Mustard belongs to the Brassica family of plants. Mustard seed contains a high proportion of protein, about 30-35%. Some of these proteins are known to be allergenic, such as Sin a 1 and Bra j 1. These proteins are predominantly heat resistant making them stable to different production processes. In addition to brown mustard (Brassica juncea) and black mustard (Brassica nigra) primarily yellow mustard (Sinapsis alba) is used as an ingredient in many foods and food preparations.