Development of multi-stage countercurrent extraction technology for the extraction of glycyrrhizic acid (GA) from licorice (Glycyrrhiza uralensis Fisch)

Multi-stage countercurrent extraction (MCE) technique has been developed for the extraction of glycyrrhizic acid (GA) from Glycyrrhiza 14 uralensis Fisch, a particular plant species of licorice. The effects of extraction stage numbers, temperature, extraction time and solvent to licorice ratio on the extraction yield of GA were investigated in detail. The process conditions of MCE were optimized using orthogonal array experimental design (OAD) technique. Under optimum process conditions (five stages, 60 min extracting time for every stage, 60 degreesC temperature and 6 ml/g solvent to licorice ratio), the extraction efficiency of MCE has been compared with those of conventional techniques including batch single pot extraction (SPE), microwave-assisted extraction (MAE), ultrasonic extraction (USE), Soxhlet extraction (SHE) and room temperature extraction (RTE). Results show that the MCE process offers the highest GA extraction yield and considerable savings in time, energy and solvent consumption. (C) 2004 Elsevier B.V. All rights reserved.