Studies in Meat Tenderness 8. Ultra‐structural Changes in Meat During Aging

Abstract

SUMMARY: During the aging of beef, the external loading required to stretch sterno‐ mandibularis muscle to its fullest extent declines 5‐10‐fold from the maximum of 2 Kg/cm 2 muscle attained at rigor onset. This loss of tensile strength is due to a weakening of the myofibrillarstructures at the junction of the I filaments with the Z discs of the sarcomeres. The Z discs undergo progressive changes and lose ground substance as aging proceeds. There is no obvious structural change in the I filaments during aging although a weakening in the association of the constituent proteins of these structures apparently occurs.