LOW DOSE GAMMA IRRADIATION OF BOVINE METMYOGLOBIN

SUMMARY Bovine metmyoglobin (MetMb) in a pure state, in several differing states of purity and in meat was irradiated with ionizing gamma rays. Irradiation caused the brown MetMb to convert to a red myoglobin pigment which is similar but not identical to oxymyoglobin (MbO₂). The formation of red pigment was accelerated at slightly basic pHs and under nitrogen atmospheres. Rate of red pigment formation is not dependent upon MetMb purity. Rate of red pigment formation in meat is identical to the rate of formation in buffered MetMb solutions. This study also demonstrated that gamma irradiation does alter MetMb structure. This alteration may be the loss of amide nitrogen from the protein.