NMR, GC–MS and ESI‐FTICR‐MS Profiling of Fatty Acids and Triacylglycerols in Some Botswana Seed Oils

Abstract

AbstractIn the search for non‐traditional seed oils, physicochemical parameters, fatty acid (FA) and triacylglycerol (TAG) profiles for five Botswana seed oils, obtained by Soxhlet extraction, were determined. GC–MS and 1H‐NMR analyses showed the FA profiles for mkukubuyo, Sterculia africana, and manketti, Ricinodendron rautanenii, seed oils dominated by linoleic and oleic acids, 26.1, 16.7 and 51.9, 24.4%, respectively, with S. africana containing significant amounts of cyclic FAs (19.9%). Mokolwane, Hyphaene petersiana, seed oil was typically lauric; 12:0 and 14:0 acids were 25.9 and 13.4%, respectively. Morama, Tylosema esculentum, seed oil resembled olive oil; 18:1 (47.3%) and 18:2 (23.4%) acids dominated. Moretologa‐kgomo, Ximenia caffra, seed oil had 45.8% of 18:1 FA, plus significant amounts of very long chain FAs: 26:1 (5.8%), 28:1 (13.9%), 30:1 (3.9%), and acetylenic acids, 9a‐18:1 (1.5%) and 9a, 11t‐18:2 (16.0%). TAG classes and regiochemistry were determined with ESI‐FTICR‐MS, and 13C‐NMR spectra, respectively. Morama showed seven major TAG classes with C54:4 and C54:3 dominating; mokolwane had 16 major classes with C32:0, C38:0 and C42:2 dominating; manketti had 11 major classes with C54:7, C54:6 and C54:4 dominating; mkukubuyo had 12 major classes with C52:4, C52:3 and C54:4 dominating; moretologa‐kgomo had 30 major TAG classes with C64:5, C64:3 and C62:3 dominating. Saturated FAs were generally distributed over the sn‐1(3) position for morama, manketti, and moretologa‐kgomo but at the sn‐2 position for mokolwane and mkukubuyo. These findings indicate that morama and manketti seed oils can be developed for food uses, whilst moretologa‐kgomo and mkukubuyo seed oils only for nonfood uses.