Screening of Brewing Yeasts and Saccharifying Molds for Foxtail Millet-Wine Making

In order Nuruk to improve the quality of millet wine, a traditional Jeju cereal wine, yeasts and molds were isolated from 35 kinds of Nuruk collected nationwide. Isolated strains were screened for saccharification of starch and brewing of millet wine. Fermentation characteristics of millet wine with different types of Nuruk were also investigated. The average number of microbial populations in the Nuruk were $6.4{\times}10^5{\sim}4.5{\times}10^7\;cfu/g$ for molds and $1.4{\times}10^4{\sim}7.7{\times}10^7\;cfu/g$ for yeasts. Among the 169 strains of molds and 103 strains of yeasts, 16 strains were screened for saccharifying activity on starch as a substrate, and one yeast strain was screened for the brewing of millet wine. A8-3, supposed as Aspergillus sp., showed the highest enzyme activities of glucdamylase, ${\alpha}-amylase$ and xylanase while B23-3 strain, supposed as Rhizopus sp., showed the highest saccharifying activity. A10-4, supposed as Saccharomyces sp., showed the highest level of weight loss from $CO_2$ evolution, sugar and alcohol tolerance during fermentation. When the Nuruk was made after inoculation with the selected strains, saccharifying activity was higher for the co-cultivation of A8-3 and B23-3 than individual cultivation of each strain. Similar saccharifying activities were shown in both disc-type and pellet-type Nuruk. It was suggested that pellet-type Nuruk could improve fermentation yield. The collected Nuruk consisted of $10{\sim}13%$ moisture, $55{\sim}70%$ total sugar, $10{\sim}18%$ crude protein, $0.2{\sim}1.0%$ crude fat and $1.8{\sim}2.1%$ ash. The Nuruk made in this study was composed of $12{\sim}15%$ moisture, $61{\sim}71%$ total sugar, $15{\sim}20%$ crude protein, $0.4{\sim}1.5%$ crude fat and $1.1{\sim}1.5%$ ash.

제주민속 좁쌀약주 발효를 위한 우수균주의 선발

제주민속주인 좁쌀약주의 주질 개선을 위하여 전국에서 수집된 35종의 누룩으로부터 우수 곰팡이와 효모를 분리하였다. 수집된 누룩의 균수는 1 g당 곰팡이가 $6.4{\times}10^5{\sim}4.5{\times}10^7$개, 효모는 $1.4{\times}10^4{\sim}7.7{\times}10^7$개로 나타났다. 이 중에서 곰팡이 169균주, 효모 103균주를 분리하였으며 전분당화력이 좋은 곰팡이 16균주와 내당성 및 내알로올성이 강한 효모 1균주를 선발하였다. 분리된 곰팡이 균주들의 효소활성을 측정한 결과 A8-3이 glucoamylase활성, 액화력, xylanase 활성이 가장 높았고, B23-3은 당화력이 가장 우수하였다. 우수효모를 선발하기 위하여 pH,무게 감량, 내당성, 내알코올성 등을 측정한 결과, Saccharomyces속으로 추정된 A10-4가 가장 우수하였다. 같은 원료비율로 만든 누룩에 우수균주를 접종하였을 때, 단일 균주를 처리할 때보다 A8-3과 B23-3인 두 균주를 혼합하여 처리한 경우가 당화력이 높게 나타났다. 누룩을 원반형의 누룩과 팰릿(개량형) 형태로 만들어 혼합종균 배양액을 접종한 후 당화력을 측정한 결과, 비슷한 당화력을 나타내었다. 개량형 누룩을 사용하여 양조하는 경우, 좁쌀주 양조에 발효효율을 높일 수 있을 것으로 판단되었다. 수집된 누룩은 수분이 $10{\sim}13%$, 총당은 $55{\sim}70%$조 단백질은 $10{\sim}18%$조지방은 $0.2{\sim}1.0%$,회분은 $1.8{\sim}2.1%$이었다. 본 연구에서 제조한 누룩은 수분이 $12{\sim}15%$,총 당은 $61{\sim}71%$, 조단백질은 $15{\sim}20%$, 조지방은 $0.4{\sim}1.5%$, 회분은 $1.1{\sim}1.5%$이었다.