421 © Springer Nature Switzerland AG 2021 M. F. Ramadan (ed.), Black cumin (Nigella sativa) seeds: Chemistry, Technology, Functionality, and Applications, Food Bioactive Ingredients, https://doi.org/10.1007/978-3-030-48798-0_27 Chapter 27 Effect of Processing on the Composition and Quality of Nigella sativa Essential Oil Faten M. Ibrahim and S. F. El Habbasha Abstract Nigella sativa L. is an annual herb of the Ranunculaceae family. The seeds called black cumin seed which contains 34–39% oil. Its oil has many purposes in traditional medicine and food industries. Black seed oil is a signifcant source of essential fatty acids, tocopherols, phytosterols, phenolics, essential oils, and other bioactive compounds. Thymoquinone (TQ) is one of the potent active compounds in the essential oil fraction of black seed oil with many health benefcial properties. Black seed oil is getting much attention either used alone or in combination with other vegetable oils. Providing information about the black seeds originating from different parts of the world, their oil composition and the effect of deferent extrac- tion methods on the oil quality is of great value. Environmental condition, maturity stage and storage conditions have also signifcant effects on the oil properties. Keywords Nigella sativa · Processing · Extraction method · Essential oil · Chemical composition 1 Nigella sativa Nigella sativa L., an annual herb belongs to the family Ranunculaceae. Nigella herbs and spices are invaluable resources, useful in daily life and different forms i.e., food additives, favours, fragrances, colours, pharmaceuticals, and medicine. It is commonly known as black cumin and is widely distributed and cultivated in Mediterranean countries, Middle Europe and Western Asia. It is an annual aromatic F. M. Ibrahim (*) Medicinal and Aromatic Plants Research Department, National Research Centre, Dokki, Giza, Egypt. S. F. El Habbasha Field Crops Research Department, National Research Centre, Dokki, Giza, Egypt.