The Concentration of Myoglobin and Hemoglobin in Tuna Flesh

SUMMARY Amounts of myoglobin and hemoglobin were determined in light and dark muscle of yellowfin tuna, Neothunnus macropterus. Myoglobin concentration ranged from 0.37 to 1.28 mg/g wet weight in light muscle and from 5.3 to 24.4 mg/g in dark muscle; hemoglobin concentrations ranged from 0.12 to 0.58 mg/g in light muscle and from 0.5 to 3.8 mg/g in dark muscle. The fish were divided into two groups on the basis of means of capture, i.e., taken on hooks from a bait boat, or seined. Average percentage of hemoglobin was slightly, but not significantly, higher in the seined fish. Of the total heme pigments, myoglobin constituted 69–85% in light muscle and 81–95% in dark muscle from bait-boat fish, and 47–81% in light muscle and 84–98% in dark muscle of seined fish.