TWI879655B - Producing method and processing method of tea product for making cold brew tea - Google Patents

Abstract

The present invention aims to provide a tea product for making cold brew tea from unshattered tea leaves. The present invention also provides a method for producing a tea product for making cold brew tea, which includes a soaking process of soaking the unshattered and unextracted dried tea leaves in water and a freeze drying process of freeze-drying the soaked tea leaves after the soaking process.

Description

Manufacturing method and processing method of tea leaf product for cold brew tea beverage

The present invention relates to a manufacturing method and a processing method of a tea product for cold brew tea beverage.

Tea beverages are extracts obtained from tea leaves using water (H ₂ O) or the like.

The water used for extraction is usually hot water (e.g. water above 80°C) or warm water (e.g. water between 50 and 70°C), but in recent years, extraction with lower temperature water has also become popular. Extraction using such low temperature water is called "cold brewing".

On the other hand, during cold brewing, the extraction efficiency of the components in the tea leaves is low, and a long extraction time (eg, several hours or more) is required.

Therefore, various tea products have been proposed for achieving short-term cold brewing. For example, such tea products are formed by crushing tea leaves and only pouring water to obtain cold brew tea beverages (e.g., Patent Documents 1 and 2).

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 06-217695

[Patent Document 2] Japanese Patent Publication No. 01-108939

[Problem to be solved]

Here, as mentioned above, the tea leaf product for cold brewing tea is prepared by pouring water into a shaped object of tea leaf powder, and directly drinking it as a tea beverage. That is, the tea leaf product for cold brewing tea allows people to absorb all the ingredients contained in the tea leaf.

However, the inventors of this case found that because tea leaves also contain ingredients that have a tainted taste and astringent flavor, tea beverages obtained from conventional tea leaves for cold brewing may not be tasty.

Therefore, the inventors of the present invention aim to develop a tea product for cold brewing tea that can achieve excellent extraction efficiency of components in tea leaves even without crushing the tea leaves.

The present invention is proposed in view of the above situation, and its purpose is to use un-crushed tea leaves to provide a tea product for cold brewing tea with excellent component extraction efficiency.

[Methods of solving the problem]

As a result of the research, the inventors of this case found that in the manufacturing method of tea products for cold brew tea, the above-mentioned problem can be solved by soaking a certain amount of dried tea leaves in water and then freeze-drying them, thereby completing the present invention. More specifically, the present invention provides the following.

(1) A method for producing a tea product for cold brew tea beverages, the method comprising a soaking step of soaking un-crushed and un-extracted dry tea leaves in water, and a freeze-drying step of freeze-drying the tea leaves after the soaking step.

(2) The method according to (1), wherein in the soaking step, the soaking time of the dried tea leaves is less than 24 hours.

(3) According to the manufacturing method described in (1), in the above-mentioned immersion process, the temperature of the above-mentioned water is below 20°C.

(4) A method for processing a tea product for cold brew tea beverages, the method comprising a soaking step of soaking un-crushed and un-extracted dry tea leaves with water, and a freeze-drying step of freeze-drying the tea leaves after the soaking step.

[Invention Effect]

According to the present invention, un-crushed tea leaves are used to provide a tea product for cold brew tea beverages with excellent component extraction efficiency.

The following describes the implementation aspects of the present invention, but the present invention is not limited thereto.

＜Method for producing tea leaf products for cold brew tea beverage＞

According to the method for producing a tea product for cold brew tea beverage of the present invention (hereinafter referred to as "the production method of the present invention"), the following procedures are included in its aspects.

・A process of soaking water in un-crushed and un-extracted dried tea leaves.

・Freeze drying process to freeze dry the tea leaves after the soaking process.

Tea drinks are tea extracts obtained by extracting various components contained in tea leaves using water (H ₂ O) or the like.

Here, regarding the water used for extraction, it is known that the components extracted from the tea leaves will differ depending on its temperature.

Generally speaking, the higher the temperature of the water, the more efficiently the ingredients in the tea can be extracted in a short time. For example, if high-temperature water is used for extraction, caffeine and the flavor component epigallocatechin gallate will be dissolved, resulting in a tea drink with a strong flavor.

On the other hand, when extraction (cold brewing) is performed with water at a relatively low temperature (e.g., below 25°C), while the dissolution of caffeine, epigallocatechin gallate, etc. is suppressed, theanine (L-Theanine), epigallocatechin (epigallocatechin), etc. are dissolved, resulting in a tea drink with a strong taste.

However, obtaining tea beverages using low-temperature water requires a long extraction time (e.g., several hours), and the extraction efficiency of the components is significantly low.

Therefore, the inventors of this case have devoted themselves to research and found that by processing tea leaves using the above-mentioned procedure, even if low-temperature water is used for extraction, tea products with excellent tea component extraction efficiency can be obtained.

The manufacturing method of the present invention is described in detail below.

(1) Definition

The terms used in the present invention include the following meanings.

In the present invention, the so-called "cold brewing (of tea leaves)" includes extraction with water at a lower temperature than hot water (e.g., water above 80°C) or warm water (e.g., water between 50 and 70°C).

For example, the temperature of water used for cold brewing is preferably below 25°C, more preferably above 0°C and below 20°C, and even more preferably above 4°C and below 10°C. In order to distinguish it from hot water and warm water, water within this temperature range is hereinafter referred to as "water for cold brewing".

In the present invention, the so-called "tea product for cold brew tea beverage" or "tea product for cold brew" includes tea products in any form that can be used for cold brewing. In one aspect of the present invention, the tea product is in the form of a freeze-dried product.

In the present invention, the so-called "cold brew tea beverage" is a tea extract obtained by injecting cold brew water into a cold brew tea product.

However, the present invention is not limited to extracting the tea product obtained by the production method of the present invention with cold brew water, and does not exclude the use of hot water or warm water for extraction.

In the present invention, the so-called "component extraction efficiency" is expressed by the amount of specific components (such as theanine and epigallocatechin) dissolved from tea leaves when tea leaves are extracted with water or the like under the same extraction conditions.

When different tea products are extracted under the same extraction conditions, the more specific ingredients are dissolved from the tea leaves, the higher the extraction efficiency for this ingredient.

In the present invention, "excellent extraction efficiency of components (from tea leaves)" includes, for example, dissolving a larger amount of specific components from tea leaves in a shorter time under the same extraction conditions.

(2) Immersion process

In the maceration process, water is allowed to penetrate the un-crushed, un-extracted dried tea leaves.

(2-1) Uncrushed and unextracted dried tea leaves

In the production method of the present invention, un-crushed and un-extracted dry tea leaves are used as raw materials for obtaining tea products for cold brew tea beverages.

Dried tea leaves can be used alone or in combination of two or more.

(2-1-1) Dried tea leaves

In the present invention, the so-called "dried tea leaves" include any plant parts (leaves, stems, etc.) that are dried as raw materials for tea beverages.

The moisture content of the dried tea leaves is not particularly limited, but is preferably 12% by mass or less, and more preferably 5% by mass or less relative to the dried tea leaves.

The dried tea leaves are not particularly limited to plant species, and for example, may be Camellia sinensis, Camellia taliensis, Camellia irrawadiensis, etc.

The method for drying tea leaves is not particularly limited and can be appropriately selected according to the type of tea beverage to be obtained. For example, the method for making sencha (including rough rolling, rolling, medium rolling, fine rolling, etc.), the method for making pan-fried tea (including rolling, dehydration, stir-frying, etc.). In addition, any drying method used in the production methods of white tea, green tea (oolong tea, pouchong tea, etc.) and black tea (including withering) can also be cited.

The type of dry tea is not particularly limited, and any of unfermented tea, slightly fermented tea, semi-fermented tea, fermented tea, and post-fermented tea may be used.

Examples of unfermented tea include green tea (Sencha, Gyokuro, Kancha, Bancha, Gyokurocha, Tencha, Matcha, Hojicha, etc.).

Examples of slightly fermented teas include Silver Needle White and White Peony.

Semi-fermented teas include pouchong tea and oolong tea.

Examples of fermented teas include black tea.

Post-fermented tea includes Pu'er tea.

Dried tea does not necessarily have to be tea dried by the manufacturer of tea products, but can also be commercially available dried tea.

In one aspect of the present invention, the dried tea leaf is preferably unfermented tea, more preferably green tea.

(2-1-2) Uncrushed dried tea leaves

In the present invention, the so-called "unground dried tea leaves" include dried tea leaves that have not been subjected to a powdering process, a grinding process, etc.

Therefore, powdered tea (dried tea leaves ground into powder) is excluded. However, in the present invention, within the scope of not hindering the effect of the present invention, the powdered tea leaves (e.g., powdered tea (powdered tea produced during the process of brewing tea)) are mixed into the dried tea leaves.

Uncrushed dried tea leaves do not necessarily have to maintain the shape of the leaves, and are included in the tea leaves that have been cut, rolled, etc. into rounded granules, and obtained through the CTC process. In addition, the so-called "CTC process" includes processes that apply various treatments such as "crushing", "tearing", and "curling" to dried tea leaves.

These dried tea leaves are preferred from the viewpoint of enabling efficient infusion as described below.

The length of the cut dried tea leaves and the dried tea leaves produced by the CTC method is not particularly limited, but is usually 0.5 mm or more.

Whether the dried tea leaves are uncrushed dried tea leaves can be determined, for example, by using a sieve. For example, it is preferred to use a sieve with a mesh size of preferably 35 or more (mesh size 500) as specified in ASTM E11. ｍ or less), preferably 40 or more (mesh size 425 m or less) as un-crushed dry tea leaves.

(2-1-3) Unextracted dried tea leaves

In the present invention, the so-called "unextracted dried tea leaves" include dried tea leaves that have not been subjected to any extraction process such as water.

Therefore, tea grounds (residues from tea leaves after extraction) are excluded.

(2-2) Immersion in water

In the maceration process, un-crushed and un-extracted dried tea leaves are steeped in water.

The inventors of this case surprisingly discovered that after this soaking, by freeze-drying the tea leaves (described later), a tea product can be obtained in which the components contained in the tea leaves can be easily extracted even with low-temperature water.

The conditions for soaking the dried tea leaves in water are not particularly limited, as long as the dried tea leaves can be fully immersed in the water. However, long-term soaking will cause excessive outflow of ingredients in the dried tea leaves, so it is best to avoid it.

The entire immersion process does not have to be carried out continuously, but can also be carried out in stages. The immersion conditions (temperature, etc.) in the immersion process do not have to be fixed, but can also be changed in the middle.

The water soaked in the dried tea leaves is not particularly limited as long as it is a liquid containing water. It may be a liquid consisting only of water (H ₂ O) or a liquid containing both water (H ₂ O) and components other than water.

In the latter case, the tea beverage may be mixed with ingredients and amounts as ingredients other than water, as long as the effects of the present invention are not impaired. Examples of such ingredients include antioxidant substances (such as ascorbic acid).

In a preferred embodiment of the present invention, the water used in the soaking process does not contain substances that may decompose or deteriorate the components contained in the dried tea leaves. For example, the water used in the soaking process preferably does not contain enzymes.

The amount of water used to soak the dry tea leaves is not particularly limited, as long as the dry tea leaves can be fully soaked.

The upper limit of the amount of water impregnated in the dry tea leaves is preferably 8 times or less, more preferably 6 times or less, and even more preferably 5 times or less, relative to the dry mass of the dry tea leaves, from the viewpoint of easily preventing excessive outflow of components.

The lower limit of the amount of water for soaking the dried tea leaves is preferably 1 time or more, more preferably 2 times or more, relative to the dry mass of the dried tea leaves, from the viewpoint of facilitating sufficient soaking.

The temperature of the water used to soak the dried tea leaves should not be too high from the perspective of inhibiting the outflow of components in the dried tea leaves.

The upper limit of the water temperature for soaking the dried tea leaves is preferably 20°C or lower, more preferably 15°C or lower, further preferably 10°C or lower, and even more preferably 5°C or lower, from the viewpoint of easily preventing excessive outflow of components.

The lower limit of the water temperature for soaking the dried tea leaves is preferably -4°C or higher, more preferably 1°C or higher, and even more preferably 4°C or higher, from the viewpoint of facilitating sufficient water absorption.

The upper limit of the time for which the dried tea leaves are immersed in water is not particularly limited, but from the viewpoint of easily preventing excessive outflow of components, it is preferably 24 hours or less, more preferably 12 hours or less, more preferably 5 hours or less, more preferably 1 hour or less, more preferably 40 minutes or less, more preferably 30 minutes or less, still more preferably 20 minutes or less, and even more preferably 15 minutes or less.

The lower limit of the time for which the dried tea leaves are immersed in water is not particularly limited, but is preferably 1 minute or longer, more preferably 10 minutes or longer, from the viewpoint of facilitating sufficient water absorption.

The method of soaking the dried tea leaves in water is not particularly limited, as long as the dried tea leaves and water can be in contact, and the following methods are listed, for example. In any method, it is preferably carried out at a low temperature (for example, in an environment below 4°C such as in a refrigerator).

・Put the dried tea leaves and water together in any container (resin container, etc.) and perform static absorption, vibration absorption, etc.

・Use a pressure reducer or press to soak the dried tea leaves in water.

・Use a coating machine or other device to spray water onto the dried tea leaves.

(3) Freeze drying process

In the freeze drying process, the soaked tea leaves are freeze dried.

The freeze drying process can adopt any conditions that can be used in freeze drying of any food product, and generally includes the following steps.

・Freeze the tea leaves after soaking.

・Keep the frozen tea leaves frozen and dry them.

In the above process, the soaking process and the freezing of the tea leaves are preferably continuous (no other process is included between the two processes). In addition, from the perspective of easily suppressing the quality degradation of the obtained tea product, it is best to perform freezing immediately (e.g., within 1 hour) after the soaking is completed.

However, once the tea leaves are frozen, they can be dried in their original frozen state, or they can be stored in a freezer until they are dried.

The freezing conditions of the tea leaves after the steeping are not particularly limited.

The freezing temperature is usually above -30℃ to below -1℃.

The drying conditions of the frozen tea leaves can be appropriately set according to the quality of the tea leaves, the degree of vacuum, etc., and are not particularly limited.

The trap cooling temperature is usually below -45°C.

The vacuum degree reached is usually below 10Pa.

In the freeze drying process, any known device (flask type, drying chamber type, etc.) can be used as a freeze dryer.

(4) Tea products

The freeze-dried tea obtained after the freeze-drying process is equivalent to the tea product for cold-brewed tea beverage in the present invention.

The obtained tea product can be directly used for extraction, etc., to prepare tea beverages, and can also be stored in appropriate packaging.

The obtained tea product can be appropriately processed, for example, formulated into the following forms.

・Leaf-shaped tea products packed in containers

・Tea bag products

・Cup products with tea leaves and filter paper fixed inside

・Tea products for tea brewing machines

(5) Examples of tea beverage preparation

The tea product obtained by the production method of the present invention can be used to prepare tea beverages by any extraction method known in the production method of tea beverages.

However, in order to make the tea product obtained from the production method of the present invention particularly suitable for the preparation of cold brew tea beverages, the following is a description of a preferred preparation example.

The method for preparing tea beverage from tea products is not particularly limited, and any method of bringing tea products into contact with water may be adopted.

However, in order to obtain a cold brew tea beverage, the water in contact with the tea product is preferably cold brew water (as described above).

According to the present invention, due to the excellent component extraction efficiency as described above, a cold brew tea beverage can be obtained in a short time. For example, according to the present invention, a cold brew tea beverage can be obtained with an extraction time of preferably less than 20 minutes, more preferably less than 15 minutes, more preferably less than 10 minutes, and even more preferably less than 5 minutes.

When using conventional tea products, several hours of extraction time are required to obtain cold brew tea beverages (for example, see the comparative example described below).

Therefore, the present invention has important technical significance in greatly shortening the extraction time of cold brew and improving the efficiency of component extraction.

As described above, by using low-temperature water for short-time extraction, the dissolution of caffeine, epigallocatechin gallate, etc. is suppressed while theanine, epigallocatechin, etc. are dissolved, thereby obtaining a cold-brewed tea beverage with a strong taste.

＜Processing method of tea products for cold brew tea beverages＞

As described above, according to the present invention, a tea product for cold brewing with excellent component extraction efficiency can be obtained.

Therefore, the present invention also includes a method for processing a tea product for cold brew tea beverage, which includes the following procedures in one aspect.

・The process of soaking un-crushed and un-extracted dried tea leaves in water.

・Freeze drying process to freeze dry the tea leaves after the soaking process.

[Example]

The present invention is described in more detail below by way of embodiments, but the present invention is not limited to these embodiments.

＜Manufacturing of tea products＞

The tea leaves are processed by the following method to produce tea products.

(1) Preparation of dried tea leaves

Commercially available sencha made from leaves (sprouts) of the tea tree (scientific name: Camellia sinensis) is used as dried tea leaves.

This tea, also known as green tea (unfermented tea), is equivalent to "uncrushed and unextracted dried tea leaves".

(2) Immersion process

Soak the dried tea leaves in water in a rectangular container until they are completely immersed. Use 5 times the amount of water (about 4°C) as the dried tea leaves.

Next, place the dried tea leaves and the container in a refrigerator (about 4°C) and leave them for about 15 minutes to allow the tea leaves to fully absorb water.

(3) Freeze drying process

After the impregnation process is completed, the container is quickly taken out of the refrigerator, placed in a freezer (about -20°C) for freezing, and then placed in a freeze dryer (flask type) to dry it under vacuum conditions.

The freeze drying conditions were set at a trap cooling temperature below -50°C, a vacuum degree below 30Pa, and 24 hours.

(4) Acquisition of tea products

After the freeze drying process is completed, a tea product (freeze dried product) is obtained. This tea product is provided for the following extraction test.

＜Extraction test＞

The obtained tea product was subjected to the following test to evaluate the extraction efficiency of the components.

(1) Sample preparation

・Example: The tea product (freeze-dried product) obtained in the above-mentioned "Production of Tea Product"

・Comparison example: Dried tea leaves obtained in "(1) Preparation of dried tea leaves" in "Production of tea products" above (equivalent to ordinary green tea)

(2) Extraction treatment

Each sample was placed in water (about 10°C) in a container and completely immersed.

Then, the container was placed in a refrigerator (about 4°C), and the tea recovery solution sample (cold brewed tea beverage) was avoided at various time points from 3 minutes to 24 hours after placement.

(3) Component analysis

The contents (component dissolution rates) of epigallocatechin-3-ol (EGC), epigallocatechin-3-ol (EGCG), caffeine, and theanine contained in each solution sample were analyzed using a high performance liquid chromatography (HPLC). Details of the analysis conditions are as follows.

(3-1) Analysis conditions of EGC, EGCG and caffeine

・Device: "Shimadzu LC-20AD system", Shimadzu Corporation

・Security Guard Cartridge C18 (i.d. 4*3mm), Phenomenex

・Column: "Wakopak Navi C18-5" (5 m, id 4.6*150mm), Fuji Film Wako Pure Chemical Co., Ltd.

・Solvent:

(Mobile phase A) DW: acetonitrile: phosphoric acid volume ratio 400:10:1

(Mobile phase B) Methanol:Mobile phase A volume ratio 1:2

・Detector: "SPD-40V" (242nm, EGC; 272nm, EGCG, caffeine), Shimadzu Corporation

・Flow rate: 1mL/min

・Column temperature: 40℃

・Injection volume: 20 L

・Gradient: Refer to the table below

[Table 1] Analysis conditions of EGC, EGCG and caffeine Phase A Moving Phase B Remarks 0~2 minutes 95% 5% -- 2~27 minutes 20% 80% Make the line rise 27~35 minutes Maintain the condition of "2 to 27 minutes" 35.01~43 minutes 95% 5% Stabilize the pressure

(3-2) Analysis conditions of theanine

・Equipment: "Shimadzu LC-20AD, SIL-40C system" (Shimadzu Corporation) was used for the automatic pre-column derivatization of phthalaldehyde

・Security Guard Cartridge C18 (i.d. 4*3mm), Phenomenex

・Column: "Inertsil ODS-4 C18" (3 m, id 4.6*150mm), GL Sciences Co., Ltd.

・Solvent:

(Mobile phase A) 20 mM potassium phosphate buffer (pH 6.4)

(Mobile phase B) DW: acetonitrile: methanol volume ratio 15:45:40

・Detector: "RF-20Axs" (excitation wavelength 350nm, fluorescence wavelength 450nm), Shimadzu Corporation

・Flow rate: 0.8mL/min

・Column temperature: 40℃

・Injection volume: 1 L

・Internal standard substance: glycylglycine

・Gradient: Refer to the table below

[Table 2] Analysis conditions for theanine Phase A Moving Phase B Remarks 0~3 minutes 86% 14% -- 3~15 minutes 65% 35% Make the line rise 15~19 minutes 60% 40% -- 19.01~30 minutes 86% 14% Stabilize the pressure

(3-3) Result

The analysis results are shown in Figure 1.

Figure 1 shows the analysis results of components eluted from the tea leaf product of the embodiment. Figure 2 shows the analysis results of components eluted from the dried tea leaves of the comparative example.

Each result shows the relationship between the dissolution time (the time elapsed from the time the sample was added) and the dissolution rate of each component. In addition, the dissolution rate of the component is expressed as a relative value when the amount of the component extracted from the tea leaves of the "comparative example" in 80℃ hot water for 2 minutes is taken as "100%".

As shown in FIG1 , the tea product obtained by the production method of the present invention can obtain an extract (tea beverage) in which epigallocatechin and theanine are fully dissolved even in a short extraction time of less than 5 minutes in a refrigerator.

This result shows that the tea product obtained by the production method of the present invention has an extremely excellent extraction efficiency of components from tea leaves.

In contrast, as shown in FIG. 2(A), in the comparative example of dried tea (general green tea), the dissolution of the extracted components in the cold storage takes a very long time, and it takes nearly half a day to achieve the same dissolution rate as the tea product obtained by the manufacturing method of the present invention.

Furthermore, for the dried tea leaves of the comparative example, if the extraction is performed at room temperature (about 26° C.) instead of in a refrigerator ( FIG. 2(B) ), the dissolution of the components still takes time. It takes nearly 1 hour to achieve the same dissolution rate as the tea leaves obtained by the manufacturing method of the present invention.

As can be seen from the above, the tea product obtained by the production method of the present invention can significantly shorten the extraction time even if it is extracted with water (about 4° C.), and efficient component extraction can be achieved.

without

FIG1 is a diagram showing the analysis results of the eluted components of the tea product of the embodiment. FIG2 is a diagram showing the analysis results of the eluted components of the tea product of the comparative example.

Claims (4)

A method for producing a tea product for cold brew tea beverage, the method comprising: a soaking process, in which un-crushed and un-extracted dry tea leaves are soaked in water that does not contain enzymes produced by Pycnoporus coccineus; and a freeze-drying process, in which the tea leaves after the soaking process are freeze-dried. The manufacturing method according to claim 1, wherein in the soaking process, the soaking time of the dried tea leaves is less than 20 minutes. The manufacturing method according to claim 1, wherein, in the immersion process, the temperature of the water is below 20°C. A method for processing a tea product for cold brew tea beverage, the processing method comprising: a soaking process, soaking un-crushed and un-extracted dry tea leaves with water that does not contain enzymes produced by Pycnoporus coccineus; and a freeze-drying process, freeze-drying the tea leaves after the soaking process.