Breed, slaughter weight and ageing time effects on consumer appraisal of three muscles of lamb.

Consumers (n=265) tasted semitendinosus (ST), semimembranosus (SM) and gluteo biceps (GB) (right and left) from 180 entire male lambs. Muscles were from three Spanish breeds: Rasa Aragonesa (local meat breed), Churra (local dairy breed) and Spanish Merino. Within breed, three slaughter live weights were considered (10-12, 20-22 or 30-32 kg). Isolated muscles were aged under vacuum package for 1, 2, 4, 8 or 16 days. Consumers evaluated tenderness, flavour quality and overall acceptability. Globally, the three attributes were significantly influenced by breed, slaughter live weight and ageing. Considering breed effect, Churra had the lowest scores for tenderness in the heaviest lambs while Spanish Merino was the most tender at 20-22 kg but there were no differences between either for 10-12 kg lambs. Muscles from the heaviest lambs were considered the toughest and those from the 10-12 kg lambs the most tender. Tenderness improved with ageing, but more for SM and GB. Flavour was better in the lightest lambs and, in general, it was not affected negatively by ageing. Consumers preferred meat from the 10-12 kg lambs in all breeds (the most tender and with the best flavour) and aged for intermediate to long periods (4-16 days). For the three attributes, the ST muscle had the best ratings at short ageing times and GB at long ageing times.