• Journal of Astronomy and Space Sciences
• /
• v.24 no.4
• /
• pp.269-274
• /
• 2007

We established a regional ionospheric model for investigating ionospheric TEC (Total Electron Contents) variations over the Korean Peninsula during major geomagnetic storms. In order to monitor the ionospheric TEC variations, we used nine permanent GPS reference stations uniformly distributed in South Korea operated by the Korea Astronomy and Space Science Institute (KASI). The cubic spline smoothing (CSS) interpolation method was used to analyze the characteristics of the ionospheric TEC variations. It has been found that variations of TEC over the Korean Peninsula increase when a major geomagnetic storm occurred on November 20, 2003. The TEC has increased about one and a half of those averaged quite days at the specific time during a geomagnetic storm. It has been indicated that the KASI GPS-derived TEC has a correlation with the geomagnetic storm indices (eq. Kp and Dst indices).

• Journal of the Korean Society of Food Culture
• /
• v.21 no.3
• /
• pp.297-302
• /
• 2006

This study has examined the physicochemical properties of the Pleurotus eryngii, including their proximate components, amount mineral content, total dietary fiber, total sugar, reducing sugar and free sugar. Additionally, it measured the P. egii ethanol extracts and the total amounts of polyphenol compounds as well as its electron donating ability (EDA) of the substance fraction (SF). The P. eryngii powder's moisture content was 9.0% and each of the other element content such as carbohydrate, crude protein, crude ash and crude fat was found to be 63.06%, 20.70%, 5.20% and 2.0% respectively. Potassium (K) was shown to be the greatest inorganic content and manganese (Mn) was the lowest. Furthermore fructose, galactose, glucose lactose and maltose free sugar content was found in this order. 387 mg% of the total amounts of polyphenol was found in the P. eryngii whole body ethanol extract, 158 mg% in the stipe extract, 593 mg% in the pileus extract and 607 mg% in the substance fraction (SF). Electron donating ability (EDA) was highest at 91.12% in the whole body extract and lowest at 62.90% in the stipe extract. Additionally, the EDA for substance fraction (SF) 0.02%-0.1% was found to be 57.78-77.33%, which was lower than the 0.02%-tocopherol (93.92%) and BHT (96.72%). From these results, it can be assumed that P. eryngii offers superior antioxidative effects with its high content of fiber, inorganic materials and total amounts of polyphenol as well as high electron donating ability (EDA), thereby making it ideal for use in functional foods and industrial materials.

• Journal of Nutrition and Health
• /
• v.52 no.4
• /
• pp.399-407
• /
• 2019

Purpose: This study was conducted to evaluate the physicochemical properties of different batches of Saururus chinensis using different roasting temperature that were dried at different using different roasting temperatures and their were determined the antioxidative activities of water and 70% ethanol extracts. Methods: Extracts were examined for the total phenolic acid content, the and flavonoids contents and the antioxidant properties, including DPPH radical scavenging activity, ABTs scavenging activity and, the reducing power. Results: Moisture content was significantly higher in the LSC and the crude ash content was significantly higher in the HSC. The crude protein content was higher in the LSC (although not significantly), and the crude fat and carbohydrate contents were higher in the HSC (although not significantly). The total phenolic content was lower in the samples extracted with water, but there was no significant difference. However, the extracts extracted with 70% ethanol at a high drying temperature were significantly higher. The low temperature and high drying temperature batches of Saururus chinensis were significantly higher in the samples extracted with 70% ethanol than those extracted with 70% ethanol. The total phenolic acid content, the total flavonoid content and the electron donating ability were highest in the ethanol extract of Saururuschinensis treated at a high temperature. However, the ABTs radical activity was highest in the water extracted, high-temperature treated Saururuschinensis. The 70% ethanol extract of high temperature roasted Saururuschinensis had the highest antioxidative activities of all the Saururuschinensis batches. Conclusion: The total phenolic acid contents, total flavonoid contents, electron donating activity and reducing power activity were highest in all the 70% ethanol extraction batches of the high-temperature treated samples.

• Food Science and Preservation
• /
• v.18 no.5
• /
• pp.755-763
• /
• 2011

This study was conducted to monitor the quality characteristics Citrus unshiu ethanolic extracts by a response surface methodology. In extraction conditions based on the central composite design with variations in ethanol concentration (0~100%), extraction temperature($35\sim95^{\circ}C$), and ratio of solvent to sample(20 mL/g). The maximum value of yield was 36.31% at $93.18^{\circ}C$, 67.13% of ethanol concentration. The extraction yield and total polyphenol content were improved with the increase of ethanol concentration than extraction temperature. Total flavonoid content was improved with the increase of extraction temperature than ethanol concentration. The coefficients of determinations($R^2$) were 0.8646(p<0.1) and 0.9153(p<0.05) in electron donating ability and hesperidin content, respectively. Estimated conditions for the maximized extraction including yield, total polyphenol content, total flavonoid content, electron donating ability, and hesperidin content were 55~73% in ethanol concentration, $89\sim95^{\circ}C$ in extraction temperature, and 20 mL/g in ratio of solvent to sample.

• Journal of Astronomy and Space Sciences
• /
• v.34 no.1
• /
• pp.7-17
• /
• 2017

In South Korea, there are about 80 Global Positioning System (GPS) monitoring stations providing total electron content (TEC) every 10 min, which can be accessed through Korea Astronomy and Space Science Institute (KASI) for scientific use. We applied the computerized ionospheric tomography (CIT) algorithm to the TEC dataset from this GPS network for monitoring the regional ionosphere over South Korea. The algorithm utilizes multiplicative algebraic reconstruction technique (MART) with an initial condition of the latest International Reference Ionosphere-2016 model (IRI-2016). In order to reduce the number of unknown variables, the vertical profiles of electron density are expressed with a linear combination of empirical orthonormal functions (EOFs) that were derived from the IRI empirical profiles. Although the number of receiver sites is much smaller than that of Japan, the CIT algorithm yielded reasonable structure of the ionosphere over South Korea. We verified the CIT results with NmF2 from ionosondes in Icheon and Jeju and also with GPS TEC at the center of South Korea. In addition, the total time required for CIT calculation was only about 5 min, enabling the exploration of the vertical ionospheric structure in near real time.

• Journal of the East Asian Society of Dietary Life
• /
• v.21 no.5
• /
• pp.713-722
• /
• 2011

This study was conducted to monitor the quality characteristics of Acai (Euterpe oleracea Mart.) ethanolic extracts by a response surface methodology. The independent variables in the extraction experiments were ethanol concentration (0~100%), extraction temperature ($35{\sim}95^{\circ}C$), and ratio of solvent to sample (10~30 mL/g). The coefficients of determinations ($R^2$) were 0.9596 (p<0.01), 0.9356 (p<0.01), and 0.8842 (p<0.05) for total polyphenol, total flavonoid, and electron donating ability, respectively. The electron donating ability and nitrite scavenging effect improved with an increase in ethanol concentration as opposed to extraction temperature. Anthocyanin content with extraction conditions was 74.421~291.841 mg/L and the coefficient of determinations ($R^2$) was 0.9792 (p<0.01). ORAC (oxygen radical absorbance capacity) with extraction conditions was 137.73~562.94 ${\mu}moles$ TE/g and increased with an increase in ethanol concentration and a decrease in the ratio of solvent to sample content. Estimated conditions for maximum extraction including yield, total polyphenol, total flavonoid, electron donating ability, anthocyanin content, and ORAC were 28~58% for ethanol concentration, $60{\sim}68^{\circ}C$ for extraction temperature, and 10~12 mL/g for ratio of solvent to sample.

• Korean Journal of Medicinal Crop Science
• /
• v.12 no.6
• /
• pp.454-458
• /
• 2004

This study was carried out to clarify the effect of sulfur fertilization method on the qualities of safflower (Carthamus tinctorious L.) seed. Sulfur application increased the nitrogen and sulfur content of seed. In nitrogen content, there was no significant difference among sulfur fertilizers, whereas sulfur content was increased by raising ammonium sulfate (AS) amounts by soil application. In application method of AS, there was no significantly difference between foliar application and soil application with 8 kg S/10a. N/S ratio in seed was decreased by sulfur application, and also decreased with the increase of AS amounts by soil application. The contents of lipid and protein were increased by sulfur application. Lipid content was highest in foliar application, and protein content was lowest in AS 4 kg S/10a. By sulfur application, the content of total phenolics and electron donating ability (EDA) were increased by $3.1{\sim}4.7%$ and $3.6{\sim}8.5%$, respectively compared with control. In content of total phenolics, there was no significant difference among sulfur fertilizers, but EDA was higher in sulfur powder 20 kg/10a and AS 8 kg S/10a than that in other fertilizers. Sulfur application showed positive effects on the qualities of safflower seed. In application effects, AS and foliar application were more efficient than sulfur powder and soil application, respectively.

• Korean journal of food and cookery science
• /
• v.30 no.6
• /
• pp.746-756
• /
• 2014

This study investigated the quality characteristics and physiological activities of takju prepared with whole chestnut (15%, 30% and 50% with steamed rice) during fermentation. The pH level began to decrease after the secondary brewing stage. The total acid as well as the organic acid content increased during fermentation. Lactic acid and succinic acid were the main organic acids in takju fermented with whole chestnut. The level of total sugar and reducing sugars in takju fermented with whole chestnut increased at the first brewing stage and then slowly decreased after 4 days of fermentation. Also, the total number of viable cells and microbial populations such as lactic acid bacteria and yeast in the treatments increased to about 108 CFU/mL after 1 days of fermentation and then decreased gradually afterward. The ethanol content in takju fermented with whole chestnut rapidly increased during the initial 4 days of fermentation, to a maximum content of 18.2% after 8 days. The colour values of the treatments did not show any significant differences between 0% and 15% chestnut content. However L value decreased, while the a and b values increased when the whole chestnut content above 30%. The total polyphenol level, electron donating ability, nitrite-scavenging ability and ferrous ion effect also increased as the ratio of whole chestnut increased. Sensory scores of takju fermented with 15% chestnut were greater than those of takju prepared by other treatments.

• Preventive Nutrition and Food Science
• /
• v.13 no.4
• /
• pp.327-333
• /
• 2008

To develop a functional juice using garlic (Allium sativum L.), heated garlic juice was investigated using a central composite design set with variables of treatment temperature (110, 115, 120, 125, and $130^{\circ}C$) and time (1, 2, 3, 4, and 5 hr) using high temperature and pressure treatment apparatuses. Total soluble solid, total acidity, reducing sugar, total pholyphenol contents, electron donating activity (EDA), and ascorbic acid equivalent antioxidant capacity (AEAC) in heated garlic juice were increased with increasing heating temperature and time. The highest total soluble solid content was $17.81\;^{\circ}brix$ at $123.10^{\circ}C$ for 1.10 hr. The highest total acidity was 1.43% at $127.35^{\circ}C$ for 4.35 hr. The highest reducing sugar content was 86.67 mg/mL at $119.90^{\circ}C$ for 4.35 hr. The highest total polyphenol content was 8.42 mg/mL at $127.75^{\circ}C$ for 4.26 hr. The highest EDA and AEAC were 60.09%, and 7.40 mg AA eq/mL at $127.85^{\circ}C$ for 4.23 hr, and $128.10^{\circ}C$ for 4.18 hr, respectively.

• Korean Journal of Food Science and Technology
• /
• v.29 no.1
• /
• pp.38-43
• /
• 1997

Free phenolic acids (FPA), soluble phenolic acid esters (SPA) and insoluble-bound phenolic acids (IPA) were extracted from defatted Perillae semen flour and the antioxidative components in FPA extract was separated by column chromatography and HPLC. Total phenolic content of defatted Perillae semen flour was 0.38% as chlorogenic acid and each percent ratio of the content of FPA, SPA and IPA to total phenolic content was 71.1%, 15.8% and 13.1%, respectively. The antioxidative activity was compared by measuring of electron donating ability (EDA) and thiobarbituric acid value (linoleic acid substrates). The FPA extract was showed the highest antioxidative activity among the three kinds of phenolic extracts. The FPA extract showing the highest antioxidative activity was separated by silica gel column chromatography and then the separated fractions were compared in terms of antioxidative activity. The fractions of acetone : methanol (8 : 2) showing the highest antioxidative activity was further separated by HPLC. Five fractions (F-I, F-II, F-III, F-IV and F-V) were observed on the HPLC chromatogram and F-I fraction showed the highest antioxidative activity.