Impact of white striping on functionality attributes of broiler breast meat1

The influence of white striping (WS) on the water-holding capacity (WHC) and protein functionality attributes of broiler breast meat was investigated. Boneless breast fillets (Pectoralis major) were collected from the deboning line of a commercial processing plant and categorized by WS score (normal, moderate, severe). The physical (weight, pH, CIE-color values), water-holding capacity (salt-induced water uptake, cook loss, final yield), protein functionality (solubility, emulsifying activity), and protein composition (SDS-PAGE) characteristics of the fillets were measured in three experiments. Breast meat with WS exhibited greater fillet weights, higher pH, and similar color values (L*a*b*) to normal fillets. In experiment 1, fillets were frozen-thawed prior to analysis. The WS condition reduced thaw loss, sarcoplasmic protein solubility, and the emulsifying activity of the myofibrillar proteins, but did not significantly affect salt-induced water uptake, cook loss, final yield, or myofibrillar protein solubility. In experiment 2, breast meat was analyzed fresh and after a freeze-thaw cycle. Freezing samples prior to analysis negatively influenced WHC and reduced sarcoplasmic protein solubility in both WS and normal fillets. In fresh and frozen-thawed meat, the WS condition decreased sarcoplasmic protein solubility but did not significantly alter WHC or myofibrillar protein solubility. For experiment 3, fillets were portioned into 3 sections (Location A, cranial end-ventral surface; Location B, cranial end-dorsal surface; Location C, caudal end). The effects of WS on WHC and protein solubility were dependent upon breast fillet sampling location. Fillets with WS exhibited lower salt-induced water uptake, greater cook loss, and lower sarcoplasmic protein solubility than normal fillets when sampled from location A. SDS-PAGE analysis indicated that differences in the composition of sarcoplasmic and myofibrillar protein fractions between WS and normal fillets were influenced by sampling location. These results suggest that WS diminishes the WHC and protein functionality of broiler breast meat, but demonstrate that the WS effects on these traits are not uniform throughout the breast muscle.