• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.334-339
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• 1993

Physicochemical properties such as amylose content, swelling power, gelatinization and DSC of legume starches were investigated. The granule shape of legume starches was oval. The size of cowpea and mung bean were smaller than kidney bean and red bean. The amylose content of mung bean and kidney bean was larger and were $25{\sim}29%$. Swelling power of kidney bean starch was much lower than other starches in all temperature range. In gelatinization temperature by Brabender amylogram, red bean starch was low, but kidney bean starch was rather high. Amylographic hot-paste viscosity and set back of cow pea, mung bean and red bean starches were high. But those of kidney bean starch were very low. DSC results Indicated kidney bean starch gelatinized in higher temperature. From above results, row pea and mung bean starches were similar in granule size and shape, solubility and swelling power, amylogram, and DSC thermogram. But kidney bean starch was very different and red bean starch was slightly different with the physicochemical properties of cow pea and mung bean starches.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.19-24
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• 1971

The Korean rice, Nonglim # 6 was milled into brown rice and 92% polished one and packed with the kraft paper bags. The sample, bags were irradiated with the respective doses of 30, 50, 600 and 800 Krad and then were stored at $10^{\circ}C$ and 75% RH. Changes of fat acidity, amylase activity, viscosity of thus irradiated rice were examined during storage. The results were as follows. 1) Fat acidity increased slightly in the range of $30{\sim}50$ Krad but remarkably in the range of $600{\sim}800$ Krad. However, the rate of increase was low in comparison with the storage under the room temperature. 2) The amylase activity of both the low dose lot and the control decreased in the same rate during the storage. However the high dose lot had more remarkable decrease of the amylase activity from the beginning. 3) The viscosity by Brabender amylogram showed the slightly decreasing tendency in both the low $30{\sim}50$ Krad lot and the control lot of the polished rice powder during storage. On the other hand, the high dose lot of 600 or 800 Krad marked the similar decreasing rate but by far the lower values of the viscosity. 4) The results of the organoleptic test presented no differences between the low dose lot and the control lot, but the high dose lot and the control lot differed significantly only in the color.

• Journal of Ginseng Research
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• v.8 no.2
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• pp.135-152
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• 1984

Solubility and degree of swelling of the starch were about 15% and 30%, respectively when the starch in agueous solution was heated at 90$^{\circ}C$ for 30minutes. The starch showed no singnificant differences in the degree of swelling and soblubility with a growing period of ginseng. The starch was begun gelatinize at 50-55$^{\circ}C$ and completed at 65-70$^{\circ}C$ by the amy tical methods of X-ray diffraction, disappearance of crystalinity. Brabender angly lographic analysis and amylase digestion test. The maximum and minimum peak viscosities of 10% starch solution were 5.500 B.U and 1960 B.U, respectively. The starch showed no significant differences in pasting temperature, maximum and minimum viscosities on amylogram with a growing period of ginseng. The intrinsic viscosities of the starch and amylose were 0.54 and 1.5-1.9, respectively.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.415-420
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• 1985

In this study, changes in physical and chemical properties of glutinous rice during various soaking periods (0, 0.08, 1, 3, 5, 7, 10 days) were investigated in order to clarify the relations ship between soaking period and expansion volume in the preparation of Gang Jung. The longer the soaking period was, the greater the expansion volume of Gang Jung was. Higher maximum viscosity and breakdown in amylogram of glutinous rice flour were observed as the soaking period was increased, As the length of soaking period increased, hardness of glutinous rice and size of flour particle significantly decreased, while sweeling power and solubility of glutinous rice flour showed no significant difference. Increased length of soaking period was associated with higher fatty acidity, higher acidity of water extract and lower pH of glutinous rice flour. Control of flour particle size distribution resulted in significantly larger expansion volume of Gang Jung. Brabender's amylogram showed that the increase of expansion volume of Gang Jung associated with the increase of soaking period was related to the change of rheological properties of glutinous rice. It seemed that changes in viscometric properties of glutinous rice was attributed to the different flour particle size distribution resulted from changes in hardness of rice during soaking.

• Applied Biological Chemistry
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• v.35 no.2
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• pp.92-98
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• 1992

Some physicochemical properties and molecular structure of cow pea, mung bean and acorn starches(mook-forming starches) and red bean, wheat and sweat potato starches(mook-unforming starches) were investigated. Amylose contents of cow pea, mung bean and acorn starch were higher than the others. Cow pea starch was similiar to mung bean starch in gelatinization characteristics by Brabender amylogram but cold viscosity of red bean starch and peak viscosity of sweet potato starch were especially high. Whereas viscosity of wheat starch was low in whole temperature range. Amylose molecules of larger molecular size$(above\;5{\times}10^5\;molecular\;weight)$ of three mook-forming starches were more than shoes of red bean and wheat starch. Chain distribution ratios$(DP\;35{\sim}55\;to\;DP\;10{\sim}20)$ of cow pea, mung bean and acorn amylopectin were higher than thoes of red bean, sweet potato and wheat amylopectin.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.696-703
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• 1994

The purpose of this study was to investigate the gelatinization properties of potato starch heated with microwave. Two types of potato starches were prepared; In group A raw potato starch was heated with microwave and in group B potato starch was isolated from potato heated with microwave. Both groups were exposed to the microwave energy in a 560W, 2,450 MHz oven for 60, 120, 180 and 300 seconds. Gelatinization behaviour by DSC made a few differences according to the ratio of starch to water. As the microwave heating time took longer, gelatinization temperature and gelatinization $enthalpy({\bigtriangleup}H_1)$ were decreased in and melting $enthalpy({\bigtriangleup}H_2)$ was increased in group A. Whereas they were increased in group B. In both groups, maximum viscosity in gelatinization by Brabender amylogram was decreased by microwave heating. Then the peak of the maximum viscosity was shifted to higher temperature and cold viscosity was slightly increased. In group A, viscosity in gelatinization and light transmittance by NaOH was increased in initial stage and gel volume in gelatinization by KSCN was decreased. On the other hand, in group B, viscosity by alkali was slightly decreased, but light transmittance by NaOH was almost never changed. Gel volume is decreased like group A.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.189-195
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• 2002

Corn starch was modified by oxidation with sodium hypochlorite (NaOCl) as an attempt to expand the application of starches in food industry. Corn starch was oxidized with 0.25, 0.5, 0.75, 1.0 and 1.5% active Cl/g starch at pH 7.0 and $25^{\circ}C$ for 10 minutes. The size, shape and amylose content of oxidized starches were similar to those of native corn starch. As the extent of oxidation increased, solubility, swelling power and the amount of soluble amylose increased, X-ray diffraction patterns changed, and relative crystallinity decreased. In Brabender amylogram, oxidation did not chance the gelatinization temperature, but oxidized starches had a lower peak in viscosity and their cooled pastes gave less setback, compared with native corn starch.

• Korean journal of food and cookery science
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• v.6 no.3 s.12
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• pp.1-7
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• 1990

The physicochemical properties of acorn and chestnut starches were investigated. The shape of two starches granules was the rounded trianglar and some elliptical, but that of chestnut was less rounded. Water binding capacity of acorn was 191% and that of chestnut was 200%. Gel volume of chestnut started to increase from $55^{\circ}C$, and was higher value in all temperature range. Amylose of chestnut starch was leached more than that of acorn to $90^{\circ}C$. and reversely from $90^{\circ}C$ to $100^{\circ}C$. The blue value and amylose content of acorn and chestnut starches were 0.464, 0.440 and 24.8%, 22.5 respectively. According to Brabender Amylogram, gelatinization temperature and peak. hot and cold viscosity were $68.5^{\circ}C$, 1010, 910, 1470 BU for acorn and $63.7^{\circ}C$, 1480, 1000, 1080 BU for chestnut. Peak temperature and gelatinization enthalpy were $67.0^{\circ}C$ 3.64 cal/g for acorn, and $66.0^{\circ}C$, 2.82 ca1/g for chestnut. X-ray diffraction patterns of two starches were A-types but chestnut had some B-type character.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.532-536
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• 1995

Effect of water activity $(0.32{\sim}0.89)$ on the physicochemical properties of sweet potato starch during the storage for 5, 15 and 30 days at $40^{\circ}C$ was investigated. Shapes and sizes of starch granules were not changed. X-ray diffraction patterns of the starches appeared equally Ca-crystal structure. Sorption isotherm with storage day was sigmoidal. A slight loss of iodine affinity, increase in water binding capacity, and decrease in swelling power at $80^{\circ}C$ occurred as water activities increased. Viscosity pattern under Brabender Amylogram was not significantly changed with water activity, but initial pasting temperature decreased as water activity increased. The viscosity at $50^{\circ}C$, consistency and setback were increased with increasing storage day and water activity.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.99-107
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• 1984

Naked barley flour(Baekdong cultivar) was examined with respect to its pasting properties by means of Brabender amylograph after adding barley lipids, fatty acids, vegetable oils and emulsifiers at 1% level. Amylogram of barley flour showed a similar gelatinization temperature but higher paste viscosities at all reference points as compared with wheat flour. Barley flour showed lower amylograph curves by defatting with n-hexane, namely reductions in initial gelatinization point, maximum viscosity and setback value. But re-addition of n-hexane extract to the defatted flour essentially reproduced the curve obtained in the undefatted flour. Addition of polar and nonpolar lipids exhibited different effects on the pasting properties of barley flour. Polar lipids generally increased maximum viscosity a little while non-polar lipids increased the maximum viscosity substantially. Addition of increasing amounts of nonpolar lipids was found to progressively increase the maximum viscosity. Addition of fatty acids increaed th maximum viscosity and delayed the peak time. The maximum viscosity of defatted barley flour impregnated with unsaturated fatty acids was higher than that of defatted barley flour impregnated with saturated fatty acids Increasing amounts of linoleic acid were fount to progressively increase the maximum viscosity and to delay the peak time of defatted barley flour. Addition of six vegetable oils lowered the gelatinization temperature and rasied the maximum viscosity and temperature at maximum viscosity. Addition of increasing amount of peanut oil was found to decrease the maximum viscosity. The effect of emulsifiers was greater in undefatted flour than in defatted flour. The maximum viscosity of defatted flour was slightly affected by Methocel 50, Methocel 1500 and Emulthin, and substantially increased by Methocel 4000, sodium polyacrylate and calcium stearyl lactylate.