Purification of steviosides by membrane and ion exchange processes

An ultrafiltration (UF) process removed more than 96% of the pigments and recovered 45% of steviosides non-nutritive sweetener from an extract of leaves, UF retentate was further processed by diafiltration (DF), and the permeate was concentrated by reverse osmosis (RO). The membrane processes (UF, DF, RO) achieved an overall steviosides recovery of more than 90% with product purity 46%. Final purification was conducted by two consecutive mixed bed ion exchange processes. The ion exchangers improved purity of the final product to 90%.