ALPHA-TOCOPHEROL AND GAMMA-TOCOPHEROL AS EFFICIENT ANTIOXIDANTS IN BUTTER OIL TRIACYLGLYCEROLS

Although tocopherols are known to be the most important natural antiox idants in fats and oils, controversial findings of their effects have been made in different model systems. The aim of the experiment was to study the effects of alpha- and gamma-tocopherol at the levels of 2-5 00 mu g/g on the oxidation of purified butter oil triacylglycerols (BO TAGs) at 40 degrees C in the dark for 16 days. Both of the tocopherol s were effective antioxidants. Although BO TAGs without additions bega n to oxidize immediately, BO TAGs with tocopherols remained in the ind uction period throughout the experiment. The antioxidant strength of a lpha-tocopherol was less than that of gamma-tocopherol. More hydropero xides were formed in BO TAGs with at least 100 mu g/g alpha-tocopherol than with less alpha-tocopherol at the same rime being much less than in BO TAGs without tocopherols. Moreover, as the formation of seconda ry oxidation products in BO TAGs with tocopherols was negligible, no p ro-oxidative effect of tocopherols could be found. At low concentratio n (less than or equal to 10 mu g/g) gamma-tocopherol was slightly less stable than alpha-tocopherol.