Monitoring of rapeseed oil autoxidation with a pressure differential scanning calorimeter

Samples of rapeseed oils stored at room conditions were used for determination of peroxides values (PV) by iodometric titration and for thermoanalytical parameters (t(ON) and t(max)) determined with a pressure differential scanning calorimeter when used in the isothermal mode. The assessment of oxidative stabilities and the anticipation of the oxidative fate of oils based on a single PV or on t(ON) and t(max) determination is rather uncertain. The linear correlation of t(ON) and t(max) vs. PVs makes possible a comparative assessment of the oxidative stabilities of the oils studied. Such assessments can be performed only for oils not reprocessed which show PV less than or equal to 30 mmol O-2(2-)/kg of oil. The use of pressure differential isothermal calorimetry enables a more rapid stability assessment than the use of PV measurements alone. (C) 1997 Elsevier Science B.V.