The quality attributes, descriptive sensory characteristics, and muscle proteomes (sarcoplasmic and
myofibrillar) of normal and reddish channel catfish (Ictalurus punctatus) fillets were evaluated. Reddish
fillets had greater (p < 0.05) a*(redness) and b* (yellowness) values and lower L* (lightness) (p < 0.05)
than normal ones, but no differences existed (p > 0.05) in cooking loss and instrumental texture. The
reddish fillets were more (p < 0.05) bitter, earthy, grassy, metallic, and oxidized, and had more off-flavor
than normal ones, but was less (p < 0.05) sweet and juicy than normal fillets. Profiling of muscle proteomes
employing two-dimensional electrophoresis and mass spectrometry identified several myofibrillar
and sarcoplasmic proteins. The sarcoplasmic proteome revealed differential abundance of the beta
subunit of hemoglobin, which was over-abundant (p < 0.05) in reddish fillets. On the other hand, no
differences (p > 0.05) were observed in the abundance of myofibrillar proteome components. The results
indicated that the occurrence of red color defect in catfish fillets is primarily due to the over-abundance
of hemoglobin.