• Journal of the Korean Society of Food Culture
• /
• v.12 no.2
• /
• pp.183-188
• /
• 1997

This study was carried out in order to analyze the changes in general compounds and sugars of traditional Korean soy sauce with varying Meju concentrations (Meju-water ratios of 1 : 4 and 1.3 : 4) and ripening periods (up to 2 years). Along with ripening period, pH decreased and titratable acidity, total acidity and crude protein contents increased, which were higher in 1.3 : 4 than in 1.4. Buffering power increased significantly with increasing ripening period. Crude fat content was higher in 1.3 : 4 than 1 : 4. Moisture content decreased and pure extract content increased significantly with increasing ripening period, which was high in 1.3 : 4. Salt contents increased with increasing ripening period, but decreasd in soy sauce ripened for 2 years. As the result of sugar analysis, reducing sugar showed slow increase with increasing ripening period. Among detected free sugars, galactose was present in the highest concentration and the rest were in the sequence of glucose, fructose. Total free sugar content was highest in soy sauce ripened for 150days in 1 : 4 and 210 days in 1.3 : 4.

• Applied Chemistry for Engineering
• /
• v.8 no.6
• /
• pp.954-959
• /
• 1997

The solid solutions of the $Sr_{1-X}M_XFeO_{3-y}$ (x=0.1, 0.2, 0.3, 0.4, 0.5, M=Ca) system having perovskite structures were prepared in air by heat treatment at 1473 K for 18hr. X-ray diffraction assigns cubic system for all the samples and shows that the lattice volume of each system decreases with increasing x value until x=0.3, but increases abruptly from x=0.4. The mole fractions of $Fe^{4+}$ ion($\tau$ value), the amounts of oxygen vacancy (y value) and finally nonstoichiometric chemical formulas for each composition were determined from Mohr salt analysis. TG/DTA thermal analysis (temperature range: 300~1173K) exhibits that 3-y values of the samples having x=0.1 and 0.2, decrease with temperature and increase almost reversibly with decreasing temperature. The samples of $x{\geq}0.3$, however, didn't show the reversible weight change and the 3-y values of them were nearly 2.5 in cooling process. Conductivities of each sample were varied within the semiconductivity range at relatively low temperature. And the conductivity at constant temperature decreases steadily with x value. The conduction mechanism of this ferrite system may be proposed as a hopping model of conducting electrons between the mixed valence states. At high temperature semiconductivity of each sample changed into metallic property.

• Applied Chemistry for Engineering
• /
• v.18 no.5
• /
• pp.467-474
• /
• 2007

The palladium and gold nanoparticles containing PAN-based active carbon fiber (ACF) with a high specific surface area were prepared. Using the BET, TEM, FE-SEM, and XPS, their specific surface area and pore volume, pore structure, and the change in surface oxygen groups with time were analyzed and $SO_2$ adsorption performances were investigated. Because of the impregnating process, the micropore volume was mostly decreased from 95.5% to 30.5~43.7% compared with the total pore volume. And the change in surface oxygen groups with time was higher for the metal salt than the nanoparticles. Also, $SO_2$ breakthrough time of PAN-ACFs impregnated with Au nanoparticles and metal salts did not change compared with that of the non-impregnated PAN-ACF. But the PAN-ACF impregnated with Pd nanoparticles (100 ppm) showed good $SO_2$ adsorption performance as the breakthrough time of 880 sec. These results indicated that the $SO_2$ adsorption performance depended on the change in surface oxygen groups with time and the moderate impregnation of Pd nanoparticles on the PAN-ACF caused the increase in the $SO_2$ adsorption performance by a catalytic action.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.21 no.2
• /
• pp.109-121
• /
• 2003

Lots of various utilities are buried under the surface. The effective management of underground utilities is becoming the very important subject for the harmonious administration of the city. Ground Penetrating Radar(GPR) survey including other various underground survey methods, is mainly used to detect the position and depth of buried underground utilities. However, GPR is not applicable, under the circumstances of shallow depth and places, where subsurface materials are inhomogeneous and are composed of clay, salt and gravels. The aim of this study is to overcome these limitations of GPR and other underground surveys. High-frequency electromagnetic (HFEM) method is developed for the non-destructive precise deep surveying of underground utilities. The method is applied in the site where current underground surveys are useless to detect the underground big pipes, because of poor geotechlical environment. As a result, HFEM survey was very successful in detecting the buried shallow and deep underground pipes and in obtaining the geotechnical information, although other underground surveys including GPR were not applicable. Therefore this method is a promising new technique in the lots of fields, such as underground surveying and archaeology.

• Korean Journal of Food Science and Technology
• /
• v.43 no.3
• /
• pp.361-368
• /
• 2011

Three types of doenjang were prepared with regular soybean, germinated regular soybean, and a mixture of germinated regular and black soybean. After 90 days of fermentation, pH, moisture, and salt contents of doenjang were $6.01{\pm}0.01-6.72{\pm}0.01$, $53.78{\pm}0.22-57.99{\pm}0.11$, and $14.17{\pm}0.06-15.03{\pm}0.21%$, respectively, showing slight differences according to soybean germination. Amylase and protease activity of doenjang changed similarly during fermentation in all samples. Amino-type nitrogen and free amino acid content of germinated black soybean doenjang after 90 days of fermentation were $1256.21{\pm}1.86$ and 994.46 mg%, respectively, which were higher than those of other samples. A sensory evaluation of germinated regular soybean doenjang showed the highest scores for color, taste, and overall acceptability. These results suggest that high sensory quality doenjang can be prepared using germinated regular soybean and a mixture of germinated regular soybean and black soybean.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.692-697
• /
• 2016

This study examined the effects of salinity and medium used on the induction of sexual reproduction for the mass production of the resting eggs in the marine rotifer Brachionus rotundiformis for 9 days. After exposure to various salinities, the mixis rate in all treatments began to increase on the third day and decreased after the 4th or 5th day. The resting eggs appeared on the 4th day at 10‰, 15‰, 20‰, 25‰. In particular, the fertilization rates with 33.3% and 31.3% at 20‰ and 25‰ on day 6 were higher than those of the others, respectively. Mean mixis rate for 9 day at 0‰ and 20‰ were the highest with 25.3% and 20.2%, respectively, and the fertilization rate (14.0%) at 25‰ was the highest. In the medium experiment used, the mixis rate in all treatments were similar to the results of the salinity experiment. The resting eggs were only found at 0% and 25% of the used medium treatments. While there were no significant differences in the mean fertilization rate of all treatments, the mean mixis rate (22.3%) in the 25% treatment was higher than that of the control (0% treatment). As a result, salt stress was more effective than using the used medium to induce sexual reproduction in B. rotundiformis. The optimal salinity was considered to be 20-25‰, which caused a high mixis and fertilization rate in the rotifer. These results provide basic data for the mass production of rotifer resting eggs.

• Analytical Science and Technology
• /
• v.29 no.5
• /
• pp.234-241
• /
• 2016

The approach presented in this article refers to the bioanalytical method validation for the detection and quantitative determination of arsenic species including arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) in dog plasma by high-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP/MS). The arsenic species were separated using an agilent As speciation column by a mobile phase of 2 mM sodium phosphate monobasic, 0.2 mM ethylenediaminetetraacetic acid disodium salt dehydrate, 10 mM sodium acetate, 3 mM sodium nitrate and 1 % ethyl alcohol at pH 11 (adjusted with 1M NaOH). The method validation experiment was obtained selectivity, linearity, accuracy, precision, matrix effect, recovery, system suitability, dilution integrity and various stabilities. All calibration curves showed good linearity (R²>0.999) within test ranges. The lower limit of quantitation (LLOQ) was 5 ng/mL for As(III), As(V) and DMA, and 20 ng/mL for MMA. The system suitability and dilution values were within 6.5 % and 7.7 %. Subsequently, the developed and validated HPLC-ICP/MS method was also successfully applied to determine the arsenic speciation in dog plasma samples, and the recoveries for the spiked samples were in the range of 91.5–102.2 %. Therefore, this method could be applied to the evaluation of arsenic exposure, health effect assessment and other bio-monitoring studies in biological samples.

• Korean Journal of Food Science and Technology
• /
• v.43 no.6
• /
• pp.735-741
• /
• 2011

Bealmijang is a short-term fermented regional product that is prepared with soybean and extra ingredients. In this study, starter strain candidates were screened from Bealmijang for fermented soybean paste products. Twenty one bacterial strains producing extracellular enzymes (amylase, cellulase, protease, xylanase and lipase) were isolated from Bealmijang, buckwheat sokseongjang. The isolates were assessed for fibrinolytic and antibacterial activities, and salt tolerance. Strain HJ18-4, identified as Bacillus subtilis (AB601598) by biochemical properties (89.6%) and 16S rDNA sequencing (100%), showed the highest enzymatic, fibrinolytic, and antibacterial activities among the isolates. Although the growth of HJ18-4 was inhibited by the increase of NaCl concentration, the growth still exceeded that of B. subtilis KACC 10114 at 5% and 10% NaCl. These results suggest that B. subtilis HJ18-4 is suitable as a starter for soybean paste manufacture.

• Applied Chemistry for Engineering
• /
• v.7 no.6
• /
• pp.1156-1163
• /
• 1996

This study is related to the investigation of the characteristics of quaternary ammonium salt catalyst on the addition reaction of carbon dioxide and glycidyl methacrylate(GMA) to form(2-oxo-1,3-dioxolane-4-yl)methacrylate(DOMA). Among the salts tested, the ones with higher alkyl chain length and with more nucleophilic counter anion showed a higher catalytic activity. Mixed catalysts of NaI and 18-crown-6 showed a good yield of DOMA, but when they are used alone, they showed no catalytic activity. The DOMA monomer was obtained in low polar solvents, while poly(DOMA) could be directly synthesized in aprotic dipolar solvents. Kinetic studies carried out by measuring $CO_2$ pressure in a high pressure batch reactor showed that the reaction rate was first order to the concentration of GMA and $CO_2$ respectively. The rate constant(k) was 0.56L/mol hr and Henry's constant(H') of $CO_2$ in diglyme at $80^{\circ}C$ was $6.5{\times}10^{-4}mol/L{\cdot}kPa$.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.1
• /
• pp.60-64
• /
• 1997

This study attempted to examine the effect on sensory characteristics and texture of Paeksolgi in various volume of adding sugar and steaming time. The most favorite tendency on the quality was over 15% adding sugar and 20 minute steaming time. Evaluation was conducted through objective evaluation firstly and sensory evaluation secondly. The volume of adding sugar was the significant factors which affected the textual characteristics of Paeksolgi. But steaming time and interaction had not affected. In sensory evaluation on the various steaming time Paeksolgi made by steaming time for 20min and over 15% adding sugar showed the most favorite tendency on the overall quality. This condition corresponded to the high level of hardness, adhesiveness, gumminess in comparison with Rheoner measurement. In summary the most favorite factor was 12 hours of soaking time, 10% adding water, 1% of adding salt, over 15% adding sugar, 20 minutes steaming time.