Determination of the myoglobin states in ground beef using non-invasive reflectance spectrometry and multivariate regression analysis

Implications of the variation in bloom properties of red meat: A review

This review aimed to examine the literature about blooming to determine any practical implications for meat colour and colour stability. Blooming is critical to surface colour in addition to pigment and achromatic factors and causes meat to become lighter (higher L*) and redder (higher a*) due to the formation of oxymyoglobin (OMb). Bloom depth of red meat varies in the range of about 1-12 mm due to a range of extrinsic factors notably oxygen partial pressure, temperature and time post slicing. A range of intrinsic factors also affect bloom acting via the oxygen consumption rate of mitochondria and metmyoglobin (MMb) reductase activity post mortem, such as post mortem age, muscle type, rigor temperature, ultimate pH (pHu), genotype and vitamin E status. These sources of variation have implications for measurement protocols and commercial applications for colour and colour stability. Development of a rapid method to measure bloom depth would enable assessment of bloom independently of surface colour.

CIELAB color paths during meat shelf life

Meat color evolution from freshly cut to beyond shelf life, up to 40% of metmyoglobin, has been theoretically modeled using the Kubelka-Munk theory and a set of measured reference reflectance spectra of deoxymyoglobin, oxymyoglobin and metmyoglobin. Color evolution depicts characteristic color paths in CIELAB color space. During oxidation the model explains the approximately constancy of L*, b* and h_ab, with variations typically hidden by sample dispersion, and the special significance of a* and C* in relation with metmyoglobin formation. CIELAB ΔE* color difference and the reflectance ratio R630/R580 are even better indicators of metmyoglobin changes during oxidation. The role of a*, C*, ΔE* and R630/R580 and their relationship during oxidation is a normal feature in the model with quantitative predictions in general agreement with literature. Results further emphasize the dangers of reporting color coordinates in different illuminants.