The effect of substrate and enzyme concentration on the glucose syrup production from red sorghum starch by enzymatic hydrolysis

Red sorghum starch contains 19% amylose and 34% amylopectin but low gluten, therefore, it is not suitable for bakery production. On the other hand, red sorghum is potential for glucose syrup production. Glucose syrup can be produced by enzymatic hydrolysis from starch by liquefaction process with α-amylase and saccharification process with glucoamylase. Enzyme concentration plays an important role in the yield of hydrolysis process. This experiment aimed to produced glucose syrup from red sorghum starch by hydrolysis enzymatic method. Liquid α-amylase and glucoamylase were applied for red sorghum starch with particle size 125 μm. Concentrations of α-amylase and glucoamylase were 0.2 and 0.27% (v/v), respectively. Substrate concentration was varied at 10, 20, 30, and 40% (w/v) for each 300 ml substrate solution. Liquefaction process was carried out at 90°C for 60 min whereas saccharification process was carried out at 60°C for 120 min with constant pH 6 for each process. The substrate was then strained as the hydrolysate. The hydrolysate was analyzed for its reducing sugar content by dinitrosalicylic acid (DNS) reagent. The glucose concentration was analyzed by HPLC. The highest reducing sugar concentration was 191.60 g/l, 17.44% glucose observed for 40% substrate and 0.27% enzyme concentration, respectively.