Identification Characteristics of Irradiated Dried-Spicy Vegetables by Analyzing Photostimulated Luminescence (PSL), Thermoluminescence (TL) and Electron Spin Resonance (ESR)

The identification characteristics of inadiated dried onion and garlic at 1, 4 and 7 kGy were investigated by analyzing their photostimulated luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR). The PSL results showed that the photon counts of non-irradiated dried onion were less than 700 (negative) and those of irradiated samples at 1kGy or more were over 5000 (positive), making it possible to discriminate non-irradiated onions from irradiated ones. However, the intermediate counts (700-5000) were observed in irradiated garlic at 1 and 4 kGy, even though positive counts were measured in 7 kGy group. Radiation-induced TL glow curves were measured at range in both irradiated onion and garlic samples at 1 kGy or more, which could identify irradiated groups. Furthermore, determination of TL ratios for both samples could verify the above results. It was found, however, that ESR spectroscopy was not suitable for the detection of irradiated dried onion and garlic.