Dynamic liquid film crystallization (DLFC): An additive-free strategy for spherical curcumin particles with superior powder flowability for functional foods.

Curcumin's application in functional foods is hindered by poor aqueous solubility, low bioavailability, and irregular particle aggregation. Existing strategies often compromise food safety with additives or require harsh processing. Herein, a novel dynamic liquid film crystallization (DLFC) method was developed for green, additive-free fabrication of relatively monodisperse, spherical curcumin particles. By regulating initial concentration, bead diameter, and cyclic processing, DLFC enabled two growth-dominated pathways yielding smooth (1004 nm) and rough spherical particles. X-ray diffraction confirmed the formation of metastable Form II, distinct from raw curcumin's Form I, accompanied by a reddish hue. DLFC particles exhibited superior powder properties (bulk density 0.55 g/cm3, angle of repose 32.8°), enhancing solubility and processability. Compared to reported techniques, DLFC features ambient pressure/temperature operation, facile tunability and scalability. This additive-free and efficient method addresses curcumin's bioavailability challenge, providing a promising route for its valorization as a high-performance functional food ingredient and pharmaceutical formulation.