Postmortem Changes in Myofibrillar Proteins of Goat Skeletal Muscles

Abstract

Postmortem changes at 5C in myofibrillar proteins of longissimus dorsi (LD), biceps femoris (BF), semimembranosus (SM) and semitendinosus (ST) muscles and myofibrillar structure of LD muscle of goat were investigated. Muscle samples were immediately collected after killing, and from carcasses stored at 5C for 3, 6, 9, 12 and 20 days. The sodium dodecyl sulfate‐polyacrylamide gel electrophoresis of myofibrils indicated the appearance of a 30 kDa component, depending on the type of the muscles. A new 55 kDa component appeared in BF and SM muscles during postmortem. Titin I and nebulin also disappeared during storage. The disappearance of titin 1 and nebulin and the appearance of a 30 kDa component were confirmed by Western blot analysis. The Transmission Electron Microscopy studies showed that after 3 days postmortem, Z‐disks stayed unaltered. After 6 days postmortem, a little ultrastructural alteration was observed, and at 12 days postmortem a considerable degradation of Z‐disk ultrastructure was shown. The Z‐disk degradation, which results in the fragmentation of myofibrils and the appearance of 30 kDa components, is the major change observed in goat skeletal muscles during postmortem.

Muscle tissue structural changes and texture development in sea bream, Sparus aurata L., during post-mortem storage

“…This fact has been described by Engel and Banker (1986) in some myopathies in which autophagic mechanisms are excited. However, it has not been described in the above mentioned studies in fish, probably due to that the cited studies were carried out on the first post-mortem stages; neither in mammals, where some post-mortem studies were performed in more advanced stages (Nagaraj et al, 2005;Taylor et al, 1994;Taylor & Koohmaraie, 1998). In the present study autophagic vacuoles increased gradually from 5 days on.…”

“…At these advanced stages hexagonal arrangement of sea bream was less apparent and the fragmentation of the myofibers increased. In mammals, myofibrillar fragmentation increased continuously throughout the storage, and it occurred at the level of I-band (Nagaraj, Anilakumar, & Santhanam, 2005;Taylor et al, 1994;Taylor & Koohmaraie, 1998). In the present study, the fragmentation of the myofibrils appeared at different levels of the sarcomeres, although I-band showed the highest and more frequent alterations.…”

Effects of transportation during the hot season, breed and electrical stimulation on histochemical and meat quality characteristics of goat longissimus muscle

“…Myofibril fragmentation index has been used as an indicator of postmortem proteolysis in various and species (Lametsch et al. 2007) as it accounts for differences in the rate of postmortem tenderization of meat (Nagaraj et al. 2005).…”

Effects of transportation during the hot season and low voltage electrical stimulation on histochemical and meat quality characteristics of sheep longissimus muscle

“…Myofibrillar fragmentation index has been used as an indicator of postmortem proteolysis in various types of meat (Lametsch et al, 2007) and account for differences in the rate of postmortem tenderization of meat (Nagaraj et al, 2005). The latter authors concluded that structural changes occurring in meat after slaughter are generally believed to be caused by interactions of myofibrillar proteins in the muscle.…”