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Updated: Aug 6, 2026

Cellular Lipid Extraction for Targeted Stable Isotope Dilution Liquid Chromatography-Mass Spectrometry Analysis
Published on: November 17, 2011
Analysis of alpha-linolenic acid biohydrogenation intermediates in milk fat with emphasis on conjugated linolenic
F Destaillats1, J P Trottier, J M G Galvez
1Department of Food Science and Nutrition, Dairy Research Center (STELA), Université Laval, Sainte Foy, Québec, G1K 7P4, Canada.
Abstract:
Ruminal biohydrogenation of alpha-linolenic acid is not fully understood compared with that of linoleic acid. Some hypothetical intermediates, that is, conjugated isomers of alpha-linolenic acid (cis-9,trans-11,cis-15 and cis-9,trans-13,cis-15 18:3) have never been reported to occur in ruminant fat. Therefore, milk fat was analyzed using a combination of techniques to characterize alpha-linolenic acid biohydrogenation intermediates. Tandem off-line argentation thin-layer chromatography and high-resolution gas-liquid chromatography using a 120-m highly polar, open tubular capillary column coated with 70% cyanoalkyl polysiloxane equivalent material was used for quantification. Structural characterization of fatty acids was achieved by gas-chromatography mass-spectrometry after synthesis of specific azo-derivatives. This study confirmed that minute amounts of alpha-linolenic acid biohydrogenation intermediates are present in milk fat. Routes involved in biohydrogenation of linoleic and alpha-linolenic acids in the rumen and subsequent endogenous metabolism of related biohydrogenation products are discussed.
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