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| Peanut |
The peanut, or groundnut (Arachis hypogaea), is a species in the legume or "bean" family (Fabaceae). The cultivated peanut was probably first domesticated in the valleys of Peru. It is an annual herbaceous plant growing 30 to 50 cm (0.98 to 1.6 ft) tall. The leaves are opposite, pinnate with four leaflets (two opposite pairs; no terminal leaflet), each leaflet 1 to 7 cm (⅜ to 2¾ in) long and 1 to 3 cm (⅜ to 1 inch) broad. The flowers are a typical peaflower in shape, 2 to 4 cm (¾ to 1½ in) across, yellow with reddish veining. After pollination, the fruit develops into a legume 3 to 7 cm (1.2 to 2.8 in) long, containing 1 to 4 seeds, which forces its way underground to mature. Hypogaea means "under the earth."
Peanuts are known by many other local names such as earthnuts, ground nuts, goober peas, monkey nuts, pygmy nuts and pig nuts.
The domesticated peanut is an amphidiploid or allotetraploid, meaning that it has two sets of chromosomes from two different species, thought to be A. duranensis and A. ipaensis. These likely combined in the wild to form the tetraploid species A. monticola, which gave rise to the domesticated peanut. This domestication might have taken place in Paraguay or Bolivia, where the wildest strains grow today. Many pre-Columbian cultures, such as the Moche, depicted peanuts in their art.
Archeologists have (thus far) dated the oldest specimens to about 7,600 years found in Peru. Cultivation spread as far as Mesoamerica where the Spanish conquistadors found the tlalcacahuatl (Nahuatl = 'peanut,' whence Mexican Spanish, cacahuate and French, cacahuète) being offered for sale in the marketplace of Tenochtitlan (Mexico City). The plant was later spread worldwide by European traders.
Cultivation
he orange veined, yellow petaled, pea-like flower of the Arachis hypogaea is borne in axillary clusters above ground. Following self-pollination, the flowers fade and wither. The stalk at the base of the ovary, called the pedicel, elongates rapidly, and turns downward to bury the fruits several inches in the ground, where they complete their development. The entire plant, including most of the roots, is removed from the soil during harvesting.
The pods act in nutrient absorption. The fruits have wrinkled shells that are constricted between pairs of the one to four (usually two) seeds per pod.
Peanuts grow best in light, sandy loam soil. They require five months of warm weather, and an annual rainfall of 500 to 1,000 mm (20 to 39 in) or the equivalent in irrigation water.
The pods ripen 120 to 150 days after the seeds are planted. If the crop is harvested too early, the pods will be unripe. If they are harvested late, the pods will snap off at the stalk, and will remain in the soil.
Peanuts are particularly susceptible to contamination during growth and storage. Poor storage of peanuts can lead to an infection by the mold fungus Aspergillus flavus, releasing the toxic and highly carcinogenic substance aflatoxin. The aflatoxin-producing molds exist throughout the peanut growing areas and may produce aflatoxin in peanuts when conditions are favorable to fungal growth.
Harvesting occurs in two stages. In mechanized systems a machine is used to cut off the main root of the peanut plant by cutting through the soil just below the level of the peanut pods. The machine lifts the "bush" from the ground and shakes it, then inverts the bush, leaving the plant upside down on the ground to keep the peanuts out of the dirt. This allows the peanuts to dry slowly to a bit less than a third of their original moisture level over a period of 3–4 days. Traditionally, peanuts are pulled and inverted by hand.
fter the peanuts have dried sufficiently, they are threshed, removing the peanut pods from the rest of the bush.
Cultivars
Thousands of peanut cultivars are grown, with four major cultivar groups being the most popular: Spanish, Runner, Virginia, and Valencia. There are also Tennessee red and white groups. Certain cultivar groups are preferred for particular uses because of differences in flavor, oil content, size, shape, and disease resistance. For many uses the different cultivars are interchangeable. Most peanuts marketed in the shell are of the Virginia type, along with some Valencias selected for large size and the attractive appearance of the shell. Spanish peanuts are used mostly for peanut candy, salted nuts, and peanut butter. Most Runners are used to make peanut butter.
The various types are distinguished by branching habit and branch length. There are numerous varieties of each type of peanut. There are two main growth forms, bunch and runner. Bunch types grow upright, while runner types grow near the ground.
Each year new cultivars of peanuts are bred and introduced. Introducing a new cultivar may mean change in the planting rate, adjusting the planter, harvester, dryer, cleaner, sheller, and method of marketing.
Varied applications
Peanuts have many uses. They can be eaten as straight food, used in recipes, made into solvents and oils, used in make-up, medicines, textile materials, peanut butter, as well as many other uses. Popular confections made from peanuts include salted peanuts, peanut butter (sandwiches, peanut candy bars, peanut butter cookies, and cups), peanut brittle, and shelled nuts (plain/roasted). Peanuts, served by themselves, are one of the most popular nuts in the world. They are often eaten as snacks, served at cocktail parties and are sometimes added as a balanced and nutritional side dish with lunch. Salted peanuts are usually roasted in oil and packed in retail-size plastic bags or hermetically sealed cans. Dry roasted, salted peanuts are also marketed in significant quantities. Peanuts are often a major ingredient in mixed nuts because of their inexpensiveness compared to Brazil nuts, cashews, walnuts, and so on. Although peanut butter has been a tradition on camping trips and the like because of its high protein count and the fact that it resists spoiling for long periods of time, the primary use of peanut butter is in the home, but large quantities are also used in the commercial manufacture of sandwiches, candy, and bakery products. Boiled peanuts are a preparation of raw, unshelled green peanuts boiled in brine and eaten as a snack in the United States. More recently, fried peanut recipes have emerged - allowing both shell and nut to be eaten. Peanuts are also used in a wide variety of other areas, such as cosmetics, nitroglycerin, plastics, dyes and paints.
Peanut oil
Peanut oil is often used in cooking, because it has a mild flavor and a relatively high smoke point. Due to its high monounsaturated content, it is considered more healthy than saturated oils, and is resistant to rancidity. There are several types of peanut oil including: aromatic roasted peanut oil, refined peanut oil, extra virgin or cold pressed peanut oil and peanut extract. In the United States, refined peanut oil is exempt from allergen labeling laws.
Peanut flour
Peanut flour is lower in fat than peanut butter, and is popular with chefs because its high protein content makes it suitable as a flavor enhancer. Peanut flour is used as a gluten-free solution.
Boiled peanuts
Boiled peanuts are a popular snack in the southern United States, as well as in India and China. Peanuts are also used in the Mali meat stew maafe, and in many sauces for South American meat dishes, especially rabbit.
Malnutrition
Peanuts are used to help fight malnutrition. Plumpy Nut and Medika Mamba are high protein, high energy and high nutrient peanut-based pastes that were developed to be used as a therapeutic food to aid in famine relief. Organizations like the World Health Organization, UNICEF, Project Peanut Butter and Doctors Without Borders have used these products to help save malnourished children in developing countries.
Peanuts can be used like other legumes and grains to make a lactose-free milk-like beverage, peanut milk. Peanut plant tops are used for hay.
Low grade or culled peanuts not suitable for the edible market are used in the production of peanut oil. The protein cake (oilcake meal) residue from oil processing is used as an animal feed and as a soil fertilizer. Low grade peanuts are also widely sold as a garden bird feed.
Peanuts have a variety of industrial end uses. Paint, varnish, lubricating oil, leather dressings, furniture polish, insecticides, and nitroglycerin are made from peanut oil. Soap is made from saponified oil, and many cosmetics contain peanut oil and its derivatives. The protein portion of the oil is used in the manufacture of some textile fibers. Peanut shells are used in the manufacture of plastic, wallboard, abrasives, fuel, cellulose (used in rayon and paper) and mucilage (glue). Rudolf Diesel ran some of the first engines that bear his name on peanut oil and it is still seen as a potentially useful fuel.
Health benefits
Peanuts are rich in nutrients, providing over 30 essential nutrients and phytonutrients. Peanuts are a good source of niacin, folate, fiber, magnesium, vitamin E, manganese and phosphorus. They also are naturally free of trans-fats and sodium, and contain about 25% protein (a higher proportion than in any true nut).
Trade
The major producers/exporters of peanuts are the United States, Argentina, Sudan, Senegal, and Brazil. These five countries account for 71% of total world exports. In recent years, the United States has been the leading exporter of peanuts. The major peanut importers are the European Union (EU), Canada, and Japan. These three areas account for 78% of the world's imports.
Although India and China are the world's largest producers of peanuts, they account for a small part of international trade because most of their production is consumed domestically as peanut oil. Exports of peanuts from India and China are equivalent to less than 4% of world trade.
Ninety percent of India's production is processed into peanut oil. Only a nominal amount of hand-picked select-grade peanuts are exported. India prohibits the importation of all oil seeds, including peanuts.
The European Union is the largest consuming region in the world that does not produce peanuts. All of its consumption is supplied by imports. Consumption of peanuts in the EU is primarily as food, mostly as roasted-in-shell peanuts and as shelled peanuts used in confectionery and bakery products.
The average annual U.S. imports of peanuts are less than 0.5% of U.S. consumption. Two thirds of U.S. imports are roasted, unshelled peanuts. The major suppliers are Taiwan, Malaysia, Hong Kong, Mainland China, and Canada. The principal suppliers of shelled peanut imports are Argentina and Canada. Most of Canada's peanut butter is processed from Chinese peanuts. Imports of peanut butter from Argentina are in the form of a paste and must be further processed in the U.S. Other minor suppliers of peanut butter include Malawi, China, India, and Singapore.
Approximately 50% of all peanuts produced in the United States are grown within a 100 mi (160 km) radius of Dothan, Alabama. Dothan is home to the National Peanut Festival established in 1938 and held each fall to honor peanut growers and celebrate the harvest.