• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.609-617
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• 1998

A microorganism capable of producing high level of extracellular cyclodextrin glucanotransferase(EC 2.4.1.19 ; CGTase) was isolated from Kimchi. 2-O-$\alpha$-D-glucopyranosyl L-ascorbic acid(AA-2G) was synthesized by transglycosylation reaction of CGTase using starch as a donor and L-ascorbic acid as an acceptor. The isolated strain S-6 was identified as Bacillus sp. S-6. The maximal CGTase production was observed in a medium containing 0.5% soluble starch, 1% yeast extract, 1% NaCO3, 0.1% K2HPO4, and 0.02% MgSO4 with initial pH 8.0. The strain was cultured at 37$^{\circ}C$ for 40 hr with reciprocal shaking. Using the culture supernatant as crude enzyme, the optimal pH and temperature of the CGTase activity of this strain were 7.0 and 4$0^{\circ}C$. In the effects of pH and temperature on the stability of the enzyme, the enzyme was stable in the range of pH 6.0~10.0 and up to 45$^{\circ}C$, respectively.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.855-860
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• 2009

Physicochemical properties of starches isolated from 3 new potato cultivars developed by Potato Valley Ltd. were investigated and compared to those of starch isolated from 'Superior' being distributed prominently in Korea. Significant differences were observed in physicochemical properties such as granule size, amylose content, phosphorus content, water binding capacity, swelling power, solubility, and in vitro digestibility of starches from different potato cultivars. Thermal properties were evaluated using differential scanning calorimetry (DSC), and onset gelatinization temperatire ($T_o$), peak temperature ($T_p$), and enthalpies of gelatinization (${\triangle}H$) of different potato cultivars ranged as $58.0{\pm}0.3-61.7{\pm}0.4^{\circ}C,\;63.7{\pm}0.2-$ $66.5{\pm}0.0^{\circ}C$, and $15.6{\pm}0.5-17.0{\pm}0.3$ J/g, respectively. Pasting properties were evaluated using a rapid visco analyzer (RVA), and pasting temperature, peak viscosity, and final viscosity of different potato cultivars ranged as $65.0{\pm}0.1-68.9{\pm}0.1^{\circ}C$, $8,163.7{\pm}196.3-9,035.7{\pm}6.4$ cp, and $4,397.7{\pm}166.7-7,025.0{\pm}271.3$ cp, respectively. Especially, 'Gogu valley' starch showed the highest values in the amylose and phosphorus content among tested potato cultivars and higher water binding capacity, swelling power, and solubility than those of other tested starches. And it also showed high pasting temperature, peak viscosity, trough viscosity, and final viscosity as compared to other tested starches.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.370-378
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• 1989

An Alkalophilic Bacillus circulans that can produce significant amount of cyclodextrin glucanotransferase (CGTase) was newly isolated from soil. The culture filtrate was successively purified by ($NH_4$)$_2$$SO_4$precipitation, DEAE-Sephadex column chromatography, and Sephadex G-100 column chromatography. The enzymatic properties, including molecular weight, optimal pH and temperature, stability, and kinetic parameters, were determined. The cyclodextrin synthesis reaction catalized by the purified CGTase was also studied. The sweet potato and corn starch were found to be the most suitable substrates with 60% conversion to cyclodextrin. The highest conversion was achieved at the CGTase concentration of 900-1,100 units/g of soluble starch. The purified CGTase could also catalize the transglycosylation on stevioside.

• Applied Biological Chemistry
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• v.32 no.4
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• pp.408-415
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• 1989

Twenty-seven strains of starch utilizing yeasts were isolated from 30 samples of ‘Nuruk’, a traditional starter in Korea. These strains were identified as ten species belonging to four genera; Hansenula anomaly (six strains), Hansenula sydowiorum (two strains), Saccharomycopsis fibuligera (four strains), Schwanniomyces occidentalis (two strains), Candida fabianii(two strains), Candida famata(one strain), Candida hydrocarbofumarica (three strains), Candida silvicola (one strain), Candida steatolytica (four strains) and Candida tropicalis (two strains). Saccharomycopsis fibuligera Nu-01, Nu-08, Nu-12 and Nu-27 produced much amylase, and one of these, Saccharomycopsis fibuligera Nu-12 showed the highest amylase activity (16.9 IU/ml). Among the isolates, the strains of Hansenula anomala were exhibited relatively high specific growth rate in the medium used starch as a carbon source, and ethanol fermentation by the strains of Candida hydrocarbofumarica was not observed.

• Korean Journal of Food Science and Technology
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• v.9 no.4
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• pp.277-283
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• 1977

1) Higher yield of red color was observed by the isolated strain (Monascus D-7) than the type cultures in steamed rice medium. 2) In a case of Monascus purbigerus IAM 8004, best yield of color was obtained at Lin's submerged culture medium containing 1% wheat bran, 2% starch and 3% corn meal instead of rice powder as carbon source. However, in a case of isolated strain (M. D-7), good result was shown at 1% rice bran and 2% starch as a source of carbon in Lin's medium. 3) Good yields were obtained from both strains in Nishikawa's medium which was added with 3% defatted soybean flour. 4) There were no significant differences in pigment extractability among solvents. Extracted pigment was stable in wide range of pH and heat, whereas relatively unstable in sunlight. 5) Toxicological study of extracted pigment determined $LD_{50}$ at 0.2539g/20g, when injected in mouse. When injected in to mouse in 25% ethanol solution: considering the toxicity of ethanol, the toxicity of pigment itself is believed to be none.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.226-231
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• 1998

The medium optimization was investigated to maximize the production of fibrinolytic enzyme by Bacillus subtilis KCK-7 isolated from Chungkookjang, which could hydrolyze the fibrin produced through the blood coagulation mechanism in human body. The simultaneous addition of 5% soluble starch and 0.5% cellobiose to the medium as carbon sources resulted in the highest production of the fibrinolytic enzyme. Likewise, the optimized composition of medium appeared to be 0.5% peptone, 0.3% beef extract, 0.5% cellobiose, 5% soluble starch, 2% raw soybean meal and 0.02% Na$_2$HPO$_4$. In addition, the fibrinolytic enzyme production by Bacillus subtilis KCK-7 reached to the maximum level after the cultivation for 48 hr, using the optimized medium.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1904-1915
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• 2019

Resistant starch (RS) is metabolized by gut microbiota and involved in the production of short-chain fatty acids, which are related to a variety of physiological and health effects. Therefore, the availability of RS as a prebiotic is a topic of interest, and research on gut bacteria that can decompose RS is also important. The objectives in this study were 1) to isolate a human gut bacterium having strong degradation activity on non-gelatinized RS, 2) to characterize its RS-degrading characteristics, and 3) to investigate its probiotic effects, including a growth stimulation effect on other gut bacteria and an immunomodulatory effect. Bifidobacterium adolescentis P2P3 showing very strong RS granule utilization activity was isolated. It can attach to RS granules and form them into clusters. It also utilizes high-amylose corn starch granules up to 63.3%, and efficiently decomposes other various types of commercial RS without gelatinization. In a coculture experiment, Bacteroides thetaiotaomicron ATCC 29148, isolated from human feces, was able to grow using carbon sources generated from RS granules by B. adolescentis P2P3. In addition, B. adolescentis P2P3 demonstrated the ability to stimulate secretion of Th1 type cytokines from mouse macrophages in vitro that was not shown in other B. adolescentis. These results suggested that B. adolescentis P2P3 is a useful probiotic candidate, having immunomodulatory activity as well as the ability to feed other gut bacteria using RS as a prebiotic.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.385-390
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• 2010

Bacillus licheniformis fermenting soybean product with highest score in consumer acceptance had been isolated from homemade Cheongkookjang. In order to develop the medium composition, effects of ingredients including nitrogen sources, carbon sources, metal ions and phosphate were examined for protease production of the isolate. Potato starch increased the protease productivity, while glucose repressed it. Yeast extract was the most effective nitrogen source for enzyme production. The calcium was found to increase protease activity slightly while cell growth and enzyme production was completely inhibited by divalent ions such as $Zn^{2+}$, $Cu^{2+}$ and $Co^{2+}$. The maximum protease productivity was reached approximately 800 unit/mL in the optimized medium consisting of potato starch (1.5%), yeast extract (1.5%), $CaCl_2$(0.7%), $K_2HPO_4$(0.03%) and $KH_2PO_4$(0.03%). The protease activity of culture filtrate was gradually decreased after incubation for 28 h.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.393-397
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• 2004

Rice was steeped at elevated temperatures of $40,\;50,\;or\;60^{\circ}C$ for 2 hr, and physicochemical properties of starches isolated from wet-milled rice flour were investigated. Steeping at elevated temperatures slightly decreased lightness of rice starch, while increased yellowness and redness. Average granule size of rice starch was decreased by steeping treatment. Swelling power and solubility increased as temperature increased. Starch from rice steeped at $40^{\circ}C$ displayed highest swelling power and solubility. Differential scanning calorimetry data of starch obtained from steeped rice at $60^{\circ}C$ showed increased onset and peak temperatures, with narrower gelatinization temperature range, suggesting partial annealing effect. Pasting properties of starch measured by Rapid Visco-Analyzer indicated increased peak viscosity due to rice steeping at $40^{\circ}C$. Peak and breakdown viscosities decreased at $50\;and\;60^{\circ}C$, whereas setback and final viscosities increased.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.528-535
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• 1989

Starches isolated from Seipoong and Daeji potato were classified into small and large granules. The starch granule size for Seipoong and Daeji was in the range of $10-85\;{\mu}m$ and $13-90\;{\mu}m$, respectively. Seipoong starch contained more large granules $(>41\;{\mu}m)$ while Daeji starch had more small granules $(<30\;{\mu}m)$. There was no difference in water-binding capacity both between two starches and among granule sizes. Amylose content for toro starches was the same but was higher in large starch granules than small ones. Swelling powder at $80^{\circ}C$ for parent starches was essentially the same but small starch granules had much higher swelling powder than large ones. The large starch granules for Daeji showed higher peak viscosity by amylograph than small starch granules. No such difference was observed for Seipoong starch. The gelatinization temperature range of small starch granules was wider than that of large ones, but gelatinization enthalpy was the same between large and small starch granules. The starches regardless granule sizes were completely gelatinized at $70^{\circ}C$.