PEANUTS RED RAW
The peanut, or groundnut (Arachis hypogaea), is a species in the legume or "bean" family (Fabaceae). The peanut was probably first domesticated and cultivated in the valleys of Paraguay. It is an annual herbaceous plant growing 30 to 50 cm (1.0 to 1.6 ft) tall. The leaves are opposite, pinnate with four leaflets (two opposite pairs; no terminal leaflet), each leaflet is 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 (0.8 to 1.6 in) (¾ to 1½ in) across, yellow with reddish veining. Hypogaea means "under the earth"; after pollination, the flower stalk elongates causing it to bend until the ovary touches the ground. Continued stalk growth then pushes the ovary underground where the mature fruit develops into a legume pod, the peanut – a classical example of geocarpy. Pods are 3 to 7 cm (1.2 to 2.8 in) long, containing 1 to 4 seeds.
Peanuts are known by many other local names such as earthnuts, ground nuts, goober peas, monkey nuts, pygmy nuts and pig nuts. Despite its name and appearance, the peanut is not a nut, but rather a legume.
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 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.
Although the peanut was mainly a garden crop for much of the colonial period of North America, it was mostly used as animal feed stock until the 1930s. In the United States, a US Department of Agriculture program (see below) to encourage agricultural production and human consumption of peanuts was instituted in the late 19th and early 20th centuries. George Washington Carver is well known for his participation in that program in which he developed hundreds of recipes for peanuts.
Cultivation and uses
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 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. They need an acidic soil to grow preferably with 5.9-7 pH. 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 soil. This allows the peanuts to dry slowly to a bit less than a third of their original moisture level over a period of three to four days. Traditionally, peanuts were pulled and inverted by hand.
After the peanuts have dried sufficiently, they are threshed, removing the peanut pods from the rest of the bush.