• 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.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.39-44
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• 1994

For the purpose of supplying the basic knowledge to make Doenjang which is acceptable to Korean people three kinds of koji, namely rice, wheat, and soybean Koji were made with Aspegillus oryzae. Then Doenjangs were made with four different ratio of three Kinds of Koji. Components related to the taste of Boenjang were analyzed, sensory evaluation of Doenjang were made, and correlation between analytical variables and sensory parameters were investigated. The results were as followed 1. Total nitrogen contents of each Doenjang were increased with increasing the ratio of Koji except Doenjang made with soybean Koji. The amounts of amino nitrogen increased with the ratio of koji increases in each Doenjang. Amino nitrogen contents of Doenjang made with soybean Koji were highe. than the others, 2. Reducing sugar contents of rice and wheat Doenjang were similar, but amounts were increased with increasing the ratio of Koji Reducing sugar contents of Soybean Doenjang were lower than the others. pH of the Doenjangs decreased as the ratio of the koji increased. The amount of sweet taste amino acids and MSf; like amino acids were increased, but bitter taste amino acids were decreased as the ratio of the koji increased in rice and wheat Doeujang, The sweet taste amino acids and bitter taste amino acids in soybean Doenjang showed little Changes in amount, but the amount of MSG like amino acids increased as the ratio of the Koji increased from 13% to 25%, 37%, and 50%. The nucleotide contents of wheat Doenjang were higher than other Doenjangs, and there is a tendency to increase the amounts of nucleotide as increasing the ratio of koji in each Doenjang. 3. As a result of sensory evaluation, wheat Doenjang of 13% koji ranked highest in the overall eating quality, and Doenjangs made with 50% and 37% of rice koji ranked next, 4. pH and sweet tast amino acids influenced on the Overall eating quality of the Doenjang, however most compo-nents of the Doenjang seemed to relate to overall eating quality of Doenjang, however most components of the Doenjang seemed to relate to overall eating quality of Doenjang.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1114-1121
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• 2000

Monascus koji have been used as a natural food colorant and preservative in Asia countries for centuries. This study was investigated to the chemical properties of Doenjang prepared with Monascus koji. Four kinds of Doenjang were fermented with Aspergillus koji only and Aspergillus koji plus 10%, 20% and 30% Monascus koji of its amount, respectively, and the changes of characteristics were investigated during fermentation. All the Monascus koji substituted Doenjang showed lower protease activities than Aspergillus koji Doenjang over all periods of fermentation. No differences of amino nitrogen and free amino acids were found after 30 days of fermentation and reducing sugars and peptides were found during over all periods of fermentation in each other. The Monascus koji gave higher a-, L- and C-values and lower h-values than Aspergillus koji. Sensory profiles of color, flavor, taste and overall quality on the final products which fermented during 60 days, indicated that there were no differences each other. From these results Monascus koji suggested as 30% substitutes for Aspergillus koji in Doenjang preparation.

• 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.

• 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.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.609-615
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• 1994

Fermented traditional soybean paste(doenjang), koji soybean paste by Aspergillus oryzae, natto soybean paste by Bacillus natto and koji & natto soybean paste by Aspergillus oryzae and Bacillus natto were analyzed for compositions of amino acids and contents of nitrogens. Amino type nitrogen was the highest in fermenting for 90 days as $271{\sim}868\;mg/100g$, and its contents were in the order of koji soybean paste>traditional soybean paste>koji & natto soybean paste>natto soybean paste in all samples tested. In compositions of total amino acids, glutamic and aspartic acids were rich in koji soybean paste but big differences were not observed in all samples. But some differences were observed in free amino acid compositions in all samples, that is, glutamic acid, tyrosine, lysine and aspartic acid were detected more abundantly. Sum of free amino acids for 90 days were in order of koji soybean paste>traditional soybean paste>koji & natto soybean paste>natto soybean paste. The ratios of free to total amino acids were $3.28{\sim}19.81%$ for 45 days, but increased to $10.88{\sim}25.10%$ for 90 days, and in order of traditional doenjang>koji doenjang>koji & natto doenjang>natto doenjang. Methionine and histidine showed higher ratios of free to total amino acid but lower in glutamic acid and aspartic acid. These results suggest that koji and traditional soybean paste of having high ratios of free amino acids to free and total amino acids may be more favorable in soybean paste 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.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.529-537
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• 2012

This study examined the manufacturing characteristics of sweet potato doenjang in order to gain a more efficient use of the sweet potato. Sweet potato(Sinwhangmi, Sinjami) koji(mixed sweet potato paste and soybean powder in a ratio of 1:1) was cultured with Aspergillus oryzae KCCM 11372 at $35^{\circ}C$ for 48 h. Sweet potato doenjang was fermented for 60 days using a sweet potato koji(20%, 45%) and steamed soybean(70%, 45%), with salt accounting for 10%. The glutamic acid content was determined to be much higher in sweet potato doenjang using Sinwhangmi koji(45%) and steamed soybean (45%), than that of general doenjang. The DPPH radical scavenging activity has the largest $EC_{50}$(0.9 mg) in sweet potato doenjang using Sinjami potatoes 45%. Sensory evaluation indicated a good preference for sweet potato doenjang using Sinwhangmi(45%) and steamed soybean(45%).

• 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.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1397-1404
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• 2014

A few starters have been developed and used for doenjang fermentation but often without safety evaluation. Filamentous fungi were isolated from industrial doenjang koji, and their potential for mycotoxin production was evaluated. Two fungi were isolated; one was more dominantly present (90%). Both greenish (SNU-G) and whitish (SNU-W) fungi showed 97% and 95% internal transcribed spacer sequence identities to Aspergillus oryzae/flavus, respectively. However, the SmaI digestion pattern of their genomic DNA suggested that both belong to A. oryzae. Moreover, both fungi had morphological characteristics similar to that of A. oryzae. SNU-G and SNU-W did not form sclerotia, which is a typical characteristic of A. oryzae. Therefore, both fungi were identified to be A. oryzae. In aflatoxin gene cluster analysis, both fungi had norB-cypA genes similar to that of A. oryzae. Consistent with this, aflatoxins were not detected in SNU-G and SNU-W using ammonia vapor, TLC, and HPLC analyses. Both fungi seemed to have a whole cyclopiazonic acid (CPA) gene cluster based on PCR of the maoA, dmaT, and pks-nrps genes, which are key genes for CPA biosynthesis. However, CPA was not detected in TLC and HPLC analyses. Therefore, both fungi seem to be safe to use as doenjang koji starters and may be suitable fungal candidates for further development of starters for traditional doenjang fermentation.