Abstract
The oxidation products of both types of mixtures of α- tocopherol (α-Toc) and Ttocopherol (γ-Toc) or α-Toc and δ-tocopherol (δ-Toc) during autoxidation of methyl linoleate were isolated and iden-tified. The structures of the oxidation products were characterized by UV, IR, 1H and 13C NMR, and mass spectrometry. The 5-[2-(α-tocopherol-5'-yl)ethyl]-a-tocopherylquinone, 5-[2-(α-tocopherol-5'-yl)ethyl]-8a-hy-droxy-α-tocopherone, and O-[8-(5-ethoxymethyl-7-methyltocol)methyl]-α-tocopherol were obtained from both types of the mixtures as the oxida-tion products derived from α-Toc. γ-Toc diphenyl ether dimer (γ-TED) and γ-Toc biphenyl dimer (γ-TBD) were identified from the mixture of α-Toc and y Toc, and δ-Toc diphenyl ether dimer (δTED) from the mixture of α-Toc and δ-Toc. However, no oxidation product composed of both α-Toc and γ-Toc or δ-Toc was detected in oxidation products of both types of the mixtures. These results support the facts that, at first, oxidation of α-Toc proceeds during autoxidation of lipids and then γ-Toc or δ-Toc decomposes after approximate consumption of α-Toc.
