Saccharification and alcohol fermentation characteristics of a mixture of tapioca and hulled barley

An enzymatically saccharified tapioca and hulled barley (TB) raw mixed solution was used to examine alcohol fermentation characteristics. The TB mixture was liquefied with 0.04% α-amylase “Spezyme-Fred” and saccharified using an enzyme mixture (GPB), which consisted of glucoamylase (G), protease (P), and β-glucanase (B). After the TB mixture (7:3, w/w) saccharified for 150 min at 50 ^o C, its glucose content was 12.9% and viscosity was 26 cp. The use of GPB for the saccharification of TB was appropriate because the addition of β-glucanase increases the glucose yield and decreases the viscosity of the saccharification liquid. The TB ratio was optimized to 7:3 (w/w) on the basis of the lower viscosity and the higher glucose content after saccharification. After TB mixture with 300% (w/w) water content was better condition than others for alcohol fermentation when it was carried out at 30 ^o C. The alcohol and glucose contents of the TB mixture fermented for 72 h were 9.0 and 0.02%, respectively, and the pH and total acidity were 4.3 and 0.3%, respectively.