20.500.12556/RUL-83386 Rapid estimation of tocopherol content in linseed and sunflower oils-reactivity and assay The reactivity of tocopherols with 2,2-diphenyl-1-picrylhydrazyl (DPPH) was studied in model systems in order to establish a method for quantifying vitamin E in plant oils. The method was optimized with respect to solvent composition of the assay medium, which has a large influence on the course of reaction of tocopherols with DPPH. The rate of reaction of α-tocopherol with DPPH is higher than that of γ-tocopherol in both protic and aprotic solvents. In ethyl acetate, routinely applied for the analysis of antioxidant potential (AOP) of plant oils, reactions of tocopherols with DPPH are slower and concentration of tocopherols in the assay has a large influence on their molar reactivity. In 2-propanol, however, two electrons are exchanged for both α- and γ-tocopherols, independent of their concentration. 2-propanol is not toxic and is fully compatible with polypropylene labware. The chromatographically determined content of tocopherols and their molar reactivity in the DPPH assay reveal that only tocopherols contribute to the AOP of sunflower oil, whereas the contribution of tocopherols to the AOP of linseed oil is 75%. The DPPH assay in 2-propanol can be applied for rapid and cheap estimation of vitamin E content in plant oils where tocopherols are major antioxidants. plant oil α-tocopherol γ-tocopherol vitamin E DPPH antioxidants solvent rastlinska olja sončnično olje laneno olje antioksidanti tokoferol vitamin E antioksidativni potencial kemijska kinetika true false true Angleški jezik Slovenski jezik Članek v reviji 2016-06-09 03:19:09 2016-08-17 17:22:13 2022-08-01 23:19:38 0000-00-00 00:00:00 2015 0 0 Str. 14777-14790 iss. 8 Vol. 20 2015 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 664.3:577.161.3:544.4 1420-3049 10.3390/molecules200814777 4555896 18462981 RAZ_Kralj_Cigic_Irena_2015.pdf RAZ_Kralj_Cigic_Irena_2015.pdf 1 964C129B21CFEEB725C8B8CFFAA729BF 1f6c23c1580bbf82675a9e65b81986fb29b3790a4c3f2e5ec1f0be3f974ab7ef 62af9238-15fa-11ec-a523-00155dcfd717 20.500.12556/rul/c107ad44-574f-48d3-ad9e-46749805bd8c https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=147594 https://www.mdpi.com/1420-3049/20/8/14777 0 26238261-15fa-11ec-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=147593 Biotehniška fakulteta Fakulteta za kemijo in kemijsko tehnologijo 0 0 0