Excess glycogen does not resolve high ultimate pH of oxidative muscle

England, E. M.; Matarneh, Sulaiman K.; Oliver, Emily M.; Apaoblaza, Ariel; Scheffler, J. M.; Shi, Hao; Gerrard, D.E.

doi:10.1016/j.meatsci.2015.10.010

Cited by 90 publications

(67 citation statements)

References 45 publications

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“…Ryu and Kim (2005) reported that increased percentage of white (Type IIb) muscle fibers in pork longissimus muscle was associated with increased glycolytic rate, and increased L* values at 45 min and 24 h postmortem, and decreased a* values at 45 min postmortem. England et al (2016) reported greater myoglobin concentration in pork masseter muscle [predominately composed of slow (red) muscle fibers] than longissimus muscle, which has a greater proportion of fast (white) muscle fibers. Cross et al (2018) identified QTL for myoglobin concentration of pork longissimus on chromosome 14 that were associated with calcineurin regulation.…”

Section: Resultsmentioning

confidence: 96%

Characterizing the Ham Halo Condition: A Color Defect in Fresh Pork Biceps Femoris Muscle

King

Shackelford

Schnell

et al. 2018

Meat and Muscle Biology

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This experiment characterized a color defect called halo, involving pale tissue in the superficial portion of ham muscles, causing a two-toned appearance. Biceps femoris muscles (n = 200) were obtained from the ham-boning line of a large processor. Instrumental color attributes were determined on the medial (inside) and lateral (halo) surfaces of the muscle. Muscles were sliced (2.54-cm-thick) perpendicular to the long axis of the muscle. Slices were numbered from the proximal end of the muscle so that slice numbers represented anatomical location. Severity of the defect was greatest on the distal end of the muscle corresponding to slices 6 and 7 (9 locations). The halo and inside portions of slices 6 and 7 were separated for myoglobin concentration and muscle pH determination. The inside portion of muscle had lower (P < 0.001) L* (53.1 versus 63.4) and greater (P < 0.001) a* (23.2 versus 15.3) and b* (18.5 versus 15.4) values than the halo portion. Compared to the halo portion, the inside portion of the muscle had greater (P < 0.001) muscle pH (5.7 versus 5.5) and myoglobin concentration (1.97 versus 0.85 mg/g). Four minimally and 5 severely affected muscles were sampled in the halo and inside portions for muscle fiber typing. Fiber type distribution did not differ (P > 0.05) between locations within minimally affected muscles. In severely affected muscles, the inside portion had increased (P < 0.001) proportion of type I fibers, and concomitant decrease (P < 0.001) in type IIB fibers relative to the halo portion. These data indicate that the halo portion of the muscle is much lighter and less red in color, resulting from reduced myoglobin concentration in this portion of the muscle associated with a shift in muscle fiber type. These results should contribute to solutions to mitigate the ham halo color defect.

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Section: Resultsmentioning

confidence: 96%

Characterizing the Ham Halo Condition: A Color Defect in Fresh Pork Biceps Femoris Muscle

King

Shackelford

Schnell

et al. 2018

Meat and Muscle Biology

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“…Once formed, AMP is converted to IMP by AMP deaminase, which leads eventually to the depletion of the adenine nucleotide pool (Greaser, 1986). The loss of adenine nucleotides has previously been shown to mediate premature ter-385 mination of postmortem metabolism (England et al, 2016). Yet, adenine nucleotides were not depleted by 120 min, suggesting that adenine nucleotides were not limiting, at least during the first 120 min postmortem.…”

Section: Glycolytic Metabolites and Adenine Nucleotidesmentioning

confidence: 99%

“…We previously showed that PFK starts to lose activity near pH 5.9 and becomes completely inactive at pH 5.5, which halts glycolytic flux and pH decline (England et al, 2014). In some cases, however, the depletion of adenine nucleotides (ATP, ADP, and 45 AMP) arrest glycolysis while PFK presumably is still functioning (England et al, 2016). Thus, any one or a combination of the aforementioned mechanisms can lead to the cessation of postmortem metabolism.…”

Section: Introductionmentioning

confidence: 99%

“…The termination of postmortem metabolism in the presences of residual glycogen and glycolytic metabolites is a function of adenine nucleotides depletion or pH-495 mediated inactivation of PFK (Kastenschmidt et al, 1968;Greaser, 1986;England et al, 2014England et al, , 2016. To test whether adenine nucleotides disappearance is the reason for the cessation of postmortem metabolism in P. major muscle, we added 24 h P. major muscle to the in 500 vitro system with 3 mM ATP (pH 5.9).…”

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confidence: 99%

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Phosphofructokinase and mitochondria partially explain the high ultimate pH of broiler pectoralis major muscle

et al. 2018

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During postmortem metabolism, muscle pH gradually declines to reach an ultimate pH near 5.6 across most meat species. Yet, broiler pectoralis major (P. major) muscle generates meat with high ultimate pH (pH ∼ 5.9). For better understanding of the underlying mechanism responsible for this phenomenon, we evaluated the involvement of breast muscle chilling on the extent of postmortem metabolism. Broiler breast muscles were either subjected to chilling treatment (control) or left at room temperature (RT) for 120 min. P. major muscle from the RT treatment had lower ultimate pH, greater glycogen degradation and lactate accumulation. While these findings suggest that carcass chilling can contribute to the premature termination of postmortem metabolism, chilling did not fully explain the high ultimate pH of P. major muscle. Our results also revealed that glucose-6-phosphate (G6P) was very low at 24 h, and therefore we hypothesized that G6P was limiting. To test this hypothesis, muscle samples from P. major and porcine longissimus lumborum (LL) muscle were homogenized into a reaction buffer that mimics postmortem glycolysis with or without 0.5 mg/mL isolated mitochondria. While samples containing porcine LL muscle reached the normal level of ultimate pH, P. major muscle samples reached a value similar to that observed in vivo even in the presence of excess G6P, indicating that G6P was not limiting. Mitochondria enhanced the glycolytic flux and pH decline in systems containing muscle from both species. More importantly, however, was that in vitro system containing chicken with mitochondria reached pH value similar to that of samples containing LL muscle without mitochondria. To investigate further, phosphofructokinase (PFK) activity was compared in broiler P. major and porcine LL muscle at different pH values. PFK activity was lower in P. major muscle at pH 7, 6.5, and 6.2 than LL muscle. In conclusion, carcass chilling can partially contribute to the high ultimate pH of broiler P. major muscle, while low PFK activity and mitochondria content limit the flux through glycolysis.

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“…The later changes and indicators of meat quality depend on the level of glycogen and the speed of its decomposition in the process of the so-called anaerobic glycolysis (2,22). Glycogen content significantly determines the final pH of meat (5,6) and has a bearing on plenty of its indicators, such as hydration properties, shear force, colour, and cooling loss (4,11,23).…”

Section: Introductionmentioning

confidence: 99%

Influence of post-mortem muscle glycogen content on the quality of beef during aging

Onopiuk

Półtorak

Wierzbicka

2016

Journal of Veterinary Research

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Introduction: Glycolic changes which occur post-mortem have an impact on the physical and sensory features of beef, which in turn determine the successive processes and influence such beef quality traits as colour, tenderness, and cooling loss. The aim of this study was evaluation of the post-mortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic acid, as well as examination of their impact on technological and sensory quality of selected muscles from HolsteinFriesian × Limousin breed carcasses. Material and Methods: The study included three muscles of different metabolic qualities and sarcomere length: m. semitendinosus, m. longissimus dorsi, and m. psoas major, collected from nine bull carcasses aged 24 ±2 months. Results: Significant correlations were found between the volume of cooling loss on individual days of aging and the pH value of muscle tissue, lactic acid and glycogen content, as well as beef lightness. However, no significant dependency between the volume of glycogen and the intensity of red and yellow colours was detected. Conclusion: The colorimetric analysis of glycogen and lactic acid can be an effective tool in predicting the quality of beef.

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Excess glycogen does not resolve high ultimate pH of oxidative muscle

Cited by 90 publications

References 45 publications

Characterizing the Ham Halo Condition: A Color Defect in Fresh Pork Biceps Femoris Muscle

Characterizing the Ham Halo Condition: A Color Defect in Fresh Pork Biceps Femoris Muscle

Phosphofructokinase and mitochondria partially explain the high ultimate pH of broiler pectoralis major muscle

Influence of post-mortem muscle glycogen content on the quality of beef during aging

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