Effect of high hydrostatic pressure on the structure, physicochemical properties and functional properties of rice bran protein: An integrated experimental study.

Rice bran protein (RBP) is a high-quality plant protein derived from rice bran (RB), a by-product of rice processing. However, its broader utilization is constrained by suboptimal functionality and structural characteristics. This study systematically evaluated the effects of high hydrostatic pressure (HHP) treatment and HHP-assisted extraction on the structural, physicochemical, functional, and antioxidant properties of RBP. HHP treatment and HHP-assisted extraction improved protein solubility, foaming capacity, water-holding capacity, and oil-holding capacity. Multiscale structural characterization indicated that both processes induced protein unfolding. They also promoted β-sheets formation, with maximum increases of 8.11% and 23.15%, respectively, and modified the tertiary structure. In addition, antioxidant assays showed that ABTS radical-scavenging activity increased by up to 39.71%, while the FRAP value increased 3.80-fold. These findings support that HHP treatment and HHP-assisted extraction drive structural changes in RBP and enhance its functional performance. Overall, as a non-thermal processing approach, HHP can modify RB and RBP and broaden their potential applications in the food industry.