Insight into the Stabilization Mechanism of Rice Protein Amyloid Fibrils Modification on Soy Protein Gels: Gel Properties, Microstructure, and Molecular Conformation

Abstract

The objective of this work was to investigate the effects of rice protein amyloid fibrils (RF) on gel and structural properties of soy protein isolate (SPI) gel. The addition of RF (3%~10%) increased the gel hardness (33.17 g to 74.43 g), thermal stability, viscoelastic properties and microstructure of SPI gel to some extent, whereas the 15% RF was harmful to these gel properties of SPI gel. Fourier-transform infrared and X-ray diffraction results suggested that RF mainly interacted with SPI through non-covalent interaction, which decreased the proportion of α-helix and increased the β-sheet content of SPI. Molecular interactions indicated that hydrogen bonds and hydrophobic interaction was the main driving force for binding of RF and SPI, and the strength of the non-covalent interaction was determined by the RF content. These findings contributed to the development and manufacturing of SPI gel, as well as enhanced the added value of rice protein.

Keywords: Amyloid fibrils, Rice protein, Gel properties, Soy protein isolate, Microstructure