JP5827799B2 - Production method of tea extract - Google Patents

Description

  The present invention relates to a technique of a method for producing a tea extract.

  Tea has long been popular as a favorite beverage, but in recent years, physiological effects such as antioxidant and blood cholesterol-lowering effects of catechins contained in tea have attracted attention. Container-packed beverages filled in bottles and the like have gained high support. However, beverages containing catechins at high concentrations have a strong bitterness and astringency so that more catechins can be ingested, so they try to reduce bitterness and astringency while containing catechins at high concentrations. The technology to do is desired.

  The catechins in tea include polymer catechins and non-polymer catechins. The main components of non-polymer catechins include epigallocatechin gallate, epigallocatechin, epicatechin gallate, epicatechin, etc., and minor components include catechin, gallocatechin, catechin gallate, gallocatechin gallate, etc. Is mentioned. The non-polymer catechins are classified into free catechins to which gallate groups are not bonded and gallate catechins (gallate-type catechins) to which gallate groups are bonded. The former include epicatechin, epigallocatechin, Catechin and gallocatechin correspond to the latter, and the latter include epigallocatechin gallate, epicatechin gallate, catechin gallate, and gallocatechin gallate. It is known that gallate type catechin has a strong bitter taste and astringency as compared with free type catechin.

  Various techniques for reducing the bitterness and astringency of tea extracts by reducing gallate catechins have been developed. For example, a method of hydrolyzing gallate catechin into free catechin and gallic acid by tannase treatment is known (Patent Documents 1 to 3).

  In order to reduce the acidity and taste of gallic acid produced in tannase treatment, a method of removing gallic acid with an anion exchange resin installed in the latter stage has also been proposed (Patent Document 4). The anion exchange resin needs to be used in a salt form due to the influence on the flavor and pH, but there is a limit to the removal of gallic acid because the adsorption ability of the salt form ion exchange resin is low.

  Furthermore, a method of selectively adsorbing gallate catechins by bringing polyvinyl polypyrrolidone and tea extract into contact with each other at a high temperature has been proposed (Patent Document 5). However, the proposed method has a drawback in that it is necessary to add a large amount of expensive polyvinyl polypyrrolidone, which increases the cost.

JP-A-3-133828 Japanese Patent Laid-Open No. 10-313784 JP 2004-321105 A JP 2007-195458 A Japanese Patent Application Laid-Open No. 2004-159597

  The objective of this invention is providing the manufacturing method of the tea extract which can reduce gallate type catechin.

The method for producing a tea extract of the present invention comprises a step of contacting a tea extract containing a gallate catechin with a weakly acidic cation exchange resin containing a functional group of a carboxylic acid, and subjecting the gallate catechin to an adsorption treatment. The matrix structure of the weakly acidic cation exchange resin is a copolymer of acrylic acid and divinylbenzene , and some of the functional groups of the weakly acidic cation exchange resin are in a salt form.

  According to the present invention, gallate catechins can be reduced.

It is a schematic diagram which shows an example of a structure of the tea extract manufacturing apparatus which concerns on this embodiment.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  FIG. 1 is a schematic diagram illustrating an example of a configuration of a tea extract manufacturing apparatus according to the present embodiment. The tea extract manufacturing apparatus 1 shown in FIG. 1 includes an inflow line 10, an exhaust line 12, a column 14 filled with a weakly acidic cation exchange resin containing a functional group of carboxylic acid, and a storage tank 16.

  As shown in FIG. 1, an inflow line 10 is connected to a supply port (not shown) of the column 14. One end of the discharge line 12 is connected to a discharge port (not shown) of the column 14, and the other end is connected to a supply port (not shown) of the storage tank 16.

  In the present embodiment, the tea extract is not particularly limited as long as it is a solution containing tea leaf components. For example, tea leaf extract such as green tea, oolong tea, black tea, or a concentrate thereof, commercially available catechin powder, commercially available powdered tea, etc. An aqueous solution obtained by dissolving

  The tea extract contains non-polymer catechins such as catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate. As described above, among non-polymer catechins, gallate-type catechins (gallate-type catechins) such as catechin gallate, gallocatechin gallate, epicatechin gallate, and epigallocatechin gallate are bitter and astringent ingredients such as astringency. It is.

  The tea extract is supplied from the inflow line 10 to the column 14, and the tea extract is brought into contact with a weakly acidic cation exchange resin containing a functional group of carboxylic acid. Since the weakly acidic cation exchange resin containing a functional group of carboxylic acid has a higher affinity with the gallate type catechin than the above-described free type catechin, the resin and the tea extract are brought into contact with each other, thereby making the resin Galate-type catechin is preferentially adsorbed on the surface. As a result, a tea extract (treatment liquid) having a low content of gallate catechin, which is a bitter and astringent component, and reduced bitterness and astringency is obtained. The obtained tea extract is discharged from the discharge line 12 and stored in the storage tank 16.

  With such a simple process, it is possible to obtain a tea extract with a low content of gallate-type catechin, which is a bitter astringent component, and the ion-exchange resin used in this embodiment is relatively inexpensive, so production This is very advantageous from the viewpoint of efficiency and manufacturing cost.

  As the weakly acidic cation exchange resin containing a functional group of carboxylic acid used in the present embodiment, a general-purpose resin generally used for industrial use can be used. For example, Amberlite FPC3500, IRC76, IRC86RF, Dowex MAC-3, manufactured by Dow Chemical Company, Diaion WK10, WK11, WK40, manufactured by Mitsubishi Chemical Corporation, Levatt S8528, S8229 manufactured by LANXESS, and the like. Weakly acidic cation exchange resins containing a carboxylic acid functional group are resins having a base structure of a methacrylic polymer such as a copolymer of methacrylic acid and divinylbenzene, and acrylics such as a copolymer of acrylic acid and divinylbenzene. There are resins having a polymer in the matrix structure. Among these, weakly acidic cation exchange resins having an acrylic polymer as a matrix structure tend to have a strong affinity for gallate catechins in particular, and thus gallate catechins can be efficiently removed. On the other hand, since the affinity with caffeine is weak, there is an advantage that the caffeine in the tea extract is prevented from being removed, and the flavor and the like of the obtained tea extract are not impaired. Examples of the weakly acidic cation exchange resin having an acrylic polymer as a matrix structure include Amberlite FPC3500, IRC76, IRC86RF, Diaion WK40, Levacit S8528, S8229, and the like.

  In this embodiment, the tea extract and the weakly acidic cation exchange resin are brought into contact with each other by the column system in which the tea extract is passed through the column 14 filled with the weakly acidic cation exchange resin. If the state which contacts weakly acidic cation exchange resin can be ensured, it will not necessarily restrict to this. As another form, you may make a tea extract and weakly acidic cation exchange resin contact by the batch system which adds weakly acidic cation exchange resin to a tea extract, for example. From the viewpoint of production efficiency and workability, the column method is preferable to the batch method.

When processing by the column system, for example, the SV (space velocity) is in the range of 0.5 to 30 (h ⁻¹ ), and the liquid flow rate is 1 to 30 times per packed volume of the weakly acidic cation exchange resin. It is preferable to pass the tea extract through the column 14.

  The temperature at which the tea extract and washing water are passed is not particularly limited, but is preferably less than 40 ° C, more preferably less than 25 ° C. For example, the adsorption efficiency of gallate catechins may be reduced when the temperature of the tea extract passing through is 40 ° C. or higher.

  The weakly acidic cation exchange resin packed in the column 14 is subjected to a regeneration process after the tea extraction liquid passing process is completed, and the adsorbed components such as gallate catechin are eluted from the resin layer. As the regenerant used in the present embodiment, a hydrophilic solvent such as ethanol or acetone and an aqueous solution thereof, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide, an aqueous acid solution such as hydrochloric acid or sulfuric acid, hot water, or the like is used. Can do. After eluting the adsorbed component with the regenerant, the ionic form of the weakly acidic cation exchange resin is adjusted using an acid solution or an alkali solution as necessary.

  The ion form of the weakly acidic cation exchange resin is not particularly limited, but it can be used in the hydrogen form. The tea extract in which the gallate catechin is reduced by the above hydrogen-type weakly acidic cation exchange resin tends to be acidic and strong in acidity. It is preferable to adjust. Although it does not specifically limit as an alkaline chemical | medical agent, For example, sodium hydrogencarbonate, sodium carbonate, sodium hydroxide etc. are mentioned.

  In addition, as a method of adjusting the pH of the tea extract with reduced gallate catechins, a part of the functional group of the weakly acidic cation exchange resin is previously salted, and the resin and the tea extract are used. The method of making it contact is mentioned. When a weakly acidic cation exchange resin having a salt-type functional group is used, the ions in the tea extract and the ions adsorbed on the resin are exchanged by ion exchange. The change in pH is reduced. Although it does not specifically limit as a functional group of a salt form, For example, a sodium form, a potassium form, a calcium form etc. are mentioned. As a method for converting a part of the functional group of the weak acid cation exchange resin into a salt form, for example, in the column system, an appropriate amount of an alkaline solution is applied to the column 14 packed with the weak acid cation exchange resin prepared in the hydrogen ion form. A method of converting a part of the functional group of the weakly acidic cation exchange resin into a salt form by passing the solution is mentioned. Thereafter, the resin is preferably washed with water and mixed so that the hydrogen-type resin and the resin converted into the salt form are uniform.

  The tea extract with reduced gallate catechins can also be made into a concentrate form by an appropriate concentration means. Moreover, the tea extract with reduced gallate type catechins can be dried by a drying means such as spray drying, vacuum drying, freeze drying, etc., to form a powder.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail more concretely, this invention is not limited to a following example.

Example 1
7000 g of ion-exchanged water was added to 56 g of green tea powder, stirred for 120 seconds, and then filtered through a filter (pore size 0.45 μm) to obtain a clear green tea extract. A glass column with a jacket (inner diameter: 22 mm × height: 1000 mm) was charged with 300 mL of a hydrogen ion-type acrylic weakly acidic cation exchange resin (AMBERLITE FPC3500, manufactured by Dow Chemical Co.) containing a functional group of carboxylic acid. A thermostat with a circulation function was connected to the column jacket to circulate 20 ° C. water, the temperature in the column was made constant, 6000 mL of the filtered green tea extract was adjusted to 20 ° C., and then passed through the column. SV at the time of liquid passing was set to 4 (h ^<-1> ). Of the processing liquid (tea extract) discharged from the column, 5500 mL, excluding the initial 500 mL, was recovered. Sodium bicarbonate powder was added to the collected treatment liquid to adjust the pH to 5.7.

( Reference example )
7000 g of ion-exchanged water was added to 56 g of green tea powder, stirred for 120 seconds, and then filtered through a filter (pore size 0.45 μm) to obtain a clear green tea extract. A glass column with a jacket (inner diameter 22 mm × height 1000 mm) was charged with 300 mL of hydrogen ion-type methacrylic weakly acidic cation exchange resin DIAION (Mitsubishi Chemical Corporation, WK11) containing a carboxylic acid functional group. A thermostat with a circulation function was connected to the column jacket to circulate 20 ° C. water, and the temperature inside the column was made constant. Then, 6000 mL of the filtered green tea extract was adjusted to 20 ° C. and then passed through the column. SV at the time of liquid passing was set to 4 (h ^<-1> ). Of the processing liquid (tea extract) discharged from the column, 5500 mL, excluding the initial 500 mL, was recovered. Sodium bicarbonate powder was added to the collected treatment liquid to adjust the pH to 5.7.

(Example 3)
7000 g of ion-exchanged water was added to 56 g of green tea powder, stirred for 120 seconds, and then filtered through a filter (pore size 0.45 μm) to obtain a clear green tea extract. A glass column with a jacket (inner diameter 22 mm × height 1000 mm) was charged with 300 mL of a hydrogen ion-type acrylic weakly acidic cation exchange resin (AMBERLITE FPC3500, manufactured by Dow Chemical Co.) containing a functional group of carboxylic acid. Next, 5 mL of 1N sodium hydroxide solution was added from the top of the column, and then 600 mL of ion-exchanged water was passed through. Next, ion exchange water was passed upward from the lower part of the column, the resin was allowed to flow for 10 minutes, and then the water flow was stopped to calm the resin. Subsequently, a thermostat with a circulation function was connected to the column jacket to circulate water at 20 ° C., and the temperature inside the column was made constant. Then, 6000 mL of the filtered green tea extract was adjusted to 20 ° C. and then passed through the column. Liquid. SV at the time of liquid passing was set to 4 (h ^<-1> ). Of the processing liquid (tea extract) discharged from the column, 5500 mL, excluding the initial 500 mL, was recovered.

Table 1 summarizes the pH, gallate body fraction, and sensory evaluation results of the untreated green tea extract and the treated solutions of Example 1 , Reference Example and Example 3.

The rate of gallate is catechin gallate, gallocatechin relative to the total weight of non-polymer catechins consisting of 8 types of catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate It is 100% of the sum of weights of gallate type catechins consisting of gallate, epicatechin gallate and epigallocatechin gallate.
Rate of gallate body = weight of four kinds of gallate catechins / weight of eight kinds of non-polymer catechins × 100

The weight of each component of the gallate-type catechin in the treatment liquid (tea extract) of Example 1 , Reference Example and Example 3 was measured by the following measurement method.

<Measurement method of catechin amount>
The sample was diluted with ion-exchanged water, filtered through a filter (pore size 0.45 μm), and then packed into a high performance liquid chromatography (LC-2000Plus series) manufactured by JASCO Corporation, a packed column for octadecyl group-introduced liquid chromatograph Shim-pack FC- An ODS (4.6 mmφ × 150 mm: manufactured by Shimadzu Corporation) was attached, the column temperature was set to 40 ° C., and measurement was performed using the gradient method under the following conditions.
Mobile phase A solution: 0.1 mol / liter phosphate buffer (pH 2.6)
Mobile phase B liquid: Acetonitrile injection amount: 10 μL
UV detection wavelength: 270 nm

  As is clear from Table 1, the gallate fraction of the tea extract obtained by treating the green tea extract with a weakly acidic cation exchange resin containing a carboxylic acid functional group is compared with that of the untreated green tea extract. It was falling. In particular, the gallate fraction of the tea extract obtained by treatment with an acrylic weakly acidic cation exchange resin based on a copolymer of acrylic acid and divinylbenzene is significantly higher than that of the untreated green tea extract. The bitter and astringent taste was clearly suppressed in the sensory evaluation.

  1 Tea extract manufacturing device, 10 inflow line, 12 discharge line, 14 columns, 16 storage tank.

Claims (1)

Contacting a tea extract containing a gallate-type catechin with a weakly acidic cation exchange resin containing a functional group of a carboxylic acid, and adsorbing the gallate-type catechin;
The matrix structure of the weakly acidic cation exchange resin is a copolymer of acrylic acid and divinylbenzene ,
A method for producing a tea extract, wherein a part of the functional groups of the weakly acidic cation exchange resin is in a salt form.

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