Relationships between mechanical tenderness measurements and trained sensory panel attributes of beef Longissimus lumborum muscle

Abstract

Beef cattle (n = 62) were slaughtered and two strip loins (IMPS #180) were removed 48 h post mortem. Loins were subsequently vacuum packaged, aged 14 d at 5°C and cut into 2.54 cm thick steaks. Within each animal, steaks were randomly assigned to one of seven treatments: Warner-Bratzler shear force (WB), Allo-Kramer shear force (AK), slice shear force (SS), 25% dual-cycle compression (25), 50% dual-cycle compression (50), 75% dual-cycle compression (75) or trained sensory evaluation of myofibrillar tenderness (MT), connective tissue amount (CT) and overall tenderness (OT) using 8-point scales (1 = extremely tough, abundant and extremely tough; 8 = extremely tender, none, extremely tender, respectively). Compression values were obtained perpendicular (perp) and parallel (par) to muscle fiber orientation. The OT and WB, OT and AK, and OT and SS were highly correlated (P < 0.01) (r = -0.70, -0.61, -0.61, respectively). Simple correlation coefficients between MT and either WB, AK and SS were -0.70, -0.59 and -0.59, respectively (P < 0.01) and between CT and WB, AK and SS were -0.66, -0.60 and -0.51, respectively (P < 0.01). Simple correlation coefficients between each compression test and WB, AK, SS, MT, CT and OT were low, regardless of cycle or orientation (P < 0.01). Regression equations were calculated with first and second cycle as independent variables to predict WB, AK, SS, MT, CT and OT, although R² < 0.20 (P < 0.01). Additional regression equations were calculated using WB, AK or SS in combination with compression measures or alone to predict MT, CT and OT. Regression equations with the highest predictability for the tenderness measurements were: MT = 7.99 + -0.92(50, perp) + 1.04(50, par) + 0.02(75, perp) + -0.43(WB)(R² = 0.55, RMSE = 0.45); CT = 8.29 + 1.36(25, perp, 1) + -4.37(25, perp) + -0.01(75, perp, 1) + -0.36(WB)(R² = 0.54, RMSE = 0.46); OT = 7.99 + -0.41(WB)(R² = 0.49, RMSE = 0.50). These data indicate that common mechanical measurements of beef tenderness are highly correlated to each other and to trained sensory measures.