Effect of Carrier Type and Amount on Vitamin A Light Degradation in Fortified Lowfat and Skim Milks

Abstract

Effects of type and amount of retinyl palmitate carrier on light stability of all-trans retinyl palmitate in fortified lowfat milks were investigated. Skim and 2% fat milks were fortified with retinyl palmitate using butter, coconut, corn, or peanut oil as the vitamin carrier. After pasteurization and homogenization, fortified milk samples were exposed to light in glass tubes. At regular intervals, samples were removed from light and analyzed for all-trans retinyl palmitate using high performance liquid chromatography. Less light-induced loss of all-trans retinyl palmitate occurred in skim and 2% fat milks fortified using butter or coconut oil than those using corn or peanut oil. Amount of coconut or corn oil used to incorporate retinyl palmitate also played a role in its light-induced degradation rate. At a carrier concentration of .001% (vol/vol) in skim milk, light degradation of all-trans retinyl palmitate proceeded approximately twice as fast as .01 or .1% (vol/vol). Addition of Tween 80 as an emulsifier had negligible effect on retinyl palmitate light degradation in fortified skim milk.