Enhancement of encapsulation efficiency and in vitro bioaccessibility of spray-dried curcumin microcapsules by selected bio-coating materials

Abstract

The encapsulation of curcumin in combination with spray drying is one of the techniques capable of improving its stability. This process is highly dependent on coating material. Natural biopolymers, such as maltodextrin (MD) and gum Arabic (GA), have been reported to show curcumin protection as coating material. Konjac glucomannan hydrolysate (KGMH) is a functional food ingredient with potential as a coating material. Applying the combination of these biopolymers to encapsulate curcumin should improve the properties of microcapsules. This study investigated the effects of combining coating materials (KGMH, MD, and GA) on bioaccessibility and encapsulation efficiency (EE) of spray-dried curcumin microcapsules. The initial emulsion (mean particle size, polydispersion index, ζ-potential, and viscosity) and microcapsule (yield, water activity, moisture content, color, solubility, hygroscopicity, size, morphology, Fourier-transform infrared (FT-IR) spectra, and antioxidant activity) properties were also characterized. Each coating material contributed to both the advantages and disadvantages characters of the microcapsules. The higher binding of surface-active GA generated a higher EE but lower bioaccessibility. The opposite trend was observed in MD-coated microcapsules. KGMH and MD provided comparable bioaccessibility, but the higher EE of KGMH was evidenced. All coating materials produced curcumin microcapsules with statistically equal ferric-reducing antioxidant power. The combined MD, GA, and KGMH in a similar ratio was the best formulation that produced microcapsules with a good bioaccessibility (78.83%) and EE (85.52%) profile.

Practical Application

This study on curcumin encapsulation could benefit the nutraceutical and functional food industry by creating stable, bioaccessible curcumin supplements with enhanced antioxidant properties. Using a blend of natural coating materials, such as konjac glucomannan hydrolysate, maltodextrin, and gum Arabic, these microcapsules could improve curcumin's effectiveness in health products, potentially increasing consumer access to curcumin's health benefits in a stable, easy-to-use form.