Factors affecting cyanide content in cassava (Manihot esculenta Crantz) [Faktor yang mempengaruhi kandungan sianida dalam ubi kayu (Manihot esculenta Crantz)]

Concern over poisoning as a result of eating cassava roots or shoots has led to these studies to determine factors which lead to high cyanide content in these tissues and how detoxification can be carried out. Plant age or stage of development does not seem to have a clear influence on root or shoot cyanide content. Genetic control on cyanide content seems significant as varieties may be identified according to low or high cyanide contents in their shoots or roots. A low cyanide content in the root flesh is no guarantee of 'safe' cyanide levels in the shoots or leaves. Drought tends to increase cyanide content in edible cassava varieties. The traditional method of preparing ulam from cassava shoots by blanching is effective in removing only part of the cyanide present. Modifications to the method (chopping and soaking the shoots before blanching) can reduce the cyanide level further. *Division of Horticulture, Headquarters Station, MARDI Serdang, P.O. Box 12301, 50774 Kuala Lumpur, Malaysia Author’s full name: Tan Swee Lian ©Malaysian Agricultural Research and Development Institute 1996 Introduction In common with a few other crop species, cassava (Manihot esculenta Crantz) produces cyanide in a bound form (cyanogenic glucoside) which is found in all its plant tissues (Nambisan 1992). Free cyanide or HCN, a highly volatile and soluble substance, is released when cell walls are broken down by injury (due to pest damage or mechanical means), thereby liberating the enzyme linamarase which acts on the bound cyanide.