The cassava, cassada, yuca, manioc, mogo or mandioca (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 the third largest source of carbohydrates for human food in the world, with Africa its largest center of production.
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.
The leaves cannot be consumed raw because 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.