Influence of Postmortem Changes in Bovine Muscle on the Water‐Holding Capacity of Beef. Postmortem Storage of Muscle at 20°C

Abstract

ABSTRACTRigor mortis occurs in bovine neck muscles as soon as pH 5.9 and an ATP level of about 1 μMol/g are reached. At 20°C muscle contraction does not occur before the onset of rigor. Postmortem changes in water‐holding capacity (WHC) were followed by measuring the cooking loss of unsalted and salted (2% NaCl) muscle homogenates prepared after storage of the intact muscle tissue at 20°C for different periods postmortem. At tissue pH above 5.9 addition of salt causes a strong increase of WHC of muscle homogenates. There is a small decrease of WHC of both unsalted and salted homogenates during the prerigor phase which is apparently caused by the postmortem fall of pH. Rigor mortis does not influence the WHC of unsalted muscle homogenates but causes a strong decrease of WHC of salted homogenates. The reason for this difference is discussed. No more than one‐third of the total postmortem decrease of WHC and protein solubility in salted muscle homogenates was attributed to the fall of pH, so at least two‐thirds were due to the development of rigor.