Pea ( pisum in Latin) is a Legume, vegetable or fodder crop, but the word often refers to the seed or sometimes the pod of this flowering plant species. Carl Linnaeus gave the species the scientific name Pisum sativum in 1753 (meaning Sativum pea). Some sources now treat it as Lathyrus oleraceus;[Rogers, Speed (2007). Man and the Biological World Read Books. pp. 169–170. . Retrieved on 2009-04-15.] since they contain seeds and develop from the ovary of a (pea) flower. The name is also used to describe other edible seeds from the Fabaceae such as the pigeon pea ( Cajanus cajan), the cowpea ( Vigna unguiculata), the seeds from several species of Lathyrus and is used as a compound form for example Sturt's desert pea.
Peas are , with a life cycle of one year. They are 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 .
Description
A pea is a most commonly green, occasionally golden yellow,
Peas have both low-growing and vine cultivars. The vining cultivars grow thin from leaves that coil around any available support and can climb to be high. A traditional approach to supporting climbing peas is to thrust branches pruned from or other woody plants upright into the soil, providing a lattice for the peas to climb. Branches used in this fashion are called pea sticks
Genome
The pea karyotype consists of seven , five of which are acrocentric and two submetacentric.
Taxonomy
Carl Linnaeus gave the species the scientific name Pisum sativum in 1753 (meaning Sativum pea). Some sources now treat it as Lathyrus oleraceus,
Etymology
The term pea originates from the Latin word pisum,[.]
Varieties
Garden peas
There are many varieties () of garden peas. Some of the most common varieties are listed here. PMR indicates some degree of powdery mildew resistance; afila types, also called semi-leafless, have clusters of tendrils instead of leaves.
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Alaska, 55 days (smooth seeded)
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Tom Thumb / Half Pint, 55 days (Heirloom plant, extra dwarf)
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Thomas Laxton (heirloom) / Laxton's Progress / Progress #9, 60–65 days
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Mr. Big, 60 days, 2000 AAS winner
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Little Marvel, 63 days, 1934 AAS winner
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Early Perfection, 65 days
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Kelvedon Wonder, 65 days, 1997 RHS AGM winner
[Kelvedon Wonder is popular in the United Kingdom, but uncommon elsewhere.]
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Sabre, 65 days, PMR
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Homesteader / Lincoln, 67 days (heirloom, known as Greenfeast in Australia and New Zealand)
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Miragreen, 68 days (tall climber)
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Serge, 68 days, PMR, afila
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Wando, 68 days
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Green Arrow, 70 days
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Recruit, 70 days, PMR, afila
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Tall Telephone / Alderman, 75 days (heirloom, tall climber)
Edible-pod peas
Some peas lack the tough membrane inside the pod wall and have tender edible pods.
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have flat pods with thin pod walls. Pods and seeds are eaten when they are very young.
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or sugar snap peas have rounded pods with thick pod walls. Pods and seeds are eaten before maturity.
The name sugar pea can include both types
Snow peas and snap peas both belong to Macrocarpon Group,
The scientific name Pisum sativum var. saccharatum Ser. is often misused for snow peas. The variety under this name was described as having sub-leathery and compressed-terete pods and a French name of petit pois.
Field peas
The field pea is a type of pea sometimes called P. sativum subsp. arvense (L.) Asch. It is also known as dun (grey-brown) pea, Kapucijner pea, or Austrian winter pea, and is one of the oldest domesticated crops, cultivated for at least 7,000 years. Field peas are now grown in many countries for both human consumption and stockfeed. There are several cultivars and colors including blue, dun (brown), maple and white. This pea should not be confused with the cowpea ( Vigna unguiculata) which is sometimes called the "field pea" in warmer climates.
It is a climbing annual legume with weak, viny, and relatively succulent stems. Vines often are 4 to 5 feet (120 to 150 cm) long, but when grown alone, field pea's weak stems prevent it from growing more than 1.5 to 2 feet (45 to 60 cm) tall. Leaves have two leaflets and a tendril. Flowers are white, pink, or purple. Pods carry seeds that are large (4,000 seeds/lb), nearly spherical, and white, gray, green, or brown. The root system is relatively shallow and small, but well nodulated.
The field pea is a cool-season legume crop that is grown on over 25 million acres worldwide. It has been an important grain legume crop for millennia, seeds showing domesticated characteristics dating from at least 7,000 years ago have been found in archaeological sites around what is now Turkey. Field peas or "dry peas" are marketed as a dry, shelled product for either human or livestock food, unlike the garden pea, which is marketed as a fresh or canned vegetable. The major producing countries of field peas are Russia and China, followed by Canada, Europe, Australia and the United States. Europe, Australia, Canada and the U.S. raise over 4.5 million acres (18,000 km²) and are major exporters of peas. In 2002, there were approximately 300,000 acres (1,200 km²) of field peas grown in the U.S.
Distribution and habitat
The wild pea is restricted to the Mediterranean Basin and the Near East. The earliest archaeological finds of peas date from the late Neolithic era of current Syria, Anatolia, Israel, Iraq, Jordan and Greece. In Egypt, early finds date from –4400 BC in the Nile delta area, and from c. 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 c. 2000 BC, in Harappan civilization around modern-day Pakistan and western- and northwestern India in 2250–1750 BC. In the second half of the 2nd millennium BC, this legume crop appears in the Ganges Basin and southern India.[Zohary, Daniel and Hopf, Maria (2000). Domestication of Plants in the Old World, third edition. Oxford: University Press. . pp. 105–107.]
Cultivation
History
In early times, peas were grown mostly for their dry seeds.[Maguelonne Toussaint-Samat, A History of Food, 2nd ed. 2009:38ff.] From plants growing wild in the Mediterranean Basin, constant selection since the Neolithic dawn of agriculture[Peas have been found in the Neolithic site of Abeurador in the south of France (Toussaint-Samat).] improved their yield.
Peas are mentioned in Aristophanes' The Birds The Greeks and Romans were cultivating this legume from around 500 BC to 400 BC, with vendors in the streets of Athens selling hot pea soup.[: "vendors in the streets of classical Athens were selling hot pea soup."]
In the early 3rd century BC, Theophrastus mentions peas among the legumes that are sown late in the winter because of their tenderness.[Theophrastus, Historia Plantarum, VIII.i.4.]
In the first and second centuries BC, Cato the Elder and Varro both mention peas in their respective works De agri cultura and De re rustica.[Hooper, William Davis & Ash, Harrison Boyd: Marcus Porcius Cato, On agriculture; Marcus Terentius Varro, On agriculture Volume 283 of Loeb classical library. Loeb classical library. Latin authors. Harvard University Press, 1934. Pages 141, 257, 299, 465.]
In the Middle Ages, field peas are constantly mentioned, as they were the staple that kept famine at bay, as Charles the Good, count of Flanders, noted explicitly in 1124.[Edict quoted in Michel Pitrat and Claude Four, Histoires de légumes: Des origines à l'orée du XXIe siècle, "Le pois au cours des siècles" :353.]
Green "garden" peas, eaten immature and fresh, were an innovative luxury of Early Modern Europe. In England, the distinction between field peas and garden peas dates from the early 17th century: John Gerard and John Parkinson both mention garden peas. Snow and snap peas, which the French called mange-tout, because they were eaten pods and all, were introduced to France from the market gardens of Holland in the time of Henri IV, through the French ambassador. Green peas were introduced from Genoa to the court of Louis XIV of France in January 1660, with some staged fanfare. A hamper of them was presented before the King. They were shelled by the Savoyan comte de Soissons, who had married a niece of Cardinal Mazarin. Little dishes of peas were then presented to the King, the Queen, Cardinal Mazarin and Monsieur, the king's brother.[An account is in Toussaint-Samat.] Immediately established and grown for earliness warmed with manure and protected Greenhouse, they were still a luxurious delicacy in 1696, when Mme de Maintenon and Mme de Sevigné each reported that they were "a fashion, a fury".[Quoted by Michel Pitrat and Claude Four.]
The first sweet tasting pea was developed in the 18th century by amateur plant breeder Thomas Edward Knight of Downton, near Salisbury, England.
The top producer of green peas is China with 12.2 million tons, followed by India (4.8 million tons), the U.S. (0.31 million tons), France (0.23 million tons) and Egypt (0.15 million tons). The United Kingdom, Pakistan, Algeria, Peru and Turkey complete the top 10.
Grading
Pea grading involves sorting peas by size, in which the smallest peas are graded as the highest quality for their tenderness.[Sivasankar, B. (2002). Food Processing and Preservation. PHI Learning Pvt. Ltd. pp. 175–177. ] Brines may be used, in which peas are floated, from which their density can be determined.
Pests and diseases
A variety of diseases affect peas through a number of , including insects, viruses, bacteria and fungi.
Additionally, insects such as the pea leaf weevil ( Sitona lineatus) can damage peas and other pod fruits. The pea leaf weevil is native to Europe, but has spread to other places such as Alberta, Canada. They are about — long and are distinguishable by three light-coloured stripes running length-wise down the thorax. The weevil feed on the 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.
The Cydia nigricana can be a serious pest producing caterpillars the resemble small white maggots in the pea-pods. The caterpillars eat the developing peas making them unsightly and unsuitable for culinary use.
Potential adverse effects
Some people experience allergic reactions to peas, as well as , with vicilin or convicilin as the most common allergens.
Favism, or Fava-bean-ism, is a Genetic disorder of the enzyme glucose-6-phosphate dehydrogenase that affects Jews, other Middle Eastern Semitic peoples, and other descendants of the Mediterranean coastal regions. In this condition, the toxic reaction to eating most, if not all, is hemolytic anemia, and in severe cases, the released circulating free hemoglobin causes acute kidney injury.
Uses
Nutrition
Raw green peas are 79% water, 14% , 5% protein, and contain negligible fat. In a reference amount of , raw green peas supply of food energy, and are a rich source (20% or more of the Daily Value, DV) of vitamin C (48% DV), vitamin K, thiamine, and manganese, with several B vitamins and in moderate amounts (11–16% DV).
Culinary
In modern times peas are usually boiled or steamed, which breaks down the cell walls and makes them taste sweeter and the nutrients more Bioavailability. Along with and , these formed an important part of the diet of most people in the Middle East, North Africa and Europe during the Middle Ages.
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 , salads and . Pod peas ( and ) are used in stir-fried dishes, particularly those in American Chinese cuisine.
Dried peas are often made into a soup or simply eaten on their own. In Japan, China, Taiwan and some countries, including Thailand, the Philippines and Malaysia, peas are roasted and salted, and eaten as . In the Philippines, peas, while still in their pods, are a common ingredient in viands and pansit. In the UK, dried yellow or green 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.
In India, fresh peas are used in various dishes such as aloo matar (curried potatoes with peas) or mattar 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. Green peas known as hasiru batani in Kannada are used to make curry and gasi.
In Chinese cuisine, the tender new growth leaves dou miao (豆苗; dòu miáo) are commonly used in stir-fries. Much like picking the leaves for tea, the farmers pick the tips off of the pea plant.
In Greece, Tunisia, Turkey, Cyprus, and other parts of the Mediterranean, peas are made into a stew with lamb and potatoes.
In Hungary and Serbia, pea soup is often served with and spiced with hot paprika.
In the United Kingdom, dried, rehydrated and mashed marrowfat peas, or cooked green split peas, known as mushy peas, are popular, originally in the north of England, but now ubiquitously, and especially as an accompaniment to fish and chips or , 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.
Processed peas are mature peas which have been dried, soaked and then heat treated (processed) to prevent spoilage—in the same manner as Pasteurization. Cooked peas are sometimes sold dried and coated with wasabi, salt, or other spices.
In North America pea milk is produced and sold as an alternative to cow milk for a variety of reasons.
File:Wasabi peas - Massachusetts.jpg|Wasabi peas
File:Fish and chips at Sainsbury's Low Hall, Chingford, London.jpg|Fish and chips with peas
File:Pea soup 2.jpg|Pea soup
File:Aloo Matar.JPG|Aloo mutter
File:Matar Panir mit Chapati - Mutter Paneer with chapati.jpg|Matar paneer with chapati
Pea sprouts
In East Asia, pea sprouts or shoots (豆苗; 완두순)
Manufacturing
Frozen peas
In order to freeze and preserve peas, they must first be grown, picked, and shelled. Usually, the more tender the peas are, the more likely that they will be used in the final product. The peas must be put through the process of freezing shortly after being picked so that they do not spoil too soon. Once the peas have been selected, they are placed in ice water and allowed to cool. After, they are sprayed with water to remove any residual dirt or dust that may remain on them. The next step is blanching. The peas are boiled for a few minutes to remove any enzymes that may shorten their shelf life. They are then cooled and removed from the water. The final step is the actual freezing to produce the final product.
Science
In the mid-19th century, Austrian monk Gregor Mendel's observations of pea pods led to the principles of Mendelian genetics, the foundation of modern genetics.
Mendel chose peas for his experiments because he could grow them easily, pure-bred strains were readily available,
Mendel reasoned that each parent had a 'vote' in the appearance of the offspring, and the non-dominant, or recessive, trait appeared only when it was inherited from both parents. He did further experiments that showed each trait is separately inherited. Unwittingly, Mendel had solved a major problem with Charles Darwin's theory of evolution: how new traits were preserved and not blended back into the population, a question Darwin himself did not answer. Mendel's work was published in an obscure Austrian journal and was not rediscovered until about 1900.
Nitrogen fixation
Peas, like many legumes, contain symbiosis bacteria called Rhizobia within of their root. These bacteria have the special ability to fix nitrogen from atmospheric, molecular nitrogen () into ammonia ().
Ammonia is then converted to another form, ammonium (), usable by (some) plants by the following reaction:
The root nodules of peas and other legumes are sources of nitrogen that they can use to make , constituents of proteins. Hence, legumes are good sources of plant protein.
When a pea plant dies in the field, for example following the harvest, all of its remaining nitrogen, incorporated into inside the remaining plant parts, is released back into the soil. In the soil, the amino acids are converted to nitrate (), that is available to other plants, thereby serving as fertilizer for future crops.[Postgate, J (1998). Nitrogen Fixation, 3rd Edition. Cambridge University Press, Cambridge UK]
See also
Bibliography
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European Association for Grain Legume Research (AEP). Pea
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Hernández Bermejo, J. E. & León, J., (1992). Neglected crops: 1492 from a different perspective, Food and Agricultural Organization of the United Nations (FAO) Contents
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Muehlbauer, F. J. and Tullu, A., (1997). Pisum sativum L. Purdue University. Pea
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Oelke, E. A., Oplinger E. S., et al. (1991). Dry Field Pea. University of Wisconsin. Dry Field Pea
External links
