Cassava roots are very starchy and their protein content is less than that of other tropical root crops such as yam, sweet potato, and taro. Cassava contains the cyanogenic glucoside linamarin and a small amount of lotaustralin (methyl linamarin) both of which are broken down to cyanohydrins and glucose, catalysed by the enzyme linamarase also present in the root. The cyanohydrins readily break down to hydrogen cyanide in neutral or alkaline conditions.
The cassava plant has a large amount of linamarin in the leaves and in the skin of the root. Sweet cassava has a small amount of linamarin in the inner part of the root called the parenchyma and bitter cassava has a much larger amount. The bitter taste is mainly due to linamarin but there are other bitter compounds in the root and also sour constituents, which sometimes confuses the taste buds King and Bradbury, (1995). The total cyanide content of the parenchyma of different cassava varieties ranges from 1 mg HCN equivalents / kg fresh root (1 ppm) to 1550 ppm. In Nigeria one variety is called "chop and die". The parenchyma from sweet cassava is cooked and eaten whereas that from medium and high cyanide cassava must be processed into products such as flour and gari (see Traditional methods of processing cassava roots and leaves). Cassava leaves are used widely in tropical Africa. They are a good source of protein and vitamins but contain large amounts of linamarin that is traditionally removed by pounding followed by boiling in water (see Mild method to remove cyanogens from cassava leaves).
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