• Applied Biological Chemistry
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• v.37 no.6
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• pp.463-471
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• 1994

Physicochemical properties, gelatinization and retrogradation characteristics of surfactant added sweet potato starches were investigated. Three different surfactants, SSL (sodium stearoyl-2-lactylate), Dimodan (mono/diglyceride) and SE1670 (sucrose fatty acid ester 1670) were used. Shapes and crystallinities of starch granules were not changed by the addition of surfactants. Total lipid contents increased and the amylose content decreased by the addition of surfactants and the order was as follows: SE1670>SSL>Dimodan. The swelling power and solubility at $80^{\circ}C$ decreased in the surfactant added starches. By amylograph, initial gelatinization temperature of untreated sweet potato starch was $72.5^{\circ}C$, and did not change by the addition of surfactants, but SE1670 or Dimodan added starch showed the peak viscosity. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C$ and 1.3cal/g, respectively. The peak temperature increased by the addition of surfactants, while the enthalpy decreased. In gelatinization by alkali, the viscosity was lower in surfactant added starches than in untreated starch at concentration. The degree of retrogradation by ${\alpha}-amylase-iodine$ method was a lower in SSL and SE1670 added starches than untreated starch and the enthalpy by DSC also decreased in surfactant added and retrograded starches.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.582-592
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• 1995

To measure rheological properties of the starch dough, an Extrusion Capillary Viscometer(ECV) cell was self-made and attached to Instron machine(Model 1140). Apparent viscosities of corn and waxy corn starch doughs were measured and their gelatinization degrees were determined by enzymatic analysis. When corn and waxy corn starch doughs with $36{\sim}52%$ moisture content were heated at $60{\sim}100^{\circ}C$, come-up time of the cold point of doughs decreased from 220 sec to 140 sec with increased in the moisture content. In the measurement range of $36{\sim}52%$ moisture content and $60{\sim}100^{\circ}C$ heating temperature, both corn and waxy corn starch doughs showed pseudoplastic flow behaviors. At the same shear rate, both shear stress and viscosity of starch dough decreased as the moisture content increased. At the moisture content above 44%, the shear stress and viscosity of starch dough decreased as the heating temperature increased from $60^{\circ}C\;to\;70^{\circ}C$, but increased as the heating temperature increased from $80^{\circ}C\;to\;100^{\circ}C$. When the moisture content increased and heating temperature, 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 effects of moisture content on the viscosity of starch dough were examined by Arrhenius equation. As the moisture content increased, viscosity of starch dough decreased. But the effect of moisture content was greater in the range of $80{\sim}100^{\circ}C$ than in the range of $60{\sim}70^{\circ}C$ heating temperature.

• Korean journal of food and cookery science
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• v.3 no.1
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• pp.20-30
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• 1987

Kyongdan is a kind of Korean rice cake made from glutinous rice powder. This study attempted to clarify the factors which affect the textural characteristics, and to examine the effects on sensory characteristics and texture of Kyongdan in various soaking time, temperature and volume of adding water in the preparation of Kyongdan. Evaluation was conducted through sensory evaluation and objective evaluation. The degree of gelatinization in various storage time and temperature were evaluated by $\beta$-amylase digestibility. The results were summarized as follows. 1. In preparation, the significant factors were the temperature and volume of water, number of kneading, condition of powder, and the relationships between soaking time and temperature of water and between volume and temperature of water and between volume of water and number of kneading and between volume of water and salt. 2. In sensory evaluation on the various soaking time and temperature and volume of water, the most favorite tendency on the overall quality was at the addition level of hot water of 25% with glutinous rice powder made by soaking for 12 hours. This condition corresponded to the low level of hardness, gumminess, chewiness and the high level of springiness and cohesiveness in comparision with Instron measurement. 3. The degree of gelatinization were decreased rapidly during two days of storage. In storage temperature, Kyongdan which was stored at $0^{\circ}C$, showed the most low level of the degree of gelatinization at the same storage time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.421-428
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• 2007

Eight varieties of milled rice showing different palatabilities were studied in order to identify the relationship between physicochemical properties of carbohydrate components and their fine structure. Gopumbyeo showed the highest palatability value among the eight varieties tested. Both peak viscosity and breakdown were hightest in Hitomebore, and lowest in Mihyangbyeo. No relationship was indicated between the palatability and gelatinization properties. The amylose content of starch showed a significant difference among the varieties tested. However, no relationship was found between the structure of amylose and the palatability of milled rice. The degree of branching(B/A value) was highest in Saechucheongbyeo, and lowest in Palgongbyeo in fine structure of amylopectin. But no relationship was indicated between the B/A values and the palatability of milled rice. Difference was indicated in properties of gelatinization of starch by differential scanning calorimetry. The enthalphy for gelatinization showed a significant difference among the varieties. However, no relationship was found between the enthalphy for gelatinization and the palatability of milled rice. Monosaccharide in endosperm was composed of rice were compound of rhamnose, fucose, ribose, arabinose, and xylose. The total content of monosaccharides was highest in Saechucheongbyeo, and lowest in Palgongbyeo. However, 7 varieties of milled rice, expect Palgongbyeo, showed no relationship between the palatability and monosaccharides contents.

• The Korean Journal of Food And Nutrition
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• v.7 no.2
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• pp.137-143
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• 1994

To optimize extrusion cooking condition of single screw extuder for production of puffed rice extrudate using response surface methodology (RSM), moisture content, barrel temperature and screw speed were determined from contour maps, showing relationship between dependent (hardness, expansion ratio, water absorption index, water solubility Index, degree of gelatinization) and independent variables. Optimum operational conditions for production of puffed rice extrudate with suitable quality properties were moisture content 17%, barrel temperature 1$25^{\circ}C$ and screw speed 210 rpm, respectively.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.15-22
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• 2005

Extrusion with enzyme treatment improved processing characteristics and physiological activity of whole grains, strongly suggesting industrial potential of whole grains for production of cereal-based functional foods containing activated nutraceuticals. Physicochemical properties of whole grains prepared by extrusion were characterized in terms of vitamin, mineral, and resistant starch contents, gelatinization, and digestibility in comparison with those of raw and roasted grains. Extrusion increased grain gelatinization, with degree of gelatinization in extruded barley being seven times higher than that of raw barley. Extrusion improved digestibility of whole grains in comparison with those of raw and roasted grains. Dispersibility of starch was improved through extrusion, while content of resistant starch decreased. Release of ${\beta}-sitosterol$ present in whole grains increased 13-fold when both extrusion and enzyme treatment were used.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.317-324
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• 1991

Gelatinization behaviours and gel properties of hydroxypropylated corn starches (HPCS) were investigated with differential scanning calorimeter, amylograph and rheometer. Gelatinization temperature of HPCS decreased as degree of substitution increased. The retrogradation of corn starch was greatly reduced by hydroxypropylation, indicating that the association of starch molecules was sterically hindered by hydroxypropyl groups. In HPCS, gel was formed slowly and gel strength decreased resulting in soft and sticky texture. Texture profiles of HPCS gels were similar to those of tapioca and waxy corn starch. HPCS has shown a remarkable increase of paste transparency compared to native corn starch.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.3
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• pp.370-375
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• 1999

This study was attempted to examine the sensory quality, the degree of gelatinization, color, texture and moisture content of Paeksulgies made with black color rice. The results were as follows: The moisture contents was about 32-36%. L-value on the control group was high, 94.74 and $A_1$, $A_2$, and $C_1$ group were 78.72, 78.58, and 78.43 respectively. As the amount of color rice was increased, L-value on the Paeksulgis was decreased. The gelatinization of Paeksulgis added with color block rice was most increased at C group and D group. In sensory quality. Paeksulgis added with 4-10% block color rice showed the most favorable sensory evaluation.

• Korean journal of food and cookery science
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• v.8 no.3
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• pp.333-341
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• 1992

The physicochemical, rheological and sensory characteristics of 'BACKSULGIES', which was added with potato peel, guar gum or polydextrose, were investigated. The maximum acceptable addition ratio of dietary fiber to 'BACKSULGI' was 10%. And optimal addition ratio was 3% for all samples. The water binding capacity was affected by dietary fiber sources and incubation conditions (temperature and time). The Guar gum had me highest value of water binding capacity. The solubility was highly related with water binding capacity and me swelling power was increased with temperature increment. The degree of gelatinization was not significantly different with dietary fiber sources. But me values of gelatinization of 'BACKSULGIES' added with dietary fibers were significantly higher than mose of 'BACKSULGI' with no dietary fiber. Generally hardness and brittleness incresed along with storage time. But me hardness of 'BACKSULGIES' added with dietary fibers was significantly lower man those of 'BACKSULGI' with no dietary fiber. The retardation effect of dietary fibers for retrogradation of 'BACKSULGIES' was also proved by time constant determination of Avrami equation. Sernsory evaluation revealed that me addition of dietary fibers did not reduce the organoreptic quality. Therefore potato peel 3%, guar gum 3%, polydextrose 3% were optimum addition ratio which could be accepted as conventional 'BACKSULGI'. As me results of this study, it was proved mat the additions of dietary fibers to 'BACKSULGI' had the retardation effect of retrogradation.

• Journal of the Korean Society of Food Culture
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• v.25 no.1
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• pp.82-90
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• 2010

In this study, the rheological properties of doughs blended with 5% to 20% fermented rice bran (FRB) were investigated using farinographs, amylographs, extensographs, and SEM. In the farinograph analysis, the water absorption decreased and the replacement ratio of FRB increased over the time of development of the dough. The stability time of the dough was shortened, and the degree of softening decreased with added volume of FRB. The amylograph analysis showed that the temperature at the beginning of gelatinization showed a tendency to increase with increasing replacement ratio of FRB, but the gelatinization temperature showed no significant difference between the FRB-added groups and control group. The extensograph analysis showed that when the replacement ratio of FRB was over 10%, the extension of the dough decreased while the resistance was increased. In the SEM analysis, the added dough with less than 10% FRB had similar characteristics in gluten matrix and gas bubbles to those of the control of wheat flour alone. It was concluded that an added FRB volume of below 10% is most suitable for bread making.