• 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.

• Journal of Conservation Science
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• v.25 no.1
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• pp.39-47
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• 2009

This paper reports a study on physical properties of the traditional adhesives for developing natural adhesives. This is to certify that the superiority of tradition through systematic surveys and experiments as well. We used three kinds of starches differing fermentation time(7 years, 4 years 8 months, and 2 years 8 months) which are fermented from wheat flour starches. The amylose contents, total sugar contents, crystallinity, particle size and shape, viscosity, pH, and adhesive strength were examined. The effect of fermentation time on physical properties of fermented wheat flour were studied. It was found that fermentation time effect various physical properties such as total sugar contents, amylose contents, crystallinity, viscosity, and so on.

• Korean journal of food and cookery science
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• v.17 no.6
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• pp.598-603
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• 2001

Gel characteristics of potato starches which were prepared by steeping potato at 10$\pm$ 1$\^{C}$ and 25$\^{C}$$\pm$1$\^{C}$ incubator for 11days were investigated. Results of the instrumental test of potato starch gels showed significantly different strength, hardness, gumminess, chewiness, cohesiveness by steeping time. The light microscope and scanning electron microscope of starch gels showed three-dimensional network including macroporous structure by steeping. The syneresis of potato starch gel was decreased by steeping potato at 24 for 72 hours.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.644-651
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• 2009

This study was conducted to investigate the effects of steeping periods and temperatures of waxy rice on the microflora and enzyme activities of steeping water and waxy rice, as well as on the microscopic structures of waxy rice during the preparation of gangjung. When the steeping water was 15 and $35^{\circ}C$, yeast and lactic acid bacteria were the major microflora after 1 day. After 11 days, Lactobacillus spp. were the major bacteria, while Bacillus spp. were the primary microflora after 21 days. At $25^{\circ}C$ the primary species were Bacillus spp., Leuconostoc spp., and Bacillus spp. after 1, 11 and 21 days, respectively. The $\alpha$-amylase activity of steeping water increased proportionally with the increase of temperature and period, while the protease activity tended to increase for 11 days, but decreased at 21 days. The enzyme activities of the steeped waxy rice, especially the $\alpha$-amylase activity, decreased with higher steeping temperature, while the $\beta$-amylase and glucoamylase activity remained constant for up to 21 days. Observation using scanning electron microscopy indicated that intracellular cleavage of steeped waxy rice endosperm resulted in a rough surface morphology due to the exposure of polygonal starch granules. Tiny pinholes on the surface of waxy rice starch granules were also observed after steeping for 11 days.

• Journal of the Korean Society of Food Culture
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• v.7 no.4
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• pp.291-296
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• 1992

The effects of steeping time of glutinous rice and of beating time of the cooked rice on characteristics of Ganjung was examined. and the optimum conditions of traditional Gangjung preparation were determined. Moisture absorption of glutinous rice was the maximum at 2 hours of steeping in water and did not increase much after then. pH of the steep water was the lowest at 7 days of steeping and increased slightly thereafter. Reducing sugar content of the steep water increased as the steepting time was extended. Expansion ratio of Gangiung was the greatest with 5 days of steepting, and tended to decrease with longer beating time. Optimum conditions of Gangjung preparation was 7 days of steeping glutinous rice and 4 minutes of beating (40 times/min) the cooked rice.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.277-284
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• 2008

The objective of this study was to investigate the effect of soaking time on physicochemical properties of waxy rice, waxy rice flour and waxy rice starch. Waxy rice (WR), waxy rice flour (WRF), waxy rice starch (WRS) were soaked at $18^{\circ}C$ for 14 days and dried at $40^{\circ}C$. Dried samples were grounded and sieved using 180 mesh. Physicochemical properties of the three samples, such as swelling power, solubility, moisture sorption isotherms and pasting properties using rapid visco analyzer (RVA) and crystal pattern using X-ray diffractometer were determined. In all samples, soaking time greatly influenced moisture sorption isotherms but no typical pattern was shown. Swelling power was not greatly changed by soaking time in the three samples. Solubility increased with increasing soaking time in all three samples, indicating that some soluble particles were exuded during soaking. In RVA pasting properties, WR and WRF showed a similar pattern, while WRS showed different pasting properties, suggesting that rice protein plays a significant role in pasting properties. X-ray diffraction patterns of all three samples showed typical A-type crystal pattern suggesting that soaking did not affect crystalline region of samples.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.303-311
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• 2009

In this study, weakly cemented sand was cured at air dry condition with different periods (3, 7, 14, 21, 28 days) and its unconfined compressive strength was evaluated. As a result, the strength of specimens with low cement ratios such as 4 and 8% increases until 7 days curing but, after 7 days, their strength continuously decreases. The strength of specimens with relatively high cement ratios such as 12 and 16% increases up to 7 days curing and then stays almost constant until 21 days. After 21 days curing, their strength suddenly dropped down, which is much lower than the strength of 3 days curing specimen. A cemented sand and gravel called CSG, which is highly permeable, could be exposed to repetitive drying and wetting conditions due to rainfall or groundwater table change during curing. In this study, the weakly cemented sand is exposed to repetitive drying and wetting and then its unconfined compressive strength was evaluated. As a result, the strength of a specimen with 27 days drying condition following 1 day wetting was at maximum 35% lower than the one cured under 28 days drying. The strength degradation due to wetting decreases as a cement ratio increases. However, the strength of a specimen with repetitive drying and wetting increases as the number of wetting increases until 3 cycles. After 3 cycles of drying and wetting, the rate of strength increase decreases due to an insufficient water for hydration or stays constant. If the sufficient water supply is provided to cemented sand during curing, the target or design strength increase can be achieved. Otherwise, the strength degradation due to wetting should be considered at the design stage.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.464-470
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• 2009

This study was conducted to determine the optimal steeping period and temperature for Gangjung production, using response surface methodology based on the previously reported sensory characteristics. Five sensory attributes ('degree of expansion', 'sourness', 'butyric acid flavor', 'hardness' and 'degree of melting'), which showed high variability explained ($R^2$) and recognized to be important for the quality of Gangjung were selected for optimization. As a result, the optimal steeping temperature and period of waxy rice were determined to be $31.5^{\circ}C$ and 9 days, respectively.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.638-643
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• 1994

Gelatinization and retrogradation properties of modified starches which were prepared by steeping sweet potato at $40^{\circ}C$ for 2, 4, 7 and 10 days were investigated. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C\;and\;1.32\;cal/g$, respectively, but those of modified starch were increased by steeping. In gelatinization by alkali, starches with 2, 4 and 7 day steeping showed higher viscosities than untreated starch, whereas the viscosities of starches with 10 day steeping decreased. The clarities in paste decreased during storage in all starches and decreased in starches with steeping. The degrees of retrogradation by ${\alpha}-amylase-iodine$ method were higher in starches with steeping than untreated starch. The enthalpy of retrograded starches by DSC increased by steeping except 4 day steeping starch. The sweet potato extract containing sugar inhibited the retrogradation of starch paste and the degree were higher in residual starches than in untreated starch.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.207-212
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• 2002

This study was to examine the characteristics in the texture of acorn Mooks (acorn starch jelly) with different conditions to prepare acorn starch. By texture profile analysis, hardness and chewiness with 50% deformation were increased with increasing soaking days. Hardness of acorn Mook, measured by texture analyzer, showed significantly difference between the samples, and was closely related to the content of non-starchy substances and their intrinsic viscosity. The observation of microstructure through a scanning electron microscope (SEM) showed that acorn Mook showed finer and more fibrous structure than control(0-0), sample without soaking of acorn and sediments. Sensory characteristics of acorn Mook were affected by soaking treatment. The result of acceptance test on acorn Mooks indicated that the color and hardness increased with the increase of soaking days of acorn nuts and soaking times of sediments. There was a little difference between the samples in astringency taste. Their overall acceptability also increased except for 4-2 sample (i.e., soaking of acorn, 4 days; soaking of sediments, 2 times) and 4-3 sample (i.e., soaking of acorn nuts, 4 days; soaking of sediments, 3 times). As the results, the color, light brown, and the taste, a little astringency with consistency, were important factors of acorn Mook.