Study of the accelerated oxidation of low and high erucic rapeseed oil

Abstract

AbstractThe oxidation of a low erucic rapeseed oil was compared to the oxidation of a high erucic rapeseed oil in the temperature range 100 to 140 C. The two oils were found to be very similar in the rate of peroxidation, viscosity increase, change of refractive index, oxidation of the individual fatty acids, and hydroperoxide decay. Rate constants and activation energies for the change of these quantities were determined. The rate of hydroperoxide decomposition was found to be of first order for both oils, but there was evidence that a second order mechanism becomes important at temperatures less than 100 C. Butylated hydroxy anisole (BHA) caused decomposition of hydroperoxide and reacted with fatty acid and possibly with natural antioxidants in the oil. It did not react with oxygen. BHA decomposed thermally between 110 and 140 C. BHA is not an effective antioxidant at these temperatures in an oil which contains esters of highly reactive fatty acids.