The natural antioxidant potencies of alpha-tocopherol (α-toc) and betacarotene (β-car) (each in 100 and 200 ppm) and their binary admixtures were studied. The autoxidation of stripped sunflower oil for 2, 4, 6, 8, 10, 12 and 14 days at 40, 60 and 100ºC were evaluated by measuring peroxide value (PV), para-anisidine values (p-AV) and total oxidation (2PV+p-AV) .It was found that α-toc (200 ppm) is more effective than its lower concentration (100 ppm), while β-car (100 ppm) is more effective than

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... the higher level. The binary mixture of α-toc: β-car (200 ppm: 100 ppm) proves its performance when added to the stripped sunflower oil. Graphical representations of the results show changes of PV and p-AV during periodical heating for different periods. It was concluded that antioxidant activity of α-toc diminished when the tocopherol level exceeds its optimal concentration. It is noteworthy to mention that individual β-car acts as a prooxidant when used at a concentration equal to that of α-tocopherol, because β-car may react with oxygen to form β-carotene peroxyl radicals, these peroxyl radicals may enhance the propagation stage of the oxidation reaction and therefore the antioxidant capacity or "sparing efficiency" of the tocopherol decreases.