ILLUSTRATIONS 

 FIGURE Page 



1. Chromaticity coordinates for green and normal tuna meat. 2 



2. Variation of the 540/640 millimicron peak ratio with absorbancy at Soret peak (410-415 



millimicrons), an index of pigment content. 3 



3. Separation of aqueous extract of raw tuna into hemoglobin and myoglobin by phosphate 



fractionation 3 



4. Reflectance curves showing pigment mixtures found in raw tuna flesh. 4 



5. A. Simplified absorption curve showing increased concentration of nnethemoglobin with 



increasing oxy-he.moglobin. B. Similar simplified absorption curves showing 



increased metmyoglobin content after various periods of freezer storage. ... 4 



6. Oxidation of flesh pigment on treatment with nitrogen 5 



7. Reflectance curves showing denaturation by appearance of hemochrome band at 528 m(i 



after reduction with dithionite 5 



8. Reflectance curves showing solubility of metmyoglobin and insolubility of oxymyoglobin 



in raw tuna flesh 6 



9. Reflectance curves showing pigments of cooked tuna flesh. 6 



10. Spectral absorbance measured in transmission of extract of precooked green tuna flesh. 7 



11. Reflectance curves of acid-acetone and acid-methanol extracted precooked tuna of 



decreasing greenness. 8 



12. Relation of metmyoglobin content of raw tuna flesh to color rating of the sanne flesh on 



precooking. 9 



13. Relation of metmyoglobin content of raw fish flesh to color as objectively judged. . . 9 



