Cassava

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Cassava
Koeh-090.jpg
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Malpighiales
Family: Euphorbiaceae
Subfamily: Crotonoideae
Tribe: Manihoteae
Genus: Manihot
Species: M. esculenta

Binomial name
Manihot esculenta
Crantz

The cassava, casava, yuca or manioc (Manihot esculenta) is a woody shrub of the Euphorbiaceae (spurge family) native to South America that is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates. Indeed, cassava is the third largest source of carbohydrates for human food in the world, with Africa its largest center of production.[1]

Description

 
Unprocessed cassava root

The 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. 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; raw cassava tastes like a mixture of potato and coconut flesh, it breaks like a carrot, and darkens quickly upon exposure to the air. For this reason, the skinned root must be kept under water until it is ready to be cooked. The root's flavor spoils in a day or so, even if kept unskinned and under refrigeration, which is a problem for supermarkets. A solution is usually to freeze it or seal it in wax.

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.

History and economic impact

 
Cassava in cultivation in Democratic Republic of Congo
 
Cassava output in 2005
 
Yuca. Moche Culture. 100 A.D. Larco Museum Collection.

The oldest evidence of cassava cultivation comes from a 1,400 year old Maya site, Joya de Ceren, in El Salvador.[2] 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.

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.[3]

Farming

Cassava is harvested by hand by raising the lower part of stem and pulling the roots out of the ground, then removing them from the base of the plant . The upper parts of the stems with the leaves are plucked off before harvest. Cassava is propagated by cutting the stem into sections of appoximately 12", these being planted prior to the wet season.

Processing and toxicity

 
Cassava root peeled

The root cannot be consumed raw, since it contains free and bound cyanogenic glucosides which are converted to cyanide in the presence of linamarase, a naturally occurring enzyme in cassava. 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. [4] [5] One dose of pure cassava cyanogenic glucoside (40mg)is sufficient to kill a cow. Konzo (also called mantakassa) is a paralytic neurological disease associated with several weeks of almost exclusive consumption of insufficiently processed bitter cassava. Dr Howard Bradbury, an Australian plant chemist, has developed a simple method to reduce the cyanide content of cassava flour.[6] 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.[7]


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.[8] 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 are dried or cooked. In Nigeria they are usually grated and lightly fried in palm oil to preserve them.

Uses

Cooked in various ways, cassava is used in a great variety of dishes. The soft-boiled root has a delicate flavor and can replace boiled potatoes in many uses: as an accompaniment for meat dishes, or made into purées, dumplings, soups, stews, gravies, etc.. Deep fried (after boiling or steaming), it can replace fried potatoes, with a distinctive flavor. Tapioca and foufou are made from the starchy cassava root flour. Tapioca is an essentially flavourless starchy ingredient, or fecula, produced from treated and dried cassava (manioc) root and used in cooking. It is similar to sago and is commonly used to make a milky pudding similar to rice pudding. Cassava flour, also called tapioca flour or tapioca starch, can also replace wheat flour, and is so-used by some people with wheat allergies such as coeliac disease. Boba tapioca pearls are made from cassava root. It is also used in cereals for which several tribes in South America have used it extensively.

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 are 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.

Ethnomedical uses

  • The bitter variety of Manihot root is used to treat diarrhea and malaria.
  • The leaves are used to treat hypertension, headache, and pain.
  • Cubans commonly use cassava to treat irritable bowel syndrome, the paste is eaten in excess during treatment.

Bermuda

Cassava pie is a traditional Christmas dish. The cassava is peeled and chopped finely, then mixed with egg, butter and sugar. It is layered in a baking dish in alternate layers with chicken or pork. It is then baked in the oven, and leftovers may be fried. It is eaten as a savoury dish, either on the side or as a main meal.

Brazil

Cassava is heavily featured in the cuisine of Brazil. The dish vaca atolada ("mud-stranded cow") is a meat and cassava stew, cooked until the root has turned into a paste; and pirão is a thick gravy-like gruel prepared by cooking fish bits (such as heads and bones) with cassava flour, or farinha. In the guise of farofa (lightly roasted flour), cassava combines with rice and beans to make the basic meal of the (poor) average Brazilians. Farofa is also one of the most common side dishes to many Brazilian foods including feijoada, the famous meat-and-beans stew. Boiled cassava is also made into a popular sweet pudding. Deep-fried (after boiling), it is often eaten as a snack or side dishes.

Bolivia

Cassava is very popular in Bolivia with the name of yuca and consumed in a variety of dishes. It is common, after boiling it, to fry it with oil and eat it with a special hot sauce known as llajwa or along with cheese and choclo (dried corn). In warm and rural areas, yuca is used as a substitute of bread in everyday meals. The capacity of cassava to be stored for a long time makes it suitable as an ideal and cheap reserve of nutrients. Recently, more restaurants, hotels and common people are including cassava into their original recipes and everyday meals as a substitute for potato and bread.

Colombia

In Colombia, cassava is widely known as yuca among its people. In the Colombian interior, it is used mainly in the preparation of Sancocho (a kind of rich soup) and other soups. In the Valle department it is famous, the Pandebono bread made of the yuca dough.

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.

Costa Rica

In Costa Rica, yuca is widely used, both boiled in soups or fried and served with fried pieces of pork and lime. This is sold as a snack in most places you travel. When travelling by bus, the bus is often boarded by a local, trying to sell "sandwich bagged" snacks of yuca, pork and lime. Two main sources of food for locals in rural areas, living off resources within their own land, are yuca and plantain.

Panama

In Panama, yuca is sometimes used to make carimanolas. The boiled cassava is mashed into a dough and then filled with spiced meat. The meat-filled dumplings are deep fried to a golden brown. It is also used in brothy soups together with chicken, potatoes, and other vegetables.

Dominican Republic

Cassava bread (casabe) is an often used complement in meals, much in the same way as wheat bread is used in Spanish, French and Italian lunches. Also, as an alternative to side-dishes like french fries, arepitas de yuca are consumed, which are deep-fried buttered lumps of shredded cassava. Bollitos, similar to the Colombian ones are also made. The root, in its boiled and peeled form, is also present in the typical Dominican 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). Also, a type of empanada called catibía has its dough made out of cassava flour.

Jamaica

In Jamaica, cassava is traditionally made into "bammy," a small fried cassava cake inherited from the native Arawak Indians. The cassava root is grated, rinsed well, dried, salted, and pressed to form flat cakes about 4 inches in diameter and 1/2-inch thick. The cakes are lightly fried, then dipped in coconut milk and fried again. Bammies are usually served as a starchy side dish with breakfast, with fish dishes or alone as a snack.

Eastern Caribbean

In the small islands of the Eastern Caribbean, cassava is traditionally peeled and boiled and served with flour dumplings and other root vegetables like potatoes, yams, sweet potatoes and dasheen.

Venezuela

As in the Dominican Republic, Cassava bread (casabe) is also a popular complement in traditional meals, as common as the arepas. Venezuelan Casabe is made by roasting ground cassava spread out as meter wide pancake over a hot surface (plancha). The result has the consistency of a cracker, and is broken in small pieces for consumption. There is also a sweet variety, called Naiboa, made as a sandwich of two casabe pancakes with a spread of Papelón in between. Naiboa also has a softer consistency. In general terms, Mandioc is an essential ingredient in Venezuelan food, and can be found stewed, roasted or fried as sides or complements.

Peru

Cassava is also popular in Peru by the name of yuca, where it is used both boiled and fried. Boiled yuca is usually served as a side dish or in soup, while fried yuca is usually served together with onions and peppers as an apperitif or accompanying chicha.

Paraguay

Cassava is a staple dish of Paraguay. It grows extremely well in the soil conditions throughout the country, and it is eaten at practically every meal. It is generally boiled and served as a side dish. It is also ground into a flour and used to make chipa, a bagel-shaped bread popular during holidays.

Countries in Africa

 
Woman pounding the cassava root into fufu in the Central African Republic.

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 then cooked further or stored. A popular snack is made by marinating cassava in salted water for a few days then grilling it in small portions. Many cassava dishes exist in various African countries.

In Tanzania, cassava is known as mihogo, plural form, in Swahili. Though customs vary from region to region, and the methods of cooking cassava vary accordingly, the main method is simply frying it. The skin of the root is removed and the remains are sectioned into small bit-size chunks which 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. The staple of the rural people, ugali, is a porridge more akin to mashed potatoes in consistency. In Zambia this is known as nshima. In Kenya, the Kikuyu name for it is mwanga, pl mianga.

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. 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 plant leaf is also soaked and boiled for extended periods of time to remove toxins and then eaten. The taste is similar to spinach. In the local language Sango, this is called gozo. U.S. Peace Corps Volunteers stationed in the Central African Republic refer to the cassava plant as the multi-purpose staple.

India

 
Boiled casava served with fish and chutney

In the state of Kerala, India, cassava is a secondary staple food. Boiled casava is normally eaten with fish curry (kappayum meenum in Malayalam) or meat, and is a traditional favorite of many Keralians. 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. Cassava is widely cultivated and eaten as a staple food in Andhra Pradesh. The household name for processed cassava is sabu dana or saggu biyyam.

Indonesia

Cassava is widely eaten in Indonesia, and used as a staple food during hard times but has lower status than rice. It is boiled or fried (after steaming), baked under hot coals, or added to kolak dessert. It is also fermented to make peuyeum and tape, a sweet paste which can be mixed with sugar and made into a drink, the alcoholic (and green) es tape. It is available as an alternative to potato crisps. Gaplek, a dried form of cassava, is an important source of calories in the off-season in the limestone hills of southern Java. Their young leaves also eaten as gulai daun singkong (cassava leaves in coconut milk), urap (javanese salad) and as main ingredient in buntil (javanese vegetable rolls).

Animal feed

Cassava is used as animal feed extensively in Asia, South America, Africa, and Europe. Especially in places such as Thailand, China, Nigeria, Brazil, etc.

Cassava hay

Cassava hay, is hay which is produced at a young growth stage, 3-4 months and being harvested about 30-45 cm above ground, sun-dried for 1-2 days until having final dry matter of at least 85%. The cassava hay contains high protein content, 20-27% CP and condensed tannins, 1.5-4%. It is used as a good roughage source for dairy, beef, buffalo, goats, sheep by either directing feeding or as a protein source in the concentrate mixtures. More details can be searched from Metha Wanapat AJAS,Asian-Australasian Journal of Animal Sciences.

Cassava pests

Main article: List of cassava diseases

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. 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 Congo. [2]

References

  1. Claude Fauquet and Denis Fargette, (1990) "African Cassava Mosaic Virus: Etiology, Epidemiology, and Control" Plant Disease Vol. 74(6): 404-11. [1]
  2. [*University of Colorado at Boulder, (2007) "CU-Boulder Archaeology Team Discovers First Ancient Manioc Fields In Americas", press release August 20, 2007, accessed August 29, 2007.
  3. Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
  4. Aregheore E. M, Agunbiade O. O. (1991). "The toxic effects of cassava (manihot esculenta grantz) diets on humans: a review.". Vet. Hum. Toxicol. 33: 274-275. 
  5. White W. L. B., Arias-Garzon D. I., McMahon J. M., Sayre R. T. (1998). "Cyanogenesis in Cassava, The Role of Hydroxynitrile Lyase in Root Cyanide Production". Plant Physiol. 116: 1219-1225. 
  6. J. Howard Bradbury (2006). "Simple wetting method to reduce cyanogen content of cassava flour". Journal of food composition and analysis (Elsevier, New York) 19 (4): 388-393. doi:10.1016/j.jfca.2005.04.012. 
  7. Template:Cite press release
  8. G. Padmaja (1995). "Cyanide detoxification in cassava for food and feed uses.". Crit. Rev. Food Sci. Nutr.: 299-339. 

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