Retention of vitamin E and added retinyl palmitate in selected vegetable oils during deep-fat frying and in fried breaded products

Changes of natural vitamin E (tocopherols and tocotrienols) and added retinyl palmitate (12.5 mu g/g or 250 IU/100 kcal) in soybean oil, corn oil, and palm olein were evaluated during stimulated deep-fat frying. Total vitamin E (milligrams per 100 g) decreased more rapidly in palm olein than in soybean or corn oil. The relative stabilities of the vitamin E homologues in the oils were alpha-T > delta-T > beta-T > gamma-T (soybean oil), alpha-T > gamma-T, delta-T > gamma-T3 (corn oil), and alpha-T > delta-T3 > alpha-T3 > gamma-T3 (palm olein). Retinyl palmitate was more stable in palm olein than in soybean or corn oil. Feasibility to fortify frying oils with retinyl palmitate was demonstrated. The increased level of retinyl palmitate in the fried foods indicates that fortification of retinyl palmitate to frying oils can be a useful tool for delivery of vitamin A activity.