Study of photostimulated- and thermo-luminescence characteristics for detecting irradiated kiwifruit

J Agric Food Chem. 2008 Feb 27;56(4):1180-3. doi: 10.1021/jf072568y. Epub 2008 Feb 2.

Abstract

Photostimulated luminescence (PSL) and thermo-luminescence (TL) analyses were conducted to detect irradiated kiwifruits. Samples were irradiated with Co-60 gamma-rays at 0-2 kGy. The freeze-dried kiwifruit peel showed 309 photon counts (PCs) for nonirradiated samples that accounted for less than the lower threshold value (700 counts/60 s, negative) and above 9306 PCs for 1 and 2 kGy-irradiated samples, which was higher than the upper threshold value (5000 counts/60 s, positive). However, PSL signals of irradiated samples remarkably decreased after 6 weeks of storage. The TL measurement using minerals isolated from the whole kiwifruit surface revealed a glow curve (TL 1) with a low intensity at 200-300 degrees C in nonirradiated samples but with a higher intensity at around 180 degrees C in irradiated samples at 1 kGy or more. The TL ratios, integrated areas of TL 1/TL 2 that was measured after 1 kGy re-irradiation for the TL 1-tested minerals, were less than 0.1 in nonirradiated samples and higher than 0.1 in irradiated ones and could verify TL 1 results. The inorganic dust minerals used were mainly composed of feldspar and quartz.

MeSH terms

  • Actinidia*
  • Food Analysis
  • Food Irradiation*
  • Fruit / chemistry*
  • Gamma Rays
  • Hot Temperature
  • Light
  • Luminescent Measurements / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Time Factors