Pre rigor processing, ageing and freezing on tenderness and colour stability of lamb loins

Abstract

Forty eight lamb carcasses with temperature and pH monitored were obtained from two commercial plants. At 24h post mortem both loins (M. longissimus) from each carcass were randomly allocated to a) unaged frozen at −18°C, (b) aged at −1.5°C for 2weeks before freezing, (c) aged for 3weeks before freezing and (d) aged for 9weeks without freezing. Shear force, colour stability and proteolysis were analyzed. Carcasses with a slower temperature and more rapid pH decline had more calpain autolysis, slightly higher shear force and less colour stable compared to that counterpart in general (P<0.05). However, the shear force values of the loins were all acceptable (<6kgF) regardless of different pre rigor processing and ageing/freezing treatments. Furthermore, the loins aged for 2weeks-then-frozen/thawed had a similar shear force to the loins aged only for 9weeks suggesting that ageing-then-freezing would result in equivalent tenderness compared to aged only loins for the long-term storage.