• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.73-78
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• 1992

- Enzymatic synthesis of L-tryptophan(Trp) using E. coli tryptophanase has been investigated. In order to reduce the substrate inhibition by indole and to increase the product yield of L-tryptophan three different approaches have been made in this work. First, indole was intermittently fed to the reaction mixture in order to control the indole concentration at lower level. When 15 mM of indole was used as a total amount of substrate, conversion yield of 80% has been obtained with intermittent feeding while only 20% of indole was converted into L-tryptophan by conventional batch operation, The second method employed in this work was the use of cyclohexane-phosphate buffer organic two-phase system. In this system, indole was mainly partitioned into the organic-solvent phase and therefore substrate inhibition was expected to be reduced. L-Tryptophan production in organic two-phase system was, however, unexpectedly lower than that obtained in aqueous buffer solution. As a third method cyclodextrins have been added to the aqueous reaction mixture. It was found that the addition of $\beta$-cyclodextrin enhanced the tryptophan synthesis noticeably while $\alpha$-cycfodextrin showed little effect on tryptophan production.

• Journal of Pharmaceutical Investigation
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• v.27 no.1
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• pp.29-38
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• 1997

Precipitation was formed during the preparation of decoction from a mixture of Scutellariae Radix and Coptidis Rhizoma. Baicalin and berberine were identified in this coprecipitated product (CPP) and these components were the active ingredients of two herbal medicine. We extracted respectively crude baicalin and berberine in Scutellariae Radix and Coptidis Rhizoma and prepared coprecipitate of crude baicalin-berberine. To increase the stability and bioavailability of coprecipitate of crude baicalin-berberine(CBB), which is slightly soluble drug, its inclusion complex was prepared and studied in this experiment. Inclusion complex of CBB with ${\beta}-cyclodextrin(CBB-{\beta}-CD)$ was prepared by freeze drying method and its characteristics were ascertained by means of solubility test, differential thermal analysis(DTA) and scanning electron microscope(SEM). The type of $CBB-{\beta}-CD$ is classified as $A_L-type$ on phase solubility diagram, and the stoichiometric ratio of CBB(baicalin in CBB) : ${\beta}-CD$ complex is 1:1 and formation constant is 151 $M^-1$. The solubility, dissolution, in situ absorption and serum concentration of $CBB-{\beta}-CD$ were significantly increased when compared to CBB. Therefore enhanced bioavailability of CBB by inclusion complexation with ${\beta}-cyclodextrin$ might be useful for dosage form design of active ingredients of two herbal medicine.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.509-514
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• 2009

The effectiveness of a technique for binding rice-washed solution with trimethylamine (TMA) was investigated in this study. The mixtures of TMA and rice-washed solution were quantified using an electronic nose based on the mass spectrometer. After 7 min of reaction in a model system, the binding of TMA to the rice-washed solution was detected. As the concentration of rice-washed solution increased, the levels of TMA detected in the headspace decreased, thereby indicating an increase in the binding of TMA to the rice-washed solution. The binding effect of the rice-washed solution was comparable to those of starch, ${\alpha}$-cyclodextrin, or amylose, and superior to that of flour. The results of this study demonstrate the potential for reduction of off-flavors using the rice-washed solution.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.103-108
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• 1998

A hydrophobic substrate triolein was hydrolyzed by lipase in a mono-phase reaction system containing cyclodextrin(CD) as emulsifier. The triolein was transformation to an emulsion-like state in the CD containing reaction system in contrast to the oil-droplet like state without CD due to the formation of an inclusion complex between the lipids and CDs. The hydyrolysis reaction increased substantially in the CD containing reaction system, and the optimum reaction conditions including the amount of lipase, ${\beta}$-CD concentration, and mixing ratio of triolein and ${\beta}$-CD, were determined. The performance of the enzyme reaction in a mono-phase reaction system was compared with that of a two-phase reaction system which used water immiscible hexane as the organic solvent. The role of a CD in the mono-phase reaction system was elucidated by comparing the degree of the inclusion complex formation with triolein and oleic acid, Km and Vmax values, and product inhibition by oleic aicd in aqueous and CD containing reaction systems. The resulting enhanced reaction seems to be caused by two phenomena; the increased accessibility of lipase to triolein and reduced product inhibition by oleic acid through the formation of an inclusion complex.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2487-2493
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• 2014

Dimeric ${\beta}$-cyclodextrin linked by a thioether bridge was synthesized from a reaction of mono-6-iodo-6-deoxy-${\beta}$-cyclodextrin with sodium sulfide, and the structure was analyzed using nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The effects of thioether-bridged dimeric ${\beta}$-CD on the aqueous solubility of flavonols (myricetin, quercetin, and kaempferol) were investigated by ultraviolet-visible spectroscopy. The aqueous solubility of myricetin, quercetin, and kaempferol were enhanced 33.6-, 12.4-, and 10.5-fold following the addition of 9 mM of thioether-bridged dimeric ${\beta}$-CD. In comparison, the aqueous solubility of myricetin, quercetin, and kaempferol were enhanced 5.4-, 3.3-, and 2.7-fold using the same concentration of monomeric ${\beta}$-cyclodextrin. Furthermore, the formation of flavonol/thioether-bridged dimeric ${\beta}$-CD inclusion complexes was confirmed with nuclear magnetic resonance, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. The results showed that the nature of the complexes significantly differed from that of free flavonols. Herein, we suggest that the thioether-bridged dimeric ${\beta}$-CD can act as an effective complexing agent for flavonols.

• YAKHAK HOEJI
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• v.37 no.3
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• pp.216-227
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• 1993

Complex formations of practically insoluble antelmintic drugs such as mebendazole (MBZ), albendazole (ABZ) and flubendazole (FBZ) with dimethyl-$\beta$-cyclodextrin (DM-$\beta$-CyD) and 2-hydroxypropyl-$\beta$-cyclodextrin (HP-$\beta$-CyD) together with $\alpha$-, $\beta$- and $\gamma$-cyclodextrins(CyDs) in duffered solutions were investigated by solubility method. $A_{L}$ type phase solubility diagrams were obtained in all cases except for the complexation (B$_{s}$, type) of FBZ with $\gamma$-CyD. The highest stability constants were obtained with DM-$\beta$-CyD, followed by $\alpha$-CyD > $\beta$-CyD > HP-$\beta$-CyD > $\gamma$-CyD for ABZ, and HP-$\beta$-CyD > $\gamma$-CyD > $\beta$-CyD > $\alpha$-CyD for FBZ at pH 1.2. On the other hand, solid dispersion systems of ABZ and FBZ with $\beta$- and DM-$\beta$-CyDs were prepared by solvent evaporation method and evaluated by dissolution, differential thermal analysis and powder x-ray diffractometry. The dissolution rates of ABZ- and FBZ-DM-$\beta$-CyD solid dispersions were much faster than those of drugs alone, corresponding physical mixtures and tablets on market both at pH 1.2 and 6.8. Although dissolution rates of all samples at pH 6.8 were by far lower than those obtained at pH 1.2, as explained by pH-solubility profiles for ABZ and FBZ, the dissolution rates at pH 6.8 of ABZ from $\beta$- and DM-$\beta$-CyD solid dispersions exceeded the respective equilibrium solubility (23.9 $\mu\textrm{g}$/ml). Fast dissolution of ABZ from solid dispersions with CyDs was attributed to the reduction of drug crystallinity and particle size which was supported by DTA and powder x-ray diffractometry. Consequently these results suggest that solid dispersion systems with CyDs may provide useful means to markedly enhance the solubility and dissolution of benzimidazole antelmintic drugs.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.584-589
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• 2005

This study was carried out to investigate the effects of different types of $\beta$-cyclodextrin ($\beta$-CD) treatments on chemical and sensory characteristics of cholesterol-reduced cream cheese. The cholesterol removal rates were 92.0% in cream cheese treated by powder $\beta$-CD, and 82.6% in cream cheese treated by crosslinked $\beta$-CD. Amounts of short-chain fatty acid and free amino acids were significantly lower in cream cheese made by crosslinked $\beta$-CD-treated milk, especially after 2 weeks storage, compared with those of no $\beta$-CD-treated control and cream cheese made by powder $\beta$-CD treated milk. Among rheological properties, cohesiveness was significantly higher, and gumminess in cream cheese made by crosslinked $\beta$-CD-treated milk was slightly lower than others. In sensory analysis, no difference was found in texture among treatments, while bitterness was lower in the early stage of storage, and overall quality was higher score, in cream cheese made by crosslinked $\beta$-CD-treated cream at 3 and 4 week storage, compared with those in control and powder $\beta$-CD-treated group. The present study indicated that crosslinked $\beta$-CD treatment resulted in an efficient cholesterol removal rate over 80% and a deceleration of ripening, which may provide a longer shelf life without significant adverse effects in chemical and sensory properties.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.3
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• pp.174-180
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• 2000

Cyclodextrin glucanotransferase (CGTasa) from Thermoanaerobacter sp. was adsorbed on the ion exchange resin Amberlite IRA-900. The optimum conditions for the immobilization of the CGTase were pH6.0 and 600 U CGTase/g resin, and the maximum yield of immobilization was around 63% on the basis of amount ratio of the adsorbed enzyme to intial amount in the solution. Immobilixation of CGTase shifted the optimum temperature for the enzyme to peoduce transglycosylated xylitol from 7$0^{\circ}C$ to 9$0^{\circ}C$ and improved the thermal stability of immobilized CGTase, especially after the addition of soluble starch and calcium ions. Transglycosylated xylitol was continuoncly produced using immobilized CGTase in the column type packed bed reactor, and the operating conditions for maximum yield were 10%(w/v) dextrin (13 of the dextrose equivalent) as the glycosyl donor, 10%(w/v) dextrin (13 of the dextrose equivalent) as the glycosyl donor, 10%(w/v) xylitor as the glycosyl acceptor, 20mL/h of medium fiow rate, and 6$0^{\circ}C$. The maximum yield of transglycosylated xylitol and productivity were 25% and 7.82 g.L-1.h-1, respectively. The half-life of the immobilized CGTase in a column type packed bed reactor was longer than 30 days.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.205-211
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• 1995

To increase the solubility of iodine and iodine releasing agents, which are used widely as a topical broad spectrum antiseptics and disinfectant sanitizers, its inclusion complexes were prepared and studied. Inclusion complexes of iodine with ${\beta}-cyclodextrin$ were prepared by coprecipitation method and complex formation was acertained by differential scanning calorimetry and microscopic observation. Iodine content of inclusion complex was determined by means of iodometry. Tablets containing inclusion complex were manufactured with sugar, citric acid, magnesium stearate, dextrose. Stability of inclusion complexes and tablets was evaluated by accelerated stability test, and comparing with PVP-iodine. During preparation, use of 50% ethanol solution is preferable to water as the medium because the former resulted in more stable complex for a month under accelerated storage conditions. Solubility of iodine in KI aqueous solution was 0.048 g/ml and lower than in 50% ethanol solution. Inclusion complex and its tablets were very stable at severe condition for one month, and comparable to PVP-iodine in the aspect of stability. Inclusion complex tabletswere not affected with citric acid, sugar, dextrose, and direct tableting method was recommendable because wet granulation using ethanol gave some release of included iodine during process.

• Food Science and Preservation
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• v.9 no.2
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• pp.189-193
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• 2002

This study was conducted to evaluate the quality and the quantity for manufacturing vinegar powder using spray drying. The $\beta$-cyclodextrin(CD) and gum arabic(GA) were used as well materials and the mixing ratio of CD and GA was ranged from 10:0 to 0:10. The moisture content of the vinegar powder of 2.5 of CD and 7.5 of GA was lowest among the other mixing ratios. At this proportion, the titratable acidity was highest as it had much included vinegar. The heat stability was not varied much with mixing ratio. However the stability of heat was maintained. Further the water absorption of powder was comparatively low. The manufactured powder vinegar shape was smooth round particles and stable structure by SEM and the particle size was small enough to form capsulation. In sensory evaluation, under these conditions the sourness was highest at 3.5. Therefore, the optimal mixing ratio at 2.5 of CD and 7.5 of GA in wall material was selected.