Resumo

QUINONEZ, Rafael et al. Effect of different types of root and leaf dehydration of bitter cassava (Manihot esculenta) on its chemical composition. Zootecnia Trop. [online]. 2007, vol.25, n.1, pp.43-49. ISSN 0798-7269.

The aim of this study was to determine the impact of the type of drying treatment of  roots and leaves of bitter cassava (Manihot esculenta), on its chemical composition. The treatments were:  T1:  yard drying (PS); T2:  drying on room with glass roof (CS); T3: Stove (E) and T4: on drying tunnel (TS). Chemical analyses and  hydrocyanic acid (HCN, free and total) concentration were determined. In the roots, MS, the total quantity of starch and of sugars reducers were not affected (P>0.05); while the percentage of total sugars increased with the drying temperature in TS and E (8.56 and 7.29, respectively), with differences (P<0.01) in CS and PS (5.43 and 5.72, respectively). The determination of MS, PC, and FND in the leaves did not show differences. The concentration of total HCN decreased from 132.73 ppm in fresh roots to 98.01 86.44 76.09, and 63,63 ppm for PS, CS, E, and TS, respectively. In the leaves the concentration diminished from 135.59 ppm to 65.19 ppm (PS); 54.06 ppm (CS), 45.17 ppm (E), and 31.32 ppm (TS). It is concluded that high temperatures and fast dehydration are excellent to lower the concentration of HCN for roots and leaves. However, some deterioration of the quality of the root occur due to the increment in the quantity of total sugars.

Palavras-chave : Bitter cassava; chemical composition; HCN; types of dehydrated.