High glycolytic potential does not predict low ultimate pH in pork

• Published in: Meat science 2013-09, Vol.95 (1), p.85-91
• Main Authors: Scheffler, T.L., Scheffler, J.M., Kasten, S.C., Sosnicki, A.A., Gerrard, D.E.
• Format: Article
• Language: English
• Subjects: AMP-activated protein kinase; AMP-Activated Protein Kinases - metabolism; Animals; Female; Genotype; Glucose - chemistry; Glucose-6-Phosphate - chemistry; Glycogen; Glycogen - chemistry; Glycolysis; Hydrogen-Ion Concentration; Lactate; Lactic Acid - chemistry; Male; Meat - analysis; Muscle, Skeletal - chemistry; Pork quality; Swine
• ISSN: 0309-1740; 1873-4138
• DOI: 10.1016/j.meatsci.2013.04.013

Extent of postmortem pH decline influences meat quality development. To better understand physiological determination of ultimate pH (pHu), we utilized female and castrated male pigs from a line whose selection index includes differentiated pHu. All genotypes of AMP-activated protein kinase γ3 subunit (AMPKγ3) V199I site were present. The mutant 199II genotype increased pHu, but only in castrated males. Genotype affected glycolytic potential (GP), but GP was weakly associated with pHu. A subset of animals was selected based on low (−Gly) and high (+Gly) residual glycogen content, and compared with AMPKγ3 200Q, which is associated with low pHu. Both +Gly and 200Q muscle contained glycolytic substrate at 24h; however, 200Q muscle generated low pHu and greater lactate compared to +Gly. Additionally,−Gly and +Gly groups exhibited similar pHu despite a large difference in GP. In conclusion, high GP does not appear to directly impact the extent of postmortem pH decline. •Glycogen content in porcine muscle is highly variable.•Mutations in AMP-activated protein kinase γ3 affect muscle glycogen content.•AMPKγ3 199I may reduce capacity of muscle to store glycogen.•The RN− or AMPKγ3 200Q mutation is closely associated with low ultimate pH.•Muscle glycogen content does not directly cause low ultimate pH.