SYNERGISTIC ANTIOXIDANT EFFECTS OF ORGANIC-ACIDS AND THEIR DERIVATIVES WITH TOCOPHEROLS ON COOKIES

The synergistic antioxidant effects of organic acids and their derivat ives with tocopherol (Toc) on cookies was studied. As a synergist, L-a scorbic acid (AA) and its stearyl ester (AS), erythorbic acid (EA), ci tric acid (CA) and its isopropyl ester (IPC) were used and one of them was added to cookie dough with or without of alpha-, delta-Toc and a mixed tocopherols concentrate (m-Toc). Baked cookies were stored at 40 -degrees-C for 12 months, and periodically analyzed on peroxide value (PV) of extracted oil and residual ratios of Toc and synergists. (1) A S showed a clear antioxidant effect on cookies, strongly suppressed th e prooxidant effect of alpha-Toc, and synergistically enhanced the ant ioxidant effects of delta- and m-Toc. These effects become stronger wi th an increase in the added amount of AS. The addition of more than 1 000 ppm of AS along with 100 ppm of delta-Toc was the most effective, and resulted in the complete inhibition of elevation of PV during the storage for 8 months. On the other hand, AA, EA, CA and IPC hardly sho wed such antioxidant effect and synergistic effect with Tocs. (2) The residual ratio of Tocs in cookies were improved by the addition of AS. The improvement was remarkable in that of alpha-Toc. However, no impr ovement was observed in the addition of AA, EA, CA or IPC. (3) AS in c ookies entirely disappeared within the storage for 5 months, but its s ynergistic antioxidant effect with Toc on cookies was still kept even after its disappearance. In the cookies which had delta-or m-Toc, resi dual ratio of EA or AA was higher than that of AS, but their effects o n the oxidative stability of cookies were small.