Mustard seeds are very rich in calcium, manganese, omega 3 fatty acids, iron, zinc, protein and dietary fiber. For people who suffer from a bad appetite, here's something that will be really helpful. Mix a few black mustard seeds with milk and have it 15 to 20 minutes before your meal. In Indian cuisine, mustard seeds are toasted in oil before they are added to the dish. Powdered mustard acts as an emulsifier in the preparation of condiment, and salad dressings. Mustard has a strong pungent flavor, and unlike any other spice it has virtually no aroma.