Methods to treat mixtures of glycosides to obtain one or more of these glycosides in more pure form

Abstract

The present invention provides methods to treat mixtures containing natural rebaudioside A (Reb A), rebaudioside B (Reb B), and rebaudioside D (Reb D), synthetic counterparts of these, and/or derivatives of the natural or synthetic embodiments obtain one or more of these glycosides in more pure form. In many embodiments, the invention can be used to process glycoside mixtures obtained at least in part from natural sources such as the Stevia plant. This allows, for instance, the recovery of a product including Reb A material in more pure form relative to Reb B material or Reb D material. As an alternative or in addition to recovery of the purified Reb A material, a product including Reb B material and/or Reb D material in more pure form relative to Reb A material can be obtained.

1 - 62 . (canceled) 
     
     
         63 . A method of treating a glycoside mixture comprising rebaudioside A material and at least one of rebaudioside B material or rebaudioside D material to help recover at least one of rebaudioside A material, rebaudioside B material or rebaudioside D material in more pure form, comprising the steps of:
 a) providing a slurry comprising glycosides including at least rebaudioside A material and at least one of rebaudioside B material and rebaudioside D material, wherein the slurry includes a solid phase and a liquid phase;   b) aging the slurry at one or more elevated temperatures independently greater than about 40° C., said aging occulting for a time period sufficient for the solid phase to become more pure with respect to at least one of the rebaudioside A material, rebaudioside B material and rebaudioside D material;   c) filtering the heated mixture to separate the solid and liquid phases, wherein the mixture is at a temperature of at least 40° C. during at least a portion of the filtering; and   d) recovering at least one glycoside in at least one of the solid and liquid phases.   
     
     
         64 . The method of  claim 63 , wherein step (d) comprises recovering a solid phase comprising rebaudioside A material. 
     
     
         65 . The method of  claim 63 , wherein step (d) comprises recovering a liquid phase comprising at least one of rebaudioside B material and rebaudioside D material. 
     
     
         66 . The method of  claim 65 , further comprising the step of processing the liquid phase to recover a solid phase containing at least one of rebaudioside B material and rebaudioside D material. 
     
     
         67 . The method of  claim 63 , wherein the slurry provided in step (a) includes from about 20 weight percent to about 96 weight percent of rebaudioside A material. 
     
     
         68 . The method of  claim 63 , wherein the slurry provided in step (a) includes at least about 3 weight percent total of rebaudioside B material and rebaudioside D material. 
     
     
         69 . The method of  claim 63 , wherein the slurry provided in step (a) includes at least about 6 weight percent total of rebaudioside B material and rebaudioside D material. 
     
     
         70 . The method of  claim 63 , wherein the slurry is treated in step (b) under conditions such that the solid phase resulting from step (c) includes at least 80 weight percent rebaudioside A material. 
     
     
         71 . The method of  claim 63 , wherein the slurry is treated in step (b) under conditions such that the solid phase resulting from step (c) includes at least 90 weight percent rebaudioside A material. 
     
     
         72 . The method of  claim 63 , wherein the slurry is treated in step (b) under conditions such that the solid phase resulting from step (c) includes at least 96 weight percent rebaudioside A material. 
     
     
         73 . The method of  claim 63 , wherein the slurry is treated in step (b) under conditions such that the solid phase resulting from step (c) comprises a crystalline phase that includes up to about 3 weight percent total rebaudioside B material and rebaudioside D material. 
     
     
         74 . The method of  claim 63 , wherein the liquid phase in at least one of steps (a) through (d) comprises at least one alcohol. 
     
     
         75 . The method of  claim 74 , wherein the alcohol is an aqueous alcohol. 
     
     
         76 . The method of  claim 63 , wherein the liquid phase in at least one of steps (a) through (d) comprises an alcohol selected from ethanol, isopropanol, methanol, n-butanol, and combinations thereof. 
     
     
         77 . The method of  claim 76 , wherein the alcohol is an aqueous alcohol. 
     
     
         78 . The method of  claim 63 , wherein the liquid phase in at least one of steps (a) through (d) comprises water. 
     
     
         79 . The method of  claim 63 , wherein the slurry provided in step (a) comprises an alcohol crystalline form of at least one of rebaudioside A material, rebaudioside B material, and rebaudioside D material. 
     
     
         80 . The method of  claim 63 , wherein aging occurs at a temperature of at least about 50° C. 
     
     
         81 . The method of  claim 63 , wherein aging occurs at a temperature of at least about 70° C. 
     
     
         82 . The method of  claim 63 , wherein aging occurs at a temperature of at least about 70° C. and a pressure greater than ambient pressure. 
     
     
         83 . The method of  claim 63 , wherein aging occurs at an absolute pressure in the range from about 1.1 atm to about 30 atm. 
     
     
         84 . The method of  claim 63 , wherein aging occurs at an absolute pressure in the range from about 1.1 atm to about 10 atm. 
     
     
         85 . The method of  claim 63 , wherein aging occurs at an absolute pressure in the range from about 1.1 atm to about 5 atm. 
     
     
         86 . The method of  claim 63 , wherein aging occurs with mixing in the presence of a cooling surface that is at a temperature less than the bulk temperature of the mixture. 
     
     
         87 . The method of  claim 86 , wherein at least a portion of the cooling surface is at a temperature of under about 40° C.