Innovations in Egg Alternatives: Sustainable Sources, Novel Technologies, Challenges, and Future Perspectives

Researchers are developing egg alternatives to match the nutritional, sensory, and techno-functional properties of conventional eggs, but no single alternative ingredient currently replicates the full multifunctionality of eggs. This review critically evaluates recent advances in egg-alternative systems, with an emphasis on alternative proteins and functional ingredients. Comparative evidence indicates that several legume proteins, like adzuki and cowpea, can provide strong egg-like functionality. Protein concentrates can also provide improved functional performance at lower concentrations than corresponding isolates, whereas cereal proteins generally face limitations related to solubility, foaming, and emulsification. Hydrocolloids, starches, fibers, and aquafaba can further improve gelation, emulsion stability, and foam structure, although their effects depend strongly on formulation and processing conditions. Despite these advances, the principal functional gap remains the simultaneous replication of egg functionalities within a single formulation. Nutritionally, plant-based systems commonly remain limited by incomplete amino acid profiles and lower levels or bioavailability of micronutrients such as vitamins. The evidence therefore supports a design strategy based on complementary protein blends, controlled protein–polysaccharide–lipid interactions, targeted fortification with attention to bioavailability, and processing technologies that improve functionality without compromising sensory quality. Future development should prioritize multifunctional formulations validated against egg benchmarks using standardized functional, nutritional, sensory, and digestibility measurements.