Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 21, 1998
Publication Date: N/A
Interpretive Summary: It has been shown that beef production in the U.S. results 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 and juiciness decrease 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 impact of USDA quality grade (Low Select vs Top Choice) on the palatability of "tender" ribeye steaks when cooked well done. Results indicate Top Choice steaks were more juicy and had more beef flavor than Low Select steaks. Top Choice steaks were more tender than Low Select steaks when aged only three days. However, after fourteen days of aging, there was no difference in tenderness between Top Choice and Low Select steaks. Compared to steaks from Low Select carcasses, the palatability of steaks from Top Choice carcasses was less affected by higher degree of doneness in "tender" ribeye steaks, especially when steaks were aged for only three days. The beef industry could provide consumers with products that would be consistently tender by identifying and marketing "Tender" beef. In order to ensure desirable beef eating quality to consumers who cook beef well done, tenderness classification of beef may need to be implemented in conjunction with the use of USDA quality grade.
Technical Abstract: The objective of this experiment was to determine the impact of USDA quality grade on the palatability of "tender" longissimus when cooked well done. Warner-Bratzler shear force was determined on longissimus thoracis steaks aged 3 and 14 d postmortem (cooked to 70 deg C) from carcasses of 692 steers and heifers. Steaks from 31 carcasses with Modest or Moderate marbling scores (Top Choice) and steaks from 31 carcasses with Slight 00 to Slight 40 marbling scores (Low Select) were selected for this experiment from those carcasses identified as "tender" (shear force < 5.0 kg at 3 d postmortem). Longissimus thoracis steaks with 3 and 14 d postmortem aging were cooked to 80 deg C and evaluated by a trained sensory panel. Quality grade was not related (P > .05) to tenderness rating (6.6 vs 6.3), but Top Choice steaks had higher (P < .05) juiciness (5.8 vs 5.3) and beef flavor intensity ratings (4.9 vs 4.6) than Low Select steaks. Aging of steaks for 14, as compared to 3, days postmortem improved (P < .05) tenderness rating (6.9 vs 6.0) and beef flavor intensity rating (4.8 vs 4.7), but not (P > .05) juiciness rating (5.6 vs 5.5). The interaction (P < .05) of quality grade and aging time for tenderness rating indicated that Top Choice steaks were more tender (P < .05) with 3 d aging than steaks from Low Select carcasses (6.3 vs 5.8), but steaks of Top Choice and Low Select carcasses had similar (P > .05) tenderness ratings after 14 d aging (7.0 and 6.8). Compared to steaks from Low Select carcasses, the palatability of steaks from Top Choice carcasses was less affected by elevated degree of doneness in "tender" longissimus thoracis, especially when steaks were aged for only three days.