The Influence of Cooking Temperature on the Eating Quality of Beef from Bulls and Steers Fed Three Levels of Dietary Roughage

Abstract

The cooking losses and subsequent eating quality of semimembranosus (SM) roasts obtained from bulls and steers fed three levels of dietary roughage (20, 50 and 80 percent alfalfa-brome hay) were determined. Evaluations were conducted by dry heat roasting at 121°C and 163°C to 63°C internal temperature. Cooking losses of SM roasts were affected by cooking temperature, but not by level of dietary roughage or castration. Subjective evaluation by a trained panel indicated that SM roasts cooked at 121°C were significantly better in texture, softness, juiciness, flavor, tenderness, residual connective tissue and overall acceptability than comparable samples cooked at 163°C. Objective measurements of juiciness (water holding capacity) and tenderness for SM roasts supported the findings from sensory evaluations. Trained panelists indicated that SM roasts from animals on all roughage levels were similar in eating quality. There were no significant differences in water holding capacity (WHC), Warner Bratzler shear and penetrometer data attributable to roughage levels; Ottawa Texture Measuring System (OTMS) data indicated that samples from the 20 percent roughage group were more tender than those from the 80 percent roughage group. SM roasts from steers were subjectively rated significantly better in texture, tenderness and connective tissue than comparable samples from bulls; roasts from both “sexes” were similar in all other quality characteristics evaluated. Roasts from bulls had a greater WHC than those of steers. There were no significant differences in Warner Bratzler shear force values and penetrometer data attributable to sex; OTMS data indicated that SM roasts from steers were more tender (P< 0.01) than comparable roasts from bulls. Thus, these studies provide evidence that: 1) dry heat roasting of a less tender cut at 121°C to 63°C resulted in a better product than that of comparable roasts cooked at 163°C; 2) beef obtained from animals fed varying levels of dietary roughage was similar and acceptable; and 3) beef from bulls may be less tender than from steers; however, beef from all animals was judged acceptable in eating quality.