The structure of the triacylglycerols of meadowfoam oil

The triacylglycerols of meadowfoam oil have been resolved by HPLC in the silver ion and reversed-phase modes, and by the two techniques used in a complementary fashion. The fractions obtained were collected and quantified by gas chromatography of their methyl esters in the presence of an internal standard. Silver ion chromatography gave a distinctive resolution in which fractions differing solely in the position and chain-length of a single monoenoic fatty acyl group were resolved, the order of elution being 11−20∶1, 5−20∶1, 13−22∶1, 5−18∶1 and 9−18∶1. Reversed-phase chromatography also gave fractions containing single positional isomers, (11−20∶1<5−20∶1<13−22∶1<5−22∶1), but the pattern was more difficult to discern since fractions containing 22∶2 tended to overlap with those containing 20∶1. The species (5−20∶1)(5−20∶1)(22∶2), (5−20∶1)(5−20∶1)(5−20∶1) and (5−20∶1)(5−20∶1)(13−20∶1) were found to be the most abundant, and together comprised 67% of the total. A small but significant trilinolein fraction was detected and its presence may have biosynthetic implications.