• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.132-139
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• 2004

This study was peformed in order to compare general components, color, free amino acid, fatty acid and organic acid contents between commercial doenjang (C-1, C-2, C-3) and green tea doenjang (GT). The moisture content in green tea doenjang was higher than that in commercial doenjang, but the contents of crude protein, carbohydrate and energy in commercial doenjang were higher than those in green tea doenjang. The crude lipid and fiber contents of commercial doenjang were similar to green tea doenjang. Catechin content of green tea doenjang was 2.3%. The total content of free amino acids in commercial doenjang ranged from 2,739∼6,380 mg% in which it showed wide variation among samples and the total content of free amino acids in green tea doenjang was 3000 mg%. Glutamic acid was almost high in commercial doenjang except one product but green tea doenjang was low. Linoleic acid (51%) was the highest content among the fatty acids. The major organic acid in both commercial and green tea doenjang was oxalic acid and its content in commercial times higher than in green tea doenjang. The antioxidant activity of green tea doenjang was higher than that of commercial doenjang.

• Food Science and Preservation
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• v.17 no.2
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• pp.243-249
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• 2010

We examined sensory characteristics to obtain the optimal conditions for doenjang preparation, using response surface methodology (RSM) to evaluate addition of sage (Salvia officinalis L.) powder to, and the salinity of, doenjang. We aimed to develop a new variety of doenjang linking traditional Korean doenjang preparation with the physiological functionalities of sage. Color values were 1.20-2.70, flavor values 1.60-3.20, taste values 1.40-3.50, texture scores 1.60-3.50, and overall preference values 1.60-3.05, with the differences depending on experimental variations in preparation. Analysis of a reaction surface formed by a quadratic regression equation found that the R-squared values for overall preference, texture, taste, flavor,and color were 0.11-0.41, thus relatively low and insignificant, being less than 5%. In sensory tests, the color value was 2.91 when the salinity was 21.50%, and sage powder was added to a concentration of 3.10% (all w/w). The flavor score was 3.21 when the salinity was 22.52% and sage powder concentration was 3.68%. The taste value was 2.87 when the salinity was 8.62% and sage powder concentration was 4.46%. The texture score was 2.88 when the salinity was 8.00% and sage powder concentration was 6.06%. The overall preference score was 2.74 when the salinity was 20.40% and sage powder concentration was 2.66%. Although this preparation method is new to Koreans, doenjang with added sage was associated with higher sensory scores than traditional doenjang, confirming the possibility of development of a novel functional doenjang.

• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.863-870
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• 2024

Meju, a fermented soybean brick, is a key component in soybean foods like doenjang and ganjang, harboring a variety of microorganisms, including bacteria and fungi. These microorganisms significantly contribute to the nutritional and sensory characteristics of doenjang and ganjang. Amplicon-based next-generation sequencing was applied to investigate how the microbial communities of meju fermented at low and high temperatures differ and how this variation affects the microbial communities of doenjang, a subsequently fermented soybean food. Our metagenomic data showed distinct patterns depending on the fermentation temperature. The microbial abundance in the bacterial community was increased under both temperatures during the fermentation of meju and doenjang. Weissella was the most abundant genus before the fermentation of meju, however, it was replaced by Bacillus at high temperature-fermented meju and lactic acid bacteria such as Weissella and Latilactobacillus at low temperature-fermented meju. Leuconostoc, Logiolactobacillus, and Tetragenococcus gradually took over the dominant role during the fermentation process of doenjang, replacing the previous dominant microorganisms. Mucor was dominant in the fungal community before and after meju fermentation, whereas Debaryomyces was dominant under both temperatures during doenjang fermentation. The dominant fungal genus of doenjang was not affected regardless of the fermentation temperature of meju. Strong correlations were shown for specific bacteria and fungi linked to specific fermentation temperatures. This study helps our understanding of meju fermentation process at different fermentation temperatures and highlights different bacteria and fungi associated with specific fermentation periods which may influence the nutritional and organoleptic properties of the final fermented soybean foods doenjang.

• KSBB Journal
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• v.27 no.6
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• pp.361-366
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• 2012

We investigated the anti-diabetic activity and enzymatic activity of 24 commercial doenjang samples certified for traditional foods. Twenty four doenjang samples showed the wide ranges in enzymatic activities (protease activities 0-50.45 unit/g, ${\alpha}$-amylase activities 0-675.9 unit/g, ${\beta}$-amylase 13.6-308.6 unit/g), and there were no difference in enzymatic activity by the producing region. To evaluate the potential anti-diabetic activity of 24 doenjang samples, we examined the effect of doenjang methanol extract (DME) on 2-[n-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amyno]-2-deoxy-d-glucose (2-NBDG) uptake. Ten samples among 24 samples significantly stimulated the uptake of 2-NBDG. When the cells were treated with DME at 400 ug/mL, No. 17 and 23 specially stimulated 2-NBDG uptake by 1.23-fold and 1.25-fold, respectively, compared with untreated control cell. And there were no cytotoxicity in the C2C12 cells treated with DME at concentration of 500 ug/mL. Among 24 samples, No. 6, 7, 12, 21 and 24 showed the ${\alpha}$-glucosidase inhibitor activity at concentration of 10 mg/mL; however, they were less effective than acarbose which is a commercial ${\alpha}$-glucosidase inhibitor.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.40-47
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• 2016

This study was conducted to evaluate the possible utility of 3 Aspergillus oryzae strains (designated as SCF-6, SCF-37, and JJSH-1), isolated from Korean traditional fermented materials, as starter cultures in the soybean paste industry. Doenjang (fermented soybean paste) was made with the A. oryzae strains described above, and its quality attributes were analyzed during a 60-day aging period. No significant differences in pH, moisture, or salt content were detected among the doenjang varieties made with the 3 Aspergillus strains. The concentration of amino-nitrogen, an indicator of doenjang aging, increased in each sample during the aging period. After the 60-day aging period, the contents of amino-nitrogen and free amino acid in doenjang made with SCF-6 showed the highest concentrations among the tested doenjang products: 971.6 and 8,064.9 mg%, respectively. Measurements of the color of doenjang showed that lightness and yellowness decreased during the aging period, but redness increased. After the 60-day aging period, the ${\gamma}$-aminobutyric-n-acid (GABA) concentrations in doenjang made with SCF-6 and SCF-37 were 61.3 and 53.7 mg%, respectively. In doenjang samples, aflatoxin was not detected and the concentrations of biogenic amines (histamine and tyramine) were 2.55-5.60 mg/kg and 3.70-5.87 mg/kg, respectively. These results indicated that A. oryzae SCF-6 isolated from traditional fermented foods could be useful as a starter culture in the soybean paste industry.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.172-176
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• 2012

Doenjang is a traditional Korean fermented soybean product that provides a major source of protein. In this study, a total of 18 different home-made doenjang samples were examined for the presence of foodborne pathogens and the total aflatoxin levels. Using an enzyme-linked immunosorbent assay to assess microbial quality and potential public health risk, we showed that total coliform levels in the doenjang samples ranged from 0 to $4.43{\pm}2.32{\times}10^6\;CFU/g$, and the maximum limit of Bacillus cereus was $4.67{\pm}2.0{\times}10^5\;CFU/g$. However, other foodborne pathogens, such as Staphylococcus aureus, Escherichia coli O157:H7 and Salmonella spp., were not detected among the tested samples. One of the samples (S3) showed a maximum limit of $42.2{\pm}9.1\;{\mu}g/kg$ for aflatoxin levels, which was above the safety limit allowed by the Codex Alimentarius Commission (CAC) regulatory agency. Further research is necessary to determine whether and how doenjang safety can be improved via elimination/reduction of microbial contamination during fermentation and storage or using microbial starter cultures for its fermentation.

• Journal of the Korean Society of Food Culture
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• v.35 no.5
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• pp.467-477
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• 2020

Doenjang is a major fermented soy-based food in Korea. Recent investigations have shown that fermented soybean foods have immunity-enhancing, anti-cancer, anti-obesity and anti-diabetic effects. Several studies also have reported that genistein and daidzein, which are easily absorbed in the body are produced in larger quantities in aged doenjang. The purpose of this study was to evaluate the variations in the anti-cancer effects of commercialized doenjang as it ages. Four groups were formed for this study according to aging periods of doenjang, namely short (under 5 years, S group), mid (under 10 years, M group), long (under 15 years, L group) and very long (over 15 years, E group). The anti-cancer effects of doenjang were determined by cell cytotoxicity assays in A549, YAC-1, and HepG2 cancer cell lines. Also, NK cell activity and splenocyte proliferation were assayed for cancer immunotherapy. The quantities of phenolic compounds in doenjang at different ages were also measured. The results showed that the anti-cancer effects increased in the S and M groups for all three cancer cell lines. Interestingly, similar to this result, splenocyte proliferation and NK activity were also the highest in the S and M groups. In contrast, the E group showed significantly reduced splenocyte proliferation. The quantity of phenolic compounds was similar to that of the anti-cancer results. Collectively, these results suggest that the fermentation period of doenjang plays a very important role in determining its anti-cancer effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.143-148
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• 2003

Antitumorigenic and antimutagenic activities of the doenjangs prepared from mushroom mycelia-cultured traditional mejus (designated to MTDJ) were investigated using the model of Sarcoma-180-induced mouse ascites cancer, and 2-amino-3-methylimidazo ［4,5-f］ quinoline (IQ) and aflatoxin B$_1$ (AFB$_1$) -mediated S. typhimurium mutagenicity, respectively. Antioxidative activity of MTDJ was also investigated using the mouse liver microsome system. Mushroom stains used for the preparation of the mushroom mycelia-cultured traditional mejus were Synryeong (Agaricus blazei), Yeonggi (Canoderma Iucidum), Sanghwang (Phellinus linteus), and Neutari (Pleurotus ostreatus). All MTDJS showed the enhanced antitumorigenicities (12% by Synryeong, 13% by Sanghwang, 16% by Yeonggi, and 19% by Neutari), antimutagenicity (6.1~20.8% for IQ and 3.1~10.2% for AFB$_1$), and antioxidative activity (6.6~46.5%), relative to the control doenjang. The $\beta$-D-glucan content (0.75~1.71 mg/g) of MTDJs was 3~8 times higher than that (0.22 mg/g) of the control doenjang. Genistein content (769~932 Ug/g) of MTDJS was also higher than that (728 Ug/g) of control doenjang The content of $\beta$-D-glucan and genistein was not exactly correlated to the antitumorigenicity and antimutagenicity of MTDJs. These results indicate that anti-tumorigenicity and antimutagenicity of MTDJS were elevated in comparison with the control doenjang, and the observed functions were, in part, derived from $\beta$-glucan and/or genistein in the MTDJS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.917-924
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• 1995

Four types of soybean paste(Doenjang), prepared with traditional Korean meju, natto meju, koji and mixture of koji and natto meju, were analyzed for compositions of free sugars and fatty acids. Crude protein content of the soybean pastes were ranged from 10.3~14.6% and in the order of traditional Korean soybena paste>natto soybena paste>koji & natto soybean paste>koji soybean paste during fermentation of Doenjang. Ethyl alcohol contnet was relatively higher in koji and natto soybean paste after fermentation for 75 days, and its content was the highest in koji soybean paste as 2.8% after fermenting for 90 days. Contents of total sugars and reducing sugars decreased during fermentation of doenjang in the order of koji soybena paste>koji and natto soybean paste>traditional soybean paste>natto soybean paste. Among the free sugars glucose, galactose, mannose and arabinose were identified in soybean paste, and glucose and galactose were more bundant. Contents of glucose and total free sugars were the highest in the traditional Korean soybean paste and galactose content was highest in koji soybean paste. In fatty acid compositions of soybean pastes, palmitic, stearic, oleic, linoleic, linolenic and arachidonic acids were analyzed, and the most abundant fatty acid was found to be oleic acid as 38.5~46.9% in all samples tested. But no significant differences in ratio of fatty acid compositions was observed from tested samples during the fermentation period.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.477-481
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• 1992

As a series of fundamental research projects to produce doenjang (Korean fermented soy paste) of better quality, two kinds of doenjang were manufactured from a traditional meju (Korean soy bean koji) and the mixed with Aspergillus oryzae and Bacillus natto, and histological changes in the cell structures of soy bean of the two were reported doenjang samples were observed and compared during the entire period of fermentation processes. Cell walls of the soy bean were ruptured by pressure and heat during the pressure cooking process and some of them were observed to have the ghost-like shapes. Remarkable differences in the plasmolysis of the cytoplasms were observed between the seed coat and the inner part of soy bean. Small vacuoles resulting from the fusion of the glycoprotein globules by protease and from the hydrolysis of the starch granules by amylase were also observed. Penetration of microorganisms was transferred from the seed coat to the inside of soy bean as the fermentation proceeded. Slimy substances were observed on the seed coat and the parenchyma cells of soy bean fermented with the mixed with Aspergillus oryzae and Bacillus natto. Cell walls of soy bean became difficult to stain and they showed unusual, polygonal shapes as the fermentation proceeded. Samples fermented with the mixed with Aspergillus oryzae and Bacillus natto showed more remarkable tendencies than traditional meju.