Hemoglobin
Normally, hemoglobin contributes less to the appearance of
seafood than myoglobin because it is lost easily during handling
and storage, while myoglobin is retained in the intracellular
structure. The amount of hemoglobin present also affects to
a greater extent the color appearance of light red and dark red
muscles of red-meat fish flesh (Wang and Amiro 1979). For example,
in yellowfin tuna Neothunnus macropterus, hemoglobin
concentrations ranged from 12 to 50 mg% in light red muscle
and 50 to 380 mg% in dark red muscle (Livingston and Brown
1981). The amount of residual hemoglobin in fish muscle is obviously
influenced by the bleeding efficacy at the time of catch.
Method of catch also affects the residual hemoglobin in the fish
muscle. For example, the percent of total heme as hemoglobin
in the meat of yellowfin caught by bait boat and purse seine was
24% and 32%, respectively (Barrett et al. 1965).
The green meat of raw or frozen broadbill swordfish (Xiphias
gladus) is believed to be due to the combination of hemoglobin
with hydrogen sulfide generated from the fairly extensive decomposition
of the meat (Amano and Tomiya 1953).