Microalgal exopolysaccharides as emerging food hydrocolloids: Structure–Rheology relationships, bioactivity, and industrial potential

Microalgal exopolysaccharides (EPSs) are emerging as promising next-generation food hydrocolloids with
distinctive structuring and biofunctional attributes. This review critically evaluates the taxonomic diversity,
molecular architecture, and structure–rheology relationships of microalgal EPSs, highlighting how charge density,
branching, and sulfation patterns translate into viscosity, gelation, and interfacial behaviours relevant to
complex food matrices. Recent advances in cultivation strategies, bioreactor design, and downstream processing
are summarized with an emphasis on yield, techno-functional quality, and integration into biorefinery concepts.
Particular attention is given to solution and gel properties, emulsification and film-forming capacity, and synergistic
interactions with established hydrocolloids and food biopolymers in applications such as dairy and plantbased
analogues, beverages, and confectionery. The bioactive potential of microalgal EPSs, including antioxidant,
prebiotic, immunomodulatory, and other health-related effects, is examined in the context of functional
food design, safety assessment, and novel food regulatory pathways. By integrating physicochemical, technological,
and regulatory perspectives, this review identifies key research gaps and outlines priority directions
needed to position microalgal EPSs as sustainable, clean-label hydrocolloids for future food systems.