EFFECT OF HYDRODYNAMIC PRESSURE PROCESSING AND AGING ON SARCOPLASMIC PROTEINS OF BEEF STRIP LOINS

This study evaluated the effects of hydrodynamic pressure processing (HDP) and aging on the sarcoplasmic proteins of beef strip loins. Loins (n = 12) were halved at 48 h postmortem and assigned to HDP or control treatments. Following treatment, each half was divided into three portions for aging (0, 5 or 8 d). Samples were removed for Warner-Bratzler shear force (WBSF) determination and sarcoplasmic protein isolation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated that aging significantly influenced the composition of the sarcoplasmic protein fraction and that HDP influenced protein bands corresponding to 143, 65, 44, 36 and 19 kDa. Changes in sarcoplasmic protein composition were significantly correlated to WBSF (r = −0.58 to 0.45). Sarcoplasmic protein solubility decreased with both HDP (P < 0.05) and aging (P < 0.0001). Changes in solubility were significantly correlated to SDS-PAGE band intensities (r = −0.53 to 0.60). Data suggest that HDP and aging cause changes to sarcoplasmic proteins that may be indicators of proteolysis and tenderization. PRACTICAL APLICATIONS Results from this study demonstrate that postmortem aging and hydrodynamic pressure processing of beef influences the sarcoplasmic protein profile of the muscle. The relationships between these changes and Warner-Bratzler shear force measurements suggest that sarcoplasmic protein changes may be potentially useful as tenderness indicators.