Effect of dietary ractopamine on tenderness and postmortem protein degradation of pork muscle

Y. L. Xiong, M. J. Gower, C. Li, C. A. Elmore, G. L. Cromwell, M. D. Lindemann

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Twenty-four finishing pigs with a mean starting weight of 82 kg were assigned to two dietary regimens: (1) a corn-soybean meal basal diet (control; n = 12), and (2) the basal diet supplemented with 20 ppm ractopamine HCl (RAC; n = 12). After 28-30 days on the feeding trial, pigs were slaughtered, and the growth and carcass characteristics were measured. Furthermore, the 3rd-13th rib section of longissimus muscle was excised at 48 h postmortem, sliced into 19-mm thick chops, vacuum packaged, stored at 2 °C, and subjected to Warner-Bratzler shear force (WBSF) and electrophoretic tests after 2, 4, 7, 10, 14, and 21 days (postmortem). RAC feeding increased (P < 0.01) pig carcass weight and percent lean, but it also increased the day-2 muscle WBSF by 20% (P < 0.01). The shear force difference between control and RAC pig muscles gradually decreased and vanished by day 10 (P > 0.05) when both muscle groups became more tender. The muscle from RAC-fed pigs exhibited a slower protein degradation rate than muscle from the control animals, notably for proteins in the 15-45 kDa range. The results suggested that the tenderness difference between ractopamine-treated and control pig muscles was related to the proteolysis rate, and could be diminished with adequate postmortem ageing.

Original languageEnglish
Pages (from-to)600-604
Number of pages5
JournalMeat Science
Issue number4
StatePublished - Aug 2006


  • Electrophoresis
  • Pork
  • Proteolysis
  • Ractopamine
  • Tenderness

ASJC Scopus subject areas

  • Food Science


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