Aroma profiles of vegetable oils varying in fatty acid composition vs. concentrations of primary and secondary lipid oxidation products

The aroma compositions of oxidised sunflower oil, linseed oil and a blend t hereof (85/15) were compared with frequently used indicators for primary an d secondary lipid oxidation. Primary lipid oxidation was followed by the fo rmation of conjugated dienes, secondary lipid oxidation by proponal and hex anal formation. Highest concentrations of conjugated dienes and propanal we re measured in the linseed oil, followed by the blend and sunflower oil, re spectively. Highest concentrations of hexanal were determined in the blend. At similar primary oxidation levels, volatile compounds of the oils were i solated in a model mouth system and subsequently analysed by gas chromatogr aphy/sniffing port analysis. Propanal, pentanal, 1-penten-3-one, hexanal, 1 -pentanol, octanal, 1-octen-3-one, 1-octen-3-ol and (E,Z)-2,4-heptadienal p ossessed detectable odours. Comparing the three oils, most aroma compounds and greatest intensities were determined in the blend. Conjugated diene con centrations did not predict the formation of aroma compounds adequately. Al though propanal and hexanal concentrations were reasonable indicators for a roma development in linseed and sunflower oil, respectively, neither of the indicators predicted aroma development in all three oils sufficiently.