• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.54-58
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• 1992

The reological properties of commercial corn starch solutions at various concentrations($4{\sim}9%$) and temperatures($30{\sim}60^{\circ}C$) were investigated. The rheological behavior of corn starch solutions was illustrated by Herschel-Bulkley equation and exhibited pseudoplastic behavior with yield stress. The degree of pseudoplasticity of starch solution increased as the starch concentration increased but was independent on temperature. Apparent viscosity and yield stress of starch solutions were exponentially dependent on concentration and temperature. The critical concentrations for sol-gel transition and for the onset of close-packing of the starch granules were $6.22{\sim}6.52%\;and\;2.68{\sim}2.78%$ respectively.

• Food Engineering Progress
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• v.21 no.4
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• pp.341-350
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• 2017

The relationship of in vitro starch digestibility and gel strength was investigated at various concentrations (10-30%) of rice cultivars with different amylose contents (27.9, 17.9, and 5.2%). As the rice flour concentration increased, predicted glycemic index decreased, but gel strength increased regardless of amylose contents. Gel strength correlated strongly with amylose content, whereas in vitro starch digestibility was more highly affected by rice flour concentration than by amylose contents. Moreover, the impact of degree of gelatinization on in vitro starch digestibility of high amylose rice was also examined in terms of structural features and rheological properties. The digestion rate of fully gelatinized flour was 1.7 times higher than that of native flour, while the disrupted structure with a different gelatinization degree during starch digestion was visually demonstrated through the X-ray diffraction and molecular distribution analysis. The rice flour changed from an A-type to a V-type pattern and showed difference in crystalline melting. The low molecular weight distribution increased with increasing degree of gelatinization during starch digestion. The apparent viscosity also increased with degree of gelatinization. These results demonstrated that the starch digestibility of rice was more affected by concentration than by amylose content, as well as by the degree of gelatinization due to structural difference.

• Korean journal of food and cookery science
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• v.1 no.1
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• pp.45-52
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• 1985

For the knowledge of characteristics of the cooking condition of different varieties of patato, 4 kinds of spring cultivated (Namjak, Sumi, Daiji, and Dowon) and 4 kinds of summer cultivated (Namjak, Sumi, Bintze, Radosa) were selected. The quality of potato starch, the viscosity, and the palatability of each potato soup were measured respectively. The amylograph characteristics of potato starch showed great difference not only between the spring and the summer cultivated, but also among the various kinds of potatoes. The amylograph of the spring cultivated didn't show the breakdown and the set back largely but showed the gradual increase of the viscosity and the high gelatinization temperature. Bintze and Namjak among the summer cultivated were gelatinized easily and in low temperature, and showed the beakdown. The low gelati-nization temperature of the summer cultivated infers that the starch granules of the summer cultivated are less compact then those of the spring ones. Sumi, Daiji and Dowon of the spring products showed the soup was falling down, but the viscosity of Namjak and 4 summer cultivated increased only slightly. The taste of soup is different according to the consistency of soup, and so the taste of soup of Daiji, Dowon, and Sumi of the spring cultivated products was good at the consistency 19.8％ and 23.5％. All the summer cultivated products and Namjak of the spring cultivated were good at 27％.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.613-618
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• 2013

The quality characteristics of brown rice polished with grains of four rice varieties (Hwaseonchal, Baegjinju, Ilpum and Goami) were examined. For the physical properties of native and fried brown rice starches, the gelatinization temperatures and enthalpies (determined with differential scanning calorimetry) of brown rice starches decreased with increasing amylose content. The pasting viscosities of native brown rice starches in distilled water were higher than those in $HgCl_2$ solution (as an ${\alpha}$-amylase inhibitor). The highest viscosity of gelatinized starch was observed for the starch of Ilpum rice variety relative to other varieties. Cystal packing arrangement of brown rice starches subjected to deep-fat frying converted A-type (typically observed for cereal starches) into V-type (formed by retrogradation and recrystllization of amylose molecules).

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.850-855
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• 1988

Rheological propreties of defatted and 1% palmitic arid reincorporated rice starch solutions were investigated, comparing with nondefatted starch. Flow behavior of gelatinized starch solutions(3-7%) revealed pseudoplastic behavior with yield stress, but yield stress was decreased by defatting. Relationship between logarithmic consistency index and concentration of nondefatted starch solution was linear with single slope, but the slopes for defatted and reincorporated starch solutions were different at 3-5% and 5-7% starch concentration. The activation energies for 7% starch solutions were estimated to be 3.14-4.76 kcal/g mol and increased slightly by defatting. All thre starch solutions above 4% concentration exhibited hysteresis phenomena, but by defatting, humping phenomena was observed and thixotropic behavior were increased slightly.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.504-510
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• 2018

Different processing methods, including steeping, boiling, roasting, and pressure roasting were used to deactivate anti-nutritional factors and remove off-flavor present in legumes. The physical and textural characteristic of cookie made with the treated flours were examined. The lightness of roasted cowpea flour was higher than that of the other treated legume flours, whereas that of pressure-roasted mungbean flour was the lowest. The boiled and pressure-roasted legume flours exhibited substantially lower pasting viscosity since the starches in these flours were considerably gelatinized during the heat treatment. Steeped mungbean flour had a significantly higher final viscosity than the other treated legume flours. Cookies containing mungbean flour had a higher protein content but lower lipid content than those containing cowpea flour. Cookies made with cowpea flour had a greater hardness than those made with mungbean flour. Cookies containing roasted flour had relatively better color properties than did those containing flours that were treated using other methods.

• Food Quality and Culture
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• v.3 no.1
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• pp.1-5
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• 2009

The objective of this study was to develop a reliable and reproducible descriptive analysis procedure for Korean style sweet pumpkin gruel (Hobakjuk). The sensory attributes of the sweet pumpkin gruel were developed and defined, the sample preparation method was standardized, and the sensory evaluation procedure for a sample was established. Seven types of sweet pumpkin gruel (five ready-to-eat type vs. two ready-to-heat type) were selected to be analyzed. Panel training and descriptive analysis were carried out with these 7 samples. A total of 12 sensory attributes (2 aroma/odor, 5 taste/flavor, 4 texture/mouthfeel, and 1 aftertaste attributes) were developed to describe the sensory characteristics of the sweet pumpkin gruel. The definition and reference standards for each sensory attribute were determined to clearly understand each attribute. In the main experiment, trained panelists evaluated the sensory characteristics of the 7 gruel samples based on a fifteen-point intensity scale using the developed attributes. The results were statistically analyzed by analysis of variance, principal component analysis, and cluster analysis. The results showed that the 7 sweet pumpkin gruel samples significantly differed in their intensities of all attributes except for sweet pumpkin aroma and viscosity. The ready-to-eat style samples were distinctly characterized by their sweet pumpkin aroma and flavor, whereas the ready-to-heat style samples were markedly characterized by their low intensity of gelatinized starch and pumpkin flavor retention.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.301-306
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• 1990

The Physical and chemical properties or dry acorn starch(DS), detannined acorn starch (DTS) and defatted and detannined acorn starch(Drn) were investigated. Ail acorn starch sample, observed by a scanning electron microscope, showed a hemispherical shape ud its size was about $5{\sim}10{\mu}m$ in diameter. It had a little change on the pasting temperature of DS, DTS and DFTS but peak viscosity of DTS was somewhat higher than that of n. Flow behavior of gelatinized starch pastes showed a pseudoplastic behavior and flow behavior index was lower than unit. The consistency coefficient showed concentraion and temperature dependency. The activation energies of DS, DTS and DFTS were $2.09{\sim}3.58Kcal/g\;{\cdot}\;mol and time dependent characteristic of acorn starch samples showed thixotrpic behavior.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.285-291
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• 2008

This study was performed to find out starch properties of rice grains in three varieties with different amylose content, Ilpumbyeo (non-waxy), Goami2 (high amylose), and Hwasunchalbyeo (waxy rice). There was no difference among physico-chemical characteristics of rice grains, but Goami 2 showed $2{\sim}3$ folds higher crude fat (1.36%) than Ilpumbyeo. Pasting properties of RVA showed the highest values of maximum viscosity, breakdown, and final viscosity in Ilpumbyeo. A similar chain length distribution of amylopectin was found in Ilpumbyeo and Hwasunchalbyeo, indicating that DP 12 had the highest distribution. Goami 2 had the highest distribution in DP 14, and showed the lower percent (14.1%) than other rice cultivars. Thermal properties of DSC showed that the values of Tc and Tp of Hwasunchalbyeo were similar to Ilpumbyeo, whereas a slightly higher Tc was observed. The absorbtion enthalpy was also the highest (11.1 mJ/mg) in Hwasunchalbyeo. Goami 2 showed higher To, but the lowest enthalpy (6.52 mJ/mg) compared to Ilpumbyeo (7.92 mJ/mg). Retrogradation properties, which were measured with the gelatinized rice sample used for DSC, and stored in $4^{\circ}C$ during 6 days, indicated that retrogradation absorbtion peak was the first peak at $52.6{\sim}55.2^{\circ}C$, and the second peak above $95^{\circ}C$. Retrogradation enthalpy of Goami 2 was the highest value (5.12 mJ/mg).

• Journal of the East Asian Society of Dietary Life
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• v.14 no.4
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• pp.370-378
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• 2004

The purpose of this study was to investigate the effect of added nutriprotein and rice powder as a plasticizer on physicohemical property, texture property of Backsulgi. In the physicochemical property, the content of proximate composition of nutriprotein was measured as 6.1% of moisture, 3.6% of carbohydrate, 84.3% of crude protein, 0.6% of crude lipid, 5.4% of ash. The raw material of rice powder was measured as 9.6% of moisture, 83.7% of carbohydrate, 6.0% of crude protein, 0.4% of crude lipid, 0.3% of ash. Swelling power and pore ratio of the control were 78.53% and 72.42%, and tended to increase as the amounts of nutriprotein and plastic rice powder increased. Aging by Avrami eguation retarded in Backsulgi added 10% plastic rice powder than rice powder Backsulgi. All the samples added 2, 4, 6, and 8% nutriprotein at the temperatures of 20 were more effective than others on aging. In texture properties, cohesiveness and springiness were not significantly changed by adding nutriprotein and not significantly changed during the storage period in all samples. Hardness and gumminess decreased by adding 2∼8% nutriprotein and increased during the storage period in all samples. Springiness and gumminess decreased by adding 40% plastic rice powder and increased during the storage period in all sample. Cohesiveness and hardness decreased by the increase of plastic rice powder. The texture characteristics by rheometer showed that Backsulgi with nutriprotein and plastic rice powder exhibited lower in hardness than the control, indicating that nutriprotein and plastic rice powder were effective in retarding retrogradation, which is better when storage time became longer.