Botanical Name :Arachis hypogaea
Species: A. hypogaea
Bengali Name: China badam
Habitat :The peanut plant (Arachis hypogea) is a legume that is native to South America.The cultivated peanut was probably first domesticated in the valleys of Perú. (it now grows in warm areas around the world).
The peanut is in “bean” family (Fabaceae). It is an annual herbaceous plant growing 30 to 50 cm. The leaves are opposite, pinnate with four leaflets (two opposite pairs; no terminal leaflet), each leaflet 1 to 7 cm. long and 1 to 3 cm. broad. The flowers are a typical peaflower in shape, 2 to 4 cm. across, yellow with reddish veining. After pollination, the fruit develops into a legume 3 to 7 cm. long, containing 1 to 4 seeds, which forces its way underground to mature. Hypogaea means “under the earth.”
The peanut was introduced to China by Portuguese traders in the 17th century and another variety by American missionaries in the 19th century.
They became popular and are featured in many Chinese dishes, often being boiled. During the 1980s peanut production began to increase greatly so that as of 2006 China was the world’s largest peanut producer. A major factor in this increase was the household-responsibility system, which moved financial control from the government to the farmers.
The 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 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.
After the peanuts have dried sufficiently, they are threshed, removing the peanut pods from the rest of the bush
Peanuts are found in a wide range of grocery products.Popular confections include salted peanuts, peanut butter (sandwiches, candy bars, and cups), peanut brittle, and shelled nuts (plain/roasted). 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. 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 typically eaten as a snack in the southern United States where most peanuts are grown. More recently, fried peanut recipes have emerged – allowing both shell and nut to be eaten. Peanuts are also used in cosmetics, nitroglycerin, plastics, dyes and paints (see George Washington Carver, who described a large amount of uses for peanuts).
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 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 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.
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 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 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).
While peanuts are considered high in fat, they primarily contain “good” fats also known as unsaturated fats. One serving of peanuts contains 11.5 g unsaturated fat and 2 g of saturated fat. In fact, peanuts have been linked well enough to their heart-healthy benefits. In 2003, the Food and Drug Administration released a health claim recognizing peanuts in helping maintain one’s cholesterol:
Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of most nuts, including peanuts as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.
Some brands of peanut butter are fortified with omega-3 fatty acid in the form of flaxseed oil to balance the ratio of omega-3 to omega-6 fatty acids.
Peanuts are a good source of niacin, and thus contribute to brain health and blood flow.
Recent research on peanuts and nuts in general has found antioxidants and other chemicals that may provide health benefits. New research shows peanuts rival the antioxidant content of many fruits. Roasted peanuts rival the antioxidant content of blackberries and strawberries, and are far richer in antioxidants than carrots or beets. Research conducted by a team of University of Florida scientists, published in the journal Food Chemistry, shows that peanuts contain high concentrations of antioxidant polyphenols, primarily a compound called p-coumaric acid, and that roasting can increase peanuts’ p-coumaric acid levels, boosting their overall antioxidant content by as much as 22%.
The seeds have been used in folk medicine as an anti-inflammatory, aphrodisiac and decoagulant. Peanuts play a small role in various folk pharmacopoeias. In China the nuts are considered demulcent, pectoral, and peptic; the oil aperient and emollient, taken internally in milk for treating gonorrhea, externally for treating rheumatism. In Zimbabwe the peanut is used in folk remedies for plantar warts. Hemostatic and vasoconstrictor activity are reported. The alcoholic extract is said to affect isolated smooth muscles and frog hearts like acetylcholine. The alcoholic lipoid fraction of the seed is said to prevent hemophiliac tendencies and for the treatment of some blood disorders (mucorrhagia and arthritic hemorrhages) in hemophilia. The red papery skins are one of the best dietary sources of oligomeric procyanidins, which are compounds that decrease capillary fragility and permeability, helping to prevent and treat varicose veins
Peanuts are a significant source of resveratrol, a chemical studied for potential anti-aging effects and also associated with reduced cardiovascular disease and reduced cancer risk.
It has recently been found that the average amount of resveratrol in one ounce of commonly eaten peanuts (15 whole peanut kernels) is 73 g.
Peanuts are a source of coenzyme Q10, as are oily fish, beef, soybeans and spinach.
HEALTH ALART ->
Some people (0.6–1% of the US population) have mild to severe allergic reactions. For some people with peanut allergy, exposure can cause fatal anaphylactic shock. For these individuals, eating a small amount of peanut or just breathing the dust from peanuts can cause a fatal reaction. An allergic reaction also can be triggered by eating foods that have been processed with machines that have previously processed peanuts, making the avoidance of such food difficult.
A theory of the development of peanut allergy has to do with the way peanuts are processed in North America versus other countries, like China and India. Peanuts are widely eaten in China and India, but peanut allergies are almost unheard of there. According to a 2003 study, roasting peanuts, as more commonly done in North America, causes the major peanut allergen Ara h2 to become a stronger inhibitor of the digestive enzyme trypsin, making it more resistant to digestion. Additionally, this allergen has also been shown to protect Ara h1, another major peanut allergen, from digestion—a characteristic further enhanced by roasting.
Another theory, called the hygiene hypothesis, states that a lack of early childhood exposure to infectious agents like germs and parasites could be causing the increase of food allergies.
Recent (2008) studies comparing age of peanut introduction in Great Britain with introduction in Israel appear to show that delaying exposure to peanuts can dramatically increase the risk of developing peanut allergies.
Results from some animal studies (and limited evidence from human subjects) suggest that the dose of peanuts is an important mediator of peanut sensitisation and tolerance; low doses tend to lead to sensitisation and higher doses tend to lead to tolerance.
Though the allergy can last a lifetime, another 2003 study indicates that 23.3% of children will outgrow a peanut allergy.
Peanut allergy has been associated with the use of skin preparations containing peanut oil among children, but the evidence is not regarded as conclusive. Peanut allergies have also been associated with family history and intake of soy products.
Some school districts in the U.S.A have banned peanuts. There are experimental techniques which appear to have desensitized some allergic individuals. The most popular technique, oral immunotherapy, works to create desensitization in those peanut allergic by feeding them small amounts of peanut until their body becomes desensitized.
Research indicates that refined peanut oil will not cause allergic reactions in most people with peanut allergies. However, crude (unrefined) peanut oils are strongly flavoured, and have been shown to contain protein, which may cause allergic reactions.
In a randomized, double-blind crossover study, 60 people with proven peanut allergy were challenged with both crude peanut oil and refined peanut oil. The authors conclude, “Crude peanut oil caused allergic reactions in 10% of allergic subjects studied and should continue to be avoided.” They also state, “Refined peanut oil does not seem to pose a risk to most people with peanut allergy.” However, they point out that refined peanut oil can still pose a risk to peanut-allergic individuals if oil that has previously been used to cook foods containing peanuts is reused.
Some progress is possibly being made in the UK, where researchers at Cambridge are studying the effectiveness of the desensitization technique.
Contamination and aflatoxin
Peanuts may be contaminated with the mold Aspergillus flavus which produces a carcinogenic substance called aflatoxin. Lower quality specimens, particularly where mold is evident, are more likely to be contaminated. USDA tests every truckload of raw peanuts for aflatoxin; any containing aflatoxin levels of more than 20 parts per billion are destroyed. The peanut industry has manufacturing steps in place to ensure all peanuts are inspected for aflatoxin. Peanuts are also processed at a high temperature to ensure any microorganisms are killed.
The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.
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