Effect of emulsifier composition on oil-in-water nano-emulsions: Fabrication, structural characterization and delivery of zeaxanthin dipalmitate from Lycium barbarum L.

A nano-emulsion enriched with zeaxanthin dipalmitate (ZDP) was prepared by high-pressure homogenisation to improve the bioavailability of ZDP in Lycium barbarum L. The visual differences, rheology and microstructure of the emulsion were evaluated, which indicated that sodium caseinate (SC), SC/sucrose esters (SE) and SC/octyl succinic anhydride (OSA) modified starch have excellent emulsifying effect. The Fourier transform infrared spectroscopy (FTIR) results revealed that hydrogen bonding and hydrophobic interactions were involved in the formation of ZDP nanocomplexes. The SC/SE-fabricated nano-emulsion achieved the smallest particle size of 152.2 nm and highest ZDP encapsulation efficiency (EE) of 90.65%. The EE of ZDP in the nano-emulsion minor changed with pH, light and heat conditions, except at pH 2.5. The in vitro ZDP release rate in the delivery system was (67.5%) was significantly higher than goji puree (26.6%). These findings may have important implications in designing emulsion systems with improved release rates of lipid-soluble carotenoids.