Botryosphaeran β-glucan: Structure–activity and functional food challenges, functional food applications and biotechnological potential

Botryosphaeran is a water-soluble extracellular β-(1→3;1→6)-D-glucan exopolysaccharide (EPS) produced by Botryosphaeria rhodina strain; extensively characterized preparations used in the literature display ∼98% glucose content and high molecular weight. This critical review synthesizes botryosphaeran’s physicochemical properties, structural features, and preclinical bioactivities. In rodent models, representative efficacies include blood glucose reductions of up to 52% and low-density lipoprotein (LDL) cholesterol decreases of ∼27%, supporting its metabolic regulatory potential alongside reported antioxidant and immunomodulatory effects. We organize biological functions in the sequence presented in the main text: metabolic regulation, immune and antitumor activities, and gut-health enhancement via prebiotic effects. Technological applications surveyed include its use as a stabilizer and thickening agent in functional foods, as a microencapsulation matrix for bioactive compounds, and as an enzyme-immobilization matrix for biosensor development. Major translational bottlenecks remain: limited large-scale fermentation yields, batch-to-batch structural heterogeneity, incomplete elucidation of underlying molecular mechanisms, and a paucity of human clinical trials. Compared with cereal, yeast, and mushroom β-glucans, botryosphaeran’s highly branched β-(1→3;1→6) architecture, higher average molecular weight, and stable triple-helical conformation likely underlie its distinct rheological properties and broader bioactivity profile. Based on evidence from fermentation science, structural biology, and immunology, botryosphaeran is a promising candidate for development as a functional food ingredient and nutraceutical for managing cardiometabolic disorders, inflammation, and immune dysregulation, provided scale-up and translational challenges are addressed.