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.
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Ninfali, P., Aluigi, G., Bacchiocca, M. et al. Antioxidant capacity of extra-virgin olive oils. J Amer Oil Chem Soc 78, 243–247 (2001). https://doi.org/10.1007/s11746-001-0252-9
- Extra-virgin olive oil
- oxygen radical absorbance capacity (ORAC)
- peroxyl radicals
- phenolic compounds