• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.43-47
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• 2001

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose on the ESR signal intensity and to identify the stability of radicals after 9 weeks of storage in order to detect irradiated shellfishes. The irradiated shellfishes (short-necked clam, purplish washington clam, freshwater clam, jackknifed clam, scallop and hard-shell mussel) presented an asymmetric absorption in shape at $g_{1}$=2.002~2.003 and $g_{2}$=1.998. The strength of the ESR signal increased linearly with the applied doses (1~7 kGy). A highly positive correlation coefficients ($R^{2}$=0.9136~0.9896) were obtained between the irradiation dose and corresponding ESR signal intensity. The intensity of the signals after irradiation was stable even after 9 weeks of storage at 5$\pm$1$^{\circ}C$.

• Nuclear Engineering and Technology
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• v.32 no.3
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• pp.254-260
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• 2000

Electron spin resonance (ESR) spectroscopy was used to detect irradiated meat containing bones (chicken, pork and beef）, to investigate the effect of irradiation dose on the ESR signal intensity and to identify the stability of radicals under 9 weeks of storage. Chicken, pork and beef were irradiated with doses 0, 1, 3, 5 and 7 kGy at room temperature using a Co-60 irradiator. Bones were pieced and dried, which were placed in a quartz tube within an Electron paramagnetic resonance (EPR) spectrometer resonator cavity. The irradiated bone presented an asymmetric absorption in shape, different from that of a non-irradiated one. The signal intensity of smaller animals are lower than larger species. Variation was observed between samples of the same species depending on the calcification status of the bone. Moreover different irradiation doses produced different signal areas that make possible to estimate the absorbed dose of treated meat. The ESR signal stability after irradiation was stable in even after a 9 week storage at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.239-242
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• 2001

Electron spin resonance(ESR) spectroscopy was used to investigate the effect of irradiation dose on the ESR signal intensity of irradiated spices and to identify the stability of radicals after storage. Red, white and black peppers, and garlic powders were irradiated with doses of 0, 1, 5, 10, 20 and 30 kGy at room temperature using a Co-60 irradiator. Triplet ESR signals were observed in irradiated pepper powders, while singlet ESR signals were observed in irradiated garlic powders. Those characteristic signals were not detected in non-irradiated samples. The strength of ESR signals linearly increased with the applied doses(1~3 kGy). Highly positive correlation coefficients ($R^2$=0.9757~0.9933) were obtained between the irradiation doses and the corresponding ESR signal intensities. The signal intensities of irradiated samples were stable even after 97 days of storage at room temperature.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.2
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• pp.53-58
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• 2020

Free radicals including reactive oxygen species (ROS) are important chemicals in the research area of biology, pharmaceutical, medical, and environmental science as well as human health risk assessment as they are highly involved in diverse metabolism and toxicity mechanisms through chemical reactions with various components of living bodies. Electron spin resonance (ESR) spectroscopy is a powerful tool for detecting and quantifying those radicals in biological environments. In this work we observed the ESR signal of 2,2,6,6-Tetra-methyl piperidine 1-oxyl (TEMPO) in aqueous solution at various concentrations to estimate the uncertainty factors arising from the experimental conditions and signal treatment methods. As the sample position highly influences the signal intensity, dual ESR tube geometry (consists of a detachable sample tube and a position fixed external tube) was adopted. This type of measurement geometry allowed to get the relative uncertainty of signal intensity lower than 1% when triple measurements are averaged. Linear dependence of signal intensity on the TEMPO concentration, which is required for the quantification of unknown sample, could be obtained over a concentration range of ~10³ by optimizing the signal treatment method depending on the concentration range.

• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.248-251
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• 2000

Electron spin resonance (ESR) spectroscopy was used to detect irradiated chicken eggs, to investigate the effect of irradiation dose on the ESR signal intensity and to identify the stability of radicals under 77 days of storage. Raw chicken eggs were irradiated with doses of 0, 0.5, 1, 2, 3 and 5 kGy at room temperature using a Co-60 irradiator. The samples were prepared by separating, drying and powdering shells from the raw eggs. The irradiated chicken egg shells presented an asymmetric absorption in shape at g$_1$=2.0023$\pm$0.00004 and g$_2$=1.9979$\pm$0.00005, different from the non-irradiated ones. The strength of the ESR signal increased linearly with the applied doses (to S kGy). The intensity of the ESR signals after irradiation were stable even after 77-day of storage at 5$^{\circ}C$ and/or room temperature.

• Journal of Food Hygiene and Safety
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• v.15 no.1
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• pp.1-4
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• 2000

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose on the ESR signal intensity of irradiated crabs and the stability of these radicals under 9 weeks of storage. Swimming and small crabs were irradiated with doses of 0, 1, 3, 5 and 7 kGy using a Co-60 irradiator at ambient temperature. A claw, a walking leg and a cars- pace of the crab pieced and dried were placed in a resonant quart tube within an EPR X-band spectrometer. The irradiated crabs presented an asymmetric absorption in shape at g$_1$=2.002 $\pm$ 0.003 and g$_2$=1.998$\pm$0.005, and were different from the non-irradiated ones. The intensity of the ESR signals was greatest in the claw, intermediate in the carapace and lowest in the walking leg. Samples given low and high doses of irradiation could also be distinguished. The ESR signal after irradiation was stable, even after a 9-week storage.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.606-611
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• 1999

To identify irradiated foods, studies have been carried out with electron spin resonance (ESR) spectroscopy on bone containing foods, such as chicken, pork, and beef. Bones cleaned, pieced and dried were irradiated with doses of 0, 1, 3, 5 kGys using a $Co^{60}$ irradiator. The bones were placed in a resonant quartz tube with an internal diameter of about 4.0 mm within the Bruker Win-ESR spectrometer, and the intensity of the ESR signal could be quantified by double integration of the first derivative spectrum. The irradiated bone presented an asymmetric absorption in shape, different from that of an unirradiated one. It could be possible to detect at doses lower than 1 kGy below the dose employed commercially (3 kGy) in the case of irradiated chicken bone. The signal intensity was greatest in the beef bone, intermediate in the pork bone and lowest in the chicken bone; it was normally lower for smaller animals than for larger species, and small variations were observed between samples of the same species. The intensity of the signal induced in bones increased linearly with irradiation doses in the range of 1.0 kGy to 5.0 kGy, and it was possible to distinguish between samples given low and high doses of irradiation. The signal stability for 6 weeks made them ideal for the quick and easy identification of irradiated meats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1454-1459
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• 2012

An improved detection of radiation-induced paramagnetic faults was developed to identify the irradiation status of basil and clove. The effectiveness of different sample pretreatments, including freeze-drying (FD), oven-drying (OD), alcoholic-extraction (AE), and water-washing and alcoholic-extraction (WAE), were examined. All non-irradiated samples showed a single central signal ($g_0$=2.006), whereas radicals representing two additional side peaks ($g_1$=2.023 and $g_2$=1.986) with a mutual distance of 6 mT were detected in the irradiated samples. AE and WAE produced the best results for irradiated clove in terms of intensities of radiation-specific ESR signals and their ratios to the central signal. However, FD provided the highest intensities of radiation-specific ESR signals for basil, whereas their ratios to the major signal were better in the cases of AE and WAE. Signal noise, particularly due to $Mn^{2+}$ signals, was observed, whereas it decreased in AE and WAE pretreatments. Based on our results, AE and WAE can improve the detection conditions for radiation-specific ESR signals in irradiated samples.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.136-140
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• 2009

The verification of irradiation treatments, using dried garlic and cabbage treated at 0-20 kGy, was investigated by analyzing the photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence (TL) characteristics of the samples. The PSL results showed that the photon counts/60 sec of the non-irradiated dried garlic and cabbage were 287-337, corresponding to negative, while those of the irradiated samples were 7511-54063 photon counts/ 60 sec, corresponding to positive, making it possible to discriminate the non-irradiated from the irradiated samples. In ESR analysis, the dried garlic irradiated at 20 kGy exhibited cellulose radicals, whereas the irradiated dried cabbage showed crystalline sugar-induced multi-component signals, which were not found in the non-irradiated samples. The ESR signal intensity significantly increased as the irradiation dose increase ($R^2$= 0.9369 - 0.9926). The TL glow curves of the irradiated samples appeared at a temperature interval of 150-250, which were significantly different from those of non-irradiated samples, showing a significant increase in TL signal intensity with irradiation dose ($R^2$= 0.9670 - 0.9768). To enhance the reliability of the results, the first glow curve ($TL_1$) was compared with the second glow curve ($TL_2$) obtained after a re-irradiation step at 1 kGy. The TL ratio ($TL_1/TL_2$) was in good agreement with the reported TL threshold values for both the non-irradiated (<0.1) and irradiated (> 0.1) samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.609-614
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• 2002

The characteristics of thermoluminescence (TL) and electron spin resonance (ESR) and organoleptic qualities of gamma-irradiated raisin and dried banana were investigated during storage at 4$^{\circ}C$ for 6 months. The minerals separated from non-irradiated raisins showed TL glow curve (TL$_1$) with very low intensity around 200~30$0^{\circ}C$, while the irradiated samples at 1 kGy or more showed glow curves with higher intensity around 18$0^{\circ}C$, with linear increase by irradiation dose ($R^2$=0.9684), which made it possible to identify irradiated samples during 6 months. Moreover, TL ratios (TL$_1$/TL$_2$) through the reirradiation step at 1 kGy enhanced confidence in the identification of irradiated raisins. The ESR signals of multicomponent lines resulted from crystalline sugar radicals were shown in irradiated banana, identifying irradiated samples. The ESR signal intensity was dependent on irradiation doses ($R^2$=0.8977) and the signals were stable enough to be detected by 6th month after storage. Considering tile marketability of irradiated dried fruits during 6 months at low temperature TL and ESR analyses were shown suitable for the identification of irradiated raisins and dried banana, respectively.