Enhancing the stability of synthesized curcumin by spray-drying microencapsulation with soy lecithin and gum Arabic

Curcumin is a phytochemical with many beneficial biological activities, but the low solubility, stability and bioavailability have restricted its application range. To enhance curcumin stability, we microencapsulated curcumin by spray-drying together with soy lecithin as the core material and gum Arabic as the shell material. SEM images showed that the spray-dried microcapsules were irregular in shape and 4.3 ± 2.0 µm (mean ± standard deviation) in size. Results of Fourier transform infrared spectroscopy and differential scanning calorimetry exhibited intermolecular interactions between components in the microcapsules. X-ray diffraction patterns revealed the amorphous character of the microcapsules, which explained their high solubility in water. Increasing the shell/core mass ratio from 1:1 to 3:1 significantly improved not only the encapsulation efficiency of curcumin, but also the stability of the encapsulated curcumin toward light, high temperature, and neutral—basic pH conditions. However, increasing the shell/core ratio from 3:1 to 5:1 did not yield significant improvements in encapsulation efficiency, solubility and stability of curcumin. At 70 °C, curcumin in the microcapsules was stable for all studied core:shell ratios, suggesting an interaction between curcumin and gum arabic that blocks the degradation mechanism of curcumin. This study showed that microencapsulation using gum arabic as a wall material can be implemented to protect curcumin from adverse conditions, thus promoting its applicability in the food and the pharmaceutical industries.