Characteristics of muscle from two species of bigeye snapper, Priacanthus tayenus and Priacanthus macracanthus

Composition and some properties of muscle from two species of bigeye snapper, P. tayenus and P. macracanthus, were investigated. Both species had a similar composition with the same myofibrillar protein content. However, muscle proteins from P. tayenus had higher thermal stability than those from P. macracanthus, as indicated by the higher enthalpy for transitions as well as the lower inactivation rate constant (K-D). Upon 15 days of iced storage, natural actomyosin Ca2+-ATPase and Mg2+-Ca2+-ATPase activities decreased, whereas Mg2+-EGTA-ATPase activity increased, suggesting the denaturation of myosin, actomyosin and troponin/tropomyosin complexes, respectively. Increased surface hydrophobicity and decreased sulfhydryl groups indicated the denaturation possibly occurred via hydrophobic interaction and disulfide formation. Heading and eviscerating of fish retarded the denaturation and physicochemical changes of proteins during iced storage. The results indicated that a rapid and proper post harvest handling was of importance to maintain the muscle quality of bigeye snapper.