Effect of Animal Age on the Tenderness of Selected Beef Muscles

The tenderness of 12 beef muscles from animals of 8 different age groups (ranging from 1 to about 60 months old) which were treated to minimize pre‐rigor myofibrillar shortening, have been assessed using objective and subjective methods. The mean tenderness of these 12 muscles significantly (p<0.001) decreased with age. The rate of increase in the toughness of individual muscles with animal age was related to their connective tissue strength. Psoas major muscles were almost unaffected by increasing animal age whereas high connective tissue strength muscles, such as the Biceps femoris, trebled in toughness. A comparison of the different muscles revealed that one of the least representative was the often used M. longissimus dorsi.