Identification of 11,15‐octadecadienoic acid from beef and mutton tallow

By means of gas liquid chromatography and thin layer chromatography on Silica gel G/AgNO 3 we isolated some isolinoleic acids from beef and mutton tallow, which by their chromatographical behavior, IR analysis and by double bond determination by ozonolysis are mainly stereo‐isomeric 11,15‐octadecadienoic acids and in a smaller amount stereo‐isomers of 10,15‐octadecadienoic acids. 4‐ Cis ‐ and 4‐ trans ‐heptenals, 2‐ trans ,6‐ cis ‐ and 2‐ trans ,6‐ trans ‐nonadienals have been isolated from the DNPH mixture obtained from the volatile decomposition products of an oxidized synthetic mixture of stereo‐isomeric 11,15‐octadecadienoic acids.