Separation of rebaudioside A from stevia glycosides using chromatography
Disclosed are methods for the chromatographic separation of rebaudioside A from stevioside in glycoside solutions that are derived from stevia. The chromatographic separation may be an adsorb/desorb type of chromatographic separation or a fractionation type of chromatographic separation.
1. A method of separating rebaudioside A from stevioside using chromatography, the method comprising the steps of:
(a) providing a glycoside solution comprising rebaudioside A; stevioside; and a solvent;
(b) providing an adsorbent comprising a polystyrene divinylbenzene support functionalized with tertiary amines, quaternary amines, or both tertiary and quaternary amines; and
(c) contacting the adsorbent with the glycoside solution in order to separate at least a portion of the rebaudioside A from the stevioside thereby resulting in the formation of a purified rebaudioside A solution.
2. The method of claim 1 , wherein the method of separating comprises adsorb/desorb chromatography.
3. The method of claim 2 , wherein the adsorb/desorb chromatography comprises the steps of
(a) providing a glycoside solution comprising rebaudioside A; stevioside; and a solvent;
(b) providing an adsorbent comprising a polystyrene divinylbenzene support functionalized with tertiary amines, quaternary mines, or both tertiary and quaternary amines;
(c) providing an elution solvent;
(d) contacting the adsorbent with the glycoside solution and elution solvent so that at least a portion of the stevioside adsorbs onto the adsorbent enriching the glycoside solution in rebaudioside A and resulting in the formation of a purified rebaudioside A composition that is eluted from the adsorbent along with the elution solvent; and
(e) optionally, desorbing the stevioside from the adsorbent.
4. The method of claim 3 , wherein the elution solvent comprises about 20% weight or less ethanol; and about 80% weight or greater water.
5. The method of claim 3 , wherein the elution solvent comprises about 50% weight or less ethanol; and about 50% weight or greater water.
6. The method of claim 1 , wherein the method of separating comprises fractionation chromatography.
7. The method of claim 6 , wherein the fractionation chromatography comprises the steps of:
(a) providing a glycoside solution comprising rebaudioside A; stevioside; and a solvent;
(b) providing an adsorbent comprising a polystyrene divinylbenzene support functionalized with tertiary amines, quaternary mines, or both tertiary and quaternary amines; and
(c) contacting the adsorbent with the glycoside solution so that at least a portion of the stevioside adsorbs onto the adsorbent and so that at least a portion of the rebaudioside A adsorbs onto the adsorbent; wherein the rebaudioside A propagates through the adsorbent at a faster rate than the stevioside; and
(d) collecting a purified rebaudioside A solution from the adsorbent.
8. The method of claim 7 , wherein the solvent comprises about 20% weight or greater ethanol and about 80% weight or less water.
9. The method of claim 7 , wherein the solvent comprises about 25% to about 35% weight ethanol and about 65% to about 75% water.
10. The method of claim 7 , wherein the solvent comprises water and wherein the adsorbent is a strongly acidic cationic exchange resin.
11. The method of claim 7 , wherein the glycoside solution further comprises one or more glycoside selected from rebaudioside B and rebaudioside D; and wherein the method provides a separation between stevioside, rebaudioside A, rebaudioside B, and rebaudioside D.
12. The method of claim 11 , wherein the method provides a separation between stevioside, rebaudioside A, rebaudioside B, and rebaudioside D.
13. The method of claim 6 , wherein the fractionation chromatography is performed using a simulated moving bed.
14. The method of claim 1 , wherein the adsorbent has a surface area of about 900 m2/gram or greater.
15. The method of claim 1 , wherein the adsorbent is functionalized with tertiary amines.
16. The method of claim 1 , wherein the adsorbent is functionalized with quaternary amines.
17. The method of claim 1 , wherein the glycoside solution is a mother liquor from a rebaudioside A crystallization process.
18. The method of claim 1 , wherein the purified rebaudioside A solution has a purity that is about 10% or greater as compared to a purity of the glycoside solution.
19. The method of claim 1 , wherein the purified rebaudioside A solution comprises, on a dry solids basis, about 60% weight to about 80% weight rebaudioside A.
20. The method of claim 1 , wherein the glycoside solution further comprises one or more glycosides selected from rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside E, rebaudioside F, and dulcoside.
21. The method of claim 20 , wherein the glycoside solution comprises one or more glycosides selected from rebaudioside B and rebaudioside D.