Mustard is an annual herb cultivated as oil seed crop or as vegetable or as fodder, of which, 3 species are known for its condiment value. They are pale yellow or white mustard (Brassica hirta), brown mustard (Brassica juncea) and black mustard (Brassica nigra). The leaves of the plant are alternate, long, bristly branched, petiolate, hairy on both sides. Flowers are small, yellow with 4petals, cruciform. Seeds are 1.5-3mm.
The yellow/white mustard is indigenous to Southern Europe, whereas brown mustard is from China introduced to Northern India. The black mustard is endemic in the Southern Mediterranean region. The white mustard is widely cultivated in Australia, China, Chili, Denmark, Italy, Japan, The UK, The Netherlands, North Africa, Canada and USA. Mustard prefers loamy or clayey loam soil. It is grown as rabbi crop in North India. It is raised during rainy season from July to November in South India.
The major processed products are mustard powder used in the manufacture of mayonnaise, dried or dehydrated mustard leaves, whole mustard seeds etc. Whole mustard is used as a flavouring agent in Indian cooking, whereas ground mustard provides flavour and consistency in Bengali fish curries. Mustard flour has preservative and antioxidant properties in addition to providing flavour and colour.