Free Access
Reprod. Nutr. Dev.
Volume 44, Number 5, September-October 2004
Page(s) 459 - 464
Reprod. Nutr. Dev. 44 (2004) 459-464
DOI: 10.1051/rnd:2004048

Complete stereospecific determination of conjugated linoleic acids in triacylglycerol of milk-fat

Karine Valeille and Jean-Charles Martin

Laboratoire d'Endocrinologie de la Nutrition, Bat. 447, Université de Paris-Sud, 91405 Orsay Cedex, France

(Received 18 March 2004; accepted 4 June 2004)

Abstract - We analyzed two kinds of dairy fat differing in their contents of cis9,trans11-conjugated linoleic acid (cis9,trans11-CLA or rumenic acid), and determined the positional distribution of this CLA-isomer within the three sn- positions of the triacylglycerol. In the high rumenic acid fat (HR), the CLA-isomers amounted to 2.1% of total fatty acids, and 0.8% in the low rumenic acid fat (LR). Over 90% of the total CLA-isomers were in the form of rumenic acid, with an identical isomeric CLA distribution in both fats. The two fats differed mainly with regards to their contents in palmitic acid, a-linolenic acid, and isomers of trans-C18:1. Conversely, our stereospecific determination indicates that the positional distribution of rumenic acid is preserved among both types of fat, and is more specific for the sn-3 position of the triacylglycerol (54 to 64% of the total rumenic acid). Such a positional distribution is believed to be nutritionally relevant.

Key words: conjugated linoleic acid / milk-fat / positional distribution

Corresponding author: Jean-Charles Martin

© INRA, EDP Sciences 2004