Bison meat is darker than beef, and color stability is a limitation to the expansion of fresh meat marketing. Although traditional dark cutting (high ultimate pH arising from prolonged pre-slaughter stress) may occur in bison, bison do have an inherently darker meat color due to differences in muscle fiber type and resulting greater pigment content. Bison meat color is also consistently unstable (early browning) under retail aerobic packaging conditions. The rapid pigment oxidation and surface discoloration mechanisms are not well understood.
In a comparative study characterizing the myoglobin protein between bison and beef, Joseph et al. determined that bison and beef had 100% amino acid sequence similarity and exhibited similar oxidation kinetics and thermostability; consequently, the rapid discoloration in bison meat could not be attributed to biochemistry of bison myoglobin. Variations in the balance between antioxidant–prooxidant components in the sarcoplasm could induce lipid oxidation and cause meat discoloration.
In addition, the greater PUFA content in bison could be susceptible to oxidation and generate reactive secondary oxidation products such as 4-hydroxy-2-nonenal (HNE), which accelerates myoglobin oxidation and subsequent meat discoloration. However, the role of HNE on bison color has not been evaluated yet.
