Quinoa Protein Hydrolysate as Potential Immunomodulators: Effects on Cytokine Production and Macrophage Activation

High-quality protein and bioactive compounds in quinoa (Chenopodium quinoa Willd) have spotlighted its potential as a functional food ingredient due to its antioxidant, anti-inflammatory, and immunomodulatory effects. This study investigates the immunomodulatory potential of quinoa protein concentrate (QPC), quinoa protein hydrolysate (QPH), and a quinoa peptide fraction (QPF < 3 kDa) for activating macrophages. QPH was prepared via alcalase hydrolysis of QPC, followed by ultrafiltration (QPF < 3 kDa). In vitro and ex vivo assays on mice peritoneal and spleen macrophages were conducted to evaluate the effect of QPC and QPH on cytotoxicity, cytokine profiles (Interleukin (IL)-6, IL-10, Tumour Necrosis Factor (TNF)-α, Interferon (IFN)-γ), and phagocytic activity of macrophages induced by QPC, QPH and QPF. Results indicated that QPC and QPH showed no cytotoxic effects at protein concentrations ≤ 1000 µg/mL. QPH at1000 µg/mL increased the production of IFN-γ and TNF-α, while increasing IL-10 release, suggesting a balanced immunostimulant response. Furthermore, QPF significantly enhanced phagocytic activity in spleen macrophages, emphasizing its role in systemic immune activation. These findings suggest quinoa-derived proteins and peptides hold promise as functional ingredients for immune health applications.