• Preventive Nutrition and Food Science
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• v.8 no.2
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• pp.185-190
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• 2003

Gamma irradiation was used as part of a new processing method to produce a brighter-colored and mild-flavored green tea leaf extract that retained all of its physiological activities. Dried green tea leaf was extracted with 70% ethanol and gamma irradiated at 0,5, 10, 20 kGy. Hunter color $L^{*}$- and $a^{*}$-values were increased with irradiation in a dose-dependent manner, which was a color range from dark brown to bright yellow. However, the irradiation effect gradually disappeared during 3 weeks of storage, with color reverting to that of untreated samples. There was no difference in the radical scavenging and tyrosinase inhibition effect by irradiation. Among antioxidants used, ascorbic acid was the most effective against color reversion. In contrast, cysteine was shown to protect the effect of color change with irradiation. Results indicated that enhanced color of irradiated green tea leaf extract can be effectively controlled by additives such as ascorbic acid and a low storage temperature.e.e.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.725-731
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• 2015

Electron spin resonance (ESR) analysis was conducted for eight different kinds of dried seafood products to investigate their gamma-irradiation status. The specimens consisted of 0~10 kGy-irradiated bones, which included five dried fishes (plaice, hairtail, saury, herring, and dried filefish) and three dried mollusks (beca squid, dried squid, and mitra squid) without flesh or marrow. ESR analysis showed that irradiated specimens exhibited typical asymmetric signals as compared to non-irradiated specimens. ESR signal intensities of all dried fishery samples significantly increased depending on irradiation dose, whereas hydroxyapetite radicals clearly appeared in irradiated plaice, saury, and hairtail. In comparing hydroxyapatite (HA) ratio, irradiated hairtail showed a greater hydroxyapatite-radical generation rate than plaice and saury, and the HA ratio significantly increased with elevated irradiation dose. However, all irradiated plaice and hairtail samples, including 5 and 10 kGy-irradiated saury, showed radiation-derived radicals, whereas filefish and mollusks did not. From the results, ESR spectroscopy was found to have potential to be applied for identifying irradiated plaice, hairtail, and saury, which all contained bones.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1137.2-1245
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• 2001

The ${\gamma}$-irradiated medicinal herbs were examined the genotoxicological safety to consider the possibility of application of the irradiation technology for hygienic purpose. The three medicinal herbs -Glycyrrhigae Radix, Aurantii nobilis Pericarpium and Bupleuri Radix- were irradiated with ${\gamma}$ -rays at the practical dosage of 10 kGy. The hot water extracts of the irradiated herbs were examined in two short-term in vitro tests: (1) Ames test in Salmonella typhimurium TA98 and TA100, (2) Micronucleus test in cultured Chinese hamster ovary(CHO) cells. In the Salmonella reversion assays both with and without metabolic activation, the number of revertant colonies was not increased with each extract from the irradiated herbs, compared with negative controls. No significant difference in formation of the colonies was observed between non-irradiated and 10 kGy-irradiated herbs. These results indicated that no mutagenicity of the irradiated herbs was detected. In the micronucleus tests in cultured CHO cells, the incidences of micronucleus were not increased with irradiated herbs, and no significant difference in the incidences was observed between non-irradiated and irradiated herbs. These results indicated that no cytogenetic toxicity of the irradiated herbs was detected. The results of the two in vitro tests suggest that the irradiated herbs do not show mutagenic effects and cytogenetic toxicity. Further tests of in vivo genotoxicity and chronic toxicity are needed to determine the safety of the herbs irradiated with ${\gamma}$ -rays at practical doses.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.50-57
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• 2011

This study examined the effect of gamma irradiation (3-20 kGy) on the immune activity and physicochemical properties of Myagropsis myagroides (MM) water extracts. MM powder and water extracts were subjected to gamma irradiation at 3, 7, and 20 kGy. The effects of gamma-irradiated MM water extracts on splenocyte proliferation and cytokine IFN-${\gamma}$ and IL-2 secretion were evaluated. The gamma-irradiated MM water extracts resulted in decreased splenocyte proliferation without cytotoxicity. The IFN-${\gamma}$ and IL-2 secretion increased by gamma-irradiated MM water extracts with increasing irradiation dose. For MM powder, the yield and total phenolic compounds (TPC) of water extracts were increased slightly after gamma irradiation. In MM water extracts, the TPC was higher at a dose of 20 kGy, while gamma irradiation decreased the viscosity, pH, and color of the MM extracts. In conclusion, gamma irradiation improved the immunomodulatory activity of MM water extracts, overcoming its potential weakness when applied in the food industry.

• Korean Journal of Environmental Biology
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• v.23 no.4
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• pp.398-404
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• 2005

Radioprotection is of practical importance for the normal tissues of tumor patients subject to radiotherapy, people with planned or accidental exposure to radiation, and the public and radiation workers. Since oxygen enhances radiation - induced biological damage, antioxidants should be related with the function as a radioprotectors. Ascorbic acid or caffeine is an essential component and antioxidant in the diet of humans and a small range of other mammals. The present study investigates functional radioprotection of caffeine and ascorbic acid against gamma radiation in irradiated C57BL/6N mice. Eight-week-old male C57BL/6N mice were irradiated with 6.5 Gy. A caffeine treated group was administered with $80mg\;kg^{-1}$ body weight by intraperitoneal injection, a single treatment 1 hr before irradiation. Ascorbic acid was administered $330\;mg\;L^{-1}$ in drinking water through all the experimental period. According to time schedules, animals were sacrificed by cervical dislocation. And the samples were collected 2 weeks after whole- body gamma irradiation. The caffeine treated group showed lower decrement of body and organ weights than the other experimental groups. The qualitative analysis of circulating testosterone in serum was performed by means of radioimmunoassay (RIA). The normal level of circulating testosterone was maintained by the treatment of caffeine and ascorbic acid. The change of weight of body and organ and the appearance of seminiferous tubules were improved by an effect of caffeine or ascorbic acid against irradiation. Taken together, caffeine and ascorbic acid protects impairment of spermatogenesis against gamma radiation and may act as a radio-protector.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.3
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• pp.302-309
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• 2022

Low-salt fermented pollack Theragra chalcogramma roe (Myungran Jeotgal, MJ), a traditional Korean fermented seafood, was prepared using a commercially available method and irradiated using gamma rays (0-10.0 kGy) to investigate the effect of gamma irradiation (GI) on food quality. After irradiation with 2.5 kGy gamma rays, the number of viable cells in MJ was reduced by one log compared to that observed in non-irradiated MJ, and no living cells were detected after 7.5 kGy GI. Though up to 2.5 kGy GI had no effect on color quality, over 7.5 kGy GI resulted in significantly poor quality MJ surface color. Saturated fatty acid contents increased slightly in irradiated MJ, while those of polyenes and monoenes decreased slightly as the GI dose increased. Exposure of MJ to GI had no effect on the free amino acid and mineral composition. These results demonstrated that the appropriate GI dose for MJ ranged from 2.5 to 5.0 kGy, which may be recommended for industrial application.

• Journal of Photoscience
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• v.9 no.2
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• pp.397-399
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• 2002

The seedling height, leaf width and leaf length of pepper increased in plants grown from seeds irradiated with the low dose of 4 Gy. The $O_2$ evolution in the 4 Gy irradiation group was 1.5 times greater than the control. Pmax was decreased with increasing illumination time by 20% in the control, while hardly decreased in the 4 Gy irradiation group. Fv/Fm was decreased with increasing illumination time by 50% after 4 hours, while Fv/Fm in the 4 Gy irradiation group was decreased by 37% of inhibition, indicating that the low dose $\gamma$ radiation increased resistance of plants to photoinhibition.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.48-55
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• 1994

In this paper, It is studied that the variation of the dielectric absorption of the specimen according to the change with $^{60}$ Co-${\gamma}$ ray irradiation dose of the influence of temperature and applied voltage. In order to investigate the effect of irradiated oriented polypropylene film, we have observed dielectric properties within the temporature range of 30~130 ($^{\circ}C$) and voltage range of 100~250 (V). As for the dependency of temperature by tan $\delta$, the $\alpha$ peak which appears at high temperature increases accordingly to the increment of irradiation dose which is contributed by the crystal region and moves towards the high temperature. The $\beta$ peak which appears the orientation by dipoles and molecular motions in the amorphous region at low temperature. For the dependency of voltage by tan $\delta$ at low temperature, the peak of the tan $\delta$ shifts accordingly to the increment of irradiation dose towards the high temperature region.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.150.2-150.2
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• 2011

Unlike non-ionic clathrate hydrates stably formed by van der Waals interaction between a guest molecule and a surrounding host framework, ionic clathrate hydrates are stabilized by ionic interaction between an ionic guest molecule and the host water-framework. Here, we firstly described the stable entrapment of the superoxide ions in ${\gamma}$-irradiated $Me_4NOH+O_2$ hydrate. Owing to peculiar direct guest-guest ionic interaction, the lattice structure of ${\gamma}$-irradiated $Me_4NOH+O_2$ hydrate shows significant change of lattice contraction behavior even at relatively high temperature(120K). Particularly, we note that ionic-induced dimensional change is much greater than thermal-induced change. Such findings are expected to provide useful information for a better understanding of unrevealed nature of clathrate hydrate fields.

• 전기의세계
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• v.13 no.3
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• pp.13-20
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• 1964

The measurements of X-ray and Gamma-ray Dose Rate have been successfully made by measuring the short circuit current of the Silicon P-N Junction Diode being irradiated. The short circuit current flows when a silicon P-N Junction Diode is irradiated by X-ray of Gammaray radiations due to photovoltaic effect. A brief analysis is given in order to verify the proportionality of a short circuit current to the Dose Rate. Using this method, measurements of X-ray Dose Rate were carried out in the range of 0.05-1600 r/m successfully. The calibration was made by comparing with Victoreen condenser r-meter. Some advantages in this Dose Rate meter over a condenser r-meter were found. One can measure a continous variation of X-ray Dose Rate with this rate meter at the control console of X-ray device.