• Food Science and Preservation
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• v.16 no.4
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• pp.554-561
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• 2009

We investigated the antioxidative effects of solvent extracts of doenjang fermented using Bacillus subtilis DJI (DJI doenjang) in vitro. The solvents used for extraction were ethanol, n-hexane, and water. The antioxidative activities of DJI doenjang solvent extracts were measured by estimation of peroxide value, the presence of linoleic acid level, and nitrite scavenging activity, the Rancimat test, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) free-radical generation, in comparison with the commercial antioxidant butylated hydroxytoluene (BHT). The peroxide value of an ethanol extract was lower than those obtained using n-hexane and water extracts. Furthermore, the peroxide value of the ethanol extract was similar to that obtained after BHT treatment. The nitrite scavenging activity was 23.36% after addition of 600 ppm DJI doenjang ethanol extract, and the DPPH free-radical scavenging activity was 19.06% under same condition, which shows that DJI doenjang ethanol extract exhibited lower antioxidative capacities than did BHT. In the Rancimat test, the ethanol extract (11.20 min induction time), n-hexane extract (7.58 min induction time), and water extract (8.26 min induction time) after treatment with 600 ppm DJI doenjang extracts demonstrated longer induction periods than did BHT (6.94 min). These results indicate that DJI doenjang has potential anti-oxidative activity.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.325-333
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• 2007

One bacterium with high proteinase production and spore-forming ability was isolated from korean traditional soybean paste(doenjang). The isolated strain was identified as Bacillus subtilis, based on gram-staining, biochemical properties and l6S rRNA gene sequencing, and designated as B. subtilis DJI. Its growth rate was very fast, and it reached its stationary phase within 9 h, and then started to form spores. Bacterial-koji and doenjang were prepared using B. subtilis DJI. Chemical components of the doenjang were determined after 2 months of aging period: amino nitrogen 507 mg%, crude protein 14.3%, crude fat 4.8% and water 54.9%. The composition of total and free amino acids and their ratios of doenjang were changed during the aging period. Among total amino acids in DJI doenjang, glutamic acid, aspartic acid, leucine and arginine were the major amino acids. The fibrinolytic activities of DJI doenjang and traditional doenjangs were 909.7 units/ml and $363.3{\sim}618.6\;units/ml$, respectively. Flavor compounds of DJI doenjang and traditional doenjang were extracted by SDE(simultaneous steam distillation and extraction), and analyzed by GC/MS; DJI doenjang possessed the typically favorable flavor compounds in traditional korean doenjang, with reduced off-flavor compounds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1699-1706
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• 2009

This study was conducted to investigate the antioxidative effects of chungkukjang fermented using Bacillus subtilis DJI (DJI CJ) in rats fed high cholesterol diet. Sprague-Dawley male rats weighing 185-195 g were divided into 6 groups: normal group (N), high cholesterol group (C), high cholesterol and DJI CJ with no salt group (C-CJN), high cholesterol and DJI CJ added with solar salt group (C-CJS), high cholesterol and DJI CJ added with refined salt group (C-CJR), and high cholesterol and commercial CJ group (C-CCJ). The body weight gain and food intake in all four CJ groups were lower than C group. The serum activities of AST and ALT that were elevated by high cholesterol diet were significantly decreased by CJ supplemented. The hepatic activities of catalase and SOD in C group were increased to 20.59% and 18.72%, respectively, compared with N group, but those of C-CJN, C-CJS, C-CJR, and C-CCJ groups were similar to those of N group. Liver TBARS contents were significantly decreased in all CJ groups, compared with C group. The contents of brain lipofuscin in C-CJN, C-CJS, C-CJR, and C-CCJ groups were remarkably inhibited about 20.86%, 22.06%, 14.73%, and 12.88%, respectively, compared with C group. There were no significant differences among DJI CJ groups in antioxidative effects. According to this study, DJI chungkukjang or commercial chungkukjang seems to protect tissues from oxidative stress by stimulating antioxidative systems in rats fed a high cholesterol diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.8
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• pp.1086-1093
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• 2012

The hypoglycemic and hypolipidemic effects of autoclaved soy flour and DJI chungkukjang powder fermented using Bacillus subtilis DJI were investigated in type 2 diabetic animal models. After a 2-week adaptation period, the diabetic animal model db/db mice were divided into the diabetic control group (D-C group), a diabetic group fed with soybean (D-S group), and a diabetic group fed with DJI chungkukjang (D-CJ group). The body weight gain, food intake, water intake, liver, and adipose tissue weights were not significantly different between the experimental groups. The supplementation of DJI chungkukjang or autoclaved soy flour diet induced a marked reduction of fasting blood glucose, blood glycosylated hemoglobin levels, and glucose levels in the oral glucose tolerance test and AUC for glucose compared with the diabetic control group. However, DJI chungkukjang showed a much stronger antidiabetic effect than unfermented autoclaved soy flour. Serum insulin levels were the same among the groups. The supplementation of DJI chungkukjang or autoclaved soy flour diet also significantly lowered the serum triglyceride, total cholesterol, and LDL-cholesterol levels compared with the control diabetic group, while it elevated the HDL-cholesterol level in the serum. This data suggests that the dietary supplementation of autoclaved soy flour or DJI chungkukjang may be useful in the control of blood glucose in animals with type 2 diabetes.

• 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.

• Journal of Life Science
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• v.20 no.7
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• pp.1134-1142
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• 2010

This study was carried out to investigate the effects of powders of autoclaved soy flour and doenjang fermented using Bacillus subtilis DJI on lipid profiles and antioxidative activities of rats fed a high cholesterol diet. Sprague-Dawley male rats weighing 200~210 g were divided into four groups: normal diet group (N), high cholesterol diet group (HC), autoclaved soy flour and high cholesterol diet group (SHC), and doenjang and high cholesterol diet group (DHC). The serum ALT, AST and ALP activities of the SHC and DHC groups were lower than those of the HC group, but exerted no significant change on serum LDH activity. Serum triglyceride, total cholesterol and LDL-cholesterol levels were markedly decreased by autoclaved soy flour and doenjang administration, while the serum HDL-cholesterol level was higher in groups given autoclaved soy flour and doenjang administration. The GSH-Px and catalase activities in liver elevated by a high cholesterol diet were significantly decreased by autoclaved soy flour and doenjang administration (p<0.05). Liver GSH levels of the SHC and DHC groups were significantly decreased compared to the HC group (p<0.05). Liver TBARS level was significantly decreased in the DHC group fed with doenjang powder compared with those of the HC group (p<0.05). These results suggest that soy flour and doenjang may reduce levels of serum cholesterol and prevent oxidative stress by stimulating antioxidative systems in rats fed a high cholesterol diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.621-629
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• 2012

This study investigated the effect of soybeans, $chungkukjang$, and $doenjang$ on blood glucose and serum lipid profile in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats weighing 205 g were divided into non-diabetic and diabetic groups. The diabetic groups were further subdivided into four experimental groups: a normal group (N), a diabetic control group (STZ-C), a diabetic group fed autoclaved soybean powder (STZ-S), a diabetic group fed $chungkukjang$ powder (STZ-CKJ) and a diabetic group fed $deonjang$ powder (STZ-DJ). Food and water intakes were higher in the diabetic groups than in the N group. The body weight gain and food efficiency ratios were higher in the STZ-S, STZ-CKJ, and STZ-DJ groups than in the STZ-C group, but created no significant changes between the diabetic groups on food intake and body weight gain. The whole blood level at 4 weeks of the STZ-CKJ group was significantly lower than the STZ-C group. Serum glucose levels of the STZ-S, STZ-CKJ, and STZ-DJ groups were significantly lower than the STZ-C group, but there was no significant change in serum insulin levels. The AST and ALP activities in serum were markedly higher in the STZ-C group, but these decreases in relation to diabetes increased in the STZ-S, STZ-CKJ, and STZ-DJ groups. The level of serum triglycerides was lower in the STZ-CKJ and STZ-DJ groups than in the STZ-C group, whereas level of serum HDL-cholesterol was higher in the STZ-CKJ and STZ-DJ groups. Levels of total serum and LDL-cholesterol were higher in the diabetic groups compared with the N group, but significantly decreased in the STZ-S, STZ-CKJ, and STZ-DJ groups compared to the STZ-C group. These results indicate that dietary supplements of soybean, $chungkukjang$ and $doenjang$ may improve blood glucose and lipid metabolism and help prevent or attenuate the progression of diabetes in STZ-induced diabetic rats.