Abstract

The purpose of this study was to compare different methods of extraction to determine the fatty acid composition of black cumin seeds. 100 g of the powdered sample either was subjected into SFE equipment using standard procedures or extracted using conventional techniques (methanol or hexane solvents). Identification of fatty acid composition of extracted Nigella sativa oil was performed by using gas chromatography equipped with flame ionization detector (GC/FID). The constituents were identified by comparison of their retention times with those of reference samples. A total of fifteen fatty acids were identified in the fixed oils obtained from black cumin seeds by using SFE and solvent extraction techniques. The results showed that the most abundant fatty acid present in all extracts was linoleic acid. Surprisingly, despite of high potential of SFE technique in obtaining valuable components of herbs, only conventional methods were able to yield some rare fatty acid in NS such as Gamma linolenic acid. Based on condition, the researchers have to choose the method of extraction in order to obtain the best results and certain component.

Key words: Nigella sativa, supercritical fluid extraction, solvent extraction, gas chromatography, fatty acid composition.