To determine the cut-off conjugated diene values for rejection of oleic, oleic-linoleic, and linolenic groups of vegetable oils, kinetics of change in the conjugated diene (CDV) and carbonyl (CV) values of olive, sunflower, and canola oils were investigated over oxidations at 60 °C and 90 °C. With respect to the cut-off CVs for sensory (24 μmol g–1) and toxicological (41 μmol g–1) rejections of edible fats and oils, the CDVs at the induction periods (IP) of the oils studied at 60 °C were adopted as the cut-off values for rejection purposes. The cut-off CDVs for discarding the oils were calculated to be 9.0, 13.5, and 13.0 µmol g–1 for the olive, sunflower, and canola oils, respectively. Moreover, the ratio between IP and CV at IP (OPIC, h g μmol–1) provided a more comprehensive measure than each one alone to show the higher oxidative stability of the olive oil (36.2 and 2.95 at 60 °C and 90 °C, respectively) than the canola (16.6 and 2.21 at 60 °C and 90 °C, respectively) and sunflower (8.72 and 1.67 at 60 °C and 90 °C, respectively) oils.

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