High-purity steviol glycosides

Abstract

Methods of preparing highly purified steviol glycosides, particularly Rebaudioside D, are described. The methods include purification from the extraction stage of the Stevia rebaudiana Bertoni plant, purification of steviol glycoside mixtures, Rebaudioside D and Rebaudioside A from a commercial Stevia extract, and purification of Rebaudioside D from remaining solutions obtained after isolation and purification of Rebaudioside A and a high purity mixture of steviol glycosides. The methods are useful for producing high purity Rebaudioside D, Rebaudioside A, and steviol glycoside mixtures. The high purity steviol glycosides are useful as non-caloric sweeteners in edible and chewable compositions such as any beverages, confectioneries, bakery products, cookies, and chewing gums.

1 .- 27 . (canceled) 
     
     
         28 . A purified steviol glycoside mixture having a purity level of at least about 95% (w/w) on a dry basis made by a method comprising the steps of:
 a. providing a solution comprising steviol glycosides;   b. providing a plurality of consecutively connected columns packed with an adsorbent resin capable of adsorbing steviol glycosides to create a multi-column system;   c. passing the solution of steviol glycosides through the multi-column system to obtain at least two columns, each column having a different ratio of adsorbed steviol glycosides; and   d. eluting the adsorbed steviol glycosides from at least one column in the multi-column system, to obtain an eluted Solution comprising the purified steviol glycoside mixture having a purity level of at least about 95% (w/w) on a dry basis.   
     
     
         29 . A product comprising the purified steviol glycoside mixture of  claim 29 , wherein the product is selected from the group consisting of a food, a beverage, a pharmaceutical composition, a tobacco product, a nutraceutical composition, an oral hygiene composition, and a cosmetic composition. 
     
     
         30 . A purified steviol glycoside mixture made by a method comprising the steps of:
 a. providing a biomass of a  Stevia rebaudiana  Bertoni plant;   b. producing a crude extract by contacting the biomass with water;   c. separating insoluble material from the crude extract to obtain a filtrate containing steviol glycosides;   d. treating the filtrate to remove high molecular weight compounds and insoluble particles to obtain the solution of steviol glycosides;   e. providing a plurality of consecutively connected columns packed with an adsorbent resin capable of adsorbing steviol glycosides to create a multi-column system;   c. passing the solution of steviol glycosides through the multi-column system to obtain at least two columns, each column having a different ratio of adsorbed steviol glycosides; and   d. eluting the adsorbed steviol glycosides from at least one column in the multi-column system, to obtain an eluted solution comprising the purified steviol glycoside mixture.   
     
     
         31 . A purified steviol glycoside mixture with at least about 95% by weight total steviol glycosides made by a method comprising the steps of:
 a. providing a biomass of a  Stevia rebaudiana  Bertoni plant;   b. producing a crude extract by contacting the biomass with water;   c. separating insoluble material from the crude extract to obtain a filtrate containing steviol glycosides;   d. treating the filtrate to remove high molecular weight compounds and insoluble particles to obtain the solution of steviol glycosides;   e. providing a plurality of consecutively connected columns packed with an adsorbent resin capable of adsorbing steviol glycosides to create a multi-column system;   f. passing the solution of steviol glycosides through the multi-column system to obtain at least two columns, each column having a different ratio of adsorbed steviol glycosides;   g. eluting the adsorbed steviol glycosides from at least one column in the multi-column system, to obtain an eluted solution comprising purified steviol glycosides;   h. decolorizing and deionizing the eluted solution comprising steviol glycosides to obtain a decolorized, deionized steviol glycoside solution; and   i. drying the decolorized, deionized steviol glycoside solution to obtain the purified steviol glycoside mixture with at least about 95% by weight total steviol glycosides.   
     
     
         32 . A product comprising the purified steviol glycoside mixture of  claim 30 , wherein the product is selected from the group consisting of a food, a beverage, a pharmaceutical composition, a tobacco product, a nutraceutical composition, an oral hygiene composition, and a cosmetic composition. 
     
     
         33 . A product comprising the purified steviol glycoside mixture of  claim 31 , wherein the product is selected from the group consisting of a food, a beverage, a pharmaceutical composition, a tobacco product, a nutraceutical composition, an oral hygiene composition, and a cosmetic composition.