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Structural and ultrastructural changes of full‐cycle cultured Pacific bluefin tuna ( Thunnus orientalis ) muscle slices during chilled storage
Author(s) -
Roy Bimol Chandra,
Ando Masashi,
Itoh Tomohiro,
Tsukamasa Yasuyuki
Publication year - 2012
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.5542
Subject(s) - myofibril , myofilament , ultrastructure , sarcomere , tuna , thunnus , anatomy , chemistry , breaking strength , biophysics , biology , microbiology and biotechnology , myocyte , biochemistry , materials science , fishery , fish <actinopterygii> , composite material
Background: This study examined the structural and ultrastructural changes of dorsal and ventral muscle tissues of full‐cycle cultured Pacific bluefin tuna (PBT), Thunnus orientalis Temminck & Schlegel 1844, cut into slices simulating sashimi and placed in chilled storage for varying periods. Structural and ultrastructural changes were determined in order to understand the physical texture by breaking strength measurement. Results: Progressive deterioration of myofibril structure was observed during chilled storage (4 °C) of PBT muscle slices over 5 days post mortem . Muscle degradation included detachment between myofibres, detachment of the plasmalemma, disruption of mitochondria, loss of Z‐line density and alignment, cementation of myofibrils, loss of the hexagonal arrangement of thick versus thin myofilaments and migration of subsarcolemmal nuclei to intermyofibrillar spaces. Conclusion: Loss of myofibre‐myofibre adhesion, detachment of the plasmalemma and disruption of other components did not lower the breaking strength of PBT muscle. This provides evidence that the muscle breaking strength of PBT is not only associated with the detachment of myofibres or detachment of the plasmalemma. Other factors that produce cement‐like substances, such as cementation of the myofibrillar components and degradation of the sarcoplasmic reticulum, may also increase breaking strength. Copyright © 2011 Society of Chemical Industry