Optimization of fungal protein extraction and studies on physicochemical properties and functional characteristics

Fungal protein isolate (FPI) was successfully extracted from the mycelium of a strain isolated from traditional Chinese Mao-Tofu under alkaline conditions. Response surface methodology optimized the extraction, achieving a 36.50 % yield with 58.24 % protein content under ideal parameters (pH 11.5, 45 °C, 30 mL/g solvent: solid ratio, 70 min). Protein electrophoretic characterization revealed FPI’s main subunits at 11.7, 35.4, and 56.7 kDa. Critically, FPI exhibited pronounced pH-dependent structural and functional properties: near its isoelectric point (pI ∼3.4), it displayed maximal ordered secondary structure (76 % α-helix & β-sheet at pH 3.0) and formed large aggregates, while alkaline conditions induced high solubility, small particle size, low surface hydrophobicity, and elevated free thiol content. These findings demonstrate FPI’s strong potential as a functional, pH-responsive alternative protein for food industry applications.