• Preventive Nutrition and Food Science
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• v.14 no.2
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• pp.134-141
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• 2009

The changes in components and biological activities of doenjang samples prepared with black soybeans and fermented with Bacillus subtilis SCB were investigated. The amino nitrogen (A-N) contents of samples increased with increasing black soybean content. A doenjang product made using a 1:1 ratio of soybeans-black soybeans showed a maximum level of genistein and daidzein isoflavones ($1111.6{\mu}g/g$) at 110 days of fermentation, along with decreasing contents of genistin and daidzin due to the conversion to aglycones. The black soybean-only doenjang sample showed higher protease activity, including caseinolytic and fibrinolytic enzyme activities, than the other samples, and had relatively higher polyphenol content and DPPH radical scavenging activity. Therefore, doenjang made with additions of black soybeans and fermented by B. subtilis SCB may have improved physiological properties, suggesting this to be a valuable method of preparation.

• 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.

• Journal of Life Science
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• v.27 no.12
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• pp.1486-1493
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• 2017

Doenjang is a traditional korean fermented soybean paste made from meju (fermented soybean), which are fermented by diverse microorganisms including Bacillus subtilis and molds such as Rizopus, Mucor, and Aspergillus species The purpose of this study was to investigate the antiobesity effect of the black soybean doenjang (Korean fermented soybean pastes) in C57BL/6 mice. The anti-obesity effect was determined by measuring the release of adiponectin, leptin and adipogenic transcription factors by using reverse transcription-polymerase chain reaction and western blot. Weight gain was significantly reduced in the mice fed high fat diets (HFD) plus black soybean doenjang (HBD) compared to HFD mice. The HBD were also effective in improving the lipid profile. They significantly decreased the levels of serum triglyceride and cholesterol. In addition, they had a significantly down regulated impact on antiobesity factors; leptin level and increased adiponectin level. Also, mRNA and protein expression of two adipogenic transcription factors, SREBP-1c and $PPAR-{\gamma}$, in high fat with black soybean fed mice were markedly down regulated. These results indicate that the black soybean doenjang potentiates an anti-obesity effect by modulating lipid metabolism, thereby inhibiting adipogenic transcriptional activation.

• Nutrition Research and Practice
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• v.9 no.3
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• pp.235-241
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• 2015

BACKGROUND/OBJECTIVES: Doenjang, Korean traditional fermented soybean paste has been reported to have an anti-obesity effect. Because adipose tissue is considered a major source of inflammatory signals, we investigated the protective effects of Doenjang and steamed soybean on oxidative stress and inflammation in adipose tissue of diet-induced obese mice. MATERIALS/METHODS: Male C57BL/6J mice were fed a low fat diet (LF), a high-fat diet (HF), or a high-fat containing Doenjang diet (DJ) or a high-fat containing steamed soybean diet (SS) for 11 weeks. RESULTS: Mice fed a DJ diet showed significantly lower body and adipose tissue weights than those in the HF group. Although no significant differences in adipocyte size and number were observed among the HF diet-fed groups, consumption of Doenjang alleviated the incidence of crown-like structures in adipose tissue. Consistently, we observed significantly reduced mRNA levels of oxidative stress markers (heme oxygenase-1 and $p40^{phox}$), pro-inflammatory adipokines (tumor necrosis factor alpha and macrophage chemoattractant protein-1), macrophage markers (CD68 and CD11c), and a fibrosis marker (transforming growth factor beta 1) by Doenjang consumption. Gene expression of anti-inflammatory adipokine, adiponectin was significantly induced in the DJ group and the SS group compared to the HF group. The anti-oxidative stress and anti-inflammatory effects observed in mice fed an SS diet were not as effective as those in mice fed a DJ diet, suggesting that the bioactive compounds produced during fermentation and aging may be involved in the observed health-beneficial effects of Doenjang. CONCLUSIONS: Doenjang alleviated oxidative stress and restored the dysregulated expression of adipokine genes caused by excess adiposity. Therefore, Doenjang may ameliorate systemic inflammation and oxidative stress in obesity via inhibition of inflammatory signals of adipose tissue.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.458-463
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• 1999

Methanol extract and its fraction of traditional fermented soybean paste(doenjang) from Soonchang area were studied for growth suppression on the various tumor cells and suppression components, by using HPLC and GC were analysed. Hexane fraction of methanol extract was indicated 79%, 76%, 67%, 66%, 78% of growth suppression on L1210, P338D1, HepG2, WiDr and SNU 1 tumor cells, respectively. Ethylacetate fraction of methanol extract also showed 81%, 75%, 75%, 76% and 82% of growth suppression on the same tumor cells, respectively. Peak 8 obtained from HPLC of ethylacetate fraction indicated 81%, 77%, 77%, 75% and 79% of growth suppression on the same tumor cells and identified as a genistein, by comparing with standard one by HPLC analysis. Hexane fraction of methanol extract contained oleic acid, linoleic acid and palmitic acid.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.255-260
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• 1994

Four types of soybean paste(Doenjang), using traditional meju, koji, natto meju and mixture of koji and natto meju, were manufactured and fermented for 90 days. Analyzed volatile flavor components by GC-MS were confirmed to be thirty-six components including 5 alcohols, 5 aldehydes. 8 ketones, 3 acids, 9 esters and 6 miscellaneous ones. Traditional soybean paste tested had 29 components, koji and koji-natto soybean paste $26{\sim}24$ and natto soybean paste had 20 ones. Alcohol was found to be the most abundant volatile flavor components in all samples group. Traditional soybean paste had higher ratio of carbonyl to ester than any other types of soybean paste while koji-natto soybean paste had the lowest ratio of their components. The newly identified five volatile flavor components were 3-ethoxy-l-propene, dihydro-2-methyl-3-furanone. 1-hydroxy-2-propanone, 1-(2-furanyl)ethanone and 2-acethyl ethylhexanoate.

• 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 Microbiology and Biotechnology
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• v.26 no.1
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• pp.44-55
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• 2016

Bacillus cereus is a gram-positive, rod-shaped, spore-forming bacterium that has been isolated from contaminated fermented soybean food products and from the environment. B. cereus produces diarrheal and emetic toxins and has caused many outbreaks of foodborne diseases. In this study, we investigated whether B. amyloliquefaciens RD7-7, isolated from rice doenjang (Korean fermented soybean paste), a traditional Korean fermented soybean food, shows antimicrobial activity against B. cereus and regulates its toxin gene expression. B. amyloliquefaciens RD7-7 exhibited strong antibacterial activity against B. cereus and inhibited the expression of B. cereus toxin-related genes (groEL, nheA, nheC, and entFM). We also found that addition of water extracts of soybean and buckwheat soksungjang (Korean fermented soybean paste made in a short time) fermented with B. amyloliquefaciens RD7-7 significantly reduced the growth and toxin expression of B. cereus. These results indicate that B. amyloliquefaciens RD7-7 could be used to control B. cereus growth and toxin production in the fermented soybean food industry. Our findings also provide a basis for the development of candidate biological control agents against B. cereus to improve the safety of fermented soybean food products.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.666-674
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• 2016

The bacterial strains were screened as potential starters for fermenting low-salt doenjang (a Korean traditional fermented soybean paste) using Korean doenjang based on proteolytic and antipathogenic activities under 6.5-7.5% NaCl conditions. Phylogenetic analysis based on 16S rRNA gene sequences showed that they all belonged to the genus Bacillus. Proteolytic and antipathogenic activities against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Aspergillus flavus, as well as fibrinolytic, amylase, and cellulase activities of the 10 strains were quantitatively evaluated. Of these, strains D2-2, JJ-D34, and D12-5 were selected, based on their activities. The functional, phenotypic, and safety-related characteristics of these three strains were additionally investigated and strains D2-2 and D12-5, which lacked antibiotic resistance, were finally selected. Strains D2-2 and D12-5 produced poly-γ-glutamic acid and showed various enzyme activities, including α-glucosidase and β-glucosidase. Growth properties of strains D2-2 and D12-5 included wide temperature and pH ranges, growth in up to 16% NaCl, and weak anaerobic growth, suggesting that they facilitate low-salt doenjang fermentation. Strains D2-2 and D12-5 were not hemolytic, carried no toxin genes, and did not produce biogenic amines. These results suggest that strains D2-2 and D12-5 can serve as appropriate starter cultures for fermenting low-salt doenjang with high quality and safety.

• 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.