Hydrolysis kinetic of suweg (Amorphophalluscampanulatus B) starch using a mixture of alpha amylase and glucoamylase

Abstract

Hydrolysis kinetic of Suweg (Amorphophalluscampanulatus) starch using a mixture of two enzymes have been investigated. This research was carried out on Suweg starch at a concentration 200 gL-1 using a mixture of alpha amylase and glucoamylase at concentration 1.5% (w/w) and ratio 1:1 at pH 4.5 and temperature 60-90°C for 12 hours. The optimum condition of the process was hydrolysis at temperature 70°C for 9 hours, which resulted reducing sugar concentration of 105.919 gL-1. Constant of reaction rate (k) is calculated from relation between - ln (CA/CA0) versus time, while the activation energy is calculated using the Arrhenius equation. The constant of reaction rate at temperature 60°C, 70°C, 80°C, 90°C were 0.2969 h-1, 0.4433 h-1, 0.3932 h-1, 0.3464 h-1, respectively. It was found that the activation energy was 18989.176 Jmol-1. The result shows that using a mixture of alpha amylase and glucoamylase can reduce heat requirement in conventional hydrolysis.