| Autor: |
Kazuo Mukai, Ayaka Ohara, Masayuki Hirata, Shin-ichi Nagaoka, Junya Ito, Eri Kobayashi, Kiyotaka Nakagawa |
| Předmět: |
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| Zdroj: |
Journal of Oleo Science; 2019, Vol. 68 Issue 1, p21-31, 11p |
| Abstrakt: |
A kinetic study of the reaction of singlet oxygen (¹O2) with eight vegetable oils 1-8 containing different concentrations of tocopherols (Tocs) and tocotrienols (Toc-3s) was performed. The second-order rate constants (kQ) for the reaction of ¹O2 with vegetable oils 1-8 (rice bran, perilla, rape seed, safflower, grape seed, sesame, extra virgin olive, and olive oils) were measured in ethanol/chloroform/D2O (50:50:1, v/v/v) solution at 35° using UV-vis spectrophotometry. Furthermore, comparisons of kQ values determined for the above oils 1-8 with the sum of the product {ΣkQ AO-i [AO-i]/105} of the kQ AO-i values obtained for each antioxidant (AO-i) and concentration (in mg/100 g) ([AO-i]/105) of AO-i (Tocs and Toc-3s) contained in the oils 1-8 were performed. The observed kQ values were not reproduced by the kQ values calculated using only the concentrations of the four Tocs and Toc-3s. These results suggest that the contribution of fatty acids contained in the oils 1-8 is also necessary to fully explain the kQ values. Recently, the second-order rate constants (kS) for the reaction of aroxyl radical (ArO・) with the same vegetable oils 1-8 were measured in the same solvent at 25° using stopped-flow spectrophotometry (Ref. 23). The kS values obtained could be well explained as the sum of the product {Σ kS AO-i [AO-i]/105} of the kS AO-i and the [AO-i]/105 of AO-i (Tocs and Toc-3s) contained in the vegetable oils. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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