Coacervation-based co-encapsulation of curcumin and vitamin E in gelatine-alginate microcapsules: a comprehensive study on encapsulation efficiency, physical properties, structure and release behaviour.

Abstract

Curcumin and α-tocopherol (vitamin E) are lipophilic antioxidants limited by poor stability. To overcome this, both compounds were co-encapsulated in tannic acid-crosslinked gelatine-sodium alginate microcapsules via complex coacervation, comparing Ultra-Turrax (UT) and ultrasonication (US) homogenisation across core-to-wall ratios (1/1, 1/2, 1/3). Ultrasonication at a 1/3 ratio yielded the highest encapsulation efficiencies (94.3% curcumin, 91.0% vitamin E, vs. ∼41-44% untreated). These US microcapsules were smaller (227 nm), less porous (36.7%), and demonstrated progressive pH-dependent release over 72 h without an initial burst. Antioxidant activity was fully retained during simulated gastrointestinal digestion. Overall, ultrasonication-assisted complex coacervation provides an effective route for developing robust gelatine-alginate delivery systems for food and pharmaceutical formulations.