논문 상세보기
pp.151-156
본 연구는 쌀을 다량 첨가하여 양조한 맥주의 품질개선을 위하여 아밀라아제, 프로테아제, 쌀에 결핍된 아미노산의 첨가를 시도하여 그 품질 개선의 효과를 분석하였다. 품질 요소는 당화액인 wort의 당도, 환원당, pH, 점도의 변화를 측정하였고, 최종 제품인 맥주의 알코올 함량, 거품 안정성, 쓴맛, 색도의 변화를 측정하였다. 실험에는 200 mesh의 쌀가루를 맥아와 쌀가루의 총량에 대하여 0, 40, 50, 60, 70%를 첨가하였다. 실험 결과 쌀 함량이 증가함에 따라 wort의 당도, 환원당 및 점도는 감소하였고, pH는 증가하여 당화력이 떨어졌다. 그러나 아밀라아제 첨가에 의하여 당화력이 다시 회복되었기 때문에 아밀라아제 첨가로 쌀맥주 제조 및 제품의 성능이 향상되는 결과를 보였다. 쌀 함량 증가에 따라 맥주의 알코올 함량 및 거품 안정성은 감소하였고, 쓴맛과 노란색이 증가하였다. 그러나 프로테아제 첨가에 의하여 알코올 함량, 쓴맛 및 노란색은 다시 회복되었으나 거품 안정성은 더욱 감소하였다. 글루타민산의 첨가에 의하여 노란색 외의 성질은 모두 회복되었다. 그러나 라이신 및 프롤린의 첨가에 의하여 알코올 함량 및 쓴맛은 회복되었으나 거품 안전성이 낮아지고, 색이 비정상적으로 탁하게 나타났다. 결과적으로 쌀 첨가 맥주의 품질향상 인자는 아밀라아제의 첨가, 글루타민산의 첨가, 프로테아제의 첨가의 순으로 결정되었다.
Various enzymes and amino acids were used to improve the quality attributes of beer brewed with rice adjunct. Alpha-amylase was applied to make more saccharification during the malting stage. Protease and amino acids, such as lysine, glutamic acid, and proline, were added prior to fermentation stage and the qualities of beer such as Brix, reducing sugar content, pH, and viscosity of the wort, were evaluated. The changes in the alcohol content, bubble stability, bitterness, and color of the beer were also investigated. Results showed that Brix, reducing sugar content, and viscosity of the wort were reduced, while the pH was increased in proportion to the rice powder content. It revealed that the liquefaction rate was decreased as the content of rice powder was increased. But the liquefaction rate was recovered by the addition of α-amylase. The alcohol content and bubble stability of beer were decreased while its bitterness and yellowness were increased in proportion to the rice powder content. While alcohol content, bitterness, and yellowness were recovered by the addition of protease, the bubble stability was reduced in spite of the use of protease. Other characteristics of the beer except yellowness color were recovered by the addition of glutamic acid. However, when lysine and proline were used, alcohol content and bitterness were recovered. The bubble stability and the turbidity of the beer were not improved although the amino acids were used. The rice beer quality was thus improved by the addition of amylase, followed by glutamic acid and protease.
