The name kale originates from Northern Middle Englishcale (compare Scotskail and German Kohl) for various cabbages. The ultimate origin is Latincaulis 'cabbage'.[1][2]
Derived from wild mustard,[3] kale is considered to be closer to wild cabbage than most domesticated forms of B. oleracea.[4]
Kale is usually a biennial plant grown from seed with a wide range of germination temperatures.[5] It is hardy and thrives in wintertime,[5] and can survive in temperatures as low as −15 °C (5 °F).[6] Kale can become sweeter after a heavy frost.[7]
Children collecting leaves of red Russian kale (Brassica napus L. subsp. napus var. pabularia (DC.) Alef.) in a family vegetable garden
Kale originated in the eastern Mediterranean and Anatolia, where it was cultivated for food beginning by 2000 BCE at the latest.[8] Curly-leaved varieties of cabbage already existed along with flat-leaved varieties in Greece in the 4th century BC. These forms, which were referred to by the RomansasSabellian 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.[8] Records in 14th-century England distinguish between hard-heading cabbage and loose-leaf kale.[8]
Russian traders introduced Russian kale into Canada and then into the United States in the 19th century.[8]USDA botanist David Fairchild is credited with introducing kale (and many other crops) to Americans,[9][10] having brought it back from Croatia,[10] although Fairchild himself disliked cabbages, including kale.[10] At the time, kale was widely grown in Croatia mostly because it was easy to grow and inexpensive, and could desalinate soil.[10]
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)
Sparkly-leaf (shiny and glossy)
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 in white and lavender
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 kaleorcow cabbage.[11]Kai-lanorChinese 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).[12]
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.[13]Ornamental kale is as edible as any other variety, but potentially not as palatable.[verification needed][14] Kale leaves are increasingly used as an ingredient for vegetable bouquets and wedding bouquets.[15]
Boiling kale decreases the level of glucosinate compounds, whereas steaming, microwaving, or stir frying does not cause significant loss.[21] Kale is high in oxalic acid, the levels of which can be reduced by cooking.[22]
In the Netherlands, a traditional winter dish called "boerenkoolstamppot" is a mix of curly kale and mashed potatoes, sometimes with fried bacon, and served with rookworst ("smoked sausage").[26]
InNorthern Germany, 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 ("kale sausage").[27] Kale is considered a Northern German staple and comfort food.[28]
A traditional Portuguese soup, caldo verde, combines pureed potatoes, very finely sliced kale, olive oil and salt.[30] Additional ingredients can include broth and sliced, cooked spicy sausage.
In Scotland, kale provided such a base for a traditional diet that the word in some Scots dialects is synonymous with food. To be "off one's kail" is to feel too ill to eat.[31]
In Ireland, kale is mixed with mashed potatoes to make the traditional dish colcannon.[32] It is popular on Halloween,[33] when it may be served with sausages.
In the United Kingdom, the cultivation of kale (and other vegetables) was encouraged during World War II via the Dig for Victory campaign.[34] The vegetable was easy to grow and provided important nutrients missing from a diet because of rationing.[35]
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.
For most of the 20th century, kale was primarily used in the U.S. for decorative purposes; it became more popular as an edible vegetable in the 1990s due to its nutritional value.[10]
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').[36] In Cuthbertson's book Autumn in Kyle and the charm of Cunninghame, he states that KilmaursinEast 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.[37]
^ abcdPerry, Leonard. "Interesting cool crops". University of Vermont Extension, Department of Plant and Soil Science. Archived from the original on 19 June 2022. Retrieved 5 June 2018.
^ abNational Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). ISBN978-0-309-48834-1. PMID30844154. Archived from the original on 9 May 2024. Retrieved 21 June 2024.
^Walsh RP, Bartlett H, Eperjesi F (2015). "Variation in Carotenoid Content of Kale and Other Vegetables: A Review of Pre- and Post-harvest Effects". J Agric Food Chem. 63 (28 Oct): 9677–82. doi:10.1021/acs.jafc.5b03691. PMID26477753.
^Kushad MM, Brown AF, Kurilich AC, Juvik JA, Klein BP, Wallig MA, Jeffery EH (1999). "Variation of glucosinolates in vegetable crops of Brassica oleracea". J Agric Food Chem. 47 (4): 1541–8. doi:10.1021/jf980985s. PMID10564014.
^Nugrahedi, P. Y.; Verkerk, R; Widianarko, B; Dekker, M (2015). "A mechanistic perspective on process-induced changes in glucosinolate content in Brassica vegetables: A review". Critical Reviews in Food Science and Nutrition. 55 (6): 823–38. doi:10.1080/10408398.2012.688076. PMID24915330. S2CID25728864.
^Armesto, Jorge; Gómez-Limia, Lucía; Carballo, Javier; Martínez, Sidonia (23 July 2018). "Effects of different cooking methods on the antioxidant capacity and flavonoid, organic acid and mineral contents of Galega kale (Brassica oleracea var. acephala cv. Galega)". International Journal of Food Sciences and Nutrition. 70 (2): 136–149. doi:10.1080/09637486.2018.1482530. ISSN0963-7486. PMID30037287. S2CID51712893.
^Korus, Anna; Lisiewska, Zofia (2011). "Effect of preliminary processing and method of preservation on the content of selected antioxidative compounds in kale (Brassica oleracea L. var. acephala) leaves". Food Chemistry. 129 (1): 149–154. doi:10.1016/j.foodchem.2011.04.048.
^Zietz, Michaela; Weckmüller, Annika; Schmidt, Susanne; Rohn, Sascha; Schreiner, Monika; Krumbein, A; Kroh, Lothar W (2010). "Genotypic and Climatic Influence on the Antioxidant Activity of Flavonoids in Kale (Brassica oleracea var. sabellica)". Journal of Agricultural and Food Chemistry. 58 (4): 2123–2130. doi:10.1021/jf9033909. PMID20095605.
