• Journal of Radiation Industry
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• v.4 no.4
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• pp.385-389
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• 2010

In this study, the effect of the concentration of carboxymethylcellulose (CMC) solution on the degradation by irradiation was investigated. The CMC solutions with different concentrations of 3%, 4%, 5%, 6% and 7% were irradiated at the doses of 5, 10, 15, 20, 25 and 30 kGy with gamma ray or electron beam, and the viscosity of CMC solution was measured. The viscosity of the CMC solutions was decreased with an increase in the irradiation dose, but the extent of the degradation by an irradiation was found to be decreased with an increase of the CMC concentration in the solution. The dependency of the irradiation sources showed that an electron beam radiation had degraded the CMC less severely than gamma ray.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.244-244
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• 2006

We developed novel polymer materials composed of thermoresponsive pNIPAAm main chain and photo-resnposive side chains of spirobenzopyran, and analyzed the photoresponsive characteristrics of the aqueous solutions of these copolymers. Further, we prepared various photoresponsive hydrogels composed of the copolymer, and investigated the effect of light irradiation on their properties. As a result, the copolymer exhibited quite unique response to light irradiation and the change in temperature and pH. Especially the drastic photo-induced dehydration was observed in low pH conditions, and photo-induced micro-relief formation was demonstrated using the hydrogel layer composed of the polymer.

• Food Science of Animal Resources
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• v.34 no.4
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• pp.464-471
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• 2014

Ground lean pork was irradiated by an electron beam or X-rays to compare the effects of two types of radiation generated by a linear accelerator on the quality of Bologna sausage as a model meat product. Raw ground lean pork was vacuum packaged at a thickness of 1.5 cm and irradiated at doses of 2, 4, 6, 8, or 10 kGy by an electron beam (2.5 MeV) or X-rays (5 MeV). Solubility of myofibrillar proteins, bacterial counts, and thiobarbituric acid reactive substance (TBARS) values were determined for raw meat samples. Bologna sausage was manufactured using the irradiated lean pork, and total bacterial counts, TBARS values, and quality properties (color differences, cooking yield, texture, and palatability) were determined. Irradiation increased the solubility of myofibrillar proteins in a dose-dependent manner (p<0.05). Bacterial contamination of the raw meat was reduced as the absorbed dose increased, and the reduction was the same for both radiation types. Differences were observed only between irradiated and non-irradiated samples (p<0.05). X-ray irradiation may serve as an alternative to gamma irradiation and electron beam irradiation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.712-716
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• 2011

We investigated changes in the extraction yield and whitening activity of polysaccharides from Undaria pinnatifida sporophyll due to gamma irradiation. U. pinnatifida sporophyll was gamma-irradiated at doses of 10, 30, 50, 70, and 100 kGy, then extracted with hot water and precipitated with ethanol to extract polysaccharides. Crude polysaccharide yields increased with an increase in irradiation dosage, but tyrosinase inhibition activity did not change. Melanin synthesis did not significantly differ between B16BL6 cells treated with irradiated and non-irradiated samples. In conclusion, gamma irradiation increased the crude polysaccharide extraction yield but did not change the whitening activity of U. pinnatifida sporophyll. This implies that gamma irradiation can be used to increase yields in the cosmetic industry, thus increasing profits.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.468-475
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• 2009

This study was conducted to examine the bleaching of an anti-inflammatory agent containing Undaria pinnatifida extract (AIAU). Brown-colored AIAU was irradiated with $^{60}CO$ gamma rays at doses ranging from 10-200 kGy. Discoloring of the anti-inflammatory agent was achieved by gamma irradiation, with significantly removal by 50 kGy irradiation. The main active compound of the agent consisted of 4% U. pinnatifida extract, which inhibited inflammatory symptoms in mouse ear edema by 93%. There was no change in effects against edema, erythema, blood flow and radical scavenging activity by irradiation.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.169-173
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• 2011

This study investigated the effect of gamma irradiation on immune enhancing activity of Chaga mushroom extract (CME). CME was prepared by hot water extraction at $70^{\circ}C$ for 4 hours and lyophilized. Lyophilized CME powder was dissolved with deionized water at $10mg\;ml^{-1}$ and then irradiated at the doses of 10, 30 and 50 kGy by cobalt 60 gamma irradiator. The gamma-irradiated and non-irradiated CME were treated into the splenocyte separated from mouse. Cell proliferation and cytokine production of the immune cells were increased by gamma-irradiated CME and these increases were more prominent when CME was irradiated at higher doses. Therefore, it is considered that gamma irradiation can be an effective method for improvement of the immunomodulating activity Chaga mushroom extract.

• Journal of Radiation Industry
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• v.6 no.3
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• pp.239-244
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• 2012

This study was conducted to investigate bacterial growth, viscosity, color, and sensory properties of gamma-irradiated Tarakjuk powder, a Korean milk porridge powder, at 1, 3, 5, 7, and 10 kGy. The total aerobic bacteria in non-irradiated Tarakjuk powder was $2.56{\log}\;CFU{\cdot}g^{-1}$, whereas it was not observed within the detection limit of $2{\log}\;CFU{\cdot}g^{-1}$ in samples irradiated at more than 1 kGy. Spore-forming bacteria, however, were not observed in all samples within the detection limit of $1{\log}\;CFU{\cdot}g^{-1}$. The viscosity of rehydrated Tarakjuk after gamma irradiation significantly decreased from 16,770 cP to 4,060 cP when irradiated at 10 kGy. The redness ($a^*$ value) and yellowness ($b^*$ value) evaluated using a colorimeter were significantly increased according to the increase in irradiation dose (p<0.05), while there was no difference in color evaluation conducted by panels. The overall acceptance decreased as the irradiation dose increased, and the 5 kGy sample was 4.0 (normal) on a 7-point scale. As a result, it is considered that a gamma irradiation of 5 kGy is enough to sterilize Tarakjuk powder with a acceptable sensory quality.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.53-57
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• 2010

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T. thynnus were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.3
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• pp.293-299
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• 2015

We analyzed the damage effect on Glass Fibre Reinforced Plastics(GFRP) under air flow by irradiation of continuous wave near-IR laser. Damage process and temporal temperature distribution were demonstrated and material characteristics were observed with laser intensity, surface flow speed and angle. Surface temperature on GFRP rapidly increased with laser intensity, and the damaged pattern was different with flow characteristics. In case of no flow, penetration on GFRP by burning and flame generation after laser irradiation was appeared at once. GFRP was penetrated by the heat generated from resin ignition. In case of laser irradiation under flow, a flame generated after burning extinguished at once by flow and penetration pattern on GFRP were differently shown with flow angle. From the results, we presented the damage process and its mechanism.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.381-384
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• 2010

In this study, the microbial safety and mechanical properties of xeno-bone graft material irradiated were investigated during the storage. Xeno-bone graft of the deminerlized bone matrix in carboxy-methyl-cellulose was gamma-irradiated and was cultured in PCA and PDA agar to check microbial contamination. Total aerobic bacteria and fungi were not detected in the irradiated and non-irradiated sample stored in accelerator at $30^{\circ}C$ for 10 months. Viscosity of CMC treated gamma irradiation was also not changed by holding period.