Mustard seeds contains a higher proportion of the volatile mustard oil and strongest flavor Perceived as health benefiting spice, jd fresh mustard seeds are indeed very rich in a phyto-nutrients, minerals, vitamins and anti-oxidants. It's spicy, peppery flavor goes well with other pungent spices like garlic ans chillies. Mustard seed, one of the oldest old spices, adds warmth and heat to your dishes.