Effect of low voltage electrical stimulation on protein and quality changes in bovine muscles during postmortem aging

• Low voltage electrical stimulation (ES) was applied to one side of beef carcasses.
• Four muscles (longissimus, semimembranosus, adductor, and gracilis) were evaluated.
• ES resulted in a more rapid pH decline during 24 h of postmortem period.
• ES did not influence proteolysis and tenderness of the beef muscles.
• Aging for 9 d improved tenderness and the extent of troponin-T degradation.

This experiment was conducted to determine the influence of low voltage electrical stimulation (ES) on the tenderness development of beef round muscles. Eight steers were slaughtered, and ES applied to one side of each carcass within 90 min of exsanguination. Steaks from M. longissimus dorsi, semimembranosus, adductor, and gracilis were vacuum packaged and aged at 4 °C for 9 d. Star probe, sensory evaluation, Western blot assays of troponin-T and μ-calpain autolysis and 2D-DIGE were conducted. ES resulted in accelerated (P < 0.05) pH decline of the longissimus in the first 24 h postmortem. ES did not influence (P > 0.05) proteolysis and tenderness, but did alter the predominance of metabolic proteins in the soluble fraction of muscle. Aging for 9 d improved tenderness (P < 0.05). The data confirmed that low voltage ES at 90 min of exsanguination had no effect on proteolysis and tenderness development in the longissimus dorsi, semimembranosus, adductor or gracilis in beef.