• 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.

• 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.

• 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.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.83-89
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• 1995

Changes in physical, chemical and microbiological characteristics of rice-doenjang prepared with two different methods with or without soak treatment were investigated during 60 days of aging at $32^{\circ}C$ and $15^{\circ}C$. The pH of soak-treated rice-doenjang decreased slowly, but that of nonsoak-treated rice-doenjang decreased rapidly at the initial aging stage with the aging temperature of $32^{\circ}C$, resulting in pH 5.1 after the 60 days of aging time. Reducing sugar contents increased up to the $30{\sim}50$ days of aging time and decreased thereafter. The contents of soluble nitrogen, formol nitrogen, ammoniacal nitrogen and amino nitrogen were more affected by preparation methods than by aging temperatures. Color values depended not only on preparation methods but also on aging temperatures. There were no significant differences in the bacterial counts of rice-doenjang, while apparent differences in the yeast and mold counts by aging temperatures were observed. These results suggested that the properties of soak-treated rice-doenjang were less changed than those of nonsoak-treated rice-doenjang by aging time and temperature. And, with a view point of nitrogen compounds, aging time could be reduced by soak treatment.

• Food Science and Preservation
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• v.22 no.4
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• pp.545-552
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• 2015

This study investigated the quality characteristics of popped rice Doenjang prepared with different Bacillus strains (Bacillus subtilis KACC 15935, and Bacillus subtilis HJ18-9). The changes in the enzyme activity (protease, cellulase, and ${\alpha}$-amylase), amino-type nitrogen and ammonia-type nitrogen contents, and the reducing sugar were investigated during the fermentation period. Enzymes such as protease, cellulase, and a-amylase plays an important role in the changes in composition of nutrients, and in flavor and taste of popped rice Doenjang. Protease activities of the popped rice deonjang fermented with different Bacillus strains (control, B. subtilis KACC 15935, and B. subtilis HJ18-9) was in the range of 171.77-185.97 unit/g at the beginning of fermentation, and there were no significant differences among the samples. On the other hand, the protease activity in popped rice Doenjang fermented with B. subtilis HJ18-9 increased significantly up to $248.77{\pm}4.53unit/g$ at the end of fermentation (p<0.05). Cellulase activity and a-amylase activity of popped rice Doenjang in HJ18-9 was higher than these of other samples. After 56 days of fermentation, amino-type nitrogen in popped rice deonjang fermented with control, B. subtilis KACC 15935, and B. subtilis HJ18-9 increased significantly up to $174.99{\pm}3.70$, $166.59{\pm}1.40$, $225.39{\pm}3.70mg%$, respectively (p<0.05). These results suggested that B. subtilis HJ18-9 was a suitable starter for the preparation of soybean paste.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.3
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• pp.448-454
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• 1998

Meju for doenjang and kochujang was prepared as a model at Sunchang areaand monitored with major changes. Kochujang meju was prepared on September 12 and doenjang meju on November 12, 1995. Kochjang meju was found to be naturally fermented at 80~90% RH, 15~2$0^{\circ}C$ and doenjang meju was at 80~90% RH and 0~5$^{\circ}C$. The shapes of kochujang meju and doenjang meju were doughnut-type and rectangular, respectively. Weight losses during fermentation were 48% and 28%, respectively. The pH drop and acip production of kochujang meju were negligible. However, pH of doenjang meju decreased from 6.29 to 5.88 and acidity increased from 0.08 to 0.23% as lactic acid. Protein in meju was found to be rapidly solubilized during the early stage of fermentation. Soluble protein cotents of kochujang meju after 7 days and 60 days were 8.23%, respectively. The doenjang mejus were 2.15% after 20 days and 5.72% after 60 days. Soluble suger content increased with the fermentation time. The soluble sugar content was higher in kochjang meju. Acidic protease was highly produced during meju fermentation. $\alpha$-Amylase and $\beta$-amylase were detected in the kochujang meju, of which glutinous rice consisted, but negligible in doenjang meju. Lipase was detected in kochujang meju, but was, negligible in doenjang meju. Microbial population increased drastically after 7 days of fermentation in kochujang meju and 20 days of fermentation in doenjang meju.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.505-512
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• 2012

This study evaluated the quality characteristics of rice-doenjang prepared with Aspergillus oryzae MD05 and Bacillus subtilis HJ18-4. The physicochemical characteristics of rice-doenjang prepared with three types of meju, such as grain type(Rice 1), disc shape(Rice 2), and brick shape(Rice 3), were compared. We determined amino and ammonia nitrogen contents, protease and amylase activities, reducing sugar content, and total aerobic counts and lactic acid bacteria counts. The amino nitrogen and reducing sugar contents in all meju types gradually increased during fermentation. The amino nitrogen contents reached 151.5~200.0 mg%. Rice 3 were had the highest levels among the 4 types of rice-doenjang. After 42 days of fermentation, amylase and protease activity of Rice 3 were 366.57 and 94.26 unit/g, respectively, which were the highest levels among the 4 types of rice-doenjang. The total aerobic bacteria counts were not changed during 42-day fermentation. This results suggest that high quality characteristics of brick-shaped meju(Rice 3) were better than those of the other meju preparations.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1533-1541
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• 2016

Samples of doenjang (a fermented soybean paste) were prepared with different types of salts; purified salt (PS), 3-year-aged solar salt (SS3), 1-year-aged solar salt (SS1), and bamboo salt (BS, 3^rd processing product). For starter doenjang samples, selected starters comprising two bacilli, one yeast, and one fungus were inoculated, whereas for non-starter doenjang samples, microorganisms present in rice straw were inoculated after enrichment. The doenjang samples were fermented for 13 weeks at 25℃. During the fermentation period, SS and BS doenjang samples showed higher bacilli counts as well as much lower yeast counts than PS doenjang. At 13 weeks, yeast counts of starter doenjang samples were 7.75, 5.69, 6.08, and 4.74 log CFU/g for PS, SS3, SS1, and BS doenjang, respectively. For non-starter doenjang samples, counts were 7.17, 5.05, 5.92, and 4.54 log CFU/g for PS, SS3, SS1, and BS doenjang, respectively. SS and BS promoted growth of bacilli but inhibited growth of yeasts compared with PS. Debaryomyces hansenii was the dominant yeast in PS doenjang, whereas Candida guilliermondii and Pichia sorbitophila were dominant in SS and BS doenjang. In the sensory evaluation, SS and BS doenjang scored better than PS doenjang. In conclusion, SS and BS seem better than PS for production of high-quality 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.

• 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.