The effect of reducing cyanide level in bitter cassava (Manihot Esculenta Crantz) on the starch content

Bitter cassava (Manihot Esculenta Crantz) is often seen as a ‘dangerous toxic crop’ due to its high cyanide level (>100 mg/kg). The reduction of cyanide level on this type of cassava is usually conducted with soaking the tubers and drying the starch. However, the effect of these methods on the starch level hasn’t been investigated. On this work, the effect of soaking time and drying temperature at the elimination of cyanide content of bitter cassava to the starch content were analyzed. The cyanide in cassava was reduced through soaking (24 h, 48 h, 72h, and 96 h) and drying (room temperature, 30oC, 45oC, 60oC, 75oC). The cyanide content was determined through the Bradbury method and the intensity of the cyanide (CN) functional group with the Fourier Transform Infrared Spectroscopy (FTIR). The result shows, the highest cyanide elimination was observed in the soaking treatment of 96 h (85%) meanwhile the highest starch content was examined at the soaking treatment of 24 h (84.3%). The transmission intensity between fresh bitter cassava and starch was significantly reduced. Groups of cyanide were detected in the cassava tuber between 2077 cm−1 and 2103 cm−1. After the tubers were transformed into starch through soaking and drying, cyanide was significantly decreased. Soaking cassava tubers in water was the most effective method for reducing cyanide while maintaining high starch content. The results of the analysis of variance showed that the difference between soaking and drying treatment was significantly different, but it doesn’t affect amylose and amylopectin levels in the cassava starch it is shown from F value (37.43) > F table (6.09).