DFT study of the stabilization effect on anthocyanins via secondary interactions

Abstract

Anthocyanins, which are the labile flavonoid pigments in botanical food, are attracting intensive attention because they can reduce the risk of noncommunicable diseases. Thus, many dietary molecules have been explored to minimize anthocyanin degradation. This study developed a novel model based on the density functional theory (DFT) and conceptual density functional theory (CDFT) to screen small dietary compounds that can stabilize aqueous anthocyanins. The progression of anthocyanin degradation, which was modeled as an aqueous food system, was illustrated using thermodynamic computation and relaxed scanning. The nucleophilic index and dipole moment were applied to quantify van der Waals interaction between anthocyanins and stabilizers. Two equations based on first-order kinetics were established to demonstrate that the equilibrium constant and free energy of the binding reaction between anthocyanins and stabilizers were theoretically important. The change in binding free energy change (ΔG) may be the best indicator of the protection offered by dietary stabilizers on anthocyanins, which was demonstrated by comparisons of computational ΔG with the thermal half time from the previous study on the effects of gallic/ferulic/caffeic acids on anthocyanin stability. Based on established forecasting methods, trans-resveratrol (ΔG = −35.63 kJ/mol) was found to be the best stabilizer among dietary compounds.

Keywords

• Anthocyanin
• Quantum chemistry
• Conceptual density functional theory
• Secondary interactions
• Degradation