Effects of thermal aggregation treatment on the structural, gelation properties and microstructure of phosphorylated rice glutelin gel

The effects of thermal aggregation treatment on the structural, gelation properties and microstructure of phosphorylated rice glutelin (PPRG) gels were investigated. The phosphorylation modification considerably improved the viscoelasticity of the rice glutelin (RG) gel (the final G ' and G '' values increased from 2.91, 0.38 Pa to 380.76, 82.25 Pa, respectively), as well as gel strength (from 137.0 N to 194.6 N) and water holding capacity (from 82.6% to 99.3%). The electrophoresis results showed that the proteins in the gel formed by thermal aggregation were more degraded, indicating that more interactions occurred in the protein molecules. The main molecular forces involved in RG gels were hydrophobic interactions and disulfide bonds. The thermal aggregation treatment increased the beta-sheet content and decreased the alpha-helix content of the RG gels. The microstructure results suggested that the gel formed by thermal aggregation had a more interactive and denser network structure, while the gel structure formed by direct heating was coarser. These results provide some valuable information for improving the properties and applications of low water-soluble protein gels.