Effect of heat treatment on physicochemical, interfacial, and encapsulation properties of pea and soy protein-based emulsions and their spray-dried powders.

Plant proteins are promising alternatives to animal proteins but often show limited emulsion stability after heat treatment. This study evaluated the impact of mild (65 °C) and moderate (85 °C) heating on pea protein concentrate and soy protein isolate emulsions containing sunflower oil, followed by spray-drying. Moderate heating reduced particle size and enhanced zeta potential, protein solubility, and emulsion stability over mild heating. SPI-stabilized emulsions showed higher protein-fat interfacial adsorption and better encapsulation efficiency (94.38 % for S85 vs 82.06 % for P85). Spray-dried powders from moderately heated emulsions exhibited lower sedimentation and retained key physicochemical properties such as smaller particle size, higher zeta potential, and improved encapsulation efficiency. SDS-PAGE revealed differences in protein subunit distribution in the cream phase, indicating altered interfacial protein composition due to heat treatment. These results indicate that moderate heating enhances plant protein functionality, enabling effective encapsulation of oxidation-prone oils into stable, protein-rich powders for food use.