The initial stages of autoxidation

The autoxidation of polyunsaturated lipids is initiated by a discrete reaction occurring prior to the formation of stable hydroperoxides. The products of the initiating reaction were detected by thin‐layer chromatography and by ultraviolet spectral analysis. The reaction initiating autoxidation does not necessarily involve interactions with metals, although it is catalyzed by some heavy metals when these are present in sufficient concentrations. ॅ‐Tocopherol does not inhibit the initiation reaction, and in general, the stability of preparations of esters of polyunsaturated fatty acids is related to the content of prooxygenic substances resulting from this reaction. By taking special precautions to remove these prooxygenic substances, methyl esters containing as many as six double bonds were prepared having significant induction periods at 40C during which there was no measurable uptake of oxygen.