Kale (), or leaf cabbage, belongs to a group of cabbage (''

Brassica oleracea ''Brassica oleracea'' is a plant species from family Brassicaceae that includes many common cultivars used as vegetables, such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy cabbage, kohlrabi, and gai lan. Its ...

'')

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s grown for their

edible leaves This is a list of vegetables which are grown or harvested primarily for the consumption of their leafy parts, either raw or cooked. Many vegetables with leaves that are consumed in small quantities as a spice such as oregano, for medicinal purpo ...

, although some are used as ornamentals. Kale plants have green or purple leaves, and the central leaves do not form a head (as with

headed cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nbs ...

). Kales are considered to be closer to wild cabbage than most of the many domesticated forms of ''Brassica oleracea''.

Etymology

''Kale'' originates from Northern

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English p ...

''cale'' (compare Scots ''kail'' and German ''Kohl'') for various

cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nb ...

s. The ultimate origin is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''caulis'' 'cabbage'.

History

Kale originated in the eastern Mediterranean and

Anatolia Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The re ...

, where it was cultivated for food beginning by 2000 BCE at the latest. Curly-leaved varieties of cabbage already existed along with flat-leaved varieties in

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...

in the 4th century BC. These forms, which were referred to by the Romans as Sabellian kale, are considered to be the ancestors of modern kales. The earliest record of cabbages in western Europe is of hard-heading cabbage in the 13th century. Records in 14th-century England distinguish between hard-heading cabbage and loose-leaf kale. Russian traders introduced Russian kale into Canada and then into the United States in the 19th century.

USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

David Fairchild is credited with introducing kale (and many other crops) to Americans, having brought it back from

Croatia , image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = "Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capit ...

, although Fairchild himself disliked cabbages, including kale. At the time, kale was widely grown in Croatia mostly because it was easy to grow and inexpensive, and could desalinate soil. For most of the twentieth century, kale was primarily used in the United States for decorative purposes; it became more popular as an edible vegetable in the 1990s due to its nutritional value. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, the cultivation of kale (and other vegetables) in the U.K. was encouraged by the

Dig for Victory Victory gardens, also called war gardens or food gardens for defense, were vegetable, fruit, and herb gardens planted at private residences and public parks in the United States, United Kingdom, Canada, Australia and Germany during World War I ...

campaign. The vegetable was easy to grow and provided important nutrients missing from a diet because of rationing.

Cultivation

Kale is usually an

annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...

grown from seed with a wide range of

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

temperatures. It is

hardy Hardy may refer to: People * Hardy (surname) * Hardy (given name) * Hardy (singer), American singer-songwriter Places Antarctica * Mount Hardy, Enderby Land * Hardy Cove, Greenwich Island * Hardy Rocks, Biscoe Islands Australia * Hardy, Sout ...

and thrives in wintertime, and can survive in temperatures as low as –15.0° Celsius.Derek B. Munro Kale can become sweeter after a heavy frost.

Cultivars

One may differentiate between kale varieties according to the low, intermediate, or high length of the stem, along with the variety of leaf types. The leaf colours range from light green to green, dark green, violet-green, and violet-brown. Classification by leaf type: * Curly-leaf (Scots kale, blue curled kale) * Bumpy-leaf (black cabbage, better known by its Italian translation 'cavolo nero', and also known as Tuscan Cabbage, Tuscan Kale, lacinato and dinosaur kale) * Plain-leaf (flat-leaf types like red Russian and white Russian kale) * Leaf and spear, or feathery-type leaf (a cross between curly- and plain-leaf) *Ornamental (less palatable and tougher leaves) Ornamental Kale

Because kale can grow well into winter, one variety of ''rape kale'' is called "'' hungry gap"'' after the period in winter in traditional agriculture when little else could be harvested. An extra-tall variety is known as '' Jersey kale'' or ''cow cabbage''. ''

Kai-lan Gai lan, kai-lan, Chinese broccoli, Chinese kale, or jie lan (''Brassica oleracea'' var. ''alboglabra'') is a leaf vegetable with thick, flat, glossy blue-green leaves with thick stems, and florets similar to (but much smaller than) broccoli. ...

'' or ''Chinese kale'' is a cultivar often used in Chinese cuisine. In Portugal, the bumpy-leaved kale is mostly called "couve galega" (Galician kale or Portuguese Cabbage).

Ornamental kale

Many varieties of kale and cabbage are grown mainly for ornamental leaves that are brilliant white, red, pink, lavender, blue, or violet in the interior of the rosette. The different types of ornamental kale are peacock kale, coral prince, kamone coral queen, color up kale, and chidori kale. ''Ornamental kale'' is as edible as any other variety, but potentially not as

palatable Palatability (or palatableness) is the hedonic reward (i.e., pleasure) provided by foods or fluids that are agreeable to the "palate", which often varies relative to the homeostatic satisfaction of nutritional, water, or energy needs. The palatabi ...

. Kale leaves are increasingly used as an ingredient for

vegetable bouquet A vegetable bouquet is a collection of vegetables in a creative arrangement. Vegetable bouquets are often considered as an alternative to flower bouquets. Vegetable bouquets can be handheld or can be used for the interior decoration. They are often ...

s and

wedding bouquet A flower bouquet is a collection of flowers in a creative arrangement. Flower bouquets can be arranged for the decor of homes or public buildings, or may be handheld. Handheld bouquets are classified by several different popular shapes and style ...

Nutritional value

Raw kale is composed of 84% water, 9%

carbohydrates In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...

, 4%

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

, and 1%

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers spec ...

(table). In a serving, raw kale provides of food energy and a large amount of

vitamin K Vitamin K refers to structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulation ...

at 3.7 times the Daily Value (DV) (table). It is a rich source (20% or more of the DV) of

vitamin A Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably bet ...

vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...

vitamin B6 Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosphat ...

, folate, and

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

(see table "Kale, raw"). Kale is a good source (10–19% DV) of thiamin,

riboflavin Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in ...

, pantothenic acid,

vitamin E Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitami ...

, and several dietary minerals, including

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...

, and

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

(see table "Kale, raw"). Boiling raw kale diminishes most of these nutrients, while values for vitamins A, C, and K and manganese remain substantial (see table "Kale, cooked").

Phytochemicals

Kale is a source of the

carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic compound, organic pigments that are produced by plants and algae, as well as several bacteria, and Fungus, fungi. Carotenoids give the characteristic color to pumpki ...

lutein Lutein (;"Lutein"

zeaxanthin Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle. Synthesized in plants and some micro-organisms, it is the pigment that gives paprika (made from bell peppers), corn, saffron, goji ( wolfberries), ...

(tables). As with broccoli and other cruciferous vegetables, kale contains

glucosinolate Glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. T ...

compounds, such as

glucoraphanin Glucoraphanin is a glucosinolate found in broccoli, mustard and other cruciferous vegetables. Glucoraphanin is converted to sulforaphane by the enzyme myrosinase. In plants, sulforaphane deters insect predators and acts as a selective antibioti ...

, which contributes to the formation of

sulforaphane Sulforaphane (sometimes sulphoraphane in British English) is a compound within the isothiocyanate group of organosulfur compounds. It is produced when the enzyme myrosinase transforms glucoraphanin, a glucosinolate, into sulforaphane upon damage ...

, a compound under preliminary research for its potential to affect human health beneficially. Boiling kale decreases the level of glucosinate compounds, whereas

steaming Steaming is a method of cooking using steam. This is often done with a food steamer, a kitchen appliance made specifically to cook food with steam, but food can also be steamed in a wok. In the American southwest, steam pits used for cooking ha ...

, microwaving, or

stir frying Stir frying () is a cooking technique in which ingredients are fried in a small amount of very hot oil while being stirred or tossed in a wok. The technique originated in China and in recent centuries has spread into other parts of Asia and th ...

does not cause significant loss. Kale is high in

oxalic acid Oxalic acid is an organic acid with the systematic name ethanedioic acid and formula . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name comes from the fact that early inve ...

, the levels of which can be reduced by cooking. Kale contains high levels of polyphenols, such as ferulic acid, with levels varying due to environmental and genetic factors.

Culinary uses

As a snack product

Flavored "kale chips" have been produced as a potato chip substitute.

Regional uses

Europe

In the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

, a traditional winter dish called " boerenkoolstamppot" is a mix of curly kale and mashed potatoes, sometimes with fried bacon, and served with

rookworst The Rookworst (; smoked sausage) is a type of Dutch sausage in which ground meat is mixed with spices and salt and stuffed into a casing (originally made of intestine, but these days usually made of bovine collagen). Described as a Bologna-type ...

("smoked sausage"). In

Northern Germany Northern Germany (german: link=no, Norddeutschland) is a linguistic, geographic, socio-cultural and historic region in the northern part of Germany which includes the coastal states of Schleswig-Holstein, Mecklenburg-Vorpommern and Lower Saxony an ...

, there is a winter tradition known as " Kohlfahrt" ("kale trip"), where a group of people will go on a hike through the woods during the day before gathering at an inn or private residence where kale is served, usually with bacon and

Kohlwurst Kohlwurst, Lungenwurst or Lungwurst is a simple, fresh, strongly smoked sausage (''Rohwurst'') made of lights, pork and fat, which is mostly eaten cooked with kale (cabbage) dishes such as '' Knieperkohl''. It is mainly used in Northeast and Nor ...

("kale sausage"). Kale is considered a Northern German staple and

comfort food Comfort food is food that provides a nostalgic or sentimental value to someone, and may be characterized by its high caloric nature, high carbohydrate level, or simple preparation. The nostalgia may be specific to an individual, or it may app ...

. In Italy,

cavolo nero Lacinato kale (, ) or, in Italian and often in English, (, ; literally "black cabbage") is a variety of kale with a long tradition in Italian cuisine, especially that of Tuscany. It is also known as Tuscan kale, Italian kale, dinosaur kale, k ...

kale is an ingredient of the Tuscan soup

ribollita Ribollita is a Tuscan bread soup, panade, porridge, or potage made with bread and vegetables, often from leftovers. There are many variations but the main ingredients always include leftover bread, cannellini beans, lacinato kale, cabbage, a ...

. A traditional Portuguese soup, '' caldo verde'', combines pureed potatoes, very finely sliced kale,

olive oil Olive oil is a liquid fat obtained from olives (the fruit of ''Olea europaea''; family Oleaceae), a traditional tree crop of the Mediterranean Basin, produced by pressing whole olives and extracting the oil. It is commonly used in cooking: f ...

and salt. Additional ingredients can include broth and sliced, cooked spicy

sausage A sausage is a type of meat product usually made from ground meat—often pork, beef, or poultry—along with salt, spices and other flavourings. Other ingredients, such as grains or breadcrumbs may be included as fillers or extenders. ...

. In Scotland, kale provided such a base for a traditional diet that the word in some

Scots dialects Scots usually refers to something of, from, or related to Scotland, including: * Scots language, a language of the West Germanic language family native to Scotland * Scots people, a nation and ethnic group native to Scotland * Scoti, a Latin name ...

is synonymous with food. To be "off one's kail" is to feel too ill to eat. In Ireland, kale is mixed with mashed potatoes to make the traditional dish ''

colcannon Colcannon () is a traditional Irish dish of mashed potatoes with cabbage or kale. Description Colcannon is most commonly made with only four ingredients: potatoes, butter, milk and cabbage (or kale). Irish historian Patrick Weston Joyce defined ...

''. It is popular on

Halloween Halloween or Hallowe'en (less commonly known as Allhalloween, All Hallows' Eve, or All Saints' Eve) is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Saints' Day. It begins the observanc ...

, when it may be served with sausages.

Asia

In Sri Lanka, it is known as ''kola gova'' or ela gova. It is cultivated for edible use. A dish called 'kale mallung' is served almost everywhere on the island, along with rice.

In literature

The ''Kailyard'' school of Scottish writers, which included J. M. Barrie (creator of Peter Pan), consisted of authors who wrote about traditional rural Scottish life (''kailyard'' = 'kale field'). In Cuthbertson's book ''Autumn in Kyle and the charm of Cunninghame'', he states that Kilmaurs in East Ayrshire was famous for its kale, which was an important foodstuff. A story is told in which a neighbouring village offered to pay a generous price for some kale seeds, an offer too good to turn down. The locals agreed, but a gentle roasting on a shovel over a coal fire ensured the seeds never germinated.Cuthbertson, David Cuningham (1945). ''Autumn in Kyle and the Charm of Cunninghame''. London: Jenkins. Page 186

Gallery

File:Kale-Bundle.jpg, Curly-leaf kale File:CSA-Red-Russian-Kale.jpg, Red Russian kale File:20170526-AMS-LSC-0326 (34137217614).jpg,

Tuscan kale Lacinato kale (, ) or, in Italian and often in English, (, ; literally "black cabbage") is a variety of kale with a long tradition in Italian cuisine, especially that of Tuscany. It is also known as Tuscan kale, Italian kale, dinosaur kale, k ...

File:Making kale chips in Lockport, Illinois.jpg, Making

kale chips Kale (), or leaf cabbage, belongs to a group of cabbage (''Brassica oleracea'') cultivars grown for their edible leaves, although some are used as ornamentals. Kale plants have green or purple leaves, and the central leaves do not form a head ...

in Illinois File:Kogt skinke brunede kartofler grønlangkål.jpg, A traditional

New Years New Year is the time or day currently at which a new calendar year begins and the calendar's year count increments by one. Many cultures celebrate the event in some manner. In the Gregorian calendar, the most widely used calendar system tod ...

Danish dish: boiled ham, glazed potatoes and stewed kale File:Vegan Stack at Two Mountains (cropped).jpg, A kale-based dish with other vegetables and

sourdough bread Sourdough or sourdough bread is a bread made by the fermentation of dough using wild lactobacillaceae and yeast. Lactic acid from fermentation imparts a sour taste and improves keeping qualities. History In the ''Encyclopedia of Food Microbiolo ...

, served at a restaurant in Australia

References

External links

Marrow-Stem Kale
– Plants for a Future database
PROTAbase on ''Brassica oleracea'' (leaf cabbage)
{{Authority control Brassica oleracea Leaf vegetables