Comparative studies on metabolic rate and calpain/calpastatin activity between Hanwoo and Holstein beef

The objectives of this study were to examine the effect of early short-term temperature conditioning on metabolic rate and calpain/calpastatin system and to compare variations in metabolic rate and calpain/calpastatin system between Hanwoo and Holstein beef. Longissimus thoracis et lumborum of the right carcass from 3 Hanwoo and 3 Holstein bulls were removed within 30 min of exsanguinations, cut into three pieces, and then temperature conditioned until 3 h postmortem (PM) at 2, 16, and 30°C, respectively. Rigor values (R-values; R₂₄₈, R₂₅₀, and R₂₅₈), pH, muscle temperature, glycogen content, μ- and m-calpain activities, and calpastatin acitivity were measured at 1, 3, 9, and 24 h PM, respectively. Hanwoo beef had higher muscle temperature, faster metabolic rate at early PM stage in R-values, and lower μ-calpain activity than Holstein beef (p<0.05). The 30°C treatment maintained muscle temperature of 30°C until 3 h PM and resulted in faster pH decline at 3 and 9 h PM (p<0.05) than other treatments. The 16°C had higher (p<0.05) muscle temperature at 3 h PM than the 2°C, but no difference in all other traits was observed between the 2°C and the 16°C. Early shortterm temperature treatment used in this study was not sufficient to effectively activate calpain/calpastatin system. Correlations among all traits except m-calpain and muscle temperature were generally high (r>0.60; p<0.001). Among R-values, R₂₅₈ had higher correlations with other metabolic traits than those of R₂₄₈ and R₂₅₀. These data suggest that early PM metabolic rate, μ-calpain activity, and calpastatin activity may be closely related to each other. Variations in metabolic rate and μ-calpain activity at early PM stage between Hanwoo and Holstein beef may imply variations in meat quality between both breeds.