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Kim M.-H.,Chonbuk National University | Kim S.-Y.,Chonbuk National University | Ko J.-M.,NICS | Jeong D.-Y.,Sunchang Research Center for Fermentation Microbes | Kim Y.-S.,Chonbuk National University
Food Science and Biotechnology | Year: 2012

To select proper soybean cultivars for producing functional cheonggukjang, a comparison was made of the physiological activities of different cheonggukjang prepared with 30 different soybean cultivars. The isoflavone content was highest in the cheonggukjang made from 'Daepung' soybeans at 208. 75 mg%. In general, the contents of glycone types (and derivatives) of isoflavone, specifically daidzin, glycitin, genistin, and malonylgenistin, were higher than that of aglycone types. The polyphenol contents ranged from 30. 62 to 80. 32 mg%. The DPPH radical scavenging activity and superoxide dismutase (SOD)-like activity of the cheonggukjang made from yellow soybeans had a higher activity than those of black soybeans. Although there are no consistent tendencies in the functional activity of cheonggukjang according to soybean color and size, the antioxidative activity is highest in the cheonggukjang made of yellow soybeans. Additionally, the fibrinolytic and inhibitory activities against angiotensin I-converting enzyme are highest in the cheonggukjang made of black soybeans. From these results, it can be concluded that the DPPH free radical scavenging activity and SOD-like activity in cheonggukjang depends on the phenolic compound content in soybean. © 2012 The Korean Society of Food Science and Technology and Springer Netherlands. Source

Song Y.-R.,Chonbuk National University | Jeong D.-Y.,Sunchang Research Center for Fermentation Microbes | Cha Y.-S.,Chonbuk National University | Baik S.-H.,Chonbuk National University
Journal of Microbiology and Biotechnology | Year: 2013

This work is aimed to increase knowledge of the functional exopolysaccharide (EPS) from lactic acid bacteria (LAB) in makgeolli, a Korean fermented rice wine. Among LAB strains isolated from makgeolli, strain M76 was selected as a functional strain producing a bioactive EPS, based on its antioxidative activity on the DPPH radical. The 16S rRNA gene sequencing analysis showed a high sequence similarity (99.0%) with P. acidilactici, but had different biochemical properties with the already known P. acidilactici type strains in the aspect of carbohydrates utilization. The obtained P. acidilactici M76 produced a soluble EPS above 2 g/l. One-step chromatography using gel filtration after ethanol precipitation from the supernatant of P. acidilactici M76 was enough to obtain purified EPS with a single peak, showing a molecular mass of approximately 67 kDa. Componential and structural analyses of EPS by TLC, HPLC, and FT-IR indicated that the EPS is a glucan, consisting of glucose units. The purified EPS had antioxidant activity on the DPPH radical of 45.8% at a concentration of 1 mg/ml. The purified EPS also showed proliferative effect on the pancreatic RIN-m5F cell line and remarkable protection activity on alloxan-induced cytotoxicity. This potent antioxidant and antidiabetic EPS by LAB in makgeolli may contribute to understanding the functionality of makgeolli. Source

Song Y.-R.,Chonbuk National University | Jeong D.-Y.,Sunchang Research Center for Fermentation Microbes | Baik S.-H.,Chonbuk National University
Food Science and Biotechnology | Year: 2013

A strain producing exopolysaccharide (EPS) with strong hydroxyradical scavenging activity and antityrosinase activity has been isolated previously. However, the EPS production rate of the strain (7. 3 g/L) was relatively low to utilize it at the industrial level. Therefore, in this study, optimal medium and fermentation conditions were examined to enhance EPS production by Bacillus licheniformis KS-17. Maximum EPS production was obtained in medium with 125 g/L sucrose, 30 g/L ammonium sulfate, and 10 mM calcium chloride without a phosphate source at 37°C for 5 days with the initial pH adjusted to 8. 5. Under optimal culture conditions, EPS was produced at up to 27. 2 (at 5 days) vs. 12. 0 g/L (at 7 days under basal conditions), which was 2. 3 times greater and in a shorter time than the production yield possible without optimizing conditions. © 2013 The Korean Society of Food Science and Technology and Springer Science+Business Media Dordrecht. Source

Song Y.-R.,Chonbuk National University | Kim Y.-E.,Chonbuk National University | Kim J.-H.,Chonbuk National University | Song N.-E.,Chonbuk National University | And 2 more authors.
Food Science and Biotechnology | Year: 2011

Fermented sugar-soaked black soybean snacks (FSBSS) were prepared using optimized conditions at 2 times sugar soaking process to give a desirable form and texture after fermentation with Lactobacillus plantarum (LP) and Bacillus subtilis (BS) for 48 h. The prepared FSBSS showed higher total polyphenol and flavonoid contents than an unfermented (NF) sample; total isoflavone content increased approximately 31 and 17% (LP and BS, respectively), as compared to NF. γ-Aminobutyric acid was also contributed by LP and BS, indicating significantly higher contents of 16. 9 and 21. 6 mg/g (LP and BS, respectively) compared to NF (15. 2 mg/g). Moreover, the FSBSS showed antioxidant activities on DPPH, superoxide, and hydroxyl radicals as compared to NF. Based on the results, the newly developed FSBSS using solid-fermentation indicate a useful and convenient way to replace traditional soybean products from the standpoint that also provides an easy means to supply high nutritive and functional properties. © 2011 The Korean Society of Food Science and Technology and Springer Netherlands. Source

Gwon H.-J.,Korea Atomic Energy Research Institute | Yoshioka H.,Chiba Institute of Technology | Song N.-E.,Chonbuk National University | Kim J.-H.,Chonbuk National University | And 3 more authors.
Preparative Biochemistry and Biotechnology | Year: 2012

This study examined the efficient production and optimal separation procedures for pure L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) from a mixture of diastereomers synthesized by whole-cell aldol condensation reaction, harboring diastereoselectivity-enhanced L-threonine aldolase in Escherichia coli JM109. The addition of the reducing agent sodium sulfite was found to stimulate the production of L-threo-DOPS without affecting the diastereoselectivity ratio, especially at the 50mM concentration. The optimal pH for diastereoselective synthesis was 6.5. The addition of Triton X-100 also strongly affected the synthesis yield, showing the highest conversion yield at a 0.75% concentration; however, the diastereoselectivity of the L-threonine aldolase was not affected. Lowering the temperature to 10C did not significantly affect the diastereoselectiviy without affecting the synthesis rate. At the optimized conditions, a mixture of L-threo-DOPS and L-erythro-DOPS was synthesized by diastereoselectivity-enhanced L-threonine aldolase from E. coli in a continuous process for 100hr, yielding an average of 4.0mg/mL of L-threo-DOPS and 60% diastereoselectivity (de), and was subjected to two steps of ion exchange chromatography. The optimum separation conditions for the resin and solvent were evaluated in which it was found that a two-step process with the ion-exchange resin Dowex 50W8 and activated carbon by washing with 0.5 N acetic acid was sufficient to separate the L-threo-DOPS. By using two-step ion-exchange chromatography, synthesized high-purity L-threo-DOPS of up to 100% was purified with a yield of 71%. The remaining substrates, glycine and 3,4- dihydroxybenzaldehyde, were recovered successfully with a yield of 71.2%. Our results indicate this potential procedure as an economical purification process for the synthesis and purification of important L-threo-DOPS at the pharmaceutical level. © 2012 Taylor and Francis Group, LLC. Source

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