Identification of irradiation in coded black pepper samples by different physical methods

International audienceThe experiment had been carried out on four black pepper samples coded A, B, C, D. Two physical methods (viscosimetry with two different sample preparation and electron spin resonance) were used to detect irradiated samples. Both viscosimetry preparation methods (10% for heat gelatinization, 8% for non heat gelatinization) showed significant differences in apparent viscosity of coded samples and gave similar results at the examined concentrations. However, heat gelatinization gives greater differences in viscosity between the different samples. All the examined methods showed that sample D was not irradiated, but samples A and C were irradiated. Regarding the results of viscosity measurements sample A and C had to be irradiated at about 8 kGy (according to the calculations of identification number from the literature and our experience). Sample B could have been irradiated at a very low level or long ago according to ESR results, but it was not irradiated according to the results of viscosimetry. Identification of irradiation >8 kGy in black pepper samples is possible using these methods after one month storage at ambient temperature. In well organised conditions all the measurements can be carried out in 3 h. The applied dose for coded black pepper samples were the following: A = 8 kGy, B = 0 kGy, C = 8 kGy, D = 0 kG