Horseradish

horseradish Armoracia rusticana, a potent condiment. It is not a kind of radish; both plants, however, belong to the crucifer family which also includes turnip, cabbage, and mustard. The pungent odour and ‘hot’ taste of horseradish are due to a substance called sinigrin which, when it is decomposed by the action of enzymes, liberates a volatile oil, similar to mustard oil, containing sulphur. The release of these properties only occurs when the root is cut or bruised; an unbroken root has no smell.