Positional analysis and determination of triacylglycerol structure ofArgania spinosa seed oil

Abstract

The distribution of fatty acids between the sn‐1, sn‐2 and sn‐3 positions of triacylglycerols fromArgania spinosa seed oil of Morocco has been determined. Saturated fatty acids showed a preference for external positions. The sn‐1 position contained slightly more palmitic acid than the sn‐3 position, whereas stearic acid was preferentially esterified at the sn‐3 position. Linoleic acid occurred predominantly in the sn‐2 position with lesser amount evenly distributed between the sn‐1 and the sn‐3 positions, as generally found in vegetable oils. Oleic acid was distributed with a slight preference shown for the internal position, whereas the distribution between the external positions revealed a slight preference for the sn‐1 position. The distribution of the triacylglycerols determined from high‐performance liquid chromatography (HPLC) is at variance with that calculated from the 1‐random 2‐random 3‐random distribution theory. This is particularly true for trioleoyl and trilinoleoylglycerols. In contrast, the agreement between theory and experiment is good for triacylglycerols containing two oleoyl and one linoleoyl chains, one oleoyl, one linoleoyl and one palmitoyl chains or one oleoyl, one palmitoyl, and one stearoyl chains.