• Journal of Ginseng Research
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• v.19 no.3
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• pp.231-236
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• 1995

The antioxidant activity and the pharmacologically active constituents such as nucleosides and phenolic substancs of Panax ginseng C.A. Meyer (white ginseng powder) treated with gamma irradiation (Rl group) and ethylene oxide fumigation (EO group) were compared with those of non-treated ginseng (control group). High performance liquid chromatograms of nucleosides in three groups were similar with each other. The bathochromic effect of phenolic substances at W absorption region tends to be higher for EO group than Rl group. This tendency was also observed in heat treatment of each group. However, the antioxidant activity may have some effects on the labile property of phenolic substances. In summary the gamma-irradiated ginseng was more stable than the ethylene oxide-treated ginseng, but both ginseng samples gave the similar antioxidant activity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1172-1178
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• 2012

In this paper, the gamma ray irradiation test results of the CCD cameras are described. From the low dose-rate (2.11 Gy/h) to the high dose-rate (150 Gy/h) level, which is the same level when the hydrogen explosion was occurred in the 1~3 reactor unit of the Fukushima nuclear power plant, the monitoring performance of the cameras owing to the speckles are evaluated. The numbers of speckles, generated by gamma ray irradiation, in the image of cameras are calculated by image processing technique. And the legibility of the sensor indicator (dosimeter) owing to the numbers of the speckles is presented.

• ETRI Journal
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• v.31 no.5
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• pp.604-606
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• 2009

The primary dose effects on an insulated gate bipolar transistor (IGBT) irradiated with a $^{60}Co$ gamma-ray source are found in both of the components of the threshold shifting due to oxide charge trapping in the MOS and the reduction of current gain in the bipolar transistor. In this letter, the IGBT macro-model incorporating irradiation is implemented, and the electrical characteristics are analyzed by SPICE simulation and experiments. In addition, the collector current characteristics as a function of gate emitter voltage, VGE, are compared with the model considering the radiation damage of different doses under positive biases.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1997.11a
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• pp.155-155
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• 1997

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1252-1256
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• 2004

Radiolytic characteristics of phytic acid by gamma irradiation were investigated, and the antioxidative activity between irradiated phytic acid and commonly used antioxidants including ascorbic acid, tocopherol and butylated hydroxyl anisole (BHA) was evaluated. Phytic acid sodium salt dissolved in a deionized distilled water was irradiated at 0, 5, 10, 15 and 20 kGy. It was found that the level of irradiation had an effects on the degree of degradation. After irradiation, stable DPPH radical scavenging capacity of phytic acid was newly observed, and it was significantly increased by dose-dependent manners (p<0.05). Antioxidant activity of phytic acid in the oil models was higher than that of the other antioxidant during storage, and phytic acid (400 $\mu\textrm{g}$/mL) irradiated at 20 kGy especially showed the highest antioxidative ability among the antioxidants tested during 3 weeks. Results indicated that irradiation induced the radiolysis of phytic acid in an aqueous model system, and the antiradical and antioxidative activities of irradiated phytic acid increased.

• Journal of Nutrition and Health
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• v.37 no.1
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• pp.38-44
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• 2004

Food irradiation has been steadily increased in many countries concomitantly with increasing international trades and concerns about naturally occurring harmful contaminants of food. Although, irradiation provides an excellent safeguard for the consumer by destroying harmful bacteria, it would be necessary to investigate nutritional adequacy of irradiated foods with a special emphasis on such foods as red pepper powders, cold-water fishes (mackerel), sesame seeds that are widely consumed in Korea. These food items are of special concern due to the fact that most of them are imported and that several nutrients contained in them are sensitively reacting to irradiation. We observed changes in the antioxidant nutrients contents, such as vitamin A, $\beta$-carotene, vitamin C and total phenol, and also vitamin B$_1$ in the foods that were irradiated at different dose levels. The nutrients contents in red pepper were respectively 98.6% and 92.3％ for total phenol, and 97.8% and 94.5% for $\beta$-carotene, right after irradiation at the dose of 10 and 20 kGy. The vitamin C contents decreased with irradiation doses up to 76.4% (10 kGy) and 68.5% (20 kGy) and B$_1$ contents decreased to 54.9% and 80.7% of non irradiated red pepper. When the mackerel was irradiated at the applied dose of 3 and 7 kGy, total phenol concentration of the irradiated fish was respectively 91.3% and 94.2% of non irradiated fish. The amounts of vitamin A were 82.6% (3 kGy) and 78.0% (7 kGy) of unirradiated sample and vitamin B$_1$ contents reduced to 30.5% and 51.5%. $\alpha$-Tocopherol content was 33.9% of the non-irradiated one when it was irradiated at 7 kGy. Vitamin A and ${\gamma}$-tocopherol contents in sesame seeds linearly decreased with the applied doses (5 and 10 kGy) Vitamin A contents decreased up to 87.8% (5 kGy) and 82.9% (10 kGy) and that of ${\gamma}$-tocopherol were 72.4% and 66.5% of the unirradiated sample.

• Current Research on Agriculture and Life Sciences
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• v.30 no.1
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• pp.51-59
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• 2012

Fresh oyster mushrooms (Pleurotus ostreatus) were gamma-irradiated at 0, 1, 2, and 3 kGy. The effects on various quality attributes were determined during storage at $5{\pm}1^{\circ}C$. Color changes were more prominent in the cap region than the stem part. At the start of storage increase of Hunter's L-value (lightness) was observed in the caps of 2 and 3 kGy-irradiated samples. The L-value was higher in the all irradiated samples during storage. The trend was different in the case of stem region, where L-value decreased upon irradiation, but remained high throughout storage. The ${\alpha}$-value declined, whereas the b-value increased following irradiation. Irradiation showed a dose-dependent effect on the firmness, which was clearer during storage, but the samples irradiated at 1 kGy maintained an overall better texture than other irradiated samples. The weight loss was also higher in the all irradiated samples during storage. The samples irradiated at 1 kGy showed good physical appearance without any fungal attack at the end of storage; however color change in cap region was quite apparent. The ultra-structural drastic effect of irradiation was understandable using scanning electron microscopy. E-nose analysis demonstrated a clear change in the volatile profiles of all irradiated samples. Although the effect of irradiation on quality characteristics was quite clear but the all irradiated samples were free from fungal attack that was observed in the case of control sample.

• Food Science and Preservation
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• v.5 no.3
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• pp.199-206
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• 1998

Comparative effects of gamma irradiation and methyl bromide (MBr) fumigation on disinfestation and some physicochemical attributes of acorn seeds were investigated. Insects in domestic acorns were identified to be Curculio dentipes Roelofs and Dichocrocis punctiferalis Guenee, which were easily disinfestated immediately after commercial MBr fumigation. Irradiation also showed similar effects on mortality of the insects in different post-irradiation periods; at 3rd day with doses of 1-3 kGy and at around 30th day 0.5-1 kGy. MBr fumigation caused the decrease in lightness (Hunter L value), total phenolics and reducing sugars and the increase in yellowness (Hunter b value) and browning intensity for the subjected samples, as compared with the nontreated control and irradiated ones at 0.5-2 kGy. Furthermore, MBr fumigation resulted in decay for the most part of samples during storage at 5-10 $^{\circ}C$ for 6 months in a PVC box packaging with nets. As a result, optimum levels of irradiation is expected to be roe of the alternatives to chemical fumigants.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.741-745
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• 2002

Effect of gamma irradiation on inhibition of microbial growth and reduction of residual nitrite level in cooked pork sausage were studied during 4 weeks of storage at $4^{\circ}C$. Irradiation at 5 and 10 kGy significantly reduced the number of total aerobic bacteria and almost eliminated coliform bacteria. Irradiation reduced the content of residual nitrite in cooked pork sausage in a dose-dependent manner, and among packaging methods, the sausage with $CO_2$ (100%) packaging was the lowest level of residual nitrite. Results indicate that the irradiation combined with packaging is a useful technology to reduce the residual nitrite in cooked pork sausage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.894-898
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• 2004

This study was carried out to determine the optimum irradiation dose for infant foods with improved energy-density and extend shelf-life using gamma irradiation. Rice and rice porridge were irradiated at 0, 2.5, 5, 7.5, 10, 15 and 20 kGy, and rheological characteristics and total plate count of porridge were evaluated for 6 weeks. Rice and rice porridge at 2.5 kGy dose reduced the viscosity with 22% and 98%, respectively. The result of total aerobic bacteria of non-irradiated rice porridge was 6 log CFU/g and that of 2.5 kGy irradiated rice porridge on 2 weeks storage was 3 log CFU/g, while that of 7.5 kGy irradiated sample was not detected even at the end of storage. Irradiation on rice-based porridge was proper to enhance the total solid in inverse proportion to considering viscosity and extend shelf-life. Gamma irradiation was effective technology in enhancing calorie value of porridge due to reduction of viscosity.