During postmortem storage, the muscle undergoes a series of biochemical, histological, and physical events, all together called rigor mortis. If one or several of these events are modi‘ed, product acceptability may be altered (StifŽer and others 1982). Tenderness, in addition to color and Žavor, is considered the most important characteristic of meat (Savell and others 1977; McKeith and others 1979; Elgasim and others 1981; Soria and Corva 2004; Castañeda and others 2005). Looking for an ef‘cient postmortem tenderizing method is a result of consumers’ demand for good tasting and uniform quality meat (StifŽer and others 1982). Several researchers developed methods to improve meat tenderness; muscle contractile proteins, connective tissue, or both are usually affected by these processes.