title: Protein denaturing conditions in beef deep semimembranosus muscle results in limited μ-calpain activation and protein degradation.
abstract: The objective was to determine the effect of muscle location on protein solubility and protein degradation in deep (DSM) and superficial (SSM) portion of beef semimembranosus. At 24 h postmortem, the semimembranosus was removed from beef carcasses (n=10), packaged in high-oxygen modified atmosphere (80% O2+20% CO2), and displayed for 7 d at 1°C. DSM had higher (P<0.05) L*, a*, b*, and hue values than SSM throughout display. DSM had significantly higher protein denaturation and less protein concentration than SSM. Western blotting for μ-calpain autolysis revealed that DSM maintained more (P<0.05) unautolyzed μ-calpain than SSM. This result coincided with less desmin and troponin-T degradation in samples from the DSM. These results confirm the hypothesis that increased protein denaturation in DSM results in minimal proteolysis by negatively affecting μ-calpain activation. This demonstrates a potential to alter progression of proteolysis and improvement in tenderness associated with postmortem storage.
authors.affiliation: Meat Science & Muscle Biology Group, Department of Animal Science, Iowa State University, Ames, IA 50011, United States.
authors.forename: Yuan H
authors.initials: YH
authors.lastname: Kim
authors.forename: Steven M
authors.initials: SM
authors.lastname: Lonergan
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Huff-Lonergan
mesh_terms: D000818:Animals; D001272:Atmosphere; D015153:Blotting, Western; D002154:Calpain / Q000378:metabolism*; D002245:Carbon Dioxide; D002417:Cattle; D003116:Color; D018857:Food Packaging / Q000379:methods; D006868:Hydrolysis; D008460:Meat / Q000032:analysis*; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010100:Oxygen; D011180:Postmortem Changes; D011489:Protein Denaturation
chemical_list: D009124:Muscle Proteins; D002245:Carbon Dioxide; D002154:Calpain; D010100:Oxygen