The peanut (Arachis hypogaea), also known as the groundnut, goober (US), pindar (US), or monkey nut (UK), is a legume crop grown primarily for its edible seeds. It is commonly grown in the tropics and subtropics, with both small and large commercial farmers relying on it. Peanut pods grow underground (geocarpy) rather than above ground, which is uncommon among legume crop plants.
The peanut is a member of the Fabaceae (or Leguminosae) botanical family, also known as the legume, bean, or pea family. Peanuts have a flavor and nutrient profile that is comparable to “tree nuts” like walnuts and almonds, and as a culinary nut, they are often eaten in similar ways in Western cuisines. “A fruit whose ovary wall becomes hard at maturity,” according to the botanical description of a nut. The peanut is not a nut according to this criterion. Peanuts, on the other hand, are often referred to as “nuts” in the food world and in everyday English.
Peanuts are an annual herbaceous plant that grows to a height of 30 to 50 cm (12 to 20 in). The leaves are opposite and pinnate, with four leaflets (two opposite pairs; no terminal leaflet); each leaflet is 1 to 7 centimetres (12 to 14 inches) long and 1 to 3 centimetres (1/2 to 1/4 inches) broad. The leaves, like those of many other legumes, are nyctinastic, meaning they close at night and have “sleep” motions.
The flowers are yellowish orange with reddish veining and measure 1 to 1.5 cm (3/8 to 5/8 in) wide. They occur in axillary clusters on the above-ground stems and last just one day. The ovary is situated at the base of the flower stem, which is essentially a long floral cup.
Peanut fruits develop underground, an unusual feature known as geocarpy. A short stalk at the base of the ovary (often called a gynophore but simply appearing to be part of the ovary itself) elongates after fertilization to form a thread-like structure known as a “peg.” This peg falls into the earth, allowing the fruit to expand underground. These pods (technically known as legumes) vary in size from 3 to 7 centimetres (1 to 3 in) in length and usually contain one to four seeds. The peanut fruit’s shell is largely made up of mesocarp, with numerous long veins running the length of it.
Peanuts thrive in light, sandy loam soil with a pH between 5.9 and 7. Peanuts benefit less if not at all from nitrogen-containing fertilizer because of their ability to fix nitrogen, and they increase soil fertility when nodulated properly. As a result, they’re useful in crop rotations. In addition, rotations increase the yield of the peanut crop by reducing pathogens, rodents, and weeds. For good yields, adequate amounts of phosphorus, potassium, calcium, magnesium, and micronutrients are also needed. Peanuts need warm conditions during the growing season to flourish. They can be grown with as little as 350 mm (14 in) of water, but they require at least 500 mm for the best yields (20 in). Harvest is typically 90 to 130 days after planting for subspecies A. h. fastigiata types, and 120 to 150 days after planting for subspecies A. h. hypogaea types, depending on growing conditions and cultivar of peanut. [ Subspecies A. h. hypogaea species yield more and are typically favoured in areas with long growing seasons.
Peanut plants continue to grow flowers as pods form, so some pods are immature even though they are ready to harvest. Harvesting at the right time is critical for maximizing yield. If you harvest too early, there will be an abundance of unripe pods; if you harvest too late, the pods will break off at the stalk and fall to the ground. The entire plant, including the majority of the roots, is cut from the soil for harvesting. The pods are constricted between seeds and filled with a network of elevated veins.
There are two phases of harvesting. In mechanized processes, a machine drills into the soil just below the surface of the peanut pods to cut off the main root of the peanut plant. To hold the peanuts out of the dirt, the machine raises the “bush” off the ground and shakes it, and inverts the bush, leaving the plant upside down on the ground. This helps the peanuts to dry steadily over three to four days to a little less than a third of their original moisture level. Peanuts were usually pulled and inverted by hand.
The peanuts are threshed after they have dried enough, separating the peanut pods from the rest of the bush. It is important that peanuts are well dried and processed in a dry environment. They can become infected by the mold fungus Aspergillus flavus if there is too much moisture in them or if the storage conditions are bad. Many strains of this fungus develop aflatoxins, which are extremely toxic and carcinogenic.
Types (Species) of Peanuts (Groundnuts)
Many different peanut cultivars are cultivated all over the world. For unique characteristics such as taste, oil content, size, shape, and disease resistance, certain cultivar classes are favored. The various types of peanuts are described below:
Spanish Group Peanuts
The small Spanish types are grown in South Africa, and in the southwestern and southeastern United States. Until 1940, Spanish varieties accounted for 90% of peanuts grown in Georgia, but since then, the trend has been toward larger-seeded, higher-yielding, disease-resistant cultivars. The oil content of Spanish peanuts is greater than that of other types of peanuts. Cultivars of the Spanish group include ‘Dixie Spanish’, ‘Improved Spanish 2B’, ‘GFA Spanish’, ‘Argentine’, ‘Spantex’, ‘Spanette’, ‘Shaffers Spanish’, ‘Natal Common (Spanish)’, “White Kernel Varieties’, ‘Starr’, ‘Comet’, ‘Florispan’, ‘Spanhoma’, ‘Spancross’, ‘OLin’, ‘Tamspan 90’, ‘AT 9899–14’, ‘Spanco’, ‘Wilco I’, ‘GG 2’, ‘GG 4’, ‘TMV 2’, and ‘Tamnut 06’.
Runner Group Peanuts
The production of Runner group peanuts has risen in the southeastern United States since 1940. When compared to Spanish types, this change is due to improved taste, roasting features, and yields, contributing to food manufacturers’ preference for use of peanut butter and salted nuts. Georgia’s production is now almost entirely of the Runner type. Cultivars of Runners include ‘Southeastern Runner 56-15’, ‘Dixie Runner’, ‘Early Runner’, ‘Virginia Bunch 67’, ‘Bradford Runner’, ‘Egyptian Giant’ (also known as ‘Virginia Bunch’ and ‘Giant’), ‘Rhodesian Spanish Bunch’ (Valencia and Virginia Bunch), ‘North Carolina Runner 56-15’, ‘Florunner’, ‘Virugard’, ‘Georgia Green’, ‘Tamrun 96’, ‘Flavor Runner 458’, ‘Tamrun OL01’, ‘Tamrun OL02’ ‘AT-120’, ‘Andru-93’, ‘Southern Runner’, ‘AT1-1’, ‘Georgia Brown’, ‘GK-7’, and ‘AT-108’.
Virginia Group Peanuts
Peanuts from the Virginia group, which have big seeds, are grown in Virginia, North Carolina, Tennessee, Texas, New Mexico, Oklahoma, and parts of Georgia. They’re becoming more common as a result of increased demand for large peanuts for processing, particularly for salting, confections, and roasting in the shells. Peanuts in the Virginia group mature in either a bunch or a running habit. The bunch is upright to spreading in nature. It grows to a height of 45–55 cm (18–22 in) and a spread of 70–80 cm (28–31 in), with 80–90 cm (31–35 in) rows that seldom cover the ground. The pods are produced within a 5 to 10 cm (2 to 4 in) radius of the plant’s base. Cultivars of Virginia type peanuts include ‘NC 7’, ‘NC 9’, ‘NC 10C’, ‘NC-V 11’, ‘VA 93B’, ‘NC 12C’, ‘VA-C 92R’, ‘Gregory’, ‘VA 98R’, ‘Perry’, ‘Wilson, ‘Hull’, ‘AT VC-2′ and’ Shulamit’.
Valencia Group Peanuts
Peanuts from the Valencia group are coarse, with heavy reddish stems and broad leaves. Large-scale commercial production is concentrated in West Texas’ South Plains and eastern New Mexico’s Portales area, but they are also grown on a small scale elsewhere in the South as the best-flavored and favored variety for boiled peanuts. They are relatively tall, standing at 125 cm (49 in) tall with a 75 cm spread (30 in). Peanut pods grow on pegs that arise from the main stem and side branches. The bulk of the pods are clustered around the plant’s base, with just a handful found a few inches apart. Valencia varieties have three to five seeds and a flat shell with no constriction between the seeds. The seeds are oval and packed into the pods closely. 0.4 to 0.5 g is the normal seed weight. This variety is widely used in the selling of roasted and salted in-shell peanuts, as well as peanut butter. Varieties include ‘Valencia A’ and ‘Valencia C’.
Tennessee Red and Tennessee White Groups Peanuts
Except for the color of the seed, both are identical. The plants are similar to Valencia types, with the exception that the stems are green to greenish brown and the pods are rough, uneven, and have a lower proportion of kernels.
Historical Background (Origin) of Peanuts (Groundnuts)
Cultivated peanuts (A. hypogaea) are the product of a cross between two wild peanut varieties, A. duranensis and A. ipaensis. The combination may have been sterile at first, but natural chromosome doubling recovered its fertility, resulting in an amphidiploid or allotetraploid. According to genetic research, the hybridization may have only happened once, resulting in A. monticola, a wild type of peanut found in a few isolated areas in northwestern Argentina, or in southeastern Bolivia, where the peanut landraces with the most wild-like characteristics are grown today, and through artificial selection to A. hypogaea.
A. hypogaea was significantly different from its wild ancestors after being domesticated by artificial selection. Domesticated plants have a distinct pod structure and bigger seeds, as well as being bushier and more compact. Cultivation expanded from this primary center of origin in Peru, Ecuador, Brazil, Paraguay, and Uruguay, forming secondary and tertiary centers of diversity. Thousands of peanut landraces have evolved over time, and they are divided into six botanical varieties and two subspecies (as listed in the peanut scientific classification table). A. h. fastigiata varieties have a more upright growing habit and shorter harvest periods than subspecies A. h. fastigiata types. A. h. hypogaea forms spread out further on the ground and have longer harvest periods than other subspecies.
Around 7,600 years ago, archeological remnants of pods were discovered, probably from a wild plant that was cultivated or A. hypogaea in the early stages of domestication. They were discovered in Peru, where the dry climate is conducive to the preservation of organic material. Peanut farming almost definitely predated this in the center of production, where the atmosphere is moister. Peanuts were portrayed in art by many pre-Columbian peoples, including the Moche. Cultivation had long been practiced in Mesoamerica before the arrival of the Spaniards. The conquistadors encountered the tllcacahuatl (the plant’s Nahuatl name) being traded in Tenochtitlan’s marketplace. European traders later distributed the peanut around the world, and it is now commonly cultivated in tropical and subtropical regions. In West Africa, it largely replaced the Bambara groundnut, a crop plant from the same family of underground seed pods. It became an agricultural mainstay in Asia, and the country is now the world’s largest producer.
Nutritional Value (Composition) of Peanuts (Groundnuts)
Peanuts are highly nutritious. Peanuts contain 2,385 kilojoules (570 kilocalories) of food energy in a 100-gram (3.5-ounce) reference serving and are an outstanding source (defined as more than 20% of the Daily Value, DV) of many B vitamins, vitamin E, dietary minerals like manganese (95 percent DV), magnesium (52 percent DV), and phosphorus (48 percent DV), and dietary fiber. They also have a higher protein content than many tree nuts, at around 25 g per 100 g serving. Polyphenols, polyunsaturated and monounsaturated fats, phytosterols, and dietary fiber are both found in identical quantities in peanuts as they are in other tree nuts.
Peanut oil is 46 percent monounsaturated fats (primarily oleic acid), 32 percent polyunsaturated fats (primarily linoleic acid), and 17 percent saturated fats, making it a popular cooking and salad oil (primarily palmitic acid).
Uses of Peanuts (Groundnuts)
Peanuts are used in a variety of ways. Some of the most remarkable used of peanuts are as shown below:
Peanuts are usually prepared by dry roasting. Dry peanuts can be roasted in the shell or shelled in a home oven by spreading them out one layer deep in a pan and baking them for 15 to 20 minutes (shelled) or 20 to 25 minutes (shelled) at 177°C (351°F) (in shell).
In India, China, West Africa, and the southern United States, boiled peanuts are a popular snack. Boiled peanuts are commonly cooked in briny water and sold in streetside stands in the United States’ South.
Because of its moderate taste and high smoke point, peanut oil is often used in cooking. It is considered healthier than saturated oils owing to its high monounsaturated quality and susceptibility to rancidity. Aromatic roasted peanut oil, distilled peanut oil, extra virgin or cold-pressed peanut oil, and peanut extract are among the various types of peanut oil.
Peanut butter is a spread or food paste made from ground dried roasted peanuts. Salt, sweeteners, and emulsifiers are common additions that change the flavor or texture of the product. Peanut butter is used to make sandwiches and is served on pizza, toast, or crackers (notably the peanut butter and jelly sandwich). It’s also used in granola bars with peanut butter taste, as well as croissants and other pastries.
Commercially available peanut protein concentrates and isolates are manufactured from defatted peanut flour in a number of ways. Peanut flour concentrates (about 70% protein) are made by extracting the bulk of the oil and water-soluble non-protein components from dehulled kernels. Oil removal techniques include hydraulic pressing, screw pressing, solvent extraction, and pre-pressing accompanied by solvent extraction, followed by protein separation and purification.
Peanuts Dishes (Cuisine)
Peanuts are particularly prevalent in Peruvian and Mexican cuisines, which combine indigenous and European ingredients. Picante de cuy, a roasted guinea pig served in a sauce of ground peanuts (South American ingredients) with roasted onions and garlic, is a common traditional dish in Peru (ingredients from European cuisine). In Arequipa, Peru, a dish known as ocopa consists of a smooth sauce made with roasted peanuts and hot peppers (both native to the region), roasted onions, garlic, and oil, and poured over meat or potatoes. A fricassee, which mixes a similar combination of sautéed seafood or boiled and shredded chicken, is another example. These dishes are known as ajes, which means “hot peppers,” and include dishes like aji de pollo and aji de mariscos (seafood ajies can omit peanuts). In Mexico, it’s used to make a variety of popular dishes like encacahuatado (chicken in peanut sauce) and as a key ingredient in other well-known dishes like red pipián, mole poblano, and oaxacan mole negro.
Similarly, during colonial times in Peru, the Spanish used peanuts to supplement nuts such as almonds and pine nuts, which were scarce locally but were commonly used in Spanish cuisine, and were usually ground or combined with rice, meats, and vegetables for dishes such as rice pilaf.
Peanuts are used in a variety of candies and snacks in the country. In Mexico, they’re commonly used as a snack or candy in a variety of ways, including salty “Japanese” peanuts, praline, enchilados, or in the form of palanqueta, a popular sweet made with peanuts and sugar, and even as peanut marzipan.
In Israel, crunchy coated peanuts, known as kabukim in Hebrew, are a popular snack. Kabukim are commonly available by the pound at corner stores that sell new nuts and seeds, but they are often packaged. Flour, salt, sugar, lecithin, and sesame seeds are widely used in the coating. The name’s origin is uncertain (it may be derived from kabuk which means nutshell or husk in Turkish). “American peanuts” are another crunchy coated peanut type common in Israel. This variety’s covering is finer, but it is more resistant to cracking. In Israel, Bamba puffs are a common snack. They resemble Cheez Doodles in shape, but they’re made of peanuts and corn.
Peanuts are also popular in Southeast Asian cuisine, especially in Malaysia, Vietnam, and Indonesia, where they are usually made into a spicy sauce. Peanuts first arrived in Indonesia from the Philippines, where the legume was transported from Mexico during the Spanish colonial era. Kare-kare, a meat-and-peanut-butter blend, is one Filipino dish that uses peanuts. Apart from being used in dishes, fried shelled peanuts are a popular cheap snack in the Philippines, with the peanuts being eaten plain salted with garlic chips or in a variety of flavors such as adobo and chilli. Gado-gado, pecel, karedok, and ketoprak, vegetable salads mixed with peanut sauce, and satay, a peanut-based sauce, are all popular Indonesian peanut-based dishes.
Peanuts are a light snack on the Indian subcontinent, usually roasted and salted (with the addition of chilli powder), and sold roasted in pods or boiled with salt. Through cooking them with refined sugar and jaggery, they can also be turned into a dessert or sweet snack known as peanut brittle. Roasted, crushed peanuts are used in Indian cuisine to add crunch to salads, and they are often added whole (without pods) to leafy vegetable stews for the same purpose. Cooking with peanut oil is another choice. Most Indians cook with mustard, sunflower, and peanut oil. Groundnut chutney is served with dosa and idli for breakfast in South India. Peanuts are also used in South Indian sweets and savory dishes, as well as as a flavoring in tamarind rice. Kovilpatti is famous for its sweet peanut chikki, also known as peanut brittle, which is used in savory and sweet dishes like Bombay mix.
Peanuts grow well in southern Mali and neighboring Ivory Coast, Burkina Faso, Ghana, Nigeria, and Senegal; peanuts are similar to the Bambara groundnut native to the region in both agricultural and culinary qualities, and West Africans have adopted the crop as a staple. Peanut sauce, which is made with onions, garlic, peanut butter/paste, and vegetables like carrots, cabbage, and cauliflower, can be vegetarian (the peanuts have plenty of protein) or meat-based (usually chicken).
Malian beef stew maafe contains peanuts. Peanut butter is used to make nkate nkwan (peanut butter soup) in Ghana. Peanut candies, nkate cake, and kuli-kuli, as well as other popular foods like oto, can all be made with crushed peanuts. In Nigeria’s “African salad,” peanut butter is included. Peanut powder is a common ingredient in Nigerian and Ghanaian spicy kebab coatings.
Peanuts are a common ingredient in a variety of relishes (side dishes) served with nshima in Malawi and Zambia’s eastern provinces, and these dishes are popular in both countries. Ugandans also make rich peanut butter sauces to eat with rice and other starchy foods. In Luganda-speaking areas of Uganda, groundnut stew is called ebinyebwa and is produced by boiling ground peanut flour with other ingredients including cabbage, mushrooms, dried fish, beef, or other vegetables. Roasted peanuts are sold by street sellers throughout East Africa, often in newspaper cones.
Peanuts are found in candies, desserts, cookies, and other treats in Canada and the United States. They are dry-roasted with or without salt and consumed individually. Peanuts and peanut butter are staples of American diets and are sometimes referred to as “comfort foods” in the United States. Peanut butter is a popular peanut-based food in the United States, accounting for half of all peanut intake. Peanut soup is a common dish on restaurant menus in the Southeast. Peanuts are cooked for several hours in several parts of the United States before tender and moist. Deep-fried peanuts are often served, often in their shells.
Used as Animal Feed
Hay can be made from the tops of peanut plants and crop residues. The residue from oil processing, known as protein cake (oilcake meal), is used as animal feed and soil fertilizer. Groundnut cake is a livestock feed that is mostly used as a protein substitute by cattle. It is a vital and useful feed for all forms of animals, as well as one of the most active ingredients in poultry rations. Any peanuts, such as those in excess of the US peanut quota or those with a higher aflatoxin content than allowed by food regulations, can be fed whole to livestock. Dehulling is often required in the processing of peanuts, and the hulls produced in large quantities by the peanut industry can then be used to feed livestock, especially ruminants.
Peanuts are used in a variety of industrial products. Peanut oil is used to make paint, varnish, lubricating oil, leather dressings, furniture polish, insecticides, and nitroglycerin. Most cosmetics use peanut oil and its derivatives, and soap is manufactured from saponified oil. A part of the protein is used in the production of textile fibers. Plastic, wallboard, abrasives, fuel, cellulose (used in rayon and paper), and mucilage are all made from peanut shells (glue).
Health Benefits of Peanuts (Groundnuts)
Peanuts are known to be consumed throughout the world because of the numerous health benefits derived from the consumption of peanuts. Some of the most remarkable health benefits are as follows:
Regulates Cholesterol Level
People who ate groundnuts on a regular basis have a lower risk of dying from a heart attack or stroke. Peanuts and other nuts can help to reduce LDL cholesterol (bad cholesterol). Peanuts can help reduce plaque formation in blood vessels by lowering bad cholesterol. Groundnut can also help to decrease inflammation in the body, which can lead to heart disease. Groundnuts include resveratrol, which aids in the prevention of heart disease.
Peanuts contain vitamin B3, also known as niacin, which has a number of health benefits, including normal brain function and memory enhancement.
Groundnut also has a high folate content. According to different studies, women who ingested 400 micrograms of folic acid daily before and during early pregnancy had a 70 percent lower chance of delivering a baby born with a severe neural tube defect.
Helps in Weight Management
Peanuts or groundnuts are called energy-dense foods. You can eat less calories later in the day if you use them as a snack. When eaten as a snack, groundnuts developed more feelings of fullness than when eaten with a meal. This will eventually aid in weight loss. Using groundnuts or other nuts in your diet is a perfect way to increase food consumption and palatability without gaining weight.
Peanut consumption has also been attributed to a reduced risk of gallstones. Gallstone disease was found to be rare in men who consumed 5 or more units of nuts a week, including groundnuts. Similarly, women who ate 5 or more nuts a week have a smaller chance of cholecystectomy (removal of gallbladder).
Tryptophan, an integral amino acid needed for the development of serotonin, one of the main brain chemicals involved in mood control, is abundant in groundnuts. When a person is depressed, the amount of serotonin produced by nerve cells in the brain can be reduced. When there is more serotonin in the brain, tryptophan will enhance the antidepressant effects of serotonin.
Boosts Hair Growth
Peanuts contain all of the essential amino acids and proteins, making them a healthy addition to a hair-growth diet.