Impact of chitosan-EGCG conjugates on physicochemical stability of β-carotene emulsion

The aim of the present study was to investigate the effects of low-molecular-weight chitosan (LC)-(-)-epigallocatechin-3-gallate (EGCG) conjugates on the physicochemical properties of oil-in-water emulsions incorporating beta-carotene within the oil droplets. Covalent coupling of LC to EGCG was achieved by hydroxyl-free radical grafting. The physicochemical stability of beta-carotene emulsions was characterized by droplet size and distribution, rheological behavior, transmission profiles using novel centrifugal sedimentation and beta-carotene degradation in the emulsion during storage. beta-Carotene emulsions stabilized by LC-EGCG conjugates had relatively smaller mean droplet size, more homogenous droplet size distribution and less change in centrifugal transmission profiles, indicating a substantial improvement in physical stability. Degradation of beta-carotene in emulsions during storage was significantly retarded by LC-EGCG conjugates than native LC (formed without the redox pair and without EGCG) and control LC (formed with redox pair and without EGCG). These results implied that LC-EGCG conjugates were able to improve the physical stability of beta-carotene emulsion and inhibit the deterioration of beta-carotene in oil-in-water emulsions. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.