Oil content and fatty acid composition of seeds of Guizotia cass (Compositae)

Abstract

Seeds of Guizotia abyssinica and wild Guizotia were analysed for oil content and fatty acid composition by multisequential and gas chromatographic methods, respectively. The oil content of G abyssinica ranged from 416 to 436 g kg(-1) (weight per kg dry matter of seeds) and that of the wild Guizotia taxa from 214 to 328 g kg(-1). Two unsaturated fatty acids (linoleic (54.3-72.8, weight percent of total oil) and oleic (5.4-26.8% of oil by wt) and two saturated fatty acids (palmitic (7.8-10%) and stearic (5.5-8.1%)) were about 91-97% of the fatty acids present. Palmitoleic, linolenic, arachidic, eicosenoic, behenic, erucic and lignoceric acids constituted about 2-3%. An unidentified fatty acid, probably an epoxy form of C:20 or C:22, has been found in all the materials and it was 11-66%. Total saturated and unsaturated fatty acids were about 74-84% and 15-20%, respectively. Differentiation in fatty acid composition between the taxa is too small to be of taxonomic use. It is inferred that when gene transfer is desired hybridisation between the wild and cultivated taxa may not affect the oil quality of the latter and the oils of the wild taxa are possibly safe for human consumption.