Formation, characterization, and application of chitosan/pectin-stabilized multilayer emulsions as astaxanthin delivery systems

Multilayer emulsions were formed by sequential electrostatic deposition of anionic (pectin) and cationic (chitosan) biopolymers onto anionic saponin-coated lipid droplets. These emulsions were then tested for their ability to encapsulate and protect a hydrophobic nutraceutical (astaxanthin). The impact of chitosan and pectin concentration, pH, and ionic strength on the formation and stability of the multilayer emulsions was examined. Multilayer emulsions containing small uniform particles were produced using 2.5% lipid droplets, 0.05% chitosan, and 0.0125% pectin. The physical stability of the astaxanthin-loaded emulsions after exposure to heating, pH, and NaCl was determined. The multilayer-coatings improved the chemical stability of the encapsulated astaxanthin, as well as the aggregation stability of the lipid droplets at elevated ionic strengths and temperatures. Astaxanthin degradation during storage was 3- to 4-fold slower in multilayer emulsions than conventional ones. The multilayer emulsions developed in this study may be useful for encapsulating, protecting, and delivering hydrophobic carotenoids, which may aid in the development of more efficacious functional foods, supplements, and medical foods.