• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.379-385
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• 1993

Antioxidative effectiveness and oxidized products in mixture of methyl linoleate(ML) and phenolic compounds were investigated under oxygen blowing at $37^{\circ}C$ for 9 days. Caffeic acid (3,4-dihydroxy cinnamate ; CML) and phloroglucinol(1,3,5-trihydroxy benzene ; PML) showed higher antioxidative effectiveness for methyl linoleate than 0.05% ${\alpha}-tocopherol$ (TML). Oxidized products in ML group were methyl 8-(2-furyl)-octanoate, 9,13-trans, cis hydroperoxide isomer, 9,13-trans, trans hydroperoxide isomer, and 9-TMSO-12,13-epoxy-10-octadecenoate. In CML group the oxidized products were methyl-8-(2-furyl)-octanoate, 9-trans, cis hydroperoxide isomer and 9-trans, trans hydroperoxide isomer, but 13-hydroxy isomer was not identified. It was shown that CML were oxidized more slowly than ML group and at 6th day of oxidation, caffeic quinone was found to be major oxidized product of caffeic acid. Oxidixed Products in PML group were methyl-8-(2-furyl)-octanoate, 9-trans, cis hydroperoxide isomer, and 9-trans, trans hydroperoxide isomer but phloroglucinol was not oxidized even at the 9th day of reaction.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.307-312
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• 1993

Antioxdant effect was studied in model system with linoleic acid methylester and tocochromanols $({\alpha}-,\;{\beta}-,\;{\gamma}-,\;{\delta}-tocopherol\;and \;{\alpha}-,\;{\gamma}-,\;{\delta}-tocotrienol)$ under definite autoxidation condition-temperature $(40,\;60,\;80^{\circ}C),\;O_2\;(0,\;10,\;20%\;O_2\;in\;N_2)$. 13-Hydroperoxy-9-cis-11-trans-, 13-hydroperoxy-9-trans-11-trans-, 9-hydroperoxy-10-trans-12-cis-, 9-hydroperoxy-10-trans-12-trans-octadecadienoic acid methylester as the major oxidation product were produced from linoleic acid methylester by autoxidation, analyzed with HPLC and antioxidant activities were compared by their quantitative changes. Experimental results showed that all added tocochromanols except ${\alpha}-tocotrienol$ had antioxidant effect at $60^{\circ}C$, and also ${\alpha}-tocopherol$, ${\alpha}-tocotrienol$ and ${\delta}-tocotrienol$ had prooxidant effect at $80^{\circ}C$. And cis/trans-hydroperoxide was predominantly produced at $40^{\circ}C$, but trans/trans-hydroperoxide at $80^{\circ}C$. Except no reproductive experimental data in produced hydroperoxides amount, the production ratio of cis/trans-:trans/trans-hydroperoxides in the autoxidation condition of range from $40^{\circ}C/10%,\;O_2\;to\;60^{\circ}C/20%\;O_2$ were as follows: ${\alpha}-T>{\alpha}-T_3>{\gamma}-T>{\beta}-T>{\gamma}-T_3>{\delta}-T>{\delta}-T_3$. This result showed that ${\alpha}-tocopherol$ among tocochromanols had the lowest antioxidant effect.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.614-619
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• 1993

Oxidation mechanisms of methyl linoleate with ${\alpha}-Tocopherol$(TML) were investigated by determining oxidized products using GC-MS during oxidation at $37^{\circ}C$ for 9 days. Oxidized products of TML were found to be methyl octanoate, methyl-8-(2-furyl)-octanoate, 9,13-trans, cis isomer and 9,13-trans, trans isomer. In previous report, oxidation products of methyl linoleate(ML) were methyl-8-(2-furyl)octanoate, 9,13-trans, cis hydroperoxide isomer, 9,13-trans, trans hydroperoxide isomer, and 9-TMSO-12,13-epoxy-10-octadecenoate. In the case of ML, 9-TMSO-12,13-epoxy-l0-octadecenoate was produced instead of methyl octanoate in TML. ${\alpha}-Tocopherol$ quinone, as a major oxidized product of ${\alpha}-Tocopherol$ was formed at the 6th day of oxidation. ${\alpha}-Tocopherol$ quinone was produced rather quickly in lipid media than aqueous media. In oxidation of methyl linoleate, it was shown that the first oxidized product was methyl-9,13-hydroxy-octadecadienoate. As second products, methyl-8-(2-furyl)-octanoate, 9-TMSO-12,13-epoxy-10-octadenoate, and methyl octanoate were oxidized from methyl-9-hydroxy-10-trans, 12-trans-octadecadienoate.