Monitoring the quality of heating oils and their blends by different physical methods

The repeated usage of heating oils has been proven hazardous due to the degradation process by chemical reactions that lead to changes in the quality of the oil. There are numerous analytical methods which are capable of monitoring the quality deterioration in heating oils due to their repeated heating in deep fat frying processes. This work explores the effect of heating on the physical behaviour of soybean and rapeseed oils and their blends. Colour measurements, electrical impedance and differential scanning calorimetry (DSC) were used for monitoring the changes in oils and their blends due to the heating process. The results revealed that all methods are able to respond to the oil changes due to the heating process with different levels of accuracy. It was obvious that, colour measurements represented a high level of standard deviation. Electrical impedance showed its ability to be a candidate as a rapid monitoring method. Also, DSC was able to follow small changes in oils along with heating. Further tests are required to confirm the efficacy of the aforementioned methods using more oil blends to generalize the results..