The effect of electrical stimulation on post mortem myofibrillar protein degradation and small heat shock protein kinetics in bull beef

This study aimed to determine the effect of electrical stimulation and ultimate pH (pH(u)) on shear force, myofibrillar protein degradation and small heat shock protein (sHSP) concentrations in M. longissimus lumborum (LL). The LL from both sides of carcasses (n = 15) was excised with low voltage electrical stimulation (ES) applied to an LL muscle from one side, while the opposing LL muscle was not stimulated (NS). Muscles were categorised into low (PHu<5.8), intermediate (5.8 <= pH(u) <6.2) and high pH(u) (pH(u) >= 62) and aged for up to 28 days post mortem at -1.5 degrees C. High pliu meat tenderised faster which corresponded with the faster degradation of titin and desmin in this group compared with low and intermediate pH(u) meat. Electrical stimulation significantly affected the variable levels of alpha beta-clystallin and HSP20 with higher concentrations of these sHSP in ES muscles at later ageing timepoints compared with NS muscles. (C) 2015 Elsevier Ltd. All rights reserved.