Effect of polyphosphate treatment and electrical stimulation on postchill changes in quality of broiler breast meat

The objective of this study was to assess effects of treating electrically stimulated broiler forequarters with polyphosphates after various aging periods on quality. Ninety-six mixed sex broilers were electrically stunned and slaughtered. Half the carcasses were electrically stimulated during bleeding and half were not. Forequarters were harvested immediately after chilling and after 2, 4, and 6 h postchill. Left forequarters were marinated in salt solution and right forequarters in salt solution plus sodium tripolyphosphate. After marination, the quarters were cooked. Yield and meat pH were evaluated immediately after marinating; and color, yield, and cooking loss were evaluated after cooking. Electrical stimulation resulted in a decline in muscle pH for the 0 postchill group. The pH of muscles from unstimulated and stimulated carcasses from the remainder of the postchill times were equivalent. Phosphate treatment increased pH at all postchill times. Electrical stimulation of the marinated quarters increased cooking loss and decreased yield regardless of marinade composition. Both cooking loss and yield were superior for forequarters harvested at 0 or 2 h postchill compared to those harvested at 4 or 6 h postchill. The phosphate improved moisture binding regardless of electrical treatment or time of harvest. Color values of cooked muscles were unaffected by marination time, but the phosphate-treated muscles had higher b* (yellowness) values than controls. Shear values of unstimulated carcasses that received phosphate treatment were 35% greater than those that received no phosphate treatment. When the carcasses were electrically stimulated, the toughening effect of the phosphate was eliminated.