JPH06296457A - Preparation of instant powdery tea - Google Patents

Abstract

PURPOSE:To prepare an instant powdery tea having excellent solubility and exhibiting the flavor, taste and appearance similar to those of common tea drink prepared by extracting tea leaves represented by green tea, GEMNAI-CHA (coarse green tea mixed with roasted popped rice), heated tea, oolong tea and black tea. CONSTITUTION:Liquid extracted from tea leaves is concentrated by reverse osmosis membrane treatment, powdery tea is added and mixed to the concentrate and the obtained mixture is frozen in a state containing air. The frozen product is graded and freeze-dried or freeze-dried and graded to obtain the objective instant powdery tea.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing instant powder tea which is excellent in solubility and has excellent flavor and taste.

[0002]

2. Description of the Related Art Conventionally, in the case of powdered tea and powdered coffee, raw materials such as tea leaves and coffee beans are put in an extraction tank or the like and extracted with boiling water or the like, and the extract is separated and then concentrated to an appropriate concentration. Alternatively, it was manufactured by adjusting the concentration with dextrin or the like and then drying it by spray drying or vacuum freeze drying. However, when pouring hot water into the above powder and drinking it, the one to which dextrin is added has a problem that a flavor different from the original flavor of tea and coffee is imparted, and the one dried by spray drying is tea. However, there was a flavor problem in that the aroma, which is the life of coffee, was weak, and a particularly light aroma was emitted.

Therefore, in order to solve these flavor problems, a method of concentrating the extract without using dextrin, or vacuum-freeze-drying the extract that has been previously concentrated to obtain a powder. Was thought. However, powder tea and coffee powder obtained by freezing the extract as it is and vacuum freeze-drying tend to cause lumps when pouring hot water into the powder,
To completely dissolve it, it was necessary to stir. Furthermore, when water was poured, it was almost insoluble even when stirred.

The present inventors have developed several techniques to solve these problems. For example, an instant powdered tea having excellent flavor and taste consisting of an extract obtained by extracting tea leaves with water, an extract obtained by distilling or solvent-extracting tea leaves and powdered tea leaves (JP-A-63-3755), and a solid content The method of incompletely vacuum-drying the contained aqueous solution, then subjecting it to dissolution treatment, and then again vacuum-freeze-drying to obtain an immediately soluble powder with improved solubility (JP-A-63-94960), solid content 5
A method for obtaining a high-quality and quick-dissolving powder by lyophilizing a flavored beverage at a content of not more than 5% by weight under vacuum, then biasing the dried product, then pulverizing the mixture by crushing, and sieving if necessary (JP-A-63-63 No. 167742). The present inventors have conducted further research on these techniques, and have developed a method for producing instant powder tea which is excellent in solubility and is excellent in flavor and taste.

[0005]

SUMMARY OF THE INVENTION The present invention is
A method for producing instant powder tea which has almost the same flavor, taste, and appearance as the tea that is extracted from the tea leaves represented by green tea, brown rice tea, houjicha, oolong tea, black tea, etc. with hot water and has excellent solubility. For the purpose of providing.

[0006]

The contents of the present invention will be described in detail below. First, an extract from tea leaves is obtained by a method in which water is added to tea leaves, followed by heat treatment and filtration, a method in which hot water is added to tea leaves and then filtration, and the like. In this case, relatively low temperature,
For example, it is preferable to extract at 10 to 40 ° C. As a result, bitterness and astringency components are not often extracted from tea leaves, and umami components can be effectively extracted.

After the extraction, the extract and the tea leaves are separated so that the tea leaves are not broken. For example, it may be carried out by a method such as pressing, squeezing or pressing. This makes it possible to prevent bitterness and elution of astringency components due to the collapse of tea leaves.

The extract thus obtained is concentrated by a reverse osmosis membrane. In the case of this reverse osmosis membrane concentration, there is an advantage that the flavor is not volatilized and the quality is less likely to be deteriorated by heat, but it is preferable to concentrate while suppressing the product temperature to about 25 ° C. The reverse osmosis membrane is concentrated while being subjected to cooling treatment.

In the concentration of the reverse osmosis membrane, the concentration of the solid content in the extract is 5% by weight or more, preferably 10 to 30% by weight. Concentration with a solid content concentration of about 5% by weight or less makes it difficult to freeze in air, which will be described later, or increases the time required for freeze-drying. Further, if the solid content concentration becomes too high, the solubility of the instant powder tea in the final product will become poor.

Tea leaf powder is added to and mixed with the concentrate thus obtained. The addition of the tea leaf powder is to enhance the taste and aroma of various teas and improve their appearance during drinking.

In order to obtain the tea leaf powder, various pulverizing methods can be adopted, but it is better to prevent deterioration of the quality of the tea leaves due to heat generated during pulverization as much as possible. It is preferable to employ a method of powdering tea leaves by the method described above.

The particle size of the tea leaf powder is 20 mesh pass, of which at least 50% by weight is 100 mesh pass. The amount of the powder used is preferably 0.1 to 20% by weight with respect to the instant powder tea which is the final product. If this amount is too small, it will be difficult to fully expect the effect of enhancing the taste and aroma of tea,
On the other hand, if the amount is too large, an unnatural feeling due to the tea leaf powder will appear.

The tea leaf powder may be added or mixed before or after the concentration of the extract, but from the viewpoint of preventing deterioration of the flavor of the tea leaves, it is preferable to add or mix the extract after concentration. In any case, it is desirable to carry out before the aerated freeze, and if it is added and mixed after that, it becomes difficult to uniformly disperse the tea leaf powder.

Thereafter, in the present invention, the above concentrated liquid is freeze-aerated, but before that, dimethyl sulfide may be added together with the tea leaf powder for the purpose of further enhancing the taste and aroma of tea. The amount of dimethyl sulfide added is 30 to 600 mg / 1 based on the final product.
The amount added is preferably 00 g, and if the amount added is too small, the effect of adding dimethyl sulfide cannot be expected so much. On the contrary, if the amount added is too large, the odor of dimethyl sulfide itself becomes too strong, which causes an unpleasant odor.

Next, when the concentrated solution is freeze-aerated, there are a method of mixing air bubbles at the time of freezing, a method of freezing the solution after it is aerated, and the like. Aeration and quick freezing at a temperature not higher than the boiling point of sulfide are preferable from the viewpoint of preventing volatilization of dimethyl sulfide. In addition, the freezing temperature is preferably below the complete freezing temperature, for example, below -30 ° C, and when this temperature is high, it may cause poor drying or foaming during vacuum freeze drying described later.

The method of mixing bubbles during freezing is not particularly limited, but for example, the concentration-adjusted extract can be cooled and frozen by contacting it with air or nitrogen gas using a scraping heat exchanger or the like. Good. Specifically, there is a method of freezing while mixing air bubbles with an ice creamer, which is an ice cream maker. As a method of aerating the concentrated liquid and then freezing, since the concentrated liquid has a certain degree of viscosity, it is possible to make the aeration necessary for the aerated freezing by vigorous stirring. Then, after aeration, it is rapidly frozen to maintain the aeration state.

The air content is 10 after the amount of bubbles after freezing.
It is preferable that the content be at least% by volume. When the amount of bubbles is less than 10% by volume, it is difficult to expect a sufficient effect in terms of easy solubility.

After freeze-drying the concentrated liquid in air, the particles are sized and then vacuum freeze-dried, or vacuum freeze-dried and then sized. The former method is suitable for obtaining coarse particles, and the latter method is suitable for obtaining fine particles. From the viewpoint of solubility, it is preferable to adopt the former method. On the other hand, in the case of the former method, when a fine powder is produced, the generation of the fine powder can be reduced as much as possible by recycling the fine powder to the concentrated solution concentrated by the reverse osmosis membrane.

As the former specific method, a method such as freezing and crushing in which air bubbles do not escape during sizing is carried out. If air bubbles escape during sizing, the solubility of the final product after vacuum freeze drying will decrease. The latter concrete method is not particularly limited and may be carried out in accordance with a conventional method.

[0020]

[Example 1] 7 kg of green tea leaves were mixed with 70 kg of water at 20 ° C
After the extraction treatment was performed for 0 minutes, the tea leaves and the extract were separated by a press-type pressing method so as not to break the tea leaves. The extract-insoluble solid matter thus obtained was removed by a continuous centrifuge to obtain 55 kg of an extract solution having a soluble solid content concentration of 2% by weight.
This extract was concentrated by the reverse osmosis membrane concentration method under the following treatment conditions.

The concentration treatment was carried out by setting a loose RO membrane NTR-759HR (membrane area 1.8 m ² ) in a membrane concentrator RUW-5 manufactured by Nitto Denko Corporation.

45 kg using 50 kg of the extract obtained above
It was dehydrated and concentrated to a solid content concentration of 20% by weight. After adding and mixing 5 g of 100-mesh-pass green tea powder to 500 g of this concentrated solution, a semi-frozen state with an air content of 45% by volume was made with a tabletop ice creamer manufactured by Aikosha, and the plate thickness was about 5 mm on an aluminum tray. And then completely frozen in a -40 ° C freezer.

Then, it was ground in a freezer at -40 ° C. by a roll type freezing and sizing machine and sieved to 7 to 32 mesh for sizing. The frozen sized product thus obtained was vacuumed to 10
Vacuum freeze-drying was carried out at a temperature of 30 ° C in Pascal and a drying time of 16 hours to obtain about 100 g of granular instant green tea powder having an acid content of 1.5% by weight.

The instant powder green tea thus obtained was put into a hot water cup, and when hot water was added to it, it quickly dissolved, and the flavor and taste were similar to those of green tea. In addition, a small amount of tea leaf powder was deposited on the bottom of the drinking tea, and the appearance was genuine.

[0025]

Example 2 Instant powder green tea was obtained in the same manner as in Example 1 except that 100 mg of dimethylsulfite was added to 20% by weight concentrate of the extract. The instant powder green tea thus obtained was superior in flavor and taste to that obtained by the method of Example 1.

[0026]

[Example 3] 10 kg of roasted leaves 60 kg of hot water at 40 ° C
After 30 minutes of extraction treatment, the tea leaves were separated from the extract with a basket-type centrifuge so as not to break the tea leaves. Therefore, the insoluble solid content of the extract obtained was 10 μm.
Removed with a filter of soluble solids concentration 2.5 end%
45 kg of the extract was obtained. 35 kg of this extract was dehydrated by the reverse osmosis membrane concentration method in the same manner as in Example 1 to concentrate the solid content concentration to 20% by weight.

To 500 g of this concentrated solution, 1 g of roasted green tea powder of 50 mesh pass was added and mixed, and then air-freezing, complete freezing, freeze sizing and vacuum freeze drying were carried out in the same manner as in Example 1 to obtain a water content of 2 100 g of instant powdered roasted green tea of 0.0% by weight was obtained.

The instant powdered hojicha thus obtained was placed in a hot water cup, and when hot water was added thereto, it immediately dissolved, and the flavor and taste were like hojicha. In addition, a small amount of tea leaf powder was deposited on the bottom of the drinking cup, and the appearance was genuine.

[0029]

Example 4 The concentrated green tea solution obtained in the same manner as in Example 1 was put into an aerated frozen state with an air content of 45% by volume, completely frozen on an aluminum tray, and vacuum freeze-dried as it was.
A dried product having a water content of 1.5% by weight was obtained. Then, this dried product was crushed with a crusher to a particle size of 20 mesh and sized to obtain instant powder green tea.

When the instant powder green tea thus obtained was placed in a hot water cup and hot water was added to it, the solubility was slightly inferior to that obtained by the method of Example 1, but it dissolved quickly with almost no problem. Also, the flavor and taste were similar to those of green tea. In addition, a small amount of tea leaf powder was deposited on the bottom of the drinking cup, and the appearance was genuine.

[0031]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to obtain an instant powdered tea which has almost the same flavor, taste and appearance as tea which is extracted from tea leaves with hot water and drunk on a daily basis. You can Then, by adding dimethylsulfite during the manufacturing process, the taste and flavor of tea can be further improved.

Claims (5)

[Claims] 1. A tea leaf extract is concentrated by a reverse osmosis membrane, and tea leaf powder is added thereto and mixed, and the resulting mixture is aerated and frozen, and then lyophilized after sizing or frozen. A method for producing instant powder tea, which comprises sizing after drying. 2. The concentration of the solid content of the extract is adjusted to 10 to 30% by weight by the concentration of reverse osmosis membrane.
A method for producing the instant powder tea described. 3. The tea leaf powder has a particle size of 20 mesh pass,
The method for producing instant powder tea according to claim 1, characterized in that at least 50% by weight thereof has a particle size of 100 mesh pass. 4. The method for producing instant powder tea according to claim 1, wherein dimethyl sulfide is added. 5. The method for producing instant powder tea according to claim 1, wherein the amount of dimethyl sulfide added is 30 to 600 mg / 100 g based on the final product.