• Korean Journal of Food Science and Technology
• /
• v.42 no.6
• /
• pp.648-652
• /
• 2010

This study was performed to investigate PSL and TL characteristics for the detection of different ratios of gamma-irradiated turmeric. It was possible to determine PSL and TL of 1- and 10-kGy irradiated turmeric. The TL ratios ($TL_1/TL_2$) of non-irradiated samples were lower than 0.001, while those of irradiated samples were higher than 0.355. In the PSL results, blended samples containing irradiated ingredients showed intermediate values for a 1% blending rate. Furthermore, TL analysis of blended samples seems to offer a promising method for irradiation identification by TL glow curve form and temperature range. The 1- and 10-kGy irradiated samples were able to be detected above a 4% blending rate. However, the TL ratio appeared as a threshold value below 0.1 for irradiated samples. Overall, TL analysis identified 4% blended samples containing gamma-irradiated turmeric.

• Food Science and Biotechnology
• /
• v.18 no.2
• /
• pp.374-378
• /
• 2009

Three physical methods, photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR), have been applied to detect the irradiation treatment for the non- and steamed sesame seed samples. PSL successfully screened the irradiated samples from the non-irradiated control by comparing their photon counts (PCs) with the lower (less than 700 count/60 sec) and upper threshold values (higher than 5,000 count/60 sec). TL signals were still detected in all irradiated samples even after steaming, which was reconfirmed with TL ratios [integrated area of $TL_1$ (the first glow)/$TL_2$ (the second glow)] through re-irradiation step. ESR spectrometry showed that radiation-induced cellulose radicals were detected in all the irradiated samples irrespective of steaming treatment. Identification of the irradiated sesame seeds was possible even after steaming by analyzing PSL, TL, and ESR.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.11
• /
• pp.1529-1533
• /
• 2008

The detection characteristics of gamma-irradiated ($0{\sim}10.0\;kGy$) medicinal herbs (Platycodon grandiflorum, Acanthopanax chiisanensis) were investigated by photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR). The results of the PSL, a first screening method in comparison with the TL, showed photon counts greater than 5,000 counts/60 s (positive) in the irradiated samples, while the non-irradiated samples yielded photon counts less than 700 counts/60 s (negative). The TL was also applied for the detection method of irradiated medicinal herbs and showed that the non-irradiated sample revealed a glow curve with a low intensity, while the irradiated samples showed a higher intensity. These results were normalized by re-irradiating the mineral grains with a irradiation dose of 1.0 kGy, and a second glow curve was recorded. The ratio of the intensity of the first glow curve ($TL_1$) to that after the normalization dose ($TL_2$) was determined and compared with the recommended threshold values. TL ratio ($TL_1/TL_2$) was below 0.007 for the non-irradiated sample and higher than 0.1 for all irradiated samples (above 1.0 kGy). ESR spectroscopy revealed specific signals (6.065 mT) derived from free radicals in cellulose containing irradiated medicinal herbs. The P. grandiflorum showed clearer signals than A. chiisanensis. From the results of our studies, the PSL, TL, and ESR determinations were found to be suitable for the detection of irradiated medicinal herbs such as P. grandiflorum and A. chiisanensis.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.11
• /
• pp.1569-1574
• /
• 2011

In this study, the identification of the irradiated seafood cooking drips from Hizikia fusiformis, Enteroctopus dofleini and Thunnus thynnus was conducted. The physical detection methods used included photo-stimulated luminescence (PSL) and thermoluminescence (TL), and the chemical detection methods were hydrocarbons analysis. In the PSL study, all seafood cooking drip samples showed 260~510 photon counts; thus, the PSL method could not be used for the detection of irradiated seafood cooking drips. The TL method could be used for the detection of irradiated H. fusiformis and E. dofleini cooking drips. In both cooking drips, the shapes of the glow curves indicated a specific peak at 150$^{\circ}C$~250$^{\circ}C$, which made it possible to identify the irradiated samples. The hydrocarbons derived by gamma irradiation of T. thynnus cooking drip were not detected due to low concentration and inconsistent content of fatty acids in the untreated T. thynnus cooking drip.

• Preventive Nutrition and Food Science
• /
• v.9 no.4
• /
• pp.317-323
• /
• 2004

Photostimulated Luminescence (PSL), Electron Spin Resonance (ESR) and Thermoluminescence (TL) analysis were conducted to detect irradiation treatment of imported whole and ground spices. The screening by PSL detected no irradiation treatment, except un the ground thyme and bay leaves which exhibited photon counts in the intermediate level. Irradiation of the two spices was detected after irradiating them at 1.0, 3.0, 5.0 and 10.0 kGy, and then subjecting them to PSL analysis, which resulted in the significantly low photons of non-irradiated spices compared to that at 1.0 kGy, indicating that the photon counts varied depending on the amount of inorganic mineral debris in the spices. To confirm a successful detection by using PSL, ESR and TL methods, some spices were selected, irradiated at 5.0 and 10.0 kGy, and subjected to the detection methods. PSL identified the irradiated spices except the cassia, which showed very weak PSL sensitivity, but was identified by ESR analysis. Also, the ESR and TL exhibited the typical signals induced by irradiation treatment and were able to successfully detect all of the irradiated spices. In addition, we found a positive correlation between the intensity of ESR and TL signals and irradiation doses.

• Korean Journal of Materials Research
• /
• v.13 no.6
• /
• pp.343-346
• /
• 2003

Photoluminescence(PL), photostimulated luminescence(PSL) and thermoluminescence(TL) in $SrC1_2$:$Eu^{2+}$ , $Na^{+}$ phosphor powder were measured, and the activation energies(trap depth) of traps associated with TL and PSL were investigated. The PL and PSL in the studied sample is due to the $4f^{6}$ 5d\longrightarrow$4f^{7}$transition of $Eu^{ 2+}$. TL glow curve is single peak, and its peak temperature is about 377.2 K. The PL, PSL and TL emission spectra of the phosphors are located in the range of 380∼440 nm, peaking at 408 nm. The activation energy of the PSL trapping center is 0.78 eV and that of the TL trapping center is 0.79 eV. We, thus, suggest that the trapping centers giving rise to the PSL are identical to those giving rise to the TL.

• Journal of Radiation Industry
• /
• v.6 no.4
• /
• pp.305-310
• /
• 2012

This study examined radiation detection properties of imported perilla seeds, almonds, and soybeans. Food samples were irradiated at doses of 0.5, 1, 2, and 4 kGy and analyzed by photo-stimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR). The results of PSL showed that photon counts of irradiated perilla seeds and soybeans were $32,959counts{\cdot}60sec^{-1}$ and $7,234counts{\cdot}60sec^{-1}$, respectively, at an irradiation dose of 0.5 kGy, and the photon count of irradiated almonds was $5,581counts{\cdot}60sec^{-1}$ at an irradiation dose of 1 kGy. The results of TL showed that this technique is useful for detecting irradiated samples; the TL ratios ($TL_1/TL_2$) measured for the food samples at an irradiation dose of 0.5 kGy were 0.2301 for perilla seeds, 0.4595 for almonds, and 0.4827 for soy beans. Lastly, results of ESR spectroscopy for only soybeans revealed specific signals derived from free radicals captured in the cellulose. In conclusion, PSL, TL, and ESR methods can be used for the detection of gamma-irradiated soybean samples, whereas gamma-irradiated perilla seeds and almonds can be confirmed by a serial detection with a TL method after PSL.

• Food Science and Preservation
• /
• v.19 no.1
• /
• pp.37-46
• /
• 2012

The identification characteristics of irradiated (0.5, 1, 2, and 4 kGy) brown rice, soybean, and sesame seeds were investigated using photostimulated luminescence (PSL), thermoluminescence (TL), and hydrocarbon analysis during 12-month storage. PSL-based screening was possible for the irradiated soybean and sesame seed samples up to 6 and 12 months, respectively. The TL glow curve shape, intensity, and ratio enabled the clear dose-dependent discrimination of all the non-irradiated and irradiated samples. The TL intensity decreased during storage, but the TL glow curve did not change qualitatively, which provided enough information to confirm the irradiation treatment of the samples over the storage period. Radiation-induced hydrocarbons were found in all the irradiated samples even at 0.5 kGy, throughout the storage period. 8-Heptadecene ($C_{17:1}$) and 1,7-hexadecadiene ($C_{16:2}$) originated from oleic acid, and 6,9-heptadecadiene ($C_{17:2}$) and 1,7,10-hexadecatriene ($C_{16:3}$) originated from linoleic acid, can be used as radiation-induced markers in identifying irradiated brown rice, soybean, and sesame seeds.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.11
• /
• pp.1837-1842
• /
• 2013

Photostimulated luminescence (PSL) and thermoluminescence (TL) analyses were conducted for the detection of different gamma-irradiated dried fishes (mussel, squid, beka squid, mitra squid, plaice, and saury) at 0, 1, 5 and 10 kGy. For TL analysis, the contaminating silicate minerals were obtained by density separation or acid hydrolysis treatment. PSL determinations indicated that all the non-irradiated samples showed PSL photon counts/60 s (PCs) lower than 700 PCs (negative), but the irradiated mussel sample at 5 and 10 kGy were only possibility identified showing higher than 5000 PCs (positive). Irrespective of sample kinds and methods of mineral separation, all the non-irradiated samples showed TL glow curves in low-intensity with a maximum peak only after $250^{\circ}C$. However, all the irradiated samples produced TL glow curves in high intensity with a maximum peak particularly in the temperature range of 1$150{\sim}250^{\circ}C$. In conclusion, more distinguishable TL results [glow curve, TL ratio ($TL_1/TL_2$)] were obtained from the marker minerals separated by acid hydrolysis rather than density method.

• Korean Journal of Food Science and Technology
• /
• v.45 no.1
• /
• pp.8-12
• /
• 2013

Photostimulated luminescence (PSL) and thermoluminescence (TL) analyses were conducted for the detection of different irradiated dried fishes. All the non-irradiated samples provided PSL counts of lower than 700 (negative: $T_1$). Clear identification of irradiated sample was only possible for irradiated anchovy with PSL counts >5000; however, the results were unsatisfactory (not positive) for irradiated cod, dried filefish, hairtail, and herring samples. The contaminating silicate minerals were obtained by density separation or acid hydrolysis to perform TL analysis, which resulted in a low intensity of TL glow curve with a maximum peak after $250^{\circ}C$ for the non-irradiated samples that are irrespective of their kinds and methods for the mineral separation. The TL glow curves of high intensity with maximum peak in the temperature range of $150-250^{\circ}C$ were observed for all the irradiated samples. However, better results of TL glow curves and particularly of the TL ratio ($TL_1/TL_2$) were obtained when the minerals were separated by a acid hydrolysis method.