Structural, Interfacial, Gelling, and Digestive Properties of Protein from Grifola frondosa Fruiting Body

Culture medium formulation influences mushroom yield and composition, but its effect on the properties of edible fungal protein remains unclear. To explore the functional and nutritional properties of proteins from Grifola frondosa (GF) fruiting bodies, the study examined the structural, interfacial, gelling, and digestive properties of GF proteins grown in four culture media. The four GF proteins obtained were labeled GFP1–GFP4, respectively. The β-turn content and intrinsic fluorescence in GFP1 increased by 41.48% and 36.45% (p < 0.05), respectively, compared to GFP4. GFP4 exhibited higher surface pressure at the air–water interface and lower interfacial force at the oil–water interface. In comparison with GFP4, the other GFPs showed a higher rate of interfacial film formation and greater film elasticity and strength. GFP2 had a minimum gelling concentration of 80 mg/mL, which is a 33.33% reduction from GFP4. The storage modulus (G′) of GFP1 was 58 times higher than that of GFP4 (10 Pa), indicating a significant increase in gel elasticity (p < 0.05). Additionally, compared to GFP4, GFP1 showed a 16.59% increase in total amino acid and a 6.82% increase in free amino group release (p < 0.05), although its digestibility decreased by 5.06% (p < 0.05). These results suggest that the formulation of the culture medium alters the structures and interfacial properties of GFPs, thereby impacting their functionalities and applications in food colloid-based products.