Photo- and thermally stimulated luminescence of polyminerals extracted from herbs and spices

E.CRUZ-ZARAGOZA; J. MARCAZZÓ; V. CHERNOV; M. BARBOZA-FLORES

Montreal

Congreso; 16th Global Forum of the International Radiation Processing Community; 2011

Food irradiation is a well-accepted method to reduce foodborne diseases and to extend food shelf-life by inhibiting the growth of microorganisms. This technology has become a good alternative over others techniques, like the use of chemical gases which may result dangerous for humans and environment. Several methods based on the detection of physical, chemical and microbiological changes that can occur during the food irradiation are used in order to classifying foods as irradiated or not-irradiated. Among the most widely used physical methods are photostimulated luminescence (PSL) and thermally stimulated luminescence or thermoluminescence (TL). This work focuses on the study of the TL and PSL properties of polyminerals extracted from several commercial herbs and spices previously irradiated for sterilization purposes. In particular, the PSL and TL properties of mint (Mentha spicata), cinnamon (Cinnamomum), chamomile (Matricaria recutita), paprika (Capsicum annuum L.), black pepper (Piper nigrum), coriander (Coriandrum sativum) and Jamaica flower (Hibiscus sabdariffa L.) were studied. The polymineral inorganic fraction was separated from the organic part. The X-ray diffraction (XRD) analysis was carried out in order to determinate the mineral composition of the samples. Polyminerals were exposed to different doses (50–400 Gy) and the measurements were carried out by using a Risø TL/OSL-DA-15 and Harshaw TLD3500 readers. The PSL and TL responses of the irradiated minerals have been studied and reported as a function of the absorbed dose, fading at room temperature and sunlight bleaching. The feasibility of using the PSL technique for irradiated food identification is them discussed.