JP2013035578A - Tea bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tea bag having a beautiful appearance and that can give a beautiful liquid color to a beverage.SOLUTION: The tea bag includes a bag body made of a sheet having a coating membrane on its base material sheet, and an object to be extracted accommodated in the bag body and makes the covering membrane contain a tea extract of which liquid activity is 0.1-0.4 under normal temperature at 5 mass% of a volatile component.

Description

  The present invention relates to a tea bag.

  In recent years, consumption of tea and coffee tends to increase as their refreshing action and health / nutrient functions such as polyphenols contained therein have attracted attention. Currently, beverages in plastic bottles and metal cans can be drunk directly regardless of time and place, and beverages with enhanced functionality, for example, by adding more tannins. As a result, it has gained an overwhelming market size.

  On the other hand, tea leaves brewed in teapots and extractors still maintain a large market due to their outstanding freshness, but they are not convenient and can be expected to grow at a very high rate. It is gone. Tea leaf tea bags and the like have been proposed and widely used in order to improve the convenience while taking advantage of the goodness of such brewed tea, but the market scale is not yet large. In other words, it can be said that it is difficult to obtain great consumer support simply by improving convenience.

  In view of this, tea bags have been proposed in which new functions are added to enhance added value from a viewpoint different from convenience. For example, by applying a cyclodextrin inclusion compound and a water-soluble polymer in which a fragrance is included in cyclodextrin to a hanging bag or base material for a tea bag, a tea bag ( Patent document 1), by providing a cut or through hole in the upper part of the bag that does not contact tea, and penetrating a rod-like object there, it is self-supporting and does not lose its shape even after extraction. Tea bag (Patent Document 2), and at least two kinds selected from water-soluble collagen, water-soluble glucomannan and banaba leaf extract, combined with roasted barley and tea leaves (Patent Document 3) ) Etc. have been proposed.

Japanese Patent Laid-Open No. 03-240665 JP 2004-331144 A JP 2006-230221 A

By the way, the palatability of beverages such as tea is often influenced not only by taste but also by the light blue color of the beverage. The tea leaves have different light blue depending on various conditions such as the leaf extraction time, production area, and type. Moreover, if it is green tea, it will exhibit a faint green, amber, brown, etc., and if it is a black tea, it will exhibit a faint, pink, red, etc. Apart from the recommendations of experts, such light blue preferences are changing, particularly among younger people, and various light blue tea-like beverages are desired. There is also a desire to enjoy high-quality tea and herbal tea in stylish and high-quality tea bags.
Therefore, the subject of this invention is providing the tea bag which has the beautiful external appearance and can provide the beautiful light blue with respect to a drink.

  The present inventors have a uniform and beautiful appearance by forming a film containing a naturally derived component having a specific property on a base material sheet constituting a bag body of a tea bag. It has been found that when it is immersed in water, the color fades and a beautiful light blue color can be effectively imparted.

That is, the present invention is a bag comprising a sheet having a coating on the surface of the base sheet,
A tea bag comprising an extract contained in the bag body, the film containing a tea extract having a water activity of 0.1 to 0.4 at room temperature when the volatile content is 5% by mass. It is to provide.

  The tea bag of the present invention is covered with a film containing a tea extract having specific properties on the surface of the bag body to contain the extract, and is a uniform and good film. have. Moreover, when it is immersed in hot water etc., the beautiful light blue can be provided with respect to a drink with the discoloration of a tea bag. Thus, according to the present invention, it is possible to provide a tea bag with a high added value that can be enjoyed visually by the appearance change when preparing a beverage and the light blue color of the beverage.

  The tea bag of the present invention comprises a bag and an extract to be stored in the bag. The bag body is comprised from the base material sheet in which the film was formed, and it is preferable that the film exists on the surface of the tea bag and is exposed on the outer surface. The coating contains a tea extract with specific properties. And when a tea bag is immersed in hot water etc. and a drink is prepared, while a film melt | dissolves and discolors, a beautiful light blue is provided with respect to a drink.

  The base sheet constituting the bag body is not particularly limited as long as it is formed by sheeting as a whole by interweaving fibers or weaving fibers or bonding or intertwining the fibers. Non-heat seal type And any of the heat seal types can be used. Specifically, a woven fabric, a nonwoven fabric, paper, etc. can be mentioned.

As the woven fabric and the non-woven fabric, the material is preferably a synthetic fiber such as polylactic acid, polyester, polypropylene, polyethylene, nylon, or a combination of two or more of these synthetic fibers. The basis weight is usually 10 to 50 g / m ² , preferably 10 to 30 g / m ² . The woven fabric preferably has an opening ratio of 30 to 70%, and further 40 to 65%, together with the above-mentioned basis weight.
Further, as the paper, thin paper, papermaking, etc. can be used. The thin paper is made of pulp or pulp / synthetic fiber mixed paper, and has a basis weight of usually 10 to 50 g / m ² , preferably 10 to 30 g / m ² . Papermaking is a mixed paper whose material is 50-100% by mass of synthetic fibers such as polyester, vinylon, polyethylene, polypropylene, etc., and the balance is softwood pulp (NBKP), mercerized pulp, cross-linked pulp, etc. 15 to 25 g / m ² .

  In the present invention, a porous sheet such as a nonwoven fabric or a synthetic resin mesh is preferably used as the base sheet from the viewpoint of liquid permeability. In this case, the coating may cover not only the surface of the base sheet but also the fibers constituting the base sheet.

A film is formed on the surface of the base material sheet constituting the bag body, and the film has a water activity at room temperature (hereinafter also simply referred to as “water activity”) at a volatile content of 5% by mass of 0.1. It contains a tea extract that is ˜0.4. The water activity of the tea extract is preferably 0.15 to 0.36, more preferably 0.18, from the viewpoint of having a uniform and beautiful appearance of the film, and from the viewpoint of light blue colorability when immersed in hot water. ~ 0.3. Here, “water activity (A _W )” means the equilibrium water vapor pressure P in the container when the food component to be measured is sealed in a fixed container at a constant temperature, and the equilibrium water vapor pressure of water under the same conditions. it is a numeric value represented as the ratio between _{P 0 (P / P 0)} . Therefore, the water activity is expressed as A _W = P / P ₀ (“Comprehensive Food Dictionary (Dobunshoin), page 489;“ Food Processing Knowledge ”(Shoshobo), pages 13-17;“ Food and Water Activity ”John A. Troller, JHB Christian, Takashi Hirata, Toru Hayashi, Academic Publishing Center, 1985). In this specification, “volatile matter” is a value calculated from loss on drying at 105 ° C. for 2 hours.

  Incidentally, water contained in food includes bound water and free water. Bound water is strongly bound and bound to food ingredients and does not act as a solvent. On the other hand, free water is not constrained by food components and functions as a solvent, and microorganisms and the like propagate using this water. The more free water, the greater the water activity, and the water activity of pure water with 100% free water is 1. In this sense, the water activity represents the amount of water as free water contained in food and the like, and is an index that represents the properties of the food material. The water activity is generally not greatly affected by the temperature at a room temperature of 15 to 35 ° C., and therefore, in this specification, the water activity in this temperature region is referred to as “water activity at room temperature”.

  The tea extract used in the present invention has a water activity in the range of 0.1 to 0.4, and has a small amount of free water and a large amount of bound water. Therefore, a film containing such a tea extract is not sticky because there is little remaining free water, or the film is continuous on the surface of the base sheet due to the presence of sufficient binding water, so it is uniform and good. The film becomes a smooth film.

  The tea extract used in the present invention contains tea-derived tannins. The tannin content in the solid content of the tea extract is preferably 10 to 100% by mass, more preferably 15 to 100% by mass, and still more preferably 18 to 95% by mass. As used herein, “solid content” refers to a residue obtained by drying at 105 ° C. for 2 hours to remove volatile substances.

  A tea extract having a water activity of 0.1 to 0.4 can be obtained by extraction from tea leaves using a solvent having a water / ethanol volume ratio of 100/0 to 20/80. As the ethanol concentration in the extraction solvent increases, the tannin content in the solid content of the tea extract tends to increase, but when the ethanol concentration reaches 100%, the tannin content in the solid content of the tea extract becomes Decrease rapidly. From this viewpoint, the volume ratio of water / ethanol as the extraction solvent is preferably 90/10 to 25/75, more preferably 85/15 to 30/70.

  Moreover, as the ethanol concentration increases, the obtained tea extract tends to exhibit the original color of the tea beverage. Moreover, when a tea bag having a film containing such a tea extract is immersed in hot water or the like, it can be discolored without leaving a pigment, and the original beautiful light blue color of the tea beverage can be imparted. On the other hand, a tea extract obtained from a solvent having an ethanol concentration of 100% has a color that is far from the original of a tea beverage, and a tea bag having a film containing the tea extract can be immersed in hot water or the like. Since the pigment remains and hardly discolors, it becomes difficult to impart the beautiful light blue color inherent to tea beverages.

The tea leaves used for extraction are not particularly limited as long as they contain tannin, and examples thereof include green tea leaves, black tea leaves, and oolong tea leaves. Examples of the green tea leaves include sencha, bancha, gyokuro, tencha, roasted tea, and stem tea, stick tea, bud tea, and the like. Examples of the tea leaves include Darjeeling, Assam, and Sri Lanka. Examples of the oolong tea leaves include wushuiwa tea, iron kannon, golden katsura, daffodil, oolong, bales, and color types. These can be used alone or in combination of two or more.
Among them, it is preferable to use a green tea extract extracted from green tea leaves containing a large amount of non-polymer catechins from the viewpoint of a uniform and beautiful appearance of the film and light blue colorability when immersed in hot water. Here, “non-polymer catechins” refers to non-epimeric catechins such as catechin, gallocatechin, catechin gallate and gallocatechin gallate and epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate and the like. It is a general term that includes all body catechins, and the content of non-polymer catechins is defined based on the total amount of the above eight types.

As the extraction method, known methods such as kneader extraction, stirring extraction (batch extraction), countercurrent extraction (drip extraction), column extraction and the like can be employed.
The temperature of the extraction solvent is preferably 20 to 95 ° C, more preferably 30 to 85 ° C, and still more preferably 40 to 75 ° C, from the viewpoint of extraction efficiency and flavor of tannin. The extraction magnification, that is, (extraction solvent mass) / (tea leaf mass) is preferably 5 to 40, more preferably 10 to 25, from the viewpoint of extraction efficiency and flavor of tannin. The extraction time is not uniform depending on the extraction method and the extraction scale, but is preferably 2 to 60 minutes, more preferably 5 to 30 minutes.

  In the present invention, a commercially available tannin preparation may be used as the tea extract having a water activity of 0.1 to 0.4. For example, the trade name “Polyphenone” (manufactured by Mitsui Norin Co., Ltd.), the trade name “ Theafranc ”(manufactured by ITO EN), trade name“ Sanphenon ”(manufactured by Taiyo Kagaku) and the like can be mentioned.

  Examples of the tea extract used in the present invention include liquids, slurries, and solids (dried products). Among these, solids are preferably used. As a drying method, a known method such as freeze drying or spray drying can be employed.

In the present invention, tannin content in the dry coating, from the viewpoint with a coating is uniform and beautiful appearance, is preferably 5 to 40 g / m ² per unit surface area, a further 7~35g / m ² Is preferred.

  Moreover, the film may contain a fragrance, a seasoning, a sour agent, a sweetener, a health functional food, or the like as desired.

  Examples of the extract contained in the bag include, for example, green tea leaves, black tea leaves, oolong tea leaves, jasmine tea, Tochu tea leaves, pearl barley tea, hub tea, guava tea, dried ganoderma, dried cinnamon, dried perilla leaves, Examples include brown rice, dried herbs, dried kelp, and dried rice bran. Of these, green tea leaves, black tea leaves, and oolong tea leaves are preferred.

  The tea bag of the present invention can take an appropriate shape. For example, a hanging strap or a member that hooks the bag body on the opening of a container such as a cup can be attached to the bag body.

  In addition, the tea bag of the present invention is sealed with a gas barrier packaging material, for example, an ethylene-vinyl alcohol copolymer resin film, various aluminum vapor depositions, or an aluminum laminate film, and is packaged in a state where air and light are blocked. Is desirable.

Next, the manufacturing method of the tea bag of this invention is demonstrated.
The tea bag of the present invention can be produced by an appropriate method using a tea bag sheet obtained by applying a solution or dispersion containing the tea extract to a base sheet and drying it. For example, although the following method can be mentioned according to the kind of base material sheet, it is preferable to shape | mold so that the film formation surface of a base material sheet may be exposed to the outer surface side of a tea bag.
1) When the base sheet is a non-heat seal type, for example, a predetermined amount of tea leaves are placed on the tea bag sheet, and then passed through two crimping gears that rotate the sheet in such a manner as to wrap the tea leaves. The sheets are bound together, then folded in half, and at the same time the bottom is formed into a W-shaped gusset fold, and then the upper portion of the bag is folded.
2) When the base sheet is a heat seal type, for example, a base sheet made of heat-sealing fibers is used to form a bag by heat sealing, and then a predetermined amount of tea leaves are filled into the bag, and then the bag How to fold the upper part of the body.

  As the solvent contained in the solution or dispersion, water and / or alcohol is preferable, and ethanol is suitably used as the alcohol.

  As a method for applying the solution or dispersion to the base sheet, a usual method such as impregnation, brush coating, curtain coating, spray coating, calendar coating, knife coating, gravure coating, T-die coating, or roll coating is adopted. be able to.

  The tannin concentration in the solution or dispersion is preferably 0.5 to 60% by mass, more preferably 1 to 50% by mass, and the tannin content in the coating is appropriately adjusted so as to be within the above-mentioned range. Can do. With such a concentration, it becomes possible to efficiently remove moisture by heating, and since the fluidity is good with an appropriate viscosity, it can be applied uniformly.

  Drying methods include vented box-type drying equipment by convection heat transfer drying, tunnel drying equipment, band drying equipment, box-type shelf drying equipment by radiant heat transfer drying, tunnel drying equipment, band drying equipment, or conduction heat transfer. A heat drying method such as a rotary drum drying device by drying can be employed. The heating temperature is preferably 20 to 90 ° C., more preferably 30 to 80 ° C., from the viewpoint of suppressing deterioration of the coating. Drying is preferably performed until the volatile content of the sheet is 9% by mass or less. Thereby, it can prevent that a sheet | seat shows adhesiveness and it mutually adheres or blocks.

  For example, a tea bag manufactured by filling green tea into a bag body having a film containing a green tea extract having a water activity of 0.1 to 0.4 has a beautiful color with an appearance of a mountain blown color, When a beverage is prepared by immersing it in hot water or the like, the film dissolves and discolors, and a beautiful light blue color and rich aroma can be imparted to the beverage. Moreover, the tea bag manufactured by filling black tea into a bag body having a film containing a black tea extract having a water activity of 0.1 to 0.4 has a beautiful color of reddish brown in appearance. When a beverage is prepared by immersing it in hot water or the like, the coating dissolves and discolors, and a beautiful light blue color with enhanced reddish brown color can be imparted to the beverage. As described above, the tea bag of the present invention has a high added value that can be visually enjoyed due to a change in appearance when a beverage is prepared and the light blue color of the beverage.

1. Measurement of Tannin The amount of tannin was determined by the iron tartrate method, using polyphenone 70A with a non-polymer catechin content of 94% by mass as a standard solution, and a conversion amount of non-polymer catechins (reference: “green tea polyphenols”). "Functional material effective utilization technology series No. 10 for food and drink". A sample of 5 mL was developed with 5 mL of iron tartrate standard solution, dissolved in 25 mL with a phosphate buffer solution, the absorbance was measured at 540 nm, and the amount of tannin was determined from a calibration curve using non-polymer catechins.
Preparation of iron tartrate standard solution: 100 mg of ferrous sulfate heptahydrate and 500 mg of sodium / potassium tartrate (Rochelle salt) were made up to 100 mL with distilled water.
Preparation of phosphate buffer: 1/15 mol / L disodium hydrogen phosphate solution and 1/15 mol / L sodium dihydrogen phosphate solution were mixed and adjusted to pH 7.5.

2. Measurement of water activity Water activity of various powder samples used as a film forming agent was measured using a water activity meter (CX-2, manufactured by Nippon General Co., Ltd.). A cylindrical plastic sample cup having a height of 1 cm and a diameter of 4 cm was filled with the sample powder and sealed, and the water activity was measured at 25 ° C. The water activity of the saturated aqueous sodium chloride solution at 27.5 ° C. was measured to be 0.751, which almost coincided with the literature value of 0.753 (25 ° C.). The volatile content of various powder samples was measured for the relationship between the volatile content of the powder and the water activity of about 20 kinds of powder samples from the absolute dry state of 0% to the first decimal place to the vicinity of 20%. When the volatile content of the powder was in the range of 0% to 20%, the water activity increased linearly from the 0 point as the volatile content increased, and the behavior reached a nearly constant value, so the volatile content of the powder was 2% For the 20% sample, the water activity at 5% volatile content was calculated by the calculation method of [(water activity measurement value ÷ volatile content of measured sample) × volatile content 5%]. The value of

3. Evaluation of Tea Bag (1) Evaluation of coating state The coating state of the outer surface of the tea bag was evaluated according to the following criteria by visual observation and hand touch.
A: Fine powder is not generated on the surface, the whole is a uniform film, and is not sticky.
B: The film is uneven and mottled.

(2) Color evaluation The appearance color of the tea bag was visually evaluated.

(3) Coloring index evaluation Using the color of the base sheet of the tea bag as a reference, the colorability of the outer surface of the tea bag was visually determined according to the following criteria to obtain a coloring index. Next, after immersing the tea bag in 100 mL of warm water at 40 ° C. for 1 minute, lifting the tea bag from the warm water and air-drying, the color index of the outer surface of the tea bag was visually determined according to the following criteria. The change in the coloring index of the tea bag after soaking and after drying was evaluated.
3: Remarkably colored.
2: Colored.
1: Slightly colored.
0: Same color as the base sheet.

(4) Evaluation of light blue After immersing the tea bag in 100 mL of warm water of 40 ° C. for 1 minute, the tea bag was pulled up from the warm water, and the light blue of the warm water was visually evaluated.

4). raw materials:
The tea extract used in this example is as follows.
1) Green tea extract (dry powder) obtained in Production Example 1
2) Black tea extract obtained in Production Example 2 (dry powder)
3) Commercially available tannin preparation A (Polyphenone 70A, manufactured by Mitsui Norin Co., Ltd.)
4) Commercially available tannin preparation B (polyphenone HG, manufactured by Mitsui Norin Co., Ltd.)

  About each tea extract, the water activity in normal temperature in the case of tannin content in solid content and a volatile content of 5 mass% was measured. The results are shown in Table 1.

Production Example 1
After immersing 10 g of commercially available green tea leaves (sencha, manufactured by Koga Tea Honpo) in water, a mixture of water and ethanol having a volume ratio shown in Table 1 or various solvents of ethanol at 50 ° C. for 30 minutes, No. 2 filter paper The filtrate was dried under reduced pressure and concentrated. The concentrated liquid was dried on a hot water bath at 60 to 80 ° C. to produce a green tea extract (dry powder).

Production Example 2
A black tea extract (dry powder) was produced in the same manner as in Production Example 1 except that black tea (Darjeelin Extra, manufactured by Kataoka Bussan Co., Ltd.) was used instead of green tea leaves.

Example 1
A polytetrafluoroethylene sheet having a width x length x thickness of 150 mm x 250 mm x 1 mm was used as a support, and a 9 cm x 15 cm porous substrate sheet (T-Bag, non-heat seal) was formed thereon as a substrate sheet. Paper, basis weight 12 g / m ² , manufactured by Nippon Daishowa Paperboard Co., Ltd.) was placed. Next, a green tea extract (dried powder) extracted from green tea leaves using water as a solvent is used as a dispersion of 60% by mass, and the tannin content in the dried film is 7.4 g / m ² per unit surface area. As above, it was uniformly applied with a spatula from the top of the substrate sheet. Next, the coated base sheet and the support were dried for 15 minutes at 60 ° C. in an electric dryer in the same state without performing operations such as draining. After drying, the sheet was peeled from the support by hand to obtain a tea bag sheet.
Using the obtained tea bag sheet, 2 g of green tea leaves were packaged to produce a green tea tea bag. The coating state, coloration, coloring index, and light blue color of the beverage were evaluated on the outer surface of the obtained tea bag. The results are shown in Table 1.

Example 2
A tea bag is produced in the same manner as in Example 1 except that a green tea extract (dry powder) obtained from green tea leaves is used with a mixture of water / ethanol (volume ratio) of 75/25 as a solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
A tea bag was produced in the same manner as in Example 1 except that a green tea extract (dry powder) obtained from green tea leaves was used with a 50/50 water / ethanol (volume ratio) solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
A tea bag is produced in the same manner as in Example 1 except that a green tea extract (dry powder) obtained from green tea leaves is used with a mixture of water / ethanol (volume ratio) of 40/60 as a solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5
A tea bag was produced in the same manner as in Example 1 except that a green tea extract (dry powder) obtained from green tea leaves was used with a 30/70 water / ethanol (volume ratio) solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
A tea bag was produced in the same manner as in Example 1 except that a black tea extract (dry powder) obtained from black tea leaves was used with water as a solvent. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7
A tea bag is produced in the same manner as in Example 1 except that a black tea extract (dry powder) obtained from black tea leaves is used with a mixture of water / ethanol (volume ratio) of 75/25 as a solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8
A tea bag was produced in the same manner as in Example 1 except that a black tea extract (dry powder) obtained from black tea leaves was used with a 50/50 mixture of water / ethanol (volume ratio) as a solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9
A tea bag was produced in the same manner as in Example 1 except that a black tea extract (dry powder) obtained from black tea leaves was used with a mixture of water / ethanol (volume ratio) of 40/60 as a solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 10
A tea bag is produced in the same manner as in Example 1 except that a black tea extract (dry powder) obtained from black tea leaves is used with a mixed solution of water / ethanol (volume ratio) of 30/70 as a solvent. did. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 11
A tea bag was produced in the same manner as in Example 1 except that the commercially available tannin preparation A was used. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 12
A tea bag was produced in the same manner as in Example 1 except that the commercially available tannin preparation B was used. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
A tea bag was produced in the same manner as in Example 1 except that a green tea extract (dry powder) obtained from green tea leaves was used with ethanol as a solvent. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2
A tea bag was produced in the same manner as in Example 1 except that a black tea extract (dry powder) obtained from black tea leaves was used with ethanol as a solvent. The obtained tea bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Table 1 shows the following.
In both cases of the green tea extract and the black tea extract, the tannin content in the solid content of the tea extract tended to increase with an increase in the ethanol concentration of the solvent during extraction from tea leaves, but the ethanol concentration was 100 %, The tannin content in the solid content of the tea extract decreased sharply.
The water activity of the commercially available tannin preparation is 0.27 or 0.32, and the same kind as the tea extract obtained with a solvent having a water / ethanol volume ratio of 100/0 to 30/70. confirmed. On the other hand, the water activity of the tea extract obtained with a solvent having an ethanol concentration of 100% exceeded 0.4.

  A coating containing a tea extract having a water activity within the range of 0.1 to 0.4 or a commercially available tannin preparation had a uniform and good coating state. In addition, the tea bag having a film containing such a green tea extract has a yellowish appearance, a so-called beautiful mountain blown color, and the tea bag having a film containing a black tea extract has an appearance. The tea bag having a beautiful black tea color and further having a film containing a commercially available catechin preparation had a beautiful rose color or a calm yellow color. All of these tea bags had a coloring index of 3.

  When a tea bag having a coating containing a green tea extract having a water activity in the range of 0.1 to 0.4 is immersed in warm water for 1 minute, taken out from the warm water and air-dried, the appearance is changed from a bright yellow color to a base sheet. When the color was decolored, that is, expressed as a coloring index, the change was 3 → 0. In addition, a tea bag (coloring index 3) having a highly colored film containing a black tea extract or a commercially available tannin preparation having a water activity in the range of 0.1 to 0.4 is slightly after being immersed in warm water. It became a colored state, that is, the color index changed from 3 to 1. As a result, it was confirmed that almost no pigment remained in any of the tea bags. Further, a tea bag having a film containing a green tea extract or a commercially available tannin preparation B can be used to obtain a green tea drink having a beautiful light blue color and aroma with a fading color, and a tea having a film containing a black tea extract. The bag was confirmed to provide a black tea-colored tea beverage having a beautiful light blue color. Due to such a change in the appearance of the tea bag and the light blue color of the beverage, it was possible to enjoy not only the aroma of tea but also visually.

  On the other hand, a tea bag having a coating containing a green tea extract or a black tea extract having a water activity exceeding 0.4 has a non-uniform and mottled coating (coating state evaluation; B), and the tea bag is made warm. It remained colored even after immersion (coloring index 3 → 2). As a result, the tea bag having a film containing a tea extract having a water activity exceeding 0.4 cannot recognize the remaining of the pigment, and cannot sufficiently impart a beautiful light blue color to the beverage along with the color fading. It was.

Claims (4)

A bag made of a sheet having a coating on the surface of the base sheet;
Comprising an extract contained in the bag,
A film is a tea bag which contains the tea extract whose water activity in normal temperature when a volatile content is 5 mass% is 0.1-0.4.   The tea bag according to claim 1, wherein the tea extract is obtained by extraction from tea leaves using a solvent having a water / ethanol volume ratio of 100/0 to 20/80. The tea bag of Claim 1 or 2 whose tannin content in a film is 5-40 g / m < ² > per unit surface area.   The tea bag according to any one of claims 1 to 3, wherein the extract is a tea leaf selected from green tea leaves, black tea leaves, and oolong tea leaves.