Encapsulation of curcumin loaded oil droplets with chitosan based cryogel: Influence of freezing condition on nanocapsule properties

Abstract

Encapsulation of curcumin-loaded oil droplets with chitosan-based cryogels, made from a ternary system of colloidal chitosan, κ-carrageenan, and carboxymethylcellulose (CMC) sodium salt, was carried out and the effects of the freezing condition (unidirectional freezing rate with and without post-freezing incubation) and the initial concentration ratio of carrageenan to CMC on the properties of the cryogel nanocapsules were experimentally investigated. Both the freezing condition and initial concentration ratio had significant effects on the gel fraction yield, swelling extent, particle size and zeta potential, as well as the curcumin release pattern. Specimen I-S1-02, which was made of polymer set 1 (carrageenan:CMC = 4:6) at a rapid freezing rate of -2°C/min with 10-hr incubation at -10°C, showed the slowest release rate (first-order type) of curcumin. In comparison, it was found that microcapsules obtained by spray-drying a similar O/W curcumin emulsion with dextran as stabilizer exhibited the fastest rate of curcumin release, similar to a burst release.