Enhanced thermal stability of liquid egg white via disrupting the double-network structure at the initial stage of...

Liquid egg white (EW) is highly susceptible to heat-induced denaturation and coagulation, which limits pasteurization conditions in the egg processing industry. This study investigated ultrasound-alkali pretreatment for controlling protein aggregation and gelation during the initial gelation stage (56-72 °C). Compared to untreated EW, the ultrasound-alkali pretreated EW exhibited significantly reduced turbidity and viscosity upon heating, while maintaining high fluidity and transparency even at 72 °C. Soluble protein content increased almost three times. Rheological and SDS-PAGE results revealed that untreated EW forms a double-network gel structure primally composed of ovomucin, ovotransferrin, and lysozyme during the initial gelation stage. Cryo-SEM and AFM images confirmed that ultrasound-alkali pretreatment disrupted this interpenetrating network structure, thereby improving colloidal particle dispersion. Additionally, FT-IR and LF-NMR results indicated that the pretreatment partially protected protein structure from heat-induced damage while increasing free water mobility. The results of this study provide a new strategy for enhancing the thermostability of liquid EW and increasing the pasteurization condition of egg products in the food industry.