The objective of this study was to determine the effect of caprine casein in combination with arabinogalactan on the chemical stability of lutein in corn oil-in-water emulsion at 25oC for 96 hours.  Previous studies have reported an increase in the chemical stability of lutein-loaded oil-in-water emulsions prepared using bovine casein.  However, the chemical degradation of lutein in corn oil-in-water emulsions stabilized by bovine casein increased with increasing temperature from 5 to 70 oC.  The concentration of lutein in oil-in-water emulsion stabilized by bovine casein was reduced by 12% at 37oC during 96-hour incubation compared to the control.  On the other hand, the ability of arabinogalactan, a condensation product of galactose and arabinose at 6:1 ratio, to form an inclusion complex with a guest molecule can improve lutein application, bioavailability, and stability in foods.  Corn oil-in-water emulsion (5% w/w) stabilized with bovine casein (0.5 % w/w) or caprine casein (0.5% w/w), and arabinogalactan at concentration of 0.25% (w/w) was prepared using a high pressure homogenizer.  The pH of the emulsions were adjusted to 7.0.  The chemical stability of lutein was assessed by measuring the changes in lutein concentration in the emulsions during incubation at 25oC for 96 hours using a spectrophotometric method.  The chemical stability of lutein increased significantly (P<0.05) in the caprine casein types I and II compared to bovine casein.  Microencapsulation of lutein with either caprine casein-arabinogalactan or bovine casein-arabinogalactan protected lutein in corn oil-in-water emulsions and significantly reduced (P<0.05) the chemical degradation of lutein at 72 and 96 hours of incubation at 25oC compared to the treatments without arabinogalactan.  This information will be useful for understanding the behavior of lutein emulsions in food products.