JPH10290667A - Production of clear green tea beverage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a clear green tea beverage capable of preventing formation of turbidity without impairing characteristic taste of green tea. SOLUTION: This method for producing a clear green tea beverage comprises a green tea extracting process, a process for removing used tea leaves and a turbid component eliminating process. First, the green tea extracting process extracts green tea by boiling green tea leaves containing 5-50% of green tea leaves of the highest quality using warm water at 50-70 deg.C for 5-15 minutes. In the process for removing used tea leaves, the extracted solution of green tea is successively passed through a filter of 10-30 meshes and a filter of 100-200 meshes to remove used tea leaves from the extracted solution of green tea. In the final turbid component eliminating process, the extracted solution of green tea after the removal of used tea leaves is cooled to about 10 deg.C, centrifuged at a fixed velocity in a promoted state of precipitation of a turbid component to recover the objective cleared extracted solution of green tea.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a green tea beverage, and more particularly to a method for producing a clear green tea beverage from which turbid components are removed without impairing the flavor of green tea.

[0002]

2. Description of the Related Art In recent years, green tea beverages in which a green tea extract is filled in a can or a plastic container in a sealed container have been produced one after another. However, green tea beverages may lose flavor due to denaturation of contained components and may form turbidity such as suspended solids and sediment during long-term storage. Such turbidity can cause visual quality deterioration of the product, especially in the case of a product contained in a transparent container such as a plastic container.

[0003] In order to commercialize a green tea beverage, various methods have been developed to suppress the formation of this turbidity. The formation of turbidity such as suspended matters and precipitates is considered to be mainly caused by denaturation due to association of polymer components such as polyphenols. In addition, the flavor tends to be impaired with the formation of turbidity such as suspended matter and sediment. Therefore, these methods have been developed mainly from the viewpoint of how to remove this turbid component.

[0004] Specifically, as one of the methods, a method of filtering a green tea extract with an ultrafiltration membrane (JP-A-4-4574).
No. 4 publication). In the case of this method, although the formation of precipitates and the like is suppressed, there is a disadvantage that the flavor component of green tea is poor because the flavor component of green tea is removed by ultrafiltration.

Japanese Patent Application Laid-Open No. 4-31348 discloses a method in which green tea is quenched by acidification with ascorbic acid to promote the formation of precipitates, filtered by centrifugation or the like, and then filtered by adding diatomaceous earth for clarification. Is disclosed. But,
In the case of this method as well, although the formation of precipitates is suppressed, there is a problem that the flavor of green tea is denatured, which is considered to be caused by a sudden change in the pH of the solution.

Japanese Patent Application Laid-Open No. Hei 8-228684 discloses a method in which an enzyme treatment is carried out with hemicellulase. When such an enzyme treatment is used, green tea is added by adding a component other than green tea called an enzyme. There is a problem that the original flavor changes.

Further, a method comprising the steps of decomposing a polymer component by extracting an active ingredient from a tea raw material and adding an acid component to obtain an acidic tea extract, and a step of homogenizing the acidic tea extract under high pressure (particularly). No. Hei 7-170912). However, also in this method, there is a problem that the flavor of the finally obtained green tea extract is deteriorated because an acid or the like that can decompose the polymer component is added.

As described above, the conventional production method has a problem that the turbid component can be removed, but the original flavor of green tea cannot be maintained.

[0009] In view of the above problems, an object of the present invention is to provide a method for producing a clear green tea beverage from which turbid components have been removed without impairing the original flavor of green tea.

[0010]

In order to achieve the above object, a method for producing a clear green tea beverage according to the present invention comprises:
Green tea leaves containing 50% to 50% with warm water at 50 to 70 ° C
A green tea extraction step of extracting green tea brewed for 15 minutes, and after the green tea extraction step, a green tea extract is sequentially passed through a 10-30 mesh filter and a 100-200 mesh filter to remove tea husks from the green tea extract. The green tea extract after the step and the above-mentioned tea husk removing step is passed through a cooler and cooled to about 10 ° C., and after cooling, 5,000 rpm to 1
A turbid component removing step of separating and removing turbid components by performing centrifugation at a speed of 000 rpm.

That is, in the method for producing a clear green tea beverage of the present invention, green tea is extracted by extracting rich flavor of gyokuro using green tea leaves including gyokuro tea leaves. After the extraction of green tea, the green tea extract is sequentially filtered using a coarse filter and a fine filter to prevent clogging of the filter and quickly remove the tea husk. By quickly removing the tea husks in this way, it is possible to prevent the flavor and color tone from being deteriorated when the tea husks are mixed for a long time.

In the final turbid component removing step, the green tea extract is cooled to about 10 ° C. in advance and centrifuged at a predetermined speed in a state where precipitation of the turbid component is promoted, so that the flavor component of the green tea is removed. The turbid component is separated and removed while leaving.

Therefore, according to the method for producing a clarified green tea beverage of the present invention, a clarified green tea beverage which does not form turbidity without impairing the flavor of green tea can be produced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

1. Green Tea Extraction Step The green tea leaf used in the present invention may be any green tea leaf containing 5 to 50% gyokuro, and can be arbitrarily blended according to the flavor to be produced. By mixing the gyokuro tea leaves, a flavorful green tea extract can be obtained. Therefore, by increasing the amount of mixed gyokuro tea leaves, a richer flavor can be obtained from the green tea extract.

In order to extract green tea by infusing the green tea leaves blended in the above, it is carried out in hot water of 50 ° C. to 70 ° C. for 3 to 10 minutes. Green tea leaves other than Gyokuro tea leaves are 80 ℃ ～ 1
It is preferable to incense at 00 ° C, but when gyokuro tea leaves are contained, the flavor unique to gyokuro can be effectively extracted at a hot water temperature of 50 ° C to 70 ° C. Therefore, it is desirable to extract at a temperature suitable for the tea leaves blended above.

The amount of tea leaves to be used is 25 kg to 35 kg with respect to 1,000 liters of extracted hot water, and the amount of tea leaves can be appropriately increased or decreased according to the quality of the tea leaves and the like. The warm water to be used may be simple warm water, but in order to prevent a change in flavor due to oxidation during the operation, warm water subjected to an antioxidant treatment may be used. The hot water that has been subjected to the antioxidant treatment is, for example, hot water to which salts such as sodium ascorbate are appropriately added within a range that does not change the flavor, or hot water obtained by boiling the hot water or deaerated using a deaerator (a deaerator). Is mentioned.

2. Step of removing tea husks The step of removing tea husks from the green tea extract must be performed promptly in order to prevent a change in flavor or color tone due to the mixture of the tea husks. Therefore, it is desirable to perform the following two steps. That is, a step of filtering using a filter capable of separating large tea leaves in advance and a step of filtering using a filter capable of collecting remaining fine tea leaves are sequentially performed.

As a filter from which the above-mentioned large tea husks can be collected, specifically, a filter of about 10 to 30 mesh may be used. Further, as a filter capable of collecting fine tea leaves, a filter of about 100 to 200 mesh may be used. In this way, by separating large tea leaves in advance and then collecting the remaining fine tea leaves, the tea leaves can be quickly removed without causing clogging of the filter. Therefore, it is possible to prevent a change in flavor and a change in color tone caused by the mixture of tea husks for a long time.

3. Turbid component removal step The green tea extract from which the tea husks have been removed in the above is quickly cooled to about 10 ° C. by passing through a cooler such as a plate cooler. When the green tea extract is left at the temperature at the time of extraction, the oxidation reaction is likely to proceed, causing the flavor to be impaired. Therefore, it is preferable to first cool the green tea extract to suppress the progress of the oxidation reaction and the like. Also, here 10 ° C
By cooling to a degree, the turbid components contained in the green tea extract are easily precipitated in the centrifugal separation operation described later.

As the cooling unit, an existing cooling device such as a plate cooler can be arbitrarily selected and used. Here, when using a plate cooler,
As the refrigerant inside the plate cooler, chilled water of about 5 ° C. or antifreeze of 5 ° C. or less is used. When chilled water at about 5 ° C. is used, the flow rate of the green tea extract is adjusted, and the green tea extract is allowed to stay on the plate cooler for about 10 to 20 seconds, so that the temperature of the green tea extract is adjusted to the temperature at the time of extraction. 50-10
0 ° C. can be cooled to about 10 ° C. Then
Here, the cooled green tea extract is poured into a centrifuge, and the components causing turbidity are removed by centrifugation.

When performing centrifugation, 5,000 rpm
The centrifugation is performed at a rotation speed of m to 10,000 rpm. When a continuous centrifuge is used, the processing speed is adjusted from 8,000 liters / hour to 20,000 liters / hour at the above rotation speed.

Before the centrifugation operation, add 10 parts of green tea extract.
If the temperature is not cooled to about ° C, the turbid components cannot be sufficiently removed under the above-mentioned centrifugal separation conditions.

However, in the present embodiment, the green tea extract is cooled to about 10 ° C. before the centrifugation operation to easily precipitate turbid components. 2,000 liters / hour to 20,000 liters / hour) makes it possible to appropriately remove turbid components.

As described above, by adjusting the temperature of the green tea extract, it has become possible to efficiently separate and remove turbid components using a simple centrifuge. As a result, a green tea extract suitable for long-term storage can be obtained.

The clarified green tea extract thus obtained is filtered, if necessary, using a filter aid such as diatomaceous earth, and microfiltration having a mesh size of about 0.5 to 5 microns. Etc. can be performed.

By adding a compound having an antioxidant effect, such as ascorbic acid, to the clarified green tea extract obtained by the above operation, a green tea extract that can withstand storage for a longer period can be produced. . And then,
The pH of the green tea extract is adjusted to about 6.0 to 7.0 with baking soda, sodium ascorbate, sodium carbonate, or the like, and a green tea extract suitable for filling in a plastic container such as a can, bottle, or PET bottle is prepared. Obtainable.

Further, a series of steps in the present embodiment may be performed in a nitrogen stream to prevent oxidation of the green tea extract.

[0029]

EXAMPLES Next, the present invention will be specifically described based on examples and the like, but the present invention is not limited by the examples.

Example 1 A mixed tea leaf of 10 kg of gyokuro and 20 kg of sencha was mixed in 1,000 liters of hot water at 60 ° C. to which the amount of dissolved oxygen was reduced to 5 ppm or less using a deaerator and 1 ppm of sodium ascorbate was added for 6 minutes. Extract. Immediately after the extraction, in order to separate the tea extract and the tea husk, they are sequentially passed through a 20-mesh and 150-mesh wire mesh separator to separate the tea extract. The obtained extract is passed through a plate cooler using chilled water as a refrigerant.
After cooling to 0 ° C., centrifugation was performed at a flow rate of 8,000 liters / hour at a rotation speed of 6,000 rpm to obtain a clarified tea extract. The obtained green tea extract contains 5 times the amount of vitamin C obtained by adding water twice as much as the green tea extract.
Added at a concentration of 00 ppm, adjusted to pH 6.5 with sodium bicarbonate,
A green tea extract for container filling was obtained.

Example 2 A mixed tea leaf of 15 kg of gyokuro and 15 kg of sencha was added to 1,000 liters of 70 ° C. hot water to which the amount of dissolved oxygen was reduced to 5 ppm or less using a deaerator and 1 ppm of sodium ascorbate was added for 5 minutes. Extract. Immediately after the extraction, to separate the tea extract and the tea husk, the tea extract is separated while sequentially passing through a wire mesh separator of 20 mesh and 150 mesh to obtain a tea extract. The obtained extract is passed through a plate cooler using chilled water as a refrigerant,
After cooling to 10 ° C., centrifugation was performed at a flow rate of 10,000 liters / hour at a rotation speed of 6,000 rpm to obtain a clarified tea extract. The obtained green tea extract contains 5 times the amount of vitamin C obtained by adding water twice as much as the green tea extract.
Added at a concentration of 00 ppm, adjusted to pH 6.5 with sodium bicarbonate,
A green tea extract for container filling was obtained.

Comparative Example 1 A mixed tea leaf of 10 kg of gyokuro and 20 kg of sencha was extracted in 1,000 liters of warm water at 60 ° C. for 6 minutes. Immediately after the extraction, the tea extract is separated from the tea husk by passing it through a 150-mesh wire mesh separator to obtain a tea extract. The obtained extract is passed through a plate cooler using chilled water as a refrigerant, cooled to 10 ° C., and then centrifuged at a rotation speed of 6,000 rpm at a flow rate of 10,000 liters / hour to clarify. The obtained tea extract was obtained. The obtained green tea extract is the green tea extract 2
Vitamin C to which a double volume of water was added was added at a concentration of 500 ppm, and the pH was adjusted to 6.5 with sodium bicarbonate to obtain a green tea extract for a container.

Comparative Example 2 Mixed tea leaves of 10 kg of gyokuro and 20 kg of sencha are extracted for 6 minutes in 1,000 liters of hot water at 60 ° C. Immediately after the extraction, the tea extract is separated from the tea husk by passing it through a 150-mesh wire mesh separator to obtain a tea extract. The obtained extract was passed through a plate cooler and cooled to 30 ° C., and then centrifuged at a flow rate of 10,000 liters / hour at a rotation speed of 6,000 rpm to obtain a clarified tea extract. Was. The obtained green tea extract was added with a 500 ppm concentration of vitamin C obtained by adding twice the amount of water to the green tea extract, and the mixture was adjusted to pH 6.5 with sodium bicarbonate.
To obtain a green tea extract for container filling.

[Determination] The green tea extracts obtained in the above Examples and Comparative Examples were sealed in a PET bottle, stored at 30 ° C. for 3 months, and subjected to a sensory test by five panelists.

In the sensory test, the presence / absence of deterioration of flavor (taste, aroma), turbidity, sedimentation, etc. was determined and comprehensively evaluated.

[0036]

[Table 1]

[0037]

As described above, according to the method for producing a clarified green tea beverage of the present invention, a tea husk is quickly removed from a flavorful green tea extract to which the flavor of gyokuro has been added as a starting material, and furthermore, the method is simpler. Turbid components are efficiently separated and removed by centrifugation. As a result, in a series of steps, the green tea extract is not oxidized and does not impair the extracted rich flavor. Further, since the turbid component is reliably removed by centrifugation, the finally obtained green tea extract does not form a precipitate or turbid even when stored for a long period of time. for that reason,
According to the present invention, a clear green tea beverage suitable as a green tea beverage contained in a can or a plastic container can be manufactured.

Claims (1)

[Claims] 1. 50 green tea leaves containing 5 to 50% of gyokuro tea leaves
A green tea extraction step of extracting green tea by brewing for 5 to 15 minutes using warm water of ~ 70 ° C, After the green tea extraction step, the green tea extract is sequentially passed through a 10-30 mesh filter and a 100-200 mesh filter, A tea husk removing step of removing the tea husk from the green tea extract, and passing the green tea extract after the tea husk removing step through a cooler to cool to about 10 ° C .;
A turbid component removing step of separating and removing turbid components by centrifuging at a speed of 000 rpm.