Suppression

Kale

Category: Food

Type

Voluntary

Introduction and description

 

 

Kale or borecole is a vegetable of the plant species Brassica oleracea.  It is thus classified as a brassicaBrassica oleracea includes many common foods as cultivars, including cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, savoy, kohlrabi and kai-lan.

Kale and collard greens belong to the Brassica oleracea Acephala Group.  The acephala group refers to any type of Brassica which grows without the central 'head' typical of many varieties of cabbage.  Kale is closer to wild cabbage than most domesticated forms of vegetable. 

The name borecole originates from the Dutch boerenkool (farmer's cabbage), whereas kale bears semblance to the Danish, Swedish and Norwegian kål and to the German Kohl (a general term for various kinds of cabbage) and Scottish Gaelic càl, or kail, as in Kilmany Kail; a rabbit, salt pork and kail broth from Kilmany in Perth, Scotland.

Kale Komone red flowering - for flower borders and
it can be eaten

Kale makes a delicious vegetable and it is very hardy, but it is also extremely rich in minerals and vitamins.

The nutritional value of kale was once well known. During World War II, the cultivation of kale in the U.K. was encouraged by the Dig for Victory campaign. The vegetable was easy to grow and provided important nutrients to supplement those missing from a normal diet because of rationing.

It is medicinally very useful, especially for those with skin problems and heart problems.  A useful plant that has somehow fallen out of favour and needs to be revived!

Distribution

Until the end of the Middle Ages, kale was one of the most common green vegetables in Europe. Curly-leaved varieties of cabbage already existed along with flat-leaved varieties in Greece in the fourth century BC.  These forms, which were referred to by the Romans as Sabellian kale, are considered to be the ancestors of modern kales.

Since then the number of varieties of kale has increased and the plant is now grown worldwide in those countries with a cooler climate.  Russian kale, for example, was introduced into Canada (and then into the U.S.) by Russian traders in the 19th century.

Description and types

 

There are a number of different varieties of kale, some purple and some green, some with very curly leaves [known as curly kale] and some with straight leaves. Some varieties can reach a height of six or seven feet; others are compact and symmetrical and of good quality for eating. There are some that are purely ornamental and very beautiful.  They are edible, but are rather bitter.

Today one may differentiate between varieties according to the low, intermediate, or high length of the stem, with varying leaf types. The leaf colours range from light green through green, dark green and violet-green to violet-brown.

The 'Jersey cabbage'

The Jersey cabbage or kale

is a giant variety, once grown all over the island of Jersey, but now rarely seen. The stem grows tall and straight and if cut, dried and varnished it makes an excellent walking stick. These sticks were popular souvenirs for holidaymakers, with an enamelled Jersey penny set into the head, and some are still made to this day. 

This variety of kale has a lot of alternative names - giant Jersey cabbage, long jack, walking-stick cabbage, cow cabbage, Jérriais lé grand chour à vaque [i.e., big cabbage for cows], Jérriais lé chour [i.e., cabbage], tree cabbage, or Jersey kale, or Brassica oleracea longata.

Cavolo Nero

Lacinato kale (called cavolo nero, literally "black kale", in Italian and often in English) is a variety of kale with a long tradition in Italian cuisine, especially that of Tuscany.

Cavolo nero

It is also known as Tuscan kale, Tuscan cabbage, Italian kale, dinosaur kale, black kale, flat back cabbage, palm tree kale, or black Tuscan palm. Lacinato kale has been grown in Tuscany for centuries, and is one of the traditional ingredients of minestrone and ribollita. 
Cavolo Nero is also delicious stir fried in olive oil with fennel seeds and sea salt, for example.  The stalk can be tough and the leaves are snipped off the stem with scissors before stir frying.    Despite being used in Italy, it is just as hardy as the other kales and can withstand heavy frosts and being covered by several feet of snow [as we can testify].

Kai-lan

A separate cultivar of Brassica oleracea much used in Chinese cuisine, is somewhat similar to kale in appearance and is occasionally called "kale" in English.  Kai-lan, is a popular vegetable in China, Taiwan, and Vietnam, where it is commonly combined with beef dishes.

Curly kale

Curly kale - Brassica oleracea sabellica is a biennial or perennial growing to 0.9 m (3ft).
It is hardy - so not frost tender. The plant is grown for its leaves which can be eaten raw when very young and cooked as they grow older.   The leaves are usually available from autumn to late spring, and can be harvested all through the winter in all but the very coldest of seasons.  The young flowering shoots can also be eaten - raw or cooked. Picked before the flowers open, they are fairly tender and can be used as part of a mixed salad. When cooked, they have a delicious flavour similar to sprouting broccoli

 Daubenton’s kale

Brassica oleracea var ramosa is a perennial vegetable that seems to have everything going for it: tasty, hardy, productive and easy to grow.  It is a perennial kale that usually lives for 5 or 6 years, although it is a big plant and needs lots of room to live this long. 

Daubenton’s kale

In winter the leaves become sweeter and tenderer, and can be used in winter salads. They are also ideal for kale chips (see below).  Daubenton’s kale was named after the great French naturalist Jean-Louis-Marie Daubenton, a man who has had to suffer the posthumous indignity of English speakers constantly sticking an apostrophe into his name in order to make it look more French, so you’ll often find the plant referred to as D’Aubenton’s kale or even chou D’Aubenton.  The bargain that Daubenton’s makes for its long life is that it is lived in complete celibacy. It is hardly ever known to flower, which means that it doesn’t exhaust itself, but adds a problem for the gardener: no flowers means no seeds, perhaps giving one reason why it is so rare. Fortunately, it is extremely easy to propagate from stem cuttings, particularly if you break off branches near the base. You’ll find some knobbles which are incipient roots: plant them or put them in water at almost any time of year and they will start to grow.

Rare varieties

Pentland brig

It seems that a lot more kales used to be perennial, but Victorian seed companies selected for biennialism in order to be able to sell the same variety year on year. A few old varieties have hung on by being passed from gardener to gardener, leading to a plethora of names such as Ragged Jack, Tree collards, Woburn kale, Taunton Deane and many others which may or may not be the same as each other. Worse, some biennial varieties share a name with perennial ones having been bred from them. There is a variety of biennial kale called Pentland Brig; but also a rumour of a perennial version. In Germany there’s an ehwiger kohl (‘everlasting kale’).

 Red Russian and Siberian kale

Red Russian kale

Red Russian and Siberian kale – is thought to be a cross between Brassica rapa and Brassica oleracea. The Russo-Siberian Kales were cultivated in Northern Europe and Northern Asia, though in the past century they have been shuffled back and forth across the globe like many of our cultivated plant species. Red Russian and Siberian are the two most well known varieties in the United States, however many others have been developed from these lines.  Brassica napus is divided into three groups or subspecies

  • The Rutabaga (Swedes in England) is ssp. napobrassica or rapifera
  • Russo-Siberian Kales and Hanover Salad are ssp. pabularis or pabularia and are grown for their leaves that may resemble those of the European kales (B. oleracea).
  • Winter rape and canola, colza in India, are grown for their edible leaves, livestock forage, or for the oil rich seed.

All have large, flat leaves 12-20 in (30.5-50.8 cm) long and 8-15 in (20.3-38.1 cm) wide, stand 2-4 ft (0.6-1.2 m) when mature, have yellow, cross-shaped flowers with four petals and the small seed develops in sickle shaped pods.

Siberian kale

Despite the odd naming, Brassica napus, and classification with crops grown for their roots and seed, the Russo-Siberian kales are true kales in that they do not form a head.  The main difference between these kales and those above is that they typically have a milder flavour than the European “oleracea” kales and the young leaves can be used raw in salads. They are also used for their springtime sprouts (similar to broccoli).  Napus kales are as hardy as the other kales.  “Some varieties are hardy to -10°C and even -20°C”. I suspect that survival at these low temperatures may require good snow cover. “It is widely known that the flavor of Russo-Siberian kale sweetens dramatically after first frost. It can be grown anywhere in the US and even in Alaska”.

Cultivation

Kale and shi-itake Tom Yum

Most kale are either annuals or biennials, and are raised from seeds, which, in size, form, and colour, resemble those of the cabbage.

Kale is a  very hardy plant, tolerating temperatures down to about -15°c. It also tolerates high summer temperatures. A very easily grown plant, succeeding in full sun or partial shade [it does not like full shade] in a well-drained fertile preferably alkaline soil, kale of all sorts succeeds in any reasonable soil as long as it is not acid.  At one time, farmers used to burn lime to put on the fields to ensure the soil was more neutral or alkaline and in the UK, there are still old lime kilns by the sea shore where ships imported the lime and this took place.  Acidity results in all sorts of diseases, the nastiest of which is Clubroot. 

Clubroot is a common disease of cabbages, broccoli, cauliflower, Brussels sprouts, radishes, turnips, stocks, wallflowers and other plants belonging to the family Brassicaceae (Cruciferae). It is caused by Plasmodiophora brassicae, a fungus and once you have it, it is the very devil to get rid of.  It is pointless trying to grow any brassicas where it has appeared, as it survives year after year and continues to attack.  Thus liming your soil is ESSENTIAL.  Gall formation or distortion takes place on latent roots and gives the shape of a club or spindle. "Such attacks on the roots cause undeveloped heads or a failure to head at all, followed often by decline in vigor or by death. It is an important disease, affecting an estimated 10% of the total cultured area worldwide".  Historical reports of clubroot date back to the 13th century in Europe. In the late 19th century, a severe epidemic of clubroot destroyed large proportions of the cabbage crop in St. Petersburg

Like all brassicas, kale suffers from cabbage white butterflies, although they appear to prefer cabbages to kale.  Don't spray, if you have a vegetable garden pick them off and feed them to the birds.

My father used to grow kale from seed directly into the ground, thinning them as need be, but up here in the wilds of the north of the UK and at some height, we have found that growing the plants in tubs of good compost in a cold frame, then transferring them with all their soil helps to keep the club root away and gives them a good head start in what is a short growing season.

 Medicinal uses

 

The observations and the analysis by Dr Duke provide an extensive list of all the medicinal benefits of kale.  From a nutritional point of view, for a winter vegetable, it could not be more important being an essential source of vitamins such as Vitamin C.

 

 

USDA Nutrients Database - Full Report (All Nutrients):  11233, Kale, raw

Scientific Name:  Brassica oleracea (Acephala Group)


Nutrient

Unit

Value Per 100gms

Water 1

g

84.04

Energy

kcal

49

Energy

kJ

207

Protein 1

g

4.28

Total lipid (fat) 1

g

0.93

Ash 1

g

2.01

Carbohydrate, by difference

g

8.75

Fiber, total dietary

g

3.6

Sugars, total

g

2.26

Minerals

 

 

Calcium, Ca 1

mg

150

Iron, Fe 1

mg

1.47

Magnesium, Mg 1

mg

47

Phosphorus, P 1

mg

92

Potassium, K 1

mg

491

Sodium, Na 1

mg

38

Zinc, Zn 1

mg

0.56

Copper, Cu 1

mg

1.499

Manganese, Mn 1

mg

0.659

Selenium, Se

µg

0.9

Vitamins

 

 

Vitamin C, total ascorbic acid

mg

120.0

Thiamin

mg

0.110

Riboflavin

mg

0.130

Niacin

mg

1.000

Pantothenic acid

mg

0.091

Vitamin B-6

mg

0.271

Folate, total 1

µg

141

Folic acid

µg

0

Folate, food 1

µg

141

Folate, DFE

µg

141

Choline, total

mg

0.8

Vitamin B-12

µg

0.00

Vitamin A, RAE

µg

500

Retinol

µg

0

Carotene, beta 1 2 3

µg

5927

Carotene, alpha 1

µg

54

Cryptoxanthin, beta 1

µg

81

Vitamin A, IU

IU

9990

Lycopene 1

µg

0

Lutein + zeaxanthin 1

µg

8198

Vitamin E (alpha-tocopherol)

mg

1.54

Vitamin D (D2 + D3)

µg

0.0

Vitamin D

IU

0

Vitamin K (phylloquinone) 1

µg

704.8

Fatty acids

 

 

Fatty acids, total saturated

g

0.091

Fatty acids, total monounsaturated

g

0.052

Fatty acids, total polyunsaturated

g

0.338

Fatty acids, total trans

g

0.000

Sources of Data - see references below

 

Method

kale with garlic, ginger, chili and soy sauce

In Scotland, kale provided such a base for a traditional diet that the word in dialect Scots is synonymous with food. To be "off one's kail" is to feel too ill to eat.  Steaming kale serves to preserve a number of essential nutrients, many of which help with skin troubles, however, here are some other traditional uses:

  • Boerenkoolstamppot  - In the Netherlands, curly kale is used in a traditional winter dish called "boerenkoolstamppot", a mix of curly kale and mashed potatoes, sometimes with fried bits of bacon added to it, and usually served with rookworst ("smoked sausage").
  • Kale Concannon   - In Ireland, kale may be mixed instead of cabbage, with mashed potatoes and a lot of butter to make the traditional dish Colcannon.
  • Caldo verde - A traditional Portuguese soup, caldo verde, combines pureed potatoes, diced kale, olive oil, broth, and, generally, sliced cooked spicy sausage. In Brazil, where it was introduced by the Portuguese, it is an indispensable side dish for the national stew feijoada.
  • Italian dishes - In Italy, kale (cavolo nero) is part of many dishes, such as "casseoula" (pork stew), polenta (corn porridge) with kale, Parmesan cheese and olive oil’ and "pizzoccheri", buckwheat tagliatelle served with kale, melted fontina cheese and potatoes.
  • German kale stew - A whole culture around kale has developed in northern Germany, especially around the towns of Bremen, Oldenburg, Osnabrück and Hannover and the region of Dithmarschen. There, large quantities of kale stew, Pinkel sausage, Kassler, Mettwurst and Schnapps are consumed.
  • Langkål - Curly kale is used in Denmark and southwestern Sweden (Scania, Halland and Blekinge) to make (grøn-)langkål (Danish) or långkål (Swedish). The leaves of the kale are separated from the stem, and then boiled with stock. The result is drained and pressed to remove the remaining liquid. The kale is then finely chopped and fried with cream, pepper, and syrup (or sugar) for sweetening
  • African coconut kale - Various kale types are also eaten throughout southeastern Africa, where they are typically cooked in  coconut milk and ground peanuts and served with rice.
  • Rashtan - In Montenegro, collards, kale, locally known as rashtan, is a favourite vegetable. It is particularly popular in the winter, cooked with smoked mutton (kastradina) and potatoes.
  • Turkish dishes - In Turkey, especially in Eastern Black Sea Region, kale soup (karalahana çorbası), kale sarma, kale kavurma (sauté), kale turşu are all very common and popular dishes.

Here are some more ideas:

Kale, cabbage and carrot patties

5 cups finely shredded cabbage

2 cups finely chopped purple or curly kale

1 ½ cups peeled and grated carrots

½ cup chopped coriander

1 chili, seeded and chopped finely

Salt to taste

2 teaspoons cumin seeds, lightly toasted and coarsely ground or crushed

3 tablespoons ground almonds

3 tablespoons cornflour

2 tablespoons oatmeal

3 eggs, beaten

About 1/4 cup rice bran oil [for frying]

 

In a large bowl mix all the ingredients except the eggs and oil, when well mixed, add the eggs

Let the mixture rest for 10 to 15 minutes, then stir again.

Take 3 tablespoons of the mixture, make into a patty.  Place on a non stick surface, do all the patties this way

Heat a large heavy frying pan over medium heat. Add the oil to the pan.  When hot fry patties in batches.   Press down with a wooden spatula to flatten a bit. Cook on one side until golden brown, about three to four minutes, then flip the patties over. Cook on the other side until golden brown.

Keep warm until all the patties have been fried.

Serve hot topped with low-fat sour cream, Greek style yogurt or crème fraîche.

These go well with crispy bacon or sausages

 

 

 Sesame roasted kale

500 g kale

2 teaspoons sesame oil

1 tablespoon olive oil

1 tablespoon sesame seeds

 

Preheat the oven to 220ºC/gas 7. Rinse the kale under cold running water and dry the leaves very well, in a salad spinner if you have one. Cut out the centre stalks, then cut the kale into 5cm slices.

Place the kale on a baking tray and drizzle over the sesame and olive oils, scatter over the sesame seeds and season with sea salt and black pepper.

Roast in the oven for 20 minutes, turning halfway through cooking, until crisp at the edges.

 

 


Kale, ricotta & squash omelette

2 large free-range eggs

1 handful of fresh kale

2 tablespoons crumbled ricotta cheese

150 g cubed roasted butternut squash and sweet potato

olive oil

Parmesan cheese

 

Whisk the eggs in a large bowl.
Tear kale into pieces.  Then using a blender, chop until fine.
Add the kale and ricotta to the eggs and stir.
Mash the squash with a fork, add to the bowl.
Preheat the grill to medium-high.
Place a small non-stick frying pan on medium heat, drizzle with a little oil then pour in the mixture. Tilt the pan to spread out the mixture and form an even layer, then let it cook for 1 to 2 minutes, or until the sides start to bubble and get golden.
Grate a fine layer of Parmesan over the omelette, then pop it under the grill for 3 to 5 minutes, or until golden and cooked through.

 

 

Fried rice with kale, squash & chestnuts

200 g mixed basmati and wild rice

1 onion

1 medium squash or pumpkin cubed

1-2 fresh red chillies

150 g cooked chestnuts

2 cloves of garlic

200 g curly kale

1 bunch of flat-leaf parsley

olive oil

1 stick of cinnamon

2 cloves

 

Rinse, then cook the rice according to the packet instructions. Drain and set aside.
Peel and finely slice the onion. Finely slice the chillies, removing the seeds and pith.
Roughly chop the chestnuts, peel and finely slice the garlic and roughly chop the kale. Pick and roughly chop the parsley.
Heat a splash of oil in a large lidded frying pan over a medium heat and fry the onion for 5 minutes, until beginning to soften.
Tip in the squash or pumpkin, chillies, cinnamon and cloves, then add a splash of water. Cover and cook for 10 minutes, stirring occasionally, until the squash begins to soften.
Remove the lid, add the chestnuts and cook for another 5 minutes. Stir in the garlic, cooked rice and kale, season and cook, uncovered, for 5 minutes, until the rice has a caramelised base and the squash is cooked through.
Whack up the heat for a couple of minutes, stirring the rice and letting the bottom crisp up even more. Remove from the heat and sprinkle over the parsley.

 

Rose Carrarini’s Kale and other greens sauteed in ginger and garlic

Quick, healthy bowlfuls don’t come much better than speedily stir-fried kale on a bed of brown rice

190g brown rice
470ml water
1 tbsp olive oil
1 tsp sesame oil
3 garlic cloves, minced
1 x 2cm piece of ginger, peeled and finely sliced
1 large bunch kale, ends trimmed, coarsely chopped
½ bunch spring onions, ends trimmed, finely sliced on the diagonal
1 carrot, peeled and chopped into matchsticks
A handful mangetout, coarsely sliced diagonally
A splash of soy sauce
1 tsp honey
Toasted black and white sesame seeds, to garnish

 

1 Place the rice and water in a small pan and bring to the boil over a medium heat. Reduce the heat to medium-low, cover and simmer until the water is absorbed and the rice is tender – this should take about 40 minutes. Do not uncover; the rice must cook in the steam, so don’t let it escape. Take the pan off the heat and leave covered for 10 minutes while you cook the vegetables.

2 Heat the oils in a large pan and fry the garlic and ginger until fragrant. Add the veg and toss well. When it is starting to cook, but still crisp, add the soy sauce and honey, toss everything about and remove from the heat.

3 To serve, dish the rice up in bowls, then pile the veg on top. Sprinkle with the sesame seeds and enjoy.

References and further reading


kale beetroot and blue cheese tartlets
1Nutrient Data Laboratory, ARS, USDA National Food and Nutrient Analysis Program Wave 10j , 2006  Beltsville MD  
2F W Quackenbush Reverse phase HPLC separation of cis- and trans-carotenoids and its application to beta-carotenes in food materials , 1987 J Liq Chrom 10   pp.643-653
3J P Sweeney, A C Marsh Effect of processing on provitamin A in vegetables , 1971 J Am Diet Assoc 59   pp.238-243
4Hertog, M. G. L., Hollman, P. C. H., and Katan, M. B. Content of potentially anticarcinogenic flavonoids of 28 vegetables and fruits commonly consumed in The Netherlands. , 1992 J. Agric. Food Chem. 40   pp.2379-2383
5Huber, L. S., Hoffman-Ribani, R., and Rodriguez-Amaya, D. B. Quantitative variation in Brazilian vegetable sources of flavonols and flavones. , 2009 Food Chemistry 113   pp.1278-1282
6Lugasi, A., and Hovari, J. Flavonoid aglycons in foods of plant origin I. Vegetables , 2000 Acta Alimentaria 29   pp.345-352
7Huang, Z., Wang, B., Eaves, D. H., Shikany, J. M., and Pace, R. D. Phenolic compound profile of selected vegetables frequently consumed by African Americans in the southeast United States. , 2007 Food Chemistry 103   pp.1395-1402
8Bilyk, A., and Sapers, G. M. Distribution of quercetin and kaempferol in lettuce, kale, chive, garlic chive, leek, horseradish, red radish, and red cabbage tissues. , 1985 J. Agric. Food Chem. 33   pp.226-228
9Justesen, U., Knuthsen, P., and Leth, T. Quantitative analysis of flavonols, flavones, and flavonones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection. , 1998 J. Chromatogr. A 799   pp.101-110
10Olsen, H., Aaby, K., and Borge, G. I. Characterization and quantification of flavonoids and hydroxycinnamic acids in culry kale (Brassica oleracea L. convar. Acephala var. sabellica) by HPLC-DAD-ESI-MS. , 2009 J. Agric. Food Chem. 57   pp.2816-2825
11Horn-Ross, P. L., Barnes, S., Lee, M., Coward, L., Mandel, E., Koo, J., John, E. M., and Smith, M. Assesing phytoestrogen exposure in epidemiologic studies: development of a database (United States). , 2000 Cancer Causes and Control 11   pp.289-298

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