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U.S. Department of Health and Human Services

FDA Poisonous Plant Database

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AUTHOR(S): Coursey, D. G.
TITLE: Cassava as food: Toxicity and technology.
YEAR: 1973 CITATION: Nestel B, MacIntyre R (eds.) Chronic cassava toxicity. Intnatl Dev Res Ctr. Ottawa. IDRC-010e, -(), 27-34 [English]
FDA #: F20143
ABSTRACT: Abstract: The toxicity of cassava (Manihot spp.) is caused by the presence of the cyanogenic glycoside linamarin, together with much smaller amounts of the closely related lotaustralin. These substances hydrolyse under the influence of the endogenous enzyme linamarase to liberate hydrogen cyanide (HCN). The quantities of toxic principle vary greatly between cultivars and, although the so-called "sweet' cultivars are generally of lower toxicity than the 'bitter' ones, the correlation is not exact. Cyanide levels cannot be related to formal botanical taxa. Some variation in cyanogen content with ecological conditions of plant growth also occurs. A wide variety of traditional food preparations techniques are used for processing cassava in different parts of the world and an important element in all of these is an attempt to reduce the cyanide content by liberation of the HCN either by solution in water or by volatilisation. These processes involve maceration, soaking, boiling, roasting, or fermentation of the cassava roots, or a combination of these processes. The amount of analytical data available on the efficacy of these processes is limited and generally unreliable. It appears that normally the greater part of the cyanide is liberated in such processes, but there are often substantial residual quantities which may well be sufficient to produce chronic toxic symptoms, and occasionally even acute poisoning, in those who consume large quantities of cassava products. Little reliable information is available as to whether linamarin itself constitutes a toxic factor, or whether toxicity only arises from hydrolysis of this compound to free cyanide.
GRIN #: 431678 Exit Disclaimer
COMMON NAME: cassava
STANDARD PLANT NAMEManihot esculenta Crantz