Enhanced physicochemical stability of lutein-enriched emulsions by polyphenol-protein-polysaccharide conjugates and fat-soluble antioxidant

This study aimed to design a lutein-enriched emulsion with improved physical and chemical stability. Ternary conjugates covalently fabricated using bovine serum albumin (BSA), chlorogenic acid (CA) and dextran (DEX) were used as novel emulsifiers, and vitamin E (VE) was used as a fat-soluble antioxidant. The conjugates were characterized using SDS-PAGE, fluorescence spectroscopy and Fourier transform infrared spectroscopy (FTIR). Further, o-Phthalaldehyde (OPA) assay indicated that the conjugation efficiency was 13.4% and 16.5% for CA-BSA-DEX conjugates and BSA-DEX conjugates, respectively. The characteristics of emulsions stabilized by different emulsifiers were studied under different environmental stress, pH and temperature conditions. The results showed that ternary conjugates can be effectively used to prepare emulsions with improved physical stability around the isoelectric point (IEP) compared with protein alone, and the addition of VE can effectively improve the chemical stability of lutein-enriched emulsions without affecting their physical stability. In addition, a simulated gastrointestinal tract (GIT) showed that compared with the others, VE group had a relatively higher bioaccessibility (64.5%).