An integrated sensory, consumer and olfactometry study evaluating the effects of rearing system and diet on flavour characteristics of Australian lamb

Abstract

Producing lamb with good eating quality – flavour, tenderness and juiciness – is essential for consumer satisfaction. Forages such as lucerne and plantain can play an important role in sustainable lamb production; however, it is important to ensure that these feeds do not introduce undesirable flavours. We evaluated the potential for backgrounding (post-weaning) and finishing diets (11 weeks pre-slaughter) to affect lamb eating quality. Lambs were backgrounded on either (1) a combination of three cultivars of perennial ryegrass or (2) a combination of lucerne, ryegrass and fescue and then finished (76 days) on one of three forages; (1) perennial ryegrass (Lolium perenne), (2) lucerne (Medicago sativa) or (3) plantain (Plantago lanceolota). After slaughter, striploin (M. longissimus thoracis et lumborum) and topside (M. semimembranosus) muscles were removed. Grilled striploins were subjected to consumer acceptance studies and quantitative descriptive analysis by a trained sensory panel. Grilled meat from lambs finished on lucerne and plantain was equally or more acceptable than on ryegrass, with no negative impacts on flavour. The backgrounding system affected flavour attributes as well as tenderness. Grilled lamb volatiles were comprehensively characterised by gas-chromatography-mass spectrometry-olfactometry. Specific flavour-related sensory attributes were modelled using semi-quantitative volatile data. Targeted analysis of branch-chained fatty acids, 4-methylphenol and 3-methylindole indicated no significant effects of backgrounding regime or finishing feed. We conclude that neither lucerne nor plantain had negative impacts on lamb flavour although different combinations of backgrounding and finishing feeds may affect lamb tenderness.