Traditional Soybean Paste Research Articles

传统豆酱发酵过程中细菌多样性动态

传统豆酱发酵过程中细菌多样性动态

A Study on Priorities Calculation among the Attributes and Products of Traditional Soybean Paste

A Study on Priorities Calculation among the Attributes and Products of Traditional Soybean Paste

A Study on Priorities Calculation among the Attributes and Products of Traditional Soybean Paste

A Study on Priorities Calculation among the Attributes and Products of Traditional Soybean Paste

Isolation, Identification, and Characterization of Pichia guilliermondii K123-1 and Candida fermentati SI, Producing Isoflavone β-Glycosidase to Hydrolyze Isoflavone Glycoside Efficiently, from the Korean Traditional Soybean Paste

A total of 155 microbial strains were isolated from the Korean traditional soybean paste based on their morphological features on the growth of agar plate. Among the isolated strains, a total of 28 strains were capable of hydrolyzing isoflavone glycoside to isoflavone aglycone efficiently in the soybean paste. Finally, two strains, K123-1 and SI, were selected because of their resistance to 15% NaCl and ability to convert isoflavone glycoside to isoflavone aglycone efficiently during the fermentation of soybean paste. The isolated strains K123-1 and SI were identified to be Pichia guilliermondii and Candida fermentati, respectively, using the partial 26S rDNA sequence analysis and phylogenic analysis. Pichia guilliermondii K123-1 and Candida fermentati SI converted daidzin to daidzein up to 96% and 95%, respectively, and genistin to genistein up to 92% when soybean pastes were fermented at for 20 days with a single isolated strain. Pichia guilliermondii K123-1 and Candida fermentati SI were able to grow in the presence of 15% NaCl on both liquid medium and agar plate. We think that Pichia guilliermondii K123-1 and Candida fermentati SI might be one of good candidates for making functional soybean paste because they are isolated from the Korean traditional soybean paste and have a good ability to convert isoflavone glycosides to isoflavone aglycones and a high salt tolerance.

Aspergillus sp. 101로부터 내염성 단백분해효소 생산을 위한 최적 조건 및 특성

Aspergillus sp. 101 was isolated from the Korean traditional soybean paste for the production of a salt-tolerant protease. The optimal condition for the production of a salt-tolerant protease was determined with various energy sources such as carbon, nitrogen, and protein, and at different culture conditions such as temperature, pH, incubation time and NaCl concentration. The most favorable organic nitrogen sources were 2% defatted soybean flour (DSF) and soy protein isolate (SPI). Optimal pH and temperature were pH 6.0 and 25~27 o C, respectively. Therefore, Aspergillus sp. 101 protease was a mild acid (or neutral) protease. Protease production was the highest at 0.1% concentration of CaCO3, K2HPO4 and Arabicgum. Aspergillus sp. 101 could grow in culture medium at 15% NaCl concentration and produce a salt-tolerant protease even at 7% NaCl. The cell mass and protease activity of Aspergillus sp. 101 cultured in a modified medium was comparatively higher in Czapek dox and protease producing media. Hence, Aspergillus sp. 101 protease can be utilized in soy or fish sauce industry as a salt-tolerant protease starter.

Changes in microbial community during Chinese traditional soybean paste fermentation

SummaryChinese soybean pastes have been widely used as condiments for hundreds of years in Asian countries. However, little research has been conducted on the microbiol population in the fermentation process. The present study investigated the changes in microbiol community during the 12 weeks fermentation of natural Chinese soybean pastes with polymerase chain reaction–denaturing gradient gcl electrophoresis. Bacillus megaterium, Lactobacillus plantarum, L. fermentum, B. amyloliquefaciens, and two uncultured bacteria were predominant strains during fermentation. DGGE analysis also identified the presence of Candida humilis, Kluyveromyces lactis, Zygosaccharomyces rouxii, and Williopsis saturnus. In the industrial production of Chinese fermented soybean paste, starter cultures only contained Z. rouxii and L. plantarum. However, our results showed that more microbes are involved in the natural fermentation of Chinese soybean paste.

Composition and safety analysis of Chinese traditional fermented soybean paste made by transgenic soybean

The traditional Chinese soybean paste was produced by cooked transgenic soybean fermentation with the composition of moisture 53%, amino acid 0.84% (calculated by nitrogen), votive sugar 6.21% and total acid 1.66%. A number of microorganism species were isolated and identified, including fungi and bacteria, and the bacterium species Rhizopus oryzae Went and Prinsen Geerligs were dominant in transgenic soybean paste. The results showed that the transgenic soybean paste contain abundant amino acids and vitamins (vitamin A, 42.87 IU; vitamin B, 10.31 mg; vitamin B, 20.64 mg; nicotinamide, 2.54 mg; pantothenic acid, 0.63 mg; vitamin B, 6,847 µg; folic acid, 105 µg; vitamin B, 123.85 µg; and biotin, 56.34 µg). Pathogenic microorganisms were not be detected in the transgenic fermented soybean paste.

Quality and Functional Characteristics of Chungkukjang Prepared with Various Bacillus sp. Isolated from Traditional Chungkukjang

Bacillus circulans, Brevibacillus brevis, B. 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 B. 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 1 (AFB 1 ) 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.