Investigating the stability and mechanism of a walnut protein isolate-ovalbumin dual-protein emulsion system:...

Ovalbumin (OVA)-stabilized emulsions often suffer from coalescence-prone nature due to the protein's rigid structure and insufficient surface hydrophobicity. To overcome these limitations through synergistic stabilization. This study systematically investigated the interfacial behavior and emulsion stability of a walnut protein isolate (WPI)-OVA system (ratios 0:10 to 10:0) and employing multiscale characterization. Results demonstrated that WPI and OVA formed a dense interfacial film via hydrophobic interactions and electrostatic attraction. While the 7:3 ratio exhibited higher rigidity, the 9:1 ratio achieved the optimal viscoelastic balance for stability, with dilatational and elastic moduli of 46.75 mN/m and 46.68 mN/m, respectively, effectively suppressing droplet aggregation. Concurrently, increasing the WPI proportion effectively restored the emulsion's zeta potential to -37.9 mV (close to that of pure OVA), thereby strengthening electrostatic repulsion and further improving stability. This work elucidates a triple synergistic stabilization mechanism for WPI-OVA complexes at the oil-water interface, encompassing interfacial film reinforcement, steric hindrance, and electrostatic stabilization, thus offering a novel paradigm for designing plant/animal protein hybrid systems.