ABSTRACT 



Resulta are reported from a study of the "greening" condition that appears in certain samples of 

 yellowfin tuna on precooking. Evidence is presented that this is an actual color condition similar to 

 discoloring processes that occur in other meats, and is caused by an anomalous heme protein oxida- 

 tion. Related to this tendency to turn green on precooking are the presence of high concentrations of 

 metnnyoglobin, some denaturation, and a slightly high fat peroxide content in the raw nneat. In addi- 

 tion, green meat generally has a high flesh pignnent content. Oxygen starvation due to the exhaustion 

 of the fish that nnight occur in the process of catching does not seem to produce the factors that lead 

 to greening, but rather a deterioration that goes on even in the frozen state seems to be responsible. 

 Spectral reflectance was eniployed in much of the work and revealed important in situ changes or 

 processes in flesh pigments that would have been impossible to note by other means. 



