Method for the recovery of steviosides from plant raw material

A method for recovering steviosides from dried plant material of Stevia rebaudiana Bertoni, comprising treating dried plant material of Stevia rebaudiana Bertoni by stirring in a solvent consisting of water at a temperature ranging from room temperature to about 65.degree. C., filtering or centrifuging the treated plant material to obtain an aqueous extract, treating the aqueous extract with a salt selected from the group consisting of calcium oxide, calcium carbonate and other basic calcium salts to form a precipitate, filtering and centrifuging the treated extract to separate the precipitate, sequentially treating the separated precipitates three times, first with a strongly acidic ion exchange resin and then with a weakly basic ion exchange resin, and thereafter filtering and drying the treated precipitate to obtain a product containing steviosides without employing any solvents other than water.

A method of recovering steviosides from dried plant material of Stevia rebaudiana Bertoni, comprising treating dried plant material of Stevia rebaudiana Bertoni by stirring in a solvent consisting of water at a temperature ranging from room temperature to about 65.degree. C., filtering or centrifuging the treated plant material to obtain an aqueous extract, treating the aqueous extract with a salt selected from the group consisting of basic magnesium salts and basic aluminum salts to form a precipitate, filtering and centrifuging the treated extract to separate the precipitate, sequentially treating the separated precipitate three times, first with a strongly acidic ion exchange resin and then with a weakly basic ion exchange resin, and thereafter filtering and drying the treated precipitate to obtain a product containing steviosides without employing any solvents other than water.