阅读说明：本技术 一种甜菊苷的纯化方法 (Method for purifying stevioside ) 是由 张�杰 李宇琪 冯锋 柳文媛 白一丹 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种甜菊苷的纯化工艺,包括：将甜菊苷粗品超声溶解于甲醇水混合溶剂中,0～4℃重结晶,过滤、干燥得到甜菊苷纯品；其中,所述的甲醇水混合溶剂的含水量为2～10％,甜菊苷粗品和甲醇水混合溶剂的用量比为1:3～1:5g/mL,重结晶时间为9～15h。本发明采用重结晶法纯化甜菊苷,只需一次结晶就可以将纯度从50～60％提高到90％以上,纯化甜菊苷的效果显著,甜菊苷回收率在55％左右,且无有害溶剂,适合工业生产。(The invention discloses a stevioside purification process, which comprises the following steps: ultrasonically dissolving the stevioside crude product in a methanol-water mixed solvent, recrystallizing at 0-4 ℃, filtering, and drying to obtain a stevioside pure product; the water content of the methanol-water mixed solvent is 2-10%, the using amount ratio of the stevioside crude product to the methanol-water mixed solvent is 1: 3-1: 5g/mL, and the recrystallization time is 9-15 h. The stevioside is purified by a recrystallization method, the purity can be improved from 50-60% to more than 90% by one-time crystallization, the stevioside purification effect is obvious, the stevioside recovery rate is about 55%, no harmful solvent is generated, and the stevioside purification method is suitable for industrial production.)

1. A method for purifying stevioside, which is characterized by comprising the following steps: ultrasonically dissolving the stevioside crude product in a methanol-water mixed solvent, recrystallizing at 0-4 ℃, filtering, and drying to obtain a stevioside pure product; wherein, the water content of the methanol-water mixed solvent is 2-10%.

2. The method for purifying stevioside according to claim 1, wherein the using amount ratio of the crude stevioside product to the methanol-water mixed solvent is 1: 3-1: 5 g/mL.

3. The method for purifying stevioside according to claim 2, wherein the ratio of the crude stevioside product to the methanol-water mixed solvent is 1:5 g/mL.

4. A purification method of stevioside according to claim 1 characterized in that the recrystallization time is 9-15 h.

5. A purification process of stevioside according to claim 4 characterized by recrystallization time of 12 h.

6. A purification process of stevioside according to claim 1 characterized in that the water content of the methanol-water mixed solvent is 5%.

7. The method for purifying stevioside according to claim 1, wherein the purity of the crude stevioside product is 50-60%.

Technical Field

The invention relates to a method for purifying stevioside.

Background

Stevioside is a natural sweetening agent, has the characteristics of high sweetness, low calorie, no toxicity and the like, and is known as the third sugar source in the world. The food additive has good stability, good salt resistance, no Maillard browning phenomenon, is not easy to assimilate and ferment by microorganisms, can be used as a food additive to prolong the shelf life of food, has great edible value and also has various pharmacological activities, such as: reducing blood sugar and blood pressure has health-assisting effect on human body, so that high-purity stevioside is indispensable in deep research and development.

The method for separating and purifying stevioside mainly comprises recrystallization, macroporous resin adsorption separation, high performance liquid chromatography, high speed counter current chromatography, capillary electrophoresis, supercritical extraction, etc. The recrystallization method is simple and convenient to operate, is common in a production process of stevioside (a mixture of total stevioside), is used for purifying stevioside, and has relatively few reports on industrial recrystallization purification of stevioside monomer compounds. Hades and the like adopt methanol water to purify 90% stevioside, the requirement on the purity of a sample is high, the consumption of industrial production raw materials is large, the production cost is increased, and repeated crystallization is needed for multiple times to achieve the target yield. In addition, isopropanol, methanol, and ethanol have been reported as solvents for recrystallization. But the use of isopropanol as a crystallization solvent increases the production cost, and the high-concentration volatile isopropanol has stimulation effect on the eye and respiratory tract mucous membranes, thereby having potential safety hazard. The large-scale use of the remaining pure organic solvents likewise poses safety problems and increases the consumption of pure solvents. The method has the advantages that the method is extremely low in treatment amount, and is not suitable for industrial mass production of high-purity stevioside at present, Yuanyangping and the like adopt a three-zone simulated moving bed chromatographic separation system to separate and obtain high-purity stevioside and rebaudioside A from the stevioside, the process is simple, chromatographic fillers are consumed, and the production cost is increased.

Disclosure of Invention

The invention aims to provide a stevioside purification method aiming at the defects of high purity requirement of stevioside recrystallization raw materials, large using amount of recrystallization solvent, long recrystallization time, safety and the like.

The purpose of the invention is realized by the following technical scheme:

a method for purifying stevioside, comprising: ultrasonically dissolving the stevioside crude product in a methanol-water mixed solvent, recrystallizing at 0-4 ℃, filtering, and drying to obtain a stevioside pure product; wherein the water content (volume percentage concentration) of the methanol-water mixed solvent is 2-10%; the using amount ratio of the stevioside crude product to the methanol-water mixed solvent is 1: 3-1: 5 g/mL; the recrystallization time is 9-15 h.

The stevioside crude product contains 50-60% of stevioside, 10-15% of rebaudioside A and 5-10% of rebaudioside C. The less polar (relative to the stevioside polarity) glycosides (e.g., rebaudioside C) and phenolics in the crude stevioside product are the major removed impurities, followed by the more polar glycosides (e.g., rebaudioside A). And compared with stevioside, the large polar glycoside is more easily separated out in pure methanol, so the addition of a small amount of water can slow down the crystallization of the large polar glycoside.

Preferably, the water content of the methanol-water mixed solvent is 5%.

Preferably, the dosage ratio of the crude stevioside product to the methanol-water mixed solvent is 1:5 g/mL.

Preferably, the recrystallization time is 12 hours.

The invention has the following beneficial effects:

the stevioside is purified by a recrystallization method, the purity can be improved from 50-60% to more than 90% by one-time crystallization, the stevioside purification effect is obvious, the single recovery rate of the stevioside is about 55%, no harmful solvent is contained, and the stevioside purification method is suitable for industrial production. In addition, the recrystallization mother liquor can be subjected to secondary recrystallization after the solvent is recovered, the total recovery rate of stevioside can be improved, the recycling of the organic solvent is increased, and the emission of the organic solvent is reduced.

Drawings

FIG. 1 shows the effect of solvent water content on stevioside purity in single factor experiment results.

FIG. 2 is a graph showing the effect of solvent water content on crystallization rate in a single factor experiment;

FIG. 3 is a graph showing the effect of feed-to-liquid ratio on stevioside purity in a single factor experiment;

FIG. 4 is a graph showing the effect of feed liquid ratio on crystallization rate in a single factor experiment result;

FIG. 5 is a graph showing the effect of crystallization time on stevioside purity in a single factor experiment;

FIG. 6 is a graph showing the effect of crystallization time on the crystallization rate in the results of a single factor experiment.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The technical solutions of the present invention can be better understood by those skilled in the art based on the examples of the present invention, but the present invention is not limited in any way.