Influence of the Processing on Composition, Protein Structure, and Techno-Functional Properties of Pork Byproduct Isolates Produced by Isoelectric Precipitation and Ultrafiltration–Diafiltration

The valorization of pork slaughterhouse byproducts presents a promising strategy to reduce the substantial volume of waste generated by the meat industry. In this work, isoelectric precipitation (IEP) and ultrafiltration–diafiltration (UF-DF) were used to produce protein isolates from pork byproducts (PBPI). Both isolates had comparable protein contents (81.73–84.56%) and similar fatty acid profiles, but PBPI-UFDF exhibited better nutritional lipid indices. The amino acid profiles of both isolates exceeded the FAO recommendations. Structural analyses revealed that UF-DF better preserved protein structure, with higher surface hydrophobicity (538.04 vs 77.96 AU), free sulfhydryl content (60.14 vs 16.44 μmol/g), and denaturation temperature (146.04 vs 106.10 °C) compared to IEP. This translated into improved protein solubility across a broad range of pH range (40–95% vs 3–37%) and lower protein aggregation. PBPI-UFDF also showed superior gelation properties, highlighting its potential as a high-quality functional protein ingredient.