title: Characterization of radiation-induced luminescence properties and free radicals for the identification of different gamma-irradiated teas.
abstract: Two kinds (20 each) of gamma-irradiated (0, 5, and 10 kGy) tea samples, blended powders and packed in sachets (tea bags), were investigated using photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance spectroscopy (ESR) to identify their irradiation status. PSL-based rapid screening was possible for all the control samples except for one packed and two powdered samples. The irradiated samples presented a good dose-dependent PSL count except two powdered samples with very low PSL sensitivity. TL analysis provided the most reliable results, in which all the irradiated samples were identified using a well-defined high-intensity TL glow curve in a temperature range of 150-250 °C. The TL results were also confirmed by determining the TL ratio (TL1/TL2), which was <0.1 in all the non-irradiated samples and >0.1 in the irradiated ones. ESR spectroscopy was effective for only 3 packed and 6 powdered samples showing the radiation-induced cellulosic and sugar radical signals, respectively.
authors.affiliation: School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea. jhkwon@knu.ac.kr
authors.forename: Joong-Ho
authors.initials: JH
authors.lastname: Kwon
authors.forename: Jae-Jun
authors.initials: JJ
authors.lastname: Ahn
authors.forename: Kashif
authors.initials: K
authors.lastname: Akram
authors.forename: Ik-Jae
authors.initials: IJ
authors.lastname: Son
authors.forename: Sang-O
authors.initials: SO
authors.lastname: Lee
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005514:Food Irradiation / Q000379:methods*; D005609:Free Radicals / Q000032:analysis*; D005720:Gamma Rays; D049449:Luminescence; D008163:Luminescent Measurements; D013662:Tea / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D005609:Free Radicals; D013662:Tea