EFFECTS OF COOKING AND SHEARING METHODOLOGY ON VARIATION IN WARNER-BRATZLER SHEAR FORCE VALUES IN BEEF

Longissimus lumborum between the 13th rib and the 4th lumbar vertebra from 57 steers was obtained at 48 h postmortem, stored at 2 degrees C, and frozen after 7 d postmortem. Consecutive 2.54-cm-thick, paired steaks were used td make the following comparisons: Protocol A) steaks were broiled to 70 degrees C, chilled 24 h at 3 degrees C, cored parallel to fiber orientation, and sheared with a Warner-Bratzler attachment to the Instron and Protocol B) steaks' were modified-oven-broiled to 65 degrees C, cooled 30 min at 23 degrees C, cored perpendicular to the steak surface, and sheared with a Warner-Bratzler shear machine. Each of the four differences in protocol was subsequently compared one at a time with paired steaks. Protocol A resulted in higher (P < .05) shear force values than Protocol B (6.29 vs 3.60 kg). Neither shearing instrument nor cooling condition contributed to the difference (P > .05) in shear values. However, parallel vs perpendicular core orientation (6.31 vs 4.51 kg, respectively) and broil to 70 degrees C vs modified-oven broil to 65 degrees C cooking method (6.37 vs 5.31 kg, respectively) increased(P < .05) shear force values. Total variance (6.2 vs 1.2 kg(2)) and the proportion of variance in shear value attributed among animals was greater (P < .05) for Protocol A than for Protocol, B (70.0 vs 44.5%). These data indicate that Protocol A resulted in greater animal differences in shear values, and thus was more discriminating than Protocol B. In addition, variation in shear force within an animal could be reduced by increasing the number of cores, but not by increasing the number of steaks.