|King, David - Andy|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2009
Publication Date: 8/14/2009
Citation: King, D.A., Wheeler, T.L., Shackelford, S.D., Pfeiffer, K.D., Nickelson, R., Koohmaraie, M. 2009. Effect of Blade Tenderization, Aging Time, and Aging Temperature on Tenderness of Beef Longissimus Lumborum and Gluteus Medius. Journal of Animal Science. 87:2952-2960.
Interpretive Summary: Beef purveyors often use blade tenderization in combination with postmortem aging to ensure the tenderness of steaks offered in foodservice establishments. However, blade tenderization could potentially pose a food safety risk if the subprimal surface is contaminated with large numbers of pathogenic bacteria. Thus, purveyors seek a non-invasive alternative for ensuring tenderness of beef cuts. This study was conducted to determine whether a small increase in storage temperature (3.3 versus -0.5°C) during aging (12, 26, or 40 d) would increase the aging response enough to eliminate the need for blade tenderization in top loin and top sirloin steaks. Blade tenderization, increased aging time, and increased aging temperature all improved tenderness in both muscles. Increasing aging temperature improved the tenderization associated with postmortem aging in both muscles by increasing the degradation of key proteins. However, the effect of blade tenderization was greater than the effect of increased aging temperature. Increasing the time and temperature of postmortem aging reduced the percentage of tough top loin steaks substantially. Furthermore, extended aging at either temperature could possibly be a suitable replacement for blade tenderization in some product lines. However, despite the improved tenderization associated with aging at elevated temperatures, aging alone did not sufficiently eliminate the incidence of tough top sirloin steaks. Therefore, aging alone would not suitably replace blade tenderization.
Technical Abstract: Purveyors are concerned about the food safety risk of non-intact meat products and are seeking strategies to ensure adequate meat tenderness without blade tenderization. This study was conducted to determine the effects of blade tenderization and time and temperature of aging on beef longissimus lumborum (LL) and gluteus medius (GM) tenderness. Beef strip loins (n = 300) and top sirloin butts (n = 300) were assigned to storage at either -0.5 or 3.3°C for 12, 26, or 40 d. Cuts were either blade tenderized (BT) or not blade tenderized (NBT) before steak cutting. One 2.54 cm steak from each subprimal was used for slice shear force determination and Western blotting of desmin. Desmin degradation was lower (P < 0.05) in LL stored at -0.5°C than LL stored at 3.3°C (57 and 65%, respectively). Aging from 12 to 26 d increased (P < 0.05) proteolysis (50 to 65%) in LL. Regardless of aging time, BT lowered (P < 0.05) LL slice shear force values. Aging time did not affect (P > 0.05) slice shear force values of BT LL steaks (10.4, 9.9, and 9.4 kg for 12, 26, and 40 d aging, respectively), but reduced (P < 0.05) NBT steak slice shear force values (15.1, 13.8, and 12.3 kg for 12, 26, and 40 d aging, respectively). Higher temperature did not affect (P > 0.05) slice shear force values of BT LL steaks (10.2 and 9.6 kg for steaks aged at -0.5 and 3.3°C, respectively), but improved (P < 0.05) slice shear force of NBT LL steaks (15.1 and 12.4, respectively). Aging at 3.3°C increased (P < 0.05) proteolysis in GM steaks (43 and 54% for -0.5 and 3.3°C, respectively). Longer aging times increased (P < 0.05) proteolysis (40, 46, and 60 for 12, 26, and 40 d aging, respectively) in GM steaks. BT GM steaks had dramatically lower (P < 0.05) slice shear force values than NBT steaks (13.7 and 19.9 kg, respectively). Raising aging temperature from -0.5 to 3.3°C reduced (17.6 versus 16.0 kg; P < 0.05), and increasing aging time from 12 d to 40 d improved (17.9 versus 15.2 kg; P < 0.05) slice shear force values of GM steaks. Blade tenderization and increased aging time and temperature all improved tenderness of beef LL and GM steaks, though blade tenderization provided greater improvements than increased aging time and temperature. Longer aging could potentially be used to replace blade tenderization for LL steaks, but not in GM steaks.