Antioxidant capacity of extra-virgin olive oils
- 335 Downloads
In this study, the oxygen radical absorbance capacity (ORAC) of vegetable oils was investigated using a spectrofluorometric method, which measures the protection of the phenolic substances of the oil on the β-phycoerythrin fluorescence decay in comparison with Trolox. More than 97% of the phenolic substances was extracted from the oil using methanol, and the methanolic extract was then used for the ORAC and the total phenolics assay. We found a significant correlation between ORAC values of different olive oils and the total amount of phenolics. For extra-virgin olive oils, maximal ORAC values reached 6.20±0.31 μmol Trolox equivalent/g, while refined and seed oils showed values in the 1–1.5 μmol Trolox equivalent/g range. Our method is useful to assess the quality of olive oils and to predict, in combination with the rancidity tests, their stability against oxidation.
Key WordsExtra-virgin olive oil oxygen radical absorbance capacity (ORAC) peroxyl radicals phenolic compounds
Unable to display preview. Download preview PDF.
- 1.Manna, C., P. Galletti, V. Cucciolla, O. Moltedo, A. Leone, and V. Zappia, The Protective Effect of the Olive Oil Polyphenol (3,4-dihydroxyphenyl)-Ethanol Counteracts Reactive Oxygen Metabolite-Induced Cytotoxicity in Caco-2 Cells, J. Nutr. 127: 286–292 (1997).Google Scholar
- 3.Papadopulos, G., and D. Boskou, Antioxidant Effect of Natural Phenols on Olive Oil, J. Am. Oil Chem. Soc. 68:21–25 (1991).Google Scholar
- 10.Packer, L., M.G. Traber, and W. Xin (eds.), Proceedings of the International Symposium on Natural Antioxidants: Molecular Mechanisms and Health Effects, AOCS Press, Champaign, 1996, 705 pp.Google Scholar
- 13.Singleton, V.L., and J. Rossi, A Colorimetry of Total Phenolics with Phosphomolybdic-Phosphotungstic Acid Reagents, Am. J. Enol. Vitic. 16:144–158 (1965).Google Scholar
- 14.Istituto Poligrafico dello stato, Official Methods of Analysis of Oils and Fats; Ministero Della Agricoltura e Delle Foreste, Roma, 1964.Google Scholar