Horseradish (Armoracia rusticana, syn. Cochlearia armoracia) is a perennial plant of the family Brassicaceae (which also includes mustard, wasabi, broccoli, and cabbage). It is a root vegetable used as a spice and prepared as a condiment.
The plant is probably native to southeastern Europe and western Asia. It is popular worldwide. It grows up to Template:Convert tall, and is cultivated primarily for its large, white, tapered root.<ref>Flora of North America, Armoracia rusticana P. Gaertner, B. Meyer & Scherbius, Oekon. Fl. Wetterau. 2: 426. 1800</ref><ref>Flora of China, 辣根 la gen Armoracia rusticana P. Gaertner et al.</ref><ref>Altervista Flora Italiana, Rafano rusticano, Meerrettich, Armoracia rusticana P. Gaertn., B. Mey. & Scherb. includes photos and European distribution map</ref><ref>Biota of North America Program 2014 county distribution map</ref>
The intact horseradish root has hardly any aroma. When cut or grated enzymes from the now-broken plant cells break down sinigrin (a glucosinolate) to produce allyl isothiocyanate (mustard oil), which irritates the mucous membranes of the sinuses and eyes. Grated mash should be used immediately or preserved in vinegar for best flavor. Once exposed to air or heat it will begin to lose its pungency, darken in color, and become unpleasantly bitter tasting over time.
Horseradish is probably indigenous to temperate Eastern Europe, where its Slavic name khren seemed to Augustin Pyramus de Candolle more primitive than any Western synonym. Horseradish has been cultivated since antiquity.<ref>J.W.Courter and A.M. Rhodes, "Historical notes on horseradish" Economic Botany 23.2 (April 1969), 156-164</ref> According to Greek mythology, the Delphic Oracle told Apollo that the horseradish was worth its weight in gold.<ref name=healingfoods>Template:Cite book</ref> Dioscorides listed horseradish equally as Persicon sinapi (Diosc. 2.186) or Sinapi persicum (Diosc. 2.168),<ref>Early Modern translators of Dioscurides offered various names.</ref> which Pliny's Natural History reported as Persicon napy;<ref>Pliny on Thlaspi or Persicon napy H.N. i. 37.113</ref> Cato discusses the plant in his treatises on agriculture, and a mural in Pompeii shows the plant. Horseradish 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. The early Renaissance herbalists Pietro Andrea Mattioli and John Gerard showed it under Raphanus.<ref>Template:Cite journal</ref> Its modern Linnaean genus Armoracia was first applied to it by Heinrich Bernhard Ruppius, in his Flora Jenensis, 1745, but Linnaeus himself called it Coclearia armoracia.
Both root and leaves were used as a medicine during the Middle Ages. The root was used as a condiment on meats in Germany, Scandinavia, and Britain. It was introduced to North America during European colonialization;<ref name="motherearthnews.com">Template:Cite news</ref> both George Washington and Thomas Jefferson mention horseradish in garden accounts.<ref>Ann Leighton, American Gardens in the Eighteenth Century: 'For Use or Delight' , 1976, p.431.</ref>
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: Template:Quote
The word horseradish is attested in English from the 1590s. It combines the word horse (formerly used in a figurative sense to mean strong or coarse) and the word radish.<ref name=etymonline>Template:Cite web</ref>
Horseradish is perennial in hardiness zones 2–9 and can be grown as an annual in other zones, although not as successfully as in zones with both a long growing season and winter temperatures cold enough to ensure plant dormancy. After the first frost in autumn kills the leaves, the root is dug and divided. The main root is harvested and one or more large offshoots of the main root are replanted to produce next year's crop. Horseradish left undisturbed in the garden spreads via underground shoots and can become invasive. Older roots left in the ground become woody, after which they are no longer culinarily useful, although older plants can be dug and re-divided to start new plants.<ref name="motherearthnews.com" /><ref>Template:Cite web</ref> The early season leaves can be distinctively different, asymmetric spiky, before the mature typical flat broad leaves start to be developed.
Pests and diseases
Widely introduced by accident, "cabbageworms", the larvae of Pieris rapae, the Small White butterfly, are a common caterpillar pest in horseradish. The adults are white butterflies with black spots on the forewings that are commonly seen flying around plants during the day. The caterpillars are velvety green with faint yellow stripes running lengthwise down the back and sides. Full grown caterpillars are about Template:Convert in length. They move sluggishly when prodded. They overwinter in green pupal cases. Adults start appearing in gardens after the last frost and are a problem through the remainder of the growing season. There are three to five overlapping generations a year. Mature caterpillars chew large, ragged holes in the leaves leaving the large veins intact. Handpicking is an effective control strategy in home gardens.<ref>Template:Cite web</ref>
The distinctive pungent taste of horseradish is from the compound allyl isothiocyanate. Upon crushing the flesh of horseradish, the enzyme myrosinase is released and acts on the glucosinolates sinigrin and gluconasturtiin, which are precursors to the allyl isothiocyanate. The allyl isothiocyanate serves the plant as a natural defense against herbivores. Since allyl isothiocyanate is harmful to the plant itself, it is stored in the harmless form of the glucosinolate, separate from the myrosinase enzyme. When an animal chews the plant, the allyl isothiocyanate is released, repelling the animal.<ref name=Cole /> Allyl isothiocyanate is an unstable compound, degrading over the course of days at Template:Convert.<ref>Template:Cite journal</ref> Because of this instability, horseradish sauces lack the pungency of the freshly crushed roots.
Cooks use the terms "horseradish" or "prepared horseradish" to refer to the grated root of the horseradish plant mixed with vinegar. Prepared horseradish is white to creamy-beige in color. It can be stored for months under refrigeration, but eventually will darken, indicating it is losing flavour and should be replaced. The leaves of the plant, while edible, are not commonly eaten, and are referred to as "horseradish greens", which have a flavor similar to that of the roots.
Horseradish saucevinegar is a popular condiment in the United Kingdom and in Poland.<ref>Template:Cite book</ref> In the UK, it is usually served with roast beef, often as part of a traditional Sunday roast; but can be used in a number of other dishes also, including sandwiches or salads. A variation of horseradish sauce, which in some cases may substitute the vinegar with other products like lemon juice or citric acid, is known in Germany as Tafelmeerrettich. Also popular in the UK is Tewkesbury mustard, a blend of mustard and grated horseradish originating in medieval times and mentioned by Shakespeare (Falstaff says: "his wit's as thick as Tewkesbury Mustard" in Henry IV Part II<ref>Template:Cite web</ref>). A very similar mustard, called Krensenf or Meerrettichsenf, is popular in Austria and parts of Eastern Germany.Template:Citation needed In France, sauce au raifort is popular in Alsatian cuisine.Template:Citation needed In Russia horseradish root is usually mixed with grated garlic and small amount of tomatoes for color.Template:Citation needed
In the US the term "horseradish sauce" refers to grated horseradish combined with mayonnaise or salad dressing. Prepared horseradish is a common ingredient in Bloody Mary cocktails and in cocktail sauce, and is used as a sauce or sandwich spread. Horseradish cream is a mixture of horseradish and sour cream and is served alongside au jus for a prime rib dinner.Template:Citation needed
In Central and Eastern Europe horseradish is called khren, hren and ren (in various spellings like kren) in many Slavic languages, in Austria, in parts of Germany (where the other German name Meerrettich is not used), in North-East Italy, and in Yiddish (כריין transliterated as khreyn).
There are two varieties of khreyn. "Red" khreyn is mixed with red beetroot and "white" khreyn contains no beetroot. It is popular in Ukraine (under the name of Template:Lang, khrin), in Belarus (under the name of Template:Lang, chren), in Poland (under the name of Template:Lang), in the Czech Republic (Template:Lang), in Russia (Template:Lang, khren), in Hungary (Template:Lang), in Romania (Template:Lang), in Lithuania (Template:Lang), in Bulgaria (Template:Lang, khryan), and in Slovakia (under the name of Template:Lang). Having this on the table is a part of Christian Easter and Jewish Passover tradition in Eastern and Central Europe.
- In parts of Southern Germany like Franconia, "Kren" is an essential component of the traditional wedding dinner. It is served with cooked beef and a dip made from lingonberry to balance the slight hotness of the Kren.
- In Poland, a variety with red beetroot is called Template:Lang or simply ćwikła.
- Ashkenazi European Jewish cooking beetroot horseradish is commonly served with gefilte fish.
- In Transylvania and other Romanian regions, Red beetroot with horseradish is also used as a salad served with lamb dishes at Easter called sfecla cu hrean.
- In Serbia, ren is an essential condiment with cooked meat and freshly roasted suckling pig.
- In Croatia, freshly grated horseradish (Croatian: Hren) is often eaten with boiled ham or beef.
- In Slovenia, and in the adjacent Italian regions of Friuli Venezia Giulia and nearby Italian region of Veneto, horseradish (often grated and mixed with sour cream, vinegar, hard-boiled eggs, or apples) is also a traditional Easter dish.
- Further west in the Italian regions of Lombardy, Emilia-Romagna, and Piedmont, it is called "barbaforte (strong beard)" and is a traditional accompaniment to bollito misto; while in north-eastern regions like Trentino-Alto Adige/Südtirol,<ref>Giambattista Azzolini, Vocabolario vernacolo-italiano pei distretti roveretano e trentino, Venezia, Tip. e calc. di Giuseppe Grimaldo, 1856, p. 120.</ref> Veneto<ref>Giuseppe Boerio, Dizionario del dialetto veneziano, 3rd edition, Venezia, Reale tipografia di Giovanni Cecchini edit., 1867, p. 207.</ref> and Friuli-Venezia Giulia,<ref>Rafano rusticano in www.friul.net.</ref><ref>Jacopo Pirona, Vocabolario friulano, Venezia, coi tipi dello stabilimento Antonelli, 1871, p. 490.</ref> it is still called "kren" or "cren". In the southern region of Basilicata it is known as "rafano" and used for the preparation of the so-called "rafanata", a main course made of horseradish, eggs, cheese and sausage.<ref>Template:Cite book</ref>
- Horseradish is also used as a main ingredient for soups. In the Polish region of Silesia, horseradish soup is a common Easter Day dish.<ref>Template:Cite web</ref>
Relation to wasabi
The Japanese condiment wasabi, although traditionally prepared from the true wasabi plant (Wasabia japonica), is now usually made with horseradish due to the scarcity of the wasabi plant.<ref>Template:Cite journal</ref> The Japanese botanical name for horseradish is Template:Nihongo, or "Western wasabi". Both plants are members of the family Brassicaceae.
In a 100 gram amount, prepared horseradish provides 48 calories and has high content of vitamin C with moderate content of sodium, folate and dietary fiber, while other essential nutrients are negligible in content.<ref name="nd">Template:Cite web</ref> In a typical serving of one tablespoon (15 grams), horseradish supplies no significant nutrient content.<ref name=nd/>
The enzyme horseradish peroxidase (HRP), found in the plant, is used extensively in molecular biology and biochemistry primarily for its ability to amplify a weak signal and increase detectability of a target molecule.<ref>Template:Cite journal</ref> HRP has been used in decades of research to visualize under microscopy and assess non-quantitatively the permeability of capillaries, particularly those of the brain.<ref>Template:Cite journal</ref>
- International Horseradish Festival
- Horseradish Information Council
- Herb Society of America Herb of the Year 2011
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