Comparison of Forage-Finished and Grain-Finished Beef Carcasses

Abstract

Thirty pairs of carcasses (one forage-finished and one grain-finished of essentially identical USDA quality grade) were obtained. One side of each forage-finished carcass was chilled at conventional cooler temperatures; the other side was chilled at high cooler temperatures. High temperature chilling of forage-finished beef did not affect (P>.05) cooking loss, juiciness, flavor or overall palatability, but significantly decreased shear force requirements and nonsignificantly increased muscle fiber tenderness and amount of organoleptically-detectable connective tissue. Grain-finished beef was (P<.05) more tender, more desirable in flavor and more satisfactory in overall palatability than forage-finished beef. Grain-finished beef had twice as much subcutaneous fat as forage-finished beef, the longest sarcomeres and the lowest shear force values. Forage-finished beef had the least subcutaneous fat and when conventionally chilled had the shortest sarcomeres and the highest shear force values. Increases in fat thickness opposite the longissimus muscle (at the 12 to 13th rib interface) from 1.27 mm to 8.9 mm were associated with increased tenderness in a manner which suggests that fatter carcasses sustain less shortening of muscle fibers and/or increased enzymatic proteolysis during development of rigor mortis. Relationships between fatness, chilling rate and tenderness did not, however, account for all of the differences in tenderness between grain-finished and forage-finished beef. High temperature chilling of forage-finished beef improved tenderness, but did not make it comparable in tenderness or flavor to grain-finished beef.