Consumers rely heavily on fresh meat color as an indicator of wholesomeness at the point of sale, whereas cooked color is exploited as an indicator of doneness at the point of consumption. Deviations from the bright cherry-red color of fresh meat lead to product rejection and revenue loss. Myoglobin is the sarcoplasmic heme protein primarily responsible for the meat color, and the chemistry of myoglobin is species specific. The mechanistic interactions between myoglobin and multiple extrinsic and intrinsic factors govern the color of raw as well as cooked meats. The objective of this review is to provide an overview of the current research in meat color and how the findings are applied in the meat industry. Characterizing the fundamental basis of myoglobin's interactions with biomolecules in postmortem skeletal muscles is necessary to interpret the chemistry of meat color phenomena and to engineer innovative processing strategies to minimize meat discoloration-induced revenue loss to the agricultural economy.

The objective of the present study was to differentiate the sarcoplasmic proteome of color-stable (Longissimus lumborum; LL) and color-labile (Psoas major; PM) beef muscles. LL and PM muscles from seven beef carcasses (24 h post-mortem) were fabricated into 2.54 cm steaks, aerobically packaged, and assigned to refrigerated retail display for 9 days. LL steaks demonstrated greater (P < 0.05) color stability and lower (P < 0.05) lipid oxidation than PM steaks. Proteome analyses identified 16 differentially abundant proteins in LL and PM, including antioxidant proteins and chaperones. Proteins demonstrating positive correlation with redness (aldose reductase, creatine kinase, and β-enolase) and color stability (peroxiredoxin-2, peptide methionine sulfoxide reductase, and heat shock protein-27 kDa) were overabundant in LL, whereas the protein overabundant in PM (mitochondrial aconitase) exhibited negative correlation with redness. The color stability of LL could be attributed to the overabundance of antioxidant proteins and chaperones, and this finding suggests the necessity of developing muscle-specific processing strategies to improve beef color.

No abstract

No abstract

This manuscript overviews the pertinent research on internal color of uncured cooked meats, biochemical processes involved in meat cookery, and fundamental mechanisms governing myoglobin thermal stability. Heat-induced denaturation of myoglobin, responsible for the characteristic dull-brown color of cooked meats, is influenced by a multitude of endogenous (i.e., pH, muscle source, species, redox state) and exogenous (i.e., packaging, ingredients, storage) factors. The interactions between these factors critically influence the internal cooked color and can confuse the consumers, who often perceive cooked color to be a reliable indicator for doneness and safety. While certain phenomena in cooked meat color are cosmetic in nature, others can mislead consumers and result in foodborne illnesses. Research in meat color suggests that processing technologies and cooking practices in industry as well as households influence the internal cooked color. Additionally, the guidelines of many international public health and regulatory authorities recommend using meat thermometers to determine safe cooking endpoint temperature and to ensure product safety.