Encapsulation of Epigallocatechin-3-gallate (EGCG) Using Oil-in-Water (O/W) Submicrometer Emulsions Stabilized by iota-Carrageenan and beta-Lactoglobulin

Abstract

Oil-in-water (O/W) submicrometer emulsions stabilized by iota-carrageenan and beta-lactoglobulin were successfully prepared by high-pressure homogenization (HPH), with the goal to develop biocom-patible carriers for the active component of green tea, epigallocatechin-3-gallate (EGCG) The effects of pressure and the number of cycles on the physical properties of emulsions, such as droplet sizes, microstructure, and rheological properties were investigated. The increase in both processing pressure and the number of HPH cycles resulted in a decrease in droplet sizes and viscosities A submicrometer O/W emulsion with a droplet size of about 400 nm was used to encapsulate EGCG The results showed that, when EGCG concentration was up to 0 5% in the emulsion, EGCG could be successfully encapsulated in the O/W emulsions stabilized by iota-carrageenan and beta-lactoglobulin Within 14 days, emulsion droplet sizes showed negligible changes However, when EGCG concentration was >0 5%, significant instability of the O/W emulsions due to the binding between EGCG and beta-lactoglobulin was observed, as evidenced by the largely increased droplet sizes from light scattering and the appearance of large aggregates in the optical images Moreover, EGCG encapsulated in an O/W submicrometer emulsion revealed art enhanced in vitro anticancer activity compared to the free EGCG This study provides a novel encapsulation formulation to increase the biological efficacy of EGCG