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

타피오카와 겉보리 혼합원료의 당화 및 알코올 발효의 특성 연구

Abstract

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% ${\alpha}-amylase$ "Spezyme-Fred" and saccharified using an enzyme mixture (GPB), which consisted of glucoamylase (G), protease (P), and ${\beta}-glucanase$ (B). After the TB mixture (7:3, w/w) saccharified for 150 min at $50^{\circ}C$, 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 ${\beta}-glucanase$ 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 $30^{\circ}C$. 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.

알코올 발효에 이용되는 타피오카와 겉보리 혼합원료의 효소당화액을 제조하여 알코올 발효 특성을 조사하였다. 타피오카와 겉보리 혼합원료를 내열성 액화효소인 Spezyme Fred를 0.04% 사용하여 액화하고 글루코아밀레이스(G), 단백질가수분해효소(P), 베타글루칸 가수분해효소(B)를 혼합한 당화효소제(GPB)를 사용하여 당화하였다. 타피오카와 겉보리 혼합원료(7:3, w/w)를 $50^{\circ}C$에서 150분간 당화하였을 때 당화액의 포도당 함량은 11.9%였고 점도는 26 cp로 나타났다. 베타글루칸 가수분해효소(B)의 첨가는 당화액의 포도당 수율의 증가와 점성의 저하에 도움을 주었다. 타피오카와 겉보리의 혼합비율을 7:3(w/w)으로 하였을 때 다른 비율의 당화액에 비하여 점도가 낮으며 포도당 함량이 높게 나타났다. 타피오카와 겉보리 혼합원료에 300%의 가수량으로 확립된 조건에서 당화하고 $30^{\circ}C$에서 72시간 알코올 발효를 수행한 결과 타피오카와 겉보리 혼합원료를 이용한 알코올 발효에 적합한 발효액의 알코올 및 포도당 함량은 각각 9.0과 0.02%였고, pH와 산도는 각각 pH 4.3과 0.3%이었다.

Fig. 1. Effect of temperature on viscosity and glucose content after saccharification of tapioca and hulled barley mixture (7:3, w/w) for 180 min by adding 0.3% saccharogenic enzyme (GPB). □: Viscosity, ■: Glucose content

Fig. 2. Effect of time on viscosity and glucose content after saccharification of tapioca and hulled barley mixture (7:3, w/w) at 50^oC by adding 0.3% saccharogenic enzyme (GPB). ■:Viscosity, ●: Glucose content

Fig. 3. Effect of enzyme (glucoamylse: G, protease: P, β-glucanase: B, hemicellulase: H) combination on viscosity and glucose content after saccharification of tapioca and hulled barley mixture (7:3, w/w) at 50oC for 150 min. □: Viscosity, ■:Glucose content

Fig. 4. Effect of raw material composition of tapioca and hulled barley mixture on viscosity and glucose content after saccharification at 50^oC for 150 min by adding 0.3% saccharogenic enzyme (GPB). □: Viscosity, ■: Glucose content

Fig. 5. Effect of added water content on alcohol content and glucose content after alcohol fermentation of saccharified liquid at 30^oC for 60 h. Saccharification of tapioca and hulled barley mixture (7:3, w/w) was carried out for 150 min at 50^oC by adding 0.3% saccharogenic enzyme (GPB). ■: Glucose content,●: Alcohol

Fig. 6. Effect of added water content on total acidity and pH content after alcohol fermentation of saccharified liquid at 30^oC for 60 h. Saccharification of tapioca and hulled barley mixture (7:3, w/w) was carried out for 150 min at 50^oC by adding 0.3% saccharogenic enzyme (GPB). □: pH, ■: total acidity

Fig. 7. Effect of saccharogenic enzyme concentration on alcohol content and glucose content after alcohol fermentation of saccharified liquid at 30^oC for 60 h. Saccharification of tapioca and hulled barley mixture (7:3, w/w) was carried out for 150 min at 50^oC by adding saccharogenic enzyme (GPB) of different concentration. ■: Glucose content, ●: Alcohol

Fig. 8. Effect of saccharogenic enzyme concentration on pH and total acidity after alcohol fermentation of saccharified liquid at 30^oC for 60 h. Saccharification of tapioca and hulled barleymixture (7:3, w/w) was carried out for 150 min at 50^oC byadding saccharogenic enzyme (GPB) of different concentration. □: pH, ■: total acidity

Fig. 9. Time course of alcohol fermentation of saccharified liquid at 30^oC for 60 h. Saccharification of tapioca and hulled barley mixture (7:3, w/w) was carried out for 150 min at 50^oC by adding saccharogenic enzyme (GPB) of different concentration. ■: Glucose content, ●: Alcohol

Fig. 10. Changes in pH and total acidity during alcohol fermentation at 30^oC for 60 h. Saccharification of tapioca and hulled barley mixture (7:3, w/w) was carried out for 150 min at 50^oC by adding saccharogenic enzyme (GPB) of different concentration. □: pH, ■: Total acidity

Table 1. β-Glucan content of raw material