The Influence of High Pressure on the Autoxidation of Major Unsaturated Fatty Acid Constituents of Milk

Abstract

The influence of high pressure on the autoxidation of oleic and linoleic acid methyl esters was investigated as it seems to be the model system closest to the problem. The reaction was studied at 0.1, 100, 350 and 600 MPa at 40 °C. Treatment times were 1, 2, 3, 5 and 20 h. Gas chromatographic data of the decrease of oleic acid methyl ester, taken as a measure for the degree of autoxidation, showed no influence of pressure. The autoxidation of linoleic acid methy lester was accelerated by pressures from 350 MPa as shown by gas chromatographic data of the decrease of the educt as well as by the increase of primary oxidation products measured by HPLC or by the increase in UV-absorption at 234 nm. The primary oxidation products were separated by reversed phase HPLC: no effect of pressure on the distribution of isomers was found.