• Food Science and Preservation
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• v.18 no.3
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• pp.319-327
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• 2011

This study was conducted to monitor the quality characteristics of mate (Ilex paraguarensis) ethanolic extracts via the response surface methodology. In the extraction conditions that were based on the central composite design with variations in the ethanol concentration (0-100%), extraction temperature($35-95^{\circ}C$), and the ratio of the solvent to the sample (10~30 mL/g). The extraction yield and total polyphenol content improved with the increase in the ethanol concentration than in the extraction temperature. The caffeic acid content increased with the decrease in the solvent ratio. The coefficients of determinations ($R^2$) were 0.8842 (p<0.05), 0.8729 (p<0.05), and 0.9205 (p<0.05) in terms of the electron donating ability, nitrite scavenging effect (pH 3.0), and SOD-like ability, respectively. The estimated conditions for the maximized extraction, including in terms of the yield, total polyphenol content, caffeic acid content, and electron donating ability, were a 21-48% ethanol concentration, a $76.4^{\circ}C$ extraction temperature, and 10-14mL/g solvent-to-sample ratio.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.984-989
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• 1999

This study was carried out to investigate the effects of ethanol extracts on lipid oxidation of oil emulsion. The results are as follows; The scavenging ability of plant extracts for hydroxyl radical was found, and plant extracts played an important role as a strong chelating agents to bind iron if Fe2+ ion exists in oil emulsion. Pinus densiflora(PD), Lithospermum erythrorhizon(LE) and PD＋LE acted as strong chelating agents to bind iron to reduce lipid oxidation in oil emulsion. The content of Fe2+ ion in ethanol extracts from LE and PD＋LE were significantly higher(p<0.05) than that of ethanol extracts from PD. The content of total iron has same tendency. The ascorbic acid content of PD(16.36ppm) was slightly higher than those of LE(13.08ppm). Electron donating ability of PD was significantly higher(p<0.05) than those of LE. However, the superoxide(SOD) like ability of LE showed a little higher than those of LE and PD＋LE, which means the strong antioxidant activity of LE. The nitrite scavenging effects were dependent on pH value, however, they decreased as pH value increased. Especially, they almost didn't show the nitrite scavenging effect in pH 6.0. In conclusion, the PD and LE extracts may be used as natural antioxidant sources to reduce lipid oxidation in oil emulsion.

• Corrosion Science and Technology
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• v.20 no.4
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• pp.196-203
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• 2021

To improve corrosion resistance and reduce the hydrogen uptake of 22MnB5, up to 5% Mg was added to the AlSi coating of 22MnB5. After hot-stamping and electrocoating were done on the metallic-coated specimen, the surface characteristics of the steel, hydrogen uptake content, and corrosion resistance were examined by transmittance electron microscopy, thermal desorption spectrometry, cyclic corrosion testing, and electrochemical impedance spectroscopy. Mg was investigated as MgO on the surface layer after hot-stamping while it existed as Mg₂Si before hot-stamping. The total hydrogen content of 22MnB5 was decreased along with the Mg content. However, there was no difference at 0.2 wt% or more. When a small amount of Mg was added, the coating corrosion resistance was decreased, but when it was added at around 1.0 wt%, the greatest corrosion resistance increase was seen. However, when 3 wt% or more was added excessively, the corrosion resistance was decreased. MgO on the surface was considered to suppress H uptake by the AlSi melting solution and increase the barrier effect of the coating.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.260-265
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• 2007

This study was carried out to investigate the effect of Electron Beam irradiation on physico-chemical characteristics of Hanwoo meat. A total of sir beef carcasses $(280{\sim}300\;kg)$ that were quality grade $1^+$(marbling score No. 7, meat color No. 4, maturity No. 1, texture No. 1) was purchased at the commercial slaughter house. The carcasses were transported and washed using high pressure water, and pasteurized with 50% ethyl alcohol in the laboratory. After the carcasses were deboned and trimmed, loin and round were taken out to make steak (1.5 cm thickness) or patty respectively. Samples were wrap or vacuum packaged and irradiated with 0, 3, 4.5, 6 and 7.5 kGy using electron-beam accelerator. Irradiated samples were used to measure pH, moisture, crude protein, crude fat, and meat color. There was no significant (p>0.05) difference in pH between vacuum packaged (VP) and wrap packaged (WP) treatment, and the pH was not changed by electron-beam irradiation levels. Both control and irradiated treatments of steak showed higher tendency in moisture content. In crude protein content, control was higher than irradiated treatment in steak, but there were no difference in patty. Lightness ($L^{\ast}$) of meat color has no difference between irradiated and non-irradiated treatment (p>0.05). The value of redness and Yellowness of meat was dropped by increasing irradiation (p<0.05), but there was no difference between control and 3 kGy treatment (p<0.05).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.209-214
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• 2006

One hundred Individuals that were collected from plains and mountains all around South Korea were used for this experiment. The inhibition abilities of lipid peroxidation by Artemisia spp. collections were compared with BHT (butylated hydroxytoluene). The results could be confirmed the excellency fur control of lipid peroxide level such as BHT 200 ppm in all mugwort collections. Antioxidant activity (AEAC), electron donating ability (EDA), total phenolic compound, and flavonoids of 100 Artemisia spp. collections were analyzed. Total phenolic compound contents of Artemisia spp. collections were ranged from 156 to 1,767 rng/100 g, and mugwort collections with more than 900 mg/100 g of total phenolic compound content were 20 individuals. Electron donating abilities were ranged from 13.4 to 95.0%, and mugwort collections over 90% of electron donating ability were 23 individuals. Antioxidant activity of ethanol extracts that used ABTS and DPPH radical were measured and mugwort collections with high total phenolic compound contents had high radical exclusion ability as well. Artemisia spp. collections, AC-60, AC-67, AC-77, that showed the high levels of antioxidant activities and had good growth characters and productivity, were selected for mass production.

• Food Science and Preservation
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• v.16 no.3
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• pp.427-434
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• 2009

We collected glasswort (Salicornia herbacea L.) from the Jollanam-do area (Hwangsan-myeon in Haenam, Jeungdo-myeon in Sinan, and Yeomsan-myeon in Yeonggwang) from June to October 2007, and analyzed levels of total amino acids, free amino acids, and total polyphenolic compounds and electron donating ability and SOD-like activity. The total amino acid content was $3,338.75{\sim}4,491.63\;mg$/100 g in the sample from Haenam, $3,086.48{\sim}3,782.89\;mg$/100 g in the sample from Sinan, and $3,134.3{\sim}4,364.17\;mg$/100 g in the sample from Yeonggwang. Proline was the main free amino acid from June through to September, and the level increased during June, the early period of maturation, and then decreased with further ripening. The total content of free amino acids was $472.75{\sim}1,080.98\;mg$/100 g in the sample from Haenam, $440.46{\sim}621.77\;mg$/100 g in the sample from Sinan, and $387.64{\sim}669.28\;mg$/100 g in the sample from Yeonggwan. Total polyphenolic compound level was $11.1{\sim}15.61\;mg/g$ in the sample from Haenam, $12.71{\sim}21.03\;mg/g$ in the sample from Sinan, and $13.13{\sim}22.28\;mg/g$ in the sample from Yeonggwang. Electron donating ability was 53.8.70.9% in the sample from Haenam, $62.7{\sim}88.8%$ in the sample from Sinan, and $63.0{\sim}72.7%$ in the sample from Yeonggwang. SOD-like activity was $28.7{\sim}41.0%$ in the sample from Haenam, 28.5{\sim}36.5% in the sample from Sinan, and 23.5.39.6% in the sample from Yeonggwang.

• Food Science and Preservation
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• v.16 no.6
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• pp.908-914
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• 2009

A central composite design was used to optimize extraction of propolis materials using ethanol. The independent variables in extraction experiments were ethanol concentration (50, 60, 70, 80, 90%, v/v) and extraction time (1, 2, 3, 4, and 5 h). Higher ethanol concentration and shorter extraction time increased total polyphenol content, but total polyphenol concentration began to decrease when ethanol concentration was higher than 80% (v/v). Ethanol concentration was more important than extraction time in optimization of total polyphenol content in propolis extracts. Electron-donating ability increased with ethanol concentration and shorter extraction time, with ethanol concentration being of greater significance. Antioxidant ability in extracts was optimal at an ethanol concentration of 65 - 75% and with an extraction time of 2.2 - 3.6 h. Nitrite-scavenging ability was increased with use of higher ethanol concentration and shorter extraction time. Total flavonoid content was maximized with an ethanol concentration of 68 - 82% and an extraction time of 2.4 - 3.7 h. Total flavonoid content was affected by both ethanol concentration and extraction time. By superimposition of contour plots, an ethanol concentration of 72 - 82% and an extraction time of 2.2 - 3.3 h were optimal for preparation of propolis extracts.

• Journal of Astronomy and Space Sciences
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• v.33 no.4
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• pp.287-293
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• 2016

The equatorial region of the Earth's ionosphere exhibits large temporal variations in electron density that have significant implications on satellite signal transmissions. In this paper, the first observation results of the variations in the trough of the equatorial ionospheric anomaly at the permanent Global Navigation Satellite System (GNSS) site in Chuuk (Geographic: $7.5^{\circ}N$, $151.9^{\circ}E$; Geomagnetic: $0.4^{\circ}N$) are presented. It was found that the daytime Global Positioning System (GPS) total electron content (TEC) values vary according to the 27 day period of solar rotation, and that these trends show sharp contrast with those of summer. The amplitudes of the semi-annual anomaly were 12.4 TECU (33 %) on $19^{th}$ of March and 8.8 TECU (23 %) on $25^{th}$ of October respectively, with a yearly averaged value of 38.0 TECU. The equinoctial asymmetry at the March equinox was higher than that at the October equinox rather than the November equinox. Daily mean TEC values were higher in December than in June, which could be interpreted as annual or winter anomalies. The nighttime GPS TEC enhancements during 20:00-24:00 LT also exhibited the semi-annual variation. The pre-midnight TEC enhancement could be explained with the slow loss process of electron density that is largely produced during the daytime of equinox. However, the significant peaks around 22:00-23:00 LT at the spring equinox require other mechanisms other than the slow loss process of the electron density.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.271-276
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• 2000

Electron beam (EB) irradiation was compared with gamma ray (GR) in terms of their effects on physicochemical qualities of microbial-decontaminated red pepper powder. The pH and soluble solid of the samples were relatively constant when exposed to EB and GR up to 15 kGy, which also did not induce significant chances in total and reducing sugars. The water soluble pigment and capsanthin content of red pepper powder showed a decreasing tendency as the irradiation dose increased. However, the pungent components, capsaicin and dihydrocapsaicin were shown resistant to irradiation doses applied. Based upon the results, EB was similar to GR in its effect on the physicochemical attributes of the samples, and the irradiation doses required for microbial control were not detrimental to the quality attributes of red pepper powder.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1231-1237
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• 2008

This study was conducted to investigate the functional biological effects of hot water and ethanol extracts from Taraxacum mongolicum (TM). Then, the hot water and ethanol extracts of TM were measured for total flavonoids content, total phenolics content, electron donating ability, nitrite-scavenging ability, SOD-like activity, tyrosinase inhibitory effect, and elastase inhibitory effect. Total flavonoids contents of hot water and ethanol extracts from TM were 7.80$\pm$0.97 mg/g and 9.12$\pm$0.51 mg/g, respectively, and total phenolics contents were estimated as 54.20$\pm$1.95 mg/g for water extract and 79.43$\pm$4.44 mg/g for ethanol extract. The $RC_{50}$ values for electron donating ability of hot water and ethanol extracts were 943.98 $\mu$g/mL and 309.41 $\mu$g/mL. SOD-like activity and nitrite-scavenging ability were dependent on concentration of hot water and ethanol extracts, and the activity of ethanol extract was higher than that of hot water extract. However, hot water and ethanol extracts from TM showed no inhibitory activities on the elastase and tyrosinase inhibitory activities. Based on the above results, the ethanol extract of TM seems to be the most pertinent for use as functional food and cosmetic.