The synergistic antioxidant effects of tocopherol (Toc) and L-ascorbyl stearate or riboflavine tetrabutyrate on lard and palm oil were investigated by the oven and AOM tests. The antioxidant effects of these esters were also studied in the same manner.
The addition of monoglyceride in the test on L-ascorbyl stearate was examined so as to make a comparison with the results of the test on L-ascorbic acid reported previously [Yukagaku, 33, 361 (1984)].
1) On lard, L-ascorbyl stearate showed little antioxidant effect, but improved slightly the antioxidant effect of Toc.
2) On palm oil, L-ascorbyl stearate had a stronger antioxidant effect than L-ascorbic acid. In particular, the period to attain POV 100 tended to increase with ester concentration. However, no synergistic effects with Toc were found.
3) The addition of monoglyceride improved the antioxidant effect of L-ascorbyl stearate and its synergistic effect with Toc on lard. These effects were almost comparable to those of L-ascorbic acid reported previously.
4) Riboflavine tetrabutyrate showed no antioxidant effects nor improved the antioxidant effect of Toc on fat, in vitro.
