Mustard seeds are the proverbially small seeds of the various mustard plants
In the Indian subcontinent they are often used whole, and are quickly fried in oil until they pop to impart a flavor to the oil.The seeds can come from three different plants: black mustard (B.Nigra) brown Indian mustard (B.Juncea), and white or yellow mustard (B.hirta/Sinapisalba)
Its mainly used for seasoning in Indian cooking. Its gives wonderful aroma and flavour to the receipe. Mustard seeds is also available in all Indian stores nicely packed..