Quality and functional characteristics of chungkukjang prepared with vargous Bacillus sp isolated from traditional chungkukjang

摘要

Bacillus circulans, Brevibacillus brevis, R licheniformis, B. coagulans, B. subtilis, and B. sterothermophillus were isolated and identified from chungkukjangs (Korean traditional soybean paste fermented for a few day). Chungkukjang was prepared on a laboratory scale with soybeans and the isolated strains. Characteristics of the chungkukjangs including slime material content, free amino acid content, sensory qualities, and antimutagenicity were determined. The content of slime material, which is an important indicator of the quality of chungkukjang, was highest in B. licheniformis-inoculated chungkukjang, and lowest in B. sterothermophillus-inoculated chungkukjang. The total content of glycine, glutamic acid, aspartic acid, and arginine, which contribute a savory taste to chungkukjangs, was highest in B. licheniformis-inoculated chungkukjang. The content of leucine, which gives a bitter taste, was highest in B. brevis-inoculated chungkukjang. Sensory evaluation revealed that chungkukjangs made using R licheniformis and B. subtilis had a weak bitter taste and strong sweet and savory taste and good color, so their overall acceptability was high. Chungkukjang fermented with B. circulans and B. licheniformis inhibited N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) mutagenicity by more than 80%. B. licheniformis-inoculated chungkukjang exhibited the highest antimutagenicity against and aflatoxin B, (AFB,) and MNNG. These results suggest that using B. licheniformis to ferment chungkukjang increases the antimutagenic properties and improves the sweet and savory taste by increasing glycine, glutamic acid, aspartic acid, and arginine concentrations.