Biochemical studies on fast glycolysing bovine muscle

Of the psoas major muscles from 1395 carcasses of young bulls 64% showed pH(1) values (30 min post mortem) below 6·0. In 100 muscle samples (selected so that a normal distribution of the pH(1) values was obtained), water-holding capacity (WHC), brightness of colour and the concentration of all glycolytic metabolites were determined. There were correlations between pH(1) and the other characteristics of meat quality, lower pH(1) values were associated with lower WHC, paler colour, lower glycogen levels and higher levels of lactate (30 min post mortem). All these correlations were highly significant. The accelerated breakdown of glycogen-and a simultaneous accumulation of hexose monophosphates-indicate an activation of the phosphorylase system in fast glycolysing bovine muscle. In fast glycolysing muscle, creatine phosphate was almost absent by 1 h post mortem and the ATP level was very low, indicating a high rate of breakdown of high-energy phosphates. The quality deviation of fast glycolysing beef is much less severe than that of PSE pork and therefore might not present a serious economic problem.