High glycolytic potential does not predict low ultimate pH in pork

Extent of postmortem pH decline influences meat quality development To better understand physiological determination of ultimate pH (pH(u)), we utilized female and castrated male pigs from a line whose selection index includes differentiated pH(u). All genotypes of AMP-activated protein kinase gamma 3 subunit (AMPK gamma 3) V199I site were present The mutant 199II genotype increased pH(u), but only in castrated males. Genotype affected glycolytic potential (GP), but GP was weakly associated with pH(u). A subset of animals was selected based on low (-Gly) and high (+Gly) residual glycogen content, and compared with AMPK gamma 3 200Q, which is associated with low pH(u). Both +Gly and 200Q muscle contained glycolytic substrate at 24 h; however, 200Q muscle generated low pH(u) and greater lactate compared to +Gly. Additionally, -Gly and +Gly groups exhibited similar pH(u) despite a large difference in GP. In conclusion, high GP does not appear to directly impact the extent of postmortem pH decline. (c) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.