A Simple Method for Following Rigor Mortis Development in Beef and Poultry Meat

A routine method based on measurement of (post-mortem conversion of adenosine nucleotides to inosinic acid was developed for following the onset of rigor mortis in beef and chicken muscles. Conversion of adenosine nucleotides to inosinic acid was accompanied by a decrease in absorbance at 258 mμ and an increase at 250 mμ.The ratio of the two absorbance measurements changed linearly with the ratio of adenosine nucleotides and inosinic acid. Immediately after slaughter, the absorbance ratio was about 1.2 in both beef and poultry muscles, but gradually dropped to a value of 0.84–0.89 during the onset of rigor mortis as determined by isometric tension development. This value of the absorbance ratio at rigor was confirmed also by comparison with phosphate ester, adenosine triphosphate, and shear force measurements. Besides being simple and rapid, the method is accurate since it indicates indirectly the adenosine triphosphate content of the muscle tissue, the determining factor in rigor mortis.