• Food Science and Biotechnology
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• v.16 no.1
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• pp.83-89
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• 2007

In our study, lactic acid bacteria (LAB)-fermented whey solutions were applied in the soybean soaking process to minimize bacterial contamination and to enrich the biologically functional components of isoflavone and $\gamma$-aminobutyric acid (GABA). Among the 11 LAB tested, Bifidobacteria infantis and a mixed culture (Lactobacillus acidophilus, Bifidobacteria lactis, and Streptococcus thermophilus; ABT-3) displaying the greatest $\beta$-glucosidase activity were selected to produce improved biologically functional soybean preparations. In the soybean soaking processing (without water spraying), the LAB-cultured 10% whey solution was used to soak and to ferment the soybeans and the fermented soybeans were finally dried by heat-blowing at $55^{\circ}C$. The processing conditions used in this study demonstrated that the final soybean product had a reduced contamination by aerobic and coliform bacteria, compared to raw soybeans, likely due to the decrease in pH during LAB fermentation. The aglycone content of the isoflavone increased up to 44.6 mg per 100 g of dried soybean by the processing method, or approximately 8-9 times as much as their initial content. The GABA contents in the processed samples increased as the processing time of soaking-fermentation proceeded as well. The soybean sample that fermented by ABT-3 culture for 24 hr showed the greatest increase in GABA content (23.95 to 97.79 mg/100 g), probably as a result of the activity of glutamate decarboxylases (GAD) released from the soybean or produced by LAB during the soaking process.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.734-739
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• 2007

This study was conducted to observe the quality characteristics of cheonggukjang fermented with new small-seed soybeans ('Agakong') according to the degree of germination of the raw soybeans. The sprouting rate was $8.6{\pm}5.6%$ after 12 hr of germination, but at 24 hr it increased rapidly to $85.4{\pm}4.7%$. We confirmed that the total isoflavone content immediately after soaking was 273.9 mg%, which was at least 3 times greater than for common soybeans; content increased at the start of germination, and increased to 338.4 mg% by 24 hr of germination, but then decreased. The quantity of viscous substance of the cheonggukjang increased in proportion to the degree of germination of the raw soybeans. The levels of amino acids in the cheonggukjang made from non-germinated soybeans, and soybeans germinated 48 hr, were 12.45 and 10.06%, respectively. The isoflavone levels in the cheonggukjang were determined by the degree of germination of the raw soybeans. There were no significant differences between the odor, sweet taste, savory taste, bitter taste, and overall acceptability of the cheonggukjang with different germination times of 0 to 36 hr.

• Korean journal of food and cookery science
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• v.12 no.4
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• pp.527-534
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• 1996

enistein (G), and daidzein (D), the major isoflavones, were analyzed in 14 varieties of Korean soybean and various processed soybean products by using high performance liquid chromatography. Isoflavone contents (G+D) were greatly variable among varieties ranged from 308.2 $\mu\textrm{g}$/g to 1,134.2 $\mu\textrm{g}$/g and highest in Danyopkong and Jinpumkong. Among hypocotyl, cotyledon and hull of soybean the concentration of the isoflavone (G+D) in the hypocotyl was highest ranged from 2,971.7 $\mu\textrm{g}$/g to 5,704.9 $\mu\textrm{g}$/g. The distributions of genistein and daidzein were also different in hypocotyl, cotyledon and hull. Higher ratio of daidzein to genistein (D/G) was found in the hypocotyl (4-12) compared to cotyledon and hull (0.1-4). Isoflavone (G+D) contents of soymilks (Sinpaldal#2, Eunhakong) prepared at 16 hour hydration were decreased to 1.1-1.2 times compared with that at 8 hour hydration. Commercial soymilks contained much lower isoflavone (G+D) than laboratory soymilks. Soybean curd (Eunhakong) prepared with MgCl$_2$ showed higher isoflavone (G+D) contents than that with CaSO$_4$. But these values of two different soybean curds made at laboratory were similar to those of 3 commercial curds. The concentration of the isoflavones in soybean sprout separated with 3 parts revealed highest in the head and lowest in the stem. Compared with non-fermented soybean foods the fermented soybean produfts, Kochujang and soybean paste, Duen Jang, showed very low contents of isoflavone (G+D),2.8-3.0 $\mu\textrm{g}$/ｇ, 35.9-63.6 $\mu\textrm{g}$/ｇrespectively.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.172-175
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• 2008

Two new fermentation products were separated from cheonggukjang by high performance liquid chromatography (HPLC) and tentatively identified as succinyl daidzin and succinyl genistin by HPLC-mass spectrometry (MS). Both succinyl daidzin and succinyl genistin were detected in all 4 commercially available and one laboratory prepared cheonggukjang and 1 commercially available natto. However, these compounds were not detected in commercially available 4 home-made and 4 factory-produced doenjang. Peak areas of succinyl genistin were about 1.95-2.45 times higher than those of succinyl daidzin in cheonggukjang, which may be due to the higher concentration of genistin derivatives than daidzin derivatives in soybeans. This is the first report on the succinyl derivatives as isoflavone metabolites from cheonggukjang and these 2 isoflavone derivatives could be characteristic indicators for cheonggukjang.

• Journal of Microbiology
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• v.45 no.3
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• pp.256-261
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• 2007

Apoptosis is a step of the cell cycle which is important in the regulation of immune cell populations. Chungkookjang is a Korean traditional fermented soybean containing microorganisms, enzymes, and bioactive compounds which was used in the treatment of mouse spleen as well as thymus cells (CH1-fermented soybean containing barley, wormwood, and sea tangle; CH2-fermented soybean) and was found to exhibit substantially reduced small DNA fragmentation. An MTT assay showed that the treatment of CH1 and CH2 into the mouse splenocytes and thymocytes sharply increased their survival. Moreover, a FACS analysis also showed that CH1 and CH2 are effective at suppressing the apoptosis of splenocytes and thymocytes. The fermented soybean isoflavone concentrations, which are implicated in lowering breast and prostate cancers, lowering the risk of cardiovascular diseases, and improving bone health, were determined using Capillary Electrophoresis-Electrochemical Detection (CE-ED). The amount of Daidzein in fermented soybean significantly increased by 44-fold dramatically, compared with those in unfermented soybean. In this study, we demonstrated that ethanol extracts of Chungkookjang promote the survival of the mouse spleen and thymus cells in culture by suppressing their apoptotic death. Future studies should investigate which genes are related to apoptosis of the immune cells.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.539-543
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• 2014

BACKGROUND/OBJECTIVES: Soy isoflavones are structurally similar to estrogen and bind to estrogen receptors, suggesting that they exhibit estrogenic activities; therefore, they are referred to as phytoestrogens. Fermentation may affect the bioavailability of isoflavones altering soy isoflavone glycosides in the form of aglycones. Thus, this study investigated the effects of fermented soybeans by Rhizopus oligosporus on bone metabolism in both young rats as a pilot test and in ovariectomized (ovx) old rats as a model of menopause. MATERIALS/METHODS: In the pilot test, a total of 24 seven-week-old female Sprague-Dawley (SD) rats were fed one of three diets for a period of four weeks: casein, unfermented soybean product, or fermented soybean product by R. oligosporus. In the ovx rat model, 20-week-old SD rats weighing 260-290 g underwent either sham-operation (n = 10) or bilateral ovariectomy (n = 30) and were then fed the AIN-93M diet for one week. Thereafter, rats were fed sham-casein, ovx-casein, ovx-soybean, or ovx-fermented soybean diet for five weeks. After decapitation, femoral bones were isolated and preserved in 9% formalin for assessment of bone mineral density (BMD), bone mineral content (BMC), and bone-breaking strength (BBS). RESULTS: Ovx rats showed significantly increased weight gain and decreased uterine wet weight. Of particular interest, ovx rats fed fermented soybeans showed increased uterine wet weights compared to control rats. Fermented soybean diet caused a significant increase in plasma 17-${\beta}$ estradiol concentrations in young rats, and 17-${\beta}$ estradiol levels were enhanced in ovx rats to match those of sham-operated ones. Significantly lower femoral BMD and BMC were observed in ovx rats compared to sham-operated controls, whereas bone areas did not differ statistically among the groups. In addition, BBS tended to be increased in ovx rats fed soybeans and fermented soybeans. CONCLUSIONS: Supplementation of fermented soybeans could have preventive and therapeutic effects against osteoporosis in postmenopausal women.

• Korean journal of food and cookery science
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• v.23 no.4 s.100
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• pp.537-550
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• 2007

In a previous study, isoflavones showed prominent physiological effects on diabetes, hyperlipemia, and alcoholic hepatotoxicity. The purpose of this study was to develop isoflavone-rich bean sprout- and isoflavone extract-containing foods, to improve symptoms of diabetes and hyperlipemia. The foods employed were yogurt, bread, and cookies. Through sensory evaluations, the ingredient amounts were determined. In the sensory evaluations of the yogurt and bread, overall taste scores decreased with increasing amounts of bean sprout powder. However, for the cookies, the overall taste score increased with an increasing amount of bean sprout powder, and the addition of isoflavones had no influence on flavor. The results indicated the following ingredient levels for ultimate product development. For the yogurt, 100 mL of low fat milk was fermented at $50^{\circ}C$ for 36 hr, and mixed with 0.5 g of roasted bean sprout powder and 31 mg of isoflavone extract. For the bread, bean sprout powder was added to wheat flour at a replacement level of 10%, which was mixed with 12 g of butter and 124 mg of isoflavone extract for 200 g of dough. For the cookies, the bean sprout powder was added to wheat flour at a replacement level of 60%, and then mixed with 15 g of butter and 124 mg of isoflavone extract for 100 g of dough. The total isoflavone contents of the yogurt, bread, and cookies were 14.35 mg/100 mL, 38.24 mg/100 g, and 190.00 mg/100 g, respectively.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.160-167
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• 2013

In order to investigate changes in quality and enzyme activity during Chungkookjang fermentation, germinated- and nongerminated yellow soybeans were fermented by Bacillus subtilis and traditional methods. When the soybean was soaked for 6 h and then watered for 4 days with 2 h-interval at $25^{\circ}C$, the highest germination rate was obtained. The germinated soybeans had a higher total isoflavone ($988.4{\mu}g/g$) than that of the nongerminated soybeans ($859.5{\mu}g/g$). Amino type nitrogen contents, protease and amylase activities were higher in germinated soybean Chungkookjang, which was fermented with B. subtilis, than nongerminated soybean Chungkookjang, which was fermented with B. subtilis and traditional methods. Reducing sugar and amino type nitrogen contents, the number of viable cells and protease and amylase activities, were higher for Chungkookjang fermented with B. subtilis, than Chungkookjang fermented by traditional methods. ALP and SOD activities in the Chungkookjang diet group were considerably higher than in the control group. AST activity in the germinated soybean Chungkookjang diet group was higher than in the nongerminated soybean Chungkookjang diet group. In conclusion, it is suggested that Chungkookjang prepared with germinated soybeans using B. subtilis D7 could be practically used as a functional product.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.1046-1050
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• 2009

Our previous study showed that isoflavone profile of soybean undergoes a significant change during cheonggukjang preparation. In particular, the content of metabolite(s) with similar retention time to glycitein under the high performance liquid chromatography (HPLC) condition was significantly increased while the levels of genistein and its derivatives were notably lowered. Therefore, we hypothesized that genistein and its derivatives might be converted to genistein glucosides with similar elution time to glycitein. Our current data suggest that genistein and its derivatives are extensively metabolized into various compounds including genistein glycosides, but not glycitein or its derivatives, by Bacillus species isolated from traditional cheonggukjang. Some of daidzein was also converted into a derivative with shorter retention time by Bacillus amyloliquefaciens 51 and 86-1 but not by Bacillus subtilis 3-5 and 3-17. As metabolism of soy isoflavones, major health-promoting components in soy products, is widely variable depending upon Bacillus species, it is essential to select microorganism that minimizes the breakdown or modification of soy isoflavones in the process of fermented soy product manufacture.