Determination of Γ-Radiation Induced Products in Free and Peptide Bound Tryptophan

Conservation of food by ionizing radiation has become legally accepted in 37 countries of the world. Although some methods for the identificaton of irradiated food have been developed, there is a deficit in the detection of the irradiation in food with a high protein content. Up to now, only a single method based on the detection of o- and m-tyrosine which develop in addition to the physiologically formed p-tyrosine during the radiation induced hydroxylation of phenylalanine, has been developed (Chuaqhi-Offermanns and McDougall, 1991). Corresponding to this method we wished to find some irradiation induced products of tryptophan which could serve as markers for irradiated food with a high protein content.