• Applied Biological Chemistry
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• v.40 no.6
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• pp.508-513
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• 1997

Thermal characteristics and granular morphology on enzyme-resistant starches (RS) formed during heat-moisture treatment (HMT) and retrogradation were investigated in high amylose corn starches, Hylon V and Hylon VII. With each treatment, both starches showed a similar trend in the increase of RS, but RS yield of Hylon VII is higher than that of Hylon V. Specially, RS was increased remarkably by HMT. It was more than doubled from 11.4% to 26.6% for Hylon V and from 15.9% to 32.8% for Hylon VII. A small increase of RS resulted from retrogradation. HMT on starch increased gelatinization temperature, decreased enthalpy. Retrograded starch exhibited small three endothermic transitions at $94^{\circ}C$, $110^{\circ}C$ and $140^{\circ}C$ in differential scanning calorimetry (DSC) thermogram due to the remained ungelatinized starch granules, dissociation of amylose-lipid complex and melting of recrystallized amylose, respectively. Enzyme-resistant starches isolated from native and heat-moisture treated starches showed a broad endothermic transition at higher temperature than native starch, while retrograded starch exhibited a very sharp peak at ${\sim}150^{\circ}C$ due to the melting of amylose crystallites. Under microscopy, starch granules with HMT was not changed, but retrograded starches showed the aggregates of starch granules because amylose leached out during gelatinization. Iodine stained RS clearly showed the differences in enzyme hydrolysis on the native, heat-moisture treated and retrograded starches.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.117-122
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• 1994

The characteristics of amylose-lipid complex(AL-complex) and cyclodextirn-lipid complex(CL-complex) were investigated by using Differential Scanning Calorimetry(DSC). The enzymatic hydrolysis of amylose which was liberated from AL-complex by the addtion of ${\beta}-cyclodextrin({\beta}-CD)$was also studied. The melting temperatures of AL-complex in corn, wheat, and rice starch were above $100^{\circ}C$ and there were no differences among them. In the presence of lysolecithin, the melting enthalpy and temperature of AL-complex were increased and lysolecithin was very effective in the formation of AL-complex. When ${\beta}-CD$ was added to AL-complex, the endothermic peak of AL-complex at $100^{\circ}C$ decreased and that of CL-complex at $70^{\circ}C$ appeared. These results indicated that the amylose was released from AL-complex by substituting ${\beta}-CD$ for amylose, then by forming CL-complex. As the added amount of ${\beta}-CD$ increased, the peak of AL-complex decreased whereas that of CL-complex increased. Enzymatic hydrolysis rate of AL-complex increased in the presence of ${\beta}-CD$, suggesting that amylose was dissociated from AL-complex and hydrolyzed by amylase.

• Food Science and Preservation
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• v.12 no.2
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• pp.101-106
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• 2005

This study was carried rut to investigate the quality properties of two cocked germinated-brown rices(A- and B-product). Color value of A- and B-product were L=68.46, a=0.92, b=9.49 and L=69.32, a=-1.10, b=9.77, respectively. Moisture content of those was $64.5\%$. The free sugar contents of A-product were $0.2\%$ glucose, $0.15\%$ sucrose, $0.18\%$ maltose, and those of B-product were $0.14\%$ glurose, $0.50\%$ sucrose, $0.17\%$ maltose, respectively. Vitamin E content in A-product was $30.7\;{\mu}g\;100\;g$ and $46.9\;{\mu}g\;100\;g$ in B-product. Total dietary fiber contents were $2.8\%$, and $2.2\%$, respectively. The DSC(differential scanning calorimetry) characteristics of two cooked germinated-brown rices showed similar pattern. Onset temperature and gelatinization enthalpy of peak 1 were $56.5^{\circ}C$, 5.46 J/g in A-product and $56.2^{\circ}C$, 5.56 J/g in B-product, respectively. Onset temperature and melting enthalpy of peak 2 were $109.5^{\circ}C$, 0.33 J/g in A-product and $108.9^{\circ}C$, 0.37 J/g in B-product, respective1y. Sensory properties of cocked germinated-brown rices were affected by appearance, taste and texture. Palatability score of B-product was higher than that of A-product.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.288-293
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• 2004

Differential scanning calorimetry (DSC) was used to study effects of sucrose and gluten on wheat starch glass transition, gelatinization, and retrogradation. Glass transition temperature ($T_{g}$) of wheat starch decreased as the ratio of sucrose or gluten to starch increased. Both peak temperature ($T_{G}$) and enthalpy values of gelatinization endotherm increased or decreased with increasing ratio of sucrose or gluten, respectively. Wheat starch gel with no sucrose and gluten recrystallized up to 4 weeks of storage at $4^{\circ}C$, whereas those with sucrose and gluten completed recrystallization within 1 week. Both wheat starch gels with no sucrose and gluten, and those with sucrose and gluten at storage temperature of $32^{\circ}C$ recrystallized up to 4 weeks, with wheat starch-sucrose-gluten (1 : 0.5 : 0.12) system, which had highest ratios of gluten and sucrose to starch, showing lowest recrystallization. Nucleation and propagation rates of starch gel recrystallization based on polymer crystallization principles can be converted into peak width (${\delta}T$) and peak temperature ($T_{R}$) of retrogradative endotherm by DSC, because higher nucleation rate at storage temperature of $4^{\circ}C$ close to $T_{g}$ showed higher ${\delta}T$, whereas higher propagation rate at $32^{\circ}C$ (close to $T_{G}$) had higher $T_{R}$.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1285-1290
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• 2000

The objective of this study was to evaluate the characteristics on the thermal denaturation of free drip released from pork loin during chilled storage using DSC (differential scanning calorimetry) with pH, concentration of NaCl and phosphate. The increasing of pH stabilized the heat resistance of the proteins in drip. A $T_1$ greatly increased of $T_{max}$ by $6.33^{\circ}C$ incline from pH 5.5 to 6.5. And increasing the concentration of NaCl destabilized the heat resistance of drip. $T_1$ showed the greatest reduction of $T_{max}\;(9.41^{\circ}C)$ in the presence of 5% NaCl. The presence of STPP (Sodium Tripolyphosphate) enchanced the thermal stability of pork drip by $5.84^{\circ}C$ in the presence of 0.5% STPP. As temperature increased from 40 to $100^{\circ}C$, lightness $(L^*)$ increased from 41.1 to 69.5, while redness $(a^*)$ decreased from 26.70 to 5.40. Particularly, both values of $L^*-$ and $a^*-$ greatly changed by 78% from 40 to $60^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.123-128
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• 1993

The polyesters (polyhydroxyalkanoates; PHAs) production capability in a two-step cultivation of Alcaligenes eutrophus H16(ATCC 17699) was investigated by using various organic carbon sources. The carbon sources used included linear $C_2~C_10$ monocarboxylic acids, $C_3~C_10$ dicarboxylic acids, crotonic acid, and several linear vicinal and $\omega$-diols. The polyesters synthesized were characterized by 500 MHz $^1 H-NMR$ spectroscopy, intrinsic viscosity$[\eta]$ measurement in chloroform and differential scanning calorimetry (DSC). The PHAs synthesis data showed that the use of C-odd ($C_3, C_5, and C_7$) monocarboxylic acids resulted in poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(3HB-co-3HV) (3HV content ranging 40 to 70 mol%) while the use of $C_9$ substrate gave the copolyester containing only 4 mol% of 3HV. All culture products obtained on $C_3$~C$_{10}$ dicarboxylic acids gave exclusively P(3HB). 500 MHz $^1 H-NMR$ analysis showed that all polyesters synthesized generally contained 1~2 mol% 3HV even for the unrelated substrates such as the carboxylic acids with even number of carbon. When $\alpha, \omega$-diols with even number of carbon were used as substrates, 4-hydroxybutyrate(4HB) was inserted into the polyester chain composed of P(3HB-co-4HB). Vicinal diols were generally not utilized by the bacterium for polyester production.n.

• Polymer(Korea)
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• v.32 no.4
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• pp.366-371
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• 2008

The controlled/living cationic polymerization of $\alpha$-methylstyrene (${\alpha}MeSt$) and sequential block copolymerization of isobutylene (IB) with ${\alpha}MeSt$ were achieved using 2-chloro-2,4,4-trimethylpentane (TMPCl)/titanium tetrachloride ($TiCl_4$)/titanium isopropoxide ($Ti(OiPr)_4$)/2,6-ditert-butylpyridine (DtBP) initiating system in $CH_3Cl$/hexane(50/50 v/v) solvent mixture at $-80^{\circ}C$. The polymerization rate decreased with increasing $[Ti(OiPr)_4]/[TiCl_4]$ ratio in the homopolymerization of ${\alpha}MeSt$. The effects of $[Ti(OiPr)_4]/[TiCl_4]$ ratios and $PIB^+$ molecular weight on the polymerization rate and blocking efficiency were also investigated. Well-defined poly(isobutylene-b-$\alpha$-methylstyrene)s were demonstrated by $^1H$-NMR and triple detection SEC; refractive index (RI), multiangle laser light scattering (MALLS) and ultraviolet (UV) detectors. Blocking efficiencies for the poly(isobutylene-b-$\alpha$-methylstyrene)s of almost 100% were obtained when ${\alpha}MeSt$ was induced by PIB's of $M_n\;{\geq}\;41000$ at $[Ti(OiPr)_4]/[TiCl_4]=1$. Differential scanning calorimetry (DSC) of the block copolymers showed two glass transition temperatures, thereby demonstrating microphase separation.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.541-548
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• 2012

New candidates composed of anthracene and 4-alkylethynylbenzene end-capped oligomers for OTFTs were synthesized under Sonogashira coupling reaction conditions. All oligomers were characterized by FT-IR, mass, UV-visible, and PL emission spectrum analyses, cyclic voltammetry (CV), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), $^1H$-NMR, and $^{13}C$-NMR. Investigation of their physical properties showed that the oligomers had high oxidation potential and thermal stability. Thin films of DHPEAnt and DDPEAnt were characterized by spin coating them onto Si/$SiO_2$ to fabricate top-contact OTFTs. The devices prepared using DHPEAnt and DDPEAnt showed hole field-effect mobilities of $4.0{\times}10^{-3}cm^2$/Vs and $2.0{\times}10^{-3}cm^2$/Vs, respectively, for solution-processed OTFTs.

• Journal of the Korean Chemical Society
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• v.42 no.3
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• pp.315-322
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• 1998

A series of new dimesogenic compounds were prepared and their thermotropic and liquid crystalline properties were studied by differential scanning calorimetry and on a hot-stage of a polarizing microscope. These compounds, 1,10-bis[2,5-bis(4-substitutedphenoxycarbonyl)phenoxy]decanes, consist of two bis(ρ-substitutedphenoxy)terephthalate units interconnected through a oxydecamethyleneoxy spacer on the central terephthaloyl units resulting in the structure of "H-shaped" dimeric twin compounds. The terminal substitutent groups were changed; X=-F, -H, -I, -Cl, -Br, $-NO_2,\;-CF_3,\;-OC_4H_9,\;-CN\;and\;-C_6H_5.$ The compounds with X=$-OC_4H_9,\;-CN\;and\;-C_6H_5$ were monotropically nematic. In contrast, the compounds with $X=-F, -H, -I, -Cl, -Br, $-NO_2\;and\;-CF_3$ were non-liquid crystals. The nematic group efficiency of these compounds was in the order of -C_6H_5>-CN>-OC_4H_9.$

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1763-1770
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• 2013

A series of the block copolymers were successfully synthesized from post-sulfonated hydrophilic and hydrophobic macromers via three-step copolymerization. The degrees of sulfonation (DS) of the copolymers (10%, 30%, or 50%) were controlled by changing the molar ratio of the hydrophilic and hydrophobic parts. The resulting block copolymers were characterized by $^1H$ NMR and other technologies. The membranes were successfully cast using dimethyl sulfoxide (DMSO) solution at $100^{\circ}C$. The copolymers were characterized to confirm chemical structure by $^1H$ NMR and FT-IR. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated that all sulfonated block copolymers exhibited good thermal stability with an initial weight loss at temperatures above $240^{\circ}C$. The membranes showed acceptable ion exchange capacity (IEC) and water uptake values in accordance with DS. The maximum proton conductivity was 184 mS $cm^{-1}$ in block copolymer-50 at $60^{\circ}C$ and 100% relative humidity, while the conductivity of Nifion-115 was 160 mS $cm^{-1}$ under the same measurement conditions. AFM images of the block copolymer membranes showed well separated the hydrophilic and hydrophobic domains. From the observed results it is that the prepared block membranes can be considered as suitable polymer electrolyte membranes for the application of polymer electrolyte membrane fuel cells (PEMFC).