The influence of early post-mortem enhancement and the inclusion of dextrose in the brine solution were evaluated using crossbred market lambs (n = 41; average live weight = 46.16kg). Immediately post-harvest, carcasses were fabricated removing the leg and shoulder and then splitting the midsection (intact rack and loin) along the longitudinal axis of the spine. The left side was designated as the treatment side (pre- or post injection) with the right side being the paired control. Enhancement treatments were non-enhancement (control sides), standard solution (water, 2.0% salt and 0.5% tri-polyphosphate; STND) or (water, 2.0% salt, 0.5% tri-polyphosphate and 3% dextrose; DEXT). Loins designated to the pre-rigor treatment were injected with either STND or DEXT approximately 45 min post-mortem and those designated to the post-rigor treatment were injected approximately 24 h postmortem.
There was an interaction (P < 0.05) between time of injection and type of solution for pump yield, 24-h purge loss and 48-h yield. Pre-rigor enhanced midsections had greater (P < 0.05) pump yields than the post-rigor enhanced loins. Furthermore, midsections enhanced post-rigor with the STND solution had greater (P < 0.05) pump yields than those enhanced with the DEXT solution. The 24-h purge loss and 48-h yield followed the pattern of pump yield, in that greater pump yields also produced greater 24-h purge loss, but still resulted in greater 48-h yields.
After 48-h post harvest, the longissimus was removed from each midsection and sliced into eight, 2.54 cm thick chops, and a pair of chops were then randomly assigned to one of the four aging categories (2, 3, 4, and 7 day) to measure thaw loss, cook loss and slice shear force. In general, thaw loss followed pump yield with greater (P < 0.05) for pre- vs. post-rigor enhancement and greater thaw loss for chops from enhanced midsections vs. control sections. Additionally, there was a trend for thaw loss to increase with additional post-mortem aging. Cook loss was influenced (P < 0.05) by type of solution and followed the pump yield associated with the type of solution with pump yield and corresponding cook loss being STND>DEXT>control.
Post-mortem aging had a significant effect on slice shear force values with chops becoming more tender (P < 0.05) with additional aging. No differences (P > 0.05) were observed in tenderness due to timing of injection or type of enhancement solution. As enhancement resulted in increased salable yields without additional detrimental impacts, enhancement may and no detrimental were produced as a result of enhancement, this process may be a viable option for the lamb industry to improve economic viability while targeting increasing consumer demand and market share.