Chungkook-jang Koji Fermentation with Rice Straw

Chungkook-jang Koji was fermented with rice straw at for 72 hours. The changes of proximate composition, pH, titrable acidity, nitrogen compounds, protease activity and free-amino acids during the fermentation were investigated. Moisture, lipid and protein contents remained essentially unchanged during the fermentation. The pH was gradually increased from 6.4 to 7.46 and 7.82 at , respectively, after 72 hour fermentation. Amino type and water soluble nitrogen increased as fermentation progressed. however, the former slightly decreased after 60 hour fermentation. Chungkook-jang fermented at showed somewhat higher protease activity than . However, protease activity at both fermentation temperatures showed the same trend; that is, it increased until 48 hour fermentation and thereafter decrease. Free amino acid content of Chung-kook-jang after 72 hour fermentation at was 6 times greater than that of the steamed soybean, while it was 2.5 times greater at . Based on these results. it seems that the optimum fermentation conditions for Chungkook-jang were and 72 hours.