CYANOGEN REMOVAL FROM CASSAVA ROOTS DURING SUN-DRYING

Linamarin levels in sun-drying cassava root pieces showed an exponenti al decrease, parallel with the moisture loss, and stabilized when mois ture levels reached about 15%. Linamarin degradation in thin root segm ents was significantly slower and less complete than in thick ones. Di sinfected longitudinal root halves, oven-dried at 40 degrees C for 24 h, had significantly higher residual linamarin levels than the matched ones subjected to humid incubation at 25 degrees C. Interrupting for one or two days the sun-drying of peeled roots resulted in significant ly lower residual levels of linamarin and of cyanohydrins plus HCN. Li namarin degradation was greater when the interruption was earlier or l onger. The rate of dehydration influences linamarin degradation negati vely - mechanisms are discussed. Cyanohydrin removal was completed by prolonged drying. Sun-drying is not very effective in linamarin remova l, and speeding up the drying process, e.g. by reducing the size of th e pieces, aggravates this. There is a potential for increasing the eff ectiveness of cyanogen removal by reducing the initial drying rate, fo llowed by thorough final drying. (C) 1996 Elsevier Science Ltd.