• Proceedings of the Korean Nutrition Society Conference
• /
• 2000.06a
• /
• pp.122-122
• /
• 2000

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

• Journal of Microbiology and Biotechnology
• /
• v.25 no.4
• /
• pp.469-478
• /
• 2015

In spite of the reported probiotic effects, Bifidobacterium bifidum BGN4 (BGN4) showed no βglucosidase activity and failed to biotransform isoflavone glucosides into the more bioactive aglycones during soy milk fermentation. To develop an isoflavone-biotransforming BGN4, we constructed the recombinant B. bifidum BGN4 strain (B919G) by cloning the structural β-glucosidase gene from B. lactis AD011 (AD011) using the expression vector with the constitutively active promoter 919 from BGN4. As a result, B919G highly expressed β-glucosidase and showed higher β-glucosidase activity and heat stability than the source strain of the β-glucosidase gene, AD011. The biotransformation of daidzin and genistin compounds using the crude enzyme extract from B919G was completed within 4 h, and the bioconversion of daidzin and genistin in soy milk during fermentation with B919G also occurred within 6 h, which was much faster and higher than with AD011. The incorporation of this β-glucosidase-producing Bifidobacterium strain in soy milk could lead to the production of fermented soy milk with an elevated amount of bioavailable forms of isoflavones as well as to the indigenous probiotic effects of the Bifidobacterium strain.

• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.522-526
• /
• 1997

Soy isoflavones could be recovered with adsorption resin column chromatography from soybean cooking water produced during soymilk or tofu manufacturing process. The main isoflavones in the soybean cooking water were genistin and daidzin, and their concentration was $0.083{\pm}0.019$ and $0.11{\pm}0.017\;mM$, respectively. Their aglycones were not detected. pH of soybean cooking water was critical in this chromatographic process and the recovery of isoflavones, both genistin and daidzin, was maximum at pH 4.0. Adsorption of genistin on the resin was stronger than that of daidzin. Elution rate and height/diameter ratio also affected the recovery yield. Under the optimal conditions, about 85% of genistin and 70% of daidzin could be isolated from soybean cooking water. Soy saponins were also recovered with isoflavones.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.1
• /
• pp.27-35
• /
• 2005

This study was performed to determine the effect of three different concentrations of soy-isoflavones on excretions through urine and feces in either sham-operated or ovariectomized female rats. Seventy-two 16-week old Sprague-Dawley rats underwent sham operation or bilateral ovariectomy. They were provided diets containing different levels of soy isoflavones for 6 weeks: 50 ppm (low isoflavone intake; LI), 250 ppm (medium isoflavone intake; MI) and 500 ppm (high isoflavone intake; HI). The subsequent fecal and urinary excretions of daidzein and genistein were then measured. In the sham operated rats, body weight gains and food efficiency ratio of the MI and HI groups were significantly lower than control group, while food intake was not different. However, there was no significant difference in ovariectomized rats. The fecal excretion of daidzein was significantly higher in the HI group than the LI and MI groups, and that of genistein increased as dietary isoflavone intakes increased in both the sham operation and ovariectomy. The reverse tendency of fecal recovery was shown with dietary isoflavone dose only in genistein among ovariectomized rats. When dietary isoflavones were increased from 50 ppm to 500 ppm, the amounts of daidzein and genistein in the urine increased dose-dependently. The higher intakes of isoflavones leaded to lower recovery rates of daidzein and genistein in the urine in the sham-operated rats but not in the ovariectomized rats. The urinary recovery was significantly higher in the LI group than the MI and HI groups in the sham-operated rats. The excreted amounts and recovery of the two isoflavones in the urine were higher in the sham operated groups than in the ovariectomized groups, which implied an increased bioavailability of isoflavones by ovariectomy. Therefore, the results suggest that a more efficient use of soy isoflavones in ovariectomized conditions may occur, which indicates that a higher dose of soy isoflavones is necessary for the postmenopausal states.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.246.2-247
• /
• 2003

Lately, soybeans have received considerable public attention for their potential roles in the prevention of the chronic diseases. Epidemiologic study showed that Asian countries have significant health benefits because of the high contents of the isoflavones in their traditional diets(soybean-rich diet). This study was carried out to determine pharmacokinetic parameters of isoflavone in Korean woman. Pharmacokinetic study of three soy products(isogen, soymilk, and fermented soybean) with different ration of aglycone/glucoside in 26 healthy female volunteers(20-30 years of age) was performed. (omitted)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.2
• /
• pp.135-141
• /
• 2001

Recently, the consumption of soy products has been associated with low rates of hormone-dependent and hormone-independent cancers. Asians, who consume $20{\sim}50times$ more soy per capita than Americans, have lower incidence and death rates from breast and prostate cancer. Because soy contains the isoflavones genistein and daidzein (present as their glycosidic conjugates) at mg/g concentrations, it has been suggested that isoflavones might be acting as natural chemopreventive agents. During the 1980s several groups of investigators carried out experiments to test the effectiveness of soy in the diet in animal models of cancer. These studies reported a protective effect of soy; none showed that soy increased cancer risk. Genistein was shown to inhibit the growth of a wide variety of tumor cell types in culture. The purpose of this study was to evaluate the effects of genistein on the carcinogenesis induced by topical application of 0.5% 9, 10-dimethyl 1,2-benzanthracene (DMBA) on the hamster buccal pouch. 48 syrian hamsters were employed in this study, divided into experimental group and control. 24 animals (DMBA topical application group) had the right buccal pouch painted 3times weekly with 0.5% DMBA in mineral oil, 24 animals (genistein group) were supplied with 0.1mg genistein with DMBA topical application. 3 animals in the experimental group and control were sacrificed at serially each other week after experiments. Their buccal pouches were removed and routinely processed for microscopic examination. The results were as follows: 1. In DMBA topical application and genistein group, they showed carcinogenesis as time goes by experimental stage. 2. Genistein group was retarded in carcinogenesis related to the acanthosis, hyperkeratosis, epithelial dysplasia. 3. p53 immunohistochemical study showed that the p53 protein of genistein group was less expressed than that of the control group. Thus, it seems that genistein has chemopreventive effect on the carcinogenesis in the oral cavity, but further study is required to elucidate the anticancer mechanism of genistein.

• Proceedings of the KSCN Conference
• /
• 2000.11a
• /
• pp.86-86
• /
• 2000

• Nutrition Research and Practice
• /
• v.2 no.2
• /
• pp.55-61
• /
• 2008

We investigated the combinatorial effects of different doses of dietary soy isoflavones (SI) and fructooligosaccharide (FOS) in a rat model of colon cancer. We hypothesized that increased bioavailability of SI metabolites due to dietary FOS may increase production of bioactive equol and affect colon carcinogenesis in a dose-dependent manner. Sprague-Dawley male rats were injected with 12-dimethylhydrazine (DMH) and were providec experimental diets that contained 0, 10, 50, 150, or 500 mg SI per kg of diet and 6% FOS for 12 weeks. The number of aberrant crypt foci (ACF) and the expression of cyclooxygenase-2 (COX-2) in colonic tissues were significantly decreased in the 6% FOS-fed groups compared to the control group. Gut transit time and fecal pH were significantly lower, and fecal concentrations of bifidobacteria were increased with 6% FOS. However, dietary SI supplementation in combination with 6% dietary FOS did not affect ACF formation or COX-2 expression. Plasma equol concentrations were dose-dependently increased by supplementation of SI up to 500 mg/kg of diet. In conclusion, SI supplementation up to 500 mg/kg of diet appeared to have no additive beneficial effects in rats with chemically-induced colon cancer that were fed 6% FOS, although plasma equol was dose-dependently increased.

• Food Science and Biotechnology
• /
• v.17 no.2
• /
• pp.442-445
• /
• 2008

Meju, a major ingredient of doenjang which is a popular Korean traditional fermented soyfood, was manufactured by fermenting steamed soybeans in natural environment in which steamed soy was exposed to airborne microorganism, in particular, fungi. Total isoflavone content was reduced from 1,849 mg/kg of cooked soy to 816 mg/kg of meju at the $90^{th}$ day of fermentation. Total glycosides and aglycones of isoflavones in meju were 1,827 and 22 mg/kg at 0 day and changed into 487 and 329 mg/kg at the 90th day of fermentation, respectively. Meanwhile, the ratio of glycosides to aglycones of isoflavones was not changed during aging of doenjang but remained relatively constant with 592 and 644 mg/kg aglycones at the 0 and $160^{th}$ day, respectively. When cooked soy was fermented with Aspergillus oryzae and Aspergillus flavus, isoflavone profiles were significantly different from each other while A. oryzae caused more extensive metabolism of isoflavones than A. flavus.