• Journal of the Korean Home Economics Association
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• v.39 no.1
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• pp.103-111
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• 2001

This study was attempted to investigate the effect of partial replacement of rice flour with black or brown rice flour on texture properties and retrogradation of Julpyun(Korean rice cake). In sensory evaluation, the Julpyuns replaced black or brown rice flour 20% had high score in color, flavor and overall acceptability not including mouthfeel. As the result of the measurement with texture analyzer, hardness, gumminess and chewiness of Julpyuns tended to decrease in proportion to the amount of black and brown rice flour in the formula. These resets implied that the degree of retrogradation of black and brown rice Julpyuns might be low. Julpyuns replaced with black rice were a little lower than those of brown rice in the hardness. In the retrogradation speed by Avrami,s equation, the rate constants of Julpyun replaced black and brown rice flour was lower than that of milled rice, restating in delay in firming.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.500-506
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• 2000

The effects of sodium stearoyl lactylate(SSL) on the thermal properties of wheat starch and amylopectin, and the crystallinity properties of amylopectin were investigated using differential scanning calorimetry(DSC) and X-ray diffractometer. On the rescan(second heating), amylopectin produced the featureless thermogram shown at the second heating, and SSL alone melted at $40{\sim}55^{\circ}C$, while the mixture of amylopectin containing 8% water and SSL(10:1), presenting the evidence of AP-SSL complex, showed differentiate melting temperature(other crystallinity) from SSL alone. Also, the melting enthalpy of AP and SSL mixture by subsequent heating and cooling were continuously increased. Further, the mixtures of wheat starch: SSL (5:1, w/w) and amylopectin: SSL(5:1, w/w), indicated AP-SSL complex, showed the reversible melting peak at temperature range of $60{\sim}70^{\circ}C$ together with melting peak of SSL observed at temperature range of $40{\sim}55^{\circ}C$. AP-SSL complex in the X-ray diffraction, compared V-form of amylose-lipid complex, exhibited characteristic peaks($2{\theta}$, 5.57, 20.903, 23.227). The gelatinization enthalpy value of wheat starch in the presence of SSL, observed at temperature range of $50{\sim}70^{\circ}C$, was decreased at total water content 60%, whearas had no significant effect at total water content 40, 50%, and also, SSL increased melting enthalpy of amylose-lipid complex. The extent of AP and wheat starch retrogradation wasreduced significantly by SSL.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.838-842
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• 2006

Gum was added to Jeungpyun (steamed Korean rice cake) to extend the shelf life and prevent retrogradation. The hardness of Jeungpyun was analyzed and the type of retrogradation was calculated by the Avrami equation. Guar gum, xanthan gum and pullulan were added to the steamed Korean rice cake at contents of 0.05%, 0.1% and 0.5% (w/w). The moisture contents of the steamed Korean rice cake stored at $4^{\circ}C$ remained unchanged over the three days. When the concentration of added gums was less than 0.1 %, the hardness was lower than that of the non-added gum. At a gum concentration of 0.5%, the hardness of Jeungpyun with added guar gum and xanthan gum was higher than that of pullulan and non-added Jeungpyun. The types of retrogradation varied according to the amount and the kind of the added gums. The type of retrogradation of pullulan-added rice cake was similar to that of xanthan-added rice cake. The Avrami exponent of pullulan-added and xanthan-added Jeungpyun was 1.4${\sim}$1.49 and 1.25${\sim}$1.43, respectively. As the concentrations of pullulan were increased from 0.05% to 0.5%, the time constant (1/k) increased from 5.37 to 15.65. Pullulan and xanthan gum were confirmed to be more effective than guar gum for preventing the retrogradation of the steamed Korean rice cake known as Jeungpyun.

• Korean Journal of Food Science and Technology
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• v.18 no.6
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• pp.421-426
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• 1986

The carbohydrate characteristics and storability of two Korean traditional confections Seban-kangjeong (a Korean fried waxy-rice cookie) and starch-dashik (a Korean pressed starch cookie) were studied as compared with two Western confections fried cookie and biscuit. Seban-kangjeong showed lower contents of starch and sucrose and higher content of reducing sugar whereas starch-dashik showed higher contents of starch and sucrose and lower content of reducing sugar. Moisture content was higher in Korean confections than in Western confections. The degree of gelatinization was higher in Seban-kangjeong and fried cookie which were made through a frying process. Moisture adsorption isotherms were constructed for the four products. In storage test for 6 months under different temperature and humidity conditions, the relative humidity maintaining the initial moisture content of products was 68% for Seban-kangjeong and starch-dashik and 20% for fried cookie and biscuit. The ratio of retrogradation in storage was 15% in Seban-kangjeong, 20% in starchdashik and 28% in fried cookie and biscuit, showing the lowest progress in freezer storage.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.164-170
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• 1999

This experiment was carried out to elucidate change of antioxidant enzymes activities subjected to water stresses in soybean plant. In this study, we measured the activities of ascorbate peroxidase(APDX), monodehydroascorbate reductase(MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase(GR) subjected to drought or flooding stresses for 4days and following recovery for 3days. Leaves of two soybean lines subjected to drought or flooding showed premature senescence as evidenced by the decrease in water content and total soluble protein content but those of soybean leaves was increased when stresses were recovered for 3days. The activities of APDX and GR subjected to drought or flooding were the decrease but those of enzymes were recovered when water stress was recovered. The activities of MDHAR with drought or flooding were on the decrease, whereas those of DHAR were increased, respectively. Antioxidant contents decreased continually subjected to drought or flooding but it recovered after 3 days subjected to water stresses.

• Korean Journal of Plant Resources
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• v.22 no.5
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• pp.467-472
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• 2009

This study was conducted to break down the self-incompatibility of Astragalus membranaceus Bunge by old-flower pollination, NaCl and $CO_2$ treatment. The old-flower pollination in green house produced fertilization during the 1st and 2nd day after flowering from early September to early October, but almost no fertilization in late August. The most successful pollination occurred in late September at the 1st day after flowering when pod setting was 33.3% and that of seed set was about 86.2%. The old-flower pollination in field showed pod setting for the control group from late August to early October, but no seed set except the days of mid-September and late September. The most successful pollination occurred in late September during the 2nd day of flowering when the percentage of pod setting was 39% and that of seed set was 94.9%. The wrapping in field set pods from late August to early October, but did not set seeds except in mid and end of September. The percentage of pods was 39% and percentage of seeds was 94.9% about flowering after first day in end of September. by field culture. The best result from NaCl treatment was achieved when 1% NaCl treatment in green house produced 21.3% of pod setting in early October and 66.7% of seed set in late September. In field, NaCl 5% treatment produced best result with 7.3% of pod setting and 90.9% of seed set in mid-September. No differences were observed between the $CO_2$ 700ppm treatment and the control group.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.705-709
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• 1997

Changes in retrogradation degree of nonwaxy milled rice cooked at different pressure and stored in electric rice cooker at $74^{\circ}C$ were investigated. The moisture contents of nonwaxy milled rice cooked at $1.0{\sim}1.9\;atm\;and\;1.2{\sim}1.5$ water/rice ratio were $59.9{\sim}64.3%$. When nonwaxy milled rice was cooked at high pressure, X-ray diffraction patterns of cooked rice exhibited the V-type having nearly no crystallinity. Retrogradation peak of cooked rice from DSC thermogram was observed in the temperature range of $41.9{\sim}62.4^{\circ}C$ and was not appeared in cooked rice above 1.5 atm. During storage at cooker for 24 hr, retrogradation enthalpy of cooked rice was increased and retrogradation peak was not appeared above 1.7 atm. In cooking and storage of cooked rice, retrogradation degree measured by ${\alpha}-amylase-iodine$ method in high pressure gelatinized samples was lower than that in low pressure gelatinized ones.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.44-48
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• 1996

Effects of storage temperature on the retrogradation of 50% nonwaxy rice flour gels stored at $20^{\circ}C,\;4^{\circ}C\;and\;-18^{\circ}C$ for 6 days were investigated by ${\alpha}-amylase-iodine$ method, differential scanning calorimetry(DSC) and x-ray diffractometry. The retrogradation of gels increased with increasing storage time and the initial retrogradation rate was higher. The degree of retrogradation gels stored at different temperature increased as following order, $-18^{\circ}C>20^{\circ}C>4^{\circ}C$. The enthalpy of retrograded rice flour by DSC showed similar as the degree of retrogradation by ${\alpha}-amylase-iodine$ method, but the differences between storage temperatures were clear in using ${\alpha}-amylase-iodine$ method. X-ray diffraction patterns of gels stored at $4^{\circ}C\;and\;20^{\circ}C$ showed small peaks at $2{\theta}=17^{\circ}\;and\;20^{\circ}$, but the difference was not detected.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.40-44
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• 2002

We invested effect of the keeping-time of uncured composite and thermal aging, of cured composite on adhesive strength for rubber-brass coated steel cord composite in this study. We also evaluated how the adhesive strength affects to tire endurance. Using PAD adhesion specimen, peel adhesive strength was measured. The uncured composite was kept for several days up to 35 days in factory. Cured composite was also kept for 5 and 10 days at $85^{\circ}C$ in dry oven. Peel adhesive strength was decreased with increasing keeping-time and showed lower value with increasing thermal aging time. The lower peel adhesive strength, the lower tire-endurance. This fact was caused by the humidity and thermal aging which affected in the decrease of adhesive strength of the rubber-steel cord composite and resulted in interface fracture between rubber and steel cord. This phenomenon was confirmed from SEM investigation and tire-endurance. It was just known that corrosion of steel cord's surface and aging of adhesive layer strongly affected to decrease of adhesive strength. This resulted in directly decreasing tire-endurance.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.1-13
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• 2020

The characterization of aging of the pyrotechnic device is conducted thermally, chemically, and spectroscopically. The device is comprised of two parts: (i) igniter composed of Zr and (ii) pyrotechnic delay composed of ZrNi alloy. The thermally induced chemical reaction is identified through Differential Scanning Calorimetry (DSC) and Thermogravimetry Analysis (TGA). The peak deconvolution of the themo-chemical data is used to estimate the enthalpy change of each metallic fuel component. Laser Induced Breakdown Spectroscopy (LIBS) and X-ray Photoelectron Spectroscopy (XPS) are used for chemical species analysis. The decomposition of oxidants by moisture significantly affected the fuel aging, and the formation of oxide film and metal oxide on the fuel surface gave rise to the thermal energy decrease.