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.

Volatile Profile of Grilled Lamb as Affected by Castration and Age at Slaughter in Two Breeds

“…Pyrazines are nitrogen-containing heterocyclic compounds that are formed through the Maillard reaction (Mottram, 1998). They have a "grilled meat" or "roasted" odor note, low vapor pressure and low odor threshold (Table 1) and have been previously reported, following GC-olfactometry, (GC-O) as important odor-impact volatiles in cooked lamb muscle (Frank et al, 2017;Resconi et al, 2010;Watkins, Frank, Singh, Young, & Warner, 2013). In agreement with the data relating to pyrazines, the sensory study (Gkarane et al, 2017) using the same animals as those used in this study showed that lamb from castrates had higher (P < 0.05) Intensity of Roast Meat Aroma and Intensity of Roast Meat Flavor than lamb from rams.…”

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Volatile organic compounds and consumer preference for meat from suckling goat kids raised with natural or replacers milk

“…Other minority VOC were also found in suckling light lambs such as 1-pentanol (Vieira et al 2012). Ethyl acetate has a positive relationship with barnyard odour (Frank et al 2017). Alkyl pyrazines such as 2,5 dimethyl pyrazine have a very low odour threshold (Fors and Olofsson 1985).…”

“…2-pentyl furan was also found in suckling lambs fed MR (Mor an et al 2014). This VOC is associated with beany, grassy (Drumm and Spanier 1991) and liver (Frank et al 2017) flavour.…”

“…The aldehydes 2methyl propanal, 2-methyl butanal and 3-methyl butanal are generated in the Strecker degradation of valine, leucine and isoleucine, respectively, and have been reported to contribute considerably to the overall flavour of meat products (Andrade et al 2010). 2methyl propanal has been associated with barnyard odour (Frank et al 2017), while 3-methyl butanal has been associated with ripened flavour (Careri et al 1993).…”