Rapid estimation of tocopherol content in linseed and sunflower oils-reactivity and assay

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

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.

• Language: English
• Keywords: plant oil, α-tocopherol, γ-tocopherol, vitamin E, DPPH, antioxidants, solvent
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty; FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2015
• Number of pages: Str. 14777-14790
• Numbering: Vol. 20, iss. 8
• PID: 20.500.12556/RUL-83386
• UDC: 664.3:577.161.3:544.4
• ISSN on article: 1420-3049
• DOI: 10.3390/molecules200814777
• COBISS.SI-ID: 4555896
• Publication date in RUL: 17.08.2016

Record is a part of a journal

• Title: Molecules
• Shortened title: Molecules
• Publisher: MDPI
• ISSN: 1420-3049
• COBISS.SI-ID: 18462981

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 13.08.2015

Secondary language

• Language: Slovenian
• Keywords: rastlinska olja, sončnično olje, laneno olje, antioksidanti, tokoferol, vitamin E, antioksidativni potencial, kemijska kinetika