JP2006121973A - Unfermented tea with less caffeine and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain unfermented tea from which caffeine is selectively removed while sustaining catechin, and to provide a method for producing the tea. <P>SOLUTION: The unfermented tea with less caffeine is obtained by (1) the method including a process of boiling raw green tea leaves in an acid solution. Alternatively, the tea is obtained by (2) the method including a process of steaming raw green tea leaves and a process of washing the tea leaves thus obtained in an acid solution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an unfermented tea with less caffeine and a method for producing the same.

  As an effect ingredient of green tea, the anti-obesity effect of green tea catechin has attracted attention. Up to now, catechin was said to be effective in anti-aging, anti-allergy, etc. due to its high anti-oxidant ability, but anti-obesity, especially the effect of reducing triglycerides, has attracted attention, and young people who drink green tea for catechin intake Women and men are increasing. However, because caffeine contained in green tea has effects such as central nervous excitement and gastric acid secretion promotion, the effect of nerve excitement is attracting attention, but excessive intake makes the nerve excessively excited and makes it difficult to sleep or get angry. There have been reports of adverse effects such as becoming irritated.

  Conventional green tea contains 13% green tea catechins and 2.3% caffeine, and there is a problem that the intake of caffeine increases when a large amount of catechin is consumed. As an example, consider the effect of improving body fat metabolism. In order to improve fat metabolism in the body and reduce body fat, it is necessary to take 540 mg of green tea catechins a day, but 150 mg of caffeine is taken at the same time of taking that amount of catechins. Will be. This 150 mg amount of caffeine is an amount that adversely affects the nerves. Therefore, in order to bring out the benefits of green tea and increase the daily intake of green tea, a tea rich in catechins is desired for a small amount of caffeine.

  In addition, sales of tea-based drinks have increased greatly in recent years, but tea-based drinks are basically produced by extracting with hot water, then cooled and distributed at room temperature. Therefore, it is known that both caffeine and catechin dissolved at the time of production decrease in solubility upon cooling, or precipitate by forming a complex of both by reaction. This is called “Ori” and is avoided in transparent plastic bottles. Therefore, for this reason, it is considered necessary to reduce the amount of caffeine while maintaining the amount of tea catechins.

  In general, unfermented tea is produced by applying heat to fresh leaves to kill the enzymes in the fresh leaves and then drying them while squeezing. Two methods of “steaming” and “sautéing” have been put to practical use to inactivate enzymes in fresh leaves by applying heat to fresh leaves, and the other method is known as “warm with hot water”. Yes. Only “steaming” or “sauting” fresh leaves can inactivate enzymes in green tea, but cannot change the component content in green tea. However, it is known that when blue is killed by the “warm with hot water” method, caffeine decreases due to the difference in solubility depending on the temperature of caffeine and catechin. However, since both caffeine and catechin are difficult to dissolve in water and oil, it is difficult to remove caffeine only by the difference in solubility depending on temperature, and it is necessary to improve the equipment. The method is not universal.

In view of the above circumstances, an object of the present invention is to provide a non-fermented tea from which caffeine is selectively removed while maintaining catechin, and a method for producing the same.
In addition, tea attracts attention for the functionality of green tea catechins contained in the leaves, and has attracted attention not only as a taste drink but also as a functional drink. Today, demand and consumption of functional beverages are increasing, and it is desirable to remove caffeine that adversely affects functionality.

As a result of repeated studies by the inventor in order to solve the above problems, the present inventors have found the following and completed the present invention.
a) Catechin and caffeine are amphoteric substances that are hardly soluble in water and oil, but their water solubility can be adjusted by controlling the pH of the aqueous solution. For example, since catechin is an acidic substance, it is easily dissolved in an alkaline aqueous solution, and caffeine is an alkaline substance and is easily dissolved in an acidic aqueous solution.

b) Even though ordinary tea leaves are washed with an acidic solution, caffeine does not dissolve and decrease, but once steamed tea leaves are washed with an acidic solution, caffeine dissolves and caffeine in the tea leaves is lost. Decrease. Alternatively, when the tea leaf is boiled in an acidic solution to inactivate the enzyme in the tea leaf, caffeine dissolves and the caffeine in the tea leaf decreases.
c) Although the chlorophyll decomposes and discolors the tea leaves to which the acidic solution is adhered by the treatment with the acidic solution, discoloration of the tea leaves can be suppressed by washing with water or neutralization.

Based on the above discovery, the present invention provides the following means.
(1) An unfermented tea with less caffeine obtained by a method comprising a step of boiling green tea leaves in an acidic solution.
(2) boiling green tea leaves in an acidic solution;
A non-fermented tea with less caffeine, which is obtained by a method comprising a step of washing the tea leaves obtained by the above-mentioned step with water.
(3) boiling green tea leaves in an acidic solution;
A non-fermented tea with less caffeine, which is obtained by a method comprising a step of neutralizing tea leaves obtained by the above step with an alkaline fluid.

(4) The process of steaming fresh green tea leaves,
A non-fermented tea with less caffeine, which is obtained by a method comprising a step of washing the tea leaves obtained by the above step with an acidic solution.
(5) Steaming fresh green tea leaves;
Washing the tea leaves obtained by the above step with an acidic solution;
A non-fermented tea with less caffeine, obtained by a method comprising a step of washing the washed tea leaves with water.
(6) Steaming green tea leaves
Washing the tea leaves obtained by the above step with an acidic solution;
A non-fermented tea with less caffeine obtained by a method comprising a step of neutralizing the washed tea leaves with an alkaline fluid.

(7) A method for producing unfermented tea with less caffeine, comprising a step of boiling green tea leaves in an acidic solution.
(8) boiling green tea leaves in an acidic solution;
A method for producing unfermented tea with less caffeine, comprising washing the tea leaves obtained in the above step with water or neutralizing the tea leaves obtained in the above step with an alkaline fluid.

(9) Steaming the green leaves of green tea;
A method for producing unfermented tea with less caffeine, comprising a step of washing the tea leaves obtained by the above step with an acidic solution.
(10) Steaming green tea leaves
Washing the tea leaves obtained by the above step with an acidic solution;
A method for producing unfermented tea with less caffeine, comprising washing the washed tea leaves with water or neutralizing the washed tea leaves with an alkaline fluid.

  By boiling tea leaves with an acidic solution according to the present invention, it is possible to selectively remove caffeine from tea leaves rather than boiling with normal hot water. Thereby, it is possible to produce unfermented tea from which caffeine has been selectively removed while retaining catechins derived from tea leaves. Furthermore, it is possible to suppress discoloration of the tea leaves due to the acidic solution by washing the acidic solution adhering to the tea leaves with water or neutralizing with an alkaline water.

  Moreover, it is possible to selectively remove caffeine from tea leaves by immersing the tea leaves that have been steamed according to the present invention in an acidic solution. Thereby, it is possible to produce unfermented tea from which caffeine has been selectively removed while retaining catechins derived from tea leaves. Furthermore, it is possible to suppress discoloration of the tea leaves due to the acidic solution by washing the acidic solution adhering to the tea leaves with water or neutralizing with an alkaline water.

Hereinafter, the non-fermented tea with less caffeine of the present invention will be described in detail by its production method.
The tea leaves used as the raw material for the unfermented tea with a low amount of caffeine of the present invention can be any raw leaves as long as they are raw leaves used as the raw material for green tea.

According to one aspect of the present invention, the low-caffeine unfermented tea of the present invention is made by a method comprising a step of boiling green tea leaves in an acidic solution.
In the present invention, the “acidic solution” is a solution having a pH of 1 to 7, and preferably a solution having a pH of 2 to 5. The “acidic solution” is an acid that acts as an acid for caffeine and forms a water-soluble salt with caffeine. Any solution of any compound can be used as long as it can be used for food. . Examples of “acidic solutions” include organic acid solutions, inorganic acid solutions, and salts thereof.

  Examples of the organic acid solution include acetic acid, carbonic acid, citric acid, ascorbic acid, gluconic acid, malic acid and the like, and mixed solutions thereof; solutions of their salts that can be used as food processing aids or food additives As well as acidic solutions that can be used as food (eg vinegar). The pH of the organic acid solution may be adjusted by bringing it into a salt state. In addition, a solution of an organic compound that exhibits acidity when dissolved in water, such as glucnodelta lactone, can also be used in the present invention.

  Examples of the inorganic acid solution include a solution of hydrochloric acid, phosphoric acid, polyphosphoric acid, and the like, and a salt solution that can be used as a food processing aid or food additive. The pH of the inorganic acid solution can be adjusted by adding a basic compound such as arginine or the salt of the aforementioned organic acid. Further, it is desirable to use highly volatile acetic acid, hydrochloric acid, carbonic acid, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, or the like as the acidic solution because the need for a subsequent water washing operation is reduced.

  As the “acidic solution”, acidic water obtained by electrically decomposing water in which an edible salt (a substance in which an acidic substance and a basic substance are combined) is dissolved can also be used.

  Since the caffeine removal ability varies depending on the concentration and buffer capacity of the acidic solution, it is desirable to appropriately set the type, concentration and pH of the acidic solution to be employed. Concerning the concentration of the acidic solution, the acidic substance in the acidic solution can remove caffeine by reacting with caffeine 1: 1 to form a water-soluble salt, so it is specified by the amount of acid (molar amount). Is done. That is, the acid more than the amount of caffeine to be removed on a molar basis is required. However, since the reactivity is not 100%, caffeine can be removed only about 20% when the same amount of acid as caffeine is used. Also, as the acid concentration increases, the amount of caffeine that can be removed increases, but the reactivity tends to decrease, so the amount of acid used does not necessarily match the caffeine removal ability. Taking these into consideration, an acid content of the same amount to about 10 times the amount of caffeine to be removed is preferable. For example, when 100 g of green tea leaves are boiled, about 2.6 g (= about 0.013 mol) of caffeine is contained in 100 g of green tea leaves, so if it is an acidic solution of a monovalent acid, 0.013 mol An acidic solution having an acid content of ˜0.13 mol can be used. Here, when 10 L of acidic solution is used to boil 100 g of fresh leaves, an acidic solution of 1.3 to 13 mM monovalent acid can be used. When the 1.3 to 13 mM monovalent acidic solution is acetic acid, it corresponds to 0.008 to 0.08 wt% acetic acid.

  In addition, regarding the pH of the acidic solution, when the pH is about 2 or less, or in the case of an inorganic acid solution, the tea leaves are discolored and reddish, and thus the base (arginine, ammonia, sodium hydroxide, potassium hydroxide, etc. ) To adjust the pH. In particular, a buffer solution prepared by adding an acid having a plurality of dissociating groups and adding a base that is less than the neutralization amount is easy to control pH because of its high buffering capacity. Since there is no fluctuation, it is desirable as an acid in this case. Examples of such a buffer include a buffer obtained by adding about 1.2 equivalents (0.12 M) of sodium hydroxide to 0.1 M phosphoric acid.

  When boiling green tea leaves in such an acidic solution, it is possible to heat the prepared acidic solution and add the raw leaves to it, but the volatile substances will be vaporized by heating the acidic solution. Therefore, it is possible to boil raw leaves by adding an acid, a base, a salt or the like to boiling hot water to a predetermined concentration to prepare an acidic solution.

  The amount of the acidic solution to be used is arbitrary as long as the green leaves of green tea can be immersed in the solution, and may be, for example, 1 L per 100 g of green leaves of green tea. The boiling temperature is preferably 80 ° C. or higher, and more preferably close to 100 ° C. The reason for this temperature is that caffeine dissolves easily at high temperatures, particularly at 80 ° C or higher, so caffeine has a greater solubility difference depending on temperature than catechin, and heat treatment makes the enzyme in tea leaves insoluble. This is because it needs to be activated. The boil time is, for example, 5 to 300 seconds, preferably 5 seconds to 120 seconds, and more preferably 20 to 40 seconds. However, the boil time varies depending on the amount of fresh leaves added at once, the heat amount of the heat source, and the like. The longer the boil time, the more caffeine elutes, and the more caffeine in the tea leaves tends to decrease. It is desirable.

  Tea leaves boiled in an acidic solution according to the above method are commercialized according to a normal tea production process, and unfermented tea with less caffeine is produced.

According to another aspect of the present invention, the unfermented tea with less caffeine of the present invention is prepared by a method comprising a step of steaming fresh green tea leaves and a step of washing the tea leaves obtained by the step with an acidic solution. Is done.
In this embodiment, the tea leaves are steamed according to a technique used in a general green tea manufacturing method. The steaming time is generally from 10 seconds to 300 seconds, suitably from 30 seconds to 150 seconds.

Wash steamed tea leaves with acidic solution. The above-mentioned thing can be used about an acidic solution. Washing can be performed by immersing the tea leaves in an acidic solution. Or it can also carry out by wash-washing tea leaves with an acidic solution.
The immersion of the tea leaves in the acidic solution can be performed by placing the steamed tea leaves in the acidic solution and allowing to stand at room temperature for 10 seconds to 600 seconds, for example. The acid solution may be appropriately stirred during the immersion.

  Since the caffeine removal ability varies depending on the concentration and buffer capacity of the acidic solution, it is desirable to appropriately set the type, concentration and pH of the acidic solution to be employed. Regarding the concentration of the acidic solution, the acid content is preferably equal to or more than the amount of caffeine to be removed, and more preferably from the same amount to about 100 times the acid content. The reason for setting the concentration of the acidic solution in this way is as described above. However, in the case of shower cleaning, unlike the case of cleaning by immersion, the reaction rate with caffeine tends to be low, so the acid content may be increased to about 1000 times.

  Moreover, since the immersion time of the tea leaf in the acidic solution and the steaming time of the tea leaf also affect the effect of reducing caffeine, it is desirable to set appropriately. The immersion time is, for example, 10 to 600 seconds, preferably 30 to 300 seconds, and more preferably around 60 seconds. If soaked for a long period of time, caffeine tends to elute, and caffeine in the tea leaves tends to decrease. However, since the tea leaves turn brown and catechins also elute simultaneously, it is desirable that the soaking time should not be longer than 300 seconds. Furthermore, the steaming time of the tea leaves is preferably 10 to 300 seconds, more preferably 20 to 150 seconds. The steaming time is preferably not shorter than 10 seconds because it requires time to destroy the cell wall of tea leaves and inactivate the enzyme activity in tea leaves, while caffeine elutes as much as it becomes longer. Although it becomes easy, since it will become difficult for the subsequent tea-making process if it steams for a long time, it is desirable not to become longer than 300 seconds.

  Even if the raw leaves before steaming are washed with an acidic solution as described above, caffeine does not elute and caffeine in the tea leaves does not decrease, but once steamed tea leaves are washed with an acidic solution as described above, Caffeine elutes and caffeine in tea leaves decreases. This is thought to be because caffeine in cells easily eluted due to the destruction of cells on the surface of tea leaves by heating. At the time of washing, since the difference between the solubility of caffeine in an acidic solution and the solubility of catechin in an acidic solution is effective, catechin is not eluted and caffeine is selectively eluted.

  Tea leaves washed with an acidic solution according to the above method are commercialized according to a normal tea production process, and unfermented tea with less caffeine is produced.

  In addition, tea leaves treated as described above by boiling with an acidic solution and tea leaves treated as described above by washing with an acidic solution remove the acidic solution attached to the tea leaves immediately after the treatment. It is desirable to keep it. The acidic solution can be removed by washing the tea leaves with water or neutralizing the acidic solution adhering to the tea leaves with a basic neutralizing solution or basic steam. Here, washing and neutralization may be performed by pouring running water or a neutralizing solution over tea leaves and washing the tea leaf surface, or by immersing the tea leaves in water or neutralizing solution. . Neutralization causes browning or elution of catechins when shaken to the alkali by this treatment. Therefore, a solution of a volatile salt (for example, ammonium carbonate or sodium bicarbonate) having a concentration of 1/100 to 1 of the acid used is preferably used. It is desirable. Further, a basic vapor produced by vaporizing a volatile basic compound such as ammonia or a salt thereof may be used for neutralization.

  If the acidic solution adhering to the tea leaves is not removed and left attached to the tea leaves, the chlorophyll decomposes and discoloration of the tea leaves occurs, but the tea leaves are washed with water or neutralized. As a result, discoloration can be suppressed. In particular, when cold water is used, the catechin does not dissolve from the tea leaves, and the browning of the chlorophyll due to heat can be suppressed.

  Moreover, you may perform both neutralization and water washing by wash | cleaning and neutralizing tea leaves with the basic neutralization solution, and washing with water after that. Washing with water after neutralization in this way is desirable because basic substances do not remain in the tea leaves.

[Example 1]
After boiling 10 L of water, 10 cc of acetic acid was added and 100 g of fresh tea leaves were boiled for 45 seconds. This was repeated 10 times to obtain 1 kg of boiled tea leaves. Thereafter, the water was drained, and rough kneading, twisting, curling, and scouring were performed as usual to produce low caffeine tea 1.
Further, after boiling 10 L of water, 10 cc of acetic acid was added, 100 g of fresh tea leaves were boiled for 45 seconds, and then directly washed with water, and this was repeated 10 times to obtain 1 kg of boiled tea leaves. Thereafter, the water was drained, and rough kneading, spraining, middle mushrooming, and scouring were performed as usual to produce low caffeine tea 2.

After boiling 10 L of water, 10 cc of acetic acid was added, 100 g of fresh tea leaves were boiled for 45 seconds, and then directly washed with 0.01% sodium bicarbonate water. This was repeated 10 times to obtain 1 kg of boiled tea leaves. Thereafter, the water was drained, and rough kneading, twisting, curling, and scouring were performed as usual to produce low caffeine tea 3.
Further, after boiling 10 L of water, 100 g of fresh tea leaves were repeated for 45 seconds, and this was repeated 10 times to obtain 1 kg of boiled tea leaves. After that, the water was drained and rough kneading, spraining, middle mushrooming, and scouring were performed as usual, and a control tea was made.

In this example, the pH of the aqueous solution was 3.5 by adding acetic acid.
With respect to the low caffeine tea and the control tea thus produced, the total catechin amount and caffeine amount were measured. The measurement was performed by the HPLC method. In addition, the degree of coloring of the low caffeine tea and the control tea was usually observed with the naked eye with 10 as the crude tea, and scored by the deduction method.

The results are shown in Table 1 below.

  In all of the low caffeine teas 1 to 3, although the amount of catechin was almost the same as that of the boiled water (control tea), the amount of caffeine decreased by about 40%. Moreover, discoloration was reduced by washing with water or neutralization with alkali.

[Example 2]
1 kg of fresh tea leaves were placed on a belt conveyor and steamed for 90 seconds each, and then infiltrated with 10 L of 0.1% acetic acid solution for 1 minute. The infiltration into the acetic acid solution may be performed using 1 L of 1% acetic acid solution. After that, the water was drained, and rough kneading, spraining, curling, and scouring were carried out as usual to produce low caffeine tea 4.
1 kg of fresh tea leaves were placed on a belt conveyor and steamed for 90 seconds each, and then infiltrated with 10 L of 0.1% acetic acid solution for 1 minute. Then, after washing with water, the water was drained, and rough kneading, twisting, curling, and scouring were performed as usual to produce low caffeine tea 5.

1 kg of fresh tea leaves were placed on a belt conveyor and steamed for 90 seconds each, and then infiltrated with 10 L of 0.1% acetic acid solution for 1 minute. Then, after washing with 0.01% sodium bicarbonate water, the water was drained, and rough kneading, twisting, curling, and scouring were performed as usual to produce low caffeine tea 6.
1 kg of fresh tea leaves were placed on a belt conveyor and steamed for 90 seconds each, and then infiltrated with 10 L of 1% acetic acid solution for 1 minute. Thereafter, the water was drained, and rough kneading, twisting, curling, and scouring were performed as usual to produce low caffeine tea 7.

1 kg of fresh tea leaves were placed on a belt conveyor and steamed for 90 seconds each, and then infiltrated with 10 L of 0.1% citric acid solution for 1 minute. Then, after washing with water, the water was drained and coarse koji, twisting, curling, and scouring were performed as usual to produce low caffeine tea 8.
After placing 1 kg of fresh tea leaves on a belt conveyor and steaming for 90 seconds each, rough kneading, twisting, curling, and scouring were performed as usual to make a control tea.

In this example, the pH of the aqueous solution became 2 to 4 by adding acetic acid or citric acid. Specifically, they were 0.1% acetic acid pH 3.5, 1% acetic acid pH 3.7, and 0.1% citric acid pH 2.5.
In the same manner as in Example 1, the low caffeine tea and the control tea thus prepared were measured for the total catechin amount and caffeine amount, and evaluated for the degree of discoloration.

The results are shown in Table 2 below.

  In all of the low caffeine teas 4 to 8, the amount of caffeine was reduced by about 15 to 40%, although the amount of catechin was almost the same as that of boiled water (control tea). Moreover, discoloration was reduced by washing with water or neutralization with alkali.

[Example 3]
The effect of the difference in acid concentration in the acidic solution on the caffeine reduction rate was examined.
After boiling 10 L of water, acetic acid was added in various concentrations as shown in Table 3, and 100 g of fresh tea leaves were boiled for 45 seconds. This was repeated 10 times to obtain 1 kg of boiled tea leaves. After that, the water was drained, and rough kneading, twisting, middle mushrooming, and scouring were performed as usual to make low-caffeine tea. In the same manner as in Example 1, the total catechin amount and caffeine amount were measured. The results are shown in Table 3.

  When the acetic acid concentration was low, the caffeine reduction rate was low, and as the acetic acid concentration increased, the caffeine reduction rate tended to increase. However, since an acetic acid concentration of 10% by weight causes elution of catechin, an acetic acid concentration of 1% by weight or 0.1% by weight is preferable in order to selectively remove caffeine.

Claims (10)

  Non-fermented tea with less caffeine, obtained by a method comprising a step of boiling green tea leaves in an acidic solution. Boiling green tea leaves in an acidic solution;
A non-fermented tea with less caffeine, which is obtained by a method comprising a step of washing the tea leaves obtained by the above-mentioned step with water. Boiling green tea leaves in an acidic solution;
A non-fermented tea with less caffeine, which is obtained by a method comprising a step of neutralizing tea leaves obtained by the above step with an alkaline fluid. Steaming green tea leaves,
A non-fermented tea with less caffeine, which is obtained by a method comprising a step of washing the tea leaves obtained by the above step with an acidic solution. Steaming green tea leaves,
Washing the tea leaves obtained by the above step with an acidic solution;
A non-fermented tea with less caffeine, obtained by a method comprising a step of washing the washed tea leaves with water. Steaming green tea leaves,
Washing the tea leaves obtained by the above step with an acidic solution;
A non-fermented tea with less caffeine obtained by a method comprising a step of neutralizing the washed tea leaves with an alkaline fluid.   A method for producing unfermented tea with less caffeine, comprising a step of boiling green tea leaves in an acidic solution. Boiling green tea leaves in an acidic solution;
A method for producing unfermented tea with less caffeine, comprising washing the tea leaves obtained in the above step with water or neutralizing the tea leaves obtained in the above step with an alkaline fluid. Steaming green tea leaves,
A method for producing unfermented tea with less caffeine, comprising a step of washing the tea leaves obtained by the above step with an acidic solution. Steaming green tea leaves,
Washing the tea leaves obtained by the above step with an acidic solution;
A method for producing unfermented tea with less caffeine, comprising washing the washed tea leaves with water or neutralizing the washed tea leaves with an alkaline fluid.