The oxidative stability was estimated by measuring the oxidation induction time, on a Rancimat 743 apparatus (Metrohm CH, Switzerland).
Filtered, cleaned, dried air (20 L/h) was bubbled through the oil (3.0g) heated at 120±1.6◦C, with the volatile compounds being collected in water, and the increasing water conductivity continuously measured.
The time taken to reach the conductivity inflection was recorded.
In order to avoid contami- nations between samples, after each analysis the glassware was cleaned by boiling with a solution of sodium hydroxide at 2% (w/v) during 1 h, followed by cooling and soaking in distilled water.