title: Evaluation of total reducing power of edible oils.
abstract: The lipophilicity of untreated edible oils narrows the application of most published methods for the determination of antioxidant activity to hydrophilic extracts of oils. This research addresses the issue of the estimation of the total antioxidant properties of untreated edible oils by modifying two widely applied analytical methods, the Fe-Phenanthroline and the CUPRAC assays, to be used in untreated oils. The modifications pertain to the selection of mixture of solvents (ethanol-butanol in 3:1 v/v ratio), and the optimization of the reaction conditions (reagents concentration and reaction time). The developed methods were applied to a number of hydrophilic and lipophilic standard compounds and different types of commercial edible oils, as well as their corresponding aqueous or organic extracts. This implementation elucidated the differences in the antioxidant content of edible oils. All the results were compared to those of the DPPH and Folin-Ciocalteu methods and the analytical figures of merit for the methods have been estimated. Lastly, it was concluded that the modified CUPRAC assay has higher sensitivity compared to the Fe-Phenanthroline assay.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, School of Sciences, National and Kapodistrian University of Athens, Panepistiomiopolis, 15771 Athens, Greece; Division of Physical Chemistry, IAMPPNM, NCSR Demokritos, Agia Paraskevi Attikis, 15310 Athens, Greece.
authors.forename: Dionysios C
authors.initials: DC
authors.lastname: Christodouleas
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, School of Sciences, National and Kapodistrian University of Athens, Panepistiomiopolis, 15771 Athens, Greece.
authors.forename: Charalambos
authors.initials: C
authors.lastname: Fotakis
authors.affiliation: Division of Physical Chemistry, IAMPPNM, NCSR Demokritos, Agia Paraskevi Attikis, 15310 Athens, Greece.
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Papadopoulos
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, School of Sciences, National and Kapodistrian University of Athens, Panepistiomiopolis, 15771 Athens, Greece. Electronic address: calokerinos@chem.uoa.gr.
authors.forename: Antony C
authors.initials: AC
authors.lastname: Calokerinos
mesh_terms: D001681:Biological Assay / Q000379:methods*; D015374:Biosensing Techniques; D001713:Biphenyl Compounds / Q000737:chemistry / Q000494:pharmacology; D003300:Copper / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008982:Molybdenum / Q000737:chemistry; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry / Q000494:pharmacology; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D013053:Spectrophotometry / Q000379:methods*; D017973:Tungsten Compounds / Q000737:chemistry
chemical_list: D001713:Biphenyl Compounds; C029556:Folin's phenol reagent; D010618:Phenanthrolines; D010851:Picrates; D010938:Plant Oils; D017973:Tungsten Compounds; D003300:Copper; D008982:Molybdenum; C004931:1,1-diphenyl-2-picrylhydrazyl; D007501:Iron
keywords: Antioxidants; CUPRAC; Edible oils; Fe-Phenanthroline; Reducing power