Effects of Ultra-high Pressure Treatment on the Physicochemical Properties of Pea Protein

This study investigated pea protein subjected to different intensities of ultrahigh pressure (100 MPa for 15 min, 300 MPa for 15 min, and 600 MPa for 15 min) and analyzed the changes in its physicochemical properties, including solubility, subunit composition, particle size and zeta potential, secondary structure, microstructure, and total thiol content, to enhance its quality and expand its application range. Results indicated that in contrast to the control treatment, the 100 MPa ultrahigh-pressure treatment altered the spatial conformation of pea protein, reducing the molecular particle size of pea protein from 176.83 nm to 143.37 nm. The pea protein solution exhibited decreased viscosity and increased hydrophilicity, and no significant changes in its solubility, zeta potential, or total thiol content were observed. Solution stability improved, whereas subunit composition distribution remained unchanged, and the protein did not undergo complete denaturation. After treatment at 300 and 600 MPa, the surface charge distribution of the protein changed, reducing electrostatic repulsion and increasing the aggregation of protein molecules, leading to an increase in particle size. Nevertheless, the particle sizes of the samples treated at 300 and 600 MPa remained smaller than that of the control sample. The protein solution showed increased viscosity and enhanced hydrophobicity, and its solubility decreased to 74.59% and 56.03%. Absolute zeta potential significantly decreased, the order of the secondary structure of the protein increased, aggregation intensified, solution stability decreased, and total thiol content significantly decreased, resulting in partial protein denaturation. In conclusion, the structure and physicochemical properties of pea protein vary depending on the hydrostatic pressure applied. This study aims to provide a reference for the application of pea protein in food processing.