Alternative Proteins from Filamentous Fungi: A Pathway to Sustainable Food Systems

The shift toward sustainable protein sources is increasingly recognized as a critical strategy to meet the nutritional demands of a rapidly growing global population while reducing environmental pressures. According to the Food and Agriculture Organization, nearly one billion people worldwide do not consume adequate protein. In this context, filamentous fungi provide a promising solution by bioconverting agro-industrial side streams into mycoproteins, which have up to ten times lower carbon footprints than beef, require fewer resources than conventional proteins, and support both food security and waste valorization. This study explores mycoproteins produced from filamentous fungi cultivated on various low-cost agri-food industries side streams, focusing on nutritional quality, functionality, sensory attributes, and their potential role in the transition to sustainable food systems. Data were collected from international databases, including PubMed, Scopus, Web of Science, and ScienceDirect, using targeted keywords such as mycoproteins, production, applications, safety, regulation, market penetration, and fermentation. Relevant studies were synthesized to provide a comprehensive overview of mycoprotein production, nutritional composition, sensory profiles, technological applications, and regulatory status. Results indicate that mycoproteins are nutritionally dense, with crude protein content ranging from 13.6% to 71% dry weight and a complete amino acid profile. They contain moderate fiber (4.8–25% dw), low fat (>2.9% dw), and carbohydrates (>5% dw), and are rich in essential minerals such as phosphorus, magnesium, zinc, and iron. Functional properties are further enhanced by accumulation of polyphenols (>0.14% dw) during fungal fermentation. Variations in composition and sensory attributes depend mainly on substrate type, nutrient availability, and fungal strains. Efficient bioconversion of agri-food industries side streams can be achieved via submerged or solid-state fermentation, supported by advanced bioreactors and AI-driven process optimization. Furthermore, regulatory approvals in Europe and beyond confirm their safe integration in food systems. In conclusion, this study underscores that mycoproteins can alleviate global protein deficiencies, reduce reliance on animal sources, and support nutritious, healthy diets. Future perspectives suggest that leveraging biotechnological innovations will enhance the production efficiency, functional properties, and sensory qualities of filamentous-fungi-derived proteins, positioning them as a pillar of future sustainable and circular food systems.