Effects of germination time of soybeans on quality characteristics of cheonggukjang fermented with an isolated bacterial strain

To investigate the effects of soybean germination time on the quality of cheonggukjang, the physicochemical characteristics and enzyme activities of cheonggukjang during fermentation were compared. B. subtilis SCD 115035 strain isolated from traditional cheonggukjang was selected for making cheonggukjang. Germinated (12-h) soybean-cheonggukjang produced the highest amount of viscous substance (13.22%) after 48 h of fermentation, and the contents were inversely proportional to the germination time of the soybeans. The acidic- and neutral-protease activities of ungerminated soybean-cheonggukjang were higher than those of germinated soybean-cheonggukjang . The amino nitrogen content of ungerminated soybean-cheonggukjang was the highest (436.93 mg%) at 48 h of fermentation, and its content was similar to that of 12-h germinated soybean-cheonggukjang . However, the total isoflavone content of 36-h germinated soybean-cheonggukjang was the highest after 72 h of fermentation, and its content was higher than those of cheonggukjang made from soybeans germinated for 0, 12, and 24 h.