• Proceedings of the Korean Nutrition Society Conference
• /
• 2001.05a
• /
• pp.200.2-200
• /
• 2001

• Preventive Nutrition and Food Science
• /
• v.6 no.3
• /
• pp.152-157
• /
• 2001

Accumulated photon counts in immediate measurement after irradiation of marjoram, basil and thyme were shown to be below 625$\pm$162, 577$\pm$178 and 1261$\pm$640 Pc, respectively. The accumulated photon counts increased linearly with increasing irradiation doses up to 5 kGy and slightly increased from 5 kGy to 10 kGy. This trend was similar after storage periods. According to storage conditions, the difference of the accumulated photon counts was net clearly observed. The accumulated photon counts of irradiated spice samples decreased with increasing storage periods. The rate of decrease was higher in 5 and 10 kGy irradiated samples than that in 1 kGy, and in room conditions than that in darkroom conditions. The photon counts of the irradiated spice samples measured for 120 s were higher than those measured for 60 s. The irradiated spice samples showed higher photon counts than those of unirradiated samples in both room and darkroom conditions during all the storage periods. These results indicate that detection of irradiation was still possible after 24 weeks, although the PPSL signal of all spice samples decreased with increasing storage times.

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