Change in free cyanide content of bitter cassava during incubation and drying and physical properties of dry-milled cassava flour

Abstract

Cassava root contains cyanogenic glycosides that can undergo cyanogenesis and produce cyanide, which is hazardous to human health. Cassava starch is produced by wet-milling cassava, a good method for eliminating cyanogens. Nonetheless, the operation consumes considerable water and generates highly organic and acidic wastewater. For a more sustainable technique, dry milling can be used to conserve water and reduce waste. An alternative method for removing cyanogen must be investigated. This study aimed to determine the effect of incubation and drying temperatures on the concentration of free cyanide in cassava flour. Incubation for four hours increased the amount of free cyanide in fresh cassava cubes, which decreased thereafter. A 24-hour incubation lowered free cyanide by 30.5–53.7%. During the initial forty minutes of drying at varied temperatures (60, 70, and 80 °C), the free cyanide concentration increased dramatically before decreasing. Drying for four hours caused 53.6–78.5% reduction in HCN from the initial concentration before drying. The reduction rate and concentration of free cyanide in dry-milled cassava flour were not significantly changed by drying at different temperatures. Dry processing allows 70–90% reduction in water requirement.