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 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.