Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/1998
Publication Date: N/A
Interpretive Summary: It has been shown that beef production systems in the U.S. result in unacceptable variation in meat tenderness. Thus, the beef industry has placed a high priority on development of instrumentation for carcass measurements that accurately predict cooked meat tenderness. Recently, we developed methodology for accurately classifying beef into different tenderness groups. It is well established that beef tenderness decreases as degree of doneness increases and a large proportion of beef consumers cook their beef medium to very-well-done. Thus, the objective of this experiment was to determine the effect of an interaction between degree of doneness and Warner-Bratzler shear force (an objective measure of tenderness) on tenderness classification. Results indicate degree of doneness and tenderness interacted such that the decrease in tenderness as degree of doneness increased was greater for less tender than more tender ribeye steaks. The effect of this interaction on tenderness classification was to increase the advantage in shear force of a "Tender" class of beef over "Commodity" beef as degree of doneness increased. When aged 14 d and cooked well-done, "Commodity" steaks were six times more likely than "Tender" steaks to have unacceptably high shear force values (24 vs 4%). The beef industry could provide consumers with products that would be consistently tender, regardless of degree of doneness, by identifying and marketing "Tender" beef.
Technical Abstract: The objective of this experiment was to determine the effect of an interaction between end point temperature and Warner-Bratzler shear force on tenderness classification. Warner-Bratzler shear force was determined on longissimus thoracis cooked to either 60, 70, or 80 deg C after 3 and 14 d of aging from carcasses of 100 steers and heifers. Warner-Bratzler shear force values for steaks cooked to 70 deg C were used to create five tenderness classes. The interaction of tenderness class and end point temperature was significant (P < .05). The increase in Warner-Bratzler shear force as end point temperature increased was greater (P < .05) for less tender longissimus than more tender longissimus (Tenderness class 5 = 5.1, 7.2, and 8.5 kg and Tenderness class 1 = 2.4, 3.1, and 3.7 kg, respectively, for 60, 70, and 80 deg C). One effect of the interaction of tenderness with end point temperature on tenderness classification was to increase (P < .01) the advantage in shear force of a "Tender" class of beef over "Commodity" beef as end point temperature increased (.24 vs .42 vs .60 kg at 14 d for 60, 70, and 80 deg C, respectively). When aged 14 d and cooked to 80 deg C, "Commodity" steaks were six times more likely (P < .01) than "Tender" steaks to have shear force values > 5 kg (24 vs 4%). Another effect of the interaction was that a few (4%) of the "Tender" steaks had shear force values > 5 kg if cooked to 80 deg C. However, this latter effect could be adjusted for during classification. The beef industry could alleviate the detrimental effects on palatability of consumers cooking beef to elevated degrees of doneness by identifying and marketing "Tender" longissimus.