Autoxidation of polyunsaturated fatty compounds in mackerel oil: Formation of 2,4,7‐decatrienals

The formation of potentially “fishy” off flavor components, especially 2,4,7‐decatrienals, in various rancid mackerel oils has been semiquantitatively investigated using preparative thin layer chromatography (TLC) and gas liquid chromatography (GLC) methods. A combination of 2 GLC analyses can be directly employed for free aldehyde analysis. This GLC method is faster and gives a better recovery than the alternative TLC proceeding through the dinitrophenylhydrazone derivatives of the carbonyl compounds. Kinetic relations between decatrienal formation and the degree of autoxidation of polyenoic fatty compounds present in mackerel oil are discussed. The decreases in major polyenoic fatty acids rancid oils, measured by the ratios urn:x-wiley:0003021x:equation:aocs0349-math-0001 or urn:x-wiley:0003021x:equation:aocs0349-math-0002 can be related to the formation of 2,4,7‐decatrienals and other unsaturated aldehydes.