Journal of Microbial & Biochemical Technology

Abstract

Effect of Carbon Dioxide Injection on Physiochemical Properties and Saccharification of Extruded Corn Starch for Fermentation Substrate Preparation

Lin Myat and Gi-Hyung Ryu

The objective of this research was to investigate the effect of carbon dioxide injection during extrusion process at different melt temperatures 95, 115 and 135°C on physiochemical properties and enzymatic saccharification of extruded corn starch for fermentation substrate preparation. Carbon dioxide gas was injected during extrusion at the flow rate of 500 ml/min and pressure of 3 MPa. For enzymatic saccharification, 0.8% α-amylase enzyme was used at different saccharification periods. After extrusion, physiochemical properties and reducing sugar content were measured. Carbon dioxide injection had positive effects on breaking strength, elastic modulus, expansion ratio, specific length, piece density, water absorption index, water solubility index, free amino nitrogen and reducing sugar content (after saccharification) at melt temperatures 115 and 135°C. However, significant decrease (p<0.05) in specific mechanical energy input was obtained at only 135°C. The data clearly showed that carbon dioxide injection gave significantly increased (p<0.05) reducing sugar content at melt temperatures 115 and 135°C for fermentation substrate preparation.