Quality Characteristic of Hwangki(Astragalus membranaceus) Chungkukjang during Fermentation

Abstract

This study investigated the effects of a Hwangki (Astragalus membranaceus) extract on the quality of Chungkukjang fermented by Bacillus subtilis KCCM 12148, at 30, 40, and , for 4 days. Changes in moisture contents, protein levels, pH values, ammonia-type nitrogen levels, color, angiotensin-converting-enzyme (ACE) inhibition rates, and fibrinolytic activities, were all determined. For both control and test, the moisture contents decreased gradually with time and the protein levels increased slightly. The pH values fell at the beginning of fermentation and then rose. The content of ammonia-type nitrogen was higher in Hwangki with Chungkukjang than in control, until 24 hr after fermentation commenced. After that time, the content of ammonia-type nitrogen control was higher in the control than in the Hwangki with Chungkukjang sample. Color features, such as lightness, redness, and yellowness, all decreased during fermentation, in both control and test. The highest ACE inhibition rates during fermentation at were 90.9% in the control (48 hr after fermentation commenced) and 95.3% in Hwangki with Chungkukjang(24 hr). Fibrinolytic activities of Chungkukjang and Hwangki Chungkukjang were 100.7 and 74.4% respectively. The content of 2,6-dimethyl pyrazine in the control was higher than that in Hwangki with Chungkukjang. Sensory evaluationtests showed that the addition of Hwangki significantly improved the overall palatability of Chungkukjang.