Non-enzymatic weakening of myofibrillar structures during conditioning of meat: calcium ions at 0.1 mM and their effect on meat tenderization.

The tenderness of meat is set by the properties of connective tissue and myofibrils. Skeletal muscle connective tissues become firm with chronological aging concomitantly with the increase in intermolecular non-reducing cross-links of collagen, and this process toughens meat, however, connective tissues hardly change during conditioning of meat. Therefore, the tenderization of meat during post mortem aging, or to put it more precisely, during post rigor aging, stems for the most part from changes in myofibril structures. My research derives its origin on findings of two kinds of post mortem changes in myofibril structures; i) fragmentation of myofibrils; and ii) restoration of rigor-shortened sarcomeres. These results were published in 1967 [1], and were, thereafter proved by many workers to be closely related to meat tenderization. I report in this paper the essential molecular mechanisms of these phenomena, and of structural changes in connectin or titin filaments. All of them are non-enzymatically induced by 0.1 mM calcium ion, which is the ultimate concentration of sarcoplasmic calcium ion in post mortem muscles.