Identification of novel umami peptides with anti-inflammatory and antioxidant effects in spent hen protein hydrolysate

Spent hens, a major byproduct of the laying hen industry, were used to prepare umami peptides with anti-inflammatory and antioxidant activities. Among nine hydrolysates, the Protex 6 L-Thermoase product (SPH-6 L-T, 2 mg/mL) showed the strongest umami intensity, comparable to 10 mM monosodium glutamate. In HEK293 cells expressing the type I taste receptor TAS1R1, SPH-6 L-T, at 2 mg/mL, significantly increased intracellular Ca²⁺ mobilization; in tumor necrosis factor α (TNFα)-stimulated endothelial cells, SPH-6 L-T, at 500 μg/mL, significantly reduced cyclooxygenase-2 (COX2) (p = 0.0058) and reactive oxygen species (ROS) (p = 0.0031). Peptidomics identified 1318 di-/tripeptides and 170 oligopeptides. Four peptides (AR, AQ, SKEGGKVT, ELEEEIEAE), all derived from myosin heavy chain, showed strong umami taste (0.2 mg/mL) and favorable docking to the TAS1R1 Venus flytrap domain. Two oligopeptides (5 mM) induced sustained Ca²⁺ responses (> 5 min), and all four reduced ROS (p < 0.0001); SKEGGKVT (50 μM) also significantly inhibited COX2 expression (p = 0.018). These findings highlight spent hens as a good source of multifunctional umami peptides.