Differential scanning calorimetric analysis for monitoring the oxidation of heated oils

A simple and reliable differential scanning calorimetric (DSC) method was d eveloped for monitoring the oxidation in heated oils. Three different types of edible oils, namely, corn oil (CO), refined, bleached and deodorised pa lm olein (RBDPO) and soybean oil (SO) were used in this study. The DSC meth od was based on the cooling thermogram of oil samples at a scanning rate of 1 degrees C/min from -30 to -85 degrees C. The cooling thermogram of oil s howed a well-defined single crystallisation peak. Two DSC parameters of thi s single crystallisation peak, namely peak temperature and enthalpy were de termined. In addition to the DSC method, the deterioration of heated oils w as also quantified by means of seven chemical methods. A statistical compar ative study was carried out on the DSC and chemical methods. The results sh ow that there is good correlation between the DSC method and other standard chemical methods. In conclusion, the DSC method offers an alternative for the monitoring of the oxidation of heated oil due to its appreciable time-s aving, use of small samples with minimal preparation, and absence of toxic chemicals. (C) 1999 Elsevier Science Ltd. All rights reserved.