Abstract:This study aimed to investigate the gel properties of whey protein cold-set emulsion gel as influenced by interaction of different concentrations (2.7, 13.3, 26.6 μmol phenolic/g protein) of epigallocatechin gallate (EGCG) with the protein. The particle size, zeta potential and interfacial protein adsorption were measured by dynamic light scattering and automatic Kjeldahl nitrogen determination, respectively. The microstructure of the emulsion was observed by laser scanning confocal microscope. The gel strength was measured by the texture analyzer, and the force in the gel was evaluated by the difference of the solubility of the emulsion gel in four solutions. Scanning electron microscope was used to analyze the microstructure of the emulsion gel. The results showed that with the treatment of EGCG, the protein emulsion exhibited smaller average particle size, increased electrostatic repulsion between the emulsion droplets, and more uniform distribution of the particle size. Moreover, with the interaction of EGCG and protein, the microstructure of the corresponding cold-set emulsion gel was more uniform, smoother and closely connected, as well as the gel strength was enhanced. With EGCG at high concentration, the average particle size of emulsion was the smallest (~385 nm); the electrostatic repulsion between emulsion droplets was the largest; the hydrophobic force and electrostatic force in the emulsion gel were the strongest, and a 92.6% increase in gel strength when compared with the control.