Manufacture of chungkuk-jang with elastase activity

Chungkuk-jang (hereafter referred to simply as jang), a traditional fermented soybean product in Korea, is manufactured by a process similar to that of Japanese itohiki-natto (referred to as natto). The bacteria isolated from jang were identified to belong to Bacillus subtilis (Ehrenberg) Cohn. The quality of jang manufactured with the isolated bacteria and two kinds of natto bacilli, B. subtilis (natto) KFP2 and KFP419, was evaluated to be as good in sensory evaluation except for the viscosity. Therefore, the isolated bacteria were estimated as B. subtilis (natto). In jang, soybean proteins were degraded to increase soluble and formol nitrogens. Sticky materials were produced, and natto-like flavor was emitted. Jang prepared in the laboratory showed elastase activity, and it was twice-to-three-times higher than that of the commercial product. While jang is a different product from that of natto, both products contain the common starter and elastase.