Discoloration in fresh meat

The use of colorimetry for evaluating discoloration in fresh meat is well established and has been reviewed elsewhere (Francis and Clydesdale, 1975 Hunt, 1980). In general, a values are most commonly reported, as they indicate the degree of redness in meat. Several colorimetric parameters correlate very well with sensory assessment of meat discoloration and hue angle, as shown in Figure F3.3.3. 

Faustman, C. and Cassens, R.G. 1990. The biochemical basis for discoloration in fresh meat A review. J. Muscle Foods 1 217-243. 

In both pigments, the iron is in the ferrous form upon oxidation to the ferric state, the compound becomes metmyoglobin. The bright red color of fresh meat is due to the presence of oxymyoglobin discoloration to brown occurs in two stages, as follows ... 

The optimum pH for meat depends on the purpose for which it is intended. Fresh meat should be at the upper end of the normal pH range if it is to be preserved by freezing, since the reaction between myoglobin and unsaturated fat is inhibited in this range (see table V) and both discoloration and also fat oxidation are retarded. In addition, drip losses are minimized (Sair and Cook, 1938). 

Light accelerates all oxidative changes in meats, provided, of course, that oxygen is available. Discolorations caused by exposure to light have become a particularly serious problem because of modern methods of merchandising which require exposure of retail outs in lighted display oases. Cured meats are much more susceptible to light discoloration than fresh (Ramsbottom et al., 1951 Urbain and Ramsbottom, 1948). Appar-... 

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