Diversity of Black Cumin Genotypes and Their Classification Based on Functional Properties

Abstract

This study aims to examine the phenological, morphological, and chemical diversity of black cumin genotypes to identify those most suitable for food and medicinal use. Thymoquinone content, together with fatty acid composition, were studied in seed oils obtained by cold pressing. Multivariate analysis of the results revealed significant interspecies variation between the genotypes of Nigella damascena and N. sativa. Furthermore, N. sativa genotypes are clustered into two intraspecific groups, largely differentiable on the basis of earliness or lateness of the genotype, seed length and size, thymoquinone content and harvest index. In particular, the thymoquinone content in the samples varied between 0.5% and 4.9%. The fatty acid composition, whose most abundant constituents were linoleic acid, oleic acid and palmitic acid, did not show a significant difference between the intraspecific groups of N. sativa. Genotypes with thymoquinone content above 4% were selected for medicinal use and classified as "medicinal black cumin", whereas those with low levels of thymoquinone were selected for use as culinary spices and baked goods, therefore classified as "spice black cumin". The acquired data brings new insights for revising standards and monographs tailored to the intended use of each genotype.