• Macromolecular Research
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• v.11 no.5
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• pp.352-356
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• 2003

The objectives of this study were to investigate the influence of gamma irradiation for sterilization on poly(D,L-lactide-co-glycolide) (PLGA) with different molecular weight and the effect of gamma irradiation on the release behavior of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) from PLGA wafer with various irradiation doses. The effect of gamma irradiation on PLGA was evaluated by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and electron paramagnetic resonance (EPR). The weight average molecular weight (M$_{w}$) and glass transition temperature (T$_{g}$) of PLGA decreased after gamma irradiation. The extent of M$_{w}$ reduction was dependent on irradiation dose and PLGA molecular weight. Using EPR spectroscopy, we successfully detected gamma irradiation induced free radicals in PLGA. The gamma irradiation increased the release rate of BCNU from PLGA wafer at applied irradiation doses except 2.5 Mrad of irradiation dose in this study.study.

• Journal of the Korean Home Economics Association
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• v.30 no.4
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• pp.77-88
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• 1992

To investigate the oxidative stabilities of the ${\gamma}$-ray irradiated soybean during storage and heating and some physico-chemical characteristics of soybean and the extracted soybean oil (SBO) with/without the ${\gamma}$-ray irradiation were determined. The ${\gamma}$-ray level use in irradiation for soybean were 2.5, 5.0 and 10.0 KGY respectively and Acid Value, Peroxide Value, Conjugated Diene Value, Composed Fatty Acids amounts, and Trans Fatty Acid occurrence were determined for all samples, which were incubated at 45$\pm$1$^{\circ}C$ for 25 days heated at 180$\pm$1$^{\circ}C$ for 30 hours. And these values of the ${\gamma}$-ray treated samples were compared to those of nontreated samples. The results were obtained as follows : 1. According to the increased level of the ${\gamma}$-ray irradiation, there was little difference in Dielectric Constant, Viscosity, and the Induction Period by Rancimat. But, in case of 5.0 KGY, oxidative stability was increased more twice than that of non-irradiation. In the quantity of fatty Acids composition of the extracted soybean oil irradiated with 10.0 KGY, palmitic, oleic and linoleic acids were less increased thanb those of non-irradiation, while stearic, linolenic acids were decreased. In the case of 2.5 KGY irradiation, stearic and oleic acids were increased. 2. The Acid Value of SBO according to the ${\gamma}$-ray irradiation level was almost not change, but was 0.1 lower than that of non-irradiation during incubation (45$\pm$1$^{\circ}C$). The Peroxide Value of SBO with the ${\gamma}$-ray irradiation, was very lower than that of non-irradiation, but its effect on oxidative stability was better of SBO treated with 5.0 KGY and 10.0 KGY. In the Fatty Acids composition of SBO, palmitic, stearic, oleic acids were increased, while linoleic, linolenic acids were decreased during incubation(45$\pm$1$^{\circ}C$). This tendency was more obvious due to the ${\gamma}$-ray level. While heating(180$\pm$1$^{\circ}C$), the Acid Value of SBO treated with the ${\gamma}$-ray irradiation was decreased, the Acid Value of SBO irradiated with 2.5 KGY was the lowest. Also the peroxide Values of SBO treated with 5.0 KGY, 10.0 KGY were very lower than that of non-irradiation. Conjugated Diene Value of SBO was almost unchanged according to the ${\gamma}$-level and heating time. 3. When the methyl linoleate was irradiated with the ${\gamma}$-ray, the Trans Fatty Acid was little produced. In case of SBO with non-irradiation, the trans C18:1 was occured about 6.5~7.9%, but trans C18:2 and C18:3 were not shown, while SBO irradiated with the ${\gamma}$-ray 2.5, 5.0, 10.0 KGY, trans C18:3 and C18:2 amount in SBO were increased according to heating time, but trans C18:3 was little occured. As these results, the effects of the ${\gamma}$-ray irradiation to oil containing food were to cut down the energy for food storage and to increase oxdative stability during storge. And also it was shown to be the best that 10.0 KGY of the ${\gamma}$-ray irradiation would be applied to soybean.

• BMB Reports
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• v.35 no.6
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• pp.583-589
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• 2002

The signal transducer and activator of transcription (STAT)1 is a cytoplasmic-transcription factor that is phosphorylated by Janus kinases (Jak) in response to interferon $\gamma$ (IFN-$\gamma$). The phosphorylated STAT1 translocates to the nucleus, where it turns on specific sets of IFN-$\gamma$-inducible genes, such as the interferon regulatory factor (IRF)-1. We show here that gamma irradiation reduces the IFN-$\gamma$ mRNA expression. The inhibition of the STAT1 phosphorylation and the IRF-1 expression by gamma irradiation was also observed. In contrast, the mRNA levels of IL-5 and transcription factor GATA-3 were slightly induced by gamma irradiation when compared to the non-irradiated sample. Furthermore, we detected the inhibition of cell-mediated immunity by gamma irradiation in the allogenic-mixed lymphocytes' reaction (MLR). These results postulate that gamma irradiation induces the polarized-Th2 response and interferes with STAT1 signals, thereby causing the immunosuppression of the Th1 response.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.85-90
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• 2021

The gamma irradiation was on to Poly(butylene sebacate-co-terephthalate) (PBSeT), Poly(butylene adipate-co-terephthalate) (PBAT), Poly(lactic acid) (PLA) and casting polypropylene (CPP) at dose levels from 0 to 50 kGy. The properties of gamma irradiated samples were analyzed using DSC, TGA, UTM and FT-IR spectra. The mechanical and thermal properties of PBSeT and PBAT after gamma irradiation were less affected than CPP. The tensile strength and elongation of PBSeT was not affected by gamma irradiation, while these of PBAT, PLA and CPP were significantly decreased at 50 kGy gamma-ray dose. The thermal stability of PBSeT, PBAT, PLA and CPP showed a similar tendency to tensile strength. The glass transition temperature(T_g) and melting temperature(T_m) of PBSeT and PBAT were not altered by increasing gamma-ray dose, while these of PLA and CPP decreased. The chemical composition of all samples was not modified by gamma irradiation, and it was confirmed by FT-IR spectra. Based on mechanical and thermal stability studies of gamma irradiation on bioplastics, tested biodegradable packaging materials showed a potential to be used in sterilization process up to 35 kGy.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.400-404
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• 2003

This study was to evaluate the effects of gamma irradiation on the germination, nutrient concentrations and growth of spinach and radish. Both the spinach and radish seeds exhibited relatively higher germination rates in response to the low doses of gamma irradiation compared to the non -irradiated control. Leaf DW of the radish did not respond to gamma irradiation but that of the spinach increased significantly in response to a gamma radiation of 4 Gy (P< 0.05). Leaf growth parameters of the spinach including the leaf area and SLA (leaf area/leaf dry weight) also demonstrated increased responses to gamma irradiation. R/S (root dry weight/shoot dry weight), root DW and root length of the spinach exhibited a positive response to gamma irradiation while those of the radish did not. In contrast, SRL (root length/root dry weight) significantly decreased with gamma irradiation at 8 Gy for the spinach, but not for the radish. The tissue nitrogen concentrations of the spinach showed an increased response to gamma irradiation while that of the radish did not. Furthermore, higher concentrations of phosphorus, potassium, calcium and magnesium were found in the irradiated spinach, but not in the irradiated radish. It seems that the non-specific physiological and/or biochemical activities of spinach might be accelerated by gamma irradiation, possibly accounting for the stimulation of nutrient uptake from the root media and early biomass accumulation in the current study.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.732-737
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• 2005

The combinational effect of gamma irradiation and moist heating on the trypsin inhibitor activity (TIA) in soaked and dried soybeans was evaluated by measuring the inhibition using N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) as substrate. Gamma irradiation significantly decreased the TIA level in soybean at doses above 5 kGy, and the $ID_{50}$ (the gamma irradiation dose required to reach 50% inhibition) value for TIA was 13.53 kGy. Soaking prior to gamma irradiation significantly lowered the $ID_{50}$ to 8.44 kGy, and the soaking process enhanced the efficiency to inactivate TIA by as much as 48%. When soaking prior to gamma irradiation was followed by subsequent mild heating ($60^{\circ}C$) process, the $IT_{50}$ (heating time required to reach the 50% inhibition of TIA) value at even 1 kGy (5.28 min) was greatly reduced by over 50% compared to the level for the no-soaking process. In addition, the activation energy of soaking prior to gamma irradiation at 1 kGy was 2.45 kcal/mole, which was also about 50% lower than the 5.10 kcal/mole of dried soybean gamma-irradiated. Based on these results, soaking prior to gamma irradiation is an effective method for TIA inhibition. Furthermore, a combination of two or more processing methods such as soaking, heating and gamma irradiation is much more effective than any single processing method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.334-338
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• 2003

The objective of this study was to demonstrate whether or not the deleterious effects of accelerated aging on seed vigour and viability are alleviated by interaction with gamma irradiation. Seeds of soybean (Glycine max L.) were artificially aged and subsequently irradiated with 4 and 8 Gy of gamma irradiation. Germination rate was negatively affected by accelerated aging and positively by gamma irradiation, with a positive interaction of a 3day-seed aging treatment occurring with 4 Gy, possibly suggesting that 4 Gy of gamma irradiation partially offset the adverse effects of seed aging on germination. However, 5-day aged seeds did not gain any benefits from the gamma irradiation. Electrolyte leakage from the seeds increased with the duration in days aged. Irradiation, however, did not impose any effects on the leakage. Respiration rate of the seed with hypocotyl and primary root was significantly low for the aged seeds, but not for the seeds with both irradiation and aging treatments. Accelerated aging decreased the dry weight of the hypocotyl and primary root of the seeds without any measurable effects of irradiation. $\alpha$-Amylase activity decreased with seed aging and positively responded to gamma irradiation. The data is discussed with regard to the possible roles of gamma irradiation for improving the seed vigour and viability of aged seeds.

• The Plant Pathology Journal
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• v.32 no.2
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• pp.157-161
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• 2016

Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc). Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika.

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.184-187
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• 2002

Blood products from slaughterhouses that are not hygienically prepared for disposal or food consumption pose a human health hazard. Gamma irradiation is an effective method for sterilization of blood products, but may introduce changes in the molecular characteristics of proteins. This study evaluated the effects of irradiation on animal plasma proteins. Bovine and porcine blood was obtained from a slaughterhouse and the plasma proteins purified and lyophilized. The secondary structure and molecular weight distribution of the plasma protein solutions and powders were examined after ${\gamma}$-irradiation at 1, 5, 7 and 10 kGy. Gamma-irradiation affected the molecular properties of the protein solutions, but not the protein powders. Circular dichroism and sodium dodecyl sulfate-polyacrylamide gel electrophoresis studies showed that increased doses of ${\gamma}$-irradiation decrease the ordered structure of plasma proteins in solution, and cause initial fragmentation of the polypeptide chains and subsequent aggregation.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.175-179
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• 1999

To develop a production method for modified starches with less pollution, pH adjustment and gamma irradiation were applied to commerical corn starch. Blue values were significantly decreased , while alkali number, optical transmittance and solubility markedly increased when gamma irradiation was applied to pH 2 adjusted corn starch. Water binding capacity and swelling power at pH 5 were the highest among the samples. Gelatinization viscosity was considerably affected by gamma irradiation and pH of the starch. Gamma irradiation of pH 2 adjusted starch showed the lowest peak viscosity and the best cooling stability among the tested samples . Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability seems feasible by controlling the pH of the starch and gamma irrdiation.