Modulating glycaemic response in steamed buns with chitosan: effects on bun properties and starch digestibility

Chitosan (CS) is a natural polysaccharide known for its antioxidant, antimicrobial, and non-toxic properties, and has been reported to lower blood glucose levels when orally administered prior to meals. Although widely utilized in industrial and biomedical contexts, its application in the development of low glycaemic index (GI) foods remains relatively unexplored. This study evaluates the potential of CS as a functional additive to reduce starch digestibility in starch-rich foods, using steamed buns as a model system. Incorporation of CS at 200 g/kg significantly reduced the area under the curve (AUC) of postprandial blood glucose response in participants consuming the CS-enriched bun (673.75 ± 101.7 mmol/L) compared to the control (747.0 ± 101.4 mmol/L). Sensory evaluation revealed modest declines in texture and taste scores; however, overall acceptability remained relatively high (5.7 ± 1.5 vs. 6.7 ± 1.6). CS addition also led to reductions in specific volume and fermented dough size, though SDS-PAGE analysis indicated no significant changes in gluten formation. Together with observed decreases in the hydrolysis index and estimated glycaemic index, these findings suggest that CS can effectively reduce starch digestibility while maintaining acceptable sensory quality in starch-rich food products.