• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.552-557
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• 1996

Gels of rice starches isolated from jinmibyeo, llpoombyeo and Dongjinbyeo were prepared with $60{\sim}65%$ water content (based on the total weight) and stored at $-18^{\circ}C,\;4^{\circ}C,\;20^{\circ}C,\;30^{\circ}C,\;and\;37^{\circ}C$ for 6 days. The effects of varieties, water content and storage temperature on the degree of retrogradation (DR) of gels were measured by ${\alpha}$-amylase-iodine method. DRs of rice starch gels increased rapidly during the initial stage of storage, but slowly after that. DRs were highest with 60% water content and lowest with 65% water content at any storage temperature. Regarding the storage temperature, DRs of gels increased in the following order : $4^{\circ}C>20^{\circ}C>30^{\circ}C>37^{\circ}C>-18^{\circ}C>$. As the storage temperature was increased, DR per $10^{\circ}C$ increased above refrigerated temperature decreased in the following order : jinmibyeo>llpoombyeo>Dongjinbyeo.

• Applied Biological Chemistry
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• v.40 no.4
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• pp.289-293
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• 1997

The effects of different types of additives(sucrose fatty acid ester(SE), oligosaccharide and alum) on 40% nonwaxy rice starch gels stored at $20{\pm}1^{\circ}C$ were investigated by ${\alpha}-amylase-iodine$ method, X-ray diffractometry and differential scanning calorimetry. The addition of SE retarded the retrogradation of gels throughout storage period and the antistaling effect of SE was increased with increasing concentration. Oligosaccharide(0.1%) inhibited the retrogradation, but oligosaccharide(0.1% or 0.5%) retarded the retrogradation at early stage of storage, and stimulated the retrogradation after 3 days. Alum of 0.1% level retarded the retrogradation, but 0.3% level activated the retrogradation after 24 hours and 0.5% level did after 12 hours. The effect of additives on the retrogradation of rice starch gels showed the different tendencies at the level of additives. On 0.1% level, the effect of those was similar but on 0.5%, the degree of retardation increased in order of oligosaccharide, SE1170, alum, no addition for up to 2 days of storage and SE1170, no addition, oligosaccharide, alum for 3 days of storage.

• Applied Biological Chemistry
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• v.25 no.2
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• pp.67-74
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• 1982

Morphology, physicochemical properties, pasting properties in the presence of various anionic ions and aging of gels of Akibare (Japoica type) and Milyang 23 (Indica type) rice starch were studied, Both starches. were polygonal with length in the range of $3{\sim}6{\mu}m$. Starch granules of Akibare were somewhat smaller than those of Milyang 23. X-ray diffraction study demonstrated that peak shape and intensity were significantly different between the two starches. Akibare and Milyang 23 rice starch had amylose content of 18.5 and 19.5% and water binding capacity of 106 and 100%, respectively. Milyang 23 rice starch had a higher swelling power than Akibare starch. A relationship between percent solubility and swelling power implied that bonding forces within the granules of the both starches were different. The optical transmittance of 0.1% suspension of the two starches increased rapidly from $60^{\circ}C$. In the range of $60{\sim}90^{\circ}C$, the two starches showed a single gelatinization pattern. Amylograms of the two starches in the presence of various anionic ions showed that pasting temperature and peak temperature were progressively increased in the order of SCN-${SO_4}^=$. SCN- and I- ions increased the peak height of Akibare rice starch while only SCN- ion was effective for Milyang 23 rice starch. There were no differences in the rates of retrogradation of 45% gels of the two starches stored at $21^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.157-161
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• 1978

Physicochemical properties of rice starches from Paldal(japonica type) and Tongil(indica type) were investigated. There were no significant differences in water-binding capacity, blue value and amylose content between the two starches. Paldal starch showed a higher value for-swelling power than Tongil starch. Amylograph data showed that both Paldal and Tongil starches had similar paste viscosities except setback in which Tongil starch showed a higher value. No significant differences were observed for intrinsic viscosity and glucose units per segment between Paldal and Tongil amylopectin fractions. However, the intrinsic viscosity for Tongil amylose was considerably higher than Paldal amylose. The rate of retrogradation of Tongil starch gels at $21^{\circ}C$ was faster than Paldal starch gels.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.876-881
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• 1997

The relationship between the molecular structure of acid-hydrolyzed rice starch and the retrogradation rate of starch gel was investigated. The molecular structure of starch was modified by acid hydrolysis with 1 N HCl at $35^{\circ}C$. The molecular weight of starch decreased as acid hydrolysis time was increased. At the early stage of hydrolysis up to 3 hr, the branching point of amylopectin was degraded and thereafter both ${\alpha}-1,4\;and\;{\alpha}-1,6$ linkages were hydrolyzed. The starch gel (50%) stored at $20^{\circ}C$ revealed that the rapid retrogradation occurred during 4 hr of storage which was more pronounced as the hydrolysis time increased. The degree of retrogradation of starch gels after 4 hr storage showed a linear relationship with the yield of hydrolyzate. These results suggested that the retrogradation of starch gel was accelerated by degradation of ${\alpha}-1,6$ linkages with acid.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.157-163
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• 2002

The gelatinization and retrogradation properties of rice starch added with dietary fibers from sikhe were investigated. The pasting temperature and setback of starch measured by using a rapid visco analyzer were increased by the addition of the fiber, whereas the peak viscosity, trough viscosity, end viscosity, breakdown and consistency were lowered. The onset temperature of starch measured by a DSC was increased, but the enthalpy of gelatinization of the starch was decreased as the addition of fiber increased. The melting peak temperature of the retrograded starch gels was 41∼46$\^{C}$ as measured by a DSC. The melting enthalpy of the control retrograded starch gel was increased while storing for 1, 3 and 7 days at 4$\^{C}$, but that of containing sikhe fiber showed no differences.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.766-771
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• 1989

physicochemical properties of rice starch isolated from eight varieties were examined to evaluate the rice processing suitability The amylose contents of rice starch were varied with 16.7-29.7%, and IR 30, Godael, Aguja and Lengkwang varieties showed higher amylose content than the other varieties. The water binding capacity and blue value were in the range of 87.0 103.0 and 0.178-0.305, respectively. As the amylose content increased, the amylogram pasting temperature and the break down ratio increased, while the peak viscosity did not show any significant difference. The transmittance of 0.1% starch suspension slowly increased at $50^{\circ}C$ in the low-amylose content rice group, and rapidly increased at $65^{\circ}C$ in the high-amylose content rice group, but there were no differences above $75^{\circ}C$ among varieties. Also the low-amylose rice starch showed higher values in the swelling power and solubility. The hardness of the 30% rice starch gels was low in low-amylose one. During storage at $20^{\circ}C$ for 14 days, the increment of hardness was more slow in high-amylose one. The retrogradation velocity constant of rice starch gel by Avrami equation was the highest as 0.219 in Aguja variety.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.157-166
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• 1997

Studies were carried out to investigate formation of Mook and its physical properties as well as the effects of amylose and amylopectin on the texture of Mook which were made from cowpea, mung bean, acorn, buckwheat, kidney bean, potato, rice, corn and wheat starches. Texture parameters of 10% starch gels were significantly different depending on the kind of starches. However, there were no significant differences in those of gels of starches commonly used for the preparation of mook. It was appeared that gel indices of cowpea, mung bean, acorn and buckwheat starch gels were in the range of 2.11-2.37, elastic limits were more than 0.60, gel strength coefficients were in the range of 700-1400 and brittlnesses were 0.23-0.62. It was also appeared that gel index and elastic limit were affected by amylopectin and gel strength coefficient and brittleness, by amylose, and that these two fractions were not able to form gel like Mook unless they were combined with proper proportion. Effect of addition of amylose from cereal and potato starches to cowpea starch or cowpea amylopectin were different from that of cowpea amylose. When cereal starches were supplemented by cowpea starches, gel strength coefficients and brittlenesses of their gels were increased, but gel indices and elastic limits were not changed. However, potato starch gel was improved to be similar to Mook with increasing of gel strength coefficient and appearance of brittleness by addition of cowpea amylose.

• Korean journal of food and cookery science
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• v.33 no.1
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• pp.87-93
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• 2017

Purpose: Rice starch is known not to be suitable to Mook. Its gel is not hard and elastic enough and too sticky. This study investigated the effects of agar, carrageenan, and gelatin addition on low amylose rice flour paste and gel properties for making Mook. Methods: Angemi, low amylose rice, and Goamibyeo, intermediate amylose rice, were dry milled. The properties of Mook were determined by texture profile analysis (TPA), cold storage stability, and sensory acceptance. Results: Addition of agar and carrageenan increased cold paste viscosity, whereas addition of gelatin decreased cold paste viscosity while improving breakdown and setback viscosity. When 30% of gelling agents such as agar, carrageenan, and gelatin were added to low amylose rice, Angemi, Mook-like gels were formed. The hardness, adhesiveness, and springiness of gelling reagent-added Angemi Mook increased, whereas cohesiveness decreased, and fracturability was not observed. The addition of gelling agent decreased lightness and increased yellowness. Angemi Mook added with gelatin showed the best freeze-thaw stability while addition of agar and carrageenan increased syneresis. The carrageenan-added Angemi Mook was equal to Goamibyeo 100% Mook in all sensory acceptance properties without significant difference. Conclusion: Above results suggest that addition of carrageenan and gelatin to low amylose rice can be used to produce Mook with improved physical properties.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.690-696
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• 1995

Properties of dry milled rice flours made of paddy with different moisture content (12.6, 18.4 and 24.4%) were compared with those of wet milled rice flour. Among dry milled rice flour, the higher moisture content of paddy the finer particle size and the more distinct shape of starch were observed. As the moisture content of paddy increased, L (lightness) value and water absorption index of rice flour were increased, while setback in amylogram and water soluble index were decreased. Lower gel consistency and gel strength were found in dry milled rice flours than in wet milled rice flour, while no significant difference was found among dry milled rice flours. Enthalpy for melting crystalline of retrograded gels was higher in dry milled rice flours made of paddy with 24.4% moisture content than in other dry milled rice flours. Wet milled rice flour had lower retrogradation enthalphy than dry milled rice flours.