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- Title
Synergistic effect of lecithins for tocopherols: lecithin-based regeneration of α-tocopherol.
- Authors
Doert, Martin; Jaworska, Karolina; Moersel, Joerg-Th.; Kroh, Lothar
- Abstract
Phospholipids synergistically enhance the antioxidant effect of phenolic antioxidants. Mixtures of lecithins, ascorbic acid and tocopherols are known as strong antioxidants. In our study, the mechanism of the synergistic effect of phospholipids with tocopherols was investigated. The oxidative deterioration and the degradation of tocopherols were analyzed in degummed rapeseed oil or in mixtures with ethyl linoleate at 25 or 110 °C. It was shown that lecithins reduce the degradation of tocopherols in rapeseed oil or in ethyl linoleate model system at 25 or 110 °C. It was found that phosphatidylethanolamine (PE) and phosphatidylserine (PS) can regenerate α-tocopheryl quinone (α-TQ) to α-tocopherol at elevated temperatures. The regeneration could be catalyzed by acetic acid. The synergistic effect of PE or PS with α-tocopherol and l-ascorbic acid resulted from the regeneration of α-TQ to α-tocopherol, because PE, l-ascorbic acid and α-tocopherol show the same stabilization effect upon ethyl linoleate as PE, l-ascorbic and α-TQ. Phosphatidylcholine as a non-amine phospholipid does not regenerate α-TQ. However, it improves the regeneration of α-tocopherol from α-tocopheroxyl radicals with l-ascorbic acid in ethyl linoleate through its ability to acts as a phase transfer catalyst between the polar l-ascorbic acid and the unpolar α-tocopheroxyl radicals. A mechanism for the regeneration of α-TQ by PE or PS is suggested. The activation of α-TQ by PE or PS and the formation of α-tocopherones are the key steps of the mechanism.
- Subjects
LECITHIN; VITAMIN E; PHOSPHOLIPIDS; ANTIOXIDANTS; VITAMIN C; RAPESEED
- Publication
European Food Research & Technology, 2012, Vol 235, Issue 5, p915
- ISSN
1438-2377
- Publication type
Article
- DOI
10.1007/s00217-012-1815-7