Meat color by numbers: Evaluation of the myoglobin redox forms by different methods and its relationship to CIE color indices

Abstract

This study aimed to assess two methodologies (K/S and Krzywicki methods) based on reflectance measurements for estimating the myoglobin (Mb) meat redox forms (deoxymyoglobin, DMb; oxymyoglobin, OMb; and metmyoglobin, MMb), determining their relationship with the CIE color. Different Mb redox reference values were evaluated, and their proportions were estimated in beef longissimus muscle during blooming and display storage. The better reference standards for use in the K/S method were defined as surface reading immediately after meat cutting for 100 % DMb and reading one day after oxidation with potassium ferricyanide for 100 % MMb. Despite being highly correlated (r > 0.92), the K/S and Krzywicki methods produced different pigment proportions. The OMb and MMb obtained by the K/S method were much more consistent with the expected proportion of these pigments during the blooming and oxidation processes. The yellowness (b*) and hue (h) values best described the changes during blooming and were related with OMb formation, while redness (a*) and chroma (C*) were related to the changes in beef discoloration associated with MMb accumulation. This research highlights the importance of analyzing both pigment proportions and colorimetric data in meats, providing unique perspectives on the slight yet crucial changes in meat color.