Triacylglycerol Species of Less Common Edible Vegetable Oils

Abstract Chromatographic and spectroscopic methods used for the detection and quantification of triacylglycerol (TAG) species present in less common edible vegetable oils (almond, hazelnut, pumpkin seed, safflower, sesame, walnut, and wheatgerm oils) are reviewed. For these oils, as well as for thistle oil and high-oleic sunflower oil, for which no data exist on their TAG composition, both high-performance liquid chromatography (HPLC) and gas chromatography (GC) chromatographic plus spectrometric techniques have also been performed. Triacylglycerol comparison of the data found in the literature is also presented. Five fatty acyl moieties (palmitoyl-, stearoyl-, oleoyl-, linoleoyl-, and linolenoyl-) are found to mainly contribute to the formation of TAG species of the aforementioned edible vegetable oils, whereas six more (palmitoleoyl-, arachidoyl-, gadoleoyl-, heptadecenoyl-, margaroyl-, and erucoyl-) are reported as minors. Only 19 to 33 TAG make up the mass of these oils. These TAG are also found in most common edible oils, thus indicating a “uniformity” in the minor and main TAG composition of edible vegetable oils. Trioleoyl-glycerol predominates in almond (13.3–48.6%), hazelnut (35.3–57.9%), and high oleic sunflower (44.2% and 52.9%) oils, trilinoleoyl-glycerol in safflower (40.1–49.7%), thistle (36.9% and 46.0%), walnut (25.9–38.1%), and wheatgerm (15.7–33.0%) oils. Sesame and pumpkin seed oils are rich in dioleoyl-linoleoyl-glycerol (5.9–17.5%, 9.5% and 18.6%, respectively) and oleoyl-dilinoleoyl-glycerol (8.0–18.7% and 12.8–21.1%, respectively).