Kinetics of solid-liquid extraction of anthocyanins obtained from Hibiscus rosa-sinensis

Abstract

This study analyzes the solid-liquid extraction kinetic of anthocyanins from Hibiscus rosa-sinensis. The effects of temperature, solvent polarity using water (H2O)-ethanol (EtaOH) solutions, and solvent-to-solid ratio on the mass transfer rate and the anthocyanin extraction yield were evaluated. The experimental data were fitted to Spiro and Siddique model with a good accuracy (r2 ≥ 95:68%) and the specific extraction rate constant was perfectly related to the apparent diffusivity using the lumped parameter model. The apparent diffusivity was more sensitive to temperature changes as the solvent polarity decreased. The major percentage of the anthocyanin extraction yield was 63.81±1.33, 68.95±1.53, and 83.09±3.14 when the used solvent was H2O, H2O-EtaOH (90:10% v/v), and H2O-EtaOH (80:20% v/v), respectively, at highest conditions of the temperature (60 ºC) and the solvent-to-solid ratio (80/1 mL/g). Finally, the anthocyanin extraction yield was successfully related to experimental extraction conditions using response surface methodology.