Production method for packed green tea beverage and richness improving method for packed green tea beverage

Abstract

To produce a packed green tea beverage, in which a density feeling and richness can be felt, and further preferably precipitation does not occur after an extended time has elapsed, and aroma emittance can be felt at first taste.SOLUTION: A production method for packed green tea beverage includes: extracting green tea leaves in an aqueous solvent; obtaining a tea extract of the total nitrogen concentration of 20-60 mg / 100 ml; and filtering the obtained tea extract with a filter aid having 5-30 μm of median size (D50) in the cumulative distribution (on the basis of volume) of particle size after swelling.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a green tea beverage containing as its main component a green tea extract extracted from green tea, a method for producing a packaged green tea beverage by filling this green tea beverage in a container such as a plastic bottle, and a method for improving the body of the packaged green tea beverage. [Background technology]

[0002] Green tea beverages contain water-insoluble solids such as polysaccharides and proteins, as well as extraction residues. When filled into transparent containers, these appear as cloudiness, which does not pose a quality problem but is undesirable in appearance. The turbidity that occurs during storage after filling the container can take the form of floating matter, cloudiness, flocs (cotton-like), or sediment, and is collectively known as "sediment."

[0003] As a method for removing such sediment-causing substances in the production of green tea beverages, for example, Patent Document 1 discloses a method in which tea is extracted with hot water, the resulting tea extract is cooled, tannic acid is added, the extract is allowed to stand, fine tea particles are removed by centrifugation or the like, and the extract is then clarified by diatomaceous earth filtration. Patent Document 2 discloses a method in which ascorbic acid is added to a tea extract obtained by extracting green tea to make it acidic, followed by rapid cooling, centrifuging, and then filtering through diatomaceous earth to clarify the extract.

[0004] Patent Document 3 discloses a new manufacturing method suitable for packaged green tea beverages to be sold heated, which includes an extraction step in which green tea leaves are extracted with heated water at 70 to 100°C, an adsorption step in which silica is added to the obtained tea extract to adsorb sediment components in the tea extract onto the silica, a silica removal step in which the silica is removed from the tea extract, a sterilization step, and a container filling step.

[0005] Patent Document 4 discloses a method for producing a packaged green tea beverage, characterized in that the sugar concentration (the sum of the reducing sugar concentration and the non-reducing sugar concentration) in the green tea beverage is adjusted to 50 ppm to 250 ppm, the ratio of the non-reducing sugar concentration to the reducing sugar concentration (non-reducing sugar / reducing sugar) is adjusted to 8 to 24, and the particle size of 90% cumulative mass (D90) is adjusted to 3500 μm or more by filter cake filtration using either or both of a silica-containing filter agent and a porous medium, in order to provide a packaged green tea beverage that has a strong, fragrant aroma, a long-lasting aroma, few impurities, is transparent, and can be enjoyed even when cold. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-269246 [Patent Document 2] Special Publication No. 7-97965 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-229918 [Patent Document 4] WO2012-29131 publication Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional clear green tea beverages have been designed and manufactured with a focus on aroma. Furthermore, for the raw tea used in clear green tea beverages, the effective components must be extracted in a short time for efficient production, so research has focused primarily on improving the elution rate. Meanwhile, improvements to the manufacturing process, such as filtration, have also been considered to remove sediment-causing substances and maintain the clarity of the beverage. In recent years, there has been a trend toward flavor variations, such as a strong "richness" in addition to a strong "aroma" in clear green tea beverages. Furthermore, there is also a trend toward a strong aroma that does not settle over time and that emerges as an initial flavor. However, as mentioned above, it has not been easy to remove the substances that cause sediment and maintain the clarity of green tea beverages while enhancing their richness.

[0008] The first object of the present invention is to propose a method for producing a packaged green tea beverage and a method for improving the richness of a packaged green tea beverage, which can produce a packaged green tea beverage that has a rich aftertaste due to its umami and aroma while removing substances that cause sediment and maintaining the clarity of the green tea beverage.The second object of the present invention is to propose a method for producing a packaged green tea beverage that, in addition to the first object, has a flavor that is perceived immediately after putting the beverage in the mouth, and that maintains a good persistence of the flavor that is perceived immediately after putting the beverage in the mouth, even after aging, or a method for producing a packaged green tea beverage that does not produce an oxidative deterioration odor or produce sediment immediately after production or after aging. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention proposes the following aspects.

[0010] [1] A first aspect of the present invention is a method for producing a packaged green tea beverage, comprising extracting green tea leaves with an aqueous solvent to obtain a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL, and filtering the tea extract through a filter aid having a median diameter (D50) of 5 to 30 μm in the cumulative particle diameter distribution (volume basis) after swelling.

[0011] [2] A second aspect of the present invention is a method for producing a packaged green tea beverage according to the first aspect, wherein the filter aid is derived from a mineral. [3] A third aspect of the present invention is the method for producing a packaged green tea beverage according to the first or second aspect, wherein the filter aid has a Darcy of 0.11 to 0.25. [4] A fourth aspect of the present invention is a method for producing a packaged green tea beverage according to any one of the first to third aspects, wherein the filter aid has a cumulative particle size distribution (volume basis) D90 after swelling of 20 to 60 μm. [5] A fifth aspect of the present invention is a method for producing a packaged green tea beverage according to any one of the first to fourth aspects, wherein the filter aid has a ratio (D90 / D50) of D90 to D50 of the cumulative distribution (volume basis) of particle sizes after swelling of 1.0 to 6.0.

[0012] [6] A sixth aspect of the present invention is a method for producing a packaged green tea beverage according to any one of the first to fifth aspects, wherein the tea extract has a median diameter (D50) of 2 to 20 μm in the cumulative particle diameter distribution (volume basis) of particles contained in the liquid. [7] A seventh aspect of the present invention is the method for producing a packaged green tea beverage according to any one of the first to sixth aspects, wherein the tea extract has a potassium content of 25 to 70 mg / 100 mL. [8] An eighth aspect of the present invention is a method for producing a packaged green tea beverage according to any one of the first to seventh aspects, wherein the tea extract has a gallate-type catechin content of 30 to 200 mg / 100 mL. [9] A ninth aspect of the present invention is a method for producing a packaged green tea beverage according to any one of the first to eighth aspects, wherein the tea extract contains particles whose cumulative particle size distribution (volume basis) D90 to D50 ratio (D90 / D50) is 2.0 to 10.0.

[0013]

[10] A tenth aspect of the present invention is a method for improving the body of a packaged green tea beverage, comprising extracting tea leaves with an aqueous solvent to obtain a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL, and filtering the tea extract through a filter aid having a median diameter (D50) of 5 to 30 μm in the cumulative particle diameter distribution (volume basis) after swelling. [Effects of the Invention]

[0014] According to the method for producing a packaged green tea beverage and the method for improving the body of a packaged green tea beverage proposed by the present invention, it is possible to provide a packaged green tea beverage that has a rich aftertaste due to its umami and aroma while maintaining the clarity of the green tea beverage by removing substances that cause sediment.It is also possible to provide a packaged green tea beverage that has a good flavor sensed immediately after sipping the beverage and that has a good persistence of the flavor sensed immediately after sipping the beverage, or a packaged green tea beverage that does not produce an oxidative deterioration odor or sediment immediately after production or over time. DETAILED DESCRIPTION OF THE INVENTION

[0015] An example of an embodiment of the present invention will be described below, but the present invention is not limited to the embodiment described below.

[0016] <<Production method of the present invention>> A method for producing a packaged green tea beverage according to one embodiment of the present invention (also referred to as the "production method of the present invention") comprises extracting green tea leaves with an aqueous solvent to obtain a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL (extraction step), removing extraction residue from the tea extract as needed (coarse filtration step), centrifuging the tea extract as needed (centrifugation step), filtering the tea extract using a specified filter aid (filtration step), and then producing a packaged green tea beverage via a blending step, sterilization, and container filling steps.

[0017] However, this manufacturing process is merely an example, and the order of the steps can be changed, or other steps can be inserted between the steps.

[0018] According to the production method of the present invention, it is possible to produce a packaged green tea beverage that has a rich aftertaste due to its umami flavor and aroma, and therefore the production method of the present invention can also be used as a method for improving the richness of packaged green tea beverages.

[0019] <Raw material tea> The green tea leaves, i.e., raw tea leaves, can be any type of tea as long as they are picked from the tea plant (scientific name: Camellia sinensis), regardless of the variety, place of origin, picking time, picking method, cultivation method, etc. Raw tea leaves (including leaves and stems) can also be used as raw tea leaves. Furthermore, raw tea leaves can also be used as raw tea leaves that have been subjected to crude tea processing, such as steaming or roasting, to stop enzyme activity. As crude tea, any type of tea can be used as the raw material, such as sencha, kamairicha, kabusecha, gyokuro, tencha, matcha, bancha, roasted tea, steamed tamaryokucha, kamairosei tamaryokucha, Ureshinocha, Aoyagicha, etc. Two or more types of these crude teas may be combined, or flavorings may be added.

[0020] In particular, from the viewpoint of obtaining a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL, it is preferable to use raw tea leaves that satisfy the standard of a total nitrogen concentration of 4 g / 100 g or more as the raw material tea leaves for the production method of the present invention. Examples of such raw tea leaves include teas rich in amino acids, such as first-season tea, gyokuro, and kabusecha. Of these, from the viewpoint of making it easier to prepare a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL, it is even more preferable to use raw tea leaves that satisfy the standard of a total nitrogen concentration of 5 g / 100 g or more or 7 g / 100 g or less, and of which 6.4 g / 100 g or less.

[0021] <Extraction process> The green tea leaves are preferably extracted with a water-soluble solvent at 70 to 100°C. The extraction method can be any currently known extraction method. For example, extraction can be performed using an extraction device called a kneader in accordance with conventional methods, using a water-soluble solvent in an amount 20 to 100 times the amount of raw tea, at 70 to 100°C, for about 1 to 10 minutes at normal pressure, stirring once or several times as necessary. However, the extraction method and extraction conditions are not particularly limited, and for example, drip extraction using a dripper or pressurized extraction can also be performed.

[0022] Examples of the water-soluble solvent used for extraction include pure water (including hard water, soft water, and ion-exchanged water), as well as an ascorbic acid-containing aqueous solution and pH-adjusted water. From the viewpoint of obtaining a tea extract with a total nitrogen concentration of 20 to 60 mg / 100 mL, the amount of water-soluble solvent to be brought into contact with the raw material tea is preferably 20 to 60 times the amount of the raw material tea, more preferably 25 times or more or 50 times or less, and even more preferably 30 times or more or 45 times or less. The extraction temperature, i.e., the temperature of the hot water used for extraction, may be adjusted to 70 to 100°C. However, from the viewpoint of obtaining a tea extract with a total nitrogen concentration of 20 to 60 mg / 100 mL, extraction at a temperature of 72°C or higher or 99°C or lower, more preferably 75°C or higher or 98°C or lower, and even more preferably 78°C or higher or 97°C or lower. The extraction time, i.e., the time during which the tea leaves are in contact with the water-soluble solvent, is preferably 1 to 9 minutes, more preferably 2 minutes or more or 8 minutes or less, and even more preferably 3 minutes or more or 7 minutes or less, from the viewpoint of obtaining a tea extract with a total nitrogen concentration of 20 to 60 mg / 100 mL.

[0023] [Total nitrogen concentration] As described above, the tea extract obtained by extraction is preferably adjusted to have a total nitrogen concentration of 20 to 60 mg / 100 mL. Components that affect the richness of tea beverages, such as caffeine and amino acids, contain nitrogen, so the total nitrogen concentration in tea extract is an indicator of the content of components that affect the richness. A total nitrogen concentration of 20 mg / 100 mL or more in the tea extract is preferable because it can impart a rich, savory aftertaste, while a total nitrogen concentration of 60 mg / 100 mL or less is preferable because it makes it difficult to perceive unpleasant flavors. From this perspective, the tea extract obtained by extraction is preferably adjusted to have a total nitrogen concentration of 20 mg / 100 mL or more, more preferably 22 mg / 100 mL or more, even more preferably 24 mg / 100 mL or more, and even more preferably 26 mg / 100 mL or more.On the other hand, the total nitrogen concentration is preferably adjusted to 60 mg / 100 mL or less, more preferably 50 mg / 100 mL or less, even more preferably 40 mg / 100 mL or less, and even more preferably 35 mg / 100 mL or less.

[0024] The total nitrogen concentration in the tea extract can be adjusted by selecting the type of tea used as the raw material, the tea season, the fertilization method, etc., or by adjusting the extraction conditions, but is not limited to these. Gyokuro and Ichibancha tea contain a lot of amino acids, which allows for a high total nitrogen concentration. The total nitrogen concentration can also be increased by increasing the extraction temperature or lengthening the extraction time.

[0025] <Rough filtration process> The coarse filtration process is a process for removing extraction residues such as tea leaves and large fine powders. For example, a stainless steel filter, flannel cloth, strainer, or any other filtering method currently used to remove extraction residues can be used.

[0026] The tea extract that has undergone the coarse filtration step may be cooled to about 5 to 40°C as needed, and simultaneously with, or before or after, the tea extract may be adjusted to an acidic pH (pH 4 to 5) by adding ascorbic acid, sodium ascorbate, or the like. Cooling the tea extract or adjusting the acidity of the tea extract not only prevents oxidation of the extracted components, but also precipitates components that cause primary sediment, thereby increasing the efficiency of the subsequent centrifugation step.

[0027] <Centrifugal separation process> The tea extract that has been subjected to the coarse filtration step is preferably centrifuged as needed. Centrifugation may be carried out under conditions of, for example, a flow rate of 200 to 500 L / h and a rotation speed of 5,000 to 20,000 rpm. In this case, the clarity (T%) of the final packaged green tea beverage can be adjusted by changing the flow rate, rotation speed, centrifugal sedimentation area (Σ), etc. As mentioned above, it is preferable to cool the tea extract to about 5 to 40°C before centrifuging, but cooling is not necessarily required.

[0028] Fine powder can be removed by centrifugation, but centrifugation is not always necessary if there is another process that can remove fine powder. By performing centrifugation before the filtration step, the burden of the filtration step can be reduced. For example, the filtration time can be shortened by increasing the permeation flow rate and decreasing the permeation pressure. However, since fine particles can also be removed in the filtration step, it is possible to omit centrifugation when performing the filtration step, although this will increase the burden somewhat.

[0029] Instead of centrifugation, filtration using flannel cloth (flannel filtration), filtration with a stainless steel filter of 80 to 200 mesh, filtration with a back filter of 1 to 100 μm mesh, or treatment to reduce the catechin content with PVPP may be performed. The catechin content reduction treatment using PVPP involves contacting a tea extract with PVPP (polyvinyl polypyrrolidone) having a cross-linked structure, allowing the polyphenols (mainly catechins) to adsorb onto the PVPP, and then filtering the extract using a filter, diatomaceous earth, etc. In this process, the amount of catechins and other substances reduced can be adjusted by adjusting the amount of PVPP added and the contact conditions.

[0030] (Tea extract supplied to the filtration process) The tea extract to be subjected to the next filtration step is preferably adjusted so that the median diameter (D50) of the cumulative particle diameter distribution (volume basis) of particles contained in the extract is 2 to 20 μm. It is preferable that the median diameter (D50) of the cumulative particle diameter distribution (volume basis) of particles contained in the tea extract supplied to the filtration step is 2 μm or more, because the rich aroma can be perceived in the middle of the flavor even after aging, i.e., immediately after sipping the beverage, and continues from the moment the beverage is taken into the mouth.On the other hand, it is preferable that the median diameter is 20 μm or less, because the aroma can be perceived in the first half of the flavor even after aging, i.e., immediately after sipping the beverage. From this perspective, the tea extract to be subjected to the filtration step is preferably adjusted so that the median diameter (D50) of the cumulative particle diameter distribution (volume basis) of particles contained in the extract is 2 μm or more, preferably 3 μm or more, more preferably 4 μm or more, and even more preferably 5 μm or more, and is preferably adjusted so that the diameter is 20 μm or less, more preferably 16 μm or less, more preferably 13 μm or less, and even more preferably 10 μm or less. To adjust the median diameter (D50) of the cumulative particle diameter distribution (volume basis) of particles contained in the tea extract to be subjected to the filtration step to fall within the above range, it is preferable to obtain the required fine particles by adjusting the stirring speed and number of stirrings in the extraction step, and then remove coarse particles using a stainless steel filter in the filtration step, although the method is not limited to this.

[0031] Furthermore, the tea extract to be subjected to the next filtration step is preferably adjusted so that the ratio of D90 to D50 (D90 / D50) of the cumulative particle size distribution (volume basis) of particles contained in the liquid is 2.0 to 10.0. It is preferable that the particle ratio (D90 / D50) contained in the tea extract supplied to the filtration step is 2.0 to 10.0, because the flavor is well-balanced from the first half to the second half even after aging, and the full-bodied aroma can be felt. From this perspective, the ratio of particles contained in the tea extract liquid to be subjected to the filtration step (D90 / D50) is preferably adjusted to 2.0 or more, more preferably 2.5 or more, even more preferably 3.0 or more, and more preferably 10.0 or less, more preferably 6.0 or less, even more preferably 5.0 or less, even more preferably 4.0 or less. In order to adjust the particle size of the tea extract to be subjected to the filtration step to fall within the above range, it is preferable to appropriately select the mesh size of the filter used in the coarse filtration step, for example, although the method is not limited to this.

[0032] Furthermore, the tea extract to be subjected to the next filtration step is preferably adjusted so that the potassium content in the liquid is 25 to 70 mg / 100 mL. The potassium content in the liquid is an indicator of the amount of mineral components, and a potassium content of 25 mg / 100 mL or more is preferable because it provides a rich flavor combined with umami in the middle of the flavor even after aging. On the other hand, a potassium content of 70 mg / 100 mL or less is preferable because it suppresses the bitterness associated with saltiness in the first half of the flavor even after aging. From this viewpoint, the potassium content of the tea extract to be subjected to the filtration step is preferably adjusted to 25 mg / 100 mL or more, more preferably 27 mg / 100 mL or more, even more preferably 29 mg / 100 mL or more, even more preferably 31 mg / 100 mL or more, and more preferably 70 mg / 100 mL or less, even more preferably 69 mg / 100 mL or less, even more preferably 67 mg / 100 mL or less. In order to adjust the potassium content in the tea extract to be subjected to the filtration step to fall within the above range, it is preferable to, for example, select or appropriately mix the tea leaves used for extraction, although the method is not limited to this.

[0033] Furthermore, the tea extract to be subjected to the next filtration step is preferably adjusted so that the content of gallated catechins contained in the liquid is 30 to 200 mg / 100 mL. Here, the content of gallate-type catechins means the total amount or total concentration of the contents of epigallocatechin gallate (EGCg), epicatechin gallate (ECg), gallocatechin gallate (GCg) and catechin gallate (Cg). The content of gallate-type catechins in the liquid is an index of the perceived strength, so a catechin content of 30 mg / 100 mL or more in the tea extract is preferred because it provides a bitter taste suitable for a tea beverage in the middle of the flavor even after aging, whereas a content of 200 mg / 100 mL or less is preferred because it reduces the bitterness in the first half of the flavor even after aging and provides a mellow flavor. From this perspective, the tea extract to be subjected to the filtration step is adjusted so that the content of gallated catechins in the liquid is preferably 30 mg / 100 mL or more, more preferably 40 mg / 100 mL or more, even more preferably 45 mg / 100 mL or more, even more preferably 50 mg / 100 mL or more, and preferably 200 mg / 100 mL or less, even more preferably 170 mg / 100 mL or less, even more preferably 150 mg / 100 mL or less. In order to adjust the content of gallated catechins in the tea extract to be subjected to the filtration step to fall within the above range, it is preferable to adjust the temperature of the water-soluble solvent used for extraction, for example, although the method is not limited to this.

[0034] Furthermore, the tea extract to be subjected to the filtration step may contain the following components, as long as the effects of the present invention are not impaired. That is, the tea extract may contain tannins in an amount of 100 mg / 100 mL or more, preferably 150 mg / 100 mL or more, or 400 mg / 100 mL or less, preferably 300 mg / 100 mL or less. The tea extract may contain 10 mg / 100 mL or more of caffeine, preferably 20 mg / 100 mL or more, or 100 mg / 100 mL or less of caffeine, preferably 80 mg / 100 mL or less. The tea extract may contain 1 mg / 100 mL or more of amino acids, preferably 5 mg / 100 mL or more, or 80 mg / 100 mL or less, preferably 50 mg / 100 mL or less of amino acids.

[0035] The tea extract may contain catechins at a concentration of 50 mg / 100 mL or more, preferably 100 mg / 100 mL or more, or at a concentration of 300 mg / 100 mL or less, preferably 250 mg / 100 mL or less. The amount of catechins is the total amount of eight types of catechins (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), and gallocatechin gallate (GCg)).

[0036] The soluble solids content (Brix) of the tea extract is preferably 0.5 or more, more preferably 0.6 or more, and is preferably 2.0 or less, more preferably 1.5 or less.

[0037] <Filtration process> In the filtration step, the tea extract is filtered using a predetermined filter aid. In this case, it is preferable to use a mineral-derived filter aid from the viewpoint of its effect on the flavor and taste of the green tea beverage. Examples of mineral-derived filter aids include diatomaceous earth derived from fossil minerals, perlite derived from volcanic rock, etc. Among these, diatomaceous earth is preferred in terms of liquid permeability.

[0038] Diatomaceous earth is a soil formed by the accumulation of minute diatom shells formed by the fossilization of phytoplankton known as diatoms that have accumulated on the bottom of oceans and lakes over many years.The diameters of the diatom shells range from a few to several tens of micrometers, and the surface is filled with countless minute holes measuring 0.1 to 1.0 micrometers.This allows a dense cake layer of filter aid to be formed on wire mesh or filter cloth, resulting in clear liquid during filtration. The main component of diatomaceous earth is silica (SiO2), especially amorphous silica, and for use as a filter aid it is generally purified by calcination.

[0039] Diatomaceous earth filtration is a cake filtration that uses diatomaceous earth as a filter aid. The diatomaceous earth filtration method involves forming an auxiliary layer (precoat) made of diatomaceous earth on the surface of the filter carrier, and then, as needed, injecting (body feeding) the diatomaceous earth filtering agent into the raw liquid (tea extract as unfiltered liquid), while feeding the raw liquid (tea extract as unfiltered liquid) to the auxiliary layer. Here, "pre-coating" refers to dispersing an auxiliary agent in a clear liquid before the filtration operation, circulating the liquid, and forming a layer of the auxiliary agent several mm thick on the surface of the filter carrier (e.g., a metal leaf, thick filter pad, laminated metal candle, ceramic candle, etc.). This prevents suspended solids from directly adhering to the filter material and causing contamination, and also improves the clarity of the filtrate. Filtration methods include membrane filtration such as ultrafiltration, microfiltration, precision filtration, reverse osmosis membrane filtration, electrodialysis, and biofunctional membrane filtration, as well as a combination of two or more of these. However, because tea beverages are susceptible to oxygen degradation, in terms of flavor balance, it is more appropriate to use clarifying filtration such as filter cake filtration using a filter aid than the cross-flow method commonly used in membrane filtration and ultrafiltration.

[0040] Diatomaceous earth may be mixed with other filter aids such as silica gel, perlite, cellulose, etc.

[0041] In the filtration step, it is preferable to use a filter aid having a median diameter (D50) of 5 to 30 μm in the cumulative particle diameter distribution (volume basis) after swelling. The use of a filter aid with a D50 of 5 μm or more after swelling is preferred because it allows for a rich aftertaste, while the use of a filter aid of 30 μm or less is preferred because it allows for a smooth drinking experience without any roughness on the tongue. From this viewpoint, the filter aid used has a median diameter (D50) in the cumulative particle diameter distribution (volume basis) after swelling of 5 μm or more, preferably 7 μm or more, more preferably 10 μm or more, and preferably 30 μm or less, more preferably 25 μm or less, more preferably 20 μm or less. The swelling conditions for measuring the cumulative particle size distribution (volume basis) of the swelled filter aid are as follows: 10 g of each filter aid is dispersed in 50 times the amount of pure water, and the filter aid is immersed for 15 minutes to swell.

[0042] The filter aid used preferably has a Darcy of 0.11 to 0.25. A Darcy of the filter aid of 0.11 or more is preferable because the overall richness of the tea components can be felt even after aging, while a Darcy of 0.25 or less is preferable because the generation of sediment over time can be suppressed. From this viewpoint, the Darcy of the filter aid used is preferably 0.11 or more, more preferably 0.13 or more, and even more preferably 0.15 or more, while it is preferably 0.25 or less, more preferably 0.23 or less, and even more preferably 0.20 or less. "Filter aid with Darcy of 0.11 to 0.25" refers to a filter aid with a Darcy permeability K in the range of 0.11 to 0.25. "Darcy permeability K" is an index that indicates the permeability of a filter aid and can be determined by the water permeability method or the air permeability method. Currently, "Darcy" is so commonly used that filter aids can be purchased by specifying this value.

[0043] In the filtration step, it is preferable to use a filter aid having a D90 of 20 to 60 μm in the cumulative particle size distribution (volume basis) after swelling. It is preferable to use a filter aid having a D90 of 20 μm or more after swelling, since it can be produced without losing the freshness of the flavor even after aging.On the other hand, it is preferable to use a filter aid of 60 μm or less, since it can maintain the freshness of the flavor over time. From this point of view, the filter aid used has a D90 of the cumulative particle size distribution (volume basis) after swelling of 20 μ m or more, preferably 25 μ m or more, more preferably 30 μ m or more, more preferably 35 μ m or more.On the other hand, it is preferably 60 μ m or less, more preferably 55 μ m or less, more preferably 50 μ m or less, more preferably 45 μ m or less.

[0044] It is preferable to use a filter aid in which the ratio of D90 to D50 (D90 / D50) of the cumulative distribution (volume basis) of particle diameters after swelling is 1.0 to 6.0. It is preferable to use a filter aid having a post-swelling ratio (D90 / D50) of 1.0 to 6.0, since the richness due to the aftertaste aroma can be stably maintained over time from the time of production. From this point of view, the ratio (D90 / D50) of the particle diameter cumulative distribution (volume basis) of the filter aid used after swelling is preferably 1.0 or more, more preferably 1.5 or more, more preferably 2.0 or more, more preferably 2.5 or more.On the other hand, it is preferably 6.0 or less, more preferably 5.0 or less, more preferably 4.5 or less, more preferably 4.0 or less.

[0045] It is preferable to use a filter aid in which the difference between D90 and D10 (D90-D10) of the cumulative distribution (volume basis) of particle diameters after swelling is 25.0 to 80.0 μm. It is preferable to use a filter aid with a difference between D90 and D10 after swelling (D90-D10) of 25.0 to 80.0 μm, since the richness of the aroma from the first half to the latter half can be stably maintained over time from the time of production. From this point of view, the filter aid used has the difference (D90-D10) between the cumulative particle size distribution (volume basis) D90 and D10 after swelling preferably being 25.0 μ m or more, more preferably 30.0 μ m or more, more preferably 35.0 μ m or more, more preferably 40.0 μ m or more.On the other hand, it is preferably 80.0 μ m or less, more preferably 70.0 μ m or less, more preferably 60.0 μ m or less, more preferably 50.0 μ m or less.

[0046] <Mixing process> In blending, water (hard water, soft water, ion-exchanged water, natural water, etc.), ascorbic acid, sodium ascorbate, sodium bicarbonate, sugars, dextrin, flavorings, emulsifiers, stabilizers, or other flavor-imparting ingredients, or a combination of two or more of these, may be added to adjust the pH, concentration, and taste. For example, the pH may be adjusted to about 6 and the Brix to about 0.3.

[0047] <Sterilization / container filling process> For heat sterilization, canned beverages are reheated (hot packed) as needed, then filled and subjected to retort sterilization (for example, heat sterilization at 121°C for 7 minutes under appropriate pressure (e.g., 1.2 mmHg)). For plastic bottled beverages, UHT sterilization is performed (the prepared liquid is held at 120 to 150°C for 1 to several tens of seconds).

[0048] The above-described manufacturing steps, i.e., the manufacturing process for producing a green tea beverage through the extraction step, coarse filtration step, centrifugation step, filtration step, blending step, sterilization step, and container filling step, are merely examples of the present invention and are not intended to be limiting. For example, the order of the steps may be changed, or other steps may be added.

[0049] The T% (660nm) of the beverage liquid in the packaged green tea beverage after filling is preferably 90.0% or more. If the T% (660nm) is 90.0% or more, high clarity and a refreshing taste are obtained. From this perspective, it is even more preferable that the T% (660nm) of the beverage liquid in the packaged green tea beverage after filling is 93.0% or more. On the other hand, the upper limit can be assumed to be 99.0% or less, and in particular 98.0% or less.

[0050] <<Explanation of terms>> In this specification, when the expression "X to Y" (X and Y are any numbers) is used, unless otherwise specified, it means "X or more and Y or less," as well as "preferably larger than X" or "preferably smaller than Y." Furthermore, when it is expressed as "X or more" (X is any number) or "Y or less" (Y is any number), it also includes the intention that "it is preferable that it is greater than X" or "it is preferable that it is less than Y." [Example]

[0051] The present invention will now be described in further detail with reference to the following examples and comparative examples.

[0052] Example 1 30 g of raw green tea (first flush tea of ​​the Yabukita variety produced in Shizuoka, total nitrogen concentration 5.1 g / 100 g) was extracted with 900 mL of hot water at 70°C using a kneader for 5 minutes to obtain extract A. The total nitrogen concentration of the obtained tea extract A was measured. Next, the obtained tea extract A was roughly filtered through an 80-mesh stainless steel filter, and the roughly filtered tea extract was forced to cool to 30°C, allowed to stand, and then filtered through a flannel cloth with 50 μm openings.

[0053] Next, the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid A to obtain a diatomaceous earth filtered liquid. In this case, the diatomaceous earth filtration was carried out by forming an auxiliary layer (precoat) made of diatomaceous earth on the surface of the filter carrier and sending the tea extract to the auxiliary layer. Filter aid A was diatomaceous earth with a Darcy of 0.16, a D50 of 15.0 μm, a D90 of 40.0 μm, and a D90 / D50 of 2.7 (see Tables 1, 3, and 4).

[0054] Next, the diatomaceous earth filtered liquid and pure water were mixed in a 1:1 ratio, 300 ppm of ascorbic acid was added, and the pH was adjusted to 6 with sodium bicarbonate. After that, the mixture was UHT sterilized (135°C, 30 seconds), cooled on a plate, and filled into transparent plastic containers (PET bottles) at 85°C to obtain a bottled green tea beverage. The cap was then sterilized by inverting for 30 seconds, and immediately cooled.

[0055] The D50 and D90 of the filter aids are the median diameters (D50 and D90) in the cumulative particle size distribution (volume basis) after 10 g of each filter aid is dispersed in 50 times the amount of pure water and immersed for 15 minutes to allow swelling. These measurements were performed using a laser diffraction particle size distribution analyzer SALD-2300 manufactured by Shimadzu Corporation.

[0056] <Example 2> 60 g of the same raw material as in Example 1 was extracted with 900 mL of hot water at 70°C for 5 minutes using a kneader to obtain extract B. In addition, the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid B (see the table for particle size distribution and Darcy, the same applies to other filter aids) to obtain a diatomaceous earth filtered liquid, and a packaged green tea beverage was obtained in the same manner as in Example 1.

[0057] Example 3 A packaged green tea beverage was obtained in the same manner as in Example 1, except that the filtrate obtained after filtering extract B through a filter aid C was filtered through diatomaceous earth to obtain a diatomaceous earth-filtered liquid.

[0058] Example 4 The green tea raw material was changed to a 1:1 mixture of first-season tea and autumn / winter bancha tea of ​​the Yabukita variety from Shizuoka, and 30 g of the green tea raw material was extracted with 900 mL of hot water at 70°C using a kneader for 5 minutes to obtain extract C. Furthermore, the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid B to obtain a diatomaceous earth-filtered liquid, and other than this, a packaged green tea beverage was obtained in the same manner as in Example 1.

[0059] <Example 5> A packaged green tea beverage was obtained in the same manner as in Example 1, except that the filtrate obtained after filtering extract C through a filter aid C was filtered through diatomaceous earth to obtain a diatomaceous earth-filtered liquid.

[0060] <Comparative Example 1> A packaged green tea beverage was obtained in the same manner as in Example 1, except that the green tea raw material was changed to Fukuoka-produced Gyokuro (total nitrogen concentration 6.5 g / 100 g), and 60 g of the green tea raw material was extracted with 900 mL of 70°C hot water using a kneader for 10 minutes to obtain extract J.

[0061] <Comparative Example 2> A packaged green tea beverage was obtained in the same manner as in Example 1, except that the green tea raw material was changed to Shizuoka-grown Yabukita autumn winter bancha tea (total nitrogen concentration 3.8 g / 100 g), and 30 g of the green tea raw material was extracted with 900 mL of 70°C hot water using a kneader for 5 minutes to obtain extract K.

[0062] <Comparative Example 3> A packaged green tea beverage was obtained in the same manner as in Example 1, except that the filtrate obtained after filtering extract A through a filter aid D was filtered through diatomaceous earth to obtain a diatomaceous earth-filtered liquid.

[0063] <Comparative Example 4> A packaged green tea beverage was obtained in the same manner as in Example 1, except that the filtrate obtained after filtering extract A through a filter aid E was filtered through diatomaceous earth to obtain a diatomaceous earth-filtered liquid.

[0064] <Analysis of extract> (total nitrogen concentration) The total nitrogen concentration in the extract was measured using the Kjeldahl method using a Kjeltec 8400 manufactured by Phos Japan Co., Ltd.

[0065] <Beverage liquid T%> The packaged green tea beverages obtained in the Examples and Comparative Examples were shaken well, and 4.0 mL was sampled in a standard glass cell. The transmittance (660 nm) was measured using a Shimadzu UV-1800 ultraviolet-visible spectrophotometer, and the result was expressed as clarity (T%).

[0066] <Sensory evaluation test> Regarding the packaged green tea beverages obtained in the Examples and Comparative Examples, 11 panelists engaged in the manufacture of tea beverages were selected and evaluated based on the following evaluation method. After deliberation, it was decided to adopt the most popular evaluation, and for the overall evaluation, the above-mentioned evaluations were scored to calculate an overall score and evaluate whether the problem in this case was solved.

[0067] The evaluation items for each sensory evaluation are as follows: "Richness due to umami in the aftertaste" was evaluated as the lingering umami flavor remaining on the tongue after swallowing the packaged green tea beverage, and "richness due to aroma in the aftertaste" was evaluated as the lingering aroma that escaped from the mouth to the nostrils after swallowing.

[0068] (Rich umami aftertaste) 4: Very good, with a strong umami aftertaste. 3: Good, with a rich aftertaste 2: The richness of the aftertaste is slightly weak or strong, but there is a slightly unpleasant aftertaste. 1: The richness of the aftertaste is either weak or strong, but the off-flavors are noticeable and inappropriate.

[0069] (Rich aroma in the aftertaste) 4: Very good, with a strong aftertaste and rich aroma. 3: Good, with a rich aroma in the aftertaste 2: The aftertaste is slightly weak or strong, but the taste is rough on the tongue and undesirable 1: The aftertaste aroma is either weak or strong, but the roughness on the tongue is noticeable, making it unsuitable.

[0070] [Table 1]

[0071] (Consideration) From the results of the above Examples and Comparative Examples, as well as the results of tests conducted by the inventors up to now, it has been found that by adjusting the type of green tea leaves, the tea season, the extraction conditions, etc. to obtain a tea extract with a total nitrogen concentration of 20 to 60 mg / 100 mL, and filtering the obtained tea extract through a filter aid with a median diameter (D50) of 5 to 30 μm in the cumulative particle size distribution (volume basis) after swelling, it is possible to produce a packaged green tea beverage that has a delicious aftertaste and a rich aroma. In this case, it was found that the desired packaged green tea beverage could not be produced simply by adjusting the total nitrogen concentration of the extract, nor could the desired packaged green tea beverage be produced simply by adjusting the D50 of the filter aid. It was found that in order to produce the desired packaged green tea beverage, it was necessary to adjust both of these factors.

[0072] In Comparative Example 1, the total nitrogen concentration of the green tea raw materials was high and the amount of green tea raw materials was also large, resulting in a high total nitrogen concentration in Extract J. Although the packaged green tea beverage had a strong richness due to the umami of the aftertaste and the richness due to the aroma, it also had a slightly unpleasant unpleasant taste and a rough texture on the tongue, which is thought to have resulted in a poor evaluation of the richness. In Comparative Example 2, the total nitrogen concentration of the green tea raw material was low, so the total nitrogen concentration of the extract K was low, and the packaged green tea beverage was perceived as having a somewhat weaker richness due to the umami of the aftertaste and the richness due to the aroma, which is thought to have resulted in a poor evaluation of richness. In Comparative Example 3, since the D50 of filter aid D was large, the packaged green tea beverage had a noticeable roughness on the tongue and was unsuitable, which is thought to have resulted in a poor evaluation of body. In Comparative Example 4, since the D50 of filter aid E was small, the packaged green tea beverage was perceived as having a weak richness due to the aftertaste aroma, which was unsuitable, and it is thought that this resulted in a poor evaluation of richness.

[0073] Next, in the method for producing a packaged green tea beverage that allows for a rich aftertaste and a savory aroma as described above, further tests were conducted to produce a packaged green tea beverage that has a good flavor in the early and middle stages even after aging, more specifically, a packaged green tea beverage that has a good flavor that can be felt immediately after putting the beverage in the mouth and that has a good persistence of the flavor that can be felt immediately after putting the beverage in the mouth, even after aging.

[0074] Example 6 34 g of green tea raw material (Gyokuro produced in Fukuoka Prefecture) was extracted with 900 mL of hot water at 70°C using a kneader for 10 minutes to obtain extract D. The total nitrogen concentration of the obtained extract D was measured. Next, the obtained extract D was roughly filtered through an 80-mesh stainless steel filter, and the roughly filtered tea extract was forced to cool to 30°C, allowed to stand, and then filtered through a flannel cloth. The filtrate after filtering through the filter was measured for the contents of potassium, aluminum, and gallate-type catechins contained in the liquid, and the particle size distribution of the particles contained in the liquid was measured to determine D50 and D90.

[0075] Next, the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid A to obtain a diatomaceous earth-filtered liquid. Here, filter aid A was diatomaceous earth with a Darcy of 0.16, a D50 of 15.0 μm, a D90 of 40.0 μm, and a D90 / D50 of 2.7.

[0076] Next, the diatomaceous earth filtered liquid and pure water were mixed in a 1:1 ratio, 300 ppm of ascorbic acid was added, and the pH was adjusted to 6 with sodium bicarbonate. After that, the mixture was UHT sterilized (135°C, 30 seconds), cooled on a plate, and filled into transparent plastic containers (PET bottles) at 85°C to produce a bottled green tea beverage. The cap was then sterilized by inverting for 30 seconds, and the mixture was immediately cooled.

[0077] Example 7 A packaged green tea beverage was obtained in the same manner as in Example 6, except that the green tea raw material was changed to first-grade Yabukita tea grown in Shizuoka, and 22.5 g of the green tea raw material was extracted with 900 mL of hot water at 70°C using a kneader for 5 minutes to obtain extract E.

[0078] Example 8 A packaged green tea beverage was obtained in the same manner as in Example 6, except that the green tea raw material was changed to second-grade tea of ​​the Yabukita variety from Kagoshima, and 56 g of the green tea raw material was extracted with 1,160 mL of hot water at 95°C using a kneader for 8 minutes to obtain extract F.

[0079] Example 9 Extract liquid A was obtained in the same manner as in Example 1, and after rough filtration using an 80-mesh stainless steel filter, it was forcibly cooled to 30°C. Extract liquid A was allowed to stand, and 12 g of PVPP was contacted with it for 30 minutes, followed by filtration using a flannel cloth to reduce the content of gallated catechins using PVPP. A packaged green tea beverage was obtained in the same manner as in Example 6, except that extract liquid G was obtained.

[0080] Example 10 Extract liquid A was obtained in the same manner as in Example 1, coarsely filtered through an 80-mesh stainless steel filter, and then forcibly cooled to 30°C. Extract liquid A, which had been allowed to stand, was then filtered through a 200-mesh stainless steel filter to obtain extract liquid H. A packaged green tea beverage was obtained in the same manner as in Example 6, except that the extract liquid A was obtained in the same manner as in Example 1, coarsely filtered through an 80-mesh stainless steel filter, and then forcibly cooled to 30°C.

[0081] Example 11 Extract liquid A was obtained in the same manner as in Example 1, coarsely filtered through an 80-mesh stainless steel filter, and then forcibly cooled to 30°C. Extract liquid A, which had been left to stand, was then filtered through a bag filter with 1 μm openings to obtain extract liquid I. A packaged green tea beverage was obtained in the same manner as in Example 6.

[0082] <Analysis of extract> The components in the extracts D to I obtained in the examples were analyzed as follows. The same applies to the following examples.

[0083] (total nitrogen concentration) The total nitrogen concentration in the extract was measured using the Kjeldahl method using a Kjeltec 8400 manufactured by Phos Japan Co., Ltd.

[0084] (potassium content) The sample was shaken and extracted with 1% hydrochloric acid to prepare a test solution, which was then introduced into an atomic absorption spectrophotometer to measure the potassium content. Measurement equipment: AA240FS (Agilent Technologies (formerly Varian)) Frame: Air-acetylene Measurement wavelength: 766.5nm

[0085] (aluminum content) The sample was diluted with 1% nitric acid to prepare a test solution, which was then introduced into an ICP emission spectrometer to measure aluminum. Measurement equipment: VISTA-PRO (Agilent Technologies (formerly Varian)) Measurement wavelength: 396.152nm

[0086] (Catechin gallate content) The amount of gallate-type catechins in the extract was measured by high performance liquid chromatography (HPLC, i-Series manufactured by Shimadzu Corporation) under the following conditions, and quantified using a calibration curve method. Column: wakosil3C18HG φ3.0 × 100 mm (Wako Pure Chemical Industries, Ltd.) Column temperature: 40℃ Mobile phase: Phase A 5% acetonitrile (containing 0.1% phosphoric acid) Phase B: 50% acetonitrile (containing 0.1% phosphoric acid) Flow rate: 0.43mL / min Injection volume: 5μL Detection: UV230nm Catechin standard solution: (-)-epigallocatechin gallate (EGCg), (-)-epicatechin gallate (ECg), (-)-gallocatechin gallate (GCg), (-)-catechin gallate (Cg) Gradient program: Table 2

[0087] [Table 2]

[0088] (particle size distribution) The median diameter (D50) and D90 in the cumulative particle size distribution (volume basis) of particles contained in the extract were measured using a laser diffraction particle size distribution analyzer SALD-2300 manufactured by Shimadzu Corporation.

[0089] <Beverage liquid T%> The packaged green tea beverages obtained in the Examples and Comparative Examples were shaken well, and 4.0 mL was sampled in a standard glass cell. The transmittance (660 nm) was measured using a Shimadzu UV-1800 ultraviolet-visible spectrophotometer, and the result was expressed as clarity (T%).

[0090] <Sensory evaluation test> The packaged green tea beverages obtained in the examples and comparative examples were exposed to a heat cycle (12 hours at 40°C and 12 hours at -2°C, repeated for a total of 14 days), and then 11 panelists engaged in the production of tea beverages were selected and evaluated based on the following method. After consensus was reached, the most common evaluation was adopted, and the overall evaluation was calculated by scoring the above-mentioned evaluations to determine whether the second problem of this case was solved.

[0091] The evaluation items for each sensory evaluation are as follows: The "first half of the flavor" was evaluated based on the bitterness, astringency, and aroma immediately after putting the flavor in the mouth, and the "middle half of the flavor" was evaluated based on its persistence.

[0092] (First half of the flavor) ◎: Very good (bitterness, astringency, and aroma are optimal) 〇: Good △: Not desirable

[0093] (Mid-stage flavor) ◎: Very good (maintains the aroma from the first half) 〇: Good △: Not desirable

[0094] [Table 3]

[0095] (Consideration) From the results of the above Examples and Comparative Examples, as well as the results of tests conducted by the inventors up to now, it has been found that by adjusting the components and particle size of the extract, in other words the tea extract to be subjected to the filtration process, it is possible to produce a packaged green tea beverage that retains a good aroma and flavor in the first and middle stages even after aging, more specifically, a packaged green tea beverage that retains a good aroma and flavor immediately after taking a sip of the beverage, and that maintains a good persistence of the aroma and flavor immediately after taking a sip of the beverage, even after aging. Regarding the components of the tea extract, the packaged green tea beverage made with a tea extract containing a high amount of potassium had a bitter taste in the first half of the flavor, while the packaged green tea beverage made with a tea extract containing a low amount of potassium had a weak flavor in the middle.Furthermore, the packaged green tea beverage made with a tea extract containing a high amount of gallated catechins had an astringent taste in the first half of the flavor, while the packaged green tea beverage made with a tea extract containing a low amount of gallated catechins had a weak sense of concentration due to the astringency in the middle of the flavor. Regarding the particle size of the tea extract, the packaged green tea beverage made with tea extract having a large D50 had a diluted first half of the flavor, while the packaged green tea beverage made with tea extract having a small D50 had a diluted mid-flavor due to the texture on the tongue.

[0096] Next, further tests were conducted to produce a packaged green tea beverage that, as described above, has a rich aftertaste and aroma and maintains a good flavor in the early and middle stages even after aging, and in which deterioration in both internal quality and appearance is suppressed during production and over time; more specifically, a packaged green tea beverage that does not produce an oxidative deterioration odor or sediment immediately after production or over time.

[0097] Example 12 30 g of raw green tea (first-grade tea of ​​the Yabukita variety produced in Shizuoka Prefecture) was extracted with 900 mL of hot water at 70°C using a kneader for 5 minutes to obtain extract A. The total nitrogen concentration of the obtained extract A was measured. Next, the obtained extract A was roughly filtered through an 80-mesh stainless steel filter, and the roughly filtered tea extract was forced to cool to 30°C, allowed to stand, and then filtered through a flannel cloth. The filtrate after filtering through the filter was measured for the contents of potassium, aluminum, and gallate-type catechins contained in the liquid, and the particle size distribution of the particles contained in the liquid was measured to determine D50 and D90.

[0098] Next, the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid F to obtain a diatomaceous earth-filtered liquid. Here, filter aid F was diatomaceous earth with a Darcy of 0.17, a D50 of 25.0 μm, a D90 of 65.0 μm, and a D90 / D50 of 2.6.

[0099] Next, the diatomaceous earth filtered liquid and pure water were mixed in a 1:1 ratio, 300 ppm of ascorbic acid was added, and the pH was adjusted to 6 with sodium bicarbonate. After that, the mixture was UHT sterilized (135°C, 30 seconds), cooled on a plate, and filled into transparent plastic containers (PET bottles) at 85°C to produce a bottled green tea beverage. The cap was then sterilized by inverting for 30 seconds, and the mixture was immediately cooled.

[0100] Example 13 A packaged green tea beverage was obtained in the same manner as in Example 12, except that the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid G to obtain a diatomaceous earth-filtered liquid. Here, filter aid G was diatomaceous earth with a darcy of 0.15, a D50 of 15.0 μm, a D90 of 19.0 μm, and a D90 / D50 of 1.3.

[0101] Example 14 A packaged green tea beverage was obtained in the same manner as in Example 12, except that the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid H to obtain a diatomaceous earth-filtered liquid. Here, filter aid H was diatomaceous earth with a Darcy of 1.3, a D50 of 25.0 μm, a D90 of 60.0 μm, and a D90 / D50 of 2.4.

[0102] Example 15 A bottled green tea beverage was obtained in the same manner as in Example 12, except that the filtrate after the flannel filtration was subjected to diatomaceous earth filtration using filter aid I to obtain a diatomaceous earth-filtered liquid. Here, filter aid H was diatomaceous earth with a Darcy of 0.03, a D50 of 12.0 μm, a D90 of 58.0 μm, and a D90 / D50 of 4.8.

[0103] <Beverage liquid T%> The packaged green tea beverages obtained in the Examples and Comparative Examples were shaken well, and 4.0 mL was sampled in a standard glass cell. The transmittance (660 nm) was measured using a Shimadzu UV-1800 ultraviolet-visible spectrophotometer, and the result was expressed as clarity (T%).

[0104] <Sensory evaluation test> The packaged green tea beverages obtained in the Examples and Comparative Examples were evaluated by 11 panelists engaged in the production of tea beverages immediately after production and after two weeks of storage in a dark room at 37°C. Evaluation was carried out by the following method, and after consensus, the most common evaluation was adopted. For the overall evaluation, the above-mentioned evaluations were scored to calculate an overall score, and an evaluation was made as to whether the second problem of this case had been solved.

[0105] The evaluation items for each sensory evaluation are as follows: The "internal substance immediately after production" was evaluated based on whether or not an oxidative deterioration odor (more specifically, a metallic, sour flavor) was detected in comparison with the control, to assess the degree of oxidative deterioration during the production stage, which is caused by the time required for diatomaceous earth filtration and the resulting liquid retention. As a control, a packaged green tea beverage obtained in the same manner as in Example 1, except that extract A after flannel filtration was not subjected to diatomaceous earth filtration, was used. The "appearance and internal quality after aging" were evaluated by exposing the beverages to a heat cycle (12 hours at 40°C and 12 hours at -2°C, repeated for a total of 14 days), and then evaluating the degree of sediment formation in the appearance and the degree of thermal and oxidative deterioration in the internal quality, compared with a control. As controls, samples of the packaged green tea beverages obtained in Examples 12 to 15 were used, which had been refrigerated in a dark room at 5°C for the same period.

[0106] (Internal quality immediately after manufacturing) ◎: Very good (same as control or slight difference) 〇: Good (small difference from control) △: Unfavorable (different from control)

[0107] (Appearance and internal structure after aging) ◎: Very good (slight difference from the control) 〇: Good (small difference from control) △: Unfavorable (different from control)

[0108] [Table 4]

[0109] (Consideration) From the results of the above Examples and Comparative Examples, as well as the results of tests conducted by the inventors up to now, it has been found that by using a filter aid having a particle size and darcy within a suitable range, it is possible to produce a packaged green tea beverage in which deterioration of both the internal quality and appearance during production and over time is further suppressed, and more specifically, a packaged green tea beverage that does not produce an oxidative deterioration odor or sediment immediately after production or over time. Regarding the particle size of the filter aid, the packaged green tea beverages filtered through diatomaceous earth using filter aids with a large D90 exhibited an oxidative deterioration odor over time, while the packaged green tea beverages filtered through diatomaceous earth using filter aids with a small D90 exhibited oxidative deterioration during the manufacturing process. Furthermore, it was found that secondary sediment was generated over time in packaged green tea beverages filtered using diatomaceous earth with a high Darcy filter aid, and that packaged green tea beverages filtered using diatomaceous earth with a low Darcy filter aid lacked the overall concentration expected of a green tea beverage.

Claims

1. A method for producing a packaged green tea beverage, comprising extracting green tea leaves with an aqueous solvent to obtain a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL, and filtering the tea extract through a filter aid having a median diameter (D50) of 5 to 30 μm in the cumulative particle diameter distribution (volume basis) after swelling.

2. The method for producing a packaged green tea beverage according to claim 1 , wherein the filter aid is derived from a mineral.

3. The method for producing a bottled green tea beverage according to claim 1 or 2, wherein the filter aid has a darcy of 0.11 to 0.

25.

4. The method for producing a bottled green tea beverage according to claim 1 or 2, wherein the filter aid has a cumulative particle size distribution (volume basis) D90 of 20 to 60 μm after swelling.

5. The filter aid has a ratio (D90 / D50) of D90 to D50 of the cumulative distribution (volume basis) of particle diameters after swelling of 1.0 to 6.

0. The method for producing a container-packed green tea beverage according to claim 1 or 2.

6. 3. The method for producing a packaged green tea beverage according to claim 1, wherein the tea extract has a median diameter (D50) of 2 to 20 μm in the cumulative particle diameter distribution (volume basis) of particles contained in the liquid.

7. 3. The method for producing a packaged green tea beverage according to claim 1, wherein the tea extract has a potassium content of 25 to 70 mg / 100 mL.

8. 3. The method for producing a packaged green tea beverage according to claim 1, wherein the tea extract has a gallate-type catechin content of 30 to 200 mg / 100 mL.

9. 3. The method for producing a packaged green tea beverage according to claim 1, wherein the tea extract contains particles with a ratio (D90 / D50) of D90 to D50 of the cumulative particle diameter distribution (volume basis) of 2.0 to 10.

0.

10. A method for improving the body of a packaged green tea beverage, comprising extracting tea leaves with an aqueous solvent to obtain a tea extract having a total nitrogen concentration of 20 to 60 mg / 100 mL, and filtering the tea extract through a filter aid having a median diameter (D50) of 5 to 30 μm in the cumulative particle diameter distribution (volume basis) after swelling.

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