On the basis of an autocatalytic and a first order reaction kinetics, a nonisothermal oxidation reaction model was developed for n-3 polyunsaturated fatty acid (PUFA) under temperature-programmed linear heating conditions. With this model, the activation energy of oxidative reaction can easily be obtained with at least three linear heating conditions. The temperature-programmed oxidation experiments of ethyl eicosapentaenoate and ethyl docosahexaenoate were done under linear heating conditions of 4 to 12 K/h. The activation energies and the frequency factors obtained were in good agreement with those by the isothermal oxidation experiments reported previously.
Keywords: DHA; EPA; kinetic energy; temperature-programmed autoxidation.