Radiation- and grinding-induced luminescence properties for the detection of irradiated wheat

Abstract

Please cite this article in press as: Shahbaz, H wheat, Journal of Cereal Science (2013), http Wheat (Triticum aestivum L.) and wheat flour were some of the first foods the US Food and Drug Administration (FDA) approved for irradiation. In 1968, the FDA approved irradiation for US wheat and flour to control insects. The maximum approved irradiation dose for wheat and wheat flour is 0.5 kGy (IFT, 1998). However, there is no general consensus for applied international regulations and consumer acceptance of irradiated foods, and reliable analytical techniques to characterize the irradiation status of foodstuffs are highly desired. Among some of the tests, two luminescence techniques, photostimulated luminescence (PSL) and thermoluminescence (TL) have been standardized by the European Union as screening and confirmatory methods, respectively. Radiation-specific PSL and TL properties are due to the charge trapping process in the crystal structures of contaminating inorganic (silicate) minerals (Akram et al., 2012; Kim et al., 2012). Grinding is a common process in wheat processing (DobladoMaldonado et al., 2012). Application of mechanical stress due to the grinding can result in a change in the luminescence properties of the contaminating inorganic minerals (Aman and Tomas, 2004; Garcia-Guinea and Correcher, 2000; Toyoda et al., 2000). Ahn et al. (2012a) studied the effect of light conditions such as sunlight, artificial light, and a dark room on the luminescence characteristics