Spirulina as a Multifunctional Ingredient: Challenges, Opportunities, Composition, Techno-Functional Properties, and Food Applications.

Spirulina platensis is a nutrient-dense, sustainable microalga with diverse applications across food systems. This review summarizes its technological-functional characteristics, nutritional composition, and contemporary uses in fortified and functional foods. Spirulina is particularly distinguished by its exceptionally high protein content, balanced amino acid profile, high digestibility, and abundance of essential micronutrients, pigments, and bioactive compounds such as phycocyanin, carotenoids, and phenolics. The antioxidant, anti-inflammatory, and probiotic-supporting properties of these constituents establish Spirulina's role as both a bioactive agent and nutritional supplement. Beyond its composition, it exhibits versatile techno-functional properties, including gelation, emulsification, and foaming, that enable it to serve structural and stabilizing roles within complex food matrices. Its proteins and polysaccharides enhance gel strength, emulsion stability, and foam retention, while processing interventions can further improve its functional performance. Spirulina's versatility is reflected in its integration into a variety of food categories, including beverages, snacks, gluten-free and bakery goods, cheese, and meat substitutes. These applications consistently improve protein, mineral, and antioxidant content while maintaining acceptable sensory characteristics when properly formulated. Overall, its rich nutritional composition, multifunctional attributes, recognized safety status, and environmentally friendly production emphasize its promise as a pivotal ingredient for next-generation plant-based and clean-label foods.