Radiation-induced changes in the patterns of free ninhydrin-reactive substances of meat.

Abstract

Samples of minced lean beef and pork, breast muscle of chicken, and white meat of carp packed in polyethylene/Hostaphan bags were irradiated in the presence of air at about 25 °C with 10-MeV electrons. The doses applied were for beef 0.5–20 Mrad, and for other meat samples 10 Mrad. In the dose range of 0–5 Mrad, no statistically significant changes in the composition of the free amino acids and similar compounds usually present in beef were found. In the dose range between 10 and 20 Mrad a tendency towards small losses in such components became obvious. In beef samples irradiated at doses ≧ 0.5 Mrad a new substance (Y) appeared distinctly in the zone of the basic amino-acids. This compound was detected by two independent methods, column chromatography and high-voltage electrophoresis. The yellow colour of the band appearing above carnosine in the pherogram was striking. SubstanceY was also found after irradiation of pork and chicken meat. At a dose of 10 Mrad the concentration ofY in white chicken meat was nearly three times higher than in beef and pork. After irradiation of white carp muscle noY, but another new basic compound (X) was observed. In the pherograms it appeared as a brownish-red band aboveβ-alanine. The irradiation productsX andY may be used to find out whether meat of animals as used in this investigation had been exposed to radiation, if doses of 0.5 Mrad or higher were applied.