Fatty acid, volatile and sensory characteristics of beef as affected by grass silage or pasture in the bovine diet

•IMF decreased with feeding grazed grass prior to concentrate finishing.•Muscle fatty acids and volatiles reflected grazed grass/grass silage feeding.•The grazed grass effect on muscle composition persisted after concentrate finishing.•Sensory differences were correlated with IMF and some fatty acids. Fatty acids, volatile compounds and sensory attributes of beef from bulls fed concentrates to slaughter (C), grass silage for 120days (GS) followed by C (GSC), or GS followed by 100days at pasture and then C (GSPC), and slaughtered at 3 target carcass weights, were determined. Total intramuscular fat (IMF) was lower for GSPC than for GSC and C. C18:3n–3 concentration and polyunsaturated fatty acid (PUFA) to saturated fatty acid (SFA) ratio were higher and C18:2n–6 and monounsaturated fatty acid concentrations and n–6:n–3 PUFA ratio lower for GSPC than C. C16:0, C18:0 and C18:1c9 increased with carcass weight when expressed quantitatively, but not when expressed proportionately. Hexanal concentration was higher and 2-methyl-1-butanol and toluene lower for C and GSC than for GSPC. Overall liking was negatively correlated with C20:5n–3 and PUFA/SFA ratio, but differences in sensory attributes (tenderness, flavour liking, overall liking) were most strongly correlated with IMF.