ABSTRACT 



Preliminary results from the analytical use of spectral reflectance in the study of the "greening" 

 condition in precooked yellowfin tuna are reported. It was found possible to predict tendency to 

 greening fronn laboratory precooking. The preliminary conclusions were that color changes in tuna 

 are the results of oxidative changes in the hennoglobin and myoglobin pignnents of the flesh, and that 

 differences in color, including greening, result from differences in the concentration of these pig- 

 ment derivatives. A relatively higher concentration of methemoglobin or metmyoglobin in raw fish 

 flesh seems to be indicative of a tendency to greening on precooking. 



