Submitted to: Journal of Texture Studies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 17, 1999
Publication Date: N/A
Interpretive Summary: Tenderness is the most important attribute of meat quality. Currently, tenderness is measured from cooked meat using the Warner-Bratzler (WB) shear tester, a standard device recommended by American Meat Science Association. This research was initiated to measure the fundamental shear properties of raw and cooked beef and to determine their relationship with WB tenderness measurement. We performed shear tests on four bovine muscles with three different aging treatments (0, 1, and 2 weeks). Results show that cooking resulted in significant changes in the shear properties of meat, and so did aging and muscle type. Meat tenderness was highly related to the shear properties (force, strain energy, etc.) of cooked meat with the R**2 being as high as 0.65. Lower or insignificant correlations were found between tenderness and shear properties of raw meat, which indicates the difficult to predict tenderness from raw meat. This research also found that WB testing was not effective in measuring tenderness for certain muscles. The findings of this research shall have some important implications in improving existing measurement methods and in developing an effective method to predict tenderness from raw meat.
Technical Abstract: Knowledge of mechanical properties of beef is essential in developing an effective method to predict tenderness and understanding the factors affecting tenderness measurement. The objectives of this research were to evaluate the shear properties of raw and cooked beef and determine how they are related to Warner-Bratzler (WB) tenderness measurement. Shear tests were performed, using a specially designed device, on four muscles, i.e., biceps femoris (BF), longissimus dorsi (LD), semimembranosus (SM), and semitendinosus (ST), with three different aging treatments (0, 1, and 2 weeks). Results showed that raw beef exhibited a nonlinear behavior characterized by linearity at small deformations, stress yield at intermediate deformations, and work hardening at large deformations. Cooked beef had a different nonlinear behavior with the slope of the force-displacement curve increasing with displacement before the peak force. Cooking resulted in a significant, large increase (p=0.01) in maximum shear force and strain energy. The effect of muscle type and aging on shear properties was mostly significant (p=0.05), but with less pronouncement. The maximum shear force of cooked beef was correlated with WB measurement with the R**2 value ranging from 0.65 to 0.34 for LD, SM, and BF except for ST with a R**2 value of 0.10. Correlations of the shear properties of raw meat with WB measurement were low (R**2 was less than 0.36), indicating the difficulty to predict WB tenderness from the shear properties of raw meat.