| Abstrakt: |
The effect of 12, oxo- cis, 9-octadecenoic acid (keto acid) on the autoxidation of stripped corn oil at 37°C. has been studied. The stripped corn oil containing 50 μg. of tocopherol per g. was prepared by Distillation Products Industries by removal of approximately 10% of the corn oil in a molecular still. Addition of 2.5% of the keto acid resulted in a higher rate of oxidation. As the concentration of keto acid was increased from 0 to 10%, peroxides increased rapidly, resulting in a shorter induction period. The antioxidants BHA, BHT, propyl gallate, NDGA, Ethoxyquin, and DPPD were found to lengthen the induction period for stripped corn oil in the presence of keto acid. DPPD was found to be by far the most effective and α-tocopherol acetate had no antioxidant activity in presence of keto acid. It was observed that keto acid oxidized very rapidly with the formation of peroxides and probable breakdown to free radicals. These free radicals then accelerated the autoxidation of stripped corn oil through a chain reaction mechanism. Heptanoic, suberic, and azelaic acids were identified among the breakdown products of keto acid. [ABSTRACT FROM AUTHOR] |
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