Insights into saltiness enhancement effect and processing stability of pea-derived peptides using psychophysics and...

Excessive sodium intake constitutes a critical global health challenge. Saltiness-enhancing peptides offer a promising alternative for reducing dietary sodium without compromising perceived saltiness. This study characterized six pea-derived peptides for their saltiness-enhancing effects, interaction patterns with NaCl, and stability under food-processing conditions. Sensory evaluation combined with psychophysical analyses revealed that both peptides and NaCl produced concentration-dependent increases in saltiness perception. Quantitative modeling using S-curves and σ-τ plots demonstrated additive interactions across concentrations, while zero-interaction planes analysis identified a maximal synergistic effect at 4 mg/mL NaCl combined with 2 mg/mL peptide. Molecular docking analysis suggested that these negatively charged peptides may interact with the TMC4 channel protein and associated ionic environment, potentially contributing to saltiness enhancement. Stability testing further indicated that the peptides remained relatively stable under mildly alkaline conditions (pH 8), while IYDYD and DYWPS also exhibited good thermal stability across temperatures relevant to typical food-processing conditions. Together, these psychophysical, computational, and stability analyses provide an integrated quantitative framework for optimizing peptide-NaCl interactions and support the potential applicability of pea-derived saltiness-enhancing peptides for sodium-reducing strategies for food systems.