Lutein-Enriched Emulsion-Based Delivery System: Impact of Casein-Phospholipid Emulsifiers on Chemical Stability

The health benefits of carotenoids in terms of their role in decreasing the risk of diseases, particularly certain cancers and eye disease, are limited by their chemical degradation. Emulsion delivery systems with water dispersions of a carotenoid enhance chemical stability and bioavailability to the host. An emulsified carotenoid delivery system can be based on carotenoid dissolution in lipid media and its stabilization by a surfactant mixture of milk proteins (the caseins) and phospholipids. The inclusion of lutein into an emulsified delivery system comprised of bovine casein or caprine casein in combination with phospholipids (soybean lecithin) enhanced the chemical stability of lutein during storage for 7 days at pH 7.0 at incubation temperatures of 5 and 15°C. The chemical stability of lutein in the corn oil-in-water emulsions stabilized by bovine and caprine caseins in combination with soybean lecithin was in the following order: caprine αs1-II-casein/lecithin > caprine αs1-I-casein/lecithin > bovine casein/lecithin. The results suggest that the chemical stability of lutein in oil-in-water emulsions can be enhanced by altering the thickness of the interfacial layer. Caprine casein/lecithin has the potential for use as an emulsifier in beverage emulsions