Effect of Castration and Slaughter Age on the Flavor of Sheepmeat

Abstract

Entire and castrated ram lambs were slaughtered at 12 and 30 weeks of age. Lean tissue from the M. semimembranosus muscle and adipose tissue from the muscle region were recovered. Headspace volatiles, total volatiles, phenols, and free fatty acids were analyzed. Seventy-one compounds were reported as components of lamb aroma for the first time, including 4,6-dimethyl-1,3-oxathiane. Indole, 3-methylindole (skatole) and thiophenols were identified only in tissue from entire animals. Levels of certain alkylphenols and branched chain fatty acids increased with entirety and slaughter age. 3-Methylindole and several of the phenols and branched chain fatty acids identified have been associated with the undesirable note of cooked sheepmeat, while indole has been implicated in boar taint and is reported as a component of sheepmeat for the first time. Sensory analysis revealed that sheepmeat possessed lamby-meaty aromas combined with undesirable odors. An unpleasant odor, described by the attribute `farmyard’, was detected by panelists in samples of mixed lean and adipose tissue and was significantly higher in meat from entires. The increased level of unpleasant odor attributes of entires, especially those slaughtered at 30 weeks, could be due to higher amounts of indoles, branched chain fatty acids and phenols in those samples