Species-Specific Effects of Sarcoplasmic Extracts on Lipid Oxidationin vitro

Tandem Mass Tag Labeling-Based Analysis to Characterize Muscle-Specific Proteome Changes during Postmortem Aging of Bison Longissimus Lumborum and Psoas Major Muscles

The objective of the study was to examine the variations in sarcoplasmic proteomes of bison longissimus lumborum (LL) and psoas major (PM) muscles during postmortem aging utilizing tandem mass tag (TMT) isobaric labeling coupled with liquid chromatography mass-spectrometry (LC-MS/MS) for the categorization of muscles with muscle-specific inherent color stability. A total of 576 proteins were identified (P < 0.05) in both bison LL and PM muscles, where 97 proteins were identified as differentially abundant (fold change > 1.5, P < 0.05) from the three comparisons between muscles during postmortem aging periods (PM vs LL at 2 d, 7 d and 14 d). Among those proteins, the most important protein groups based on functions are related to electron transport chain (ETC) or oxidative phosphorylation, tricarboxylic acid cycle (TCA), ATP transport, carbohydrate metabolism, fatty acid oxidation, chaperones, oxygen transport, muscle contraction, calcium signaling, and protein synthesis. In PM, most of the proteins from ETC, TCA cycle, fatty acid oxidation, ATP and oxygen transport, and muscle contraction were more abundant or exhibited increased expression during aging compared to LL. On the other hand, the proteins involved in carbohydrate metabolism, chaperone function and protein synthesis mostly exhibited decreased expression in PM muscle relative to LL. These results clearly demonstrate that the proteins associated with oxidative metabolism showed increased expression in PM muscles. This indicates that oxidative damage or subsequent color deterioration resulted in bison PM muscles being attacked by the reactive oxygen species produced during those metabolic process. In contrast, proteins involved in glycolysis and chaperone activity exhibited a decrease in expression in bison PM muscles, resulting decline in color stability compared with LL. Because glycolytic enzymes and chaperones maintain oxidative and/or color stability by producing reducing equivalents in glycolytic pathway and with the protein folding ability of chaperones, respectively in LL muscles.

Exogenous and Endogenous Factors Influencing Color of Fresh Meat from Ungulates

Biochemistry of post-mortem muscle tissue is complex, and several factors affect the fresh meat color and color stability, both of which influence consumer acceptance. Therefore, improving meat color and meat color stability is of significant value to the meat industry and consumers. While extensive literature is available on the color and color stability of domestic ungulates, literature on wild ungulates is notably lacking. With an increasing global demand for meats from wild ungulates, it is critical to identify the knowledge gaps regarding their color and color stability. The objective of this paper is to overview the exogenous and endogenous factors influencing the color and color stability of fresh meats from domestic and wild ungulates. The literature highlighted that the pre- and post-harvest factors influencing meat color and meat color stability are interrelated and not mutually exclusive. Current research indicates that the effects of several of these factors are specific to species, breed, and muscle source. Novel ways to manipulate these factors using a biosystems approach should be explored to improve color attributes of fresh ungulate meats.

Characterization of bison (Bison bison) myoglobin

Bison is an alternate meat species gaining increased popularity in North America. Although previous investigations reported that bison meat discolors faster than beef, the molecular basis of this observation has not been investigated. Therefore, the objective of the present study was to determine the redox stability, thermostability, and primary structure of bison myoglobin (Mb), in comparison with beef Mb. Purified bison and beef myoglobins were analyzed for autoxidation, lipid oxidation-induced oxidation, and thermostability. Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry was utilized for determining the exact molecular mass of bison Mb, whereas Edman degradation was employed to determine the amino acid sequence. Bison and beef myoglobins behaved similarly in autoxidation, lipid oxidation-induced oxidation, and thermostability. The observed molecular mass of bison and beef myoglobins was 16,949 Da, and the primary structure of bison Mb shared 100% similarity with beef and yak myoglobins. Noticeably, the amino acid sequence of bison Mb was different from other ruminant myoglobins, such as water-buffalo, sheep, goat, and red-deer. The present study is the first to report the primary structure of bison Mb. Same primary structure and similar biochemical attributes of bison and beef myoglobins suggested that the observed rapid discoloration in bison meat could not be attributed to biochemistry of bison Mb.