Effect of ageing prior to freezing on colour stability of ovine longissimus muscle

The effect of different ageing periods (0, 2 and 3 weeks at −1.5 °C) of lamb loins (n = 24) prior to freezing (9, 7 and 6 weeks at −18 °C, respectively) compared to the aged-only (never frozen) lamb for 9 weeks postmortem on colour stability during display was assessed under high-oxygen modified atmosphere (HiOx-MAP; 80% O2) and oxygen permeable overwrap packaging conditions. The aged/frozen loins and aged-only loins in HiOx-MAP had similar (P > 0.05) surface redness, colour intensity, and discolouration. Further, no significant difference found in shear force between the loins aged 3 weeks/frozen 6 weeks and the aged-only loins. However, more lipid oxidation (P < 0.05) was found in the aged-only compared to the aged/frozen loins in HiOx-MAP throughout display. These results suggest that ageing loins prior to freezing would provide equivalent tenderness and colour stability, and better lipid oxidation stability compared to the aged-only loins under HiOx-MAP.