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As a first step to develop a doenjang possessing functional properties, microbial strains possessing proteolytic activity, fibrinolytic activity, and angiotensin-converting enzyme (ACE) inhibitory activity were screened and isolated from Korean traditional doenjang. First, total 264 isolates showing proteolytic activity were isolated from 14 different doenjang samples. Among them, 4 strains producing both of fibrinolytic activity and ACE inhibitor into the culture medium were selected. The levels of ACE inhibitory effect of G19, G26, P16, and P25 strains were about 82.5, 78.5, 74.5, and 75.6% of inhibition ratio in soybean powder broth, respectively. All isolates were identified as Bacillus amyloliquefaciens based on SDS-PAGE profiles of whole cell proteins and 16S rRNA gene sequence analysis. The result implied that the selected Bacillus strains could be used for the development of doenjang possessing functional properties as potential starter.

Summary Proteolytic activity, fibrinolytic activity and angiotensin converting enzyme (ACE)‐inhibitory activity, volatile compound profile, off‐flavour compound and sensory characteristics in soya bean paste made with Bacillus amyloliquefaciens KFCC11574P (KHG19) strain were compared with those in three different commercial soya bean paste samples. The KHG19 strain was isolated from doenjang, a traditional Korean soya bean paste, and the maximum dominance in soya bean paste prepared in this study was 68.8% after 2 months of ageing. Proteolytic and fibrinolytic activities in soya bean paste made with KHG19 strain (KHG19 soya bean paste) were higher than those in commercial soya bean pastes. The maximum proteolytic activity (2.47 cm2) was observed after 3 months of ageing, and the maximum relative fibrinolytic activity (236.98%) was appeared after 2 months of ageing. ACE‐inhibitory activity in KHG19 soya bean paste was similar to those in commercial samples. The volatile compound profile of KHG19 soya bean paste was closest to that of cheonggukjang according to the result from principal component analysis. The sensory score for off‐flavour character was significantly low in KHG19 soya bean paste (2.9) compare with the score (6.8) for Korean traditional doenjang. KHG19 strain can be used for the production of functional soya bean paste that would be affordable to global consumer.

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