A study of the role of tissue disruption in the removal of cyanogens during cassava root processing

Sun-drying as a means to reduce the cyanogen content of cassava roots is commonly known to be inefficient. This paper reports on modifications to the processing procedure used for sun-drying and their effectiveness at removing potentially toxic cyanogenic glucosides. Commonly used processing methods were compared. Crushing cassava root pieces prior to drying was found to significantly improve the efficiency of cyanogen removal by, on average, 22% during laboratory experiments and 12% during field trials. The crushing procedure was optimized and a low cost prototype crusher developed. A reduction in the processing time resulted from crushing the root disks prior to drying. The processing method involving crushing was ranked second in terms of efficiency of cyanogen removal in a comparative study of sun-dry processing methods that are commonly used in East Africa. Pounding cassava to small pieces in a traditional pestle and mortar prior to drying was the most efficient, providing 90% removal of cyanogens. Pounding and crushing cassava prior to sun-drying were significantly better than all other root preparation pre-treatments evaluated.