Impact of ethanol extract of propolis on heat-induced egg white protein gels: Formation and properties.

The ethanol extracts of propolis-egg white protein (EEP-EWP) composite gels were prepared through thermal induction to investigate the impact of ethanol extract of propolis (EEP) addition on the physicochemical properties, structural characteristics, chemical forces and rheological properties of the composite gel. The results demonstrated that the composite gel containing 6% EEP exhibited a more compact and smooth microstructure, along with remarkable hardness (414.05 g) and water holding capacity (96.5%). Compared to the EWP gel, the hardness increased by 2.65 times and water holding capacity increased by 17.45%. Upon adding EEP, both energy storage modulus G′ and apparent viscosity initially increased before decreasing; β-sheet and β-turn content showed an initial increase followed by a decrease; however, α-helix and random coil content decreased initially before increasing again. Notably during gel formation, there was a significant increase in electrostatic interactions, hydrophobic groups, and disulfide bonds with subsequent decrease as EEP addition amounts increased (p < 0.05). This study expands the application range of propolis in novel gels while facilitating their development and utilization in low-fat or innovative functional products. [Display omitted] • Ethanol extract of propolis-egg white protein composite gel were prepared by thermal induction. • The composite gel with 6% ethanol extract of propolis had the best gel performance. • Ethanol extract of propolis can enhance electrostatic actions, hydrophobic bonds and disulfide bonds between egg white protein molecules. • Ethanolic extract of propolis can increase the β-sheets of egg white protein molecules while reducing random curls. [ABSTRACT FROM AUTHOR]