Enhancing structural and functional characteristics of broken rice protein through pulsed electric field-assisted alkaline treatment

This study investigated the effects of pulsed electric field (PEF) parameters, including pulse intensity (25–35 kV/cm), pulse width (50–200 µs), and pulse stop time (50–100 ms), on the structural and functional properties of rice protein. Using response surface methodology (RSM), the optimal PEF conditions were identified as 35 kV/cm pulse intensity, 197.226 µs pulse width, and 59.675 ms pulse stop time. Under these conditions, the PEF-treated sample was compared with an untreated control to assess structural and functional modifications. PEF treatment disrupted the secondary (FTIR) and tertiary (UV-Vis, fluorescence) protein structures, leading to the exposure of hydrophobic groups and enhancing protein flexibility (36.04 to 52.575%) and surface hydrophobicity (24.39 ± 0.47 to 27.45 ± 0.37). Total (6.453 to 7.525 µmol/g) and exposed sulfhydryl content (3.752 to 6.511 µmol/g) increased significantly (p < 0.05), while disulfide bonds decreased (34.828 to 22.626 µmol/g). A slight increase in non-protein nitrogen (5.66 to 6.71 µg/mL) content was also observed. Functional properties, including protein digestibility (9.2%), DPPH assay (20.34%), and emulsification, were significantly improved (p < 0.05) compared to the control. These results demonstrate that PEF treatment effectively modifies rice protein’s structure and enhances its functional properties for potential applications in functional foods. PFE treatment employed for protein modification using BBD. SS bonds reduced by 35% and increased SH and surface hydrophobicity of BRP. Protein digestibility improved by ~9.2% compared to the control sample. PEF significantly (p<0.05) improved the emulsion, flexibility, and scavenging activity of BRP.