Abstract:

Ultra high pressure treatment was used to assist the ethanol extraction of glycyrrhizic acid from Glycyrrhiza uralensis roots at normal temperature. The effects of extraction time, ethanol concentration, pressure and liquid/solid ratio on extraction yield of glycyrrhizic acid were analyzed using single-factor experiments. Response surface methodology (RSM) based on a three-level, three-variable central composite rotatable design (CCRD) was employed to optimize three crucial variables except extraction time. The optimum extraction conditions were determined as follows: ethanol concentration 49.50%, liquid/solid ratio 13:1, extraction pressure 382 MPa for an extraction duration of 15 min. Under the optimized conditions, a extraction yield of glycyrrhizic acid of 14.61％ was predicted, and the average value of 5 repeated experiments was14.67 %, with a relative standard deviation of 0.29 %.

Key words: Glycyrrhiza uralensis, glycyrrhizic acid, ultra high pressure-assisted extraction, response surface methodology