Effect of different gas stunning methods on Manchega suckling lamb meat packed under different modified atmospheres

Forty-nine Manchega breed male suckling lambs were used in this experiment. The effect of CO2 concentration and exposure time at stunning [80% CO2 for 90 s (G1); 90% CO2 for 90 s (G2); 90% CO2 for 60 s (G3); 80% CO2 for 60 s (G4)] plus an electrically stunned control group (G5) was assessed for pH, colour (L∗, a∗, b∗, C∗ and h∗), water holding capacity (WHC), drip loss (DL), cooking loss (CL) and shear force (SF) in samples packed under two different types of modified atmospheres (MA: MA A: 70%O2 + 30%CO2; MA B: 69.3%N2 + 30%CO2 + 0.7%CO) at 7, 14 and 21 d post-packaging. The lowest pH was found in G4 and in G5. The highest WHC and the lowest CL were found in G2 and G3 groups (P < 0.05). Modified atmospheres did not affect on pH, WHC, CL and DL, although a significant effect (P < 0.001) on colour was found at all the analysis times. Both the type of stunning and the modified atmosphere affected SF values.