OPTIMIZATION OF ENZYMATIC HYDROLYSIS OF CASSAVA (MANIHOT ESCULENTA) STARCH CONTAINING CYANIDES

Abstract

The bitter cassava plant (Manihot esculenta), commonly referred to as bitter cassava, is a wild species that thrives in forests and gardens. The tubers of bitter cassava contain cyanogenic compounds, which are toxic due to the presence of cyanide. Cyanide removal can be achieved through extraction using water or heating at a temperature of 50 ºC. Bitter cassava starch can be converted into reducing sugars through enzymatic processes. In this study, experiments were conducted using bitter cassava starch at concentrations of 100, 200, and 300 g L^-1 (native), with added cyanide concentrations of 50, 100, and 150 mg kg^-1 as inhibitors. The effects of these variables on reducing sugar production were analysed through enzymatic hydrolysis at 30ºC. The optimization of enzymatic hydrolysis in the presence of cyanide was performed using Response Surface Methodology (RSM). The study investigated the effects of starch concentration, cyanide concentration, and hydrolysis time on reducing sugar production. RSM has been proven to be an effective and reliable tool for optimizing the process and understanding the interactive effects of the three variables involved in cassava starch hydrolysis. A highly significant quadratic regression model (R² = 0.9900, P < 0.0001) was developed. The predicted optimal conditions for hydrolysis were identified as 278.5 g L^-1 starch concentration, 51.4 mg kg^-1 cyanide concentration, and a hydrolysis time of 14.8 h, resulting in a reducing sugar concentration of 63.498 g L^-1.