From isolate to concentrate: Insights into the texturization of pea protein systems during high-moisture extrusion

Pea protein ingredients vary widely in composition and functional properties depending on their processing history, which strongly affects their behavior during high-moisture extrusion. This study compared pea protein isolate (PPI, 81% protein), pea protein concentrate (PPC, 52% protein), and a 1:1 blend (PPC–PPI, 67% protein) to elucidate how raw material properties influence protein aggregation and the resulting texture of meat analogues processed at high moisture contents (50–60%). PPI exhibited low solubility, high water-holding capacity (WHC), and a partially denatured protein state, whereas PPC contained higher levels of carbohydrates and fiber, showed greater solubility, and retained a more native protein structure. These differences resulted in distinct rheological responses: PPI dispersions formed dense, elastic networks at ambient temperature, while PPC showed limited initial structure but pronounced heat-induced gelation; the blend exhibited comparatively low viscosity and elasticity. During extrusion, PPI formed predominantly disulfide-stabilized networks, resulting in high hardness and anisotropy at low moisture (50%). In contrast, PPC aggregated mainly via non-disulfide covalent bonds, producing stiff but brittle structures. The PPC–PPI blend showed moisture-dependent behavior: at high moisture (60%), enhanced non-covalent interactions promoted molecular mobility and alignment, whereas at low moisture increased non-disulfide covalent cross-linking strengthened the network but constrained anisotropy. Correlation analysis confirmed that aggregation pathway, rather than protein content alone, governs extrudate texture. Overall, controlling the balance between disulfide, non-disulfide, and non-covalent interactions is critical for optimizing strength and alignment during high-moisture extrusion of pea proteins, highlighting blending as a practical strategy to tailor texture while leveraging the sustainability advantages of dry-fractionated proteins.