A novel process for extraction of natural sweetener from licorice (Glycyrrhiza glabra) roots

Pressurized hot water extraction (PHWE) is a very useful technique for recovering bioactive molecules from natural materials using subcritical compressed liquid water in the temperature range of 50–150 °C. A novel process has been developed for making a natural sweetener from licorice (Glycyrrhiza glabra) roots involving selective chemical reaction and easy separation, for recovering mono-ammonium glycyrrhizate (MAG) using hot water with dissolved ammonia and pressurized with carbon dioxide. The performance of the novel PHWE process has been evaluated to ascertain the optimum process parameters to maximize the recovery of MAG by varying the parameters, such as temperature (30–120 °C), pressure (1–10 atm), extraction time (60–120 min), water-to-feed ratio (20–40 ml/g), number of stages (1–3), stirring rate (0–350 rpm), ammonia concentration (0.01–4%, w/v), and grinding. The quantification of MAG recovered in the extract has been based on the vanillin sulfuric acid method using UV spectrophotometer. The maximum recovery of MAG from licorice roots has been achieved at 110 °C and 5 atm with the ratio of 40 ml/g of 0.01% (w/v) ammonia solution to powdered feed after 90 min of extraction.