Effect of High-Pressure Processing on the Physicochemical and Emulsifying Properties of Pea Protein Isolate

This study investigated the effects of high-pressure processing (HPP) on the physicochemical and functional properties of pea protein isolate (PPI). PPI was HPP-treated at 0.1 (control), 400, and 500 MPa, and its protein solubility, oil-holding capacity (OHC), surface hydrophobicity (H₀), ζ-potential, and emulsion droplet size (D_4,3) were evaluated. Results showed that HPP significantly improved protein solubility, reaching 38.61% at 400 MPa compared with 12.45% in the untreated PPI powder. OHC and H₀ of PPI also increased after HPP, suggesting its enhanced interaction with oil and exposure of hydrophobic residues. Emulsions stabilized with HPP-treated PPI exhibited smaller droplet sizes and higher absolute ζ-potential values, suggesting improved initial emulsifying properties. The enhancement in functional properties may be associated with changes in surface hydrophobicity and charge characteristics, potentially reflecting pressure-induced conformational rearrangements. However, a slight decrease in solubility and surface hydrophobicity was observed at 500 MPa, which may be associated with pressure-induced protein aggregation. Overall, HPP effectively modified PPI surface characteristics, leading to improved emulsifying and functional performance, highlighting its potential application in food formulations requiring good protein dispersibility and emulsifying properties.