In vitro antidiabetic and antioxidant activities of protein hydrolysates via alkaline autolysis of Fusarium venenatum mycoprotein

The mycoprotein from Fusarium venenatum, characterized by its abundant proteins could be a valuable candidate for autolysis, potentially contributing in the production of bioactive compounds. In this study, four autolysis methods, including acidic, alkaline, plasmolysis, and enzymatic hydrolysis were applied to enhance the extraction of bioactive compounds. The resulting protein hydrolysates were evaluated for their antioxidant properties, α-amylase and α-glucosidase inhibition, antibacterial activity against Escherichia coli, Salmonella spp., and Staphylococcus aureus, antifungal activity against Aspergillus niger, and structural characteristics. Antioxidant assays revealed that alkaline autolysates exhibited the highest activity (DPPH: ~ 556 µmol Trolox/g sample; ABTS: ~ 235 µmol Trolox/g sample), demonstrating approximately twice the inhibitory capacity compared to mycoprotein. The inhibitory effect on α-amylase was attributed to the porous structure of mycoprotein, which led to substantial physical entrapment of the enzyme (~ 62%). In contrast, α-glucosidase inhibition was primarily associated with the degree of hydrolysis and peptide structure, with alkaline autolysates (~ 35%) exhibiting the highest inhibitory activity. These findings suggest that α-glucosidase inhibition is likely due to structural interactions altering enzyme function, whereas α-amylase inhibition results from a physical entrapment mechanism. Despite their strong antioxidant and enzyme-inhibitory properties, neither mycoprotein nor the protein hydrolysates exhibited significant antimicrobial activity. These findings indicate that alkaline lysis of mycoprotein could serve as a source of bifunctional compounds with natural antioxidant and antidiabetic properties, making them valuable for the development of functional food formulations.