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 st eaks were used td make the following comparisons: Protocol A) steaks w ere broiled to 70 degrees C, chilled 24 h at 3 degrees C, cored parall el 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 th e steak surface, and sheared with a Warner-Bratzler shear machine. Eac h of the four differences in protocol was subsequently compared one at a time with paired steaks. Protocol A resulted in higher (P < .05) sh ear force values than Protocol B (6.29 vs 3.60 kg). Neither shearing i nstrument 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, respectiv ely) 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 t han Protocol B. In addition, variation in shear force within an animal could be reduced by increasing the number of cores, but not by increa sing the number of steaks.