Identification of conjugated fatty acids in the seed oil of Acioa edulis (Prance) syn. Couepia edulis (Chrysobalanaceae)

Abstract

The oil of Acioa edulis has the fatty acid composition: palmitic acid 28.3%, palmitoleic acid 1.3%, stearic acid 6.8%, oleic acid 26.5%, vaccenic acid 1.3%, linoleic acid 8.8%, arachidic acid 0.7%, a‐eleostearic acid 7.3% and a‐licanic acid 19%. The oil was analyzed and components were identified by ultraviolet (UV), infrared (IR), nuclear magnetic resonance OH‐NMR, 13 C‐NMR), gas chromatography/mass spectrometry (GC/ MS) and chemical methods. For transesterification the tetramethylguanidine reagent was used and it was shown that the method is very suitable for conjugated fatty acids. The equivalent chain lengths of α‐eleostearic acid and a‐licanic acid and their all‐trans isomers were determined on DB 23 and OV‐1. The electron impact (El) and chemical ionization (CI) (with isobutane) mass spectra of licanic acid, eleos‐tearic acid and the El mass spectrum of 4‐oxo‐azelaic acid are presented and discussed. Furthermore, a comparison of literature data of seeds with the same common name is presented.