Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2004
Publication Date: 1/20/2005
Citation: Losso, J.N., Khachatryan, A., Ogawa, M., Godber, S.J., Shih, F.F. 2004. Random centroid optimization of physphatidylglycerol stablized lutein-enriched oil-in-water emulsions at acidic pH. Food Chemistry. 0308-8146. Interpretive Summary: Age-related macular degeneration (AMD) is a pathological process that may cause the total loss of eye vision. There are few effective treatments for AMD. However, it is believed that nutritional intervention, using antioxidants and vitamins to enhance vision health may provide an effective way to prevent or treat AMD. Lutein is one of those antioxidants that may be considered as a conditionally essentially nutrient, if it provides clinical evidence of its effectiveness against AMD. To do that, lutein was combined with another bioactive compound, phosphatidylglycerol, to form an emulsion. The emulsion was found to have superior heat stability, and capable of providing protection against AMD.
Technical Abstract: Lutein has been identified by various studies as a dietary compound that may help delay the onset of macular degeneration. Random centroid optimization was applied to design, prepare, and characterize lutein-enriched oil-in-water (o/w) emulsions containing corn oil (15-25%), whey proteins (1.5-3.5%), phosphatidylglycerol (0.03-0.3%), KCl (80-100 mM), lutein (0.025-0.031%), and pH at 3.8-4.8. After nine experiments in the first random cycle and four experiments in the centroid cycle, optimal conditions for the preparation of stable lutein-enriched oil-in-water emulsion were: corn oil, 20%; whey proteins, 2%; phosphatidylglycerol, 0.157%; KCl, 93.7 mM; lutein, 0.0282%, and pH 4.55. The half-life stability, stability index, and zeta potential values for freshly prepared emulsions were higher when stabilized with phosphatdylglycerol than with phosphatidylcholine. Phosphatidycholine-stablized emulsions collapsed after heating at 90 oC for 5 min. Emulsion parameters for phosphatidylglycerol-stablized heated at 90 oC for 5 minutes, or stored at 4 oC for 24 h, were not significantly different from values obtained with freshly prepared emulsions. Lutein remained stable in fresh and heat-treated emulsions. The potential of phosphatidylglycerol and lutein as health enhancing bioactive compounds is discussed.