RELATIONSHIP OF MYOFIBRIL FRAGMENTATION INDEX TO CERTAIN CHEMICAL, PHYSICAL AND SENSORY CHARACTERISTICS OF BOVINE LONGISSIMUS MUSCLE

Abstract

ABSTRACT Loin steaks from 78 carcasses of A, B, C and E maturities were categorized into three tenderness groups on the basis of sensory tenderness scores and Warner‐Bratzler (W‐B) shear force values. Myofibril fragmentation index (MFI), sarcomere length, total and soluble collagen, moisture, fat and pH values were determined for these steaks. Carcass characteristics were also measured. The physical, chemical and sensory values were statistically analyzed to determine the relationship of these values, especially the relationship and the importance of myofibril fragmentation to tenderness of loin steaks. Results of this study showed that myofibril fragmentation index (MFI) accounted for more than 50% of the variation in loin steak tenderness and that myofibril fragmentation was a more important effector of tenderness in loin steaks than collagen solubility or sarcomere length. The steaks used in this study varied widely in marbling degree and maturity; therefore, MFI should be an excellent predictor of broiled loin steak tenderness. Although a number of significant correlations were observed between MFI and carcass characteristics, none of these was of practical importance because they accounted for little of the variation in tenderness.