Gas chromatography, sensory analysis and electronic nose in the evaluation of black cumin (Nigella sativa L.) aroma quality
Essential oil composition of Nigella sativa L., the enantiomeric ratio of its chiral compounds as well as sensory characteristics were the subject of the study. The evaluation of several samples of N. sativa seeds purchased in retail was performed by gas chromatography, chiral gas chromatography, olfactometry, sensory profile analysis and the electronic nose. Eleven components were identified. Olfactometry revealed p-cymene, thymoquinone and carvacrol as the most important odorants. P-cymene occurred in all of the samples at highest amounts. Six pairs of enantiomers were isolated. All the components showed variability in their enantiomeric ratios, with exception of carvone, which was found with a stable optical purity of the (-)-isomer, not lower than 85%. The dominating attributes in the sensory profile were cardboard, herbal and spicy. Results of sensory profile analysis and the electronic nose, both interpreted by the Principal Component Analysis, gave similar, although not identical differentiation of the samples.