• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1086-1090
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• 1997

Morphological properties on lintnerized maize starches with different amylose content were investigated. With increasing the lintnerization periods and decreasing the amylose content, hydrolysis rate was increased. As amylose content of starch was increased, the degree of damage with acid treatment was decreased by SEM. With increasing hydrolysis, iodine affinity, apparent amylose content and ${\lambda}_{max}$ of lintnerized starches were decreased. Water binding capacities of lintnerized starches were higher than those of native starches.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.683-688
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• 1991

Wheat flour was extruded by a single-screw extruder, and used for the ethanol production of takju. The molecular structure and enzymic susceptability of extruded starch were compared to those of steam cooked one. The gel permeation chromatographic pattern of wheat flour extrudates was not significantly different from those of raw and steam cooked starches. However, the conversion rate of extruded starch into maltose by ${\alpha}-amylase$ hydrolysis was significantly faster than those of raw ad steamed starch. The molecular weight of starch estimated from GPC pattern and the intrinsic viscosity were remarkably reduced by extrusion cooking followed by the enzymic hydrolysis for 30 min, while steam cooking and enzymic hydrolysis for 30 min did not change them significantly. Extrusion-cooked flour produced alcohol 26% higher than that of steamed flour in the laboratory takju fermentation, and 10% more alcohol in the pilot plant scale takju production.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.858-862
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• 2008

The Simultaneous Saccharification and Fermentation(SSF) of ethanol production from potato starch studied with respect to growth pH, temperature, substrate concentration. The glucoamylase and Saccharomyceses cerevisiae have a capacity to carry out a single stage SSF process for ethanol production. The characteristics, termed as starch hydrolysis, accumulation of glucose, ethanol production and biomass formation, were affected with variation in pH, temperature and starch concentration. The maximum ethanol concentration of 12.9g/l was obtained using a starch concentration 30g/l, which represent an ethanol yield of 86%. The optimum conditions for the maximum ethanol yield were found to be a temperature of 38, pH of 4.0 and fermentation time of 18hr. Thus by using the control composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.40-45
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• 2001

Raw starch-digesting amylase (BF-2A, M.W. 93, 000 Da) from Bacillus circulans F-2 was converted to two components during digestion with subtilisin. Two components were separated and designated as BF-2A' (63, 000 Da) and BF-2B (30, 000 Da), respectively. BF-2A' exhibited the same hydrolysis curve for soluble starch as the original amylase (BF-2A). Moreover, the catalytic activities of original and modified enzymes were indistinguishable in $K_{m}$, Vmax for, and in their specific activity for soluble starch hydrolysis. However, its adsorbability and digestibility on raw starch was greatly decreased. Furthermore, the enzymatic action pattern on soluble starch was greatly different from that of the BF-2A. A smaller peptide (BF-2B) showed adsorb ability onto raw starch. By these results, it is suggested that the larger peptide (BF-2A') has a region responsible for the expression of the enzyme activity to hydrolyze soluble substrate, and the smaller peptide (BF-2B) plays a role on raw starch adsorption. A similar phenomenon is observed during limited proteinase K, thermolysin, and endopeptidase Glu-C proteolysis of the enzyme. Fragments resulting from proteolysis were characterized by immunoblotting with anti-RSDA. The proteolytic patterns resulting from proteinase K and subtilisin were the same, producing 63- and 30-kDa fragments. Similar patterns were obtained with endopeptidase Glu-C or thermolysin. All proteolytic digests contained a common, major 63-kDa fragment. Inactivation of RSDA activity results from splitting off the C-terminal domain. Hence, it seems probable that the protease sensitive locus is in a hinge region susceptible to cleavage. Extracellular enzymes immunoreactive toward anti-RSDA were detected through whole bacterial cultivation. Proteins of sizes 93-, 75-, 63-, 55-, 38-, and 31-kDa were immunologically identical to RSDA. Of these, the 75-kDa and 63-kDa proteins correspond to the major products of proteolysis with Glu-C and thermolysin. These results postulated that enzyme heterogeneity of the raw starch-hydrolysis system might arise from the endogeneous proteolytic activity of the bacterium. Truncated forms of rsda, in which the gene sequence encoding the conserved domain had been deleted, directed the synthesis of a functional amylase that did not bind to raw starch. This indicates that the conserved region of RSDA constitutes a raw starch-binding domain, which is distinct from the active centre. The possible role of this substrate-binding region is discussed.d.

• Journal of Ginseng Research
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• v.24 no.1
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• pp.41-45
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• 2000

Maltooligosaccharides were produced from ginseng starch by hydrolysis of $\alpha$-amylase. And it was investigated that physicochemical properties and intestinal bacteria growing effort of maltooligosaccharides. The optimum level of the ginseng maltooligosaccharides was produced when 10% ginseng starch was hydrolyzed with 50 unit of Amano A $\alpha$-amylase per gram starch at 85。C for 24h. Viscosity and water holding capacity of the ginseng maltooligosaccharides were 37.7 cps at 20。C and 110.1% at 75% relative humidity, respectively. The ginseng maltooligosaccharides enhanced the growth of Bifidobaterium infantis.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.4
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• pp.16-26
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• 2008

It is of great importance to decrease sheet break at the size press to enhance the runnability of today's high speed paper machines. To achieve this purpose it is required to control the penetration of the starch solutions at the size press. Use of ASA sizing system provides diverse advantages in improving machine runnability since it allows us to get rapid sizing development at the size press. Domestic paper industries, however, has not enjoyed these benefits of ASA sizing system mainly because of the poor efficiency of domestic corn starches used for ASA emulsification. To improve the emulsion stability and ASA sizing efficiency, it has been pointed out that new cationic starches are needed. In this study two methods of starch modifications, i.e. esterfication of cationic corn starch with OSA (Octenyl Succinic Anhydride), and acid hydrolysis by sulfuric acid were employed as methods to improve ASA sizing efficiency. The effect of these modification was compared with conventional cationic starches.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.35-41
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• 2020

This study was conducted to develop the efficient system for starch hydrolysis suppression using rutin, quercetin and dietary fiber through the statistical mixture design. The three components were replaced with wheat flour at the level of 10% and the mixed gel with three components was characterized by in vitro starch digestion. The mixture design was applied by simplex-centroid experimental model. The quadratic model (R²=0.86) was well fitted and the obtained regression equation indicated that the significant positive effects was observed in the quercetin and fiber mixture. Based on the statistical results, the best mixing ratio of quercetin and fiber was 72: 28 that led to the lowest predicted glycemic index (pGI). Their interactions on the pGI of starch digestibility were clearly visualized in the 3D surface plot. These results suggested that the mixture of quercetin and fiber interact strongly with wheat flour, consequently retarding starch hydrolysis by 15%.

• Applied Biological Chemistry
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• v.29 no.3
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• pp.248-254
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• 1986

The product specificity of Bacillus ${\alpha}-amylase$ on raw rice starch has teen studied by using HPLC and scanning electron microscopy (SEM). Analysis of starch degradation products digested by ${\alpha}-amylase$ showed considerable differences between raw and gelatinized rice. The hydrolysis of raw rice starch resulted in formation of more glucose and maltose than those of gelatinized starch. SEM revealed characteristic enzyme degradation patterns. Hollow curvatures were observed in gelatinized starch, indicating the substrate is hydrolyzed in the interior of the starch chain by Bacillus ${\alpha}-amylase$. In contrast, raw starch were hydrolyzed from the end of the substrate, resulting in pinholes over the surface of the starch granules.

• Journal of the Korean Professional Engineers Association
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• v.17 no.1
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• pp.27-35
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• 1984

When starch is hydrolyzed either by acid or by the enzymes maltase or diastase, contained in germinating barley, a yield of 80% of maltose is obtained. Maltose is built of two molecules of ${\alpha}$-glucose, bound in the position 1:4 i.e., carbon atom 1 of one glucose molecule is bound in a glucosidic bond to carbon atom 4 of the second molecule. Until around 1960, dextrose and glucose syrups were prepared from starch exclusively by acid hydrolysis. The process was corrosive, and the dextrose yield low. It was, therefore, a great step forward when pure glucoamylase in combination with bacterial ${\alpha}$-amylase made possible a complete enzymatic hydrolysis of starch to dextrose. Today several enzymatic processes are used in the industry.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.625-630
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• 1995

In order to know the effects of hot-water extracts of starches on gel formation and gel properties, some physicochemical properties and molecular distribution of the extracts were measured. Also, after acid-hydrolysis of starch gels and extract gels, extent of hydrolysis and $\overline{D.P}._n$, and molecular distribution of hydrolysis-residue were measured. Extraction ratio of grain starches (buckwheat, corn, rice, and wheat) were $4.0{\sim}6.6%$. The ratio of acorn and mungbean starches were 11.7 and 13.5%, respectively. Iodine affinity of the extracts was $17.2{\sim}17.7%$ in starches using for Mook, SM(acorn, buckwheat, and mungbean), $13.7{\sim}14.9%$ in starches not using for Mook, SNM(corn, rice, and wheat). Blue value was also higher in SM than in SNM. $\overline{D.P}._n$. of extracts of SM were bigger than those of SNM. In molecular distribution experiment, amylopectin fraction was not found from the extracts except rice starch extract. The extent of acid hydrolysis of the starch gels were $70{\sim}84%$ after 60 days, and the extent of the extract gels were $22{\sim}35%$. The extent of hydrolysis of starch gels and extract gels made with SM were lower than those of SNM.