• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.428-438
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• 1995

The gelatinization properties of corn and waxy corn starch doughs were examined at various moisture contents, heating temperatures and heating times. The onset temperatures of gelatinization with 1% CMC using Brabender Amylograph were $64^{\circ}C$ for both corn and waxy corn starch. In the gelatinization properties using DSC, onset temperature$(T_o)$, maximum peak temperature$(T_p)$, completion temperature$(T_c)$ and enthalpy of the corn starch were $68.15^{\circ}C,\;74.01^{\circ}C,\;85.65^{\circ}C$ and $3.2\;cal/gram$ respectively. While those of the waxy corn starch were $68.24^{\circ}C,\;75.43^{\circ}C,\;93^{\circ}C$ and $4.2\;cal/gram$ respectively. In enzymatic analysis, when the moisture content increased from 36% to 52% and heating temperature from $60^{\circ}C$ to $100^{\circ}C$, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The regression equations of gelatinization degree (Y) of starch dough in the range of $36{\sim}52%$ moisture content $(X_1)\;60{\sim}100^{\circ}C$ heating temperature $(X_2)\;and\;0{\sim}2.0$ min heating time $(X_3)$ were examined using response surface analysis. The regression equation of corn starch dough was: $Y=28.659+8.638\;X_}+15.675\;X_2+7.770\;X_3-1.620\;{X_1}^2+10.790\;X_1X_2-4.220\;{X_2}^2+0.510\;X_1X_3+1.980\;X_2X_3-6.850\;{X_3}^2\;(R^2=0.9714)$ and that of waxy corn starch dough was: $Y=32.617+12.535\;X_1+20.470\;X_2+8.608\;X_3+4.093\;{X_1}^2+13.550\;X_1X_2-4.467\;{X_2}^2+1.560\;X_1X_3+2.160\;X_2X_3-9.527\;{X_3}^2$\;(R^2=0.9621)$. As the moisture content, heating temperature and heating time increased, the reaction rate constant(k) of gelatinization increased. The greatest reaction rate constant was observed at initial 0.5 min heating time of 1st gelatinization stage. At the heating temperature of $90^{\circ}C$, gelatinization of starch dough was completed almost in the initial 0.5 min heating time. The reaction rate constant of waxy corn starch dough was higher than that of corn starch dough under the same gelatinization conditions. At the 52% moisture content, the regression equation between reaction rate constant(k) and heating temperature(T) for corn starch dough was $log\;k=11.1140-4.1226{\times}10^3(1/T)$ (r=-0.9520) and that of waxy corn starch dough was $log\;k=10.1195-3.7090{\times}10^3(1/T)$ (r=-0.9064).

• Food Science and Preservation
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• v.17 no.5
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• pp.667-673
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• 2010

Effects of substituting wheat flour with rice flour on bread-making properties were investigated. Rice(Oryza sativa L.) cultivars were 'Goami2(G2)', a functional rice containing higher non-digestible carbohydrates, and 'Chucheongbyeo (CC)', an ordinary Japonica rice. Rice flour was substituted at 10, 20 and 30% in wheat bread formulation, and the composite flour was used for yeast-leavened bread making. Peak and final viscosity of G2 rice flour was significantly lower than that of CC rice flour. Mixograph analysis indicated that replacement of G2 rice flour increased dough water absorption and mixing time compared to wheat flour. But, typical mixograph pattern was not found in the dough from composite flour with CC rice flour. As increasing the amount of rice flour, the G2 rice breads showed a significant decrease in loaf volume, but an increase in bread crumb firmness(g). For the CC rice breads, no significant difference(p<0.05) was observed in loaf volume and crumb firmness, ranging 1012~1050 cc and 433~482g, respectively. The results revealed that Chucheongbyeo is more suitable for bread-making with the composite flour of rice(10~30%) and wheat flour.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.24-33
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• 1990

The changes in water uptake rate, cooking properties, color of rice grains and gelatinization properties of brown and milled rices during storage were studied. The brown and milled rices were stored at $4^{\circ}$ and $25^{\circ}C$ for 5 and 3 months, respectively. The water uptake rate constants of rices during hydration at $30^{\circ}$ were linearly decreased during storage. The volume increase rate also showed similar trend to the water uptake rate. The terminal point of cooking of milled rice at $100^{\circ}$ in a sealed brass vessel was about a half of that of brown rice. The cooking rate of milled rice was 1.8 times faster than that of brown rice. The cooking rate constant of both brown and milled rices linearly decreased with the increase of storage time. The L(lightness) value increased for brown rice grain and remained unchanged for milled rice grain during storage. The peak viscosity of rice flours by amylograph increased during storage, but enthalpy for gelatinization decreased, as measured by differential scanning calorimetry.

• 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.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.04a
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• pp.57-60
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• 1998

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.172-173
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• 2004

• Korean journal of food and cookery science
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• v.17 no.2
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• pp.156-164
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• 2001

Four different oligosaccharides used to determine their effects on gelatinization and retrogradation of Backsulgies(BSG), Korean traditional rice cake, were cyclodextrin, isomaltooligosaccharide, fructooligosaccharide and maltotetrose, with 3 or 6%(w/w), based on the rice flour. From the Amylograph and blue value data, adding 6% cyclodextrin into the rice flour fastened the gelatinzation process, and delayed the retrogradation in stored BSG at 4$\^{C}$ for up to 3 days, probably due to its cyclic structure. Using rheometer, the hardness of freshly made BSG added with cyclodextrin was significantly lower than that of control BSG, and increased with storage time in all BSGs at refrigerated temperature. When using maltotetrose in rice flour, the hardness of BSG was also significantly low, but slightly higher than that of cyclodextrin. Hunter “L” value in BSG decreased with the addition of oligosaccharides, but the higher the level of oligosaccharide in BSG, the insignificant the Hunter “a”,“b” values of BSG. From the X-ray diffraction studies, the rice flour showed typical A pattern, and the crystallinities of all BSG gave amorphous V type. The highest peaks of X-ray patterns in BSG added with 6% cyclodextrin or maltotetrose were, however, lower than that of the control, meaning the less crystalline, retrograded starch in the former BSGs. Based on sensory evaluation, BSG added with all oligosacchrides were not significantly different in taste, flavor, chewiness, moistness and overall preferences, with slightly darker color with longer storage time, compared to the control BSG.

• Korean journal of food and cookery science
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• v.7 no.3
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• pp.1-6
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• 1991

Potato starches are obtained from Irish Cobbler (the dry type), Shepody and superior (the intermediate type) and Dejima (the moist type). Rheological properties of heat-gelatinized potato starch paste were studied to elucidate difference of various potato starches. Heat-gelatinized 3 to 7% potato starch paste showed pseudo plasticity in yield stress. As starch paste concentration increased, the values of consistency index was increased. Relationship between logarithmic consistency index and concentration of potato starch paste was linear at 5% starch concentration. Concentration dependence of consistency index and yield stress of Shepody was highest. As measuring temperature increased, the value of consistency index was decreased. Irish Cobbler starch paste at $50^{\circ}C$, Shepody, Superior and Dejima starch paste at $60^{\circ}C$ showed linear relationships with different slopes. The activation energies of Shepody starch paste was 3.97㎉l/㏖.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.590-596
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• 2005

Effects of jujube extract on physicochemical properties of dough were evaluated. Moisture, protein, and ash contents of jujube extract were 92.5, 0.5, and 0.37%, respectively at pH 4.65. Sucrose content was the highest (4,340 mg%) among free sugars of jujube extract, followed by glucose and fructose. Absorption rate increased as observed through farinogram with increasing amount of jujube extract added. Dough development time and stability decreased, whereas degree of weakness increased. Degree of extension decreased as shown in extensograph with increasing content of jujube extract, whereas degree of resistance and resistance/extensibility increased. Amylogram showed, when amount of jujube extract increased, no difference in gelatinization temperature, whereas peak viscosity decreased.

• Proceedings of the Culinary Society of Korean Academy Conference
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• 2005.04a
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• pp.11-18
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• 2005

$\blacktriangleright$ Farinograph에서 발효물을 첨가한 반죽이 반죽발전시간은 길었으나 안정도는 짧게 나타났다. $\blacktriangleright$ Extensograph에서 발효물을 첨가한 반죽이 저항성은 높았으나 신장성은 낮았다. $\blacktriangleright$ 반죽의 발효부피는 발효물을 첨가한 반죽이 낮게 나타났다. $\blacktriangleright$ 반죽의 총산도 변화는 발효물을 첨가한 반죽에서 높게 나타났다. $\blacktriangleright$ 반죽의 pH 변화는 발효물을 첨가한 반죽에서 낮게 나타났다. $\blacktriangleright$ 발효물의 첨가는 반죽의 호화특성에 영향을 주지 않았다.