Precipitation of Curcuminoids from Hydrotrope Solution: Crystal Nucleation and Growth Kinetics from Batch Experiments

Abstract

Precipitation kinetics of curcuminoids from aqueous hydrotropic solutions of sodium cumene sulfonate was investigated in a laboratory‐scale agitated vessel using acidic water (pH 3) as a precipitant. The time evolution of the crystal size distribution was used to deduce simultaneously the crystal growth kinetics. The transient population density curves were measured by a Coulter counter light scattering unit. The kinetic data from the experimental runs were correlated by a power law relative kinetic expression. Crystallization experiments using hydrotropic extracts of turmeric were also performed to compare the results with pure curcuminoids in the hydrotrope solutions. The results indicate slow crystal growth and thus formation of very fine crystals of curcuminoids in the range of 1 to 100 µm.