Ethyl linolenate, was thermally oxidized at 7OoC, 180°C, 250°C in a closed system in the presence of atmospheric oxygen. On the basis of the peroxide curve obtained at each of the three temperat u m , three heating times weIe chosen for the analysis of the volatile decomposition products. These products were identified by gas chromatography-mass spectrometry. The qualitative pattern of the volatile decomposition products was the same for all treatments. Nine of the products were consistent with compounds predicted from cleavage of the conjugated linolenate hydroperoxides, with the C9 0x0-ester and theC8 ethyl ester produced in the largest amounts. Other predicted products were not detected and were hypothesized to undergo further degradations. Although the major effect of temperature was found to be a quantitative one, it was difficult to relate the amounts of oxidation products directly to a temperaturedependent preferential hydroperoxide scission.

Fresh coconut oil was heated under different conditions for 48 hr at 180 C. The heat treatments included heating in vacuo, heating in air and heating in air and water. The samples were distilled under high vacuum and the volatiles thus obtained were analyzed by combined gas chromatography‐mass spectrometry. In all heated samples, a series of n‐alkanes and I‐alkenes, n‐alkanals, methyl alkanones, alkenals, gamma‐and delta‐lactones, methyl and ethyl esters and free fatty acids were identified. The relative amounts of these compounds varied with the type of heat treatment to which the coconut oil was subjected.

No abstract