Tjaša Prevc (Author), Alenka Levart (Author), Irena Kralj Cigić (Author), Janez Salobir (Author), Nataša Poklar Ulrih (Author), Blaž Cigić (Author)

Abstract

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.

Keywords

rastlinska olja;sončnično olje;laneno olje;antioksidanti;tokoferol;vitamin E;antioksidativni potencial;kemijska kinetika;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL BF - Biotechnical Faculty
UDC: 664.3:577.161.3:544.4
COBISS: 4555896 Link will open in a new window
ISSN: 1420-3049
Views: 1019
Downloads: 377
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Other data

Secondary language: Slovenian
Secondary keywords: rastlinska olja;sončnično olje;laneno olje;antioksidanti;tokoferol;vitamin E;antioksidativni potencial;kemijska kinetika;
Type (COBISS): Article
Pages: str. 14777-14790
Issue: ǂVol. ǂ20
Chronology: 2015
DOI: 10.3390/molecules200814777
ID: 9142941