Mechanistic study on the decline of foaming characteristics of egg white under heat stress: Emphasizing apparent phenomena, structure, and intermolecular interactions.

Heat stress is a critical step in the processing of liquid egg white; however, this treatment can severely affect its foaming properties. This study aims to elucidate the mechanisms underlying the decline in foaming properties of liquid egg white during heat stress. The research begins by examining the adverse effects of heat stress on the foaming properties of liquid egg whites, where an increase in apparent viscosity, turbidity, and particle size is initially observed, indicating the formation of aggregates. After heat stress, the binding water capacity of the liquid egg white increases, intermolecular forces strengthen, and the secondary structure transforms towards β-sheet and β-turn configurations, while surface hydrophobicity decreases. Heat stress promotes the transition of liquid egg white into a more stable gel state. Additionally, electrophoresis results show the disappearance of bands for ovomucin subunit, ovotransferrin, and lysozyme, while microscopic observations reveal a rougher surface texture of the samples. In summary, this study provides insights and theoretical basis for understanding the mechanisms behind the decline in foaming properties of liquid egg whites under heat stress.