Time in Lairage and Chilling Affect Lamb Carcase Quality29 November 2013
Actions and interventions taken both pre-slaughter in the lairage and post slaughter in chilling and ageing can have different effects on meat quality.
Two studies from Spain looked at the effect of the time speant in the lairage at the slaughterhouse had on lamb and also the different chilling regimes.
In the first study, researchers from Department of Food Technology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria in Madrid, the Universidad Complutense de Madrid and the Estación Tecnológica de la Carne (ITACyL), Consejería de Agricultura y Ganadería de Castilla y León in Salamanca, Spain looked at the effect of different lairage times on suckling lambs and found that live weight losses increased by about 0.34 per cent per hour in lairage.
The Glycogen content of liver and longissimus muscle also decreased as lairage time increased.
Lambs that were kept three hours in lairage showed the highest ultimate pH of longissimus muscle and the effects of the lairage time on texture and WHC disappeared after storage.
The study by M.T. Díaz, C. Vieira, C. Pérez, S. Lauzurica, E. González de Chávarri, M. Sánchez and J. De la Fuente and published in the journal Meat Science looked at the effect of slaughter at arrival (L0) or after three (L3), six (L6) and 12 (L12) hours of lairage on carcase and meat quality of suckling lambs.
Lairage time had a slight effect on carcase quality traits, but most of the meat quality parameters at 24 hours post mortem were affected.
Weight losses increased and glycogen content of liver and longissimus muscle decreased as lairage time increased.
Longissimus muscle from the lambs in lairage for three hours had the highest pH, shear force and toughness and the lowest b* and C* values, at 24 hours post mortem.
Those in lairage for three and six hours had the higher proportion of expelled juice, or low water holding capacity (WHC), at 24 hours post mortem.
Texture parameters and water holding capacity were similar among groups after five days of storage.
Despite the fact that the effects of lairage time on meat quality disappears after storage, from the point of view of weight losses the slaughter of suckling lambs at arrival is recommended.
In another study by C. Vieira and A.M. Fernández from the Estación Tecnológica de la Carne at the Instituto Tecnológico Agrario in Salamanca, the effect of ageing time on suckling lamb meat quality resulting from different carcase chilling regimes was examined.
The study found that after ageing, ultra-fast chilling did not achieve slow chilling tenderness values and the researchers concluded that slow chilling could be an alternative to achieve a high degree of tenderness.
The study looked at the effect of ageing on suckling lamb carcases subjected to three chilling treatments - Conventional (2 °C for 24 hours), ultra-fast (− 20 °C for 3.5 hours then 2 °C until 24 hours post mortem) and slow chilling (12 °C for seven hours then 2 °C until 24 hours post mortem).
Meat quality measurements were carried out on the carcases at 24 hours post mortem and also after five days of ageing.
Carcase chilling losses were not affected by a chilling regime.
Aged meat showed higher cooking losses than non-aged meat (p < 0.05).
Sarcomere length of ultra-fast treatment was shorter (p < 0.05) than conventional and conventional was shorter than slow chilling treatment (p < 0.05), at 24 hours and after five days of ageing.
Conventional and ultra-fast chilling treatments resulted in higher shear force values at 24 hours post mortem (p < 0.05) compared to slow treatment.
All treatments improved sensory scores with ageing (p < 0.05), but ultra-fast chilling treatment did not attain higher values as the other two treatments.
You can view the full report on the lairage effects by clicking here.
You can view the full report on the carcase chilling effects by clicking here.