Designing Curcumin Particles with Improved Bioactivity and Bioavailability Using Aerogels and Supercritical Fluid Technology

Health benefits of curcumin (CUR) are widely acknowledged; however, its full potential remains untapped due to its limited bioavailability. Curcumin's high crystallinity and poor water solubility markedly limit its bioavailability. Therefore, there is a critical need for a method that decreases the crystallinity of CUR. This study aimed at increasing the bioavailability of CUR by forming first-of-its-kind low-crystallinity curcumin particles using nanoporous starch aerogels and supercritical carbon dioxide (SC-CO₂). The formation of CUR-NP relied on the starch aerogel's nanopores and large surface area, which, combined with SC-CO₂, reduced the size and crystallinity of CUR by controlling its recrystallization process. The results showed that this method was notably effective in decreasing the crystallinity of curcumin, where a higher impregnation temperature caused curcumin-impregnated aerogels with lower curcumin crystallinity and more homogeneous curcumin distribution into aerogels. The fluorescence studies suggested that curcumin was entrapped in the hydrophobic cavities in the backbone of starch aerogels. Curcumin-impregnated aerogels exhibited significantly increased antioxidant activity in aqueous media. Moreover, in vitro gastrointestinal digest experiments revealed ∼30 times higher bioaccessibility for curcumin impregnated at 120 °C compared to that of native curcumin. While native curcumin showed an untraceable intestinal cell transportation measured by the Caco-2 cell line, curcumin-impregnated aerogels prepared at an impregnation temperature of 120 °C demonstrated a total curcumin passing of 0.86 μg/mL. The optimal SC-CO₂-assisted impregnation condition for curcumin crystallinity and bioavailability was determined to be an impregnation temperature of 120 °C and a curcumin-to-aerogel ratio of 1 to 9. Due to the high antioxidant activity and enhanced bioavailability of the curcumin impregnated in the edible starch aerogels, they can serve as functional food ingredients for health-promoting functional foods and supplements.