Pea

Pea
Peas are contained within a pod
Pea plant: Pisum sativum
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Vicieae
Genus: Pisum
Species: P. sativum
Binomial name
Pisum sativum
L.

A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum.[1] Each pod contains several peas. Peapods are botanically a fruit,[2] since they contain seeds developed from the ovary of a (pea) flower. However, peas are considered to be a vegetable in cooking. The name is also used to describe other edible seeds from the Fabaceae such as the pigeon pea (Cajanus cajan), the cowpea (Vigna unguiculata), and the seeds from several species of Lathyrus.

P. sativum is an annual plant, with a life cycle of one year. It is a cool season crop grown in many parts of the world; planting can take place from winter to early summer depending on location. The average pea weighs between 0.1 and 0.36 grams.[3] The species is used as a vegetable, fresh, frozen or canned, and is also grown to produce dry peas like the split pea. These varieties are typically called field peas.

The wild pea is restricted to the Mediterranean basin and the Near East. The earliest archaeological finds of peas come from Neolithic Syria, Turkey and Jordan. In Egypt, early finds date from ca. 4800–4400 BC in the Nile delta area, and from ca. 3800–3600 BC in Upper Egypt. The pea was also present in Georgia in the 5th millennium BC. Farther east, the finds are younger. Peas were present in Afghanistan ca. 2000 BC, in Harappa, Pakistan, and in northwest India in 2250–1750 BC. In the second half of the 2nd millennium BC, this pulse crop appears in the Gangetic basin and southern India.[4]

Contents

Description

The pea is a most commonly green, occasionally purple[5] or golden yellow,[6] pod-shaped vegetable, widely grown as a cool season vegetable crop. The seeds may be planted as soon as the soil temperature reaches 10 °C (50 °F), with the plants growing best at temperatures of 13 to 18 °C (55 to 64 °F). They do not thrive in the summer heat of warmer temperate and lowland tropical climates, but do grow well in cooler, high altitude, tropical areas. Many cultivars reach maturity about 60 days after planting.

Raw Green Pea
Nutritional value per 100 g (3.5 oz)
Energy 339 kJ (81 kcal)
Carbohydrates 14.5 g
- Sugars 5.7 g
- Dietary fibre 5.1 g
Fat 0.4 g
Protein 5.4 g
Vitamin A equiv. 38 μg (5%)
- beta-carotene 449 μg (4%)
- lutein and zeaxanthin 2593 μg
Thiamine (vit. B1) 0.3 mg (26%)
Riboflavin (vit. B2) 0.1 mg (8%)
Niacin (vit. B3) 2.1 mg (14%)
Pantothenic acid (B5) 0.1 mg (2%)
Vitamin B6 0.2 mg (15%)
Folate (vit. B9) 65 μg (16%)
Vitamin C 40.0 mg (48%)
Calcium 25.0 mg (3%)
Iron 1.5 mg (12%)
Magnesium 33.0 mg (9%)
Phosphorus 108 mg (15%)
Potassium 244 mg (5%)
Zinc 1.2 mg (13%)
Percentages are relative to US recommendations for adults.
Source: USDA Nutrient Database

Peas have both low-growing and vining cultivars. The vining cultivars grow thin tendrils from leaves that coil around any available support and can climb to be 1–2 m high. A traditional approach to supporting climbing peas is to thrust branches pruned from trees or other woody plants upright into the soil, providing a lattice for the peas to climb. Branches used in this fashion are sometimes called pea brush. Metal fences, twine, or netting supported by a frame are used for the same purpose. In dense plantings, peas give each other some measure of mutual support. Pea plants can self-pollinate.[7]

Varieties

There are many varieties (cultivars) of garden peas. Some of the most common include:

Other variations of P. sativum include:

Both of these are eaten whole before the pod reaches maturity and are hence also known as mange-tout, French for "eat all". The snow pea pod is eaten flat, while in sugar/snap peas, the pod becomes cylindrical, but is eaten while still crisp, before the seeds inside develop.

Pests and diseases

The pea leaf weevil (Sitona lineatus) is an insect that damages peas and other pod fruits. It is native to Europe, but has spread to other places such as Alberta, Canada. They are about 3.5 millimetres (0.14 in)—5.5 millimetres (0.22 in) long and are distinguishable by three light-coloured stripes running length-wise down the thorax. The weevil larvae feed on the root nodules of pea plants, which are essential to the plants' supply of nitrogen, and thus diminish leaf and stem growth. Adult weevils feed on the leaves and create a notched, "c-shaped" appearance on the outside of the leaves.[10]

Use

Culinary use

In early times, peas were grown mostly for their dry seeds. In modern times, however, peas are usually boiled or steamed, which breaks down the cell walls and makes the taste sweeter and the nutrients more bioavailable. Along with broad beans and lentils, these formed an important part of the diet of most people in the Middle East, North Africa and Europe during the Middle Ages.[11] By the 17th and 18th centuries, it had become popular to eat peas "green", that is, while they are immature and right after they are picked. This was especially true in France and England, where the eating of green peas was said to be "both a fashion and a madness".[12] New cultivars of peas were developed by the English during this time, which became known as "garden" or "English" peas. The popularity of green peas spread to North America. Thomas Jefferson grew more than 30 cultivars of peas on his estate.[13] With the invention of canning and freezing of foods, green peas became available year-round, and not just in the spring as before.

Fresh peas are often eaten boiled and flavored with butter and/or spearmint as a side dish vegetable. Salt and pepper are also commonly added to peas when served. Fresh peas are also used in pot pies, salads and casseroles. Pod peas (particularly sweet cultivars called mange tout and "sugar peas", or the flatter "snow peas," called hé lán dòu, 荷兰豆 in Chinese) are used in stir-fried dishes, particularly those in American Chinese cuisine.[14] Pea pods do not keep well once picked, and if not used quickly, are best preserved by drying, canning or freezing within a few hours of harvest.

In India, fresh peas are used in various dishes such as aloo matar (curried potatoes with peas) or matar paneer (paneer cheese with peas), though they can be substituted with frozen peas as well. Peas are also eaten raw, as they are sweet when fresh off the bush. Split peas are also used to make dhal, particularly in Guyana, and Trinidad, where there is a significant population of Indians.

Dried peas are often made into a soup or simply eaten on their own. In Japan, China, Taiwan and some Southeast Asian countries, including Thailand and Malaysia, peas are roasted and salted, and eaten as snacks. In the UK, dried yellow split peas are used to make pease pudding (or "pease porridge"), a traditional dish. In North America, a similarly traditional dish is split pea soup.

Pea soup is eaten in many other parts of the world, including northern Europe, parts of middle Europe, Russia, Iran, Iraq and India.[15] In Sweden it is called ärtsoppa, and is eaten as a traditional Swedish food which predates the Viking era. This food was made from a fast-growing pea that would mature in a short growing season. Ärtsoppa was especially popular among the many poor who traditionally only had one pot and everything was cooked together for a dinner using a tripod to hold the pot over the fire.

In Chinese cuisine, pea sprouts (豆苗; dòu miáo) are commonly used in stir-fries. Pea leaves are often considered a delicacy, as well.

In Greece, Turkey, Cyprus, and other parts of the Mediterranean, peas are made into a stew with meat and potatoes.

In Hungary and Serbia, pea soup is often served with dumplings and spiced with hot paprika.

In the United Kingdom, dried, rehydrated and mashed marrowfat peas, known by the public as mushy peas, are popular, originally in the north of England, but now ubiquitously, and especially as an accompaniment to fish and chips or meat pies, particularly in fish and chip shops. Sodium bicarbonate is sometimes added to soften the peas. In 2005, a poll of 2,000 people revealed the pea to be Britain's seventh favourite culinary vegetable.[16]

Processed peas are mature peas which have been dried, soaked and then heat treated (processed) to prevent spoilage—in the same manner as pasteurising. Cooked peas are sometimes sold dried and coated with wasabi, salt, or other spices.

Bioplastics

Bioplastics can be made using pea starch.

Nutritional value

Peas are high in fiber, protein, vitamins, minerals, and lutein. Dry weight is about one-quarter protein and one-quarter sugar.[17] Pea seed peptide fractions have less ability to scavenge free radicals than glutathione, but greater ability to chelate metals and inhibit linoleic acid oxidation.[18]

1cup of raw green peas (145g) contains:

Peas in science

In the mid-19th century, Austrian scientist Gregor Mendel's observations of pea pods led to the principles of Mendelian genetics, the foundation of modern genetics.[19]

Peas in medicine

Some people are allergic to peas, as well as lentils.[20]

Etymology

According to etymologists, the term pea was taken from the Latin pisum, which is the latinisation of the Greek πίσον (pison), neut. of πίσος (pisos), "pea".[21][22] It was adopted into English as the noun pease (plural peasen), as in pease pudding. However, by analogy with other plurals ending in -s, speakers began construing pease as a plural and constructing the singular form by dropping the "s", giving the term "pea". This process is known as back-formation.

The name "marrowfat pea" for mature dried peas is recorded by the Oxford English Dictionary as early as 1733. The fact that an export cultivar popular in Japan is called Maro has led some people to assume mistakenly that the English name "marrowfat" is derived from Japanese.

See also

Notes

  1. ^ Oxford English Dictionary - Pea
  2. ^ Rogers, Speed (2007). Man and the Biological World Read Books. pp. 169–170. ISBN 978-1-4067-3304-4 retrieved on 2009-04-15.
  3. ^ Pea
  4. ^ Zohary, Daniel and Hopf, Maria (2000). Domestication of Plants in the Old World, third edition. Oxford: University Press. ISBN 978-0-19-850356-9 p. 105–107
  5. ^ Purple podded peas
  6. ^ Pea Golden Podded, The Diggers Club
  7. ^ Alternative Field Crops Manual: Dry Field Pea
  8. ^ "Vegetable Cultivar Descriptions for North America". http://cuke.hort.ncsu.edu/cucurbit/wehner/vegcult/peagreenal.html. 
  9. ^ "Lincoln Peas". http://www.victoryseeds.com/pea_lincoln.html. 
  10. ^ Barkley, Shelley (2007-05-02). "Pea Leaf Weevil". Agriculture and Rural Development website. Government of Alberta. http://www1.agric.gov.ab.ca/$Department/deptdocs.nsf/all/prm11287. Retrieved 2009-04-05. 
  11. ^ Bianchini, F.; Corbetta, F. (1976), The Complete Book of Fruits and Vegetables, New York: Crown, p. 40, ISBN 978-0-517-52033-8 
  12. ^ Hedrick, U.P. (1919), "Sturtevant's Notes on Edible Plants", Report of the New York Agricultural Experiment Station for the Year 1919 II, Albany: J.B Lyon Company, State Printers, http://food.oregonstate.edu/glossary/p/pplant189.html, retrieved Feb. 26, 2010 
  13. ^ Kafka, B. (2005), Vegetable Love, New York: Artisan, p. 297, ISBN 978-1-57965-168-8 
  14. ^ Healthnotes | Snow Peas | Selecting & Varieties
  15. ^ "Sanningen om ärtsoppan" (Swedish)
  16. ^ Wainwright, Martin (2005-05-23). "Onions come top for British palates". The Guardian (London). http://www.guardian.co.uk/uk/2005/may/23/britishidentity.foodanddrink. 
  17. ^ Jegtvig, Shereen (July 17, 2007). "Peas". Nutrition. About.com. http://nutrition.about.com/od/fruitsandvegetables/p/peas.htm. Retrieved 2011-01-28. 
  18. ^ Pownall TL, Udenigwe CC, Aluko RE (2010). "Amino acid composition and antioxidant properties of pea seed ( Pisum sativum L.) enzymatic protein hydrolysate fractions". JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 58 (8): 4712–4718. doi:10.1021/jf904456r. PMID 20359226. 
  19. ^ Gregor Mendel: The Pea Plant Experiment
  20. ^ Sanchez-Monge, R.; G. Lopez-Torrejon, C. Y. Pascual, J. Varela, M. Martin-Esteban, G. Salcedo (2004). "Vicilin and convicilin are potential major allergens from pea". Clinical & Experimental Allergy 34 (11): 1747–1753. doi:10.1111/j.1365-2222.2004.02085.x. ISSN 0954-7894. 
  21. ^ Oxford English Dictionary
  22. ^ πίσος, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library

References

External links