• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.84-89
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• 1972

An experiment was carried out to investigate the optimum doses of gamma-irradiation for sprouting inhibition of onion bulbs with irradiation time and storage conditions. The results. obtained are as follows: 1) The irradiation doses of 5, 7 and 10 krad, respectively, at 11, 32 and 66 days after harvest were sufficient to inhibit subsequent sprout of onion bulbs obtained from Nampyeong district. When they were irradiated at 96 day after harvest, however, there was little sprout-inhibition by 15 krad. In case of onion bulbs obtained from Changnyeong district, sprout was inhibited by doses of 8 and 12 krad respectively, at 51 and 89 days after harvest. 2) Low-temperature storage after irradiation was not effective in sprout-inhibition of onion bulbs. Onion bulbs stored at low temperature of $5^{\circ}C$ rather showed higher sprouting rate as compared with that of room temperature. 3) Rot increased in irradiated lot and at room temperature, and spores of Aspergillus sp. were little germinated at a level of 100 krad. 4) The respiratory rate of irradiated onion bulbs was higher immediately after irradiation but lower one week after irradiation than control. Respiratory quotient of tissues seems to be little affected by gamma-irradiation.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.808-815
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• 2022

In this study, gamma-irradiated mackerel (Scomber japonicus) meat was stored in a refrigerator for 20 days to examine the physicochemical changes related to fishy smell. The effect of gamma irradiation on the inhibition of the activity of crude urease extracted from Vibrio parahaemolyticus was also evaluated. Increased levels of trimethylamine (TMA) and volatile basic nitrogen (VBN) content, which are the main components causing fishy smell, were significantly reduced by day 20 of storage after gamma irradiation, indicating that freshness was maintained during storage. The ammonia nitrogen contents of 3, 7, 10, and 20 kGy gamma-irradiated groups were significantly decreased by 6.5, 15.2, 17.4, and 23.9%, respectively, compared to non-irradiated groups on day 20 of storage. In addition, urease activity decreased in a gamma irradiation intensity-dependent manner. Volatile organic compounds (VOCs) were measured during the storage of gamma-irradiated mackerel meat. The contents of ethanol, 2-butanone, 3-methylbutanal, and trans-2-pentenal, which are known to cause off-flavors due to spoilage of fish, were significantly reduced by day 20 of storage. Therefore, gamma irradiation can be considered useful for inhibiting urease activity and reducing fishy smell during fish storage.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.228-233
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• 2009

This study was conducted to examine the changes in the molecular structure and physiological activities of silk fibroin by gamma irradiation. The results of gel permeation chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the molecular weight of fibroin was increased depending upon the irradiation dose. Secondary structure of fibroin determined by using circular dichroism revealed that the ratio of $\alpha$-helix was increased up to 10 kGy and then decreased depending upon the irradiation dose. Whereas, the ratio of $\beta$-sheet, $\beta$-turn, and random coil were decreased and then increased with an alteration in the $\alpha$-helix secondary conformation. The 2.2-diphenyl-1-picryl-hydrazil (DPPH) radical scavenging activity of fibroin was increased by gamma irradiation at 5 kGy, but was decreased above 10 kGy depending upon the irradiation dose. Also, the inhibition activities of tyrosinase and melanin synthesis of fibroin were increased by gamma irradiation. These results indicated that gamma irradiation could be used as an efficient method to make fibroin more suitable for the development of functional foods and cosmetics.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.764-770
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• 1997

For the purpose of improving hygienic quality of dried-spirullina and dried-sea tangle powders as raw materials of health food, the comparative effects of ozone treatment and gamma irradiation on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, coliforms and molds below detective levels $(<10^{1}\;CFU/g\;sample)$, while ozone treatment for 8 hr up to 18 ppm could not sufficiently eliminate the microorganisms of the samples. Physicochemical properties including compositions of fatty acid and amino acid, minerals, pH and natural pigments were not changed by gamma irradaition up to 10 kGy, whereas, ozone treatment caused changes in pH, TBA value, natural pigments and fatty acid compositions. Especially, ozone treatment markedly decreased unsaturated fatty acid of the samples.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.138-141
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• 2007

The aim of this study was to investigate the effect of irradiation treatment on the inactivation of pathogens in ready-to-use cooked carrot. The pathogens tested were Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, and Listeria inocua. Following the inoculation of these organisms into cooked carrot (about $10^6-10^8\;CFU/g$), the growth of each was inhibited due to irradiation for 24 hr of storage at $20^{\circ}C$. S. typhimurium and E. coli inoculated into cooked carrot were not detected following irradiation with 3 kGy. S. aureus and L. inocua inoculated into the cooked carrot decreased by 5 logs (CFU/g) following 2 kGy irradiation. The range of $D_{10}$ values was from 0.30-0.50. The Hunter color, $L^*-,\;a^*-$, and $b^*-values$, and the hardness of the cooked carrot were not effected by irradiation treatment. The sensory score of irradiated cooked carrot was not statistically different from that of non-irradiated samples (p>0.05). These results indicate that low dose irradiation can enhance the microbial safety and extend the shelf-life of ready-to-eat foods such as cooked carrot.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.390-395
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• 2009

Red radish seeds were irradiated at doses up to 8 kGy using electron beam (e-beam) and gamma ray ($\gamma$-ray). The seed viability and functional properties (carotenoid, chlorophyll, ascorbic acid, and total phenol) of sprouts grown from these irradiated seeds were evaluated. High germination percentage ($\geq$97%) was observed in seeds irradiated at $\leq$5 kGy, but the yield ratio and sprout length significantly decreased with increased irradiation dose. Irradiation at $\geq$6 kGy resulted in curling of the sprout roots. Sprouting enhanced the functional properties of red radish seeds as indicated by the increased carotenoid, chlorophyll, ascorbic acid, and total phenol contents during germination. However, radiation treatment hampered the growth of seeds resulting in underdeveloped sprouts with decreased carotenoid, chlorophyll, ascorbic acid, and total phenol contents. In general, e-beam and $\gamma$-ray irradiation of red radish seeds showed similar effects on the seed viability and functional properties of sprouts. Postharvest storage reduced the functional quality of sprouts.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.137-142
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• 2005

The genotoxicological safety of fermented vegetables pasteurized by gamma irradiation was examined to consider the possibility of the application of irradiation for extending of fermented vegetables. A fermented vegetable was irradiated at 20 kGy to assure its toxicological safety even at a high dose of radiation. The Ames test with Salmonella typhimurium (TA98, TA100, TA1535, TA1537) and Escherchia coli (WP2), and the chromosomal aberration test in Chinese hamster lung (CHL) cells were performed. In vivo micronucleus test were conducted in mouse bone marrow cells. With or without metabolic activation, negative results were obtained in the Ames test and the chromosomal aberration test. In the micronucleus test, there was no enhancement in the formation of micronucleus, and there were no such significant differences between the irradiated and non-irradiated samples. The observed results indicated that, a level of 20 kGy of gamma irradiation on the fermented vegetable did not bring about any genotoxic effects under the described experimental conditions.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.341-346
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• 2006

This study was performed to examine the effects of ${\gamma}$-irradiation on the volatile flavor compounds of dried leeks (Alliums tuberosum R.). Volatile compounds of dried leeks were extracted using simultaneous steam distillation and extraction (SDE), and analyzed by gas chromatography/mass spectrometry (GC/MS). Forty-one, 51, 45, and 42 compounds were tentatively identified in control, 1, 3, and 10 kGy irradiated samples, respectively. The constituents of flavor compounds in irradiated dried leeks were similar to non-irradiated samples. However, the intensities of the peaks were clearly different between them. Sulfur-containing compounds were detected as dominant compounds in all samples and their amounts decreased after ${\gamma}$-irradiation. ${\gamma}$-Irradiation reduced the total concentration of volatile compounds from leeks by 23.19, 15.09, and 30.23% at 1, 3, and 10 kGy doses, respectively.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.232-235
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• 2004

Since ready-to-use (RTU) products are not fully cooked, the shelf-life of the product is comparably short and the products are easily spoiled when contaminated with food-borne pathogens. Low-dose gamma irradiation of 0.5, 1, or 2 kGy effectively reduced the total aerobic bacterial counts in 2 Korean manufactured RTU products by 1.63 to 2.95 log CFU/g during cold storage. Irradiation at 2 kGy reduced the psychrotrophic bacterial counts in most of the samples to below the limit of detection (< log CFU/g). Irradiation at 0.5 kGy completely eliminated Escherichia coli from the commercial RTU samples.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1305-1309
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• 2009

This study evaluated the effects of $\gamma$-irradiation on immunomodulating properties and structural changes of ${\beta}$-glucan. ${\beta}$-Glucan solutions (10 mg/mL) were ${\gamma}$-irradiated at 10, 30, and 50 kGy. Splenocyte proliferation and cytokine (interferon-${\gamma}$ and interlukin-2) productions by ${\gamma}$-irradiated ${\beta}$-glucan were evaluated in in vivo and in vitro, and structural changes of ${\beta}$-glucan were also determined after ${\gamma}$-irradiation. ${\gamma}$-Irradiation on ${\beta}$-glucan at 50 kGy enhanced splenocyte proliferation and cytokine productions, (p<0.05) and cleft glycosidic bonds of ${\beta}$-glucan resulting in lower the molecular weight. These results indicate that the use of ${\gamma}$-irradiation on ${\beta}$-glucan may be useful for improving its immunological activity by lowering the molecular weight of ${\beta}$-glucan.