Occurrence of estolides in processed Dimorphotheca pluvialis seed oil

Abstract

Samples of oil from Dimorphotheca pluvialis processed by extraction and mechanical expelling were analyzed using supercritical fluid chromatography (SFC), lipase-catalyzed reactions, and 1H-NMR. SFC analysis detected the occurrence of free fatty acid, diglycerides, and unknown materials having molecular weights equivalent to four and five acyl groups. These components were present in larger quantities for oils recovered via mechanical expelling. Results from lipase-catalyzed reactions and NMR analysis suggest the large molecular weight molecules are triglycerides containing additional acyl groups through estolide bonds. The chemical shifts of the olefinic protons on the conjugated double bonds of dimorphecolic [D(+)-18:2 10 t,12 t -OH 9] acid and its estolides appeared at higher ppm values when compared to non-conjugated olefinic absorptions.