Egg white protein-polyphenol-pullulan complexes: Structural characterization and application in high freeze-thaw...

High internal phase emulsions (HIPEs) are highly susceptible to structural deterioration during freeze-thaw cycles. In this study, egg white protein (EWP)-polyphenol-pullulan ternary complexes were constructed using proanthocyanidins (PC), gallic acid (GA), and tannic acid (TA) to enhance the freeze-thaw stability of HIPEs. SDS-PAGE and molecular docking analyses demonstrated synergistic covalent and noncovalent interactions between polyphenols and EWP. Formation of ternary complexes significantly reduced particle size (33.30-63.60%), increased surface charge density, and improved colloidal stability. A transition from spherical to lamellar microstructures and enhanced hydrophilicity were observed. HIPEs stabilized by the ternary complexes exhibited outstanding freeze-thaw stability (93.78-97.47%), while retaining high viscosity and well-developed rheological networks after cycling. Interfacial characterization revealed dense and rigid interfacial films, leading to smaller and more uniform droplets without phase separation. DSC analysis further confirmed superior freeze resistance through reduced crystallization temperatures. These results provide an effective strategy for designing freeze-stable HIPE systems.