Relationship of Fiber Type Composition to Marbling and Tenderness of Bovine Muscle

ABSTRACT Beef carcasses (n = 65) were selected to range widely in marbling (moderately abundan: to practically devoid) and maturity (A, n = 25; B, n = 19; C, n = 6; D, n = 8; E, n = 7). Number, percent, area and mean diameter of β‐red (βR), α‐white (αW) and α‐red (αR) muscle fibers were determined. Warner‐Bratzler shear force values and taste panel tenderness ratings were also obtained. αW muscle fiber parameters were negatively correlated (P < 0.05) to marbling and tenderness ratings while αR and βR parameters were positively correlated (P < 0.05) to these quality attributes. The ratio of αW fiber area to βR and/or αR fiber area was correlated (P < 0.05) with marbling and tenderness. Regression analyses indicate that muscle fiber type composition is more highly related to marbling (marb) than it is to shear force value (SFV) or tenderness rating (TR) although all relationships were significant (P < 0.10). The relationship of these quality indicators to fiber type is greater within A maturity [marb, coefficient of determination (C.D.) = 65.09; SFV, C.D. = 65.09; SFV, C.D. = 28.85; TR, C.D. = 62.94] than for the entire population (murb, C.D. = 49.16; SFV, C.D. = 18.71; TR, C.D. = 30.47). It appears that the oxidative capacity of a muscle is related to marbling and tenderness and that muscle fiber type composition could possibly be used as a predictor of marbling potential.