The Evaluation of Deterioration of Plant Oils by Thermogravimetry

We are studying the deterioration of plant oil by thermogravimetry. We had reported that the behaviors of the TG curves of the deteriorated oil prepared at 100°C around weight decrease point was highly correlative to the peroxide value (POV). In this report, the autoxidated oil and the oil used at rice cracker production under most highest temperature were measured by thermogravimetry. In the case of rapeseed oil autoxidation, the TG curves at 190-290°C were recognized as behaving characteristically, namely those decreasing ratio has correlated with the POV and carbonyl value (COV), of which correlation coefficient was above 0.95. In the case of rice bran oil heating at high temperature (240-250°C), the temperature of 1% amount decreased point of TG curves has correlated with COV, acid value (AV) and color difference (ΔE), of which coefficients were above 0.91. From these results, it was suggested that the deterioration of plant oil will be evaluated by thermogravimetry.