Effect of electrical stimulation on quality-indicating, palatability and histological characteristics of beef

Vita.A three-part study was conducted to determine the effect of electrical stimulation on the quality, palatability and histological characteristics of beef. Experiment 1 determined the effects of using various numbers of electrical impulses on quality and palatability traits of lightweight beef carcasses. Experiment 2 determined the effects of combining electrical stimulation and postmortem aging to achieve optimum improvement in tenderness. Experiment 3 determined the effects of electrical stimulation on the structure of postmortem beef muscle. In Experiment 1, fifty light-weight heifers were slaughtered and randomly selected sides were electrically stimulated (machine setting=100 volts, 5 amps, 50-60 cycles per second; producing a 440 volt potential difference between electrodes) within 1 hr post-exsanguination. Treatment groups for paired sides included 0 vs 25, 0 vs 50, 0 vs 75, 25 vs 50, and 50 vs 75 electrical impulses per side. When significant differences in carcass traits, tenderness and overall palatability were observed between control and treated sides, advantages were always in favor of electrically stimulated sides. The most consistent improvements elicited by electrical stimulation were in USDA lean maturity score (more youthful), muscle color (brighter), incidence of "heat-ring" (less frequent; less severe), shear force (more tender) and sensory panel ratings (more tender; less organoleptically-detectable connective tissue; more desirable overall palatability) . Use of 75, rather than 25 or 50, impulses slightly reduced the incidence and severity of "heat-ring"; however, there was very little evidence that use of more than 25 impulses would materially enhance the response in palatability achieved via electrical stimulation.