Lutein-Loaded Emulsions Stabilized by Egg White Protein-Dextran-Catechin Conjugates: Cytotoxicity, Stability, and Bioaccessibility

The aim of this study was to investigate the cytotoxicity, physicochemical stability, and bioaccessibility of lutein-loaded emulsions stabilized by egg white protein-dextran-catechin (EWP-Dex-EC) conjugates. The conjugates were developed using a two-step method involving free radical grafting combined with the Maillard reaction. Cytotoxicity analysis indicated that the conjugates were nontoxic and biocompatible. Changes in particle size, zeta-potential and lutein retention of the emulsions were determined to evaluate their physicochemical stability. Grafting dextran to the egg white protein improve the physical stability of the emulsions, which was attributed to an increase in steric repulsion between the protein-coated oil droplets. The attachment of catechin to the egg white proteins increased their interfacial antioxidant activity, which inhibited lutein degradation in the emulsions. The highest bioaccessibility of lutein was observed in the EWP-Dex-EC conjugate-stabilized emulsions, which was mainly attributed to the relatively smaller droplet size and stronger antioxidant activity. Our results suggest that the protein-polysaccharide-polyphenol conjugates formed in this study could be used as antioxidant emulsifiers to improve the physicochemical stability and bioavailability of lipophilic bioactives.

Automated summary

The cytotoxicity, physicochemical stability, and bioaccessibility of lutein-loaded emulsions stabilized by egg white protein-dextran-catechin (EWP-Dex-EC) conjugates were investigated in this study. The conjugates were found to be non-toxic and biocompatible. Grafting dextran to the egg white protein improved the physical stability of the emulsions, while the attachment of catechin increased their interfacial antioxidant activity. The EWP-Dex-EC conjugate-stabilized emulsions showed the highest bioaccessibility of lutein, which was attributed to their smaller droplet size and stronger antioxidant activity.