The effect of diet on the flavour of cooked beef and the odour compounds in beef fat

Fatty meat from cattle finished for nine weeks on ryegrass/clover or maize was evaluated for intensity of pastoral odour and flavour by a sensory panel. Although there was no significant treatment effect for intensity, panellists’ comments indicated that even this short period on a maize diet could change descriptions of odour and flavour; when assessed by independent assessors, the pasture treatment had a much lower ratio of “favourable” to “unfavourable” comments ( P < 0.01). Odorous compounds in fat from the two treatments were examined by odourport sniffing, where compounds eluting from a gas chromatographic column were described, and identified where possible. Two “sniffers” semiquantitatively evaluated the fat volatiles, first trapped on Tenax then resolved on a column. Comparisons between treatments were largely unproductive. However, particularly odorous compounds were tentatively identified along with others of interest with respect to dietary origins. Compounds included 4‐heptenal (and/or the coeluant heptanal), l‐octen‐3‐ol, nonanal, 2,6‐nonadienal, nonanoic acid, and the faecal‐smelling compound indole. 4‐Methylphenol was not detected by sniffing but was present in the fat headspace. The chemical origins of these compounds are discussed in relation to diet.