Enzymatic hydrolysis of bitter cassava and Gadung starches with different compositions at low temperature

Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Jl. Prof. Soedarto, SH, Tembalang, Semarang 50275, Indonesia, Telp./Fax.: +62247460058 / +622476480675

^* Corresponding author: hargono@che.undip.ac.id

Abstract

The effect of compositions of bitter cassava (Manihot glaziovii) and gadung (Dioscorea hispida Dennst) starches on reducing sugar during hydrolysis using granular starch hydrolyzing enzyme (GSHE) was studied. All hydrolyses were conducted at concentration of substrate was 200 g.L^-1, while concentration of enzyme was 1.5 % (w/w), during of hydrolysis time 24 h, at 30°C. Mass compositition of bitter cassava and gadung starches were 9:1 to 1:9 The increase gadung starch compositions will decrease the reducing sugar. The optimum condition of the process using concentration of substrate 200 g.L-1 with compositions of bitter cassava and gadung starches was 9:1 at 18 h. It was found that reducing sugar was 50.20 g.L^-1. The concentration of reducing sugar mainly depend on starch content on bitter cassava, it is much bigger than the gadung starch.