Black seeds is a flowering plant, native to southwest Asia that grows to 20-30 cm tall with linear leaves. The flowers are delicate, and usually colored pale blue and white, with 5-10 petals. The fruit is a large and inflated capsule composed of 3-7 united follicles, each containing numerous seeds. The seed is usually used as a spice.
There are many similar names of this spice. Black seeds is also known as Kalonji (Hindi), Kezah (Hebrew), Habbat-el-barakah (literally seeds of blessing Arabic) or Siyah Daneh (Persian). In English, it is called Fennel Flower, Black Caraway, Nutmeg Flower or Roman Coriander. Other names used, sometimes misleadingly, are Onion Seed and Black Sesame. Frequently the seeds are referred to as Black Cumin; this is, however, also used for a different spice, Bunium Persicum. It is also sometimes just referred to as Nigella or Black Seed. An old English name gith is now used for the corn cockle.
Black seeds belongs to the Plant family of Ranunculaceae (buttercup family). Black seeds have little odor, but when ground or chewed they develop a vaguely oregano-like scent. The taste is aromatic and slightly bitter;
Black seeds originated probably from Western Asia.Today, the plant is cultivated from Egypt to India.
Black seeds contain numerous esters of structurally unusual unsaturated fatty acids with terpene alcohols (7%); furthermore, traces of alkaloids are found which belong to two different types: isochinoline alkaloids are represented by nigellimin and nigellimin-N-oxide, and pyrazol alkaloids include nigellidin and nigellicin.
In the essential oil (avr. 0.5%, max. 1.5%), thymoquinone was identified as the main component (up to 50%) besides p-cymene (40%), a-pinene (up to 15%), dithymoquinone and thymohydroquinone. Other terpene derivatives were found only in trace amounts: Carvacrol, carvone, limonene, 4-terpineol, citronellol. Furthermore, the essential oil contains significant (10%) amounts of fatty acid ethyl esters. On storage, thymoquinone yields dithymoquinonene and higher oligocondensation products (nigellone).
The seeds also contain a fatty oil rich in unsaturated fatty acids, mainly linoleic acid (50 – 60%), oleic acid (20%), eicodadienoic acid (3%) and dihomolinoleic acid (10%) which is characteristic for the genus. Saturated fatty acids (palmitic, stearic acid) amount to about 30% or less. Commercial nigella oil (“Black Seed Oil”, “Black Cumin Oil”) may also contain parts of the essential oil, mostly thymoquinone, by which it acquires an aromatic flavor.
