Unlocking the Potential of Yeast Protein for Functional Foods: A Multiscale Overview of Bioactivity, Processing, and Application Challenges

Global shifts in protein supply and demand are reshaping food systems toward sustainability and multifunctionality. Benefiting from its microbial biosynthesis advantage, balanced amino acid profile, and tunable molecular structure, yeast protein exhibits distinctive interfacial, colloidal, and bioactive functionalities that differentiate it from other microbial proteins. These support the potential use of yeast protein as a versatile ingredient in the structural and functional design of food systems. Despite increasing research attention, previous reviews have not systematically integrated source variability, extraction and fractionation strategies, processing-induced structural transformations, and interfacial/colloidal behavior with final food functionality. This review addresses these gaps by linking compositional features and multiscale structure-function relationships to emulsifying, foaming, and gelling behaviors across food matrices. However, commercialization is still restricted by compositional heterogeneity, sensory defects, process scalability, and the lack of standardized safety and performance evaluation. This review integrates advances in structural regulation and functional mechanisms to provide a clearer framework for performance optimization and practical translation of yeast protein in food systems.