DOSE DETERMINATION IN IRRADIATED CHICKEN MEAT BY ESR METHOD (1995)

(MSc. Thesis, Hacettepe University)

In this work, the properties of the radicals produced in chicken bones have been investigated by ESR technique to determine the amount of dose applied to the chicken meats during the food irradiation. For this goal, the drumsticks from 6-8 weeks old chickens purchased from a local market were irradiated at dose levels of 0; 2; 4; 6; 8 and 10 kGy. Then, the ESR spectra of the powder samples prepared from the bones of the drumsticks have been investigated. Unirradiated chicken bones have been observed to show a weak ESR signal of single line character. ionic radicals of axial symmetry with  g_||=1.9973 and g_^=2.0025 were observed to be produced in irradiated samples which would give rise to a three peaks ESR spectrum. In addition, the signal intensities of the samples were found to depend linearly on the radiation dose in the dose range of 0-10 kGy.

The powder samples prepared from chicken leg bones cleaned from their meats and marrow and irradiated at dose levels of 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20 and 22 kGy were used to get the dose-response curve. It was found that this curve ha biphasic character and that the dose yield was higher in the 12-18 kGy dose range and a decrease appears in this curve over 18 kGy. The radical produced in the bones were found to be the same whether the radiation was performed after stripping the meat and removing the marrow from the bone or before the stripping.

The ESR spectra of both irradiated and non irradiated samples were investigated in the temperature range of 100 K-450 K and changes in the ESR spectra of radical have been studied. For was increased. The same investigation has been carried out for irradiated samples and it was concluded that the signal intensities relative to the peaks of the radical spectrum increase in the temperature range of 100 K-330 K, then they decrease over 330 K. The change in the signal intensity observed over 330 K was found to have an irreversible character. non irradiated samples (controls), the signal intensities were found to decrease when the temperature

At the end of five months study, it was found that radicals produced in chicken bone were very stable and therefore it was concluded that chicken bone can be used as a dosimetry material.

At the end of this work, a simulation procedure has been carried out for irradiated chicken bone ESR spectra to determine the spectral parameters of ionic radical. The values obtained for these parameters were found to be in a good agreement with those found in the literature for the same radical

Many samples were irradiated at the same dose level and the ESR spectra were recorded to calculate the errors due to the settlement of the samples in the spectrometer and to the adjustment of the spectrometer. The standard deviations for measured signal intensities were calculated to determine the reliability limits of the numerical results obtained in this work for chicken bone.