• BMB Reports
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• v.35 no.6
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• pp.590-594
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• 2002

To elucidate the effect of gamma-irradiation on the molecular properties of myoglobin, the secondary and tertiary structures, as well as the molecular weight size of the protein, were examined after irradiation at various irradiation doses. Gamma-irradiation of myoglobin solutions caused the disruption of the ordered structure of the protein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains. A SDS-PAGE study indicated that irradiation caused initial fragmentation of the proteins and subsequent aggregation, due to cross-linking of the protein molecules. The effect of irradiation on the protein was more significant at lower protein concentrations. Ascorbic acid protected against the degradation and aggregation of proteins by scavenging oxygen radicals that are produced by irradiation. A circular dichroism study showed that an increase of the irradiation decreased the a-helical content of myoglobin with a concurrent increase of the aperiodic structure content. Fluorescence spectroscopy indicated that irradiation increased the emission intensity that was excited at 280 nm.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.222-226
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• 2004

Hydrocarbons induced by gamma-irradiation of green, black, and oolong teas were analyzed to determine whether the hydrocarbons can be used as markers for detecting post-irradiation of these teas. The samples were irradiated at 0, 2.5, 5, 7.5, and 10 kGy. Detection was attempted by extracting fat from the teas, separation of hydrocarbons with florisil column chromatography, and identification of hydrocarbons by gas chromatography-mass spectroscopy (GC-MS). Concentration of hydrocarbons increased with the irradiation dose. The major hydrocarbons in irradiated green, black, and oolong teas were 1-tetradecence (14:1), pentadecane (15:0), 1,7-hexadecadiene (16:2), 1-hexadecene (16:1), 8-heptadecene (17:1), and heptadecane (17:0). Radiation-induced hydrocarbons in teas were 1,7-hexadecadiene and 8-heptadecene. These compounds were not detected in non-irradiated samples, so the hydrocarbons (16:2, 17:1) can be used as markers for detecting post-irradiation of the teas. Furthermore, detection of hydrocarbons after 12 months storage at room temperature remains a suitable method for identifying irradiated teas.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.171-176
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• 2007

Fresh sprouts such as alfalfa, mung bean, radish, broccoli, and soybean sprouts have become very popular due do their high nutritional value. However, there have been several outbreaks of illness in the last few years that have been attributed to sprout consumption. A number of methods have been used to improve the safety of seed sprouts. One promising technology is the use of ionizing radiation treatment. Irradiation with doses up to 8 kGy has been approved in the USA to control microbial pathogens in seeds intended for sprout production. This review focuses on the potential use of ionizing radiation in reducing the pathogen levels in seed sprouts. The effects of irradiation on seed germination and the nutritional quality of the sprouts are discussed.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.323-326
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• 2002

Ionizing radiation can be used to sanitize herbs contaminated by various microorganisms. However, health concerns related to irradiation damage to complex molecules in plants necessitate that methods be developed to monitor such damage. To elucidate DNA damage of herbs caused by irradiation, the DNA comet assay was used for Astragalus membranaceus Bunge and Havenia dulcis Thumb, irradiated at 1, 5, 7, and 10 kGy. With increasing irradiation doses, the tails of comets became longer with average tail length increasing from 17 (non-irradiated) to 124 (10 kGy) $\mu$m in Astragalus membranaceus Bunge. Above 7 kGy, some of the tails were separated from the heads of comets. Distribution patterns of the tail length of In comets selected randomly in the irradiated herbs were analyzed to quantify the DNA damage. These results clearly suggest that the DNA comet assay is an effective and inexpensive tool for the detection of irradiation damage to DNA in herbs.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.176-179
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• 2006

Electron beam irradiation was applied to examine the microbial growth and qualities of vacuum-packaged Astragalus membranaceus, a Korean medicinal herb. Samples were irradiated at dose of 2, 4, 8, 12, and 16 kGy, respectively. Microbiological data on A. membranaceus showed that populations of total bacteria, yeast and mold, total coliforms were significantly reduced with increase of irradiation dose. Populations of microorganisms in A. membranaceus were decreased by 2-3 log cycles at 8 kGy irradiation. Color measurements showed that electron beam treatment caused negligible changes in Hunter color L, a, and b values of A. membranaceus. Sensory evaluations showed that there were no significant changes among the samples. These results suggest that electron beam irradiated A. membranaceus have better microbial safety and qualities, compared with the non-irradiated control.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.89-92
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• 2003

The effect of gamma-irradiation on microbiological growth in kale juice during storage was studied. Fresh kale juice was prepared and irradiated at 0, 1, 3, 5, 7, 10, and 15 kGy. D values for total bacteria, yeast and mold, Salmonella, E. coli, and Pseudomonas were 3.6, 4.0, 3.2, 1.4, and 1.6 kGy, respectively. E. coli and Pseudomonas were eliminated completely at 5 and 7 kGy, respectively. Gamma-irradiation also reduced total viable bacteria during storage. Therefore, these results indicate gamma-irradiation can prevent microbial spoilage of fresh kale juice by inactivating pathogenic microorganisms.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.294-300
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• 1986

Ethylene oxide (E.O) fumigation and gamma irradiation were applied to comparative researches on the sterilizing effect and physicochemical quality of sound red and black peppers. The microorganisms contaminated in the sample, including total bacteria, aerobic spores, acid tolerant bacteria, fungi, osmophilic molds and coliforms were sterilized with irradiation doses of 7 10 kGy, while E.O fumigation in a commonly used condition proved insufficient for the destruction of them. Both treatments affected more or less chemical components of the sample, such as pungent principle, pigment, essential oils and volatile flavors, but the gamma irradiation at the doses for radurization and radicidation was shown to be safer than E.O fumigation.

• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.129-138
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• 2004

The changes in DNA damage were investigated during storage after irradiation. Beef, pork and chicken were irradiated at 1.0, 3.0 and 5.0 kGy and stored for 6 months at $-20^{\circ}C$. The comet assay was applied to the sample muscles at the beginning of irradiation and at the end of storage. Muscles were isolated, sliced, and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 2 min. and then stained. DNA fragmentation in tissues caused by irradiation was quantified as tail length and tail moment (tail length ${\times}$ % DNA in tail) by comet image analyzing system. Right after irradiation, the differences in tail length between unirradiated and irradiated muscles were significant(p<0.05) in beef, pork and chicken. With increasing the increasing doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. Similarly even 6 months after irradiation, all the irradiated muscles significantly showed longer tail length than the unirradiated controls. The results represented as tail moment showed similar tendency to those of tail length, but the latter parameter was more sensitive than the former. These results indicate that the comet assay could be one of the simple methods of detecting irradiated muscles. Moreover, this method suggest that using comet assay, we were able to detect DNA damage differences even after 6 months after irradiation.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1112-1117
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• 2010

This study was conducted to evaluate and compare the quality changes of commercial sliced and pizza cheeses processed by gamma and electron beam irradiation. The $L^*$-value of sliced and pizza cheeses decreased and the $a^*$-value decreased only in pizza cheese by both irradiation sources. There was no change in pH. There was no difference in 2-thiobarbituric acid reactive substances (TBARS) value between non-irradiated and irradiated samples at a dose of 3 kGy or less (p<0.05). However, both irradiation sources resulted in increased TBARS value in sliced and pizza cheeses at 5 kGy. Sensory evaluation revealed that irradiation influenced odor, taste and overall acceptability of both cheeses and may cause the limitation of consumers' acceptance for irradiated cheese products. Results indicate that both gamma and electron beam irradiations with less than 3 kGy may not influence significantly the physicochemical quality of sliced and pizza cheeses. However, to meet a market requirement, a method to overcome the sensory deterioration of cheeses should be developed and applied.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.151-161
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• 1994

Gamma irradiation was applied to red ginseng for improving its quality. Irradiation at 5~7 kGy was effective for sterilizing all contaminated microorganisms of red ginseng. At the dose levels, no significant shanges in physicochemical properties (color, saponin, lipid rancidity and fatty acids etc.) were observed even after 6 months storage. Gamma irradiation was also effective for the improving hygienic quality of packed red ginseng with high moisture content (up to 20%), without any quality deterioration.