Solid–liquid extraction of anthocyanins from calyces of Hibiscus sabdariffa L.
was studied to evaluate the influence of the operating parameters.
Solid-to-solvent ratio and particle size had the main impact on anthocyanin extraction efficiency.
Maximum yield of anthocyanins (88%) was obtained at 25 C with the highest solid-to-solvent ratio (1/25). The decrease in the particle size of the calyces from 2 cm to
150 lm drastically reduced the extraction time.
The increase of temperature reduced the extraction time by increasing the diffusion coefficient (3.9 1011–1.35 1010 m2 s1 between 25 and 90 C) but did not modify the extraction yield.
A simple extraction model that integrated anthocyanin thermo-degradation kinetic was proposed.
A good agreement between the predicted results of the models and experimental data was demonstrated.
From a solid-to-solvent ratio of 1/5, an extraction yield of 63% and an anthocyanin concentration of 0.3 g L1 could be obtained in less than 10 min.