• 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.

• Current Research on Agriculture and Life Sciences
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• v.29
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• pp.1-10
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• 2011

This study was conducted to determine the agronomic characteristics of low amylose lines which were derived from induced mutants by T-DNA insertion. The agronomic and physicochemical properties of the low amylose mutants were analyzed and compared with a donor cultivar 'Dongjin' and a low amylose cultivar 'Baekjinju'. The heading date of the low amylose mutants was similar to the donor cultivar 'Dongjin' and yield index of the mutants was 78~92% compared with 'Dongjin'. The amylose content of four mutants in brown rice was ranged from 16.1 to 16.7%. Among low amylose mutants, 'P50-4-4-5' was lower 3.6%(13.3%) than those of 'Dongjin'(16.9%) in amylose content of milled rice. The grain length of 'P50-4-4-5' was similar to the donor cultivar, however, thousand grain weight(18.9g) was lighter than those of 'Dongjin'. The score of alkali digestion in brown rice of 'P50-4-4-5'(5.5) was lower than that of 'Dongjin'(6.8) and similar to 'Baekjinju'(5.8). The gel consistency of 'P50-4-4-5'(84mm) in milled rice exhibited that was longer than 'Dongjin'(76mm) and 'Baekjinju'(81mm). The result of eating quality showed that 'P50-4-4-5'(78.8) was higher than those of 'Dongjin'(60.3) and 'Baekjinju'(67.2). Thus our data suggest that 'P50-4-4-5' will facilitate the development of a new cultivar with low amylose rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.129-133
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• 1974

In order to obtain the fundamental informations on the protein and amylose content in rice grain, 4 varieties were subjected to the 4 different shortday treatments in 2 kinds temperature. Results can be summarized as follows; 1). By warmer temperature amylose content in the rice dropped by 2 to 3%, but no significant changes in protein content. 2). Short-day treatment caused decreases in amylose content by 2 to 5% and increases in protein content by 2 to 6%. 3). Interactions among varieties, temperature and shortday was significant for both the amylose content and protein content.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.31-31
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• 2018

The purpose of this study was to statistically analyze amylose and protein content of rice variety resources collected from China (1,542), Japan (1,409), Korea (413), and India (287). The statistical analysis was conducted using ANOVA and DMRT based on the data obtained from NIRS analysis. The average amylose contents were 18.85% in Japanese, 19.99% in Korean, 20.27% in Chinese, and 25.46% in Indian resources. The average protein contents were 7.23% in Korean, 7.73% in Japanese, 8.01% in Chinese, and 8.17% in Indian resources. The amylose and protein content using ANOVA showed significant differences at the level of 0.01. The F-test for amylose content was 158.34, and for protein content was 53.95 compared to critical value 3.78. The amylose and protein content using DMRT (p<0.01) showed significant difference between countries. The value of statistical treatment was divided into three groups such as $China^a$, $Korea^a$, $Japan^b$, $India^c$ in amylose and $China^a$, $India^a$, $Japan^b$, $Korea^c$ in protein. Japanese resources had the lowest level of amylose contents, whereas, the lowest level of protein content was found in Korean resources compared to other origins. Indian resources showed the highest level of amylose and protein contents. It is recommended that these results could be helpful to future breeding experiments.

• Food Science and Preservation
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• v.11 no.4
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• pp.496-502
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• 2004

Purified acorn starch was obtained from alkali precipitation method. Acorn amylose and acorn amylopectin were fractionated from purified acorn starch by butanol improvement method. Gel permeation chromatography (GPC) was used to measure molecular weight distribution of acorn starch, acorn amylose, acorn amylopectin and corn starch, corn amylose, corn amylopectin. GPC measurement diagrams were obtained by each retention time. And then, we used DMSO and DMF as solvent, pullulan as standard material. We calculated the Number-average molar mass (Mn), Weight-average molar mass (Mw) and polydispersity from molecular weight distribution of each sample. As a result of estimating molecular weight using GPC, Mw of amylose has small value than Mw of amylopectin. From this fact, the molecular structural aspects of amylose and amylopectin were predicted and it was in good agrement with the tendency of polydispersity by GPC. The polydispersity of starch had big value than amylose and amylopectin, from this result, it might be known that the range of molecular weight appeared broad by heterogeneous properties of two components. The viscosity of purified acorn starch, amylose, amylopectin seperated from acorn starch, was decreased by increasing the shear rate and raising the temperature exponentially. Acorn starch solutions exhibited pseudoplastic power law fluid behavior.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.590-595
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• 1998

Seven varieties (Suweonjo, Suweon232, BG276-5, IR44, IR41999-139, Suweon230 and Yongjubyeo) of rice were used to study for making rice bread by amylose content. Suweonjo had the highest amylose content (27.07%) and Yongjubyeo had the lowest one (17.17%). Suweonjo showed the highest volume after baking, while Yongjubyeo the lowest volume one. Volume and hardness of the rice bread decreased as amylose content decreased. The amylose content was not associated with hardness and color values of rice bread after baking. Sensory evaluation for internal parts of rice bread showed that score of air cell, color of crumb, aroma, taste, chewability and texture decreased as amylose content increased, while volume of rice bread increased. The low-amylose rice cultivar revealeded better suitability for rice bread.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.39-42
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• 1990

The properties of amylose of cow pea starch were investigated. Amylose content of cow pea was 25.1 % and iodine binding capacity was 20.2 %. The ${\beta}-amylolysis$ limit of the amylose was 82.3%. The limiting viscosity number of the amylose fraction was 204 ml/g and the corresponding average degree of polymerization was 1,510 glucose units. The percent distribution of molecular weight of the amylose by gel chromatography was $1{\times}10^4$(0.7 %), $1{\times}10^4{\sim}4{\times}10^4$(4.1 %), $4{\times}10^4{\sim}5{\times}10^5$(44.6 %), $5{\times}10^5{\sim}4{\times}10^7$(49.6 % ).

• The Korean Journal of Food And Nutrition
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• v.16 no.2
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• pp.105-110
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• 2003

The effect of varietal differences of rice starches by amylose content and gel consistency on the retrogradation behavior was studied. The gel consistency test, which is designed to detect differences in the texture of cooked rice of varieties that have a similar amylose content, had been turned out to be useful in this study. Both Suwon 232 and San Li Cun had higher amylose content, but were greatly different in gel consistency values. The results showed that setback viscosity of rice flour measured in a Brabender amylograph was significantly affected by amylose content as well as gel consistency. Increase in the rigidity modulus (E) of rice starch gels during storage determined by using Texture analyzer indicated that amylose content was an important factor in terms of hardness development The study of Avrami kinetics of retrogradation showed that time constant of rice starch gels was influenced by amylose content, but not by gel consistency.

• The Korean Journal of Community Living Science
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• v.17 no.2
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• pp.61-68
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• 2006

This Study was conducted to investigate the processing quality of high-amylose content rice(goami) flour for noodle. The potassium and magnesium contents of rice flour were negatively associated with gross score of noodle making mixed with wheat flour. The high-amylose content of rice flour was closed associated with gel consistency negatively and with hardness of rice noodle positively, Setback viscosity of rice flour measured in a rapid visco-analyser(RVA) was significantly affected by amylose content as well as gel consistency. Also the amylose content decreased, the amylogram pasting temperature and the breakdown ratio increased. The low-amylose content rice(Chucheong) flour showed higher values in solubility. Cooking quality and texture were measured, and sensory evaluation was performed with the noodles prepared. Texture measurement showed that the noodles of composite flour containing 40% goami rice flour were superior to those wheat flour alone. Water binding capacity of the composite flour containing 40% goami rice flour was lower than that of 40% chucheong rice flour. In sensory evaluation, chewiness, overall acceptability of noodle with 40% goami ricer was evaluated as the best.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.264-269
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• 1993

Molecular structural properties of legume starches were investigated. In intrinsic viscosity and degree of Polymerization of amylose and amylopectins, cow pea and mung bean were high, but kidney bean was low. Low molecular weight fractions for kidney bean starch were much eluted by gel chromatography. In the elution profiles of their amylose by Sepharose 2B-CL, molecular weight of kidney bean amylose was smaller than that of other amylose Molecular weights of cow pea and mung bean amyloses were large, but that of kidney bean amylose was small and red bean amylose was medium. The elution profiles by Sephadex G-50 after debranching amylopectins with pullulanase showed similar patterns.