Making cassava safer for consumers
MetadataShow full item record
CTA. 1995. Making cassava safer for consumers. Spore 60. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47197
After rice and maize, cassava is the third most important crop in the tropics. It is a staple for 500 million people in rural Africa, Asia and South America, but can be extremely toxic. In the last 10 years in Zaire and Mozambique alone, 10,()(10...
After rice and maize, cassava is the third most important crop in the tropics. It is a staple for 500 million people in rural Africa, Asia and South America, but can be extremely toxic. In the last 10 years in Zaire and Mozambique alone, 10,()(10 women and children have been poisoned by cassava. Cassava tubers contain high levels of cyanoglucoside, as well as the enzymes which break-down this poison. When the enzymes come into contact with the cyanoglucoside, the process of breaking-down the poison releases hydrogen cyanide gas (HCN). If the root is eaten without processing it to remove all the cyanoglucoside, then chronic cyanide poisoning, and even paralysis, may result. In order to render the cassava harmless, it has to be processed using one of over 180 different processing techniques. The most common processing method is fermentation which removes the barriers between the cyanoglucoside and the enzymes, allowing the enzymes to break down the poison, but this method can not be relied upon to remove all the poison. Researchers at the University of Newcastle in England have cloned the genes for these two enzymes. 'Cloning the genes is the first step in manipulating the chemistry of the plant to make it safer to eat' said Professor Monica Hughes, a biochemist on the Newcastle team. She went on to say that they will use the cloned genes to improve the fermentation process. Inserting the genes into bacteria normally used in the fermentation plants of Africa will produce a strain of bacteria which manufactures the cyanoglucoside-destroying enzymes, increasing the efficiency of the fermentation process. This genetically engineered bacterium, once distributed, will then be self-sustaining. For the future, the team is looking at the possibility of using the cloned genes to increase the levels of the enzymes in the cassava tuber, increasing the efficiency not only of the fermentation process, but of any cassava treatment which breaks down the barriers between the enzymes and the poison. Professor Monica Hughes Department of Biochemistry and Genetics The Medical School University of Newcastle Framlington Place Newcastle-on-Tyne NE2 4HH UK