Kinetic and Thermodynamic Analysis for the Ultrasonic-Circulating Extraction of Alkaloids from Lepidium meyenii Walp.（Maca）

Abstract:

This study investigated kinetics and thermodynamics for the ultrasonic-circulating extraction of Lepidium meyenii Walp.（maca） alkaloids. The extraction was carried out with different temperatures or acoustic energy densities. Two site model was applied to simulate the extraction kinetics and Van't Hoff equation was used to calculate thermodynamic parameters. Results showed that two site model gave satisfactory data fit. Alkaloid yield and rate constants were enhanced with increased temperature or acoustic energy density. The activation energy values were 16.41 kJ/mol and 17.52 kJ/mol for washing and diffusion stages，respectively. The alkaloid extraction was endothermic，irreversible and spontaneous. In addition，compared with maceration，ultrasonic- circulating extraction resulted in significantly higher yields of alkaloids at 20 ℃ and 50 ℃（p<0.01）. Therefore，ultrasonic-circulating extraction is an effective technology to extract maca alkaloids.