• Journal of Radiation Industry
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• v.6 no.2
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• pp.119-123
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• 2012

The detection properties of gamma-irradiated (0~10 kGy) dried seaweed, dried shrimp, and seasoned dried filefish were investigated by photo-stimulated luminescence (PSL) and electron spin resonance (ESR). PSL could be used as a detection method on irradiated dried seaweed and dried shrimp as they showed photon counts greater than 5,000 counts/60 s (positive) in the irradiated samples with doses above l kGy. However, PSL could not be applied to detect irradiated seasoned dried filefish, because gamma-irradiated sample at 10 kGy even yielded photon counts less than 700 counts/60 s (negative). The ESR spectroscopy for only dried shrimp revealed specific signals derived from free radicals captured in the shell of shrimp. As a result, it is considered that PSL or ESR methods for detection of gamma-irradiated dried shrimp and only PSL can be used to detect gamma-irradiated seaweed. Furthermore, it is considered that hydrocarbon analysis of seasoned dried filefish containing fat by GC/MS and Thermo Luminance (TL) analysis of dried seaweed should be studied for detection of irradiation.

• Food Science and Preservation
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• v.18 no.3
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• pp.294-301
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• 2011

The aim of this study was to investigate the changes in identification markers of irradiated foods after treatment of the full-overlapped gravitational field energy (FGFE). Wheat and soybean samples were irradiated at 0-5 kGy of Co-60 gamma energy, and analyzed for photostimulated and thermo luminescence characteristics (PSL and TL) and sprouting rate at 0 and 6th month after FGFE treatment. As a screening method for irradiated samples, PSL photon counts (PCs) for the non-irradiated samples appeared negative (<700 PCs), while irradiated samples gave positive (>5,000 PCs). But FGFE-treated irradiated samples appeared intermediate (700-5,000 PCs), showing decreased PCs during storage. The TL analysis on irradiated samples exhibited glow curve peaks in range of $150-200^{\circ}C$ and TL ratio ($TL_1/TL_2$) was also >0.1. Therefore, identification of irradiated samples was possible using thermoluminescence. But the glow curve range of FGFE-treated irradiated samples shifted from $150-200^{\circ}C$ to $180-230^{\circ}C$ and TL intensity was decreased 37-60% resulting from FGFE treatment. After 6 months of storage, all the samples showed a decrease in TL intensity, but identification was still possible. The sprouting rate of irradiated samples decreased by about 72%, whereas that of FGFE-treated irradiated samples showed by about 85%, as compared to non-irradiated samples. More detailed study is required to investigate sprouting phenomena for FGFE-treated samples.

• Korean Journal of Food Science and Technology
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• v.49 no.3
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• pp.252-257
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• 2017

In this study, the physicochemical properties of irradiated (gamma-ray and electron-beam) soybeans with different processing (dry and powder) and origins (Korea, China, and USA) were investigated and compared. The results of photostimulated luminescence (PSL) screening indicated that all non-irradiated soybeans showed photon counts (PCs) ${\leq}700$, while all irradiated soybeans showed positive values-gamma-ray 5,815-39,591 count/min; electron beam 5,791-60,055 count/min. The results of thermoluminescence (TL) analysis of all irradiated soybeans indicated that the $TL_1$ glow curves exhibited maximum peaks at 150-250. TL ratio of irradiated samples was ${\geq}0.1$; therefore, the clear identification of irradiated samples was guaranteed by analysis of the $TL_1$ curve shape and TL ratios. The results of electron spin resonance (ESR) signal of 3 irradiated and dried soybeans showed two side peaks mutually spaced at 6.0 mT (cellulose radical). Non-specific signal was detected for all irradiated soybean powders; hence, ESR analysis could not be performed.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.227-231
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• 2004

Green, black and oolong teas were irradiated by $^{60}$ Co-gamma rays (0～10 kGy) and were investigated for detection of irradiation treatment using pulsed photostimulated luminescence (PPSL) and thermoluminescence (TL) during storage. Teas irradiated at 2.5 kGy or more showed a photon count of greater than 5000 counts/60 sec while the non-irradiated yielded only 650～1000 count/60 sec. Correlation coefficients between irradiation dose and photon counts/60 sec were 0.8951, 0.7934 and 0.9007 for green, black and oolong teas, respectively. The TL glow curves for minerals isolated from the non-irradiated teas were situated at about 30$0^{\circ}C$ with a low intensity, but for irradiated samples were approximately 15$0^{\circ}C$ with a high intensity. The TL ratios (TL$_1$/TL$_2$), calculated from values after initial radiation and then after re-irradiation of the teas, were below 0.1 for the non-irradiated samples and higher than 1.44 for all irradiated samples, enhanced the reliability of the identification results for TL. The signal intensity of PPSL and TL for irradiated teas decreased with the lapse of post-irradiation storage time at room temperature but was still distinguishable from that of the non-irradiated samples even after one year.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1236-1247
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• 2014

Gamma irradiated-treatment of natural medicinal plants can be used to improve extraction transference number and for qualitative improvement of color when applied to functional material exploration. This study investigated the biological activities of Aralia elata cortex extracts upon gamma irradiation. In addition, different physical techniques [photostimulated luminescence (PSL) and thermoluminescence (TL)] were used for irradiation identification of Aralia elata cortex. In PSL analysis, non-irradiated (0 kGy) sample showed a negative result of 400 photon counts (PCs), whereas irradiated (5, 10, and 30 kGy) samples showed positive results of 90,100.00, 312,614.33, and 321,661.67 PCs, respectively. In the TL method, growth curve showed very unusual behaviors around $200^{\circ}C$ upon natural-irradiation of the non-irradiated (0 kGy) sample and around $150{\sim}250^{\circ}C$ for the irradiated (5, 10, and 30 kGy) samples. The TL ratio was 0.1 in non-irradiated samples at 0.011, whereas the values of irradiated samples (5, 10, and 30 kGy) were 0.1 at 1.105, 1.009, and 2.206, respectively. For phenolics of gamma-irradiated Aralia elata cortex, water and 50% ethanol extracts had the highest amounts, $17.30{\pm}0.40mg/g$ and $18.87{\pm}0.46mg/g$ at 10 kGy irradiation, respectively. The inhibitory activities of angiotensin-converting enzyme and xanthin oxidase were higher in both irradiated water and 50% ethanol extracts than in non-irradiated ones. For pancreatin ${\alpha}$-amylase and ${\alpha}$-glucosidase inhibitory activities, water and 50% ethanol extracts containing $200{\mu}g/mL$ of phenolics showed high inhibitory activities of 60~100% at all irradiation doses (0~30 kGy). This result confirmed that Aralia elata cortex extracts have greater anti-diabetic effects than acabose as a diabetic remedy. Gamma-irradiated Aralia elata cortex extracts are useful as a functional material with anti-diabetic effects. Thus, Aralia elata cortex extracts can be used as a functional material with various biological activities, and gamma-irradiation can be used to amplify biological activities in plants.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.167-173
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• 2013

Dried fish products, such as seasoned cuttlefish, anchovy, and filefish, were analyzed to investigate the physicochemical quality and luminescence properties following gamma-irradiation. The overall color difference slightly increased in all irradiated samples, showing significant changes in Hunter's L, a, and b color values. Cuttlefish and filefish showed higher values in hydrophilic browning, whereas anchovy showed a higher value in lipophilic browning. The brown color intensity of filefish showed a dose-dependent increase. The thiobarbituric acid (TBA) value significantly increased in irradiated samples of cuttlefish and anchovy, which have relatively high lipid contents. Irradiated samples, except anchovy, were not suitable for screening using photostimulated luminescence (PSL) because only negative or intermediate values were observed. Thermoluminescence (TL) measurements were suitable for all fish samples, i.e., irradiation-specific glow curves were obtained, signal intensity increased, and the TL ratio fulfilled the criterion. There was no significant difference among the irradiated samples with regard to the sensory properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.581-591
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• 2017

The purpose of this study was to examine the biological activities of gamma-irradiated Teucrium veronicoides. In photostimulated luminescence analysis, non-irradiated sample showed lower than 700 photon counts (PCs), whereas irradiated (5 and 10 kGy) samples showed higher than 700 PCs. The thermoluminescence ratio of non-irradiated samples was less than 0.1, whereas the values of irradiated samples were greater than 0.1. Electron spin resonance analysis was performed confirmed for irradiation identification. The total phenolic contents of hot-water and 50% ethanol extracts were higher than those values after irradiation at 10 kGy. Regarding 1,1-diphenyl-2-picrylhydrazyl radical inhibitory activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, antioxidant protection factor, thiobarbituric acid reactive substance inhibitory activity as antioxidant test and xanthine oxidase inhibitory activity, the effect of gamma irradiation had on significant effects. On the other hand, ${\alpha}-amylase$ inhibitory activity of 10 kGy-irradiated hot-water extract was 23.6% higher than that of the non-irradiated sample. Thus, gamma irradiation could be used for the long-term storage of Teucrium veronicoides.