Monoethylenic fatty acids of a partially hydrogenated herring oil.

A Canadian Atlantic herring oil hydrogenated for margarine use to an iodine value of 76 and melting point of 32.5 C was found to have 30% saturated acids and 66% monounsaturated fatty acids. The monounsaturated fatty acids could be analytically determined as cis and trans isomers by open tubular gas liquid chromatography. Trans acids were 33% of the C and C monounsaturated acids, and 32 and 28%, respectively, of the C and C monounsaturated acids. After separation of geometric isomers by Florisil-silver nitrate chromatography the positional isomers in each class were determined by oxidative fission. The double bond positions of the original cis fatty acids were largely retained in both cis and trans isomers, but additional isomers were observed, especially in the trans fatty acids. [ABSTRACT FROM AUTHOR]