A kind of preparation method of high-purity EGCG

Abstract

The invention discloses a method for preparing high-purity EGCG. The method comprises the following steps: dissolving tea polyphenol raw materials by using ethanol so as to obtain a tea polyphenol solution; passing through a chromatographic column filled with a non-polar macroporous resin, performing eluting pretreatment with purified water, eluting with ethanol, collecting the eluent, and concentrating so as to obtain the concentrated eluent; finally, separating and purifying through a three-component simulated moving bed, and crystallizing the separated and purified EGCG through a low-temperature vacuum decompression concentration manner, so as to obtain the high-purity EGCG product. The method disclosed by the invention is based on the three-component simulated moving bed separation technology, the non-polar macroporous resin with low price serves as a separation carrier, and continuous and high-efficiency separation of the EGCG and other compounds can be realized; the purity of the separated EGCG is 95% or higher, the yield is 80% or higher, the purity of the crystallized product is 99% or higher, and the recovery rate is 95% or higher.

Description

technical field [0001] The invention belongs to the technical field of natural product purification, in particular to a preparation method of high-purity EGCG. Background technique [0002] Tea polyphenols are mainly composed of catechins, flavonoids, phenolic acids, and anthocyanins. Catechins account for 60% to 80% of the total tea polyphenols. Modern research shows that catechin is not only an ideal natural antioxidant, but also a class of extremely valuable natural pharmaceutical raw materials. effect. The catechin monomer compounds in tea polyphenols mainly include epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), gallocatechin gallate (GCG) ) and epigallocatechin gallate (EGCG), among which the most biologically active is EGCG. In recent years, developed countries in the world have actively promoted the development and application of catechin products. As natural antioxidants and free radical scavengers, they have been widely used in food process...

AI Technical Summary

Problems solved by technology

However, due to the low solubility of tea polyphenols in supercritical CO2, the yield of separation is very low

[0004] Chinese patents 201410562697.1 and 200910273058.2 disclose the use of single-column chromatography to separate and purify EGCG. Although the single-column processing capacity is large, it cannot achieve the purpose of continuous separation and the operation is cumbersome.

And the separation resin used is all reversed-phase silica gel C18, which is expensive, eluted with ethanol, has a large dead adsorption, and has a high scrap rate of the resin, so it is not suitable for industrial production

In addition, the patent 201410766716.2 uses a hydrogen-bonding macroporous adsorption resin as the separation resin. The resin selected has the characteristics of high adsorption rate and low desorption rate or low adsorption rate and high desorption rate. It is easy to be poisoned when used to prepare EGCG resin. low rate

Patent 201110171485.7 uses a two-component simulated moving bed to separate and purify EGCG. Since EGCG is an intermediate eluting component, there is interference from other components before and after. Using a two-component simulated moving bed must be separated in two steps. The patent used The simulated moving bed is of small scale and the separation resin used is reversed-phase silica gel C18, which has high cost and high resin scrap rate, and the concentration method adopted is rotary evaporation, which has poor concentration efficiency, is not easy to concentrate at low temperature, and is easy to concentrate for a long time Oxidation of EGCG; high temperature concentration time is short, but EGCG is more likely to be oxidized

Therefore, the process is not suitable for industrial production

In addition, there are different degrees of dead adsorption in the adsorption resins, and the desorption rate cannot reach 100%, and some EGCG will be taken out of the components before and after two separations, so the recovery rate of EGCG is low.

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