Non-covalent assembly of chicory inulin and casein for the stabilization of blueberry anthocyanins: structural characterization, interaction mechanism and antioxidant activity

Abstract

This study investigated the protective effects of chicory inulin (CI) and casein (CN) on blueberry anthocyanins (ACNs) and examined interactions within the ternary system. Stability was evaluated under thermal, formulation, storage, pH, in vitro digestion, and acidified model-beverage conditions, together with multispectral characterization and molecular docking. Fluorescence measurements showed that quenching depended on ACNs concentration. FTIR and CD spectra revealed changes in the secondary structure of CN after complexation. Molecular docking suggested possible binding modes. Hydrogen bonding and hydrophobic contacts may help ACNs associate with the CI-CN complex. Under the tested model conditions, CI-CN complexes improved ACNs retention. They also gave higher values in radical scavenging and reducing capacity assays, especially at higher CI concentration. These results support further work on CI-CN complexes as anthocyanin carriers. These findings provide a mechanistic basis for further evaluating CI-CN complexes in anthocyanin-containing food systems.