Effect of stress-related changes in sheepmeat ultimate pH on cooked odor and flavor

In this study sheepmeat with a moderate or high ultimate pH (mean pH 6.26 and 6.81, respectively), which was induced by preslaughter adrenaline injection, had a significantly lower overall cooking odor and flavor intensity, as assessed by a trained sensory panel, than sheepmeat of a more acceptable pH (5.66). Panelists also found that desirable odor and flavor notes decreased and undesirable ones increased as ultimate pH increased. Purge and trap gas chromatography/mass spectrometry of fat rendered during cooking identified 57 (of a total of 325) volatile compounds that significantly decreased in concentration with increasing pH. Aldehydes were the most common compounds identified. Gas chromatography/olfactometry identified 54 odor-active compounds. Ten of these were also found to be responsive to changes in meat ultimate pH. Most of these compounds were aldehydes. Therefore, these results show that sheepmeat odor and flavor are dramatically affected by elevated meat pH.