JPH03277236A - Production of green tea product not causing turbidity - Google Patents

Abstract

PURPOSE:To prevent turbidity and precipitation occurring in cooling and preservation of tea product, by adding an alkaline (earth) metal hydroxide to a solution of tea. CONSTITUTION:Tea leaves are extracted with water containing >=0.4 pt.wt. calculated as hydroxyl group of alkaline (earth) metal hydroxide (e.g. NaOH) based on 100 pts.wt. solid content of tea solution at 55-95 deg.C or the alkaline (earth) metal hydroxide is added to the tea solution, filtered, then optionally mixed with an additive such as sweetener or lemon juice and cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing tea products that can prevent turbidity and precipitation that occur when tea products are cooled and stored.

<Prior Art> Generally, as tea products, transparent black tea, green tea, oolong tea, etc., such as canned or bottled lemon tea and straight tea, are known. Among these, for example, black tea products are manufactured by extracting black tea with hot water, filtering it, and mixing it with sweeteners and the like. In the manufacturing process of these transparent tea products, we are trying to prevent the turbidity and sedimentation that occurs when the products are kept cold.

How to prevent this is a major and long-standing issue. It is widely known that the turbidity and precipitation observed in the above tea products upon cooling are caused by the interaction between caffeine and tannins contained in the tea solution.

Therefore, as methods to suppress this turbidity, there are methods such as extraction by adding excessive sydic sugar, extraction by raising the pH using a pH adjuster, enzymatic treatment with tannase, etc., and extraction after cooling the extract. A method of mechanically separating the turbidity as a precipitate by strengthening the culm, or a method of adsorbing and removing tannins by contacting with a polymer resin, silica gel, etc., have been proposed.

However, shi! II! The method of extracting by adding excessive amount of water requires addition of 20% by weight or more to be effective, which is too sweet in terms of flavor and is not practical. The method of extraction using a large amount of addition gives a salty taste, which is undesirable in terms of flavor, and is ineffective at low addition amounts.Furthermore, it requires pH control in a very narrow slope, which is not preferable in terms of the process. . Further tannase treatment.

Methods such as over-strengthening and adsorption and removal of tannins not only complicate the process and increase raw material costs, but also have the problem of impairing the original flavor of tea. The reality is that no method of preventing turbidity has been found that takes this into account.

<Problems to be Solved by the Invention> The present invention was made in view of the above circumstances, and its purpose is to solve the problem of cloudiness during cooling and cold storage.

We have developed a method for producing tea products that not only prevents precipitation, but also has a desirable flavor and color tone, without reducing the content of caffeine tannins, which enhances the original flavor of tea, and without causing structural changes in the composition. It is about providing.

<Means for solving the problem> The above purpose is to extract tea from tea leaves and produce tea products by extracting an alkali of 0.4 parts by weight or more in terms of hydroxyl groups per 100 parts by weight of solids in the tea solution. Achieved by a method for producing tea products that does not produce turbidity, which is characterized by adding a metal or alkaline earth metal hydroxide to the hot water used for extraction in advance, or to the tea solution after extraction. Ru.

That is, the present inventor has discovered that hydroxides of alkali metals or alkaline earth metals having hydroxyl groups that have the effect of suppressing the formation of complexes between caffeine and tannins that cause turbidity, metal hydroxides, etc. It is written as an oxide. ) was found to suppress the turbidity of the tea solution, and the present invention was completed.

Next, the present invention will be explained in detail.

The tea products of the present invention include black teas such as lemon tea and straight tea, green teas, oolong teas, etc., and contain caffeine and tannins.

The manufacturing method of the present invention is carried out as follows.

Specifically, in the process of extracting tea from tea leaves, metal hydroxide is mixed with hot water in advance, tea is extracted using the aqueous solution, and after filtering, sweeteners, Raw materials such as lemon juice are added and cooled to obtain a tea product.

The extraction temperature of the above-mentioned tea is preferably in the range of 55 to 95°C. If the temperature is lower than 55°C, the bitterness and astringency of tea leaves tends to be slightly lacking. On the other hand, at high temperatures exceeding 95°C, a significantly large amount of bitter and astringent components are melted out, which may cause problems in terms of flavor.

Alternatively, instead of the hot water used for extraction, tea may be extracted from tea leaves with hot water, and the metal hydroxide may be added to the resulting tea solution. In this case, metal hydroxides may be added to the tea solution after extracting tea from tea leaves and filtering, or metal hydroxides may be added when adding other raw materials to the tea solution. good.

In addition, in the manufacturing method of adding a metal hydroxide to the extracted tea solution, the metal hydroxide is added before the tea solution is kept cold.

By adding metal hydroxide to hot water and tea solution during tea extraction, hydrogen bonds, which are thought to be the main factor in the interaction between caffeine and tannins, which causes cloudiness in tea products, are created. It is believed that the addition of metal hydroxides can suppress the formation of complexes between caffeine and tannins, and prevent turbidity and precipitation. This is preferable because it has a greater turbidity prevention effect and has no effect of metal hydroxide on the flavor of tea products.

Examples of the metal hydroxide used in the present invention include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkaline earth metal hydroxides such as aluminum hydroxide and magnesium hydroxide.

Among them, sodium hydroxide and potassium hydroxide are preferred. These may be used alone or in combination.

Conventionally, it has been reported that adding a pHjIl adjuster to raise the pH and extracting it is effective in reducing the cloudiness of black tea, but this is due to the flavor and process (there is a hassle in adjusting the pH to the appropriate level). Not very desirable.

However, in the present invention, the proper pH does not matter, and cloudiness of black tea can be suppressed by adding a small amount of electrolyte, whether it is a strong electrolyte or a weak electrolyte.

In addition, the amount of metal hydroxide added is 10% of the solid content in the tea solution.
It is necessary to set the amount to 0.4 parts by weight or more in terms of hydroxyl group compared to 0 parts by weight. If the amount added is less than 0.4 parts, turbidity and precipitation cannot be prevented. In addition, when adding metal hydroxide to the hot water during extraction, it is desirable to add 1.0 parts by weight or more of the metal hydroxide, and the amount added should be determined based on the tea solution after extraction. Calculate and determine the solid content in advance.

<Effects of the Invention> As described above, in the method for producing tea products of the present invention, turbidity and precipitation of the tea solution during cooling storage can be prevented by the simple method of adding metal hydroxide in the extraction and blending steps. can do.

Further, the production method of the present invention does not reduce the content of caffeine and tannins that control the original flavor of tea, and does not cause deterioration of the original flavor of tea.

Next, the present invention will be specifically described with reference to Examples.

<Examples 1 to 5. Comparative Example 1> The metal hydroxides listed in Table 1 were added to a black tea solution with a solid content of 100%.
1000 mj2 of a 90″C aqueous solution dissolved so that the amount is 0.4 part by weight or 1.0 part by weight based on the weight part
was used to extract 120 g of black tea.

Thereafter, it was cooled to 30°C, filtered in two stages with a 150+20 mesh filter, and kept cold at 5°C for 72 hours, after which the flavor and turbidity were visually evaluated.

The results are also shown in Table 1. As a comparative example, a sample without additives was evaluated.

<Example 6> 20g of black tea leaves using 1000mj2 of 90″C hot water
was extracted. After that, cool to 30°C and heat to 150+20
After passing through a two-stage sieve filter and aging for 5 minutes, sodium hydroxide was added to the black tea solution in an amount of 0.4 parts by weight per 100 parts by weight of solids in the black tea solution. After cooling at 5°C for 2 hours, the flavor and visual turbidity were determined. Based on the results in Table 1, by adding metal hydroxide,
It can be seen that it is possible to prevent tea from becoming cloudy.

Furthermore, when sodium hydroxide or potassium hydroxide was added to the hot water used for extraction, it was particularly effective in preventing turbidity.

Claims (1)

[Claims] When extracting tea from tea leaves and manufacturing tea products, 0.4 in terms of hydroxyl group per 100 parts by weight of solid content in the tea solution.
A tea product that does not produce turbidity, characterized in that at least part by weight of an alkali metal or alkaline earth metal hydroxide is added in advance to the hot water used for extraction, or added to the tea solution after extraction. Production method.