• Polymer(Korea)
• /
• v.28 no.5
• /
• pp.397-403
• /
• 2004

The sulfonated PET-g-GMA ion-exchange fine fibers were synthesized by UV radiation-induced graft copolymerization using a photoinitiator, and their chemical structure and adsorption properties were investigated. The optimum values for synthetic conditions - UV intensity, reaction time, and reaction temperature were 450 W, 60 min, and $40^{\circ}C$, respectively. Maximum values of the degree of sulfonation and ion exchange capacity were 8.12 mmol/g and 3.25 meq/g, respectively. Tensile strength of sulfonated PET-g-GMA fine ion exchange fibers was lower than that of PET trunk polymer as the grafting reaction rates increased. It was shown that as for the adsorption rate of $Ca^{2+}$ and $Mg^{2+}$ by the sulfonated PET-g-GMA fine ion exchange fibers, magnesium ion is slower than calcium ion in the solution. However, in the mixture of the calcium and magnesium ions, the adsorption rate of calcium ion was much slower than that of magnesium ion.

• Elastomers and Composites
• /
• v.49 no.2
• /
• pp.110-116
• /
• 2014

We investigated the effect of the concentration of stannous 2-ethylhexanoate catalyst on the esterification rate between adipic acid (AA) and each of two PEG oligomers, diethylene glycol (DEG) and polyethylene glycol (PEG600). The concentration of the catalyst was varied from 0.15 to 2.0 wt.%. To attach hydroxy group to each end of the poly(oxyethylene-co-adipate) synthesized from AA and the PEGs, the esterification was performed with excessive PEG oligomers ([PEG]/[AA]=2) at $170^{\circ}C$. The degree of polymerization of the poly(oxyethylene-co-adipate)diol products were three. The apparent rate constant ($k_{app}$) of the esterification between AA and DEG shows the first order dependency on the catalyst concentration ($k_{app}=0.88[C_{cat}]$), whereas the $k_{app}$ of the esterification between AA and PEG600 has a relation of $k_{app}=0.123[C_{cat}]^{0.55}$ with the catalyst concentration. It is expected that the rate of esterification between AA and DEG has a non-linear dependency on the catalyst concentration as the catalyst concentration approaches to 0.22M.

• Korean Journal of Food Science and Technology
• /
• v.29 no.2
• /
• pp.302-308
• /
• 1997

${\beta}-Cyclodextrin\;({\beta}-CD)$ polymers were prepared using epichlorohydrin as a cross linking agent. The polymers were separated into ${\beta}-CD$ soluble polymer $({\beta}-CD\;SP)$ and ${\beta}-CD$ insoluble polymer $({\beta}-CD\;ISP)$ on a 10,000 molecular weight cut-off membrane (YM 10). Optimum separation conditions in the YM 10 were: transmembrane pressure 51.7 kPa, separation temperature $35^{\circ}C$, and volume concentration ratio 10. The flux was $0.025\;mL/cm^{2}/min$ under the optimum conditions. Gel permeation chromatography indicated that ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$ had a degree of polymerization of $2{\sim}8$ and over 10, respectively. The formation of an inclusion complex with hydrophobic compounds such as 4-dimethylaminoazobenzene, methyl red, and naringin was compared among ${\beta}-CD,\;{\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. The molar absorptivity for the two chromatic compounds was increased and the absorption peak was shifted in the presence of ${\beta}-CD$ polymers. Naringin, the principal flavonoid bitter tasting component of citrus fruit, had a low water solubility. The solubility of naringin was increased through the formation of an inclusion complex with ${\beta}-CD$ polymers. There was no significant difference in the formation of an inclusion complex between ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. Reduction of the bitter components from citrus products was shown to be possible when employing ${\beta}-CD\;SP$, while the usage of ${\beta}-CD$ monomer has been limited due to the low water solubility.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.4
• /
• pp.291-300
• /
• 2005

This study was focuses on the variation of isoflavone contents during seed development and their interaction with major chemical components such as protein, amino acids, saccaharides, lipid and fatty acids. During maturing, lipid, protein, and amino acid contents in soybean seeds showed the highest values at R7 stages, but isoflavone contents were increased until R8 stage. It was noted that malonyl glucosides $(64.2\%)$ are predominant forms among conjugated isoflavones followed by glucosides $(30.7\%)$, acetyl glucosides $(4.1\%)$ and aglycones $(0.9\%)$. Sucrose and stachyose were presented as a major saccharide in soybean seeds. As maturing days progressed, they were constantly increased and the highest contents were observed at R8 stage. While small quantities of raffinose, fructose, glucose, maltose, DP3 (DP: degree of polymerization), DP6, and DP7 were detected. These results showed that saccharide composition at the beginning of seed development is primarily monosaccharides with little sucrose and oligosaccharides, but as maturing days proceeds, sucrose and starch increase with concomitant decrease in monosaccharides. Sucrose and stachyose were positively correlated with isoflavone (r=0.780, 0.764 at p<0.01, respectively), while fructose, glucose, maltose, and DP7 were negatively correlated (r=-0.651, -0.653, -0.602, and -0.586 at p<0.05, respectively). Soybeans at R8 stage were high in protein and amino acid, but low in free amino acid contents. Protein and amino acid contents showed positively significant correlations with isoflavone (r=0.571 and 0.599 at p<0.05, respectively), but free amino acid content were negatively correlation with isoflavone (r=-0.673, p<0.01). The lipid content reaches its final content relatively early stage of seed development and remains constant as compared with other chemical components. Among the fatty acids, although varietal difference was presented, stearic acid and linolenic acid were gradually decreased, while oleic and linoleic acid were increased as seed maturing progressed. Lipid was significantly correlated (r=0.754, p<0.01) with isoflavones. However, neither saturated fatty acid nor unsaturated fatty acids significantly affected the isoflavone contents of maturing soybean seeds.

• Journal of Applied Biological Chemistry
• /
• v.51 no.6
• /
• pp.272-276
• /
• 2008

Purification and some properties of Xylogone sphaerospora ${\beta}$-mannanase were reprevious previous paper. Locust bean gum galactomannan was hydrolyzed by the purified ${\beta}$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography. The main hydrolysates were composed of D.P. (Degree of Polymerization) 4 and 6 galactosyl mannooligosaccharides. For elucidate the structure of D.P 4 and 6 galactosyl mannooligosaccharides, sequential enzymatic action was performed. D.P 4 and 6 were identified as ${Gal^2}{Man_3}\;(6^2-mono-O-{\alpha}-D-galactopyranosyl-4-O-{\beta}-D-mannotriose)$ and ${Gal^2}{Man_5}\;(6^2-mono-O-{\alpha}-D-galacto- pyranosyl-4-O-{\beta}-D-mannopentaose)$. To investigate the effects of locust bean gum galactosyl mannooligosaccharides on in vitro growth of Bifidobacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, B. auglutum and B. breve. Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 4 and D.P. 6 galactosyl mannooligosaccharides, respectively. B. longum and B. bifidum grew up to-fold and 6.6-fold more effectively by the treatment of D.P. 6 galactosyl mannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 6 was more effective than D.P. 4 galactosyl mannooligosaccharide on the growth of Bifidobacterium spp.

• Polymer(Korea)
• /
• v.32 no.1
• /
• pp.70-76
• /
• 2008

The PES-g-BTCA membrane was synthesized by UV irradiation method and then used to be modified into the PES anion exchange membrane by the amination reaction. Their chemical structures and adsorption properties were investigated. The degree of grafting and amination were increased with increasing the reaction time and had the maximum values of 138% and 1.20 mmol/g at 80 min, respectively. The initial thermal degradation temperature of PES membrane was $400^{\circ}C$. Which was reduced as the surface modification reaction had proceeded. The values of contact angle for PES membrane were decreased from 68.1 to $40.2^{\circ}$ with increasing the extent of amination, the water up-take and ion exchange capacity were also increased with increasing UV irradiation time until 80 min. The average pore size and BET surface area were decreased in order of PES, PES-g-BTCA, and aminated PES ion exchange membrane. Their average pore sizes were 624.8, 359.7, and 138.5 ${\AA}$, and their surface areas were 10.1,9.7 and 1.7 $m^2/g$, respectively.

• Korean Journal of Food Science and Technology
• /
• v.28 no.1
• /
• pp.44-52
• /
• 1996

Sensory properties of cooked rice were affected by the varieties and growing environments of the rice. Moistness, cohesiveness, and adhesiveness of cooked rice were highly and positively correlated each other, whereas firmness was negatively correlated with these attributes. Sixty rice samples which differed in varieties and/or growing environments were divided into four groups based on their textural properties through principal component analysis and cluster analysis. Quality type I showed the highest values for moistness, cohesiveness, and adhesiveness, and the lowest values for firmness of cooked rice. On the other hand, quality type IV showed just the opposite values. There was no significant difference among rice starches in amylose content (P<0.05). A17 (type III) and A09 (type IV) had higher blue values for starch and amylopectin than the other samples (type I and II). On the amylogram, these samples showed lower values for breakdown and higher values for setback than the other samples. Average degree of polymerization, average chain length, and average number of chains for amylose and amylopectin were 597-878 and 2660-3140, 140-230 and 17-19, and 3.1-4.9 and 140-170, respectively.

• Journal of Adhesion and Interface
• /
• v.23 no.2
• /
• pp.44-52
• /
• 2022

Epoxy resin has the disadvantage of being easily destroyed by instantaneous impact due to its high crosslinking density despite its high glass transition temperature (T_g) and excellent properties. To compensate for this, in this study, polyol was synthesized by ring opening polymerization of propylene glycol (PPG) diamine, Jeffamine D 2000 and propylene carbonate, and urethane modified epoxy was synthesized using this. The properties of the synthesized urethane modified epoxy were confirmed by FT-IR, H-NMR. To confirm the degree of improvement in impact resistance as an adhesive, a urethane modified epoxy adhesive was prepared by mixing a digylcidyl ether bisphenol A (DGEBA) with curing agent and curing accelerator. Properties test of urethane modified epoxy were shear strength, tensile strength and impact strength. As a result, excellent results were obtained in all test when the ratio of DGEBA : urethane modified epoxy was 8:2.

• Applied Biological Chemistry
• /
• v.51 no.3
• /
• pp.159-163
• /
• 2008

Xylogone sphaerospora ${\beta}$-mannanase was purified by Sephadex G-100 column chromatography. The specific activity of the purified enzyme was 8.44 units/ml protein, representing an 56.27-folds purification of the original crude extract. The final preparation thus obtained showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight was determined to be 42kDa. Konjac glucomannan was hydrolyzed by the purified ${\beta}$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography. The main hydrolysates were composed of D.P. (Degree of Polymerization) 3 and 4 glucomannooligosaccharides. For elucidate the structure of D.P 3 and 4 glucomannooligosaccharides, sequential enzymatic action was performed. D.P 3 and 4 were identified as M-G-M and M-M-G-M (G- and M- represent glucosidic and mannosidic link-ages). To investigate the effects of konjac glucomannooligosaccharides on in vitro growth of Bifido-bacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, B. auglutum and B. breve. Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 3 and D.P. 4 glucomannooligosaccharides, respectively. B. longum and B. bifidum grew up 3.9-fold and 2.8-fold more effectively by the treatment of D.P. 4 glucomannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 4 was more effective than D.P. 3 glucomannooligosaccharide on the growth of Bifidobacterium spp.

• Journal of Food Hygiene and Safety
• /
• v.35 no.1
• /
• pp.83-92
• /
• 2020

This study investigated the optimal conditions of enzymatic reaction for production of isomaltooligosaccharides (IMO) using rice flour. To manufacture IMO, commercial enzymes (Termamyl 2X, Maltogenase L, Promozyme D2, Fungamyl 800L and Transglucosidase L) were used. The sugar composition and amount of IMO were examined by HPLC with charged aerosol detector (HPLC-CAD) in each manufacturing process. Liquefaction reaction was performed according to different Termamyl 2X concentrations (0.025%, 0.05%, 0.075%, 0.1%) and reaction times (1 h, 2 h). As a result, the reducing sugar content was the highest at 138.26 g/L when 0.075% Termamyl 2X was added for 2 hours. In order to optimize simultaneous saccharification and transglucosylation, experiments on enzyme selection, enzyme concentration and enzyme reaction time were conducted. Reaction with 0.0015% Maltogenase L, 0.05-0.1% Promozyme D2 and 0.1% Tansglucosidase L was effective in decreasing glucose content and increasing content of IMO with a high degree of polymerization. A change in sugar content was observed every 6 hours to determine the optimal reaction time, and the highest IMO was produced after 36 hours of reaction (75.36 g/L). The IMO prepared under optimal conditions showed isomaltose, 35.11 g/L; panose, 11.97 g/L; isomaltotriose, 19.95 g/L; isomaltotetraose, 7.46 g/L; isomaltopentaose, 1.05 g/L at 18 brix and the ratio of IMO in the total sugar was 56.37%.