| Three experiments were conducted to evaluate and model cooking parameters to optimize tenderness of beef biceps femoris (BF) and longissimus lumborum (LL) muscles. In experiment #1, the effects of cooking method, holding temperature, holding time, and reheating on Warner-Bratzler peak shear force (WBPSF), myofibrillar force (WBM-F), connective tissue force (WBC-F), and cooking loss were investigated. Subprimals from USDA Choice beef carcasses were processed into steaks that were cooked by either a belt grill or a water bath. Water-bath cooking resulted in higher WBPSF, WBM-F, and WBC-F than belt-grill cooking for LL. Cooking BF steaks to 54°C by a belt grill and holding them at 57°C in a water bath for 15 min and subsequent reheating to 70°C reduced WBPSF, WBC-F and WBM-F by 37, 25, and 12%, respectively, compared to heating directly to 70°C. Water-bath cooking resulted in lower WBPSF than belt-grill cooking for BF. Cooking losses were higher with water-bath cooking for both muscles. In experiment #2, BF and LL steaks were cooked from either a frozen or thawed state on a belt grill. Cooking loss, cooking time, Warner-Bratzler shear force (WBSF), and color (Illuminant A, L*, a*, b*) were evaluated. Trained panelists evaluated palatability attributes on an 8-point scale for myofibrillar tenderness, juiciness, flavor, overall tenderness, and connective tissue amount. L*, a*, WBSF, juiciness, flavor, connective tissue amount, and overall tenderness did not differ (P > 0.05) between steaks cooked from frozen and thawed states. L*, a*, or b* values did not differ (P > 0.05) between muscles. In experiment #3, each BF and LL steak was cooked individually in a forced-air convection oven at 163°C to 70°C. A mathematical model based on solving two-dimensional, unsteady-state heat and mass transfer problem with the finite difference method was used to predict cooking time and temperature profiles. There was no difference (P > 0.05) between experimental and modeled cooking times for either LL or BF steaks. A highly positive linear relationship was found between experimental and modeled temperature profiles for both LL (R2 = 0.99) and BF (R2 = 0.96). Cooking parameters can be mathematically modeled to optimize tenderness and to predict cooking time and temperature profiles. |
