Dietary Microbial Polysaccharides in Food Systems: Production, Functional Properties, and Applications

Microbial polysaccharides are structurally diverse biopolymers produced by bacteria, fungi, yeasts, and algae, functioning as extracellular matrices and/or intracellular carbon reserves depending on the organism and growth conditions. Among them, microbial exopolysaccharides (EPSs) have attracted substantial interest because their tunable architectures confer desirable techno-functional attributes alongside emerging biofunctional potential. This review synthesizes recent advances in EPS research with emphasis on how microbial origin, biosynthetic routes, and glycosidic linkage patterns shape higher-order structure and, ultimately, functional performance in food systems. We summarize major EPS classes and representative producing microorganisms, outline key structure-property relationships relevant to formulation and processing, and critically discuss reported biological activities in the context of evidentiary strength and translational relevance. In addition, we compare current production, recovery, and purification strategies, highlighting practical considerations for scalability, product consistency, and regulatory compliance. Finally, we identify opportunities and bottlenecks for next-generation dietary EPSs, including precision fermentation, strain engineering, and application-driven design to meet clean-label and sustainability goals. Collectively, this review provides a framework for rational selection and development of microbial EPSs as functional ingredients for food innovation.