JPH1156241A - Production of tea drink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable easy mass-production of a clear tea drink having excellent taste and flavor and free from the trouble of the precipitation of flocks by the lapse of time after production, by adding sodium ascorbate to an extraction stock liquid of tea leaf and subjecting the liquid to precision filtration in nitro gen atmosphere by cross-flow method. SOLUTION: Sodium ascorbate is added to an extraction stock liquid of tea leaf in an amount of >=0.015 g and <0.04 g based on 1 g of the tea leaf. The obtained liquid is separated into a concentrated liquid and a filtrate by treating the liquid with a precision filtration membrane by cross-flow method in nitrogen gas atmosphere. Further, the concentrated liquid is circulated and the filtrate is taken out of the system in nitrogen gas atmosphere. The pressure of the nitrogen gas is preferably 0.5-1.4 kg/cm<2> .

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 a tea beverage having a clear flavor which can be stored for a long time without causing turbidity or sediment, using tea as a raw material.

[0002]

2. Description of the Related Art A hot water extract from green tea is subjected to filtration or centrifugation using various filter agents to remove turbidity, and then filled in a metal can and sterilized.
The use of green tea beverages filled in containers made of paper, glass, or synthetic resin has recently attracted attention due to its simplicity.

[0003] In this green tea beverage, tea leaves are immersed in warm water at 40 to 100 ° C for 1 to 10 minutes, during which stirring is performed at a slow speed as needed to obtain an extract, and then the tea shell is separated and then centrifuged. Separation method, filtration using a metal filter, or pressure filtration method using filtration pulp to obtain a green tea liquor, after adding ascorbic acid or sodium ascorbate as an antioxidant to the green tea liquor, and then using sodium carbonate. It was manufactured by adjusting the pH.

[0004]

However, the green tea beverage obtained in this manner has a problem that floc precipitates as time passes after production. Since the floc continues even after long-term storage, even if the floc that has temporarily precipitated is separated, the floc is subsequently re-precipitated and the green tea beverage is turbid.

[0005] Therefore, it is impossible to produce a clear green tea beverage and maintain its quality for a long time by the conventional production method. It is thought that floc precipitation occurs when tannins, proteins, sugars, and the like, which are components of tea leaves, combine with the fine particles in the extract as nuclei during long-term storage. An object of the present invention is to provide a method for producing a tea beverage using sodium ascorbate under a nitrogen atmosphere in order to solve the drawbacks of the conventional floc precipitation and easily mass produce a green tea beverage having a clear and excellent flavor. The purpose is to do.

[0006]

The present invention comprises a step of adding sodium ascorbate to a stock solution from which tea leaves have been extracted;
A step of treating the liquid under a nitrogen gas condition in a cross-flow method using a microfiltration membrane to separate the concentrate into a permeate, a step of circulating the concentrate under a nitrogen gas condition, and a step of removing the permeate And a method for producing a tea beverage.

Preferably, the nitrogen gas condition is 0.5 to 1.4 kg.
/ cm ² . Preferably, sodium ascorbate is added in an amount of 0.015 g or more and less than 0.03 g per 1 g of tea leaves. If the nitrogen gas content is less than 0.5 kg / cm ² , quality deterioration during the manufacturing process cannot be sufficiently suppressed. If the amount is 0.04 g or more, the flavor of green tea is impaired.

[0008] For filtration of the stock solution, a microfiltration membrane is used in a cross flow system. The use of an ultrafiltration membrane is also conceivable, but a microfiltration membrane having a low pressure resistance is superior in preventing floc deposition and maintaining the flavor of tea leaves. As a filtration method,
There are a cross-flow method and a dead-end method, but the present invention uses the cross-flow method. The cross flow method is
In this method, liquid flows in a direction parallel to the filtration surface and a part of the stock solution is filtered.When the stock solution is sent to the membrane module for filtration, it is separated into a filtrate and a concentrate, and the concentrate returns to the stock tank. , Again sent to the filtration membrane module. The advantage of this method is that the liquid is in a direction parallel to the filtration surface, so that filtration can be performed without blocking the filtration surface. On the other hand, in the dead end method, since the flow is applied in a direction perpendicular to the filtration surface and the entire amount is filtered, the entire amount can be filtered, but there is a disadvantage that the filtration surface is blocked.

[0009]

The present invention will be described below with reference to examples. Example 100 g of green tea leaves having a high amino acid content was extracted in 4 liters of hot water at 70 ° C. for 4 minutes, and then the tea husk was removed. After the extract was cooled to 30 ° C., it was subjected to centrifugal separation, and sodium ascorbate was added in an amount of 0.02 g per 1 g of tea leaves and stored in a stock solution tank. Pump the undiluted solution from the undiluted solution tank to the membrane module using a microfiltration membrane made of fluororesin,
Cross-flow filtration was performed. In this filtration step, the atmosphere in the apparatus was replaced with nitrogen to separate into a membrane permeate and a concentrate. The concentrate was returned to the stock tank. The nitrogen pressure in the apparatus including the stock solution tank was maintained at 1.0 kg / cm ² . The obtained membrane-permeated liquid had an excellent clear flavor even after being processed as a green tea beverage, and its quality was maintained even after long-term storage of about one year.

Next, an experiment was conducted by changing the above-mentioned sodium ascorbate and the nitrogen pressure, and the degree of browning after the production (Table 1)
The results are shown in the following table for the retention of the original flavor (Table 2).

[0011]

[Table 1]

[0012]

[Table 2] From the table, the browning prevention of tea beverage, not preferred when not added ascorbic acid in less than 0.5 kg / cm ² nitrogen pressure,
Even in a nitrogen atmosphere, if the amount of ascorbic acid added is 0.04 g or more, the flavor is impaired, and if it is 0.014 g or less, the flavor cannot be sufficiently maintained, which is not preferable. Therefore, the nitrogen pressure is 0.5 kg / cm ²
As mentioned above, the amount of ascorbic acid added per 1 g of tea leaves
When the content is 0.015 g or more and less than 0.04 g, an original green tea beverage having an excellent clear flavor can be obtained.

[0013]

According to the present invention, various types of microfiltration membranes can be used for performing microfiltration in a low-pressure nitrogen atmosphere in the presence of a small amount of sodium ascorbate. You can get a drink.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Wataru Nosaka 1-25-10 Ekoda, Nakano-ku, Tokyo Shonan fragrance Co., Ltd.

Claims (3)

[Claims] 1. A step of adding sodium ascorbate to a stock solution from which tea leaves have been extracted, and a step of treating the solution under a nitrogen gas condition by a cross-flow method using a microfiltration membrane to separate it into a concentrate and a permeate. And a step of circulating the concentrated liquid under nitrogen gas conditions, and a step of extracting the permeated liquid. 2. The method according to claim 1, wherein the nitrogen gas condition is 0.5 kg / cm ² or more. 3. The method according to claim 1, wherein sodium ascorbate is added in an amount of 0.015 g or more and less than 0.04 g per 1 g of tea leaves.