3.1. Meat pH
The typical ultimate pH of post-mortem skeletal muscle in beef,
pork, and lamb is 5.5–5.8, whereas post-mortem pH of avian muscles
ranges from 5.7 to 6.0. In contrast, the pH of livemuscle is≈7.2. As muscle
is converted to meat, glycogen breaks down and lactic acid accumulates,
and this is reflected as a declined pH. The rate and extent of the pH
decline significantly influence Mb functionality and stability (Scopes,
1964; Lawrie, 1965). Mb is more stable at pH 7.4 than at pH 5.6
(Livingston & Brown, 1981; Gotoh & Shikama, 1974). Several previous
studies (Table 2) examined the relationship between meat pH,Mb thermal
stability, and cooked color in beef, lamb, pork and turkey. Most
studies report that Mb in meat at a pH 6.0) protects Mb against heat-induced denaturation
and increases the internal redness of cooked meats.