The effects of marbling level, electrical stimulation, and postmortem aging on the cooking and palatability properties of beef rib-eye steaks

Abstract

A total of 458 beef rib-eye steaks (longis-simus thoracis) from 229 carcass left sides were used to evaluate the effects of degree of marbling, electrical stimulation, and postmortem aging on the cooking and palatability properties of beef. One steak from each side was randomly allocated to 4 or 11 d of postmortem aging. Steaks were roasted to an internal temperature of 70 °C in a conventional oven preheated to 177 °C, and six cubes of lean from each steak were randomly assigned to a trained panel for palatability evaluation. Degree of marbling had no effect on initial or overall tenderness, flavour intensity, or desirability, but steaks with slight or greater marbling levels were juicier (P < 0.05) than those with traces of marbling. The percentage of unacceptable ratings for steaks, based on overall palatability, declined from 38.5% for traces of marbling to 23.7% for modest marbling levels. Low-voltage electrical stimulation had no effect (P < 0.05) on any of the palatability traits. Postmortem aging significantly (P < 0.05) increased the tenderness and overall palatability of rib-eye steaks while decreasing the frequency of unacceptable ratings of steaks from 38.8% in 4-d-old steaks compared with 24.0% in 11-d-old steaks. The results of this study confirmed the importance of postmortem aging to beef tenderness and palatability and the importance of marbling level to juiciness, but indicated that low-voltage stimulation was ineffective in improving beef palatability. Key words: Beef, carcass, palatability, marbling, electrical stimulation, aging