Method for the enrichment of rebaudioside b and/or rebaudioside d in stevia-derived glycoside compositions using adsorb-desorb chromatography with a macroporous neutral adsorbent resin

Abstract

The invention relates to the use of adsorb/desorb chromatography to prepare enriched compositions comprising rebaudioside B and/or rebaudioside D. Compositions with enriched rebaudioside-B and/or rebaudioside-D components may be prepared from Stevia-derived glycoside compositions using an adsorb-desorb chromatography process where the stationary phase of the chromatography bed comprises a macroporous neutral adsorbent resin.

1 . A method of preparing an enriched composition comprising rebaudioside B and rebaudioside D, the method comprising the steps of:
 (A) contacting a macroporous neutral adsorbent resin with a glycoside solution, which solution has a pH from about 8 to about 11 and comprises rebaudioside B, rebaudioside D, and at least one other steviol glycoside, so that at least a portion of glycosides in the glycoside solution are adsorbed onto the macroporous neutral adsorbent resin; and   (B)   contacting that macroporous neutral adsorbent resin with at least one elution solvent formulated to selectively elute rebaudioside B and rebaudioside D from the adsorbent and comprising about 10-50% w/w ethanol and about 50-90% w/w water, thereby eluting a composition enriched, relative to the glycoside solution, with rebaudioside B and rebaudioside D.   
     
     
         2 . The method according to  claim 1 , wherein the pH of the glycoside solution ranges from a pH of about 8 to a pH of about 10. 
     
     
         3 . (canceled) 
     
     
         4 . The method according to  claim 2 , wherein the at least one elution solvent comprises about 20-35% w/w ethanol and about 65-80% w/w water. 
     
     
         5 . (canceled) 
     
     
         6 . The method according to  claim 1  wherein the method further comprises, after step (B), eluting at least a portion of remaining adsorbed glycosides from the macroporous neutral adsorbent resin. 
     
     
         7 . The method according to  claim 1 , wherein the method further comprises, after step (B), eluting at least a portion of remaining adsorbed glycosides from the macroporous neutral adsorbent resin with a subsequent elution solvent that comprises about 36-100% w/w ethanol and about 0-64% w/w water, and the composition eluted with the subsequent elution solvent is enriched, relative to the steviol glycoside solution, with rebaudioside A. 
     
     
         8 . (canceled) 
     
     
         9 . The method according to  claim 25 , wherein the at least one elution solvent comprises about 20-35% w/w ethanol and about 65-80% w/w water. 
     
     
         10 . The method according to  claim 25 , wherein the at least one elution solvent comprises about 25-33% w/w ethanol and about 67-75% w/w water. 
     
     
         11 . (canceled) 
     
     
         12 . The method according to  claim 25 , wherein the pH of the Stevia-derived glycoside solution ranges from a pH of about 5 to a pH of about 6. 
     
     
         13 . (canceled) 
     
     
         14 . The method according to  claim 27 , wherein the pH of the glycoside solution ranges from a pH of about 1 to a pH of about 3. 
     
     
         15 . The method according to  claim 27 , wherein the at least one first elution solvent comprises about 40-60% w/w ethanol and about 40-60% w/w water. 
     
     
         16 . (canceled) 
     
     
         17 . The method according to  claim 15 , wherein the first eluted composition is enriched with rebaudioside D. 
     
     
         18 - 20 . (canceled) 
     
     
         21 . The method according to  claim 15 , wherein the first eluted composition is enriched with rebaudioside A. 
     
     
         22 . The method according to  claim 21 , wherein the second elution solvent comprises from about 70-100% w/w ethanol and about 0-39% w/w water. 
     
     
         23 . The method according to  claim 1 , wherein the macroporous neutral adsorbent resin comprises a macroporous resin of divinyl benzene. 
     
     
         24 . An enriched composition prepared according to the method of  claim 1 . 
     
     
         25 . A method of preparing an enriched composition comprising rebaudioside D, the method comprising the steps of:
 (A) contacting a macroporous neutral adsorbent resin with a glycoside solution, which solution has a pH from about 4 to about 6 and comprises rebaudioside D and at least one other steviol glycoside, so that at least a portion of glycosides in the glycoside solution are adsorbed onto the macroporous neutral adsorbent resin; and   (B) contacting that macroporous neutral adsorbent resin with at least one elution solvent formulated to selectively elute rebaudioside D from the adsorbent and comprising about 10-40% w/w ethanol and about 60-90% w/w water, thereby eluting a composition enriched with rebaudioside D.   
     
     
         26 . The method according to  claim 25 , wherein the method further comprises, after step (B), eluting at least a portion of remaining adsorbed glycosides from the macroporous neutral adsorbent resin. 
     
     
         27 . A method of preparing an enriched composition comprising rebaudioside B, the method comprising the steps of:
 (A) contacting a macroporous neutral adsorbent resin with a glycoside solution, which solution has a pH from about 1 to about 4 and comprises rebaudioside B and at least one of rebaudioside A and rebaudioside D, so that at least a portion of glycosides in the glycoside solution are adsorbed onto the macroporous neutral adsorbent resin;   (B) contacting that macroporous neutral adsorbent resin with at least one first elution solvent formulated to selectively elute rebaudioside A, rebaudioside D, or a mixture thereof from the adsorbent and comprising about 10-60% w/w ethanol and from about 40-80% w/w water, thereby eluting a first eluted composition with rebaudioside A, rebaudioside D, or a mixture thereof; and, subsequently,   (C) contacting the macroporous neutral adsorbent resin with at least one second elution solvent comprising about 60-100% w/w ethanol and about 0-40% w/w water, thereby eluting a second eluted composition enriched, relative to the glycoside solution, with rebaudioside B.   
     
     
         28 . An enriched composition prepared according to the method of  claim 25 . 
     
     
         29 . An enriched composition prepared according to the method of  claim 27 .