Fatty acid composition and sensory characteristics of lamb carcasses from Britain and Spain

Fatty acid composition of intramuscular fat in M. Longissimus was measured in four groups of lambs representing two Spanish breeds: Rasa Aragonesa (RA ) and Merino (ME) and two British lamb types: the Welsh Mountain breed (WM) , whose carcasses were purchased in Spain and typical early lambs (EL) purc hased in Britain. The lambs grown in Spain were concentrate fed and slaught ered at a lighter weight and lower age than those grown in Britain. The Bri tish lamb carcasses purchased in Spain were of a similar weight to the Span ish lambs but were lighter than the lamb carcasses purchased in Britain. Th e British lambs were grass fed. Relationships between fatty acid (FA) compo sition and sensory attributes were examined following sensory testing of al l lambs by both British and Spanish taste panels. The production system was shown to be more important than breed in determining FA composition. Briti sh lambs had higher percentages, within total fatty acids, of 18:0, 18:3 (n -3) and long chain polyunsaturated n-3 FA and lower percentages of 18:2 (n- 6) and long chain polyunsaturated n-6 FA than Spanish lambs. These differen ces were due to the different feeding systems used. The amounts of these FA in muscle (mg/100 g) were also different between the British and Spanish g roups, not only because the British lambs had more total fat. For both tast e panels, odour and flavour intensity were positively correlated with the a mounts and percentages of 18:0 and 18:3 and negatively correlated with thos e of 18:2. This was explained by the fact that both panels gave higher odou r and flavour intensity scores to the grass-fed British lamb with high 18:3 levels and lower scores to the concentrate-fed Spanish lamb with high 18:2 levels. However, 18:0 and 18:3 were positively correlated with Savour qual ity and overall appraisal for the British panel and negatively for the Span ish panel. Conversely, 18:2 was a positive contributor to flavour and overa ll preference for the Spanish panel and was negative for the British panel. The results show that the production system affects muscle fatty acid comp osition and the flavour of lamb. However, people's preference is determined to a large extent by their past experience. (C) 2000 Elsevier Science Ltd. All rights reserved.