Predict tenderness of cooked beef.

Scientists at Texas A&M University have developed two novel biomechanical compression techniques--involving the analysis of texture and strain--for predicting cooked beef tenderness. The texture analysis approach is based on how instrumental techniques that shear or apply compressive forces to viscoelastic biological materials can characterize the deformation rate and intrinsic heterogeneity of the material.

The researchers developed an objective instrumental technique that mimics a simplified model of a first-chew cycle in the human masticatory process. They calculated the stiffness and total energy dissipated and then correlated this information to descriptive attribute measurements.

The scientists found that stiffness and the total energy dissipated were highly correlated to overall beef tenderness. Based on these data, a model for predicting tenderness using total energy dissipated was developed. In a validation study, the investigators calculated the total energy dissipated and the initial and final stiffness of raw steak cubes with designated fiber orientations. They used the model and instrumental technique at 3% stress in a 4-minute cycle.

These values were correlated to overall sensory tenderness scores and Warner-Bratzler shear force (WBSF) values. Linear regression models, which predicted cooked sensory tenderness, showed that energy dissipated-parallel and initial stiffness-perpendicular measurements were effective predictors of sensory tenderness. The WBSF approach was less effective.

The strain technique evolved from research on elastography intended to predict beef and pork meat quality. An understanding of the basic rheological properties of beef samples was required to effectively interpret strain images from elastography. Research was conducted to understand the fundamental rheological properties of beef muscles. Changes in stress relaxation curves between 70% and 50% of the maximum stress differed as the meat became tougher. This accounted for about 40% of a variation in WBSF values.

Further information. R. Miller, Texas A&M University, Department of Animal Science, TAMU 2471, College Station, TX 77843; phone: [phone]; fax: [phone]; URL: www.tamu.edu.