• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.13-19
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• 2015

The effects of electron beam (e-beam) irradiation at up to 10 kGy on the microbiological and physicochemical properties of dried red pepper powders were studied. Samples from Korea, China, and Vietnam were included in this study. In untreated samples, the total number of microbes, such as total aerobic bacteria, yeasts and molds, was in the range of $10^6-10^7CFU/g$. E-beam irradiation at 5 kGy reduced the microbial load by 2-4 log cycles, thus improving the hygienic quality of the samples. Moisture and pH of the samples were unchanged after e-beam irradiation. Reducing sugar content decreased at 1 kGy, followed by a gradual increase at higher radiation doses. At 5 kGy, no significant changes in the content of capsaicinoids were observed between the irradiated and control samples, while a 10 kGy dose led to a significant decrease. The content of pigments did not exhibit apparent changes with increasing dose of irradiation.

• Korean journal of food and cookery science
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• v.32 no.4
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• pp.466-475
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• 2016

Purpose: This study investigated the quality characteristics and antioxidant effects of Yakju added with rose, camellia, or cockscomb flower during fermentation. Methods: The quality characteristics and antioxidant effects were estimated including pH, amino acidity, total acid, ethanol content, color value, sensory test, electric donating ability, nitrite-scavenging ability, and ferrous ion chelating effect. Results: The pH values of Yakjus added with rose, camellia, or cockscomb flower were decreased after 2 days of fermentation and then increased after 4 days of fermentation, with final pH ranging from 4.15 to 4.27. Total acid content and amino acidity were increased during fermentation. The ethanol content in Yakjus fermented with rose, camellia, or cockscomb flower was rapidly increased after 2 days of fermentation, reaching the maximum content of 19.1% after 8 days of fermentation. In color evaluation, the L values of Yakjus added with rose, camellia, or cockscomb flower did not changes during fermentation, whereas values of a and b were increased. Total phenolic compound contents in Yakjus added with rose, camellia, or cockscomb flower were 0.67, 0.59, and 0.52 mg/mL, respectively. Total flavonoid contents in Yakjus added with rose, camellia, or cockscomb flower were 0.20, 0.09, and 0.26 mg/mL, respectively. In sensory test, the overall acceptability of Yakjus added with cockscomb flower was higher than that of Yakju added with rose or camellia flower. However, the difference was not statistically significant (p<0.05). Electron donating ability and nitrite-scavenging abilities were the highest in Yakjus added with rose flower, whereas ferrous ion chelating effect was the highest in Yakjus added with cockscomb flower. Conclusion: These results indicated that Yakjus added with rose, camellia, or cockscomb flower might have valuable functional properties due to their antioxidant effects.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.293-301
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• 2011

The ionospheric delay is the largest error source in GPS positioning after the SA effect has been turned off in May, 2000. In this study, we used 44 permanent GPS stations being operated by National Geographic Information Institute (NGII) to estimate Total Electron Content (TEC) based on pseudorange measurements phase-leveled by a linear combination with carrier phases. The Differential Code Bias (DCB) of GPS satellites and receivers was estimated and applied for an accurate estimation of the TEC. To validate our estimates of DCB, changes of TEC values after DCB application were investigated. As a result, the RMS error went down by about an order of magnitude; from 35~45 to 3~4 TECU. After the DCB correction, ionospheric TEC maps were produced at a spatial resolution of $1^{\circ}{\times}1^{\circ}$. To analyze the effect of the number of sites used for map generation on the accuracy of TEC values, we tried 10, 20, 30, and 44 stations and the RMS error was computed with the Global Ionosphere Map as the truth. While the RMS error was 5.3 TECU when 10 sites are used, the error reduced to 3.9 TECU for the case of 44 stations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.10
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• pp.1565-1570
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• 2014

Response surface methodology (RSM) was used to optimize extraction conditions of Pleurotus cornocopiae. Coefficients of determination (R2) for dependent variables ranged from 0.86 at 0.91. Maximum extraction yield was 40.81% under the following conditions: microwave power of 60.08 watts, ethanolic concentration of 12.33%, and extraction time of 6.86 min. Maximum extraction electron donating ability was 35.72% at 44.13 watts, 19.30%, and 4.21 min. Maximum extraction superoxide dismutase (SOD)-like activity was 34.87% at 114.01 watts, 65.88%, and 1.56 min. Maximum extraction total polyphenol content was 31.77 mg/g at 50.52 watts, 23.00% and 2.90 min. Based on the superimposition of four dimensional RSM with respect to extraction yield, electron donating ability, SOD-like activity, and total polyphenol content obtained under various extraction conditions, the optimum ranges of extraction conditions were as follows: microwave power of 71.48~92.84 watts, ethanol concentration of 55.01~71.66%, and extraction time of 3~9 min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.261-268
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• 2016

This study was conducted to establish roasting conditions for optimization of Citri Unshii Pericarpium antioxidant activity using response surface methodology (RSM). A central composite design was applied to investigate the effects of two independent variables, namely roasting temperature ($40{\sim}100^{\circ}C$; $X_1$) and roasting time ($5{\sim}15min$; $X_2$), on responses such as electron donating ability ($Y_1$), total phenolic content ($Y_2$), total flavonoid content ($Y_3$), and hydroxyl radical scavenging activity ($Y_4$). The maximum electron donating ability was 72.38% at a roasting temperature of $71.12^{\circ}C$ and roasting time of 9.39 min. The maximum total phenolic content was 10.76 mg tannic acid equivalents/g at a roasting temperature of $69.71^{\circ}C$ and roasting time of 8.39 min. The maximum total flavonoid content was 105.99 mg quercetin equivalents/100 g at $72.54^{\circ}C$ and 8.64 min. The maximum hydroxyl radical scavenging activity was 60.33% at $68.97^{\circ}C$ and 9.84 min. Based on the superimposition of three dimensional RSM with respect to electron donating ability, total phenolic content, total flavonoid content, and hydroxyl radical scavenging activity under various conditions, optimum conditions were established as follows: roasting temperature of $70.90^{\circ}C$ and roasting time of 9.03 min.

• Journal of Navigation and Port Research
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• v.35 no.9
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• pp.701-706
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• 2011

Radio waves including GPS signals, various TV communications, and radio broadcasting can be disturbed by a strong solar storm, which may occur due to solar flares and produce an ionospheric delay anomaly in the ionosphere according to the change of total electron content. Electron density irregularities can cause deep signal fading, frequently known as ionospheric scintillation, which can result in the positioning error using GPS signal. This paper proposes a detection algorithm for the ionosphere delay anomaly during a solar storm by using multi-reference stations. Different TEC grid which has irregular electron density was applied above one reference station. Then the ionospheric delay in zenith direction applied different TEC will show comparatively large ionospheric zenith delay due to the electron irregularity. The ionospheric slant delay applied an elevation angle at reference station was analyzed to detect the ionospheric delay anomaly that can result in positioning error. A simulation test was implemented and a proposed detection algorithm using data logged by four reference stations was applied to detect the ionospheric delay anomaly compared to a criterion.

• The Korea Journal of Herbology
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• v.30 no.1
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• pp.11-18
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• 2015

Objectives : The objective of this study is to evaluate antioxidant activity and the main component content change of steaming-drying fermented Gastrodiae rhizoma extract. Methods : The antioxidant activities were determined for total polyphenol, flavonoid contents, SOD-like activity, electron donating activity, nitrite scavenging ability and major functional components(gastrodin and 4-hydroxybenzyl alcohol content) were also measured. Results : The polyphenol content of fermented Gastrodiae rhizoma by S. cerevisiae were higher than those of fermented Gastrodiae rhizoma by A. oryzae, and when the fermentation period is extended. SOD like activity of fermented Gastrodiae rhizoma showed to be increased by fermentation with S. cerevisiae than fermentation by A. oryzae. Electron donating activity of fermented Gastrodiae rhizoma were increased at almost parallel level as vitamin C, by fermentation. Notably, fermentation by A. oryzae was moderately better than fermentation by S. cerevisiae. Flavonoid content of Gastrodiae rhizoma showed to increasing by fermentation, particularly fermentation by S. cerevisiae was proven to be more effective than by A. oryzae. The more steaming-drying or increased period of fermentation would be resulted in more gastrodin contents but under the same conditions, 4-hydroxybenzyl alcohol content of fermentation by A. oryzae in case of steaming and drying 1 time and 3 time was higher than control. Conclusions : These results has strongly hint the possible applicability of fermentation might be effective to improve the diverse biological activities of Gastrodiae rhizoma and may further supports to develop a functional food materials.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.884-888
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• 2007

The aim of this study was to analyze the antioxidant properties of different cultivars of grape skin extract in an in vitro system. The extracts were prepared from eight grape cultivars: 'Campbell Early' (CE), 'Kyoho' (K), 'New Kyoho' (NK), 'Muscat of Alexandria' (MOA), 'Seibel' (S), 'Morgen Schow' (MS), 'Gold Finger' (GF), and 'Meru' (M). The total phenolic acid contents were highest in MS and K. Resveratrol content was high in NK (50.88 mg/l g of coat), and quercetin content was significantly higher in K (0.68 mg/l g of coat) than in the other grape species (0.21-0.44 mg/l g of coat). The K and MS grape species, in which total phenol content was comparatively high (K: $24.15\;{\mu}g/mL$, MS: $25.52\;{\mu}g/mL$), also showed a high level of electron donating activity (K, 53%; MS, 59%). The hydrogen radical scavenging activity of M (50.36%) was significantly higher than the other grape species, including the S (50.21%), MS (49.43%), and K (49.06%) cultivars. Antioxidant activity varied depending on grape species, but overall it was highest in the MS and K cultivars.

• Macromolecular Research
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• v.17 no.8
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• pp.603-608
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• 2009

Novel ultra-high molecular weight polyethylene (UHMWPE)/zirconia composites were previously prepared by the in situ polymerization of ethylene using a Ti-based Ziegler-Natta catalyst supported on to the surface of zirconia, as a bearing material for artificial joints. Tribological tests revealed that a uniform dispersion of zirconia in UHMWPE markedly increased the wear resistance. The effects of zirconia content on the oxidation behavior of the ${\gamma}$-ray-treated UHMWPE/zirconia composite surfaces were examined. The oxidation index that estimates the oxidation degree as the content of total carbonyl compounds was monitored using Fourier transform infrared spectroscopy-attenuated total reflectance. The changes in the surface composition due to the oxidation were confirmed by electron spectroscopy for chemical analysis. The extent of oxidation decreased with increasing zirconia content, which was attributed to the increased crystallinity as well as the decreased polymer portion of the UHMWPE/zirconia composites.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.1056-1062
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• 2008

To evaluate the effect of irradiation on restructured pork jerky containing paprika and Japanese apricot extracts, the quality of protein was determined in vitro based on the formation of trypsin indigestible substrate inhibitor (TIS) and the computed protein efficiency ratio (C-PER) as determined based on the protein digestibility and amino acid analysis. In addition, we compared the effects of electron beam irradiation to those of gamma irradiation. Approximately 3% of the moisture content of pork jerky was reduced in response to irradiation with 3kGy administered using an electron beam however, no additional reduction was observed in samples that were subjected to higher doses of irradiation. In addition, there were no notable differences in the crude protein and fat content of pork jerky samples that were subjected to irradiation, regardless of dose. Furthermore, the total amino acids profiles did not change in response to electron beam irradiation. However, the in vitro protein digestibility increased by 7% in response to 3kGy of electron beam irradiation and 5kGy of gamma irradiation, but no significant changes in digestibility were not observed in response to treatment with higher doses. TIS quantified as trypsin inhibitors were formed in response to irradiation using the electron beam (3kGy) and gamma rays (5kGy), although there was a slight reduction in the production of TIS inhibitors in samples irradiated with higher doses. Moreover, only samples irradiated with 10kGy (electron beam and gamma ray) showed higher TBA values than those of the control samples. Finally, the C-PERs $(2.50{\sim}2.60)$ were greater in all of the irradiated pork jerky samples than in the control samples (2.22). Taken together, these results suggest that electron beam irradiation and the incorporation of extracts (paprika and Japanese apricot) may be useful methods of improving the nutritional quality of pork jerky.