Horseradish (Armoracia rusticana, syn. Cochlearia armoracia) is a perennial plant of the Brassicaceae family, which includes mustard and cabbages. The plant is probably native to southeastern Europe and western Asia, but is popular around the world today. It grows up to 1.5 metres (five feet) tall and is mainly cultivated for its large white, tapering root, although the leaves are also edible.

Its root is used as a vegetable or ground in a condiment called prepared horseradish, and has at times been used as the bitter herbs in the Passover meal in some Jewish communities. Horseradish, sometimes blended with cream and called horseradish sauce, is often served with roast or boiled beef or sausages, as well as smoked fish. Horseradish is also used in some prepared mustards. Also, much of what is styled wasabi is actually common horseradish dyed green.

The horseradish root itself has hardly any aroma. When cut or grated, however, enzymes from the damaged plant cells break down sinigrin (a glucosinolate) to produce allyl isothiocyanate (mustard oil), which irritates the sinuses and eyes. Once grated, if not used immediately or mixed in vinegar, the root darkens and loses its pungency and becomes unpleasantly bitter when exposed to air and heat.

Over two thirds of the world's horseradish is said to be grown in a small region around Collinsville, Illinois in the US, the self-styled "Horseradish Capital of the World", whence it is even exported overseas as a gourmet version of the product to places more renowned for consumption of the root. The biggest US production for domestic supply comes from Eau Claire,Wisconsin.

It has been speculated that the word is a partial translation of its German name Meerrettich. The element Meer (meaning 'ocean, sea', although it could be derived from the similar sounding Mähren, the German word for Moravia, an area where the vegetable is cultivated and used extensively) is pronounced like the English word mare, which might have been reinterpreted as horseradish. On the other hand, many English plant names have "horse" as an element denoting strong or coarse, so the etymology of the English word (which is attested in print from at least 1597) is uncertain. (The OED contains no reference to the derivation from the German Meer.)

Horseradish contains potassium, calcium, magnesium and phosphorus, as well as volatile oils, such as mustard oil, which is antibiotic. Fresh, the plant contains 177.9 mg/100 g of vitamin C.

The enzyme horseradish peroxidase, found in the plant, is used extensively in molecular biology in antibody amplification and detection, among other things. For example, "In recent years the technique of marking neurons with the enzyme horseradish peroxidase (HRP) has become a major tool. In its brief history, this method has probably been used by more neurobiologists than have used the Golgi stain since its discovery in 1870."[1]

History

Horseradish was cultivated in antiquity. Cato discusses the plant in his treatises on agriculture, and a mural in Pompeii showing the plant has survived until today. It is probably the plant mentioned by Pliny the Elder in his Natural History under the name of Amoracia, and recommended by him for its medicinal qualities, and possibly the Wild Radish, or raphanos agrios of the Greeks.

Both root and leaves were universally used as a medicine during the Middle Ages, and as a condiment in Denmark and Germany. Before pepper and chiles became widely available, horseradish and mustard were the only sharp spices known in Europe.

William Turner mentions horseradish as Red Cole in his "Herbal" (1551-1568), but not as a condiment. In "The Herball, or Generall Historie of Plantes" (1597), John Gerard describes it under the name of raphanus rusticanus, stating that it occurs wild in several parts of England. After referring to its medicinal uses, he says: "the Horse Radish stamped with a little vinegar put thereto, is commonly used among the Germans for sauce to eate fish with and such like meates as we do mustarde."

It is still used this way in Jewish and Romanian cuisine, where a sweetened horseradish-vinegar sauce called chrain or hrean traditionally accompanies gefilte fish. There are two varieties of chrain— "red" chrain and "white" chrain, i.e. mixed with or without red beet. It is also popular in Poland where it is called chrzan. Having chrzan on the Ester table is a part of Polish Easter tradition. Variety with red beet also exists and it is called cwikla z chrzanem or simply cwikla.

Modern uses

The American fast-food restaurant chain Arby's uses horseradish in its "Horsey Sauce", which is provided as a regular condiment, alongside ketchup, mustard, and mayonnaise. This is not a common practice at its major competitors. In addition, the US fast-food outlet Popeye's serves "quarter pounders with 'radish," in its stores on the East Coast. The reason it doesn't offer this meal in its stores elsewhere is something of a mystery.

Horseradish sauce made from grated horseradish root and cream is a popular condiment in the United Kingdom. It is often served with roast beef, but can be used in a number of other dishes also.

Additionally, since real wasabi is very expensive, even in Japan, most Japanese restaurants around the world actually serve a horseradish mixture that's been dyed green. In fact, some imitation wasabi makers, such as S&B, call horseradish "western wasabi".