• Journal of the Korean Society of Food Culture
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• v.13 no.1
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• pp.59-64
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• 1998

In order to find causes of the difference in taste between Korean and Japanese soybean paste, comparian was made on the free amino acids composition in soybean paste in those two countries. It was found that the free amino acid composition of commercial soybean paste made in Korea was analogous to homemade soybean paste, and the commercial soybean paste made in Japan, was analogous to homemade soybean paste. And there was a similarity on the point that the glutamic acid content was the highest of all free amino acids content in both Korean and Japanese soybean pastes. There was a difference in the mean total free amino acids content between Korean and Japanese soybean paste. The mean ratio of the glutamic acid content to total free amino acid content in Korean and Japanese soybean paste was on the range of $11.5%{\sim}22.6%$ and $10.4%{\sim}12.5%$, respectively. These results suggest that glutamic acid determines taste in Korean and Japanese soybean paste.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.357-365
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• 2018

The quality of Korean doenjang, which was traditionally made for this study, was monitored for physicochemical properties, antioxidant capacity, and sensory properties at six months intervals for three years. The collected data were comprehensively analyzed using the k-means clustering via principal component analysis (PCA) to determine the optimal intake duration and sensory factors associated with acceptance. Doenjang samples were classified with every year interval based on PCA, and then the classified doenjang samples were further grouped into cluster one, two, and three based on the k-means clustering. In Cluster three, doenjang that was aged for thirty and thirty-six months, respectively, showed high total phenolic content, antioxidant capacity, superoxide dismutase like activity, and 2,2-diphenyl-1-picryl-hydrazyl radical scavenging capacity. Interestingly, along with acceptance, the levels of free amino acids and organic acids were higher in Cluster 3. The sensory factors found to be associated with acceptance included umami taste and brown color. In conclusion, this study proposes the intake of doenjang aged for thirty months based on its antioxidant activity and sensory properties although doenjang is usually ready after twelve months of aging.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.84-88
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• 2001

About 100 bacterial strains producing proteolytic enzymes were isolated from Korean traditional soy paste Doenjang. Among them, strain SYG3 producing the highest level of angiotensin converting enzyme (ACE) inhibitor into the culture medium was selected and identified as Bacillus pumilus according to the Bergey's mannual of systematic bacteriology. Soybean powder as a nitrogen source and glucose as a carbon source supported high level of ACE inhibitor production. The presence of 3% NaCl also enhanced the production of ACE inhibitor in the medium. The optimum initial pH of the medium and culture temperature for the production of ACE inhibitor were 7.0 and $32^{\circ}C$, respectively. The maximal level of ACE inhibitory effect was obtained after 36 hours of cultivation under the optimized conditions, which was about 98% of inhibition ratio.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.133-138
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• 2001

Toxicological safety on 20 kGy-gamma irradiated Kanjang (soy sauce), Doenjang (soybean paste), Kochujang (hot pepper paste) and Chunghukjang (soy paste) was determined by SOS Chromotest. As the strain of the SOS Chromotest, Escherichia coli PQ37 was used in the condition of presence or absence of an exogenous metabolizing system (S-9 mix). Water extract or organic solvent extract was prepared from samples, concentrated and tested by SOS Chromotest with S-9 mix or not. All irradiated samples were not different from non-irradiated one in the bacterial assay maintaining the below 1.5 of IF(induction factor) values in the adapted dose of 10,000$\mu\textrm{g}$/assay. The results indicated that any mutagenicity was not observed in 20 kGy-irradiated traditional soybean fermented foods.

• Preventive Nutrition and Food Science
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• v.4 no.4
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• pp.260-264
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• 1999

Korean traditional fermented soy paste (doenjang) prolonged the life span of Balb/c mice injected with the sarcoma-180 cells. The activities of liver enzymes, such as xanthine oxidase, aminopyrine N-demethylase, aniline hydroxylase, ${\gamma}$-glutamylcysteine synthetase, glutathione reductase and glutathione S-transferase (GST), and the contents of lipid peroxide and glutathione were determined from the sarcoma-180 cell injected mice that were treated with methanol extracts from doenjang, miso and soybean. The content of lipid peroxide and the activity of xanthine oxidase in the liver of Balb/c mice which were increased by the transplantation of the sarcoma-180 cells were decreased by treatment with the methanol extract from doenjang. But the activities of aminopyrine N-dementhylase and aniline hydroxylase were not affected by the treatment of methanol extracts from doenjang to the mice injected with the sarcoma-180 cells. The content of glutathione, the activities of glutamylcysteine synthetase, glutathione reductase and glutathione S-transferase decreased by the injection of the sarcoma-180 were recovered considerably by the treatment of the methanol extract from doenjang.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.828-831
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• 2005

The content of vitamin $D_2$, including its precursor ergosterol, was determined in some cultivated mushrooms to manufacture fortified Doenjang (Korean traditional soybean paste) with vitamin D by supplementation with mushroom. Ergosterol was the most abundant sterol in the mushrooms (50 to 140 mg/100 g dry weight) but the ergocalciferol portion made up only 0.065% (Pleurotus eryngii) to 2.5% (stipe part of Lentinus edodes, shiitake) of the total vitamin $D_2$ of each mushroom. Changes in these compounds in L. edodes caused by UV or solar irradiation were also evaluated. Ergocalciferol content in the pileus part of L. edodes went up to $424\;{\mu}g/100\;g$ dry weight and ergosterol levels reached 139.3 mg per 100 g dry weight at maximum levels. Ergocalciferol content increased about 50% when exposed to solar radiation and increased 377% with UV irradiation. These compounds level in Doenjang was enriched as much as supplied UV irradiated L. edodes powder to before fermentation, and the supplemented mushroom did not influence the palatability of Doenjang.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.275-280
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• 2011

In order to evaluate the diversity and change of bacterial population during the manufacturing process of traditional soybean paste (doenjang), bacterial communities were analyzed using 16S rRNA gene-based pyrosequencing. In rice straw, the most important inoculum source for fermentation, the bacterial sequences with a relative abundance greater than 1% were assigned to four phyla, Proteobacteria (71%), Actinobacteria (20.6%), Bacteroidetes (4.2%), and Firmicutes (1.3%). Unlike bacterial community composition of rice straw, a different pattern of bacterial population in meju was observed with predominantly high abundance (99.1%) of Firmicutes. Phylum composition in young doenjang was almost same as that of meju. Major genera in young doenjang were Bacillus (81.3%), Clostridium (6.9%) and Enterococcus (6.3%) and the predominant species among bacterial population was B. amyloliquefaciens (63.6%). Abundance of the phylum Firmicutes in mature doenjang was 99.98%, which was even higher value than those in meju and young doenjang. Predominant species in mature doenjang were B. amyloliquefaciens (67.3%), B. atrophaeus (12.7%), B. methylotrophicus (6.5%), B. mojavensis (3.2%), and B. subtilis. (2.5%), which were also identified as major species of the microbial flora in meju. These results suggested that rice straw was a primary source for supplement of Bacillus species in manufacturing the traditional doenjang and that some species of Bacillus strains were mainly involved in the fermentation process of traditional doenjang.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.361-368
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• 2011

Three types of doenjang were prepared with regular soybean, germinated regular soybean, and a mixture of germinated regular and black soybean. After 90 days of fermentation, pH, moisture, and salt contents of doenjang were $6.01{\pm}0.01-6.72{\pm}0.01$, $53.78{\pm}0.22-57.99{\pm}0.11$, and $14.17{\pm}0.06-15.03{\pm}0.21%$, respectively, showing slight differences according to soybean germination. Amylase and protease activity of doenjang changed similarly during fermentation in all samples. Amino-type nitrogen and free amino acid content of germinated black soybean doenjang after 90 days of fermentation were $1256.21{\pm}1.86$ and 994.46 mg%, respectively, which were higher than those of other samples. A sensory evaluation of germinated regular soybean doenjang showed the highest scores for color, taste, and overall acceptability. These results suggest that high sensory quality doenjang can be prepared using germinated regular soybean and a mixture of germinated regular soybean and black soybean.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.285-291
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• 2008

A potential probiotics bacterial strain, CS90, was isolated from Korean soybean paste (doenjang). The strain CS90 showed antimicrobial activity against food-borne pathogenic bacteria including Salmonella enterica, Salmonella enteritids, Salmonella typhymurium, Bacillus cereus, Listeria ivanovii, Listeria. monocytogenes, Sthaphylococcus aureus, and Sthaphylococcus epidermidis and showed a significant survival rate of 35.7 to 57.8% under the artificial gastric acidic condition (pH 2 to 3). The strain CS90 was classified as Bacillus subtilis based on morphological, physiological, chemotaxonomic features and phylogenetic analysis based on 16S rDNA sequence and designated as B. subtilis CS90. B. subtilis CS90 can be used as a potential probiotics.

• Journal of Applied Biological Chemistry
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• v.48 no.3
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• pp.138-143
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• 2005

Antibacterial, free radical scavenging, proliferative, and cytotoxicity effects of Doenjang extracts were examined. All samples except water extract showed strong antibacterial activity against oral bacteria, Streptococcus. pyogenes, S. mutants, S. sanguinis, S. sorbrinus, S. criceti, S. antinosus, S. gordonii, and Porphyromonas. gingivalis (MIC and MBC values: 0.08-1.25 and 0.16-2.50 mg/ml, respectively). DPPH method showed ethanol and ethyl acetate extracts are effective inhibitors of oral bacteria. Based on MTT assay, 24 h exposure to 0.31 mg/ml of all extracts, excepted water extract, resulted in strong cytotoxicity on KB cells. All extracts strongly inhibited human gingival fibroblast viability.