Cassava
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.
Cassava is called mandioca, aipim, or macaxeira in Portuguese, mandio in Guaraní, maniok in Afrikaans and Rotuman, yuca or mandioca in Spanish, muhogo in Swahili,mogho in Gujarati, tapioka in Fijian, kappa or maracheeni in Malayalam, singkong or ubi kayu in Indonesian and Malay language, tugi in Ilocano, balinghoy in Tagalog, maniok in German, Danish and Czech, manyok in Haitian Creole, lumu in Kichwa, manioc in French, mannyokka in Sinhala, khoai mì, khoai sắn in Vietnamese, mianga in Kikuyu, muwogo in Luganda, and cassave in Dutch.
History and economic impact
The s
pecies Manihot esculenta originated in South America. It was domesticated before recorded history in Brazil and Paraguay, became the staple food of the native populations of northern South America and the West Indies and was later assimilated by the Portuguese and Spanish. Forms of the modern domesticated species can be found growing spontaneously 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.
Farming
assava 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 harvestProcessing
he 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. [1] [2] 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.[3] This method is currently being promoted in rural African communities that are dependent on cassava.[4]
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.[5] The flour is used throughout the Caribbean.
