The roots of Horseradish (Armoracia rusticana), a member of the mustard family (Brassicaceae=Cruciferae) are crushed, minced, or powdered to produce the familiar spicy off-white condiment. As in other mustards, the pungent compounds are isothiocyanates. Horseradish is a perennial herb with a long, yellowish buff taproot bearing long-stalked ovate or oblong leaves (30 to 60 cm in length) with coarsely toothed, wavy margins. The species probably originated in southeastern Europe and western Asia, but has long been widely cultivated in Europe as well as North America and the hilly regions of India.
(Vaughan and Geissler 1997)
Horseradish has been cultivated for its root for over 2,000 years. Today, commercial production occurs mainly in North America (led by the State of Illinois; Walters and Wahle 2010) and Europe. Armoracia rusticana is propagated exclusively vegetatively. Like many vegetatively propagated crops, cultivated A. rusticana plants are generally sterile. This species is not known to occur in the wild, although the two other species in the genus, A. macrocarpa and A. sisymbrioides do occur in the wild and reproduce by seed.
(Sampliner et al. 2009)
Production from Horseradish roots of peroxidase (a heme-containing enzyme that utilizes hydrogen peroxide to oxidize a wide variety of organic and inorganic compounds) occurs on a relatively large scale because of the commercial uses of the enzyme, e.g., as a component of clinical diagnostic kits and for immunoassays (Veitch 2004).