Enhanced Dispersibility and Bioactivity of Curcumin by Encapsulation in Casein Nanocapsules

TLDR

This simple spray‑drying approach can encapsulate various lipophilic bioactive compounds. The study aimed to develop a novel spray‑drying encapsulation method using sodium caseinate and curcumin as a model compound. The method involved spray‑drying a warm aqueous ethanol solution containing sodium caseinate and curcumin, then hydrating and centrifuging the powder to produce curcumin‑loaded casein nanoparticles. Encapsulation removed curcumin crystallinity, increased its aqueous dispersibility by four orders of magnitude, produced nanoparticles larger than native NaCas but smaller than processed NaCas, and improved antioxidant and cell‑proliferation activity relative to free curcumin.

Abstract

In this work, a novel encapsulation method was studied by spray-drying a warm aqueous ethanol solution with codissolved sodium caseinate (NaCas) and lipophilic food components, using curcumin as a model compound. The encapsulation caused the loss of crystallinity of curcumin. After hydration of spray-dried powder and centrifugation, 137 μg/mL curcumin was dispersed in the transparent dispersion, which was 4 decades higher than its water solubility. Dynamic light scattering and atomic force microscopy results showed that curcumin-loaded casein nanoparticles were bigger than those of NaCas processed at encapsulation conditions but were smaller than those of the native NaCas. The increased nanoparticle dimension, together with fluorescence and FTIR spectroscopy results, suggested that curcumin was entrapped in the nanoparticle core through hydrophobic interactions. The curcumin encapsulated in casein nanoparticles had higher biological activity, as assessed by antioxidant and cell proliferation assays, than pristine curcumin, likely due to the improved dispersibility. This simple approach may be applied to encapsulate various lipophilic bioactive compounds.