Ultrasound assisted complexation of soybean peptide aggregates and soluble soybean polysaccharide: pH optimization, structure characterization, and emulsifying behavior.

This study aims to enhance the emulsifying properties of soybean peptide aggregates (SPA) by preparing SPA-soluble soybean polysaccharide (SSPS) composite particles at the assistance of ultrasound technique. The optimal pH for SPA and SSPS complexation was determined by measuring the charge and particle size of the composites. The effects of ultrasound power and duration on the physicochemical properties of the composite particles were assessed through measurements of particle size, zeta potential, contact angle, FTIR, and SEM. The influence of ultrasound duration on the emulsifying properties of the composite particles was evaluated by particle size, zeta potential, microstructure, rheology, and in vitro digestibility. The optimal pH for SPA and SSPS complexation was determined to be 4.0. Zeta potential and FTIR analyses indicated that ultrasound enhanced the electrostatic interactions and hydrogen bonding between SPA and SSPS. Emulsions stabilized with ultrasonicated composite particles exhibited reduced particle sizes, increased viscosity, improved viscoelastic properties, and better in vitro digestibility. The results suggest that moderate ultrasound treatment can strengthen the interactions between SPA and SSPS, thereby enhancing their emulsifying properties. This study offers valuable insights into enhancing the emulsifying performance of highly hydrophobic protein particles.