Reformulation of Emulsion-Type Pork Sausage Using Collagen and Plasma Proteins as Soy Protein Substitutes for Soy-Free Product Development

The present study evaluated the feasibility of replacing soy protein isolate with collagen and plasma proteins, either individually or in combination with κ-carrageenan, xanthan gum, and sodium tripolyphosphate, in an emulsion-type pork sausage, based on selected physicochemical, compositional, and textural quality parameters. Six formulations were produced, including a control and five reformulated variants in which soy protein was fully replaced by a mixture of collagen (1.88%) and plasma proteins (3.4%), used alone or supplemented with κ-carrageenan (1.0%), xanthan gum (0.2%), and sodium tripolyphosphate (0.2%). Moisture, protein, fat and collagen contents, color, pH, and sensory properties were analyzed after processing, while TBARS values and textural properties were assessed initially and after 30 days of storage. As a result of the reformulation, collagen content increased by 32.35–40.33%, while the collagen-to-protein ratio remained within legal limits (<20%). Soy protein replacement increased textural parameters, including hardness, cohesiveness, gumminess, chewiness, and shear force. Carrageenan and sodium tripolyphosphate enhanced texture and oxidative stability, whereas xanthan gum negatively affected texture quality and sensory acceptance. The formulation containing collagen, plasma proteins, carrageenan (1%) and sodium tripolyphosphate (0.2%) achieved the highest sensory scores, comparable to those of the control. The results show that replacing soy protein in an emulsion-type pork sausage is feasible when using optimized combinations of collagen, plasma proteins, and κ-carrageenan systems.