Aged pork loins were selected to have similar ultimate pH, color, lipid content, and purge. The star probe values (kg) obtained from these loins were evaluated and loins were sorted into either a low star probe (LSP) group or a high star probe (HSP) group. Two-dimensional difference in gel electrophoresis (2D-DIGE) was used to identify differences insarcoplasmic proteomes between LSP and HSP groups. Metabolic, stress response, structural, and regulatory protein spots were identified to be significantly different between classification groups. The structural protein desmin was identified to be more abundant in LSP samples and the stress response protein peroxiredoxin-2 was identified to be more abundant in HSP samples. Because these protein were identified as being significantly different between classification groups in the soluble, sarcoplasmic fraction of samples, these proteins are potential candidates to be biomarkers to differentiate between tough and tender aged pork loins.