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

Abstract The increasing demand for plant-based proteins, particularly quinoa (Chenopodium quinoa Willd.), has spotlighted its potential as a functional food ingredient due to its high-quality protein content and bioactive compounds and a range of health-promoting properties, including 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 < 3kDa) in regulating cytokine production and activating macrophages. QPH was prepared via QPC alcalase hydrolysis, followed by ultrafiltration (QPF < 3 kDa). In vitro and ex vivo assays on BALB/c mice peritoneal and spleen macrophages were conducted to evaluate cytotoxicity, cytokine profiles induced (Interleukin (IL)-6, IL-10, Tumor Necrosis Factor (TNF)-α, Interferon (IFN)-γ), and phagocytic activity of macrophages. 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 pro- and anti-inflammatory response. Furthermore, QPF significantly enhanced phagocytic activity in spleen macrophages, underscoring its role in systemic immune activation. These findings suggest quinoa-derived proteins and peptides hold promise as functional ingredients for immune health applications.