AN HPLC METHOD TO DETERMINE ORTHO-TYROSINE IN CHICKEN MEAT

The lack of analytical methods to establish whether or not a food product has been irradiated, and to what dose, if a major obstacle to the wider use of the food irradiation process. o-Tyrosine produced during irradiation of protein-containing foods appears to be a promising marker for this purpose. An HPLC/fluorescence method that allows accurate quantitation of 0.1 ng of o-tyrosine has been developed. The method involves freeze-drying of the sample, acid hydrolysis, solid-phase extraction, fractionation by HPLC, and, in some cases, a second chromatographic separation (HPLC) of the collected fraction. This method was used to determine the radiation dose yield of o-tyrosine in irradiated chicken breast. The results show that there is a linear relationship between the irradiation dose and the yield of o-tyrosine in irradiated chicken meat.