JP3072979B2 - Method for producing powdered teas and powdered teas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing powdered teas which can be drunk as tea by dissolving with water or hot water.

[0002]

2. Description of the Related Art Conventional powdered teas are manufactured as follows. Conventional methods for producing powdered teas are divided into three steps: a step of producing crude tea, a step of extracting a concentrated liquid from the crude tea, and a step of drying the extracted concentrated liquid.

First, in the process of producing crude tea, the extracted fresh tea leaves are steamed with saturated steam at about 100 ° C. to inactivate oxidative enzymes such as oxidase and peroxidase contained in the fresh tea leaves. After that, it is composed of the steps of coarse kneading, kneading, medium kneading, fine kneading, and drying.

[0004] In the next step for the crude tea produced by the above steps, after separating the crude tea into stems and leaves, various treatments such as roasting to impart flavor to the leaves are performed. The tea after the various treatments is extracted with water or hot water to obtain a concentrated liquid.

[0005] The concentrated solution is powdered by a known reduced pressure heating and concentration method. As described above, powdered teas are mainly manufactured through three steps.

[0006]

However, the conventional methods for producing powdered teas described above have the following problems. First, for example, Japanese Patent Publication No. Sho 62-15173,
JP-B-62-15174, JP-B-62-4489
No. 9, JP-B-63-42498, JP-B-3
As disclosed in JP 3649 or JP-A-5-236877, when hot water is used to extract components from tea leaves such as crude tea, useful components having no heat resistance such as ascorbic acid contained in the tea leaves are destroyed. There is a problem that. Japanese Patent Publication No. Sho 62-15173 and Japanese Patent Publication No. Sho 62-15
No. 174, JP-B-62-57290, JP-B-63-42498 or JP-A-5-236877.
When water is used to extract components from tea leaves such as crude tea, as disclosed in Japanese Patent Application Publication No. H10-163, since dextrinic acid and ascorbic acid are dissolved in water and an extraction solvent is used, non-contained tea leaves are used. There is a problem that water-soluble β-carotene and tocopherol are not extracted.

As disclosed in Japanese Patent Application Laid-Open No. 5-304890, a production method is also proposed in which a branched dextrin having a DE of 10 or less is added to an extract extracted from tea leaves and then spray-dried. In this case, the ability to retain the flavor component and the useful component was weak, and the flavor and the like could not be maintained for a long period of time.

[0008] The present invention has been made in view of the above circumstances, and provides a method for producing powdered teas containing more active ingredients and capable of maintaining flavor and the like for a long period of time. It is intended to provide.

[0009]

The method for producing powdered teas according to the present invention comprises a step of steaming fresh tea leaves, a step of grinding and pressing the tea leaves after this step, and a step of pressing the squeezed liquid obtained in this step. Has a step of ultrafiltration and concentration by reverse osmosis, and a step of adding cyclic dextrin to the concentrated liquid obtained in this step and drying.

The powdered teas according to the present invention are obtained by ultrafiltration of a squeezed liquid obtained by grinding and squeezing steamed fresh tea leaves, adding a cyclic dextrin to a concentrated liquid concentrated by reverse osmosis, and drying the concentrated liquid. It is a thing.

[0011]

FIG. 1 is a schematic flowchart showing the steps of a method for producing powdered teas according to an embodiment of the present invention.

[0012] The method for producing powdered teas according to the embodiment of the present invention comprises a step of steaming fresh tea leaves, a step of grinding and pressing the tea leaves after this step, and a step of limiting the pressed liquid obtained in this step. It comprises a step of external filtration and concentration by reverse osmosis, and a step of adding cyclic dextrin to the concentrate obtained in this step and drying.

First, raw tea leaves are steamed with saturated steam at about 100 ° C. using a general steaming device (S in FIG. 1).
2). By this steaming, the activity of oxidases such as peroxidase and oxidase contained in fresh tea leaves is lost. Also, the tea leaves become soft and soft due to the steaming heat. Further, the tea leaves are cooled. If this steaming is performed for about 30 to 40 seconds using saturated steam at about 100 °, 90% or more of the oxidases such as peroxidase and oxidase lose their activity.

The cooled tea leaves are ground by a suitable grinding machine (see S3 in FIG. 1). Examples of this suitable attritor include:
There is a cylindrical portion having teeth that are driven to rotate at high speed inside a cylindrical portion. That is, by introducing the tea leaves into the interior of the cylindrical portion, the tea leaves are ground between the inner peripheral surface of the cylindrical portion and the teeth,
Further, this is caused to collide with the inner peripheral surface of the cylindrical portion to grind more finely.

[0015] By this grinding, the cell membrane and the vacuolar membrane of the cells in the tea leaf are disrupted. The crushing of the cell membrane and the vacuolar membrane improves the efficiency of squeezing the useful components in the cells performed later. That is, in this grinding step, any grinding machine may be used, but it is important to use one that can break the cell membrane and vacuolar membrane of cells in tea leaves.

In this grinding step, it is also effective to add ethanol as a solvent. That is, by adding ethanol, tocopherol and the like, which are water-insoluble useful substances contained in tea leaves, can be extracted. For example, ethanol as a solvent is
About 20 to 30% is added to the steamed tea leaves. Needless to say, the solvent added here is harmless to humans and animals.

Next, the ground tea leaves are, for example, 165 kg.
/ Cm ² to obtain a pressed liquid (see S4 in FIG. 1). Since the squeezed liquid contains a high concentration of antioxidants such as catechins and ascorbic acid contained in tea leaves, it is possible to minimize the loss due to the breakdown of other components due to oxidation and the like.

The squeezed liquid is once frozen to form an insoluble cream (see S6 in FIG. 1). In addition, it is also possible to add, for example, ethanol as a solvent in the crushing step as well as in the crushing step, and to add ethanol only in the crushing step without adding ethanol in the crushing step. It is possible. In addition, the pressure at the time of squeezing is not limited to the said numerical value, 100-150
It can be appropriately selected between 0 Kg / cm ² .

Freezing the squeezed liquid once is effective in removing the insoluble cream, but is also effective in the following points. That is, the season when fresh tea leaves are collected is 4
From June to June, powdered teas can be produced regardless of the season if the squeezed liquid is frozen and stored at this time.

Further, ultrafiltration is performed on the squeezed liquid (see S7 in FIG. 1). This ultrafiltration has a large purpose of removing the insoluble cream, removing bacteria and impurities slightly contained in the squeezed liquid, and preventing furling in a concentration step performed following the ultrafiltration. I have. For example, this ultrafiltration is performed by an ultrafiltration membrane in which hollow fiber-shaped membranes are multiplexed.

The concentrations of amino acids and the like contained in the ultrafiltrate obtained by this ultrafiltration membrane and the squeezed liquid before ultrafiltration are as shown in Table 1 below. That is, it can be seen from Table 1 that the tannins constituting the insoluble cream are removed at a high rate by ultrafiltration.

[0022]

[Table 1] Unit (ppm)

The compressed liquid subjected to ultrafiltration, that is, the ultrafiltrate is concentrated by a reverse osmosis membrane device (S in FIG. 1).
9). Here, the material permeability of the reverse osmosis membrane is determined by the structure of the reverse osmosis membrane, the flow overpressure applied to the reverse osmosis membrane, and the like. Also, the main component of green tea umami has a molecular weight of 90-17.
The amino acids are around 0, and the main components of astringency and bitterness are catechins having a molecular weight of around 300 to 450. In particular, the molecular weight of epicaterenlate of catechins is 458, and the molecular weight of athenin, a typical component of the sweetness of green tea, is 119.2. The taste of the tea is determined by these contents and the content ratio. In other words, it is not an exaggeration to say that the taste of green tea depends on the balance between amino acids and catechins. Therefore, the reverse osmosis membrane affects the flavor of the powdered tea as the final product, and its selection is very important.

This concentration step is a non-heating step and is a step based on the action as a molecular sieve utilizing the difference between the molecular weight and the molecular structure of the components contained in the tea leaves.

For example, using a reverse osmosis membrane having an area of 200 cm ² having an ability to remove 95% or more of a substance having a molecular weight of 100 or less from the ultrafiltrate with a spiral type synthetic polymer composite membrane, Table 2 shows the results of pressurizing at ²⁰ to 30 kgf / cm ² and concentrating at a flow rate of 8000 cc / min for about 6 hours.

[0026]

[Table 2] Unit (ppm)

The following can be read from Table 2.
That is, by concentrating using a reverse osmosis membrane according to the above-mentioned specifications, the concentration became about 3.5 times for amino acids, about 3.4 times for tannins, and about 4.3 times for ascorbic acid. In particular, ascorbic acid lacking heat resistance was concentrated without disintegration. The concentration of each component in the waste liquid is extremely low and can be ignored.

By concentrating over a longer period of time,
A higher concentration of the concentrate can be obtained.

To the concentrate obtained through the concentration step, 0.01 to 0.5% (W / W) of cyclic dextrin as a powdered base material of the starch hydrolyzate is added and mixed. Since this cyclic dextrin has a cavity that is a hydrophobic region in the molecule, it includes non-aqueous components such as β-carotene and tocopherol. In addition, since the outer periphery of the cyclic dextrin is a hydrophilic region, it contains water-soluble amino acids, catechins, caffeine, ascorbic acid and the like to prevent loss of useful substances.

The mixture obtained by adding and mixing the cyclic dextrin is dried by a well-known technique such as spray drying or freeze drying to obtain a powder (see S11 in FIG. 1). This completes powdered teas that can be drunk as tea by dissolving with water or hot water. The powdered teas can be used not only as beverages but also as food additives utilizing the deodorizing action, antioxidant action, bactericidal action, and the like of tea. In addition, deodorants, antioxidants,
It can also be used as a bactericide.

According to the sensory test, 0.3% (W /
It was possible to obtain a result that the cyclic dextrin of the order of W) was suitable as powdered tea.

Table 3 shows the component contents of the powdered teas obtained by spray drying to which about 0.3% (W / W) of cyclic dextrin was added.

[0033]

[Table 3] Unit (mg / dry wt g)

In this way, powdered tea is produced.
It is also possible to add a powder obtained by instantaneously drying the steamed and squeezed tea leaves to a concentrated liquid (see S41 to S44 in FIG. 1). Tea leaves after squeezing
Although the active ingredient remains, it can not be used for other uses as it is, but it can be used effectively by pulverizing it and adding it to the concentrate, and powdered teas with higher active ingredients can do.

Further, tea leaves which have been crushed into fine powder can also be used as powdered tea.

[0036]

The method for producing powdered teas according to the present invention comprises a step of steaming fresh tea leaves, a step of grinding and pressing the tea leaves after this step, and an ultrafiltration of the pressed liquid obtained in this step. And a step of concentrating by reverse osmosis, and a step of adding cyclic dextrin to the concentrate obtained in this step and drying.

In the method for producing powdered teas, the steaming of the fresh tea leaves inactivates and swells and softens the oxidase contained in the fresh tea leaves, thereby improving the efficiency of the subsequent grinding step. I do. In addition, by grinding the tea leaves, cell membranes and the like are destroyed to improve the efficiency of pressing. further,
The concentration of flavor components and active ingredients can be increased by ultrafiltration and concentration by reverse osmosis. In addition, by adding cyclic dextrin to the concentrate, flavor components and the like can be included in the cyclic dextrin to prevent loss of active ingredients. Therefore, powdered teas produced by this production method have a large amount of active ingredients and can retain flavor and the like over a long period of time.

In the step of grinding and pressing the tea leaves, when a solvent is added during the grinding or pressing to dissolve the water-insoluble useful component in the pressed liquid, ascorbin is extracted as in hot water. There is no problem that the acid is disintegrated or that β-carotene, tocopherol and the like are not extracted as in the case of extraction with water. That is, the active ingredient can be effectively extracted.

In the step of concentrating by reverse osmosis, the content and ratio of flavor components and useful components in tea leaves are changed by a molecular sieve, so that the taste of powdered tea as a finished product is adjusted. It is possible to do.

Further, since the squeezed liquid is subjected to ultrafiltration after being frozen, the insoluble cream can be effectively removed and fresh powdered tea can be stored at any time by storing the frozen squeezed liquid. There is also an effect that a kind can be manufactured.

Further, the remaining tea leaves obtained by squeezing the squeezed liquid in the squeezing step are instantaneously dried, and then the finely powdered tea leaves are added to the concentrated liquid. It is possible to obtain powdered tea which is excellent and effectively utilizes the remaining tea leaves.

On the other hand, the powdered teas according to the present invention are obtained by ultrafiltration of a squeezed liquid obtained by grinding and squeezing steamed fresh tea leaves, and adding cyclic dextrin to the concentrated liquid concentrated by reverse osmosis. Since it is dried, it has more active ingredients than conventional ones, and can maintain flavor and the like for a long period of time.

The powdered teas obtained by adding the instantly dried and finely powdered remaining tea leaves squeezed from the squeezed liquid to the above-mentioned concentrated liquid and then drying the powdered teas have higher active ingredients and excellent flavor. Things.

[Brief description of the drawings]

FIG. 1 is a schematic flowchart showing steps of a method for producing powdered tea according to an embodiment of the present invention.

Claims (7)

(57) [Claims] 1. A step of steaming fresh tea leaves, a step of grinding and pressing the tea leaves after this step, a step of ultrafiltrating the pressed liquid obtained in this step and concentrating it by reverse osmosis; Adding a cyclic dextrin to the concentrated liquid obtained in the above, and drying the powder. 2. The powder according to claim 1, wherein in the step of grinding and pressing the tea leaves, a solvent is added at the time of grinding or pressing to dissolve a water-insoluble useful component in the pressed liquid. Tea production method. 3. The method for producing powdered teas according to claim 1, wherein in the step of concentrating by reverse osmosis, the content and ratio of flavor components and useful components in tea leaves are changed by a molecular sieve. 4. The method for producing powdered teas according to claim 1, wherein said compressed liquid is subjected to ultrafiltration after being frozen. 5. The method according to claim 1, further comprising a step of instantaneously drying the remaining tea leaves obtained by squeezing the squeezed liquid in the squeezing step, pulverizing the remaining tea leaves, adding the powder to the concentrated liquid, and then drying. The method for producing powdered teas according to claim 1. 6. Powdered tea obtained by grinding and squeezing steamed tea leaves and filtering the squeezed liquid obtained by ultrafiltration and adding cyclic dextrin to a concentrated liquid concentrated by reverse osmosis and drying. Kind. 7. Powdered teas which are obtained by adding a powder obtained by instantaneously drying and pulverizing the remaining tea leaves squeezed from a squeezed liquid to the concentrated liquid according to claim 6, and then drying.