Insights into the copigmentation effect and mechanism of five carbohydrates on thermal and color stability of mulberry anthocyanins

The copigmentation effects and underlying mechanisms of β-cyclodextrin (β-CD), chitosan (CS), guar gum (GG), xanthan gum (XG), and β-glucan (β-GC) on the stability of mulberry anthocyanins (MAS) were systematically investigated. β-CD exhibited the strongest protective effect, followed by CS and β-GC. At 60 °C, β-CD extended the half-life of MAS from 7.42 h to 11.54 h, and significantly reduced the total color difference (ΔE*) value. Molecular docking indicated that β-CD and CS formed stable complexes with cyanidin-3-glucoside (C3G, main monomer in MAS) through the synergistic action of hydrogen bonding, electrostatic interactions, and hydrophobic interaction with high binding free energy. Whereas β-GC, GG, and XG mainly interacted via weak hydrogen bonding. FTIR spectroscopy revealed that β-CD and CS interacted with the C3G hydroxyl and amino vibration groups. Particle size distribution and zeta potential analysis further confirmed that β-CD protected C3G primarily through structural complementarity and inclusion complexation, while CS mainly via electrostatic stabilization.