• Polymer(Korea)
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• v.30 no.4
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• pp.338-349
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• 2006

Fully or nearly fully(8-cholesteryloxycarbonyl)heptanoated polysaccharide derivatives were synthesized by reacting cellulose, amylose, chitosan, chitin, alginic acid, pullulan or amylopectin with (8-cholesteryloxycarbonyl)heptanoyl chloride (CH8C), and their thermotropic liquid crystalline behaviors were investigated. Like in the case of CH8C, all the polysaccharide derivatives formed monotropic cholesteric phases with left-handed helicoidal structures whose optical pitches $({\lambda_m}'s)$ decrease with increasing temperature. Amylopectin derivative also formed a monotropic cholesteric phase with lefthanded helicoidal structures but, in contrast with the other derivatives, did not display reflection colors over the full cholesteric range, suggesting that the helicoidal twisting power of the cholesteryl group highly depends on the branched structure in amylopectin. The thermal stability and degree of order in the mesophase, the magnitude of ${\lambda}_m$ at the same temperature, and the temperature dependence of the ${\lambda}_m$ observed for polysaccharide derivatives were entirely different from those reported for the polymers in which the cholesteryl groups are attached to flexible or semiflexible backbones through flexible spacers. The results were discussed in terms of the difference in the chemical structures of the main and side chains and flexibility of the main chain.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.117-122
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• 2003

Starches from 4 rice cultivars, including Whachungchalbyeo and Whachungbyeo, together with two correspondiug conversion mutants with giant embryonic phenotype, Whachungchal-giant embryonic rice and Whachung-giant embryonic rice, were isolated to compare its physico-chemical properties. The amylose content and the length of glucose chains in the fractionated amylose was reduced in response to conversion of the rice cultivars for developing giant embryonic phenotype. For the fine structure of amylopectin, conversion to giant embyonic rice cultivars accompanied with slight increase in the length of B chain plus decrease in the amount of A chain, and also a slight increase in average glucose chains length of amylopectin fractions could be observed. X-ray diffractogram revealed 4 cultivars to be the representative A types. We could also obtain the results that the hydrolysis rate by glucoamylase in the waxy rice cultivars decreased in response to conversion to the giant embryonic rice cultivars, while the rate increased in the non-waxy rice cultivas. Termination temperature for gelatinization was observed to decrease in response to conversion into the giant embryonic rice cultivars, however, the enthalpy for gelatinization was found to increase with the same conversion process.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.1-8
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• 1988

The physicochemical properties and gel-forming properties of corn & red bean crude starches were investigated. The results were as follows: 1. The shape of corn crude starch granule was polygonal and the mean value of minor axis and major axis were $11.5\mu\textrm{m}$ and $14.9\mu\textrm{m}$, respectively. In the meantime, the shape of red bean crude starch granule was oval and the mean value of minor axis and major axis were $22.3\mu\textrm{m}$ and $31.4\mu\textrm{m}$. 2. Amylose content of corn and red bean refined starch were 16.52 and 43.61% respectively. 3. Blue value of corn and red bean crude starch were 0.099 and 0.842, respectively. 4. Amylose of corn had molecular weight of 107,000 and degree of polymerization of 660. Amylopectin had degree of branching of 6.9 per 100 glucose units and glucose units of 14.6 persegment of amylopectin. Amylose of red bean had molecular weight of 118,000 and amylopectin had degree of branching of 5.2. 5. Water binding capacities of corn and red bean starch were 238.5 and 284.8. 6. Both swelling powers of corn and red bean starch were increased rapidly from $70^{\circ}C$ to $90^{\circ}C$. 7, Gelatinization of corn and red bean were 75.6 and $61.8^{\circ}C$. 8. Brabender hot-paste viscosities of corn at 6% and 8% showed the similar amylogrm patterns with peak viscosity. And red bean had no peak viscosity. 9. The difference of sensory characteristics for ‘Mook’ and kidney bean & red bean starch gels was significant.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.521-527
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• 1996

Some structural characteristics of kidney bean starches (3 varieties : Pink kidney bean, Red kidney bean and White kidney bean) were investigated. The amylose content and the ${\beta}$-amylolysis limit of kidney bean starches were $32.6{\sim}34.5%$ and $69.9{\sim}71.0%$, respectively. The kidney bean amylopectin was composed of super long chain of ${\overline{DP}}$ above 60 ($5.28{\sim}12.62%$), B chain of ${\overline{DP}}$ $45{\sim}60\;(29.85{\sim}33.65%)$ and A chain of ${\overline{DP}}\;10{\sim}20(22.94{\sim}29.85%).$ The chain distribution of kidney bean starches were different from variety to variety. The acid (2.2 NHCI) hydrolysis of kidney bean starches showed, as hydrolysis time increased, the patterns of three stages. The acid hydrolysis rate and iodine reaction of acid treated starches were different from variety to variety As acid hydrolysis time increased, the amylose and the ${\alpha}$-1.6-glucosidic linkage of amylopectin of amorphous state were gradually hydrolyzed. Finally, the chain of ${\overline{DP}}$ 20 of crystalline state was left in the acid treated starches.

• Food Science and Preservation
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• v.21 no.2
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• pp.286-293
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• 2014

In this study, one GRAS strain was screened from doenjang, a traditional Korean fermented food, as a microorganism producing amylase due to the formation of a clear zone on the medium including soluble starch. From the analysis of the gene sequence of 16S ribosomal RNA, the strain was identified as Bacillus subtilis and was therefore named Bacillus subtilis CBD2. When the nutrient broth medium was prepared with 3% NaCl, 5% glucose, and the initial medium pH 7.0, the B. subtilis CBD2 showed maximum growth. Among soluble starch, corn starch, maize amylopectin, and wheat starch, soluble starch was the most effective carbon source in the production of amylase by B. subtilis CBD2. The amylase from B. subtilis CBD2 showed the highest activities at pH 8.0 and $50^{\circ}C$, and corn starch was the most proper substrate for the enzyme activity. When corn starch was used as a substrate, the production of sugars through enzyme activity increased for 24 h, and then the enzyme activity became constant.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.50-58
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• 2014

Makgeolli, known as takju, is a traditional alcoholic beverage which is native in Korea. It is made from various rice and other cereals. This study is carried out to compare the physicochemical characteristics and functional quality of makgeolli from various rice cultivars according to different amylose contents and amylopectin compositions. The 'Goami2', 'Goami3', and 'Goami4' have high amylose contents and lower proportional degrees of polymerization (DP) 6~12 and higher proportions of DP 13~24 in amylopectin of milled rice. Various variations are shown in pasting properties (viscosities) and gelatinization characteristics, and it is supposed to be related to both the amylose contents and the amylopectin compositions of raw rice. The makgeolli is being manufactured by using the 2-step-brewing method. The makgeolli is analyzed for alcohol contents, pH levels, total acids, Hunter color values and organic acid compositions. The makgeolli of 'Goami2', 'Goami3', and 'Goami4' have showed higher makgeolli yields, lower ethanol contents and less sweetness than other cultivars, and they also have high non-digestible carbohydrates contents which are derived from their high non-digestible carbohydrates contents in milled rice. Therefore, we are able to suggest that it is necessary to improve the makgeolli fermentation processes of 'Goami2', 'Goami3', and 'Goami4'.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.04a
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• pp.180-181
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• 2005

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.04a
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• pp.102-102
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• 2018

• Applied Biological Chemistry
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• v.27 no.4
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• pp.271-277
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• 1984

Molecular weight of Exo-maltotetraohydrolase produced by Pseudomonas stutzeri IAM 12097 was estimated to be approrimately 63,000 and 60,000 with SDS-polyacrylamide gel electrophoresis and Sephadex-G-100 gel filtration, respectively. The isoelectric point was appeared to be pH 4.8. Optimum pH, the stable pH range and optimum temperature of this enzyme were pH 6.6, $pH6.0{\sim}10.5\;and\;45{\sim}50^{\circ}C$. The enzyme was stable below $40^{\circ}C$ and was rapidly inactivated above $55^{\circ}C$. This enzyme was inactivated completely by $Ag^+,\; Hg^{++},\;I_2$ and ${\beta}-cycoldextrin$, and slightly by EDTA, ${\rho}-CMB$ and IAA. Michaelis constant(Km) of this enzyme toward soluble starch, amylose and amylopectin were 7.70mg/ml, 6.17mg/ml, 5.56mg/ml, respectively.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.79-86
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• 1990

Cyclodextrin hydrolase from Bacillus stearothermophilus KFCC 21203 was purified and the properties of the purified enzyme were investigated. The enzyme was purified 15 folds with 77 % recovery by ammonium sulfate fractionation, DEAE-cellulose chromatography, and Ultro AcA 34 gel filtration. The specific activity and the molecular weight of the enzyme were 1.30 units/mg protein and about 29,500, respectively, The maximum activity of the enzyme was shown at $55^{\circ}C$ and pH 5.5. However, stable temperature and pH were $40^{\circ}C$ and $5.0{\sim}8.0$, respectively. The Km value for ${\gamma}-cyclodextrin$ was $3.78{\times}10^{-3}$ M. The degradation activity of the enzyme was selectively high for ${\gamma}-cyclodextrin$, and very low for ${\beta}-cyclodextrin$, but not for ${\alpha}-cyclodextrin$. The decomposed products of ${\gamma}-cyclodextrin$ were mainly glucose and maltose, and a little mlatotriose. The activity of the enzyme was very high for amylose, potato starch, corn starch, amylopectin and maltooligomer, and relatively high for glycogen and dextrin. The decomposed products of them were mainly glucose and maltose.