevented the exposure of tryptophan and tyrosine residues to form a more compact tertiary structure compared to SPI alone, and ultrasound caused further unfolding of the structure of SPI. This indicated that the combined effect of ultrasound and INU concentration significantly altered the tertiary structure of SPI. SDS-PAGE and Native-PAGE displayed the formation of complexes through non-covalent interactions between SPI and INU. The ζ-potential and particle size of U-2 were minimized to as low as -34.94 mV and 110 nm, respectively. Additionally, the flexibility, free ...

Source: Ultrasonics Sonochemistry - April 6, 2024 Category: Chemistry Authors: Mengmeng Wang Sai Yang Na Sun Tingting Zhu Ziteng Lian Shicheng Dai Jing Xu Xiaohong Tong Huan Wang Lianzhou Jiang Source Type: research