Abstract:

Objective: To explore the qualitative identification of irradiated tea through thermo-luminescence (TL) analysis. Methods: Silicate minerals from tea were isolated, collected and measured with TL dosimeter. A TL glow curve was established. The comparisons of integrated intensity, peak value and peak temperature of TL glow curve between unirradiated tea and irradiated tea samples at different irradiation dosages were made. Results: The integrated intensity of TL glow curves of unirradiated tea samples was less than 50; the peak value did not exceed 0.4, and the peak temperature was more than 260 ℃. However, the integrated intensity of TL glow curves of irradiated tea samples was larger than 50000; the peak value was higher than 600, and the peak temperature was in the range of 160 to 190 ℃. Conclusion: TL analysis method can discriminate irradiated tea and unirradiated tea well. This method is very useful, especially for samples that can not be irradiated at the reference dosage.

Key words: thermo-luminescence, food irradiation, identification of irradiated food