Method to elevate the amount of steviol glycosides remained in the recrystallization mother liquor of Stevia extract

Patent metadata

Field	Value
Publication number	US-12012628-B2
Application number	US-202017105781-A
Country	US
Kind code	B2
Filing date	Nov 27, 2020
Priority date	Dec 4, 2018
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

The disclosure discloses a method to elevate the amount of steviol glycosides remained in the recrystallization mother liquor of Stevia extract, and belongs to the field of modification and extraction of natural compounds. The disclosure adopts lactase for highly specific catalytic hydrolysis of stevioside to convert stevioside into rubusoside which usually can only be obtained from leaves of Rubus suavissimus S. Lee; and meanwhile, after stevioside in the mother liquor glycosides is converted, since the polarity difference between rubusoside and rebaudioside A is far larger than the polarity difference between stevioside and rebaudioside A, rebaudioside A is more easily separated out of the mother liquor glycosides. A technology provided by the disclosure is also applicable to value increment of mixed steviol glycosides containing stevioside and is beneficial for separating out rebaudioside A from the mixed steviol glycosides.

First claim

What is claimed is:

1. A method of preparing rubusoside from Stevia mother liquor glycosides, comprising:
adding lactase from Kluyveromyces fragilis to the Stevia mother liquor glycosides and incubating for 1 to 3 hours at a temperature of 25° C. to 45° C. for specific catalytic hydrolysis of stevioside in the Stevia mother liquor glycosides, so that stevioside is hydrolyzed into rubusoside, wherein rebaudioside A remains in the Stevia mother liquor glycosides and is not acted upon by the lactase; and
separating rubusoside and rebaudioside A, wherein other steviol glycosides including rebaudioside A are separated excluding rubusoside through exclusion chromatography or recrystallization;
wherein an enzyme concentration of the lactase is 10 U/g to 100 U/g stevioside, and mass of the added lactase does not exceed 1% of mass of the Stevia mother liquor glycosides-used.

2. The method according to claim 1 , wherein the Stevia mother liquor glycosides are mother liquor or a dry product of the mother liquor generated after the steviol glycosides are extracted or purified in a process of extracting the steviol glycosides from Stevia rebaudiana leaves.

3. The method according to claim 2 , wherein the enzyme concentration of the lactase is 10U/g to 60 U/g stevioside.

4. The method according to claim 3 , wherein pH of the substrate is 4 to 6 during the catalytic reaction with the lactase.

5. The method according to claim 1 , wherein the Stevia mother liquor glycosides is replaced with mixed steviol glycosides containing stevioside.

6. The method according to claim 1 , wherein a solution with a predetermined concentration is prepared first by adding water to the Stevia mother liquor glycosides, and then the lactase is added to catalyze stevioside to produce rubusoside; and a mass concentration of steviol glycosides in an aqueous solution of the Stevia mother liquor glycosides is 100 g/L to 500 g/L.

7. The method of claim 1 , further comprising: separating rubusoside and rebaudioside A by spray-drying and then recrystallizing in 95% ethanol to separate out rubusoside.

8. A method of converting stevioside to rubusoside, comprising:
incubating lactase from Kluyveromyces fragilis with stevioside to hydrolyze stevioside into rubusoside.

9. The method according to claim 8 , wherein the lactase comes from Kluyveromyces fragilis , the lactase exists in a form of a concentrated solution, freeze-dried powder or an immobilized enzyme, and an enzyme concentration does not exceed 1% of mass of Stevia mother liquor glycosides used.

10. The method according to claim 8 , wherein the reaction is performed for 1 to 3 hours at a temperature of 25° C. to 45° C.

11. The method according to claim 9 , wherein the reaction is performed for 1to 3 hours at a temperature of 25° C. to 45° C.

12. The method according to claim 10 , wherein the reaction is performed for 2to 3 hours at a temperature of 30° C.

Assignees

• Univ Jiangnan

Inventors

• Xia Yongmei
• Zhou Zhuoyu
• Fan Ye
• Hu Xueyi
• Fang Yun
• Liu Xiang
• Wang Haijun
• Wu Jing
• Xu Fei

Classifications

• C12P19/14

  produced by the action of a carbohydrase {(EC 3.2.x)}, e.g. by alpha-amylase {, e.g. by cellulase, hemicellulase} · CPC title

• A23V2002/00

  Food compositions, function of food ingredients or processes for food or foodstuffs · CPC title

• A23L27/36

  Terpene glycosides · CPC title

• C07H15/256

  Polyterpene radicals · CPC title

• C12P19/56 Primary

  having an oxygen atom of the saccharide radical directly bound to a condensed ring system having three or more carbocyclic rings, e.g. daunomycin, adriamycin · CPC title