Construction and characterization of a ternary composite emulsion based on hydrolyzed soy protein isolate

Achieving long-term stability of oil-in-water emulsions through robust interfacial films remains challenging. This study aimed to address this challenge by using hydrolyzed soy protein isolate-tannic acid-citrus pectin (HSPI-TA-CP) ternary complexes as stabilizers and investigating the effects of complex concentration (1%-3%, w/w) on emulsion microstructure and physicochemical properties. The complexes adsorbed at the oil-water interface via hydrogen bonding and electrostatic interactions, forming a dense interfacial film. As the concentration increased from 1% to 3%, the droplet size significantly decreased from 24.87 to 12.27 μm, the zeta potential shifted from -40.65 to -57.91 mV, and the emulsion stability index increased from 52.23% to 91.47%. All emulsions exhibited a strong gel network structure (G' > G″). At 2.5% concentration, interfacial adsorption approached saturation, and the emulsions showed optimal storage stability and good pH and temperature tolerance. This study demonstrates the effectiveness of HSPI-TA-CP ternary complexes as emulsion stabilizers.