Preparative purification of rebaudioside A from aqueous extracts using chromatography: a process idea

An innovative chromatographic process idea for preparative purification of rebaudioside A from aqueous extracts of Stevia rebaudiana Bertoni leaves is developed. The process can handle high concentrated aqueous extracts, needs less equipment and has a lower solvent consumption compared to the state-of-the-art purification process of rebaudioside A. The innovative process consists of a cascade of three preparative chromatographic columns. The first column separates steviol glycosides from the plant matrix using water as eluent in reversed phase mode. The fraction of steviol glycosides is then concentrated on a second column which works as a capture column with a more non-polar adsorbent. The last column separates rebaudioside A from steviol glycoside under normal phase conditions using a mixture of acetonitrile and water as eluent. With a total yield of 97.5 ± 1.5 % and a purity of 97.1 ± 1.5 % the process fulfills the legal requirements for the purity of rebaudioside A.