The relationship between ATP and R-values in postmortem bovine Longissimus dorsi muscle.

To study the relationship between ATP and each of three R-values (R248, R250 and R258) in beef longissimus dorsi muscle data, appropriate mathematical functional forms were estimated by the Box-Cox transformation and then tested for linearity. Two separate tests for linearity indicated that the relationships between ATP and the three R-values were nonlinear. A shifting parameter restriction on the Box-Cox model was used to produce a curve that was more parallel to the y axis in the lower range of x axis, but the restriction lowered the R(2) compared with the Box-Cox model. ATP (1 μmol) could be estimated by R248 of 0·925, R250 of 0·967 and R258 of 1·038 with standard errors of 0·033, 0·034 and 0·032, respectively. There were no significant differences among the three R-values for the prediction of ATP, but there was a suggestion that R258 was the preferred R-value for predicting ATP in beef muscle.