An economic and eco-friendly method for the recovery of ellagic acid from waste pomegranate peel via thermal hydrolysis assisted extraction and liquid-liquid extraction

In the present study, a low-cost and environmentally-friendly method for the recovery of ellagic acid (EA) from waste pomegranate peel (WPP) was developed. Thermal hydrolysis assisted extraction (THAE) method was designed to efficiently prepare EA at low economic and environmental costs by the simultaneous extraction and hydrolysis of EA and its derivatives using NaH 2 PO 4 solution as extraction solvent, which could be reused at least 5 times after simple post-treatments. Ethyl acetate was chosen as liquid-liquid extraction (LLE) solvent to directly recover EA from THAE extract and regenerate NaH 2 PO 4 solution. After a series of optimization of operation parameters, the recovery rates of EA in the THAE and LLE processes reached ∼94% and 96%, respectively. As all of the solvents used above belong to cheap, eco-friendly, and edible solvents, this proposed method provides a good way to get safe and inexpensive EA-rich extract (with a purity of ∼89%), which could be used as natural ingredient in food, cosmetic, and medicinal industries, as well as starting materials for the preparation of pure EA.