Color values and other meat quality characteristics of breast muscles collected from 3 broiler genetic lines slaughtered at 2 ages

Broilers from the lines Ross 308, Ross 708, and Cobb 700 were slaughtered at 28 and 41 d of age at a commercial abattoir. After slaughter, the carcass, breast, and leg weights as well as the breast and leg yields were determined. Further investigations analyzed the color [lightness (L*), redness (a*), and yellowness (b*)], pH at 24 h postmortem, electrical conductivity (EC), drip loss, grill loss, and shear force values as well as the muscle fiber cross-sectional areas of the breast muscles. The 41-d-old broilers had higher carcass, breast, and leg weights than the 28-d-old birds. The breast yield values were higher and the leg yields were lower in the 41-d-old broilers. The fiber cross-sectional area values were also higher in the older birds. Within the younger birds the slaughter characteristics were approximately comparable among the lines. The EC, L*, grill loss, and shear force values increased but the drip loss and a* values decreased with the age of the broiler. The genetic lines differed within the 28-d-old broilers with regard to EC, grill loss, and shear force values and within the 41-d-old broilers with regard to the EC, L*, grill loss, and shear force values. The pH correlated negatively with the EC, L*, b*, drip loss, and shear force values. During storage, L* and b* values of the breast muscles increased and a* values decreased in all genetic lines, whereas the L* values were generally higher in the older broilers and the a* and b* results were generally higher in the breast muscles of the younger broilers. In conclusion, the carcass and meat quality characteristics of broilers changed with age with positive (carcass and breast muscle weight, drip loss) but also negative (L*, a*, grill loss) effects. The effect of the genetic line was rather low. Despite the age-related changes of meat quality parameter, the pH values remained unchanged, indicating muscle structural influences on the muscle-to-meat-transition with increasing age of the broiler.