JP2018029566A - Method for reducing gallate-type catechins using tea leaves - Google Patents

Abstract

An object of the present invention is to provide a method for reducing gallate catechins in a green tea extract, and to provide an easy-to-drink green tea drink with reduced astringency by reducing gallate catechins.
A method for producing a green tea extract comprising a step of bringing a raw material green tea extract into contact with a tea shell.
[Selection figure] None

Description

The present invention relates to a method for producing a green tea extract with reduced gallate-type catechins. The present invention also relates to a packaged green tea beverage containing a green tea extract with reduced gallate catechins. The present invention further relates to a method for reducing gallate catechins in a green tea extract and a method for reducing astringency of a green tea extract.

A green tea beverage obtained by extracting green tea with an aqueous solvent contains useful components such as non-polymer catechins, caffeine, amino acids, and vitamin C. Among these, non-polymer catechins are attracting attention for various health functions such as antioxidant and antibacterial effects. On the other hand, non-polymer catechins are components that exhibit astringency and astringency, and if they are too strong, they are accompanied by discomfort or aversion. Among non-polymer catechins, gallate-type catechins (epigallocatechin gallate, gallocatechin gallate, epicatechin gallate and catechin gallate) are particularly problematic in that they have a strong astringency remaining in the back mouth. It is desirable to keep astringency and astringency within a certain level.

A number of methods for alleviating such unpleasant astringency and astringency have been proposed so far. For example, a method of adding collagen (Patent Document 1), a method of adding casein (Patent Document 2), a method of adding protamine and / or its salt (Patent Document 3), a method of adding a certain amount of sugar alcohols (Patent Document 3) Documents 4 and 5), a method of adding xyloglucan (Patent Document 6), a method of adding cyclodextrin (Patent Documents 7 and 8), a method of containing an extract derived from sweet potato (Patent Document 9), and adding sucralose (Patent Document 10), a method of adding one or more of enzyme-treated isoquercitrin, enzyme-treated rutin and methyl hesperidin (Patent Document 11), a method using deNaCl-treated seawater (Patent Document 12) , Tannase treatment method (Patent Document 13), activated carbon method (Patent Document 14), polyvinylpyrrolidone added to A method of tea beverage reduce fungi (Patent Document 15) have been proposed.

JP, 2014-18103, A JP 2005-124540 A JP-A-6-153875 Japanese Patent Laid-Open No. 7-274829 JP-A-11-253102 Japanese Patent Laying-Open No. 2005-245291 Japanese Patent Laid-Open No. 10-4919 JP-A-2005-73534 JP 2002-34471 A Japanese Patent No. 3938968 JP 2013-110989 A JP 2004-113253 A JP 2012-183079 A International Publication No. 2011/0774538 JP-A-9-220053

In the methods described in Patent Documents 1 to 12, food additives such as collagen are used to reduce astringency. However, the method of using food additives other than green tea in such green tea presents a flavor derived from food additives and the like at the same time as reducing the astringency, and impairs the original flavor of green tea. In addition, it is necessary to clearly indicate that food additives are used in the raw material labeling, which is not suitable for the health image of green tea. Patent Documents 1 to 12 do not discuss reducing gallate catechins in a green tea extract.
The tannase treatment described in Patent Document 13 has the disadvantage that the gallic acid content increases and the sourness becomes stronger. The activated carbon treatment described in Patent Document 14 has a drawback in that various components other than the astringent components are adsorbed and the flavor as green tea is impaired. Since the method described in Patent Document 15 uses polyvinyl pyrrolidone (PVPP), which is a synthetic resin, there is room for improvement to reduce the astringency of the green tea extract more safely.

An object of this invention is to provide the method of reducing the gallate type catechin in green tea extract. Another object of the present invention is to provide an easy-to-drink green tea beverage with reduced astringency by reducing gallate catechins.

The present inventors paid attention to the point that it is difficult to feel astringency in green tea. Analysis of matcha catechins revealed that 70% of non-gallate catechins are distributed in tea extract and 30% in tea leaves, while 30% of gallate catechins are distributed in tea leaves. It was found that 70% of the tea extract was distributed in the tea leaves. Based on this finding, the possibility of gallate-type catechins being adsorbed on the tea husk by returning the tea husk after extraction to the tea brewing solution was intensively studied. Surprisingly, the tea husk was brought into contact with the green tea extract. As a result, it was found that gallate catechins in the green tea extract are surely reduced, and the present invention has been completed. It has been common knowledge that green tea components are extracted from tea leaves, and the phenomenon that tea shells adsorb green tea components cannot be predicted at all.

Although this invention is not limited to the following, the following invention is included.
The method for producing a green tea extract of the present invention includes a step of bringing a raw material green tea extract into contact with a tea shell.
By bringing the raw material green tea extract into contact with the tea husk, gallate catechins in the green tea extract are reduced as compared to before bringing the tea husk into contact. For this reason, a green tea extract with reduced astringency can be obtained. The reason why gallate-type catechins are reduced is presumed to be because gallate-type catechins are adsorbed to tea leaves as described above. According to the production method of the present invention, it is possible to reduce the astringency of the green tea extract by a simple operation using tea leaves that are highly safe to the human body and the environment. Moreover, this invention also has the advantage that the tea-husk which is waste can be used effectively.

In the present invention, as will be described later, non-gallate catechins in the green tea extract can be reduced by selecting the tea husk to be used, but also when non-gallate catechins are reduced, Galate type catechins can be further reduced.
The method for producing a green tea extract of the present invention can be said to be a method for producing a green tea extract with reduced gallate catechins. The green tea extract obtained by the present invention can also be referred to as a tea-shell-treated green tea extract. Note that caffeine in the green tea extract is not significantly reduced even when the raw green tea extract is brought into contact with the tea husk.

In the production method of the present invention, the tea husk is preferably tea husk having an extraction rate of 20% or more. Moreover, it is preferable that the tannin content of a tea-shell is 1 to 10 weight% in dry weight.
As the tea husk in the present invention, the above-mentioned tea husk is preferable. When such a tea shell is used, gallate catechins in the green tea extract are further reduced, and the astringency of the green tea extract can be further reduced.

In the manufacturing method of this invention, it is preferable that the temperature of the raw material green tea extract made to contact with a tea shell is 0-50 degreeC. It is preferable that the temperature of the raw green tea extract is 0 to 50 ° C. because gallate catechins in the green tea extract can be further reduced.

In the production method of the present invention, the dry weight of tea husk (A) in the step of bringing the raw material green tea extract into contact with tea husk and the total weight of gallate catechins and non-gallate catechins in the raw green tea extract (B ) Ratio (A) / (B) is preferably 1 to 100.
When the ratio (A) / (B) is within the above range, the gallate catechins in the green tea extract can be more sufficiently reduced by the tea husk.

In the manufacturing method of this invention, it is preferable that the time of the process which makes a raw material green tea extract and a tea shell contact is 1-180 minutes. When the green tea extract and tea husk are brought into contact with each other for the above time, gallate catechins in the green tea extract can be further reduced.
The tea leaves used in the production method of the present invention are preferably green tea leaves. When green tea husk is used, astringency can be reduced without impairing the original flavor of green tea. For this reason, the flavor of the green tea extract obtained becomes favorable.
The production method of the present invention preferably includes a step of removing tea leaves from the green tea extract.

The container-packed green tea beverage of the present invention includes a green tea extract produced by the production method of the present invention.
The green tea extract produced by the production method of the present invention has less astringency and is easy to drink because gallate catechins are reduced.

The method for reducing gallate-type catechins in the green tea extract of the present invention is characterized by including a step of bringing tea shells into contact with the raw green tea extract. The method for reducing astringency of a green tea extract of the present invention includes a step of bringing a green tea extract into contact with a tea husk.
According to the method of the present invention, the amount of gallate-type catechins in the green tea extract can be reduced by a simple operation using tea leaves that are highly safe for the human body and the environment. Moreover, the astringency of the green tea extract can be reduced.

According to the present invention, a green tea extract with reduced gallate catechins and reduced astringency can be produced. In addition, the gallate catechins of the green tea extract can be safely reduced by a simple operation. The green tea extract obtained by the production method of the present invention has a reduced astringency and is useful as a raw material for easy-to-drink green tea beverages. ADVANTAGE OF THE INVENTION According to this invention, the gallate type | mold catechin can be reduced, The astringency is reduced and the container-packed green tea drink which is easy to drink can be provided.

FIG. 1 is a graph showing the rate of change (%) of each component in a green tea extract by addition of tea leaves or tea leaves. FIG. 2 is a graph showing the rate of change (%) of each component in the green tea extract with respect to the added amount (% by weight) of tea husk. FIG. 3 is a graph showing the results of sensory evaluation of the green tea extract with respect to the added amount (% by weight) of tea husk. FIG. 4 is a graph showing the change rate (%) of each component in the green tea extract with respect to the addition time of the tea husk. FIG. 5 is a graph showing the change rate (%) of each component in the green tea extract by addition of tea husk or polyvinylpolypyrrolidone (PVPP).

In the present specification, gallate-type catechins are (−)-epigallocatechin gallate, (−)-gallocatechin gallate, (−)-epicatechin gallate and (−)-catechin gallate. Is a general term. When referring to the content of gallate catechins, it refers to the total amount of the above four types.
Non-gallate catechins are a general term for four types of non-gallate catechins, (−)-epigallocatechin, (−)-gallocatechin, (−)-epicatechin and (+)-catechin. When referring to the content of non-gallate catechins, it refers to the total of the above four types.
Furthermore, catechins is a general term for eight types of gallate catechins and non-gallate catechins. The content of catechins is the total amount of eight kinds of gallate catechins and non-gallate catechins.
The content of gallate catechins and non-gallate catechins is measured by the method described in Examples using high performance liquid chromatography (HPLC).

<Method for producing green tea extract>
The method for producing a green tea extract of the present invention includes a step of bringing a raw material green tea extract into contact with a tea shell.
In the production method of the present invention, the gallate catechins in the green tea extract are reduced by bringing the raw green tea extract into contact with the tea husk. For this reason, a green tea extract with reduced astringency can be obtained by a simple operation. Moreover, since the tea husk is highly safe with respect to a human body and an environment, it is used suitably for manufacture of food-drinks. As will be described later, polyvinylpyrrolidone also adsorbs gallate-type catechins, but the use of tea husk is preferable because it is superior in safety to the use of synthetic resin. Furthermore, the use of tea husk as waste is preferable because it leads to effective utilization of resources.

The production method of the present invention may have a step other than the step of bringing the raw material green tea extract into contact with the tea shell. For example, you may have 1 or 2 or more processes, such as the process of preparing the raw material green tea extract made to contact with tea leaves, the process of preparing tea leaves, and the process of removing tea leaves from the green tea extract made contact with tea leaves. .

(Raw green tea extract)
In the present invention, the raw material green tea extract refers to a green tea extract that is brought into contact with a tea shell.
The raw green tea extract used in the present invention includes an extract of green tea leaves. For example, a green tea extract obtained by extracting green tea leaves with an aqueous solvent can be used as a raw green tea extract as it is. Examples of the aqueous solvent used for extraction include water, an aqueous alcohol solution (for example, an aqueous ethanol solution), and preferably water. The temperature at the time of extraction is not particularly limited, and may be set as appropriate. Moreover, the concentrate which concentrated the green tea extract can also be used as a raw material green tea extract. The concentrate of the green tea extract is obtained by removing a part of the solvent from the green tea extract and increasing the concentration of catechins and the like. Instead of extracting from tea leaves, a concentrate or dried product of green tea extract may be dissolved or diluted in water and used as a raw green tea extract. Furthermore, you may use together the extract from a tea leaf, the concentrate of a green tea extract, or a dried material. As a form of raw material green tea extract, a liquid or slurry form is preferable, More preferably, it is a liquid.

As an example of the raw material green tea extract, an example of a method for preparing a green tea extract is described below.
As tea leaves of green tea, tea leaves such as camellia (scientific name: Camellia sinensis) are used as raw materials, and tea, such as crude tea and finished tea, produced by a process of drying quickly after enzyme inactivation after harvesting, was made. Tea leaves are preferably used. As tea leaves of green tea, more preferably finished tea is used. The tea leaves that can be used in the present invention are not particularly limited as long as they are green tea, their varieties, production areas, cultivation methods, tea seasons, and the like.

Examples of varieties of tea tree include Yabukita, Yutaka Midori, Okumidori, Sayaka Kaori, Kanaya Midori, Samidori and Asatsuyu. Examples of production areas include Kyoto, Nara, Shiga, Shizuoka, Kagoshima, Mie, Kumamoto, Fukuoka, Miyazaki, Saitama, and the like. Cultivation methods include open ground, cover, gyokuro and the like. Examples of the tea period include Ichiban-cha, Niban-cha, Sanban-cha, Yonban-cha, Winter / Spring / Autumn-cha, and Karan-ban. Any of these may be used for the green tea leaves used in the present invention. Further, one type of tea leaf may be used, or two or more types may be used in combination. The harvesting (plucking) of fresh leaves may be carried out in a normal manner, and the plucking method is not limited to such methods as hand picking, picking, and mechanical picking, and any method may be used.

Raw tea is obtained by processing raw leaves. The processing method for obtaining crude tea is not particularly limited. The process of rough tea processing of ordinary sencha generally includes processes such as steaming, rough koji, cocoon twisting, middle koji, koji and drying. In the present invention, in addition to ordinary sencha, any rough tea processing method performed in deep steamed tea, kettle roasted tea, tamago green tea, hand-made tea, kabuse tea, gyokuro, strawberry tea and the like may be used. It is also possible to omit the koji from the manufacturing method of ordinary sencha and dry it after the middle koji. Moreover, you may process into tea. That is, after steaming fresh leaves, the tea leaves can be obtained through a tea ceremony machine, a tea ceremony furnace, and a dryer. And matcha can be manufactured from rough tea.

Finished tea can be obtained by processing crude tea. The finishing process for obtaining finished tea from crude tea generally consists of sieving of crude tea, cutting of large tea, separation of powder and tree stalks, firing, combination, etc. The processing method is not particularly limited.
The tea leaves of green tea may be any of sencha, deep-steamed tea, kettle roasted tea, tamago green tea, hand-made tea, kabuse tea, gyokuro, and strawberry tea. Sencha and strawberry tea are preferred.

The extraction method and extraction conditions for extracting green tea leaves with an aqueous solvent are not particularly limited, and known methods and conditions can be employed. For example, the extraction temperature is preferably 5 to 95 ° C. For example, the aqueous solvent is preferably used 5 to 200 times by weight with respect to green tea leaves. In the preparation of the green tea extract, it is preferable to perform a step of removing the tea leaves that are the extraction residue from the green tea extract obtained by extraction. As a raw material green tea extract such as a green tea extract used in the present invention, a green tea extract from which tea leaves have been removed is preferable. The method for removing the tea leaves is not particularly limited, and examples thereof include filtration.
The green tea extract thus obtained can be used as a raw material green tea extract in the present invention as it is or after being concentrated. If desired, cooling the green tea extract, removing fine solids from the green tea extract (eg, filtration, centrifugation, etc.), water, green tea extract, antioxidant, pH adjuster, etc. You may perform 1 or 2 or more processes, such as the process of adding green tea, the process of concentrating a green tea extract, the process of disinfecting a green tea extract. However, these steps are merely examples, and the present invention is not limited to them. For example, the order of the steps is not particularly limited. Moreover, you may perform another process.

The pH of the raw green tea extract is preferably 5-7. Moreover, as for Brix of a raw material green tea extract, 0.05-2% is preferable. Brix can be measured with a densitometer (for example, a digital suggestion densitometer, model DD-7, manufactured by ATAGO). For Brix, the value measured at 20 ° C. is used.

(Tea husk)
The tea husks used in the present invention are made from the leaves and stems of tea leaves or those obtained by processing them as raw materials (tea husk raw materials), and the solid content (extraction residue) after this tea husk raw material is extracted with an aqueous solvent. means. An extraction residue (tea leaf extraction residue) obtained by extracting tea leaves with an aqueous solvent is preferable. Examples of the tea shell material include tea leaves of green tea, hoji tea, oolong tea; stem tea, and one or more kinds can be used, and tea leaves of green tea are preferable. The tea leaves of green tea are not particularly limited, and the green tea leaves described above can be used, and tea leaves of sencha and mocha tea are preferred. The tea shell of the present invention is preferably a green tea tea shell made from green tea leaves. When the green tea husk is used, the astringency of the green tea extract can be reduced without impairing the original flavor of green tea.
The form of the tea husk raw material is not particularly limited, and it may be a leaf, a tea pack or powder.

The number of extractions of the tea husk raw material for obtaining the tea husk is not particularly limited, and the extraction with an aqueous solvent may be performed at least once, and the extraction may be performed a plurality of times. As an aqueous solvent, the aqueous solvent mentioned above is mentioned, Water is preferable. The extraction method is not particularly limited, and a known method can be used. For example, a tea husk raw material (for example, tea leaves of green tea) and an aqueous solvent are put in a container and extracted, and then the tea husk and the extract are separated by a method such as filtration and centrifugation, and the tea husk is recovered.

As temperature of the aqueous solvent in the case of extraction for obtaining a tea husk, for example, 5 to 95 ° C is preferable, and 50 to 90 ° C is more preferable. The extraction time is preferably 1.5 to 60 minutes, and more preferably 2 to 30 minutes. When extraction is performed a plurality of times, it is preferable that the total extraction time falls within the above range. The amount of the aqueous solvent used for extraction of the tea husk raw material is preferably 5 to 200 times that of tea leaves by weight, and more preferably 20 to 150 times. When extracting several times, it is preferable that the amount of the aqueous solvent used for the extraction is within the above range.
After extraction, the tea leaves recovered from the tea extract can be used as they are in the production method of the present invention. If desired, the tea husk can be dried before use. When drying the tea husk, the drying condition of the tea husk is not particularly limited, but it is preferably dried at 40 to 100 ° C. after pressing. The drying time is preferably 60 to 300 minutes.
The water content of the tea shell is preferably 3 to 6% by weight, for example. The amount of moisture is measured by an infrared moisture meter. The shape of the tea husk is not particularly limited, and may be used after pulverization if desired.

As the tea leaves in the present invention, tea leaves having an extraction rate of 20% or more are preferable. When the tea husk having an extraction rate of 20% or more is used, gallate catechins in the green tea extract are further reduced, and the astringency of the green tea extract can be further reduced.
The extraction rate in the present invention is the weight of the extracted tea husk raw material (the tea husk raw material used for the preparation of the tea husk), the weight of the tea extract obtained by extracting the tea husk raw material, and the Brix of the tea extract. From this, the value is calculated by the following method.
Extraction rate (%) = (weight of tea extract (g)) × (Brix (%) of tea extract) / (weight of extracted tea shell raw material (g))
Brix of the tea extract can be measured with a densitometer. For Brix, the value measured at 20 ° C. is used.
The extraction rate of the tea husk obtained by extracting the tea husk raw material a plurality of times is calculated as the extraction rate for each extraction and is obtained as the sum of the extraction rates.

The extraction ratio of tea husks is more preferably 25% or more, more preferably 30% or more, and particularly preferably 35% or more, since the reduction effect of gallate catechins becomes higher. Moreover, from the viewpoint of selectivity for adsorption of gallate catechins, the tea leaves in the present invention preferably have an extraction rate of 50% or less, more preferably 45% or less.

For example, when gallate type catechins in the green tea extract are further reduced, a tea husk with an extraction rate of 30 to 50% is preferable, and a tea husk with an extraction rate of 32 to 45% is more preferable. Moreover, when reducing gallate-type catechins and non-gallate-type catechins, for example, a tea husk with an extraction rate exceeding 37% and 45% or less is preferable, and a tea husk with an extraction rate of 38 to 45% is more preferable.
When the gallate catechins in the green tea extract are selectively reduced, a tea husk with an extraction rate of 20 to 37% is preferable, a tea husk with an extraction rate of 30 to 36% is more preferable, and the extraction rate is 31 to 36%. Is more preferable.

Further, for example, the tea husk having an extraction rate of 20% or more and less than 30% (extraction rate is more preferably 21 to 29%, and further preferably 22 to 28%) reduces gallate catechins in the green tea extract, And since non-gallate type catechins can be increased, it is preferable. When such a tea husk is used, the refreshing flavor by the non-gallate catechins can be improved while reducing the astringency of the green tea extract.

As the tea husk in the present invention, a tea husk whose tannin content is 1 to 10% by weight in the dry weight is preferable. In the present invention, the tannin content of the tea husk is usually measured by the method described in the examples (iron tartrate colorimetric determination method). If the tannin content cannot be measured by the iron tartrate colorimetric method, it may be measured by the foreign dennis method. The dry weight of the tea husk is determined by measuring the water content of the tea husk and subtracting the water content from the weight of the tea husk. The amount of moisture is measured by an infrared moisture meter. When a tea husk having a tannin content of 1 to 10% by weight in the dry weight is used, gallate catechins in the green tea extract are further reduced, and the astringency of the green tea extract can be further reduced.

The tannin content of the tea husk is more preferably 2 to 7% by weight in the dry weight when, for example, gallate catechins in the green tea extract are further reduced. In the case of reducing gallate catechins and non-gallate catechins, the tannin content of the tea husk is preferably 2% by weight or more and less than 4% by weight in the dry weight, for example, 2.5 to 3.9% by weight. Is more preferable.
For example, when the gallate catechins in the green tea extract are selectively reduced, the tannin content of the tea husk is preferably 4 to 10% by weight, more preferably 4 to 7% by weight in the dry weight. 6% by weight is more preferred.

Further, the tea husk having a tannin content exceeding 7% by weight and not more than 10% by weight (more preferably 7.2 to 9.5% by weight) in the dry weight reduces gallate catechins in the green tea extract, And since non-gallate type catechins can be increased, it is preferable. When such a tea husk is used, the refreshing flavor by the non-gallate catechins can be improved while reducing the astringency of the green tea extract.

The tea husk in the present invention preferably has a weight ratio of gallate catechins content to non-gallate catechins content (hereinafter also referred to as gallate / non-gallate weight ratio) of 1.6 or more. When the gallate / non-gallate weight ratio of the tea husk is 1.6 or more, gallate catechins in the green tea extract are further reduced, and the astringency of the green tea extract can be further reduced. The weight ratio of the gallate type / non-gallate type of the tea husk is more preferably 1.65-15. The content of gallate catechins and the content of non-gallate catechins in the tea husk are measured by the method described in the examples.

For example, when gallate type catechins in the green tea extract are further reduced, the weight ratio of the gallate type / non-gallate type of the tea husk is preferably 3-15, more preferably 3.2-14. For example, when the gallate catechins in the green tea extract are selectively reduced, the gallate / non-gallate weight ratio of the tea husk is preferably 1.65 to 5, and more preferably 3 to 5.
For example, when reducing gallate type catechins in green tea extract and increasing non-gallate type catechins, the weight ratio of gallate type / non-gallate type of tea husk is preferably 1.65-3, 1.65 -2.5 is more preferable.

The catechin content of the tea husk (the total content of gallate catechins and non-gallate catechins) is preferably 10% by weight or less, more preferably 2 to 10% by weight in the dry weight. If the tea catechin content in the above range is used, gallate-type catechins can be further reduced and the astringency of the green tea extract can be further reduced.

(Process of bringing tea leaves into contact with raw green tea extract)
The method of bringing the raw green tea extract into contact with the tea husk is not particularly limited. For example, the method of immersing the tea husk in the raw green tea extract in a container, the method of filling the tea husk into a column or the like and passing the raw green tea extract through Is mentioned. Especially, the method of immersing a tea-shell in the raw material green tea extract in a container is preferable. The step of bringing the raw material green tea extract into contact with the tea husk may be performed once, but may be performed twice or more.

As for the temperature of the raw material green tea extract made to contact with a tea shell, 0-50 degreeC is preferable. It is preferable that the raw green tea extract at a temperature of 0 to 50 ° C. is brought into contact with the tea shell because gallate catechins can be adsorbed more efficiently and gallate catechins in the green tea extract can be reduced. The temperature of the raw green tea extract to be brought into contact with the tea husk is more preferably 0 to 40 ° C.

The time for the step of bringing the raw material green tea extract into contact with the tea shell is preferably 1 to 180 minutes. When the raw green tea extract and the tea husk are brought into contact with each other for 1 to 180 minutes, gallate catechins in the green tea extract can be reduced. From the viewpoint of stable production, microbial risk, and generation of a delicious taste, the time for the step of bringing the raw material green tea extract into contact with the tea shell is more preferably 3 to 150 minutes, and further preferably 5 to 150 minutes. When the raw green tea extract and tea husk are contacted for the above time, the concentration ratio of gallate catechins / non-gallate catechins in the green tea extract can be reduced.

Ratio of dry weight of tea husk (A) and total weight (B) of gallate catechins and non-gallate catechins in raw green tea extract (A) / (B) is preferably 1 to 100. When the ratio of (A) / (B) is within the above range, gallate catechins in the green tea extract can be further reduced. The ratio of (A) / (B) may be in the above range at the start of bringing the raw material green tea extract into contact with the tea shells. The ratio of (A) / (B) is more preferably 1 to 75, and further preferably 2 to 50.

It is preferable to remove the tea husk from the green tea extract after contacting the raw green tea extract and the tea husk for a predetermined time. The production method of the present invention preferably includes a step of removing tea leaves from the green tea extract. The method for removing the tea husk is not particularly limited, and a known method such as filtration or centrifugation can be employed.

In the green tea extract produced by the production method of the present invention, gallate catechins are reduced and astringency is reduced as compared with that before contact with the tea husk (raw green tea extract).
If desired, the resulting green tea extract may contain an antioxidant such as L-ascorbic acid or a salt thereof, and a pH adjuster such as sodium bicarbonate. Moreover, it can also concentrate by removing a part of solvent from a green tea extract. The concentration method is not particularly limited, and examples thereof include normal pressure concentration, reduced pressure concentration, and membrane concentration. A green tea beverage can be obtained by diluting the green tea extract or the concentrate obtained by concentrating the extract with water or the like. Further, the green tea extract can be dried and used as a dried product (powder).

The green tea extract or concentrate or dried product obtained by the production method of the present invention is suitable as a raw material for green tea beverages, but is also suitable as a raw material for foods and beverages other than green tea beverages (for example, alcoholic beverages and processed foods). Can be used for
The green tea extract obtained by the production method of the present invention is also included in the present invention.

(Green tea drink)
A green tea beverage containing the green tea extract produced by the production method of the present invention (hereinafter also referred to as the green tea beverage of the present invention) is also encompassed by the present invention. The form of the green tea beverage of the present invention is not particularly limited, but is preferably a green tea beverage packed in a container.
The container-packed green tea beverage containing the green tea extract produced by the production method of the present invention is also one aspect of the present invention.

The method for producing the green tea beverage is not particularly limited, and the green tea extract produced by the production method of the present invention can be used as it is or diluted with water or the like to make a green tea beverage. Moreover, the green tea drink obtained by the manufacturing method of this invention and another green tea extract can also be mixed, and a green tea drink can also be manufactured. Furthermore, the green tea beverage of the present invention can also be obtained by diluting the concentrate or dried product of the green tea extract obtained by the production method of the present invention with water or the like. In addition, when a green tea extract contains the tea shell used for the manufacture, it is preferable to remove the tea shell from the green tea beverage.
The green tea beverage of the present invention contains a green tea extract obtained by the above production method, so that it is easy to drink with little astringency.

When obtaining a green tea beverage containing the green tea extract obtained by the production method of the present invention, for example, a cooling step for cooling the green tea extract, a filtration step for removing fine solids from the extract, Add water, green tea extract, antioxidant (for example, L-ascorbic acid or its salt), pH adjuster (for example, sodium bicarbonate), etc. to prepare green tea beverage preparation, sterilize green tea beverage preparation You may perform 1 or 2 or more processes, such as a sterilization process. However, these steps are merely examples, and the present invention is not limited to this. For example, the order of the steps can be changed, or another step can be added.

It is preferable to add an antioxidant to the green tea beverage. Moreover, it is also preferable to mix | blend a pH adjuster (for example, sodium hydrogencarbonate). Although the compounding quantity of the antioxidant in a green tea drink is not specifically limited, For example, when using L-ascorbic acid or its salt, 0.01-0.08 weight% is preferable as L-ascorbic acid, More preferably Is 0.02 to 0.06% by weight. The blending amount of the pH adjuster is preferably adjusted so that the pH of the green tea beverage is about 5-7.
The Brix of the green tea beverage is preferably 0.05-2%.

A container-packed green tea beverage can be produced by a conventional method using a green tea beverage. When it is set as a container-packed green tea beverage, it is preferable to sterilize the green tea beverage before or after filling the container, because long-term storage becomes possible. The method and conditions for sterilization may be appropriately selected from methods and conditions usually used for sterilization of green tea beverages.

The container for filling the green tea beverage is not particularly limited, and any commonly used container such as a metal container, a resin container, a paper container, or a glass container can be used. Specific examples include metal containers such as aluminum cans and steel cans; resin containers such as PET bottles; paper containers such as paper packs; glass containers such as glass bottles and the like.

(Method for reducing gallate-type catechins and method for reducing astringency of green tea extract)
The present invention also includes a method for reducing gallate-type catechins in a green tea extract, which includes a step of bringing a raw material green tea extract into contact with a tea shell. The present invention also includes a method for reducing the astringent taste of a green tea extract, which comprises a step of bringing the raw material green tea extract into contact with a tea shell.
The step of bringing the raw material green tea extract into contact with the tea husk and the preferred embodiment thereof are the same as the method for producing the green tea extract described above. The raw material green tea extract and tea husk are the same as described above. The method for reducing gallate-type catechins in the green tea extract of the present invention and the method for reducing the astringency of the green tea extract include a step of preparing a raw green tea extract, a step of preparing a tea husk, and removing the tea husk from the green tea extract You may have 1 or 2 or more processes, such as a process.

EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

<Measurement method of Brix of green tea extract>
For the measurement of Brix, a digital differential densitometer (model DD-7, manufactured by ATAGO) was used. The value measured at 20 ° C. was used for Brix.

<Method for measuring moisture content>
An infrared moisture meter (model FD-800, manufactured by kett) was used to measure the moisture content of tea leaves and tea leaves.

<Analytical methods for catechins, caffeine and tannins>
The analysis of catechins and caffeine contained in tea leaves, tea leaves, and green tea extracts was performed by the following method by HPLC (High Performance Liquid Chromatograph) method. Galate type catechins, non-gallate type catechins and caffeine were measured by a calibration curve method.

1. 1. Preparation of Analytical Sample 1.1 The gallate-type catechins, non-gallate-type catechins and caffeine contained in the tea husk and tea leaves and the tea leaves were extracted from 10 g of dry sample with 100 g of ethanol and used as analytical samples. As for tannin, 50-60 mL of hot water was added to a dry sample of 10 g, and heated and extracted in a constant temperature water bath at 80 ° C. or higher for 30 minutes, the volume was adjusted to 100 mL, and used as a sample for analysis.
In addition, a dry sample is the dry tea leaf and dry tea shell which were prepared in the preparation example mentioned later.
1.2 Green tea extract The green tea extract was used as is without dilution.

2. For HPLC measurement analysis of gallate catechins, non-gallate catechins and caffeine, a high performance liquid chromatograph analyzer (system controller (CBM-20A), PDA detector (SPD-M20Avp), pump (LC-30AD) ), Degasser (DGU-20A5R), column oven (CTO-20AC), autosampler (SIL-30AC), all manufactured by Shimadzu Corporation.

-Column: TSK-gel ODS-80Ts QA (4.6 mm I.D. x 150 nm), manufactured by Tosoh Corporation-Column temperature: 40 ° C
・ Mobile phase:
A liquid: 0.1% formic acid aqueous solution B liquid: 0.1% formic acid acetonitrile solution / gradient conditions (volume%)
0min B liquid 5%, 19min B liquid 20%, 20min B liquid 63%, 25min B liquid 63%, 26min B liquid 5%, 36min B liquid 5%
・ Flow rate: 1.0 mL / min
Sample injection volume: 10 μL
・ Measurement wavelength: 280 nm
Standard substances: (−)-epigallocatechin gallate, (−)-gallocatechin gallate, (−)-epicatechin gallate, (−)-catechin gallate, (−)-epigallocatechin, (−)-gallocatechin, (−)-Epicatechin and (+)-catechin, caffeine (all manufactured by Nacalai Tesque)
The amount of gallate catechins was defined as the sum of (−)-epigallocatechin gallate, (−)-gallocatechin gallate, (−)-epicatechin gallate and (−)-catechin gallate.
The amount of non-gallate catechins was defined as the sum of (−)-epigallocatechin, (−)-gallocatechin, (−)-epicatechin and (+)-catechin.

3. Analyzing method of tannin For the analysis of tannin, the method described in Anan et al. Tea Industry Research Report 71 (1990) 43-74 (iron tartrate colorimetric method) was used.
The spectrophotometer used was UV-1700 (manufactured by Shimadzu Corporation).
(1) Reagent Iron Tartrate Reagent: 100 mg of ferrous sulfate (pentahydrate) and 500 mg of potassium / sodium tartrate were dissolved in water to make 100 mL.
Buffer: Selenzen buffer at pH 7.5: 0.066M disodium hydrogen phosphate solution and 0.066M potassium dihydrogen phosphate solution were mixed to adjust to pH 7.5.
Standard solution: An aqueous solution containing 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg of ethyl gallate in 100 mL was prepared.
(2) 5 mL of a sample for operation analysis and 5 mL of iron tartrate reagent were placed in a 25 mL volumetric flask, and the volume was adjusted to 25 mL with Seirsen's phosphate buffer solution, and mixed well to develop color. The color solution was measured for absorbance at a wavelength of 540 nm with respect to a control solution (treated in the same manner by replacing the analysis sample with water).
(3) Using the method of calculation (2), 5 mL of each standard solution was taken, and the color was developed and the absorbance was determined to create a calibration curve (a calibration curve was created each time). Based on this calibration curve, the amount of ethyl gallate (Gmg / 100 mL) was first determined from the measured absorbance of the sample, and the tannin content (% by weight) was determined by the following formula.
Tannin (wt%) = G × 1.5 × 100 / W
W: Weight of dry sample in 100 mL (mg)

<Comparative Preparation Example 1>
Dry tea leaves were prepared. To 50 g of Sencha tea leaves (manufactured by Nippon Tea Sales Co., Ltd.), 1500 g of ion-exchanged water at 90 ° C. was added and extracted by stirring for 1 minute with a glass rod, and then the tea leaves were taken out from the extract. The taken tea leaves were dried at 70 ° C. for 180 minutes to obtain dry tea leaves. This dried tea leaf was designated as tea leaf 1.

By the methods of Preparation Examples 1 to 5, tea leaves used for the test were prepared.
<Preparation Example 1>
To 50 g of Sencha tea leaves (manufactured by Nippon Tea Sales Co., Ltd.), 1500 g of ion-exchanged water at 90 ° C. was added and stirred for 2 minutes to extract with a glass rod. The extracted tea husk was dried at 70 ° C. for 180 minutes to obtain a dried tea husk. This tea husk was designated as tea husk 1.

<Preparation Example 2>
In Preparation Example 1, a dry tea shell was obtained in the same manner except that the stirring time was 5 minutes. This dried tea husk was designated as tea husk 2.

<Preparation Example 3>
To 50 g of Sencha tea leaves (manufactured by Nippon Tea Sales Co., Ltd.), 90 g of ion-exchanged water at 90 ° C. was added and extracted by stirring for 5 minutes with a glass rod. To the extracted tea husk, 1500 g of ion-exchanged water at 90 ° C. was added again, and the same operation was performed (extraction twice in total). The extracted tea husk was dried at 70 ° C. for 180 minutes to obtain a dried tea husk. This dried tea husk was designated as tea husk 3.

<Preparation Example 4>
To 50 g of Sencha tea leaves (manufactured by Nippon Tea Sales Co., Ltd.), 1500 g of ion-exchanged water at 90 ° C. was added, extracted with stirring for 5 minutes with a glass rod, and then the tea husk was taken out. To the extracted tea husk, 1500 g of ion-exchanged water at 90 ° C. was added again, and the same operation was repeated twice to extract a total of three times. The extracted tea husk was dried at 70 ° C. for 180 minutes to obtain a dried tea husk. This dried tea husk was designated as tea husk 4.

<Preparation Example 5>
To 50 g of Sencha tea leaves (manufactured by Nippon Tea Sales Co., Ltd.), 1500 g of ion-exchanged water at 90 ° C. was added, stirred for 5 minutes with a glass rod and extracted, and then the tea husk was taken out from the extract. To the extracted tea husk, 1500 g of ion-exchanged water at 90 ° C. was added again, and the same operation was repeated 4 times, and extraction was performed 5 times in total. The extracted tea husk was dried at 70 ° C. for 180 minutes to obtain a dried tea husk. This dried tea husk was designated as tea husk 5.

The recovered amount (g) and water content of tea leaves 1 and tea shells 1 to 5 prepared in Comparative Preparation Example 1 and Preparation Examples 1 to 5 were measured. Further, gallate catechins, non-gallate catechins, caffeine and tannin contents were measured by the above method. The results are shown in Table 1. In Table 1, the original tea leaves are sencha tea leaves used for the preparation of tea husks. The amount of each component (gallate-type catechins, non-gallate-type catechins, caffeine and tannin) was expressed as% by weight with respect to the dry weight of tea leaves or tea shells. The dry weight of the tea husk was determined by subtracting the amount of water from the amount of tea husk recovered. The dry weight of tea leaves was determined by subtracting the amount of water from the weight of tea leaves.

In Comparative Preparation Example 1 and Preparation Examples 1-5, Brix of the extract from which tea leaves or tea leaves were taken out was measured. In Preparation Examples 3 to 5 in which extraction was performed a plurality of times, Brix of each extract was measured. The results are shown in Table 2. Table 2 shows the extraction rate of tea leaves or tea leaves.
The extraction rate was calculated by the following method from the weight of the extracted tea husk raw material (sencha tea leaf), the weight of the tea extract obtained by extracting the tea husk raw material, and the Brix of the tea extract in the preparation of the tea husk.
Extraction rate (%) = (weight of tea extract (g)) × (Brix (%) of tea extract) / (weight of extracted tea shell raw material (g))

In Table 2, the original tea leaves are sencha tea leaves used for the preparation of tea husks. The tea husk 3-1 is a dry tea husk obtained by performing extraction once in the preparation of the tea husk 3. The tea husks 4-1 to 4-2 are dry tea husks obtained by performing extraction once or twice in the preparation of the tea husk 4. The tea husks 5-1 to 5-4 are dry tea husks obtained by performing extraction 1 to 4 times in the preparation of the tea husk 5.

<Preparation Example 6>
After adding 1000 g of ion-exchanged water heated to 90 ° C. to 10 g of Sencha tea leaves (manufactured by Nippon Tea Sales Co., Ltd.), the temperature was kept constant for 5 minutes, and then passed through a 500 mesh sieve, and the extract was recovered. After cooling this liquid to room temperature, 100 mL of the clarified liquid was separated and used as a test green tea extract (raw green tea extract).

<Example 1>
To the green tea extract for testing, 0.6% by weight of each of the tea leaves 1 to 5 was added, and the supernatant of the green tea extract after 30 minutes was collected, and the extract 1-1 to 1-5 (tea shell processed green tea extract) ).
Note that the temperature of the green tea extract to which the tea husk was added was maintained at 25 ° C.

<Comparative Example 1>
Comparative extract 1-1-1-2 (original tea leaf-treated green tea extract) in the same manner as in Example 1 except that tea leaves (original tea leaves) or tea leaves 1 used for the preparation of tea shells were used instead of tea leaves. And tea leaf treated green tea extract).
In each extract obtained in Example 1 and Comparative Example 1, each component (gallate catechins, non-gallate catechins and caffeine) was quantified by HPLC.

Table 3 shows the analysis results of the components of the extract liquids 1-1 to 1-5 and the comparative extract liquids 1-1 to 1-2 obtained in Example 1 and Comparative Example 1. Further, Table 3 shows the rate of change (%) of each component.

The rate of change (%) of each component is the rate of change (%) with respect to the amount of each component (A0 (ppm)) in the green tea extract (green tea extract for test) before the addition of tea leaves or tea leaves. In Examples and Comparative Examples, the rate of change (%) of each component is the amount of each component in each extract (A1 (ppm)) and the green tea extract before addition of tea husk or tea leaf (or PVPP) (for testing) From the amount of each component (A0 (ppm)) in the green tea extract).
Rate of change (%) = 100 × (A1-A0) / A0
The term “before addition” in Table 3 refers to a green tea extract (green tea extract for testing) before adding tea husk or tea leaves.
FIG. 1 is a graph showing the rate of change (%) of each component in a green tea extract by addition of tea leaves or tea leaves. Comparisons 1-1 to 1-2 in FIG. 1 are comparison extracts 1-1 to 1-2.

When the original tea leaves were added, catechins, caffeine and Birx all increased. Addition of tea leaves 1 to 5 could reduce gallate catechins in the green tea extract (extracts 1-1 to 1-5). When the tea shells 1 to 3 were added, gallate catechins in the green tea extract were selectively reduced. Moreover, for example, when the tea husk 1 or 2 was added, non-gallate catechins in the green tea extract increased. Addition of tea husk 3 could reduce gallate catechins in the green tea extract particularly selectively (extract 1-3). Tea shells 4 to 5 were highly effective in reducing gallate catechins. When any tea husk was used, the non-gallate type / gallate type change rate ratio was 0.5 or less, and the gallate type catechins were reduced more than the non-gallate type catechins. The change in the amount of caffeine due to the addition of tea husk was small compared to gallate catechins. The change in Brix of the green tea extract due to the addition of tea husk was small.

<Example 2>
0.075% by weight, 0.15% by weight, 0.3% by weight, 0.6% by weight, 1.2% by weight, 2.4% by weight or 4.% by weight of the green tea extract for the test. 8% by weight was added, and the supernatant of the green tea extract 30 minutes later was collected to obtain a tea shell-treated green tea extract. Note that the temperature of the green tea extract to which the tea husk was added was maintained at 25 ° C.
Each component (gallate-type catechins, non-gallate-type catechins and caffeine) was quantified by HPLC for each tea-shell-treated green tea extract. The results are shown in Table 4. The amount of tea husk added is 0, which is the green tea extract before the addition of the tea husk (green tea extract for testing). FIG. 2 is a graph showing the rate of change (%) of each component in the green tea extract with respect to the added amount (% by weight) of tea husk.

By the panel of three persons who were trained in sensory evaluation, for each tea-shell-treated green tea extract of Example 2, the astringency and the sense of concentration were compared with the untreated tea-shell extract (green tea extract for testing) as follows. And sensory evaluation.
7 points: 6 points felt very strong: 5 points felt strong: 4 points felt somewhat strong: 3 points comparable: 2 points felt somewhat weak: 1 point felt weak: 1 point felt very weak

FIG. 3 is a graph showing the results of sensory evaluation of the green tea extract with respect to the added amount (% by weight) of tea husk. The result of FIG. 3 is shown by the average score of evaluation by three panels.
As the amount of tea husk added increased, the astringency decreased. The degree of reduction was larger than the degree of change in the sense of concentration, and astringency was suppressed while maintaining the richness of the taste. As a result, a tea-shell-treated green tea extract with a refreshing flavor was obtained.

<Example 3>
Green tea extract after addition of 0.6% by weight of tea husk 5 to the test green tea extract 3.45 minutes, 7.30 minutes, 15 minutes, 30 minutes, 60 minutes, 120 minutes, 240 minutes after addition The supernatant was collected and used as a tea-shell-treated green tea extract. Note that the temperature of the green tea extract to which the tea husk was added was maintained at 25 ° C.
Each component (gallate-type catechins, non-gallate-type catechins and caffeine) was quantified by HPLC for each tea-shell-treated green tea extract. The results are shown in Table 5. The amount of tea husk added is 0, which is the green tea extract before the addition of the tea husk (green tea extract for testing). FIG. 4 is a graph showing the change rate (%) of each component in the green tea extract with respect to the addition time of the tea husk.

<Example 4>
To the green tea extract for testing, 0.6% by weight of tea husk 5 was added, and the supernatant of the green tea extract after 30 minutes was collected to obtain Extract 4-1 (tea husk-treated green tea extract).

<Comparative example 2>
In Example 4, the test was conducted using polyvinyl polypyrrolidone (PVPP) (trade name Daibagan F, manufactured by BASF) instead of the tea husk 5.
Add 0.03%, 0.05%, 0.1%, 0.2%, and 0.3% by weight of PVPP to the green tea extract for testing. The supernatant was collected and used as comparative extracts 2-1 to 2-5.

Each component (gallate catechins, non-gallate catechins and caffeine) was quantified by HPLC in the extract 4-1 of Example 4 and the comparative extracts 2-1 to 2-5 of Comparative Example 2. The results are shown in Table 6. In addition, the rate of change (%) of each component and the ratio of the rate of change of gallate catechins to the rate of change of non-gallate catechins (change rate of non-gallate catechins / change rate of gallate catechins) Is shown in Table 6.
FIG. 5 is a graph showing a change rate (%) of each component by addition of tea husk or PVPP. Comparisons 2-1 to 2-5 in FIG. 5 are comparison extraction solutions 2-1 to 2-5.

In Table 6, before addition is a green tea extract (green tea extract for testing) before adding tea husk or PVPP.
The ratio of the rate of change of gallate catechins to the rate of change of non-gallate catechins (change rate of non-gallate catechins / change rate of gallate catechins) was 0.38 in Example 4 in which tea shells were added. However, in Comparative Example 2 to which PVPP was added, it was 0.70 to 0.80. In Comparative Example 2 in which PVPP was added, non-gallate catechins were further reduced as compared with Example 4 in which tea husk was added.

According to the present invention, gallate catechins contained in a green tea extract or a green tea beverage can be reduced safely and selectively, and astringency can be reduced.

Claims (11)

A method for producing a green tea extract, comprising a step of bringing a raw material green tea extract into contact with a tea shell. The production method according to claim 1, wherein the tea husk is tea husk having an extraction rate of 20% or more. The manufacturing method of Claim 1 or 2 whose tannin content of a tea-shell is 1 to 10 weight% in dry weight. The manufacturing method as described in any one of Claims 1-3 whose temperature of the raw material green tea extract made to contact with a tea shell is 0-50 degreeC. Ratio of dry weight of tea husk (A) and total weight (B) of gallate catechins and non-gallate catechins in raw green tea extract (A) / The manufacturing method as described in any one of Claims 1-4 whose (B) is 1-100. The manufacturing method as described in any one of Claims 1-5 whose time of the process which makes a raw material green tea extract and a tea shell contact is 1-180 minutes. The manufacturing method according to any one of claims 1 to 6, wherein the tea shell is a green tea tea shell. The manufacturing method as described in any one of Claims 1-7 including the process of removing a tea-shell from a green tea extract. A packaged green tea beverage comprising the green tea extract produced by the production method according to any one of claims 1 to 8. A method for reducing gallate-type catechins in a green tea extract, comprising a step of bringing a raw material green tea extract into contact with a tea shell. A method for reducing the astringency of a green tea extract, comprising a step of bringing a raw material green tea extract into contact with a tea shell.

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