Comparison of the physical stability, microstructure and protein-lipid co-oxidation of O/W emulsions stabilized by L-arginine/L-lysine-modified soy protein hydrolysate

This work investigated the physical stability, microstructure, and oxidative stability of the emulsions prepared by soy protein hydrolysate (SPH) after modification with different concentrations of L-arginine and L-lysine. LArginine and L-lysine significantly increased the absolute zeta potential values, and decreased droplet sizes of the emulsions, thereby improving the physical stability of the emulsions. Meanwhile, L-arginine and L-lysine markedly decreased the apparent viscosity of the emulsions. The measurement of interfacial protein adsorption percentage showed that L-arginine (<= 0.5 %) promoted the adsorption of SPH at the oil-water interface, whereas L-lysine (<= 1%) reduced the adsorption of SPH at the oil-water interface. In addition, L-arginine and L-lysine (<= 0.5 %) could retard lipid and protein oxidation. Correlation analysis indicated that the improvement in the physical stability of the emulsions by L-arginine and L-lysine also enhanced the oxidative stability of the emulsions. In summary, L-arginine and L-lysine could be effective modifiers for the protein-based emulsion systems.