The relationship of pork longissimus muscle pH to mitochondrial respiratory activities, meat quality and muscle structure

The way the pH falls post-slaughter has an impact on meat quality. Pork longissimus muscles (n = 48) were sorted in fast-(FG) (n = 15) and normal glycolysing (NG) (n = 33) muscles according to the post-slaughter pH 45 min values (FG < 6.0; NG > 6.0). FG muscles (5.84 +/- 0.04) compared with NG muscles (6.27 +/- 0.04) were accompanied with higher temperature, electrical conductivity, lightness and yellowness, and reduced grill loss and shear force values (P < 0.05), but there were no pH-dependent changes of the drip loss and redness results. FG muscles had higher (P < 0.05) percentages of fast-twitch glycolytic and lower proportions of fast-twitch oxidative and slow-twitch oxidative (P < 0.05) muscle fibres. The study confirms the relationship of pH value to meat quality and muscle fibre characteristics also showing that pH values have no impact on intrinsic mitochondrial respiratory function.