Nutrient‐rich algal innovation: exploring the amino acid profile, flavor, antioxidant, immunomodulatory, and cytotoxic properties of
Chara corallina
Kangsadan Boonprab, Sunisa Kongthong, Wanninee Chankaew Abstract
BACKGROUND
The exploration of sustainable and functional plant‐based protein sources has gained momentum amid rising global demands for health‐oriented food innovations. This study investigates the nutritional and biofunctional properties of a powdered protein sauce derived from Chara corallina , a freshwater macroalga recognized for its high protein potential.
RESULTS
Dried C. corallina fronds (17.3% protein) were fermented with Aspergillus sojae using koji and moromi processes under open‐air conditions. The resulting sauce was freeze‐dried into algal protein powder (APP‐C). Amino acid analysis revealed significant increases ( P ≤ 0.05), especially in tryptophan (16.09%), nearly absent in unfermented C. corallina . This highlights APP‐C as a rich dietary source of tryptophan, a serotonin precursor linked to mood and immune health. Aspartic acid, glutamic acid, and cysteine were also elevated, while methionine was absent. These changes enhanced umami flavor and reduced sweetness. APP‐C exhibited no cytotoxicity at concentrations of 3.90–500 μg mL −1 across RAW264.7 macrophages, human dermal fibroblast (HDF) cells, and rat skeletal muscle (L6) cells, with > 90% cell viability confirmed by the thiazolyl blue tetrazolium bromide (MTT) assay. Antioxidant potential was evidenced by significant up‐regulation ( P < 0.05) of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) messenger RNA (mRNA) expression in HDF cells under oxidative stress induced by hydrogen peroxide (H 2 O 2 ). Moreover, immunomodulatory assessments of APP‐C revealed dose‐dependent stimulation of nitrite production, phagocytic activity, and gene expression (lysozyme M, tumor necrosis factor‐α, and interleukin‐8) in RAW264.7 cells ( P < 0.05). These findings exhibited strong antioxidant and immunomodulatory activity.
CONCLUSION
APP‐C represents a promising fermented functional food from sustainable, health‐promoting freshwater algae. © 2026 Society of Chemical Industry.