Abstract: This experiment was conducted to research into the influence of different treatments on beef Warner-Bratzler shear force and myofibrillar fragmentation index (MFI). Three crossbred yellow cattle (Luxin× Limusin) were slaughted according to standard slaughting practices. After being chilled for 20h, samples were made from carcasses and were injected (10% of weight) with distilled water(as control) or with 200 Calcium chloride, 200mmol/L EGTA, 200mmol/L Znic chloride, 0.2mg/ml Leupeptin, 0.2mg/ml Leupeptin plus 1% Triton X-100, and 1% Triton X-100 respectively. The result indicated that exogenous calpains inhibitors, Leuptptin and Znic chloride have slowed beef aging process significantly, and made beef with higher Warner-Bratzler shear force (WBS) and lower Myofibrillar fragmentation index. On the contrary, however, calcium chloride injection greatly shortened beef aging period, and the shear force value of beef injected with calciun chloride and aged for 4 d was not significantly different with that of control aged for 16 d.

Key words: beef, injection-treatment, Warner-Bratzler shear force, myofibrillar fragmentation index