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In order to improve the quality of commercially manufactured Doenjang, yeast florae, gas and alcohol formation during fermentation of Doenjang were periodically examined. Candida rugosa, Candida zeylanoides, Pichia farinosa, Saccharomyces cerevisiae and Zygosaccharomyces rouxii were isolated and identified from Doenjang at various fermentation stage. S. cerevisiae and Z. rouxii showed distintive gas and alcohol formation activities and the distribution ratio of Z. rouxii was 26% at 14 days and ?6% as prevailed yeast strain after 30 days fermentation, respectively. Ethanol content of Doenjang was gradually increased into 2.19% at final stage of fermentation. The amount of gas generated during fermentation was 9.75 ㎖/g after 14 days, 4.5 ㎖/g after 30 days and decreased into negligible amount after 45 days fermentation. These inhibitory effects on gas generation by fermentation period would be ascribed to the ethanol produced for fermentation. This results suggest that gas generation in commercially manufactured Doenjang could be eliminated through the effective control of fermentation by yeast without application of any preservatives.
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