|Cassava- (Manihot esculenta), is also called manioc, yuca, balinghoy or kamoteng kahoy (in the Philippines), mogo (in Africa), mandioca, tapioca-root (predominantly in India) and manioc root, a woody shrub of the Euphorbiaceae (spurge) family native to South America, is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates. It differs from the similarly spelled yucca, an unrelated fruit-bearing shrub in the Asparagaceae family. Cassava, when dried to a powdery (or pearly) extract, is called tapioca; its fermented, flaky version is named garri.
Cassava is the third largest source of food carbohydrates in the tropics, after rice and maize. Cassava is a major staple food in the developing world, providing a basic diet for over half a billion people. It is one of the most drought tolerant crops, capable of growing on marginal soils. Nigeria is the world's largest producer of cassava, while Thailand is the largest exporting country of dried cassava.
Cassava root is a good source of carbohydrates, but a poor source of protein. A diet consisting predominantly of cassava root can cause protein-energy malnutrition.
Cassava is classified as sweet or bitter. Like other roots and tubers, cassava contains antinutritional factors and toxins. It must be properly prepared before consumption. Improper preparation of cassava can leave enough residual cyanide to cause acute cyanide intoxication and goiters, and may even cause ataxia or partial paralysis. Nevertheless, farmers often prefer the bitter varieties because they deter pests, animals, and thieves. The more toxic varieties of cassava are a fall-back resource (a "food security crop") in times of famine in some places
The cassava root is long and tapered, with a firm; homogeneous flesh encased in a detachable rind, about 1mm thick, rough and brown on the outside. Commercial varieties can be 5 to 10 cm in diameter at the top, and around 15 cm to 30 cm long. A woody cordon runs along the root's axis. The flesh can be chalk-white or yellowish. 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 (rich in lysine) but deficient in the amino acid methionine and possibly tryptophan.