Oxidative stability assessment of Bauhinia purpurea seed oil in comparison to two conventional vegetable oils by differential scanning calorimetry and Rancimat methods

The differential scanning calorimetry (DSC) and oxidative stability index (OSI) techniques were applied for evaluating the oxidative stability of Bauhinia purpurea, rice bran and cotton seed oil. The DSC cell temperature was adjusted at four isothermal temperatures (110, 120, 130, and 140 °C) and oxidative DSC curves were obtained under oxygen flow rate of 50 ml/min. During the oxidation reaction the increase of heat was observed with sharp exothermic curve. T0 was the oxidative induction time determined by the downward extrapolated DSC oxidative curve to time axis. The oxidation times (T0) acquired from each oil demonstrated a good correlation, r > 0.99, with the oxidative stability measured by Rancimat method. DSC method is concluded to be useful by consuming shorter time with lesser amount of sample.