Propylene glycol alginate (PGA)-modulated interfacial assembly of dual-protein nanoparticles for stabilizing Pickering emulsions in ethanol-water system.

Stabilizing protein-based emulsions in ethanol-containing systems remains challenging due to ethanol-induced protein denaturation and instability. This study investigated the interfacial assembly of lactoferrin-zein (LZ) dual-protein nanoparticles by propylene glycol alginate (PGA) in the 15 % (v/v) ethanol-water system. As the PGA level increased, the ζ-potential of the composite nanoparticles shifted from positive to negative values, reaching a maximum absolute value of 40.8 ± 1.9 mV at LZ-PGA1:2. Simultaneously, surface hydrophobicity (H₀) decreased from 9987.6 ± 101.1 (LZ control) to 2198.0 ± 46.5 (LZ-PGA1:3), suggesting reduced ANS accessibility due to steric hindrance. Optimal emulsifying performance was observed at LZ-PGA1:2, with the emulsifying activity index reaching 33.55 ± 0.70 m2/g, interfacial tension decreasing to 17.69 ± 0.17 mN/m, and droplet size reduced to 10.28 ± 1.54 μm. Furthermore, the consistency index of the emulsions increased markedly from 13.74 ± 0.69 to 39.98 ± 2.23 Pa·sn, while Turbiscan stability index value declined, indicating enhanced viscoelasticity and physical stability. Interfacial microstructures displayed improved film continuity, thickness, and network formation. These findings demonstrate the potential of PGA-modulated interfacial assembly to improve the ethanol tolerance and functional performance of Pickering emulsions in alcohol-based beverage applications.