the Onion

From Wikipedia, the free encyclopedia

Onion
Onions
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Asparagales Family: Alliaceae Genus: Allium Species: A. cepa
Binomial name
Allium cepa L.

Onion atop a bed of lettuce in a chicken sandwich.

Onions used in salsa.

Onion fields near Elba, New York

Onions cooked in a frying pan

Onion is a term used for many plants in the genus Allium. They are known by the common name "onion" but, used without qualifiers, it usually refers to Allium cepa. Allium cepa is also known as the 'garden onion' or 'bulb' onion and 'shallot'.

Allium cepa is known only in cultivation,^[1] but related wild species occur in Central Asia. The most closely-related species include Allium vavilovii Popov & Vved. and Allium asarense R.M. Fritsch & Matin from Iran.^[2] However Zohary and Hopf warn that "there are doubts whether the vavilovii collections tested represent genuine wild material or only feral derivatives of the crop."^[3]

Contents 1 Uses 2 Historical uses 3 Medicinal properties and health benefits 4 Onions and eye irritation 5 Propagation 6 Varieties 7 Production trends 8 Onions in language 9 Notes 10 References 11 See also 12 External links

Uses

Onions, one of the oldest vegetables known to humankind, are found in a bewildering array of recipes and preparations, spanning almost the totality of the world's cultures; they are nowadays available in fresh, frozen, canned, pickled, and dehydrated forms. Onions can be used, usually chopped or sliced, in almost every type of food, including cooked foods and fresh salads, and as a spicy garnish; they are rarely eaten on their own but usually act as accompaniment to the main course. Depending on the variety, an onion can be sharp, spicy, tangy and pungent or mild and sweet.

Onions pickled in vinegar are eaten as a snack. These are often served as a side serving in fish and chip shops throughout the United Kingdom. Onions are a staple food in India, and are therefore fundamental to Indian cooking. They are commonly used as a base for curries, or made into a paste and eaten as a main course or as a side dish.

Tissue from onions is frequently used in science education to demonstrate microscope usage, because they have particularly large cells which are readily observed even at low magnifications.^[4]

Historical uses

It is thought that bulbs from the onion family have been used as a food source for millennia. In Caananite Bronze Age settlements, traces of onion remains were found alongside fig and date stones dating back to 5000 BC.^[5] Onion is native to South Asia, and is widely used in Indian cuisine.^[6] However, it is not clear if these were cultivated onions. Archaeological and literary evidence such as the Book of Numbers 11:5 suggests cultivation probably took place around two thousand years later in ancient Egypt, at the same time that leeks and garlic were cultivated. Workers who built the Egyptian pyramids may have been fed radishes and onions.^[5]

The onion is easily propagated, transported and stored. The Ancient Egyptians worshipped it,^[7] believing that its spherical shape and concentric rings symbolized eternal life. Onions were even used in Egyptian burials as evidenced by onion traces being found in the eye sockets of Ramesses IV. They believed that if buried with the dead, the strong scent of onions would bring breath back to the dead.

In ancient Greece, athletes ate large quantities of onion because it was believed that it would lighten the balance of blood. Roman gladiators were rubbed down with onion to firm up their muscles. In the Middle Ages onions were such an important food that people would pay for their rent with onions and even give them as gifts.^[7] Doctors were known to prescribe onions to facilitate bowel movements and erection, and also to relieve headaches, coughs, snakebite and hair loss. The onion was introduced to North America by Christopher Columbus on his 1492 expedition to Haiti. Onions were also prescribed by doctors in the early 1500s to help with infertility in women, and even dogs and cattle and many other household pets. However, recent evidence has proven that dogs, cats, and other animals should NOT be given onions in any form, due to toxicity during digestion. ^[8]

Medicinal properties and health benefits

Raw Onions Nutritional value per 100 g (3.5 oz)
Energy 40 kcal 170 kJ
Carbohydrates 9.34 g - Sugars 4.24 g - Dietary fiber 1.7 g Fat 0.1 g - saturated 0.042 g - monounsaturated 0.013 g - polyunsaturated 0.017 g Protein 1.1 g Water 89.11 g Vitamin A equiv. 0 μg 0% Thiamin (Vit. B1) 0.046 mg 4% Riboflavin (Vit. B2) 0.027 mg 2% Niacin (Vit. B3) 0.116 mg 1% Vitamin B6 0.12 mg 9% Folate (Vit. B9) 19 μg 5% Vitamin B12 0 μg 0% Vitamin C 7.4 mg 12% Vitamin E 0.02 mg 0% Vitamin K 0.4 μg 0% Calcium 23 mg 2% Iron 0.21 mg 2% Magnesium 0.129 mg 0% Phosphorus 29 mg 4% Potassium 146 mg 3% Sodium 4 mg 0% Zinc 0.17 mg 2%
Percentages are relative to US recommendations for adults. Source: USDA Nutrient database

Wide-ranging claims have been made for the effectiveness of onions against conditions ranging from the common cold to heart disease, diabetes, osteoporosis, and other diseases.^[9] They contain chemical compounds believed to have anti-inflammatory, anticholesterol, anticancer, and antioxidant properties such as quercetin. However, it has not been demonstrated that increased consumption of onions is directly linked to health benefits.

In many parts of the world, onions are used to heal blisters and boils. A traditional Maltese remedy for sea urchin wounds is to tie half a baked onion to the afflicted area overnight. In the morning, the spikes will be in the onion.^{[citation needed]} In the United States, products that contain onion extract are used in the treatment of topical scars; some studies have found their action to be ineffective, ^[10][11][12] while others found that they may act as an anti-inflammatory or bacteriostatic ^[13] and can improve collagen organization in rabbits.^[14]

Onions may be especially beneficial for women,^[15] who are at increased risk for osteoporosis as they go through menopause, by destroying osteoclasts so that they do not break down bone.

Onions and eye irritation

As onions are sliced, cells are broken, allowing enzymes called alliinases to break down amino acid sulphoxides and generate sulphenic acids. Sulphenic acids are unstable and spontaneously rearrange into a volatile gas called syn-propanethial-S-oxide. The gas diffuses through the air and eventually reaches the eye, where it reacts with the water to form a diluted solution of sulphuric acid. This acid irritates the nerve endings in the eye, making them sting. Tear glands produce tears to dilute and flush out the irritant.^[16]

Supplying ample water to the reaction while peeling onions prevents the gas from reaching the eyes. Eye irritation can, therefore, be avoided by cutting onions under running water or submerged in a basin of water. Rinsing the onion and leaving it wet while chopping may also be effective. Another way to avoid irritation is by not cutting off the root of the onion, or by doing it last, as the root of the onion has a higher concentration of enzymes.^[17] Using a sharp blade to chop onions will limit the cell damage and the release of enzymes that drive the irritation response. Chilling or freezing onions prevents the enzymes from activating, limiting the amount of gas generated. Having a fire, such as a candle or a burner, will help as the heat and flames will draw in the onion gas, burn it, and then send it up with the rest of the flame exhaust. In the heat, the chemical changes such that it no longer irritates the eyes. The volume of sulfenic acids released, and the irritation effect, differs among Allium species.

On January 31, 2008, the New Zealand Crop and Food institute led by Colin Eady created 'no tears' onions by using Australian gene-silencing biotechnology.^[18]

Propagation

Onion and shallot output in 2005

Onion growing shoots

Onions may be grown from seed or, more commonly today, from sets started from seed the previous year. Onion sets are produced by sowing seed very thickly one year, resulting in stunted plants which produce very small bulbs. These bulbs are very easy to set out and grow into mature bulbs the following year, but they have the reputation of producing a less durable bulb than onions grown directly from seed and thinned.

Seed-bearing onions are day-length sensitive; their bulbs begin growing only after the number of daylight hours has surpassed some minimal quantity. Most traditional European onions are what is referred to as "long-day" onions, producing bulbs only after 15+ hours of daylight occur. Southern European and north African varieties are often known as "intermediate day" types, requiring only 12-13 hours of daylight to stimulate bulb formation. Finally, "short-day" onions, which have been developed in more recent times, are planted in mild-winter areas in the fall and form bulbs in the early spring, requiring only 9-10 hours of sunlight to stimulate bulb formation.

Either planting method may be used to produce spring onions or green onions, which are the leaves and/or immature plants. Green onion is a name also used to refer to another species, Allium fistulosum, the Welsh onion, which is said not to produce dry bulbs.

Varieties

Brown and white onions

Yellow Onions

Flower head of a yellow onion

Red onions

• Bulb onion - Grown from seed (or onion sets), bulb onions range from the pungent varieties used for dried soups and onion powder to the mild and hearty sweet onions, such as the Vidalia from Georgia or Walla Walla from Washington that can be sliced and eaten on a sandwich instead of meat.
• Multiplier onions - Raised from bulbs which produce multiple shoots, each of which forms a bulb.
  • Potato onion
• Tree onion or Egyptian onion - Produce bulblets in the flower head; a hybrid of Allium cepas.
• Welsh onion or Green onion
  • Leek

Shallots and ten other onion (Allium cepa L.) varieties commonly available in the United States were evaluated: Western Yellow, Northern Red, New York Bold, Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia. In general, the most pungent onions delivered many times the benefits of their milder cousins.^[19]

Shallots have the most phenols, six times the amount found in Vidalia onion, the variety with the lowest phenolic content. Shallots also have the most antioxidant activity, followed by Western Yellow, New York Bold, Northern Red, Mexico, Empire Sweet, Western White, Peruvian Sweet, Texas 1015, Imperial Valley Sweet, and Vidalia. Western Yellow onions have the most flavonoids, eleven times the amount found in Western White, the variety with the lowest flavonoid content.

For all varieties of onions, the more phenols and flavonoids they contain, the more antioxidant and anti-cancer activity they provide. When tested against liver and colon cancer cells, Western Yellow, New York Bold and shallots were most effective in inhibiting their growth. The milder-tasting varieties—Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia—showed little cancer-fighting ability.^[19]

Notes

1. ^ "Allium cepa Linnaeus". Flora of North America.
2. ^ Grubben, G.J.H. & Denton, O.A. (2004) Plant Resources of Tropical Africa 2. Vegetables. PROTA Foundation, Wageningen; Backhuys, Leiden; CTA, Wageningen.
3. ^ Daniel Zohary and Maria Hopf, Domestication of plants in the Old World, third edition (Oxford: University Press, 2000), p. 198
4. ^ "Genetics Teaching Vignettes: Elementary School" (html) (2004-06-15). Retrieved on 2008-01-28.
5. ^ ^{a b} "Onions Allium cepa". selfsufficientish.com. Retrieved on 2006-04-02.
6. ^ Sen 2004: 58
7. ^ ^{a b} "About Onions: History". Retrieved on 2008-01-30.
8. ^ "Human Foods that Poison Pets". Retrieved on 2008-01-30.
9. ^ World's Healthiest Foods
10. ^ Product Review: Mederma for Scars
11. ^ Topical scar modification: Hype or help?. (Aesthetic Surgery Journal)
12. ^ Zurada JM, Kriegel D, Davis IC (2006). "Topical treatments for hypertrophic scars.". Journal of the American Academy of Dermatology 55 (6): 1024–1031. doi:10.1016/j.jaad.2006.03.022. PMID 17097399.
13. ^ K. Augusti, Therapeutic values of onion (Allium cepa L.) and garlic (Allium sativum L.), Indian J Exp Biol 34 (1996), pp. 634–640.
14. ^ Saulis, Alexandrina S. M.D.; Mogford, Jon H. Ph.D.; Mustoe, Thomas A. M.D. (2002). "Effect of Mederma on Hypertrophic Scarring in the Rabbit Ear Model". Plastic and Reconstructive Surgery 110 (1): 177–183. doi:10.1097/00006534-200207000-00029. PMID 12087249.
15. ^ "Onion Compound May Help Fight Osteoporosis" (html) (2005-04-11). Retrieved on 2008-01-30.
16. ^ Scott, Thomas. "What is the chemical process that causes my eyes to tear when I peel an onion?". Ask the Experts: Chemistry. Scientific American. Retrieved on 2007-04-28.
17. ^ Onions-USA.org FAQ
18. ^ news.com.au, Scientists create 'no tears' onions
19. ^ ^{a b} "Onion a day keeps doctor away?" (hmtl). Cornell University (2004-10-07). Retrieved on 2008-01-30.

References

• Sen, Colleen T. (2004). Food culture in India. Greenwood Publishing. ISBN 0313324875.

See also

• Barbagallo, Tricia (June 01, 2005). "Black Beach: The Mucklands of Canastota, New York". Retrieved on 2008-06-04.
• Onion Johnny
• A comic song has been recorded by UK comedy pop group The Badger Famine based entirely on this site's 'Historical Uses' paragraph. Lyrics can be found here: http://www.thebadgerfamine.co.uk/finestbulb.html
• Onions are also used in the popular game pikmin as a similar shaped object that can store pikmin and produce them.

External links

• PROTAbase on Allium cepa
• How to safely cut an onion (by Rachael Ray)
• The Secret to Cutting Onions Without Crying (by Steve Fry)
• Watch the Video: No Cry Onion Chopping (with Jonathon Stewart)
• Medicinal Pungent Onions

• All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.)
  Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity.
  

Broccoli

From Wikipedia, the free encyclopedia

Broccoli
Broccoli, cultivar unknown
Species
Brassica oleracea
Cultivar group
Italica Group
Origin
possibly Ancient Rome
Cultivar group members
Many; see text.

Broccoli is a plant of the Cabbage family, Brassicaceae (formerly Cruciferae). It is classified as the Italica Cultivar Group of the species Brassica oleracea. Broccoli possesses abundant fleshy flower heads, usually green in color, arranged in a tree-like fashion on branches sprouting from a thick, edible stalk. The large mass of flower heads is surrounded by leaves. Broccoli most closely resembles cauliflower, which is a different cultivar group of the same species, but broccoli is green rather than white. In the United States, the term refers exclusively to the form with a single large head. This form is sometimes called "Calabrese" in the United Kingdom, where sprouting (non-heading) types and those with underdeveloped flower buds are also sold as broccoli.

History

Test-plot-grown broccoli near Salinas, California, USA.

Cauliflower and broccoli output in 2005. Click the image for the details.

The word broccoli comes from the Italian broccolo, the diminuitive of brocco, meaning shoot, stalk. Broccoli is a cultivar of wild cabbage, remaining exactly the same species. Wild cabbage originated along the northern and western coasts of the Mediterranean, where it was apparently domesticated thousands of years ago.^[1][2] That domesticated cabbage was eventually bred into widely varying forms, including broccoli, cauliflower, cabbage, kale, kohlrabi, and brussels sprouts, all of which remain the same species. It is also assumed that broccoli is related to the Dandelion plant.^[3]

Roman references to a cabbage-family vegetable that may have been broccoli are less than perfectly clear: the Roman natural history writer, Pliny the Elder, wrote about a vegetable that fit the description of broccoli. This would imply that the Romans grew their own broccoli for culinary uses during the 1st century. Some vegetable scholars recognize broccoli in the cookbook of Apicius.

Broccoli was an Italian vegetable, as its name suggests, long before it was eaten elsewhere. At that time it was a sprouting type, not the single large head that is seen today. It is first mentioned in France in 1560, but in 1724 broccoli was still so unfamiliar in England that Philip Miller's Gardener's Dictionary (1724 edition) referred to it as a stranger in England and explained it as "sprout colli-flower" or "Italian asparagus." In the American colonies, Thomas Jefferson was also an experimenting gardener with a wide circle of European correspondents, from whom he got packets of seeds for rare vegetables. He noted the planting of broccoli at Monticello along with radishes, lettuce, and cauliflower on May 27, 1767. Nevertheless, broccoli remained exotic in American gardens. In 1775, John Randolph, in A Treatise on Gardening by a Citizen of Virginia, felt he had to explain about broccoli: "The stems will eat like Asparagus, and the heads like cauliflower."

Italians brought broccoli to North America by 1806^[4], but it did not become popular until the 1920s. Commercial cultivation of broccoli in the United States can be traced to the D'Arrigo brothers, Stephano and Andrea, Italian immigrants from Messina, whose company made some tentative plantings in San Jose, California, in 1922. A few crates were initially shipped to Boston, where there was a thriving Italian immigrant culture in the North End. The broccoli business boomed, with the D'Arrigo's brand name "Andy Boy" named after Stephano's two-year-old son, Andrew, and backed with advertisements on the radio.

Varieties

Purple cauliflower, a member of the Italica cultivar group.

There are three commonly grown types of broccoli. The most familiar is sometimes called Calabrese in Great Britain and simply 'broccoli' in North America. It has large (10 - 20 cm) green heads and thick stalks, and is named after Calabria in Italy where it was first cultivated. It is a cool season annual crop.

Sprouting broccoli has a larger number of heads with many thin stalks. It is planted in May to be harvested during the winter or early the following year in temperate climates.

Romanesco broccoli has a distinctive fractal appearance of its heads, and is yellow-green in colour. It is technically in the Botrytis (cauliflower) cultivar group

Purple cauliflower is a type of broccoli sold in southern Italy, Spain and the United Kingdom. It has a head shaped like cauliflower, but consisting of tiny flower buds. It sometimes, but not always, has a purple cast to the tips of the flower buds.

Cultivation, nutritional value, and preparation

Broccoli, raw (edible parts), 100g Nutritional value per 100 g (3.5 oz)
Energy 30 kcal 140 kJ
Carbohydrates 6.64 g - Sugars 1.7 g - Dietary fiber 2.6 g Fat 0.37 g Protein 2.82 g Water 89.30g Vitamin A equiv. 31 μg 3% - β-carotene 361 μg 3% Thiamin (Vit. B1) 0.071 mg 5% Riboflavin (Vit. B2) 0.117 mg 8% Niacin (Vit. B3) 0.639 mg 4% Pantothenic acid (B5) 0.573 mg 11% Vitamin B6 0.175 mg 13% Folate (Vit. B9) 63 μg 16% Vitamin C 89.2 mg 149% Calcium 47 mg 5% Iron 0.73 mg 6% Magnesium 21 mg 6% Phosphorus 66 mg 9% Potassium 316 mg 7% Zinc 0.41 mg 4%
Percentages are relative to US recommendations for adults. Source: USDA Nutrient database

Broccoli is a cool-weather crop that does poorly in hot summer weather. Broccoli grows best when exposed to an average daily temperature between 65 and 75 degrees Fahrenheit(18-23 degrees Celsius).^[5] The majority (99%) of the United States broccoli crop is grown in California and Arizona.^[6] Other cultivar groups of Brassica oleracea include: cabbage (Capitata Group), cauliflower (Botrytis Group), kale and collard greens (Acephala Group), kohlrabi (Gongylodes Group), and Brussels sprouts (Gemmifera Group). Chinese broccoli (Alboglabra Group) is also a cultivar group of Brassica oleracea.

Broccoli is high in vitamin C and soluble fiber and contains multiple nutrients with potent anti-cancer properties including diindolylmethane and selenium. The 3,3'-Diindolylmethane found in broccoli is a potent modulator of the innate immune response system with anti-viral, anti-bacterial and anti-cancer activity.^{[7] [8]} Broccoli also contains the compound glucoraphanin, which can be processed into an anticancer compound sulforaphane, though the benefits of broccoli are greatly reduced if the vegetable is boiled more than ten minutes.^[9] A high intake of broccoli has been found to reduce the risk of aggressive prostate cancer.^[10] Broccoli leaf is also edible and contains far more betacarotene than the florets.

Broccoli is usually boiled or steamed, but may be eaten raw and has become popular as a raw vegetable in hors-d'oeuvre trays. Although boiling has been shown to reduce the levels of suspected anticancer compounds in broccoli, other preparation methods such as steaming, microwaving, and stir-frying have been shown not to reduce the presence of these compounds.^[9]

Gallery

Extreme close-up of broccoli florets.	Broccoli flowers.	Two broccoli heads.	Romanesco broccoli, showing fractal forms
Steamed broccoli	Sicilian Purple Broccoli	Broccoli in flower

References

1. ^ Gray, A.R. (1982). "Taxonomy and evolution of broccoli ('Brassica oleracea' L. var. 'italica')". Economic Botany 36: 397–410.
2. ^ Boswell, V.R. (1949). "Our vegetable travelers". National Geographic Magazine 96: 145–217.
3. ^ Gray, A.R. (1982). "Taxonomy and evolution of broccoli ('Brassica oleracea' L. var. 'italica')". Economic Botany 36: 397–410.
4. ^ History of Broccoli and Cauliflower at YourHub.com
5. ^ "Broccoli Cultivation Factsheet, Clemson University extension (2003)". Retrieved on 2008-05-13.
6. ^ "Commodity Profile: Broccoli, University of California (2005)". Retrieved on 2008-05-13.
7. ^ "Diindolylmethane Information Resource Center at the University of California, Berkeley". Retrieved on 2007-06-10.
8. ^ "Diindolylmethane Immune Activation Data Center". Retrieved on 2007-06-10.
9. ^ ^{a b} Warwick Medical School, University of Warwick (2007-05-15). "Research Says Boiling Broccoli Ruins Its Anti Cancer Properties".
10. ^ Kirsh, VA; Peters U, Mayne ST, Subar AF, Chatterjee N, Johnson CC, Hayes RB (2007). "Prospective study of fruit and vegetable intake and risk of prostate cancer". Journal of the National Cancer Institute 99 (15): 1200–9. doi:10.1093/jnci/djm065. PMID 17652276. (News article)

External links

Wikimedia Commons has media related to:

Broccoli

• WHFoods.com: Broccoli
• PROTAbase on Brassica oleracea (cauliflower and broccoli)

• All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.)
  Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity.

Lettuce

From Wikipedia, the free encyclopedia

Lettuce Iceberg lettuce field in Northern Santa Barbara County Scientific classification Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Asterales Family: Asteraceae Genus: Lactuca Species: L. sativa Binomial name Lactuca sativa L.

Lettuce and chicory output in 2005

Lettuce (butterhead) Nutritional value per 100 g (3.5 oz) Energy 10 kcal 60 kJ Carbohydrates 2.2 g - Dietary fibre 1.1 g Fat 0.2 g Protein 1.4 g Water 96 g Vitamin A equiv. 166 μg 18% Folate (Vit. B9) 73 μg 18% Vitamin C 4 mg 7% Vitamin K 24 μg 23% Iron 1.2 mg 10% Vit. K[1] Percentages are relative to US recommendations for adults. Source: USDA Nutrient database

The Lettuce (Lactuca sativa) is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold and raw, in salads, hamburgers, tacos, and many other dishes. In some places, including China, lettuce is typically eaten cooked and use of the stem is as important as use of the leaf. Both the English name and the Latin name of the genus are ultimately derived from lac, the Latin word for “milk”,^[2] referring to the plant’s milky juice. Mild in flavour, it has been described over the centuries as a cooling counterbalance to other ingredients in a salad.^[3] In his humorous essay 100 Things I Hate, filmmaker John Waters refers to iceberg lettuce as "the polyester of greens".^[4]

Description

The lettuce plant has a short stem initially (a rosette growth habit), but when it blooms the stem lengthens and branches, and it produces many flower heads that look like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is harvested before it bolts. Lettuce is used as a food plant by the larvae of some Lepidoptera. The largest lettuce head, of the Salad Bowl cultivar, weighed 11 kg (25 lb) grown by Colin Bowcock of Willaston, England, in 1974.

Cultivation

Lettuce is grown commercially worldwide.

History

The lettuce that we see today actually started out as a weed around the Mediterranean basin. Served in dishes for over 4500 years, lettuce has certainly made its mark in history- as seen from tomb paintings in Egypt to the depiction of many different varieties in ancient Greek relics. Christopher Columbus introduced lettuce to the new world.^[5]

Cultivars

There are six commonly recognised Cultivar Groups of lettuce which are ordered here by head formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf shape and colour, as well as extended field and shelf life, within each of these Cultivar Groups:

• Butterhead, also called Boston or Bibb, forms loose heads; it has a buttery texture. Butterhead cultivars are most popular in Europe.
• Chinese lettuce types generally have long, sword-shaped, non-head-forming leaves, with a bitter and robust flavour unlike Western types, appropriate for use in stir-fried dishes and stews. Chinese lettuce cultivars are divided into “stem-use” types (called celtuce in English), and “leaf-use” types such as youmaicai (Chinese: 油麦菜; pinyin: yóumàicài) or shengcai (生菜).
• Crisphead, also called Iceberg, which form tight, dense heads that resemble cabbage. They are generally the mildest of the lettuces, valued more for their crunchy texture than for flavour. Cultivars of iceberg lettuce are the most familiar lettuces in the USA. The name Iceberg comes from the way the lettuce was transported in the US starting in the 1920s on train-wagons covered in crushed ice, making them look like icebergs.
• Looseleaf, with tender, delicate, and mildly flavoured leaves. This group comprises oak leaf and lollo rosso lettuces.
• Romaine, also called Cos, grows in a long head of sturdy leaves with a firm rib down the center. Unlike most lettuces, it is tolerant of heat.
• Summer Crisp, also called Batavian, which form moderately dense heads with a crunchy texture; this type is intermediate between iceberg and looseleaf types.

Some lettuces (especially iceberg) have been specifically bred to remove the bitterness from their leaves. These lettuces have a high water content with very little nutrient value. The more bitter lettuces and the ones with pigmented leaves contain antioxidants.

Some lettuce cultivars

A Romaine lettuce

Chemical compunds which occur in lettuce: 1: α-Lactucerol (=Taraxasterol); 2: β-Lactucerol (=Lactucon, Lactucerin); 3: Lactucin; 4: Lactucopicrin.

More lettuce cultivars

Breeding

L. sativa can easily be bred with closely related species in Lactuca such as L. serriola, L. saligna, and L. virosa, and breeding programs for cultivated lettuce have included those species to broaden the available gene pool. Starting in the 1990s, breeding programs began to include more distantly related species such as L. tatarica.^[6]

Nutrition

Lettuce is a fat free, low calorie food. It is a valuable source of vitamin A and folic acid. Lactucarium (or “Lettuce Opium”) is a mild opiate-like substance that is contained in all types of lettuce. Both the Romans and Egyptians took advantage of this property eating lettuce at the end of a meal to induce sleep.^[7]

Religious restrictions

The Yazidi of northern Iraq consider eating lettuce taboo.

Notes

1. ^ Molly Damon, Nancy Z. Zhang, David B. Haytowitz, Sarah L. Booth (2005). "Phylloquinone (vitamin K₁) content of vegetables". Journal of Food Composition and Analysis 18: 751–758. Elsevier. doi:10.1016/j.jfca.2004.07.004.
2. ^ Simpson, D.P. (1979). Cassell's Latin Dictionary, 5, London: Cassell Ltd., 883. ISBN 0-304-52257-0.
3. ^ Grigson, Jane (1978). The Vegetable Book. London: Penguin, p. 312-14. ISBN 0-14-046-352-6.
4. ^ Waters, John (1987). Crackpot: the Obsessions of John Waters. Vintage. ISBN 0394755340.
5. ^ "Lettuce:Food Facts & Trivia". Retrieved on 2007-11-02.
6. ^ Wim J. M. Koopman, Eli Guetta, Clemens C. M. van de Wiel, Ben Vosman and Ronald G. van den Berg (1998). "Phylogenetic relationships among Lactuca (Asteraceae) species and related genera based on ITS-1 DNA sequences" 1517–1530.
7. ^ "Lettuce - Lactuca sativa - Daisy family". Hamilton, Dave (2005).

References

Wikibooks has a book on the topic of

Gardening/Lettuce

• "Iceberg and Leaf Lettuce", University of California

• All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.)
  Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity.