• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.234-241
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• 2019

In Korea, traditional doenjang is manufactured using the conventional method at home and by small-scale enterprises. Because this age-old process depends on natural inoculation of various microorganisms, it is difficult to reproduce or maintain consistency in the final product quality across batches. Moreover, doenjang occasionally prepared by this method raises safety concerns related to aflatoxin, biogenic amine, and Bacillus cereus contamination. To develop starters that can be conveniently used at home or in small industry settings for the manufacturing of safe and flavor-improved doenjang, autochthonous microbe starters were developed in dried forms as ready-to-use starters. Each starter powder prepared by heat- or freeze-drying methods remained stable even after 24-week storage. These ready- to-use starter powders were successfully applied to lab-scale fermentation for the production of safe and flavor-improved doenjang. We believe that these ready-to-use starter powders will benefit small-scale enterprises in the manufacturing of doenjang of good reproducible quality.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.266-271
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• 1994

In order to investigate the effects of the mixing ratio of rice on Doenjang, Meju Doenjang and Koji Doenjang were prepared respectively with oaring mix ratio of raw materials. The following results were obtained, after fermentation of up to 3 months. Significant differences between the kinds of Doenjang were not found in moisture and salt contents. Protein solubility $(water\;soluble\;nitrogen/total\;nitrogen{\times}100)$ was $32{\sim}50%$ and $14{\sim}24%$ in Koji Doenjang and Meju Doenjang, respectively. Protein digestibility $(formol\;nitrogen/total\;nitrogen{\times}100)$ was similar to the tendency of protein solubility. Reducing sugar content was $5{\sim}6%$ in Meju Doenjang, while $19{\sim}21%$ in Koji Doenjang. As the mixing ratio of rice increased, reducing sugar content also increased. Sensory evaluation showed that Koji Doenjang was desirable than Meju Doenjang and the mixing ratio of 20% rice was recommened for Koji Doenjang.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1587-1594
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• 2009

This study investigated the physico-chemical and sensory quality of Doenjang added with red pepper (Capsicum annuum L.) seed. The initial moisture content and salt content of Doenjang were 52.03-53.79% and 13.28-14.05%, respectively. The moisture and salt contents of Doenjang slightly decreased and increased, respectively, as fermentation periods increased. According to increasing fermentation periods, pH of Doenjang showed a little decreasing value although there were no difference between samples with various red pepper seed contents. On the other hand, titratable acidity of Doenjang increased as fermentation periods increased. Also, Doenjang added with red pepper seed had higher titratable acidity value than control Doenjang without red pepper seed. In the color of Doenjang, ‘L’ of lightness, ‘b’ of yellowness, and ‘a’ of redness were decreased as fermentation periods increased. Also, generally, increase of red pepper seed concentration resulted in higher values of redness (a), yellowness (b) and lightness (L) of Doenjang. Also, amino-type nitrogen content, which was 497-623 mg% in initial fermentation period samples, increased to 1,000 mg% for control and to 756~896 for red pepper added at the fermentation 120 days. In the total microbes, total cell count in the Doenjang samples was in the range of $10^7{\sim}10^8$ CFU/g regardless of fermentation periods. In contrast, yeast and mold number of Doenjang samples showed the range of $10^5$ CFU/g at the initial fermentation periods and decreased thereafter. In the sensory evaluation of Doenjang, unique Doenjang flavor increased regardless added red pepper seed as fermentation periods increased.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.323-328
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• 2010

After supplemention with the licorice (Glycyrrhiza glabra), mustard (Brassica juncea), and chitosan as food additives to low-salted doenjang containing 30% lower salt than control doenjang (12.7% salt), fermentation properties of doenjang were investigated for 40 days. Adding the licorice, mustard, and chitosan to low-salted doenjangs containing 10.2% and 8.9% of salt did not affect the acidity, viable cell count, or color of doenjang. A white pellicle-forming strain was detected at the surface of low-salted doenjangs (10.2% and 8.9% salt) but not the control doenjang and low-salted doenjangs added with mixed additives (licorice, mustard, and chitosan). The amino nitrogen content of 8.9% salted doenjang added with mixed additives at 20 days was 332 mg% and this value was similar to that of 12.7% salted doenjang at 40 days. In sensory evaluation, the 8.9% salted doenjang added the additives had the highest score in overall palatability. These results indicate that salt contents of doenjang could be lowered to 8.9% by adding licorice, mustard, and chitosan, resulting in improved palatability, shortened fermentation period, and inhibited abnormal fermentation.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.303-310
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• 2016

In this study, doenjang samples were prepared with different types of salts (12%, w/w): purified salt (PS), 3-year aged solar salt (SS3), 1-year aged solar salt (SS1), and bamboo salt melted 3 times (BS). Whole-soybean mejus were fermented with starters consisting of 2 Bacillus strains, a yeast, and a fungus (starter doenjang), and control mejus were fermented with organisms present naturally in rice straw (non-starter doenjang). The whole-soybean mejus were dried, and then mixed with cooked soybeans and the respective salts. The doenjang samples were fermented for 13 weeks at 25℃. The protease (acid, neutral, and alkaline) activities, fibrinolytic activities, and antioxidant capacities of the samples were examined every week. BS doenjang showed the highest acid protease (6.46 ± 0.20 unit/g) and fibrinolytic activities (0.61 unit/ml). Among the starter doenjang samples, those made with SS and BS showed the highest total phenolic contents after 91 days of fermentation. For antioxidant activities, SS3 doenjang showed higher activities than the other doenjang samples, as evaluated by ABTS, DPPH, and FRAP assays. These results suggest that solar salt, especially aged for 3 years, is better than purified salt in terms of producing better functionalities of doenjang.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.648-660
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• 2014

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.599-606
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• 2005

The study was carried out to measure the antitumor effect of traditional doenjang (Korean soybean paste) added with Japanese apricot, garlic or ginger. Four kinds of traditional doenjang inhibited significantly the tumor growth in mice injected sarcoma-I80 cells. Especially, traditional doenjang added with ginger (Gi-TD) showed an inhibition of tumor cell activity of 97% by the administration of 1.0 mg/kg methanol extracts. Among Balb/c mouse administered doenjang extracts, the liver weight of mice fed Gi-TD was heavier than that of the group not administered doenjang. However, no difference was found between the control and doenjang administrated groups in weights of body, spleen, kidney and heart. The activity of natural killer (NK) cells was relatively high in mice administrated with the four kinds of doenjang. Particularly, mice administrated with the Gi-TD methanol extracts showed a strong activity of 82.9%. The activity of glutathione S-transferase (GST) in mice administrated with the 4 kinds of doenjang was higher than that of the group not administered with doenjang. In particular, the GST activity was the strongest in the group administrated with Gi-TD. The results suggest that Gi-TD has a strong growth inhibition activity against sarcoma-180 tumor cells.

• Food Science and Preservation
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• v.13 no.6
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• pp.803-807
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• 2006

Browning of commercial Doenjang product during storage and marketing is a main concern in the industry. There have been many studies on the improvement on the quality of Doenjang during storage. In this study, phosphate and gas absorber treatment was introduced in manufacturing of Doenjang to improve the color of commercial Doenjang during storage. Doenjang treated with Phosphate and 9as absorber (sample C). Doenjang teated with Phosphate only (sample B), and the control (sample A) were prepared and their physicochemical and sensory properties were determined during storage at $30^{\circ}C$ for 28 days. Sample C was the best in terms of color as well as sensory evaluation resulting in preventing browning of Doenjang during storage. These result suggest that commercial production of Doenjang should introduce phosphate and gas absorber treatment to improve the quality of Doenjang, and to prevent undesirable browning reaction during storage and marketing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1525-1530
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• 2015

Doenjang made with various concentrations of salt solution such as 13, 14, 15, 16, 17, and 18% for making low-salt Doenjang. Physicochemical and sensory characteristics of Doenjang made with various concentrations of salt solution were analyzed. As a result, salt contents of Doenjang made with various concentrations of salt solution were 6.09~13.47%. Amino-type nitrogen showed a higher value when prepared with lower salt solution. The pH value increased with lower concentration of salt solution, whereas total acidity decreased with lower concentration of salt solution. The pH values and total acidity of Doenjang made with more than 16% salt solution were not statistically different. The reducing sugar content ranged from 1.39~6.30 mg/g, and higher salt content was associated with higher reducing sugar content. In the sensory descriptive analysis, Doenjang had the most salty taste at a salt concentration of 18%, whereas Doenjang at concentrations of 15%, 16%, and 17% did not show any statistical differences. In the consumer acceptance test, Doenjang made with 17% and 18% salt solution showed the highest score, followed by Doenjang made with 15% and 16% salt solution. In conclusion, the salty taste of Doenjang made with 16% salt solution might be used to make low-salt Doenjang. However, consumer acceptance of these Doenjangs was lower than that of Doenjang made with 17% and 18% salt solution.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.351-360
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• 1992

In order to improve the qualities of Doenjang were investigated on the enzyme activity in the koji and changes in chemical composition, flavors and sensory envaluation of Doenjang which were prepared with Rh. delemar koji, Asp. oryzae koji and traditional Meju with mixed koji and soybean as the ratio of optimum mixture. Asp. oryzae koji was indicated highest activities ${\alpha}$ and ${\beta}-amylase$ as 312 mg/ml, 235 mg/ml while Rh. delemar the lowest activities as 16 mg/ml, 38 mg/ml in aging for 40 days amino type ntrogen was the highest in the Asp. oryzae and Rh. delmear mixture koji(D group), Asp. oryzae(A group), and Asp. oryzae koji and Rh. delemar koji(C group) as 460 mg%, 440 mg% and 426 mg% in aging for 40 days. The main flavor components of Doenjang were detected as fellows phenol-2-kmethoxy, 4H-pyran-4-one-3-hydroxy-2-methyl, benzenthanol, 1-octan-3-ol, tetra-methyl pryrazine, 1,3,6 cyclooctatrien. Asp. oryzae(A) and Asp. oryzae koji with Rh. delemar koji mixture(C), group were the most excellent in taste, flavor color for fermented Doenjang at 40 days.