Tuberous edible perennial plant (Manihot esculenta) of the spurge family, from the New World tropics. It is cultivated for its tuberous roots, from which cassava flour, breads, tapioca, a laundry starch, and an alcoholic beverage are derived. It has conspicuous, almost palmate (fan-shaped) leaves and fleshy roots. Different varieties range from low herbs through many-branched shrubs to slender, unbranched trees adapted to diverse habitats.
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The cassava root is long and tapered, with a firm homogeneous flesh encased in a detachable rind, about 1 mm thick, rough and brown on the outside, just like a potato. Commercial varieties can be 5 to 10 cm in diameter at the top, and 50 to 80 cm long. A woody cordon runs along the root's axis. The flesh can be chalk-white or yellowish. The cassava plant gives the highest yield of food energy per cultivated area per day among crop plants, except possibly for sugarcane. Cassava roots are very rich in starch, and contain significant amounts of calcium (50 mg/100g), phosphorus (40 mg/100g) and vitamin C (25 mg/100g). However, they are poor in protein and other nutrients. In contrast, cassava leaves are a good source of protein if supplemented with the amino acid methionine despite containing cyanide.
Wild populations of M. esculenta subspecies flabellifolia, shown to be the progenitor of domesticated cassava, are centered in west-central Brazil where it was likely first domesticated no more than 10,000 years BP. By 6,600 BC, manioc pollen appears in the Gulf of Mexico lowlands, at the San Andres archaeological site. The oldest direct evidence of cassava cultivation comes from a 1,400 year old Maya site, Joya de Ceren, in El Salvador. although the species Manihot esculenta likely originated further south in Brazil and Paraguay. With its high food potential, it had become a staple food of the native populations of northern South America, southern Mesoamerica, and the West Indies by the time of the Spanish conquest, and its cultivation was continued by the colonial Portuguese and Spanish. Forms of the modern domesticated species can be found growing in the wild in the south of Brazil. While there are several wild Manihot species, all varieties of M. esculenta are cultigens.
World production of cassava root was estimated to be 184 million tonnes in 2002, the majority of production is in Africa where 99.1 million tonnes were grown, 51.5 million tonnes were grown in Asia and 33.2 million tonnes in Latin America and the Caribbean. However, based on the statistics from the FAO of the United Nations, Thailand is the largest exporting country of Dried Cassava with a total of 77% of world export in 2005. The second largest exporting country is Vietnam, with 13.6%, followed by Indonesia (5.8%) and Costa Rica (2.1%).
In many places in the Americas, yuca was the staple food. This translated into many images of yuca being used in pre-Colombian art. The Moche people often depicted yuca in their ceramics.
The leaves cannot be consumed raw since they contain free and bound cyanogenic glucosides. These are converted to cyanide in the presence of linamarase, a naturally occurring enzyme in cassava. The roots, however, are eaten raw everywhere in Africa. Cassava varieties are often categorized as either "sweet" or "bitter", signifying the absence or presence of toxic levels of cyanogenic glucosides. The so-called "sweet" (actually "not bitter") cultivars can produce as little as 20 milligrams of cyanide (CN) per kilogram of fresh roots, while "bitter" ones may produce more than 50 times as much (1 g/kg). Cassavas grown during drought are especially high in these toxins. One dose of pure cassava cyanogenic glucoside (40mg) is sufficient to kill a cow.
Societies which traditionally eat cassava generally understand that soaking and/or cooking is necessary to avoid getting sick. However, problems do occur - konzo (also called mantakassa) is a paralytic neurological disease associated with several weeks of almost exclusive consumption of insufficiently processed bitter cassava. Dr Jasson Ospina, an Australian plant chemist, has developed a simple method to reduce the cyanide content of cassava flour. The method involves mixing the flour with water into a thick paste and then letting it stand in the shade for five hours in a thin layer spread over a basket, allowing an enzyme in the flour to break down the cyanide compound. The cyanide compound produces hydrogen cyanide gas, which escapes into the atmosphere, reducing the amount of poison by up to five-sixths and making the flour safe for consumption the same evening. This method is currently being promoted in rural African communities that are dependent on cassava.
For some smaller-rooted "sweet" varieties, cooking is sufficient to eliminate all toxicity. The larger-rooted "bitter" varieties used for production of flour or starch must be processed to remove the cyanogenic glucosides. The large roots are peeled and then ground into flour, which is then soaked in water, squeezed dry several times, and toasted. The starch grains that float to the surface during the soaking process are also used in cooking. The flour is used throughout the Caribbean. The traditional method used in West Africa is to peel the roots and put them into water for 3 days to ferment. The roots then are dried or cooked. In Nigeria and several other west African countries, including Ghana, Benin, Togo, Ivory Coast and Burkina Faso, they are usually grated and lightly fried in palm oil to preserve them. The result is a foodstuff called 'Gari'. Fermentation is also used in other places such as Indonesia.
The reliance on cassava as a food source and the resulting exposure to the goitrogenic effects of thiocyanate has been responsible for the endemic goitres seen in the Akoko area of southwestern Nigeria.
The juice of the bitter cassava, boiled to the consistence of thick syrup and flavored with spices, is called Cassareep. It is used as a basis for various sauces and as a culinary flavoring, principally in tropical countries. It is exported chiefly from Guyana.
The leaves can be pounded to a fine chaff and cooked as a palaver sauce in Sierra Leone, usually with palm oil but vegetable oil can also be used. Palaver sauces contain meat and fish as well. It is necessary to wash the leaf chaff several times to remove the bitterness.
In many countries, significant research has begun to evaluate the use of cassava as an ethanol biofuel.
In China, dried tapioca are used among other industrial applications as raw material for the production of consumable alcohol and emerging non-grain feedstock of ethanol fuel, which is a form of renewable energy to substitute petrol (gasoline). Under the Development Plan for Renewable Energy in the 11th Five-Year Plan in China, the target is to increase the application of ethanol fuel by non-grain feedstock to 2 million tonnes, and that of bio-diesel to 200 thousand tonnes by 2010. This will be equivalent to a substitute of 10 million tonnes of petroleum. As a result, cassava (tapioca) chips have gradually become a major source for ethanol production.
The root, in its boiled and peeled form, is also present in the typical Puerto Rican stew, the Sancocho, together with plantains, potatoes, yautía, among other vegetables (it can also be eaten singly as an alternative to boiled potatoes or plantains). It can be grounded and used as a paste (masa) to make a typically Puerto Rican Christmas favorite dish called "Pasteles". It is somewhat similar to Mexican tamales in appearance, but is made with root vegetables, plantains or yuca, instead of corn. Pasteles are rectangular and have a meat filling in the center, chicken or pork. They are wrapped in a plantain leaf. "Masa" made from cassava is also used for "alcapurrias". These are shaped like lemons and are filled with meat similar to the pasteles but they are fried instead.
Using the traditional method of frying potato chips, bagged 'cassava chips' are produced and exported.
In the coastal region, is known especially in the form of "Bollo de yuca" (a kind of bread) or "enyucados". "Bollo de yuca" is a dough made of ground yuca that is wrapped in aluminum foil and then boiled, and is served with butter and cheese. "Enyucado" is a dessert made of ground boiled yuca, anise, sugar, and sometimes guava jam. In the caribbean region of Colombia it is also eaten roasted, fried or boiled with soft homemade cheese or cream cheese and mainly as guarnition of fish dishes.
In Suriname, cassava is widely used by the Creole, Indian, Javanese and indigenous population. Telo is a popular dish which is salted fish and cassava, where the cassava is steamed and deepfried. Other dishes with cassava include soups, dosi and many others.
Ecuadorians also make bread from yuca flour and mashed yuca rood, including the extremely popular Bolitos de Yuca or Yuquitas which range from balls of yuca dough formed around a heart of fresh cheese and deep-fried (found primarily in the north), to the simpler variety typical to Colombia which are merely baked balls of yuca dough. Yuca flour is sold in most markets.
In the Amazon Basin, yuca is a main ingredient in chicha - a traditional fermented drink produced by the indigenous Quichua population.
Yuca leaves, steamed, are part of the staple diet of the indigenous population in all areas where it is grown.
In the humid and sub-humid areas of tropical Africa, cassava is either a primary staple food or a secondary co-staple. Nigeria is the world's largest producer of cassava. In West Africa, particularly in Nigeria and Sierra Leone, cassava is commonly prepared as eba or garri. The cassava is grated, pressed, fermented and fried then mixed with boiling water to form a thick paste. In West Africa the cassava root is pounded, mixed with boiling water to form a thick paste and cooked as eba. Historically, people economically forced to depend on cassava risk chronic poisoning diseases, such as tropical ataxic neuropathy (TAN), or such malnutrition diseases as kwashiorkor and endemic goitre. However, the price of cassava has risen significantly in the last half decade and lower-income people have turned to other carbohydrate-rich foods like rice and spaghetti.
In Central Africa, cassava is traditionally processed by boiling and mashing. The resulting mush can be mixed with spices and then cooked further or stored. A popular snack is made by marinating cassava in salted water for a few days and then grilling it in small portions.
In Tanzania and Kenya, cassava is known as mihogo in Swahili. Though the methods of cooking cassava vary from region to region, the main method is simply frying it. The skin of the root is removed and the remains are sectioned into small bite-size chunks that can then be soaked in water to aid in frying. Thereafter, the chunks are fried and then served, sometimes with a chili-salt mixture. This fried cassava is a very common street food as it is relatively cheap to buy, easy to prepare and good to eat.
Cassava flour can also be made into a staple food with a consistency like polenta or mashed potatoes. The Swahili name for it is ugali while the Kikuyu name for it is mwanga). It's also called fufu in Lingala.
Residents in the Sub-Saharan nation of the Central African Republic have developed multiple, unique ways of utilizing the abundant cassava plant. In addition to the methods described above, local residents fry thin slices of the cassava root, resulting in a crunchy snack similar in look and taste to potato chips.
The root can be pounded into flour and made into bread or cookies. Many recipes have been documented and tested with groups of women in Mozambique and Zambia.This flour can also be mixed with precise amounts of salt and water to create a heavy liquid used as white paint in construction.
The cassava leaf is also soaked and boiled for extended periods of time to remove toxins and then eaten. Known as gozo in Sango and pondu in Lingala, the taste is similar to spinach.
In the state of Kerala, India, cassava is a secondary staple food. Boiled cassava is normally eaten with fish curry (kappayum meenum in Malayalam which literally means casava with fish) or meat, and is a traditional favorite of many Keralites. Kappa biriyani — cassava mixed with meat is a popular dish in central Kerala. In Tamil Nadu, the National Highway 68 between Thalaivasal and Attur has many cassava processing factories (local name Sago Factory) alongside it - indicating an abundance of it in the neighborhood. In Tamil Nadu it is called Kappa Kellangu or Marchini Kellangu. Cassava is widely cultivated and eaten as a staple food in Andhra Pradesh. The household name for processed cassava is saggu biyyam. Cassava is also deep fried in oil to make tasty homemade crisps,then sprinked with flaked chillies or chilli powder and salt for taste.It is known as Mara Genasu in Kannada.
Cassava Pearls {Sabu-Daana) is cassava-root starch and is used for making sweet milk puddings.
The leaves are also cooked and eaten.
Maniyok Curry is a good side dish when taking rice, a Sri Lankan staple food. There is belief among Sri Lankans that one should not take Maniyok together with Ginger which will cause food poisoning. Leaves of the plant are also prepared as side dish and called "Malluma". Dried, powdered, and starched Tapioca are widely used in Sri Lanka.
Cassava's name in Vietnamese is "Khoai Mì" (Southern). It is planted almost everywhere in Vietnam and its root is amongst the cheapest sources of food there. The fresh roots are sliced into thin pieces and then dried in the sun for easy storage. Tapioca is the most valuable product from processed cassava roots there.
Cassava is used worldwide for animal feed as well.
In Africa the cassava mealybug (Phenacoccus manihoti) and cassava green mite (Mononychellus tanajoa) can cause up to 80% crop loss, which is extremely detrimental to the production of subsistence farmers. These pests were rampant in the 1970s and 1980s but were brought under control following the establishment of the Biological Control Centre for Africa of the IITA. The Centre investigated biological control for cassava pests; two South American natural enemies Apoanagyrus lopezi (a parasitoid wasp) and Typhlodromalus aripo (a predatory mite) were found to effectively control the cassava mealybug and the cassava green mite respectively.
The cassava mosaic virus causes the leaves of the cassava plant to wither, limiting the growth of the root. The virus is spread by the whitefly and by the transplanting of diseased plants into new fields. Sometime in the late 1980s, a mutation occurred in Uganda that made the virus even more harmful, causing the complete loss of leaves. This mutated virus has been spreading at a rate of 50 miles per year, and as of 2005 may be found throughout Uganda, Rwanda, Burundi, the Democratic Republic of the Congo and the Republic of the Congo.