In the preceding report, from the information of infra red spectrum and electron spin resonances, it was suggested that the oxidation of lipid gave the polymerization and peroxidation products mainly under the mild condition of heating, but addition of sesamol induced the carbonylization from the peroxidation. In this paper, the oxidation of lipid under the condition of heating on the metal surface was reported. In some cases of the oxidations, the new carbonyl absorptions (1730cm-1) appeared in the infra red spectrum that showed the carbonylization from the peroxides. Especially, in the oxidation of triolein on the iron surface, the increase of the absorption (1730cm-1) in infra red spectrum was parallel with the decrease of the peroxide value. Moreover, the degree of the absorption (1730cm-1) was largely effected by the kind of metal. The oxidation on tin generated the strong absorption of 1730cm-1 in the infra red spectrum. On the other hand, in many cases of the oxidations on iron, the absorptions were not observed. These results suggested the useful application of infra red spectrum to studing the oxidation of lipid by the metal catalyst at high temperature. Under the condition as described above, electron spin resonance peak was not detected in the almost cases.
