The addition of oxidized tea polyphenols enhances the physical and oxidative stability of rice bran protein hydrolysate-stabilized oil-in-water emulsions

This study investigated the effects of rice bran protein hydrolysate (RBPH) coupled with oxidized tea polyphenols (OTP) on the physical and oxidative stability of oil-in-water emulsions. Emulsions stabilized with RBPH alone were less stable than those stabilized with both RBPH and OTP. The OTP not only improved the emulsification stability, flocculation stability, coagulation stability, and ζ-potential of the emulsions, OTP also decreased the particle size, increased the adsorption capacity of the oil–water interface for RBPH, and effectively reduced the generation of peroxide and malondialdehyde in the emulsion during storage. The stability of the emulsion during the early stage of storage was maximized when the OTP content was 1.5%; at greater contents, the OTP competed with RBPH for adsorption at the interface, which affected the distribution of RBPH on the interface and decreased the emulsion stability. The results indicate that OTP can enhance emulsion stability, providing a reference for the application of oxidized polyphenols in food emulsions.