Boosting foam ferformance of egg white protein: synergy between supercritical carbon dioxide and sucrose for superior freeze-thaw stability

This study investigated the synergistic effects of supercritical carbon dioxide (SCCD) combined with sucrose treatment on the foaming properties and freeze-thaw stability of egg white protein (EWP). The results demonstrated that SCCD-sucrose treatment significantly enhanced the foaming capacity, achieving a maximum of 139.5% (4.6-fold increase over the control) at 9 MPa for 60 min with 10 g/100 mL sucrose, while maintaining the foaming stability (FS) which was compromised by SCCD treatment alone. Furthermore, the treated EWP exhibited markedly improved stability against repeated freeze-thaw cycles. Mechanism analysis revealed that sucrose promoted the formation of larger protein aggregates, as evidenced by increased particle size, and significantly reduced surface tension, enhancing adsorption at the air-water interface. Fourier transform infrared spectroscopy indicated a rise in α-helix relative content, contributing to structural ordering, while rheological measurements showed improved elastic modulus (G′), supporting FS. Scanning electron microscopy further revealed a more cohesive and dense protein network of SCCD-sucrose treated group. These synergistic modifications counteracted the structural loosening induced by SCCD and facilitated the formation of a robust interfacial film. The findings provide an effective and promising physical modification strategy for enhancing the functional performance of frozen-stored egg white liquid in the egg processing industry.