Study on the autoxidation kinetics of fat components by differential scanning calorimetry. 2. Unsaturated fatty acids and their esters

Natural unsaturated fatty acids oleic, erucic, linoleic, and linolenic and their ethyl esters and, additionally, glycerol trioleate and trilinoleate w ere oxidized with linear-programmed heating rates of 1-25 K/min at 50-300 d egrees C. The oxidation course was monitored by differential scanning calor imetry to determine the oxidative stability of these fat components without any solvents and in the absence of free-radical initiators; i.e., in condi tions of industrial processing and exploitation. The kinetic parameters of oxidation of investigated compounds were obtained by the Ozawa-Flynn-Wall m ethod. The activation energies, preexponential factors, and rate constants of oxidation concern the gross reactivity of oxidized compounds. The start of oxidation and the overall oxidation rate constants were dependent on the number of double bonds in the carbon chain. Esters are more stable than fr ee fatty acids.