Pork tenderness estimation by taste panel, Warner-Bratzler shear force andon-line methods

The extent to which modification of Warner-Bratzler shear force (WBSF) dete rminations, relating to storage and preparation of the meat, aperture of th e V-shaped cutting blade and shearing velocity, improve the relationship wi th sensory tenderness perception of pork was studied. Additionally four on- line methods: pH1, FOP1 (light scattering), PQM1 (conductivity) and DDLT (D ouble Density Light Transmission), were evaluated for their ability to pred ict tenderness. Sensory tenderness evaluation was conducted on 120 frozen ( at -18 degrees C for several months) samples of m. longissimus thoracis et lumborum. After overnight thawing, the meat was grilled to an internal temp erature of 74 degrees C and scored on an eight-point scale, from extremely tough to extremely tender. The standard WBSF procedure (protocol A) consist ed of heating fresh meat samples (stored for 48 h at 4 degrees C post slaug hter) at 75 degrees C for 50 min, cooling in cold tap water for 40 min, tak ing cylindrical cores parallel to the fibre direction, and shearing at a ve locity of 200 mm/min with a blade aperture of 60 degrees. For the predictio n of sensory tenderness, the WBSF standard procedure (protocol A) showed th e lowest variance (R-2 = 15%) and the highest standard error of the estimat e (SEE = 0.97 N) compared to the other WBSF protocols. A decrease in sheari ng velocity, from 200 to 100 mm/min and, a replacement of the cutting blade with an aperture of 60 degrees by one with an aperture of 30 degrees led t o improvements of R-2 (respectively, 19% vs. 13% and 47% vs. 23%) and SEE ( respectively, 0.93 N vs. 0.97 N and 0.80 N vs. 0.97 N) and thus were better predictors of tenderness. A blade aperture of 30 degrees instead of 60 deg rees also led to considerably lower WBSF values (22.1 N vs. 30.0 N). Freezi ng, frozen storage and thawing of the meat, prior to WBSF measurement, resu lted in higher shear force values (32.7 N vs. 28.7 N) and a better predicti on of tenderness, R-2 (25% vs. 15%) and SEE (0.94 N vs. 1.00 N). Furthermor e, preparing the frozen stored meat for WBSF determination in the same way as for the sensory evaluation, namely grilling instead of boiling, led to h igher WBSF values (35.5 N vs. 32.7 N) and a further improvement in the pred iction of tenderness (R-2 = 31% vs. 25% and SEE = 0.90 N vs. 0.94 N). From the on-line instruments: pH, FOP and PQM, pH was best in predicting tendern ess. Linear regression with tenderness as dependent variable and the on-lin e techniques as independent variables revealed the following R-2: 16, 8, 8 and 10% and SEE: 0.96, 1.01, 1.01 and 1.00 N for, respectively, pH1, FOP1, PQM1 and DDLT. Thus, the classical instruments and the DDLT technique, whic h is analogous to the CGM (Capteur Gras/Maigre), an officially accepted car cass grading apparatus in France and Belgium, are not good predictors of te nderness. (C) 1999 Elsevier Science Ltd. All rights reserved.