Sodium caseinate-Sucrose ester based delivery system for carotenoids from Lycium barbarum L:Fabrication,characterization and formation mechanism of high internal phase emulsions

High internal phase emulsions (HIPEs) enriched with carotenoids were prepared using one-step shearing method, with the assistance of sodium casein(SC)- sucrose esters(SE), to further improve the stability of natural carotenoids. We investigated the properties of HIPEs with diverse SC-SE concentrations and ratios. Results indicated that the combination of SC-SE concentrations at 10% and 12.5% and ratios at 1:1 and 2:1 shows significant improvements in HIPEs stability. Notably, the stable network structure was formed in the HIPEs system by increasing electrostatic interactions and hydrogen bonds between SC and SE. Observations using Cryo-SEM further showed that the oil droplets in HIPEs were spaced apart by a dense three-dimensional mesh structure, and uniform filamentous protrusions were formed on the surface of oil droplets. HIPEs exhibited ideal cold storage and heat resistance, and the retention rates of zeaxanthetin dipalmitate (ZDP) were 95.48% and 78.60% respectively, after being heated at 100ºC for 3 cycles and exposed to ultraviolet light at 4ºC for 28 days. In vitro digestion results showed ZDP in the system had good slow-release performance. This could provide a new perspective for developing delivery systems for fat-soluble active ingredients requiring slow-release performance or functional foods with satiety.