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Ultrastructural changes during frozen storage of cod ( Gadus morhua L.)
Author(s) -
JARENBÄCK L.,
LILJEMARK A.
Publication year - 1975
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1975.tb00025.x
Subject(s) - myofilament , myofibril , sarcomere , ultrastructure , shrinkage , sarcoplasm , anatomy , endoplasmic reticulum , biophysics , materials science , chemistry , composite material , myosin , myocyte , biology , microbiology and biotechnology , biochemistry
Summary The ultrastructure of myofibrils from cod white muscle has been studied using the freeze etching technique. Unfrozen post‐rigor samples were compared with thawed samples stored for a short period at −40°C and also with samples stored at −20°C for a period known to result in severe toughness. Transverse fractures from unfrozen muscle reveal the regular hexagonal arrangement of thick myofilaments and the vesicular material of the sarcoplasmic reticulum between the myofibrils. Muscle stored for a long period at −20°C shows, after thawing, disturbances in the hexagonal pattern and deformation of the sarcoplasmic reticulum. Longitudinal fractures both from unfrozen and frozen stored muscles sometimes reveal the arrangement of cross‐bridges between thick and thin myofilaments. Gross‐bridges lie at an angle to the thick filaments and their repeat along the filament can be seen. Measurements of distances between thick myofilaments showed a significant reduction in the interfilament spacing after prolonged frozen storage. This shrinkage together with the observed disorders within and between myofibrils may reflect an impaired ability to reabsorb water following thawing.