The Relationship of Some Intracellular Protein Characteristics to Beef Muscle Tenderness ^a, ^b

Abstract

SUMMARY A procedure developed to fractionate the major nitrogen‐containing components of muscle was utilized to study the relationship of intracellular muscle proteins to tenderness. The study was performed on a group of 20 yearling bulls from two lines of cattle that had been selected for differences in tenderness. The longissimus dorsi muscle contained more total nitrogen per unit of muscle tissue and almost twice as much sarcoplasmic protein as the infra‐spinatus muscle. The longissimus dorsi contained less fibrillar protein and non‐protein nitrogen than the infraspinatus. The following factors were correlated with tenderness as measured by shear and panel: sarcoplasmic protein nitrogen/total fibrillar protein nitrogen; soluble fibrillar protein nitrogen/ total fibrillar protein nitrogen; water released/total water. Fibrillar protein solubility was highly correlated with tenderness ( r. =−0.69 for shear and r = 0.59 for panel). An r value of 0.49, significant at the 5% level, was found between water‐holding capacity and tenderness as measured by the shear.