Catechin modulates the copigmentation and encapsulation of anthocyanins in polyelectrolyte complexes (PECs) for natural colorant stabilization.

Our objective was to develop a robust system for anthocyanin-based color intensification, with high-encapsulation capacity and improved stability of the encapsulated natural colorant. Catechin was used to modulate the copigmentation and encapsulation of anthocyanins in counter-ionic polyelectrolyte complexes (PECs) composed of chondroitin sulfate and chitosan. Results showed that catechin copigmentation significantly intensified red color of formulations both with and without encapsulation in PECs and improved the anthocyanin encapsulation efficiency by forming additional dense network through hydrogen bonding. A series of stability assays revealed that anthocyanin stabilizing effect of system depended on the formulated pH and adding order of catechin. The strongest retaining capacity of anthocyanin was observed when catechin was copigmented with anthocyanin directly in PECs at pH 3.3, while the coated layer of catechin covered on PECs would be more effective at pH 4.0 and 5.0. Furthermore, we demonstrated that this delivery system works for anthocyanins from different sources.