Thermoluminescence analysis can identify irradiated ingredient in soy sauce before and after pasteurization

摘要

Thermoluminescence (TL) analysis was conducted to identify small quantities (0.5%, 1%, and 1.5%) of gamma ray-or electron beam-irradiated garlic powder in a soy sauce after commercial pasteurization. The sauce samples with gamma ray- and electron beam-irradiated (0, 1 or 10 kGy) garlic powder showed detectable TL glow curves, characterized by radiation-induced maximum in the temperature range of 180-225 degrees C. The successful identification of soy sauces with an irradiation history was dependent on both the mixing ratio of the irradiated ingredient and the irradiation dose. Post-irradiation pasteurization (85 degrees C, 30 min) caused no considerable changes in TL glow shape or intensity. Interlaboratory tests demonstrated that the shape and intensity of the first TL glow curve (TL1) could be a better detection marker than a TL ratio (TL1/TL2).