JPH1067771A - Production of catechins having low catechin content - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing high-purity catechin by efficiently removing caffeine contained in tea leaf. SOLUTION: This method comprises an absorption step for absorbing catechins by passing an extract containing catechins obtained by extracting tea leaf with hot water through a chromatographic column in which an absorbent is packed, a washing step for washing a part of caffeine which is methylxanthine away by washing the chromatographic column with water and an elution step for eluting catechines absorbed in the chromatographic column from the chromatographic column by using one kind of methanol, ethanol and acetone solvents or aqueous solution thereof as an eluent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing high-purity catechins which can remove a part or most of caffeine which is a methylxanthine.

[0002]

2. Description of the Related Art It is a known fact that catechins are extracted from tea leaves with hot water, and a method of extracting catechins with an organic solvent is also generally known. In both extraction methods, methylxanthine contained in tea leaves is extracted simultaneously with catechins. Therefore, caffeine as a typical methylxanthine is generally contained in catechins and extracted. Therefore, as a method for removing caffeine from the extract, a method of removing by adsorption with an adsorption resin (Diaion HP-2MG, HP-1MG Mitsubishi Kasei), activated carbon, or the like is used.

[0003]

However, in these conventional adsorption and removal methods, caffeine to be removed is also adsorbed together with catechins. In order to remove the caffeine, the adsorption resin or the like is washed with water or a low-concentration alcohol aqueous solution. In this case, a very large amount of water is required. In this method, caffeine still remains at 14 to 15% or more, so that caffeine cannot be significantly reduced. In addition, even when a low-concentration aqueous alcohol solution is used, there is a possibility that adsorbed catechins may be eluted at the same time, leading to loss of catechins.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In the production of catechins, caffeine is efficiently removed and the physiological activity of catechins is reduced. An object of the present invention is to provide a method for producing catechins in which caffeine is significantly reduced for effective use.

[0005] Therefore, the present invention provides a method for removing caffeine, which is a methylxanthine, from an extract extracted from tea leaves with hot water by using a chromatocolumn filled with a cyclodextrin polymer to remove caffeine only. The production of catechins with reduced amount of caffeine is said to be able to remove a part or most of caffeine with a small amount of 50-100 times smaller than conventional water without using an alcohol aqueous solution. Find out how.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention uses a cyclodextrin polymer as an adsorbent to be packed in a chromatographic column, passes an extract through the adsorbent to adsorb catechins, and then prepares a methylxanthine Washing the chromatographic column with only a small amount of water without using a low-concentration alcohol aqueous solution of caffeine, and a washing step to remove a part or most of the caffeine, An elution step of eluting with one of acetone or an aqueous solution having a low concentration of acetone.

The adsorbent may be a cyclodextrin polymer in which cyclodextrin is bonded to a carrier made of an acrylic three-dimensional crosslinked polymer having a hydrophilic macroporous structure. For example, α-C
D polymer (manufactured by Saltwater Port Refining) and β-CD polymer (manufactured by Saltwater Port Refining).

[0008] The amount of water in the washing step can be a volume ratio of 2 to 10 with respect to the adsorbent.

The adsorbent used in the present invention allows most of the weakly polar caffeine to pass through without being adsorbed, and adsorbs strongly polar catechins. Therefore, even in the washing step with water, some caffeine remaining in the adsorbent is flushed away, so that the amount of water can be removed in a small amount of about twice the adsorbent volume.

The eluent in the elution step is 80% to 30%.
% Aqueous solutions can be used.

The volume of the eluent in the elution step may be a volume ratio of 1 to 2 with respect to the adsorbent.

The present invention will be specifically described based on the following examples.

[0013]

Example 1 100 ml of hot water was added to 5 g of tea leaves,
Extraction was performed while stirring for minutes. The tea leaves were removed by filtration to obtain a filtrate of about 100 mL. This filtrate is loaded on a chromatographic column having an inner diameter of 2.1 cm and a height of 25 cm filled with 35 mL of cyclodextrin polymer as an adsorbent, and the adsorption speed is set to SV3 to start adsorption under natural flow. After the completion of the adsorption step, in the washing step, washing was performed using 70 mL of water twice the volume ratio of the adsorbent. Next, 50 mL of a 60% aqueous ethanol solution was passed through the chromatographic column as an eluent to elute catechins, and the catechin solution 5 was eluted.
0 mL was obtained.

The extract obtained by hot water extraction from tea leaves, the liquid passed through the chromatographic column in the adsorption step, the washing water from the chromatographic column solution outlet in the washing step, and the catechins solution from the eluent in the elution step are each separated by a high-speed liquid. When the components were analyzed by chromatography (HPLC), the height of each peak with caffeine in the extract of FIG. 1 and epigallocatechin gallate (EGCg) as the main component in the catechins in the catechin solution in FIG. It was confirmed from the ratio of that caffeine was reduced. This numerical value is as shown in Table 1.

[0015]

[Table 1] In addition, each code | symbol of the component analysis of HPLC shown in FIGS. 1-4 shows each substance as follows, respectively.

-Epigallocatechin-catechin
-Caffeine-epigallocatechin gallate-epicatechin-epicatechin gallate-catechin gallate

[0017]

EXAMPLE 2 1.8 L of hot water was added to 90 g of tea leaves, and the same operation as in Example 1 was performed. This solution was filled with an adsorbent cyclodextrin polymer (400 mL) and had an inner diameter of 4 c.
The chromatography column having a height of 55 cm and a height of 55 cm is loaded, the adsorption speed is set to SV3, and the adsorption is started under natural flow. After completion of the adsorption step, 800 mL (2% by volume of the adsorbent)
The mixture was washed with water, and a 40% aqueous solution of ethanol (500 mL) was passed through a chromatography column as an eluent to elute catechins to obtain a catechin solution (500 mL). This solution was concentrated under reduced pressure to obtain 20.2 g of a concentrated solution.

As a result of component analysis of this concentrate by HPLC, caffeine and epigallocatechin gallate (EG
The ratio of the height of each peak to Cg) was as shown in Table 2, and it was confirmed that a catechin solution containing low caffeine was obtained.

[0019]

[Table 2] Table 3 shows the content of each catechin.

[0020]

[Table 3]

[0021]

According to the present invention, caffeine adsorbed on an adsorbent can be washed into water without using a low-concentration aqueous alcohol solution as in the prior art, and the amount thereof is about twice that of the adsorbent. It is a small amount or 50 to 100 times smaller than the conventional water usage. Further, since the eluent for eluting catechin can be used even at a low concentration of 30%, the above-mentioned low-concentration aqueous alcohol solution is not required, the amount of water used for washing is reduced, and the eluent can be used at a low concentration, thereby reducing the cost. Can be very low. In addition, the fact that the water usage is small means that the cleaning time is also shortened.

[Brief description of the drawings]

FIG. 1 shows a component analysis of a tea leaf extract by HPLC.

FIG. 2 shows a component analysis by HPLC of a flow-through liquid in an adsorption step.

FIG. 3 shows a component analysis by HPLC of washing water in a washing step.

FIG. 4 shows component analysis of a catechin solution by HPLC.

[Description of Signs]-Epigallocatechin-Catechin-Caffeine-Epigallocatechin gallate-Epicatechin-Epicatechin gallate-Catechin gallate

Claims (5)

[Claims] 1. An adsorption step in which an extract extracted from tea leaves is passed through a chromatographic column filled with an adsorbent to adsorb catechins contained in the extract, and after the end of the flow of the extract. A caffeine comprising a washing step of washing caffeine, which is a methylxanthine contained in the extract by washing the chromatographic column with water, and an elution step of eluting the adsorbed catechins with an eluent. A method for producing catechins having a low content of in. 2. The caffeine extract according to claim 1, wherein the adsorbent is a carrier comprising a hydrophilic, macroporous acrylic three-dimensional crosslinked polymer and a cyclodextrin bonded thereto. For producing catechins containing catechins. 3. The amount of water used in the washing step is 2 to 10 in volume ratio with respect to the adsorbent.
2. A method for producing a catechin having a low content of caffeine according to item 1. 4. The method according to claim 1, wherein the eluent used in the elution step is one of methanol, ethanol and acetone solvents or an aqueous solution thereof having a low concentration of 80% to 30%. For producing catechins having low caffeine content. 5. The amount of the eluent used in the elution step is:
The method for producing a caffeine-low content catechin according to claim 1, wherein the volume ratio with respect to the adsorbent is 1 to 2.