• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.428-438
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• 1995

The gelatinization properties of corn and waxy corn starch doughs were examined at various moisture contents, heating temperatures and heating times. The onset temperatures of gelatinization with 1% CMC using Brabender Amylograph were $64^{\circ}C$ for both corn and waxy corn starch. In the gelatinization properties using DSC, onset temperature$(T_o)$, maximum peak temperature$(T_p)$, completion temperature$(T_c)$ and enthalpy of the corn starch were $68.15^{\circ}C,\;74.01^{\circ}C,\;85.65^{\circ}C$ and $3.2\;cal/gram$ respectively. While those of the waxy corn starch were $68.24^{\circ}C,\;75.43^{\circ}C,\;93^{\circ}C$ and $4.2\;cal/gram$ respectively. In enzymatic analysis, when the moisture content increased from 36% to 52% and heating temperature from $60^{\circ}C$ to $100^{\circ}C$, 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 regression equations of gelatinization degree (Y) of starch dough in the range of $36{\sim}52%$ moisture content $(X_1)\;60{\sim}100^{\circ}C$ heating temperature $(X_2)\;and\;0{\sim}2.0$ min heating time $(X_3)$ were examined using response surface analysis. The regression equation of corn starch dough was: $Y=28.659+8.638\;X_}+15.675\;X_2+7.770\;X_3-1.620\;{X_1}^2+10.790\;X_1X_2-4.220\;{X_2}^2+0.510\;X_1X_3+1.980\;X_2X_3-6.850\;{X_3}^2\;(R^2=0.9714)$ and that of waxy corn starch dough was: $Y=32.617+12.535\;X_1+20.470\;X_2+8.608\;X_3+4.093\;{X_1}^2+13.550\;X_1X_2-4.467\;{X_2}^2+1.560\;X_1X_3+2.160\;X_2X_3-9.527\;{X_3}^2$\;(R^2=0.9621)$. As the moisture content, heating temperature and heating time increased, the reaction rate constant(k) of gelatinization increased. The greatest reaction rate constant was observed at initial 0.5 min heating time of 1st gelatinization stage. At the heating temperature of $90^{\circ}C$, gelatinization of starch dough was completed almost in the initial 0.5 min heating time. The reaction rate constant of waxy corn starch dough was higher than that of corn starch dough under the same gelatinization conditions. At the 52% moisture content, the regression equation between reaction rate constant(k) and heating temperature(T) for corn starch dough was $log\;k=11.1140-4.1226{\times}10^3(1/T)$ (r=-0.9520) and that of waxy corn starch dough was $log\;k=10.1195-3.7090{\times}10^3(1/T)$ (r=-0.9064).

• 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.

• Applied Biological Chemistry
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• v.18 no.2
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• pp.102-108
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• 1975

Acorn starch preparation and some of its characteric study were made. The results obtained were as follows. 1) Yearly production of acorn in Korea is amounted to be 1,200,000 l approximately. The content of its carbohydrate was found to be 72.8%, so that this would be considered as one of good resources of starch in our country. 2) The major moieties of tannin constituents of acorn were found to be the gallic acid, catechin and chlorogenic acid. 3) The type of acorn starch granules were short oval shaped having the diameters of that were in the range of $3.5{\sim}5.2{\mu}$ and $8.0{\sim}19.5{\mu}$, respectively. 4) Initial gelatinifalion teniperaiure of acorn starch was $62{\sim}64^{\circ}C$, similar to those of corn and wheat starch. 5) Alnylose content of acorn starch were 27.1%, which is lower than that of barley but higher than that of potato starch. 6) The raising power of the acorn starch was 12.4, which is higher than that of the potato starch but lower than those of common cereal starches. 7) The blue value of acorn starch was 0.43, similar to that of wheat starch and higher than those of wheat potato and rice starch but lower than that of barley starch. 8) The alkali number of the acorn starch was 11.03, similar to that of corn starch but higher than those of barley and rice starch.

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.126-133
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• 2015

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. This result is appeared equally at wheat, corn and sweet potato starch. At this study, we treated potato, wheat, corn and sweet potato starch by ohmic/conventional method and observed change of external structure by microscope and internal structure by X-ray diffractometer. Conventional heated at $55^{\circ}C$ potato starch was not external structural changes. But ohmic heated potato starch is showed largely change. Some small size starch particle were broken or small particles are made of larger particle together or small particles caught up in the large particle. Changes in ohmic heated potato starch at $60^{\circ}C$ was greater. The inner matter came to an external particle burst inside and only the husk has been observed. The same change was observed in the rest of the starch. The change of internal structure of potato starch was measured using X-ray diffraction patterns. There was no significant difference between ohmic and conventional heating at $55^{\circ}C$. But almost every peak has disappeared ohmic at $60^{\circ}C$. Especially $5.4^{\circ}$ peak to represent the type B was completely gone. When viewed from the above results, external changes with change in the internal crystal structure of the starch particles were largely unknown to appear. In conclusion, during ohmic heating changes of starch due to the electric field with a change in temperature by the heating was found to have progressed at the same time.

• Korean journal of food and cookery science
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• v.10 no.2
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• pp.87-93
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• 1994

The sensory and instrumental characteristics of defatted and lipid-reintroduced kidney bean, mung bean and corn starch gels stored for 3 hrs and 24 hrs at room temperature were investigated. In sensory evaluation of starch gels, acceptability was highly correlated with hardness, bend property, cohesiveness and springiness. Mung bean starch gels showed sinigficantly highest value and followed by corn and kidney bean starch gels. Generally as for these factors, defatted starch gels were higher than untreated ones. The properties of defatted and lipid-reintroduced corn starch gels were similar to those of mung bean starch gels. In instrumental analysis, hardness was more important factor than any other ones. Hardness showed significantly higher value in the other of mung bean, corn and kidney bean starch gels, but it was highest in defatted starch gels among all treated gels. Hardness and springiness of defatted and lipid-reintroduced corn starch gels were similar to those of mung bean starch gels. Hardness of 24 hr stored starch gels increased more than that of 3 hr stored ones, but other textural factors did not change.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.207-213
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• 2009

Starch serves not only as an energy source for plants, animals, and humans but also as an environmentally friendly alternative for fossil fuels. Progress in understanding of starch biosynthesis, and the isolation of many genes involved in this process have enabled the genetic modification of crops in a rational manner to produce novel starches with improved functionality. Starch is composed of two glucose polymers, amylose and amylopectin. The amylose and amylopectin ratio in starch affects its physical and physicochemical properties. Alteration in starch structure can be achieved by modifying genes encoding the enzymes responsible for starch biosynthesis and starch hydrolysis. Here, we describe recent findings concerning the starch modification in sweetpotato. Sweetpotato [Ipomoea batatas (L.) Lam] ranks seventh in annual production among food crops in the world as an important starch source. To develop transgenic sweetpotato plants with modifying starch composition, we constructed transformation vectors overexpressing granule bound starch synthase I and inhibiting amylopectin synthesis genes such as starch branching enzyme and isoamylase under the control of 35S promoter, respectively. Transformation of sweetpotato (cv. Yulmi) is in progress.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1749-1754
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• 2006

Two slaughter experiments were conducted to determine the effects of rumen escape starch, by altering dietary starch concentration and corn particle size, on ${\alpha}$-amylase activity in the pancreas and the small intestinal digesta of lambs. In experiment 1, 18 wether lambs (28.5${\pm}$1.6 kg) were fed low, medium or high starch diets for 35 d and slaughtered. Dietary starch concentrations linearly increased rumen escape starch (p<0.05). Pancreatic ${\alpha}$-amylase activity was lower (p<0.05) in lambs fed the low starch diet. When expressed per gram of digesta, ${\alpha}$-amylase activity was lower in lambs fed the low starch diet. However, expressed as total activity, ${\alpha}$-amylase in the digesta was greater in lambs fed the medium starch diet. In experiment 2, 12 wether lambs (23.5${\pm}$0.3 kg) were fed diets with finely cracked corn, coarsely cracked corn and whole corn. These dietary treatments continued for 35 d before tissue collection. Rumen escape starch increased with increasing corn particle size (p<0.05). ${\alpha}$-amylase activity in the pancreas and the small intestinal digesta was significantly greater (p<0.05) in lambs fed the coarsely cracked corn. These data suggest that increasing rumen escape starch results in a quadratic increase in total ${\alpha}$-amylase activity in the pancreas and the small intestinal digesta. Maximum ${\alpha}$-amylase activity is reached when rumen escape starch is about 100-120 g/d in 25-30 kg lambs.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.4
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• pp.1-8
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• 2013

High loading of printing and writing grades with fillers has many advantageous aspects in papermaking because it allows decreasing fiber use and reducing manufacturing cost. High loading technology, however, has some disadvantageous aspects as well. It decreases physical properties of papers, especially strength properties. The problem associated with high loading can be reduced by applying surface sizing starch solution onto paper surface. It is important to control the penetration of the surface sizing starch solution into paper web to obtain the desired property improvement. In this study, the effect of the addition of two polymers into starch solution on paper properties has been examined. PVOH and polyDADMAC were used as polymeric additives for surface sizing with oxidized starch. Viscosity of starch solutions and surface roughness of dried starch films on glass slides showed that some interactions between polymeric additives and oxidized starch have been occurred and the most extensive interaction with starch solution was obtained with high molecular weight polyDADMAC. Low molecular weight PVOH was most effective in improving folding endurance and internal bond strength. On the other hand, polymer addition showed no effect on surface strength of paper. This indicates that not the level of starch holdout but the bonding strength of starch itself has predominant influence on surface strength of paper.

• Korean journal of food and cookery science
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• v.15 no.2
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• pp.185-190
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• 1999

In order to develop the techniques for isolation and production of barley starch from Youngsan variety, optimum conditions of isolation processes of barley starch was investigated. The effect of steeping temperature and time in wet-milling process was examined and the results showed that optimal steeping temperature and time were 30$^{\circ}C$ and 12 hr. The barley starch isolated under these conditions contained 5.7% crude protein, 69% starch content and 83% white value by 100 mesh process. The optimum condition of alkali treatment was showed that concentration of NaOH and treating time were 0.2% and 6 hr, respectively. To remove the fat content of barley starch, after alkali process obtained barley starch with the addition of 10% (v/v) EtOH was attempted. As the result, the barley starch contained 0.1% of crude fat. Under the optimized isolation conditions, the barley starch finally contained 0.1% protein and 95% starch content. The isolated barley starch were superior to commercial corn starch in purity and white value.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1410-1414
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• 1999

The granular size and shape of durian seed starch were $2.0-10.0\;{\mu}m$ and oval and polygonal. Amylose contents of durian seed, corn, sweet potato and potato starch were 28.3%, 27.5%, 20.3% and 21.7%, respectively. Blue value of durian seed (0.370) higher than that of corn (0.368), sweet potato (0.332), and potato starch (0.338). Alkali numbers of durian seed, corn, sweet potato and potato starch were 7.39, 9.02, 7.08 and 5.43, respectively. Swelling power of durian seed starch was similar to that of sweet potato starch. X-ray diffraction patterns of durian seed starch showed an A-type crystalline structure. According to pasting properties by Rapid Visco-Analyzer, the gelatinization temperature of durian seed starch $(76.6^{circ}C)$ was higher than that of corn $(73.0^{circ}C)$, sweet potato $(72.3^{circ}C)$ and potato starch $(70.2^{circ}C)$. The breakdown of durian seed starch were lower than that of corn, sweet potato and potato starch.