Changes in the Fine Structure of the Myocommata–Muscle Fibre Junction Related to Gaping in Rested and Exercised Muscle from King Salmon ( Oncorhynchus tshawytscha)

• Published in: Food science & technology 1997-01, Vol.30 (3), p.246-252
• Main Authors: Fletcher, G.C., Hallett, I.C., Jerrett, A.R., Holland, A.J.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; cold storage; collagen; duration; exercise; fish; Fish and seafood industries; Food industries; food processing; food storage; freezing; Fundamental and applied biological sciences. Psychology; gaping score; membranes; microstructure; muscle fibers; muscle fibre; muscle tissues; Oncorhynchus tshawytscha; salman; salmon; shelf life; ultrastructure
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1006/fstl.1996.0175

Fillets of king salmon ( Oncorhynchus tshawytscha) were subjected to two defined levels of exercise and held for 0, 20, 40 or 120 h at 2 °C followed by storage at −30 °C for 1 d or 6 weeks to examine their propensity for gaping. We followed the gaping process by observing the interface between the muscle fibres and myocommata with transmission electron microscopy. The interface appeared as membrane-lined groove-like invaginations containing collagen fibres protruding into the muscle fibre bases. A successive loss of the lining from the invaginations, followed by the detachment of the sarcolemma/basal lamina complex from the muscle fibre base, was observed with increased storage and gaping. The primary determinant of gaping was the time in chill storage before freezing. Increased time in frozen storage resulted in slightly more gaping. Under laboratory handling conditions, the exercised fillets showed the same pattern of gaping as rested fillets when viewed either pre- or post-rigor.