Effect of Ultrasound and Calcium Chloride on the Ultrastructure and the Warner-Bratzler Shear Force Value of Beef Shank Muscle Fibers

Meat tenderness is a major factor in consumer satisfaction. Tenderness may be quantified by changes in muscle sarcomere length, roughness (ultrastructure) and shear force. The ultrastructure and the Warner-Bratzler shear force value of beef shank muscle fibers were experimentally measured in controlled applications of ultrasound and calcium chloride. Uncooked beef samples were treated with ultrasound at 40 kHz at different intensities for 6 min, and then immersed in a range of calcium chloride solutions for 24 h. Warner–Bratzler shear analysis and atomic force microscopy (AFM) data collection were performed for each sample. AFM height derived data (the sarcomere length and roughness values) and the Warner–Bratzler shear force values indicate optimum ranges of ultrasound intensity and calcium chloride concentration for meat tenderization. While the effect of low intensity ultrasound alone was not significant, calcium chloride treatment increased the sarcomere length and decreased shear force values. Furthermore, the combination of ultrasound and calcium chloride increased the sarcomere length significantly and simultaneously reduced the Warner–Bratzler shear force tolerance of the sample. These data suggested that low intensity and frequency ultrasound alongside Calcium Chloride immersion can promote the transmembrane transport of calcium ions via the calpain system to improve meat tenderness.