• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.116-124
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• 2010

Bacterial-koji was prepared by using B. subtilis DJI and Doenjang was prepared by using the bacterial-koji and purified salt or solar salt at 12% (w/v) concentration. Characteristics of the Doenjangs were examined after 2 months of aging. Moisture contents of the purified salt-Doenjang was decreased from 51.55% to 45.38% whereas that of the solar salt-Doenjang was decreased from 51.88% to 47.90%. Acidities of the Doenjangs were gradually increased. Hunter's L (lightness) color values of the Doenjangs were decreased. Browning reaction rate of purified salt-Doenjang was faster than solar salt-Doenjang. The content of free amino acids in solar salt-Doenjang was higher than those in purified salt-Doenjang. The major free amino acids of the Doenjang were glutamic acid (252.34 mg%~284.07 mg%), phenylalanine (184.72 mg%~224.71 mg%), leucine, tyrosine and valine.

• 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.

• 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.

• Food Science and Preservation
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• v.21 no.3
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• pp.434-441
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• 2014

This study investigated the quality characteristics and sensory evaluation of Doenjang samples made of soybean koji and prepared with Bacillus subtillus 3-B-1 and/or Aspergillus oryzae 6-M-1 isolated from traditional Meju, to replace the koji with wheat flour. Among the quality characteristics of doenjang during its fermentation at $30^{\circ}C$ for 40 days, its moisture decreased by degrees, but its amino-type nitrogen and reducing sugar increased by degrees. The color of the doenjang made of koji and prepared with Aspergillus oryzae 6-M-1 changed more significantly than that of the doenjang with Bacillus subtilis 3-B-1. The viable cell and mold counts increased by degrees during the fermentation. The results of the sensory evaluation of the doenjang made with koji and prepared with Aspergillus oryzae 6-M-1 did not significantly differ from those of the doenjang with Bacillus subtilis 3-B-1 and of the commercial doenjang. These results showed the possibility of preparing doenjang with soybean koji instead of wheat flour koji.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1035-1040
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• 2016

This study investigated the prevalence of foodborne pathogens and the bacterial community of traditional Doenjang collected from a longevity area in Korea as well as the antagonistic effect of traditional Doenjang isolates against Bacillus cereus to estimate the microbiological safety of traditional Doenjang. Aerobic bacteria showed $10^6{\sim}10^9CFU/g$, whereas coliform bacteria was not detected. Foodborne pathogens were not detected except B. cereus, which was detected in seven samples out of 10 Doenjang samples. A total of 327 isolates were identified from traditional Doenjang. The isolates consisted of Bacillus subtilis 155 (47.4%), Bacillus licheniformis 68 (20.8%), Bacillus amyloliquefaciens 46 (14.1%), and Bacillus pumilus 18 (5.5%). Antagonistic effect against B. cereus was detected in 20 (6.1%) of 327 isolates, which consisted of B. subtilis (12 strains), B. amyloliquefaciens (5 strains), and B. licheniformis (3 strains). The inhibitory zone for the antagonistic effect was 9.0~12.0 mm in diameter. Although a small amount of traditional Doenjang was tested in this study, these results indicated that the potential risk of B. cereus in traditional Doenjang is lower than generally presumed. It is necessary to monitor the antagonistic effect of traditional Doenjang isolates against B. cereus.

• Culinary science and hospitality research
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• v.17 no.5
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• pp.241-252
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• 2011

The study was carried out to evaluate the anticancer effects in Korean soybean paste(doenjang) added with sun-dried salt(S-D), roasted salt(R-D), bamboo salt roasted once(B1-D) or bamboo salt roasted nine times(B9-D). In MTT assay, S-D, R-D, B1-D and B9-D exhibited a significant inhibitory activity(64-87% and 68-92%) against the proliferation of AGS human gastric adenocarcinoma cells by adding 0.05% and 0.1% of methanol extract. Among Balb/c mice injected with sarcoma-180 cells, the bodies, livers, spleens, kidneys and heart weight of the mice administered with 4 kinds of doenjang extracts were heavier than the non-administered ones of the group. However, no difference was found between the control and doenjang administered groups. Four kinds of doenjang inhibited significantly the tumor growth, especially R-D and B1-D showing an inhibition of tumor cell growth up to 97% by the administration of 1.0 mg/kg methanol extracts of doenjang. The activity of natural killer(NK) cells was relatively high in mice administered with four kinds of doenjang. Particularly, mice administered with R-D methanol extract showed a stronger activity of 88.2%. The activity of glutathione S-transferase(GST) in mice administered with four kinds of doenjang was higher than that of the non-administered group. In particular, the GST activity was the strongest in the group with B1-D. As these results indicate the various kinds of salt have different effects on the anticancer activity of doenjang.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1258-1265
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• 2000

In oder to acquire microbial agents that can be utilized for control of aflatoxin produced by Aspergillus. flavus and Asp. parasiticus, antifungal bacteria were isolated. Antifungal bacteria was identified as Bacillus spp. based on morphology and physico-biochemical characteristics. Amount of aflatoxin $B_1$ from Doenjang(soybean paste) prepared with Asp. flavus, Asp. parasiticus, antifungal bacteria(Bacillus sp.), or mixture of Asp. flavus and Asp. parasiticus was 27.2 ppb, 30.3 ppb, 3.4 ppb, and 3.7 ppb, respectively. Aflatoxin $B_1$ was not detected from Doenjang(control) and Doenjang prepared with antifungal bacteria. Content and compositions of free sugars, fatty acid, organic acid and free amino acid in Doenjang prepared with Asp. flavus and Asp. parasiticus, antifungal bacteria and mixture of Asp. flavus and Asp. parasiticus were not significantly different. For volatile flavor compounds of Doenjang prepared with antifungal bacteria, 2-pentyl furan and butanoic acid were disappeared or reduced, while octadecene compounds were produced. However, those of Doenjang prepared with Asp. flavus or Asp. parasiticus and Doenjang(control) were not significantly different. These results suggested that the antifungal bacteria(Bacillus sp.) inhibited production of aflatoxin and that antifungal bacteria did not effect the quality of Doenjang.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.3
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• pp.372-379
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• 2016

This study was performed to investigate the quality characteristics of various salted (8, 10, and 12%) Doenjang prepared with fermented Hwangchil (Dendropanax morbifera) extract as well as the effect of Bacillus methylotrophicus S8 strain, isolated from soy sauce, as a starter culture. After fermentation, the total cell number of low-salted Doenjang (8% and 10%) prepared with fermented Hwangchil was lower than that of Doenjang without fermented Hwangchil. Low-salted Doenjang (8% and 10%) showed higher total acidity, amino acid, and organic acid levels as well lower pH levels than high-salted Doenjang (12%), indicating active fermentation. The highest levels of lactic acid (48.1 mg/L) and glutamic acid (549.0 mg/L) were observed in low-salted Doenjang (8%) fermented with B. methylotrophicus S8 strain. The low-salted Doenjang (8%) fermented with B. methylotrophicus S8 also showed the highest score in overall preference of sensory evaluation. These results indicate that Hwangchil extract fermented with B. methylotrophicus S8 can be used as a starter for making low-salted Doenjang, resulting in improved palatability, and inhibition of abnormal fermentation.

• Food Science and Preservation
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• v.18 no.6
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• pp.859-868
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• 2011

This study was conducted to determine the appropriate mixing ratio of Koji and rice Doenjang. Brown rice Doenjang (BR) was prepared with three different ratios of cooked soybean to brown rice Koji [1.5:1 (BR-1); 2:1 (BR-2); and 3:1 (BR-3)], and polished-rice Doenjang (PR) was prepared with cooked soybean and polished-rice Koji (2:1). The components related to the quality of Doenjang were analyzed during 60-day aging. No significant differences were found in the moisture and salt contents between the brown rice Doenjang and the polished-rice Doenjang. The pH, titratable acidity, and bacteria cells increased at 20-30 days aging time, and decreased thereafter. The reducing-sugar and ethyl alcohol contents, on the other hand, increased at 10-20 days previously. These analytical values of the physicochemical and microbiological characteristics increased with the increase in the percentage of koji in each Doenjang. The amino-nitrogen and free-amino-acid contents showed the highest levels in BR-1: 887.6 and $4047.0{\pm}1.5$ mg%, respectively. The ${\gamma}$-aminobutyric-acid (GABA) contents slightly increased with increasing aging time. In the color of Doenjang, the lightness and yellowness increased along with the aging time, but the redness decreased as the aging time increased. These results showed that BR-1 processed the fermentation the fastest compared with the others. Moreover, the reducing-sugar, ethanol, and free-amino-acid contents as palatable components increased rapidly until 30 days aging time.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1210-1214
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• 2010

Many bacteria are involved in the fermentation of doenjang, and Bacillus species are known to perform significant roles. Although SDS-PAGE has been frequently used to classify and identify bacteria in various samples, the microbial diversity in doenjang has not yet been investigated. This study aims to determine the identity and distribution of dominant Bacillus species in doenjang using SDS-PAGE profiles of whole-cell proteins and 16S rRNA gene sequencing. Reference Bacillus strains yielded differential SDS-PAGE banding patterns that could be considered to be highly specific fingerprints. Grouping of bacterial strains isolated from doenjang samples by whole-cell protein patterns was confirmed by analysis of their 16S rRNA gene sequences. B. subtilis was found to be the most dominant strain in most of the samples, whereas B. licheniformis and B. amyloliquefaciens were less frequently found but were also detected in several samples. The results obtained in this study show that a combined identification method using SDS-PAGE profiles of whole-cell proteins and subsequent 16S rRNA gene sequence analysis could successfully identify Bacillus species isolated from doenjang.