Triacylglycerols Of Sunflower Oil Research Articles

Antioxidant activity of selected species of the family Lamiaceae grown in Bulgaria

AbstractThe kinetics of peroxide accumulation during oxidation of triacylglycerols of sunflower oil at 100 °C in presence of different concentrations of hexane, ethylacetate and ethanol extracts of Melissa officinalis L., Mentha piperita L., Mentha spicata L., Ocimum basilicum L., Origanum vulgare L. and Saturejae hortensis L., was followed. Ethanol extracts are the most active in retarding the autoxidation process. The most effective are the extracts of Saturejae hortensis L. (stabilization factor F for 0.5% direct hexane and 0.5% direct ethanol extracts being 14.8 and 24.0, respectively), followed by the extracts of Mentha piperita L. (F = 7.4 and 19.6, respectively) and Melissa officinalis L. (F = 7.4 and 18.6, respectively). Some of the spices are recommended as sources of natural antioxidants for stabilization of polyunsaturated lipid systems.

Antioxidative action of the ethanolic extract and some hydroxycoumarins of Fraxinus ornus bark

The antioxidative effectivity and strength of different concentrations of ethanolic extract from Fraxinus ornus bark, as well as of esculetin, esculin, fraxetin and fraxin during the autoxidation at 100°C of kinetically pure triacylglycerols of lard (TGL) and triacylglycerols of sunflower oil (TGSO) were determined. The extract exhibited a pronounced antioxidative activity. Esculetin and fraxetin considerably retarded the process in both lipid systems, this being more significant in the less oxidizable lipid substrate (TGL). Fraxetin proved to be a more efficient and stronger inhibitor than esculetin. During the oxidation of TGSO the fraxetin caused a stronger decrease in antioxidative activity. The participation of both hydroxycoumarins in the side reactions of inhibited oxidation, which explains their kinetic behaviour, is discussed. Fraxin and esculin displayed a very weak antioxidative action.