Mechanically separated chicken (MSC) reduces the cost of processed meat products; however, it also modifies their texture, flavor, and color. MSC production practices are very diverse, resulting in differences in proximate composition. However, little modern literature has studied the variation in MSC functionality compared to whole muscle chicken raw materials. The objectives of the present work were to assess two types of MSC and chicken breast trim as frankfurter raw materials and to identify rheological attributes of their myofibrillar proteins during gelation. MSC variation was obtained from two separation methods (MSC1, Beehive separator, aged bones; MSC2, Poss separator, fresh bones) and compared to chicken breast trim. Three replications of frankfurters were manufactured from each chicken raw material and pork back fat. Myofibrillar protein solutions 2.8% (w/v) (0.6 M NaCl, 50 mM sodium phosphate, pH 6) from each chicken raw material were evaluated for rheological properties during thermal gelation and cooling.

MSC2 frankfurters were greatest in fat and least in moisture content (P<0.05). Both MSC frankfurters had significantly darker (L*), and redder (a*) external and internal color than BT frankfurters with MSC2 being the darkest and reddest treatment (P<0.05). Greater hardness, cohesiveness, resilience, and chewiness values were observed in MSC2 frankfurters than in BT and MSC1 frankfurters. All myofibrillar solutions exhibited gelation with increased temperature. A peak, decline, and increase was observed in all treatments both in G' and G''. G' slopes on both sides of the peak (S2, S3) and final increase (S4) were significantly different (P<0.05) between BT and both MSCs. BT S2 and S3 were significantly different from MSC treatments in G'' (P<0.05), but not S4.

The data demonstrate that the physical properties of myofibrillar proteins from MSC and chicken breast meat differ during thermal gelation. This indicates a different myofibrillar protein profile that can be explained by both muscle source and by modification during the production of MSC. The data reveal that properties of raw material produced from dissimilar MSC processing can result in significant variation in finished product quality, underscoring the importance of understanding the features of raw materials that affect processing functionality.