OSA-modified bacterial cellulose microgels: Synthesis, characterization, and hydrophobic bioactive delivery

This study presents the synthesis and characterization of octenyl succinic anhydride (OSA)-modified bacterial cellulose (OBCs) with varying degrees of substitution (DS). Structural analyses confirmed successful OSA grafting onto BC, with higher DS enhancing amphiphilicity, indicated by a contact angle of 83.64° ± 1.26 and excellent colloidal stability (zeta potential < -30 mV). OBC-based microgels were prepared through crosslinking with hyaluronic acid (HA), achieving high encapsulation efficiency for astaxanthin (AST). The AST-loaded microgels demonstrated significantly improved storage stability, retaining over 85 % AST after 28 days at 4 °C, reducing oxidative degradation while preserving AST's antioxidant activity. Incorporating AST-loaded OBC-HA microgels into yogurt enhanced its antioxidant capacity and improved physical properties by increasing texture firmness and water-holding capacity while minimizing whey separation. These findings indicate that OBC-HA microgels effectively protect hydrophobic bioactives, serving as stabilizers and carriers for hydrophobic nutraceuticals in functional foods like yogurt, thereby enhancing nutritional value and texture.