CIELAB color coordinates versus relative proportions of myoglobin redox forms in the description of fresh meat appearance.

This work examined changes in color that can be explained solely on the basis of the total myoglobin content and the relative proportions of deoxymyoglobin, oxymyoglobin (OMb) and metmyoglobin (MMb) during storage of meat. Meat color was evaluated for L*, a*, b*, C* and hab. Total pigment content was measured from the reflex attenuance at 525 nm (A525). The relative proportions of each pigment was determined using two different methods: the Krzywicki method based on the reflex attenuance values at 473, 525, 572 and 700 nm and the KS method based on K/S ratios of the absorption and scattering coefficients (K/S)474 ÷ (K/S)525, (K/S)572 ÷ (K/S)525 and (K/S)610 ÷ (K/S)525. The study was performed on beef (Longissimus lumborum) samples measured after 1, 4 and 7 days of exposure to air. Result revealed that L* values can be fully explained by A525 alone. C* and a* were well explained by those parameters related to OMb content. The other color parameters depended on pigment forms. The KS method gave better results. The parameters related to MMb content were relevant to classify samples according to the time of exposure to air. In any case, information provided by color and pigment parameters were complementary to each other.