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US 5,972,120 AGranted
Extraction of sweet compounds from Stevia rebaudiana Bertoni
AssigneeNational Research Council of Canada
InventorsOleh Kutowy, Shi Qiu Zhang, Ashwani Kumar
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Abstract
The invention disclosed relates to a process for the extraction of sweet compounds from Stevia rebaudiana Bertoni, by column extraction, followed by purification by filtration. The extraction is at temperatures in the range of 0 to 25.degree. C. Preferably, a pre-treatment step of microfiltration is used to clarify the extract. Purification is by ultrafiltration followed by nanofiltration. The filtration conditions are controlled to optimize the recovery of the sweet compounds.
Claims20
A process for the extraction of sweet compounds from Stevia rebaudiana Bertoni, comprising
- (a) providing an extraction column, the column being vertically disposed and having a top opening for receiving plant material and extraction solvent, and a bottom opening for discharging extract,
- (b) adding substantially dry Stevia plant material to the column to form a bed,
- (c) adding an aqueous extraction solvent at a temperature of 0 to 25.degree. C. to the column, to provide a controlled plant material:
- solvent ratio in the range of 0.02:1 to 0.1:1 w/w,
- (d) removing from the column an extract including the sweet compounds,
- (e) passing the extract through an ultrafiltration membrane having a pore size defined by a molecular weight cut-off (mwco) of 2 to 3 k Da, at a trans-membrane pressure of 200 to 700 kPa,
- (f) passing the permeate including the sweet compounds, at a controlled temperature in the range of 50 to 85.degree. C. through a high temperature nanofiltration membrane having a pore size defined by a molecular weight cut-off of 200 to 600 Da, at a trans-membrane pressure of 600 to 1300 kPa, and
- (g) recovering the retentate including the sweet compounds.
5 more elements
Dependencies are inferred from the claim text.