Characterization and utilization of soy protein isolate-(-)-epigallocatechin gallate-maltose ternary conjugate as an emulsifier for nanoemulsions: Enhanced physicochemical stability of the ß-carotene nanoemulsion.

In this study, a ternary conjugate was prepared by covalent bonding of protein, polysaccharide, and polyphenol via ultrasound and the Maillard reaction. Subsequently, the ß-carotene nanoemulsion was prepared with the soy protein isolate-(-)-epigallocatechin gallate-maltose (SPI-EGCG-maltose) conjugate as the emulsifiers via ultrasound. The SPI-EGCG-maltose conjugate showed superior solubility, emulsification and foaming properties at 4 h reaction time. Meanwhile, the retention rates of ß-carotene in the nanoemulsion after 30 d of storage, 8 h of light, and 55 °C of heat were >60%, >75%, and >60%, respectively. Furthermore, ultrasound treatment at 500 W for 10 min produced an inhibitory effect on the degradation of ß-carotene. This study indicates that the nanoemulsion based on the ternary conjugate can effectively inhibit the ß-carotene degradation by the external environment and prevent the oxidation and degradation of ß-carotene in the nanoemulsion.