Effects of Chicken Skin Protein Hydrolysate and Bone Protein–Mineral Mass on the Quality of Emulsified Poultry Sausages

The poultry industry generates large amounts of protein- and mineral-rich by-products that remain underutilized. This study investigated the use of chicken skin protein hydrolysate and chicken bone protein–mineral mass (PMM) as functional ingredients in emulsified poultry sausages. The hydrolysate was characterized by a high protein content (52.25%) and high water- and fat-binding capacity (142% and 125%, respectively), while the PMM served as a source of protein and minerals with stable physicochemical and rheological characteristics. These ingredients were incorporated into sausage formulations at different substitution levels. Partial replacement of poultry meat increased protein and mineral content and affected key technological properties, including water-binding capacity, emulsion stability, cooking loss, and shear force. Moderate inclusion levels were associated with a more cohesive protein matrix, lower cooking losses, and improved structural stability, whereas excessive substitution resulted in increased firmness and less favorable sensory characteristics. Among the tested formulations, the combination of 18% PMM and 4% protein hydrolysate showed the most balanced technological and sensory performance. The findings suggest that poultry by-products processed into functional ingredients may have potential for application in value-added sausage formulations.