The influence of myoglobin on the colour of minced pork loin

The influence of the total and chromatic absorbance at wavelengths of 525 nm (A525 and A525p) and 700 nm (A700), and the relative content of oxymyoglobin (MbO2), metmyoglobin (MetMb) and deoxymyoglobin (Mb), on the value of the colour parameters (L*, a*, b*, C* and h°) of minced pork loin, were evaluated. Lightness (L*) depended almost entirely on variation in total absorbance at a wavelength of 525 nm. Redness (a*) depended on the forms of myoglobin and A525p, while yellowness (b*) depended mainly on the proportions of the reduced form (Mb), the oxygenated form (MbO2) and the oxidised form (MetMb). Yellowness (b*) significantly increased with a decrease in the relative amount of Mb and an increase in relative amounts of MbO2 and MetMb, although a greater impact was exerted by fluctuations in MbO2 than MetMb. Variability of chroma (C*) depended mainly on proportions of the forms of myoglobin. Hue angle (h°) depended primarily on chromatic absorbance at 525 nm (A525p).