Identification of triacylglycerol species from high-saturated sunflower (Helianthus annuus) mutants.

The triacylglycerol (TAG) composition of oils from new high-saturated sunflower lines has been studied by means of GLC. The TAG profiles have been compared with the TAG reconstruction made after lipase hydrolysis (according to the 2-random 1,3-random theory). New TAG species with asclepic (cis,Delta11-octadecenoic acid, isomer of oleic acid), araquidic, or behenic acids have been synthesized and identified in oils from mutant lines. The TAG molecular species that contain asclepic acid instead of oleic acid have a longer retention time. Because each mutant oil has a specific TAG GLC pattern, this method could be used for a more precise validation of oil type than current fatty acid methyl ester analysis. The comparison of the results obtained by GLC with the reconstruction after pancreatic lipase hydrolysis shows, in general, a good agreement between both methods. However, results shown in this paper show that this is not always the case. TAG species containing two molecules of linoleic acid show a higher presence of palmitic or stearic acid than could be expected from a random distribution. The abundance of SLL increased in proportion to the stearic acid content of the oil, and the amount of TAG species with three unsaturated fatty acids (LLL or OLL) was therefore reduced.