Complexation of resveratrol with soy protein and its improvement on oxidative stability of corn oil/water emulsions

This work was to evaluate the potential of soy protein isolate (SPI)-resveratrol (RES) complex as an emulsifier to improve the effectiveness of RES as a natural antioxidant in corn oil-in-water emulsions. The physical properties and oxidative stability of emulsions stabilized by the native SPI-RES and heated SPI-RES complexes were evaluated. The water solubility of RES was enhanced by complexation with SPI, which was mainly driven by hydrophobic interactions. Heat treatment favoured the formation of the SPI-RES complex and endowed it with a higher antioxidant activity. Furthermore, the emulsions stabilized by the SPI-RES complexes showed an increased oxidative stability with reduced lipid hydroperoxides and volatile hexanal. This improving effect could be attributed to the targeted accumulation of RES at the oil-water interface accompanied by the adsorption of SPI, as evidenced by the high interfacial RES concentration. These findings show that the soy protein-polyphenol complex exhibited a good potential to act as an efficient emulsifier to improve the oxidative stability of emulsions.