• Membrane Journal
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• v.8 no.3
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• pp.170-176
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• 1998

A study on the bioconversion of soluble starch to cyclodextrin(CD) homologue by CGTase was performed in the membrane-enzyme reactor equipped with a dead-end type membrane module. in the batch reactor, the total conversion of soluble starch to CD homologue was decreased rapidly from a maximum value of 45 % with increasing reaction time due to the product inhibition and breakdown of CD homologue to the reducing sugars. However, in the membrane-enzyme reactor, the total conversion of soluble starch was maintained at a constant value of 35 % throughout the reaction, since the membrane(MWCO = 10,000) promptly separated CD homologue from the reaction mixture. After the macdon for 24 hr in the membrane-enzyme reactor using a 10 % soluble starch solution, the cumulative production amount of CD homologue was about 3.7 kg/m$^2$ at the operating pressure of 2 atm.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.151-158
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• 2015

This study was conducted to know the variation and relationship of rice grain quality and starch pasting properties by transplanting times. Two early maturing rice cultivars which accounted for the most area of early maturing rice cultivar in Chungnam province were used. The experiment was laid out in a split-plot design with 3 replications. The main plot consisted of three transplanting times viz. early (April 25), ordinary (May 25) and late (June 25) with sub-plots containing two cultivars. According to the transplanting times, most of rice grain quality and starch pasting properties showed significant difference and Joami showed higher grain quality than Unkwang in all transplanting times. Especially, rice grain quality was improved when transplanted late, showing high head rice and glossiness of cooked rice due to the lower mean temperature during grain filling stage. Glossiness of cooked rice was positively correlated with head rice ratio, amylose content and setback value, and negatively correlated with chalky rice ratio and protein content. The highest positive and negative correlation were observed between breakdown value and peak viscosity ($r=0.98^{**}$), and breakdown and setback ($r=-0.94^{**}$), respectively. These results provide some information for rice researchers and producers producing cultivars with an improved quality, suggesting that rice quality is highly influenced by temperature at grain filling stage, and transplanting times is crucial in improving rice quality. In addition, starch pasting properties are useful for determining rice quality because rice grain quality and starch pasting properties are dependent on each other.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.451-456
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• 1984

Rheological properties of gelatinized rice starch solutions were investigated with Brookfield rotational viscometer. The 8% starch solution showed thixotropic behavior with yield stress. The alkali gelatinized starch was more thixotropic than the thermal gelatinized one. The time dependent characteristics of starch solutions followed Tiu's model. The value of rate constant $(a_1)$ in Tiu's model increased linearly with shear rate, and was exponentially dependent on concentration and temperature. Temperature dependency of rate constant and apparent viscosity followed Arrhenius type equation and the activation energy were about 14.3 and 6.8 Kcal/g mole, respectively. The $a_1-value$ was found to be useful to evaluate changes in structaral decay on the shearing time of gelatinized rice starch solutions.

• The Korean Journal of Food And Nutrition
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• v.31 no.1
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• pp.43-51
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• 2018

This study was conducted to investigate the quality of pumpkin paste added with different starches during storage at $4^{\circ}C$ for 8 days. Pumpkin paste was evaluated for pH, carotenoid, syneresis, color values, texture, and sensory characteristics. The properties of the pumpkin paste were studied on three different starches (CON: control, MCP: cow pea starch, MMB: mung bean starch, and MSP: sweet potato starch). The initial pH of the pumpkin paste with starches were 6.13~6.16. The pH of pumpkin paste increased as the starches added increased. The carotenoid content of CON was higher in the pumpkin paste processing. The change of syneresis significantly increased with the storage period, and the amount of change of MCP and MMB added with starch was smaller than CON without the added starch. The Hunter's L-values of the pumpkin paste increased, whereas the a- and b-value decreased as the amount of starches added increased. The results of the textural analysis showed that the hardness of MCP and MMB was different from that of other pumpkin paste, showing a lower value such as 38.26 g, 38.93 g, while CON and MSP was 40.43 g and 42.49 g, respectively. A sensory evaluation indicated that starches could enhance the overall texture characteristics of pumpkin paste. In terms of the overall acceptance of the pumpkin paste, the experimental group with MCP scored the best.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.428-435
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• 1994

Properties of modified rice starches prepared in drum drying and extrusion were evaluated to use for effective utilization. Blue value was the lowest (p<0.05) for waxy rice starch and L value was decreased after modification of starches. Water solubility index was the highest for modified starches prepared in extrusion, while water absorption index was the highest for modified starches prepared in drum drying. Cold-Water-Solubility was the highest (p<0.05) for modified rice starch prepared in drum drying (RD). Consistency index of RD was drastically increased as shear rate increased and yield stress was the highest for RD. Results of Gel Permeation Chromatography showed that starch components were broken down into lower molecular weight materials and amylose are degraded by modification. Changes in the X-ray diffrectometry pattern indicated the transformation of granule into an amorphous state during modification and illustrated V-type.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.1
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• pp.39-46
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• 2004

Waxy maize starches are inherently stable in soluble status and can be chemically modified to improve stability along with heat, acid and shear resistance. This study was carried out to investigate the effect of theological and sensory characteristics of the yellow layer cake made by adding different levels of waxy maize starch as a fat substitute for shortening. By increasing the substitution level of waxy maize starch for shortening, the specific gravity of cake batter increased and the viscosity decreased. The microstructures of cake crumb observed by the scanning electron microscope were not different significantly, and the size of air cells and fat particles also were not substantially decreased by increasing fat substitution level. The texture profile analysis using texture analyzer decreased by increasing the different substituting levels of waxy maize starch. Among various sensory properties, the color value of layer cake increased by increasing the level of waxy maize starch. However, the appearance, flavor, taste, texture and overall preference decreased.

• Korean journal of food and cookery science
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• v.6 no.2
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• pp.7-14
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• 1990

This study has been carried out in order to investigate the physicochemical properties of two small red bean starches. Some of rheological properties of the starch gels were also studied by experiments of various starch concentrations. Water binding capacity of black bean starch was 172.3% and that of red bean starch was 199.0%. Black bean starch had lower swelling power than red bean starch, but the solubility of the black bean starch was higher. When the temperature increased from 60$^{\circ}C$ to 70$^{\circ}C$, the transmittance of two starches rapidly increased. The gelatinized temperature in DSC for black bean was 66.2$^{\circ}C$ and that for red bean was 66.0$^{\circ}C$. Black bean and red bean starches had the blue vlaues of 0.55 and 0.56 and the alkali numbers of 4.40 and 4.13. The molecular weight of amylose was 40,000 and 33,611. The amylose contents of two starches were same at 52%. Brabender Amylographs of two small red bean starch pastes showed C pattern, which is stable. The results of compression test pointed out that TPA parameters varied with the change of storage time, and black bean starch gels had the higher TPA value. The retrogradation study by glucoamylase digestion method revealed that red bean starch gels were more easily retrogradated than black bean. X-ray diffraction patterns of two small red bean starches were A pattern, and diffraction peaks disappeared with gelatinization of starches.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.779-787
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• 2018

The objective of this study was to investigate the structural and physicochemical properties of starch by barely cultivars. Hwanggeumchal had a moisture content and ${\beta}$-glucan content of 12.02 and 6.23%, respectively. Hyegang had higher protein contents than those of the other cultivars. As a result of observing the particle size of starch, Hwanggeumchal and Hyegang had smaller particles of starch compared with the other cultivars at 15.7 and $15.9{\mu}m$, respectively. The analysis results on the content of damaged starch showed that Dahan and Hyegang had a damaged starch content of 1.14 and 1.20%, whereas Boseokchal and Hwanggeumchal were 0.76 and 0.49% respectively, showing low waxy cultivars. As for the content of amylose, the results show that Dahan and Hyegang had an amylose content of 37.07 and 37.75%, and Boseokchal and Hwanggeumchal were at 11.22 and 37.75%, respectively. As for the degree of amylopectin polymerization, all four cultivars had the highest degree of polymerization (DP) content of 13 - 24 at more than 54%, whereas the DP content ${\geq}37$ was the lowest at less than 5.35%. The results for the soluble and resistant starch content show that the content of soluble starch ranged from 93.90 to 95.76%, and resistant starch was 0.17 - 0.40%. After analyzing the gelatinization properties of barley starch, the value of the setback was low in Hwanggeumchal and Hyegang; thus, it is considered that the aging process of those cultivars will be slower than that of the others.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.377-383
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• 2003

The functional Jeungpyuns with dietary fiber containing cereals such as brown rice and barley flour were developed and physiochemical properties were investigated. The water binding capacity had significantly the highest value of 28.4% in raw rice flour, followed by brown rice flour and barley flour. The lowest reducing sugar value was seen in unpolished rice substituted Jeungpyun with value of 5.420 (P<0.05). The amount of reducing sugar decreased slightly after steaming, due to the increased degree of sugar dissociation. The L value of the lightness decreased significantly with the substituted samples (P< 0.05). The barley substituted samples were darker than that of brown rice sample groups with less green and yellow color. Microstructures of starch particles after fermentation showed completely dispersed starch particles with air bubbles and sponge-like structure in all samples after steaming. Thus, functional Jeungpyun replaced with brown rice and barley flour can be successfully formulated and has been influenced by the physicochemical properties.

• Korean Journal of Human Ecology
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• v.17 no.1
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• pp.151-158
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• 2008

This study examines the cooking quality, rheology, and sensory characteristics of ramyon noodles made from Korean wheat and arrowroot starch. The control was made from Australian standard wheat(ASW) and the sample was made from Korean wheat. The ratios of arrowwood starch in the sample group were 0%, 5%, 10%, 15%, 20%, 25%, and 30% respectively, and the result was as follows: the yield of the arrowwood starch was 18.8% and moisture level was 14.2%. The lightness(L), redness(a), and yellowness(b) of ASW were 92.07, 1.44, 10.22 respectively, whereas those of Korean wheat were 92.05, 1.55, 11.01, which means the two kinds of wheat showed very little difference in lightness, but Korean wheat had higher degrees of a and b than ASW. The color value of arrowroot starch is L 72.65, a 3.44, b 12.92, so it has a lower degree of lightness and higher degrees of a and b than two kinds of wheat. Dried ramyon displayed a lower degree of lightness and higher degrees of a and b than cooked ramyon, but the first decreased and a increased as we increased the ratio of arrowroot starch in it. The weight of dried ramyon did not show a significant difference among the groups. On the other hand, the weight, volume, water absorption, and the turbidity of cooked ramyon increased as we increased the amount of arrowroot starch in it. The maximum weight, solidity, and elasticity of the control group were greater than those of ramyon made from Korean wheat, but its brittleness was lower. The two groups showed the same degrees of hardness, adhesiveness, and cohesiveness. The maximum weight, solidity, and adhesiveness of the control group increased as we increased the amount of arrowroot starch in it, and the hardness and brittleness were great when the ratio of arrowroot starch was 20%; elasticity was greatest when the ratio of arrowroot starch was 15, 20, and 25%; its adhesiveness and cohesiveness did not depend on the amount of arrowroot starch in it. In the sensory characteristics evaluation, the items that showed significant differences include: appearance (p<0.01), color(p<0.01), smell(p<0.001), transparency(p<0.05), and overall acceptability(p<0.05). The ramyon earned the highest score in appearance when the ratios of arrowroot starch were 5%, 15%, and 20%. As for color and smell, it earned the highest score when it contained 20 and 25% of arrowroot starch. The transparency decreased as we increased the amount of arrowroot starch, and overall acceptability was highest when the ratio of arrowroot starch was 15%. There was a significant difference in overall acceptability between the control and the sample group. As for the loosing speed and chewiness, there was no significant difference between the two groups. When we look at the result of various tests to evaluate the cooking quality, rheology, and sensory characteristics of ramyon noodles, ramyons that contained 15 to 25% of arrowroot starch earned the high scores, and of these the one with 20% of arrowroot starch earned the highest score on all accounts.