title: Post-mortem changes in porcine M. longissimus studied by solid-state 13C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy.
abstract: Solid-state (13)C cross-polarization (CP) magic-angle spinning (MAS) nuclear magnetic resonance (NMR) experiments are carried out for the first time on rapidly frozen muscle biopsies taken in M. longissimus in vivo and at 1 min, 45 min, and 24 h post-mortem from three pigs. Two of the pigs were CO(2)-stunned (control animals), and one was pre-slaughter-stressed (treadmill exercise) followed by electrical stunning to induce difference in metabolism post-mortem. (13)C resonance signals from saturated and unsaturated carbons in fatty acids, carboxylic carbons, and carbons in lactate and glycogen are identified in the solid-state NMR spectra. The (13)C CP MAS spectra obtained for post-mortem samples of the stressed, electrically stunned pig differ significantly from the post-mortem control samples, as the intensity of a resonance line appearing at 30 ppm, assigned to carbons of the methylene chains, is reduced for the stressed pig. This spectral difference is probably due to changes in lipid mobility and indicates altered membrane properties in the muscle of the stressed/electrically stunned animal when compared with the control animals already 1 min post-mortem. In addition, the post-mortem period changes in glycogen carbons can be estimated from the (13)C CP MAS spectra, yielding a correlation of r = 0.74 to subsequent biochemical determination of the glycogen content.
authors.affiliation: Department of Animal Product Quality, Danish Institute of Agricultural Sciences, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark. HanneC.Bertram@agrsci.dk
authors.forename: Hanne Christine
authors.initials: HC
authors.lastname: Bertram
authors.forename: Hans Jørgen
authors.initials: HJ
authors.lastname: Jakobsen
authors.forename: Henrik Jørgen
authors.initials: HJ
authors.lastname: Andersen
authors.forename: Anders Hans
authors.initials: AH
authors.lastname: Karlsson
authors.forename: Søren Balling
authors.initials: SB
authors.lastname: Engelsen
mesh_terms: D000818:Animals; D002247:Carbon Isotopes; D015925:Cryopreservation; D005227:Fatty Acids / Q000032:analysis; D006003:Glycogen / Q000032:analysis; D019344:Lactic Acid / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry*; D011180:Postmortem Changes; D013552:Swine
chemical_list: D002247:Carbon Isotopes; D005227:Fatty Acids; D019344:Lactic Acid; D006003:Glycogen