Method for producing packaged green tea beverage

Abstract

A main purpose of the present invention is to increase the concentration of tea polyphenol in a beverage and to prevent clogging to shorten the extraction time of a tea extract.　Provided is a method for producing a packaged green tea beverage containing a tea extract obtained by dripwise extraction of tea leaves, the method being characterized in that: first tea leaves and second tea leaves having different water permeability coefficients are used as raw materials, the first tea leaves having a larger water permeability coefficient are put into a drip-type extraction device, and the second tea leaves having a smaller water permeability coefficient are then put into the extraction device; a tea leaf layered structure in which a second tea leaf layer formed from the second tea leaves is layered on a first tea leaf layer formed from the first tea leaves is formed in the extraction device, wherein the water permeability coefficient of the entire tea leaf layer structure is 70-93; an aqueous solvent is supplied to the tea leaf layer structure from above, and the aqueous solvent is withdrawn from below the leaf layer structure to obtain a tea extract; the obtained tea extract is filtered to obtain a filtrate; and the filtrate is blended and sterilized, and a container is filled with same.

Description

Manufacturing method for packaged green tea beverages

[0001] This invention relates to a method for producing packaged green tea beverages.

[0002] Polyphenols contained in green tea (also called "tea polyphenols") have been reported to have diverse physiological functions, including antioxidant, anti-cancer, blood glucose-lowering, blood cholesterol-lowering, and triglyceride-lowering effects. Furthermore, in recent years, there has been a growing demand for "intensity" in green tea beverages as a variation in flavor. From this perspective, there is a growing need for packaged green tea beverages with high concentrations of tea polyphenols.

[0003] Traditionally, the method used to prepare tea extract for packaged green tea beverages involved placing tea leaves and heated extract water into an open-type extraction tank called a kneader, stirring, and then removing the tea extract. However, the kneader method had limitations in increasing the concentration of tea polyphenols. When attempting to further increase the concentration of tea polyphenols using the kneader method, the stirring finely breaks down the tea leaves, resulting in more off-flavors and reduced clarity. As a means of solving these problems, one possible method is to extract tea using a drip-type extractor (also called a "column extractor" or "column-type extractor"), which is used for coffee extraction.

[0004] As a method for producing green tea beverages by drip extraction using a drip-type extractor, for example, Patent Document 1 discloses a method for producing tea extract in which tea leaves and water or hot water are placed in a column extractor so that the ratio B / A of the tea leaf height A to the liquid level B of the water or hot water is 0.8 to 3.3, and then water or hot water is supplied from the top of the column and the tea extract is drawn out from the bottom of the column, adjusting the ratio C / A of the liquid level C to the tea leaf height A at the time of preparation to 0.8 to 3.3.

[0005] Patent Document 2 discloses a method for producing a tea extract, characterized by comprising the following steps (1) to (3): (1) A step of layering multiple teas on a tea holding plate installed in a column-type extractor; (2) A step of supplying extraction water from the lower or upper part of the extractor and bringing the extraction water into contact with the layered teas; (3) A step of discharging the tea extract.

[0006] Patent Document 3 discloses a method for producing a tea extract, which includes the following steps: (S A ) The process of placing tea leaves A into a column extractor, (S B ) A step of supplying extracted water B from the bottom of the extractor, (S C ) A step of supplying extracted water C from the top of the extractor, (S D ) A process of supplying extraction water D from the top while extracting the tea extract from the bottom of the extractor.

[0007] Patent Document 4 discloses a method for producing tea extract, which involves layering three or more tea raw materials on a tea holding plate installed in a column-type extractor, supplying extraction water to the extractor, and discharging the tea extract, wherein the wettability of each of the three or more tea raw materials is compared, and one of the tea raw materials excluding the one with the maximum and minimum wettability is placed in the uppermost layer.

[0008] Japanese Patent Publication No. 2006-197920, Japanese Patent Publication No. 2009-82110, Japanese Patent Publication No. 2010-57377, Japanese Patent Publication No. 2011-139655

[0009] Adopting a drip extraction method offers the advantage of obtaining a tea extract with a higher concentration of tea polyphenols and shortening the manufacturing time compared to the kneader method. However, to further increase the concentration of tea polyphenols, it is necessary to put a larger amount of tea leaves with high extractability, such as tea leaves with a relatively large surface area, into the container. In this case, clogging occurs in the extractor, the extraction time of the tea extract is prolonged, and productivity deteriorates. Furthermore, it has been reported that when using drip extraction, the tea extract tends to turn red.Therefore, the first objective of the present invention is to provide a new method for manufacturing a packaged green tea beverage that can increase the concentration of tea polyphenols in the beverage while preventing clogging and shortening the extraction time of the tea extract. The second objective is to provide a method for manufacturing a packaged green tea beverage that can also prevent the beverage from turning red.

[0010] To solve these problems, the present invention proposes the following embodiments.

[0011] [1] A first aspect of the present invention is a method for producing a packaged green tea beverage containing a tea extract obtained by drip extraction of tea leaves, wherein first tea leaves and second tea leaves having different permeability coefficients are used as raw materials, the first tea leaves with a higher permeability coefficient are put into a drip extractor, the second tea leaves with a lower permeability coefficient are put into the extractor, and a tea leaf layer is formed in the extractor having a configuration in which a second tea leaf layer made of the second tea leaves is stacked on top of a first tea leaf layer made of the first tea leaves, and the total permeability coefficient of the tea leaf layer is 70 to 93, an aqueous solvent is supplied to the tea leaf layer from above, and a tea extract is obtained by drawing out the aqueous solvent from below the tea leaf layer, the obtained tea extract is filtered to obtain a filtrate, and the filtrate is blended, sterilized and filled into containers, the method being characterized by

[0012] The permeability coefficient of the entire tea leaf layer described above was determined by placing each of the above tea leaves into a drip-type extractor (with a pipe diameter of φ4 mm) as described above, and the mass per unit area was 6 g / cm³. ２When a test is conducted in which a tea leaf layer is formed so as to obtain the following, water is supplied to the tea leaf layer from above, and a tea extract is drawn from below the tea leaf layer by its own weight, the permeability coefficient k is obtained by the following formula. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml·g / cm ２ ·s) V: Amount of tea extract drawn (mL) m: Amount of tea leaves (g) S: Water permeable area (cm 2 ) t: Water passing time (s)

[0013] [2] A second aspect of the present invention is a method for producing a container-packed green tea beverage, characterized in that in the first aspect, the following permeability coefficient of the first tea leaves is 60 or more and 90 or less, and the following permeability coefficient of the second tea leaves is 30 or more and less than 60.

[0014] The permeability coefficient of each of the above tea leaves is obtained by the following formula when each tea leaf is put into a drip extractor (the diameter of the extraction pipe is φ4 mm) and a tea leaf layer is formed so that the mass per unit area is 6 g / cm ２ and a test is conducted in which water is supplied to the tea leaf layer from above, and a tea extract is drawn from below the tea leaf layer by its own weight. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml·g / cm ２ ·s) V: Amount of tea extract drawn (mL) m: Amount of tea leaves (g) S: Water permeable area (cm 2 ) t: Water passing time (s)

[0015] [3] A third aspect of the present invention is a method for producing a container-packed green tea beverage, characterized in that in the first or second aspect, the absorbance value (A) of the transmitted light with a wavelength of 660 nm of the tea extract before filtration is 0.12 to 0.22.

[0016] [4] A fourth aspect of the present invention is a method for producing a container-packed green tea beverage, characterized in that in any one of the first to third aspects, the green tea beverage after container filling has a tea polyphenol content of 86 to 200 mg / 100 mL%, a transmittance at 500 nm of 65% or less, and a ratio (580 nm / 780 nm) of the transmittance at 580 nm to the transmittance at 780 nm of 0.85 or more.

[0017] The method for producing a packaged green tea beverage proposed by this invention employs a drip extraction method, which allows for the production of a tea extract with a higher concentration of tea polyphenols compared to extraction by kneader, and also shortens the production time. Furthermore, by introducing a first tea leaf with a higher water permeability coefficient into the extractor, followed by a second tea leaf with a lower water permeability coefficient, a tea leaf layer is formed in the extractor, where a second tea leaf layer consisting of the second tea leaf is stacked on top of a first tea leaf layer consisting of the first tea leaf, and the total water permeability coefficient of the tea leaf layer is between 70 and 93. This increases the concentration of tea polyphenols in the beverage while preventing clogging and shortening the extraction time of the tea extract. Moreover, by adjusting the water permeability coefficients of the first and second tea leaves to a predetermined range, it is possible to prevent the tea extract, i.e., the green tea beverage, from turning red, and to produce a packaged green tea beverage that can be evaluated as having a golden color.

[0018] An example of an embodiment of the present invention will be described below. However, the present invention is not limited to the embodiment described below.

[0019] <<Manufacturing Method of the Present Invention>> A method for manufacturing a packaged green tea beverage according to one embodiment of the present invention (also referred to as "the manufacturing method of the present invention") involves drip extraction of tea leaves to obtain a tea extract (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 predetermined filtration aid (filtration step), and then manufacturing a packaged green tea beverage through a blending step and a sterilization / container filling step. However, this manufacturing process is merely an example. The order of each step can be changed, and other steps can be inserted between each step.

[0020] <Raw tea leaves> As the green tea leaves, i.e., the raw tea leaves, any tea species can be targeted without limitation to the variety, origin, harvesting time, harvesting method, cultivation method, etc., as long as they are leaves picked from the tea tree (scientific name: Camellia sinensis). It is also possible to use fresh tea leaves, etc. (including leaves and stems) as the raw tea leaves. Furthermore, it is also possible to use as the raw tea leaves the rough tea obtained by subjecting these fresh tea leaves, etc. to rough tea processing such as steaming or frying to stop the enzyme activity. Also, the finished tea obtained by subjecting the said rough tea to the currently known finishing processing can be used as the raw tea leaves. As the rough tea, for example, any type such as sencha, pan-fired tea, covered tea, gyokuro, tencha, matcha, bancha, roasted tea, steamed jade green tea, pan-fried jade green tea, kiya tea, aoyagi tea, etc. can be used as the raw tea leaves. Also, two or more of these rough teas may be combined, or they may be made by adding spices.

[0021] (The first tea leaves and the second tea leaves) In the manufacturing method of the present invention, it is preferable to use the first tea leaves and the second tea leaves having different water permeability coefficients, i.e., the first tea leaves having a larger water permeability coefficient and the second tea leaves having a smaller water permeability coefficient.

[0022] Here, the water permeability coefficient of the above tea leaves is determined by the following formula when a test is conducted in a drip extractor (the diameter of the extraction pipe is φ4 mm) by putting each tea leaf and depositing it to form a tea leaf layer so that the mass per unit area is 6 g / cm ２ and supplying water to the tea leaf layer from above and withdrawing the tea extract from below the tea leaf layer by its own weight. k = (V × m) / (t × S) k: The water permeability coefficient in the vertical direction (ml·g / cm ２ ·s) V: The amount of tea extract withdrawn (mL) m: The amount of tea leaves (g) S: The water passing area (cm 2 ) t: The water passing time (s)

[0023] The water permeability coefficient of the tea leaves can be adjusted according to the amount of tea leaves, tea species (first flush tea, autumn and winter bancha, etc.), shape (twisting condition), size, degree of firing (pan-fried / steamed, rough tea / finished tea, heating temperature at the time of finishing), etc.

[0024] The first tea leaves are preferably tea leaves that are not easily clogged, that is, tea leaves with a high water permeability coefficient. Therefore, the water permeability coefficient of the first tea leaves is preferably 60 or more and 90 or less, more preferably 65 or more, and even more preferably 70 or more. On the other hand, since the second tea leaves may be tea leaves that are easily clogged, that is, tea leaves with a low water permeability coefficient, the water permeability coefficient of the second tea leaves is preferably 30 or more and less than 60, more preferably 35 or more, and even more preferably 40 or more.

[0025] The difference in the water permeability coefficient between the first tea leaves and the second tea leaves is preferably more than 0 because the second tea leaves are more likely to obtain tea polyphenols even if the water permeability coefficient is low, more preferably 5 or more, and even more preferably 10 or more. On the other hand, if the water permeability coefficient of the second tea leaves is too low, the tea extract will be clogged in the part of the second tea leaves and cannot be extracted, so it is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less.

[0026] The first tea leaves need to be tea leaves with a relatively high water permeability coefficient. From this perspective, from the perspective of firing, so-called "hard" tea leaves such as pan-fired tea, roasted tea, and finished tea are suitable for the first tea leaves. For example, fully sprouted tea leaves, tea leaves with less kneading in the wild tea manufacturing process, and guricha are suitable. As the tea season, autumn and winter bancha is preferred among ordinary steamed tea leaves. On the other hand, if it is pan-fired tea, ichibancha, nibancha, sanbancha, or autumn and winter bancha may be used. From the perspective of sufficiently leaching tea polyphenols into the extract, ichibancha or nibancha is more preferred.

[0027] The above "pan-fired tea" is tea that has been subjected to a "frying" treatment instead of "steaming" in the fixation process that stops the action of tea leaf enzymes. The above "guricha" is generally not in the shape of long and thin tea like sencha, but is finished as wild tea with a round shape. The above "roasted tea" is tea that has been finished by applying high-temperature heat to wild tea until it has a roasted aroma, and it has the characteristics of less moisture and hardness compared to wild tea and general sencha.

[0028] Regarding the size of the first type of tea leaves, it is preferable that they remain on the surface when sieved through a No. 30 sieve, and even more preferable that they remain on the surface when sieved through a No. 20 sieve. The tea polyphenol content of the first type of tea leaves is preferably 5 to 25 g / 100 g, more preferably 8 to 25 g / 100 g, and particularly preferably 10 to 25 g / 100 g. The content of the eight types of catechins (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), gallocatechin gallate (GCg)) is preferably 4 to 20 g / 100 g, more preferably 6 g / 100 g or more or 20 g / 100 g or less, and particularly preferably 8 g / 100 g or more or 20 g / 100 g or less. Furthermore, the ratio of gallate-type catechins to the eight types of catechins (gallate-type catechins / eight types of catechins) is preferably 10 to 80% by mass, more preferably 20% by mass or more or 70% by mass or less, and particularly preferably 30% by mass or more or 60% by mass or less. The amino acid content is preferably 0.1 to 5 g / 100 g, more preferably 0.1 to 4.5 g / 100 g, and particularly preferably 0.1 to 4 g / 100 g. The total nitrogen content is preferably 2.0 to 10.0 g / 100 g, more preferably 3.0 to 8.0 g / 100 g, and particularly preferably 4.0 to 7.0 g / 100 g.

[0029] On the other hand, the second tea leaf is preferably a tea leaf with a relatively low water permeability coefficient but high extractability of tea polyphenols, such as a tea leaf with a relatively large surface area. From this viewpoint, the second tea leaf is preferably a so-called "soft" tea leaf raw material such as ordinary steamed tea, deep-steamed tea, or extra-steamed tea. From the viewpoint of softness, for example, "young buds" that are picked early, or tea leaves that are kneaded a lot in the crude tea manufacturing process, such as tea leaves that have been kneaded under strong pressure in the kneading process are preferred. From the viewpoint of sufficiently extracting tea polyphenols into the extract, it is preferable that it be first flush or second flush tea. Furthermore, it is preferable that it be crude tea rather than finished tea.

[0030] Furthermore, the "regular steamed tea" mentioned above is tea that has undergone a "steaming" process in the "killing green" stage, which stops the enzyme activity of the tea leaves. It has the characteristic of having softer leaves than "pan-fried tea" and being more likely to absorb moisture and expand. The "deep-steamed tea" and "extremely steamed tea" mentioned above are teas that have undergone a "steaming" process for a long time in the "killing green" stage, which stops the enzyme activity of the tea leaves, within the crude tea process. Because the "regular steaming" structure is broken down, the crude tea has the characteristic of having a finer shape than "pan-fried tea" or "regular steamed tea".

[0031] As mentioned above, the second tea leaf is preferably one with a relatively large surface area, and therefore, it is preferable that it be a fine tea leaf. From this viewpoint, it is preferable to sift the second tea leaf using a No. 4 sieve and remove the tea leaves on the sieve, and among these, it is preferable to sift it using a No. 8 sieve and remove the tea leaves on the sieve. The second tea leaf is preferably a so-called "fine" tea leaf raw material, such as crushed tea or powdered tea.

[0032] The second tea leaf content of tea polyphenols is preferably 10 to 30 g / 100 g, more preferably 12 to 30 g / 100 g, and particularly preferably 15 to 30 g / 100 g. The content of the eight types of catechins (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), gallocatechin gallate (GCg)) is preferably 8 to 24 g / 100 g, more preferably 10 g / 100 g or more or 24 g / 100 g or less, and particularly preferably 12 g / 100 g or more or 24 g / 100 g or less. Furthermore, the ratio of gallate-type catechins to the eight types of catechins (gallate-type catechins / eight types of catechins) is preferably 20 to 90% by mass, more preferably 30% or more by mass or 80% or less by mass, and particularly preferably 40% or more by mass or 70% or less by mass. The amino acid content is preferably 0.1 to 6 g / 100 g, more preferably 0.4 g / 100 g or more or 5 g / 100 g or less, and particularly preferably 0.8 g / 100 g or more or 4 g / 100 g or less. In addition, the total nitrogen is preferably 1.0 to 9.0 g / 100 g, more preferably 1.5 to 7.5 g / 100 g, and particularly preferably 2.0 to 6.0 g / 100 g.

[0033] As mentioned above, in terms of size, it is preferable that the first tea leaves be relatively large and the second tea leaves be relatively small. From this viewpoint, the first tea leaves should be fully grown leaves, for example, tea leaves with a hardening degree of 50 to 70, or tea leaves that have been kneaded less during the crude tea manufacturing process, for example, gyokucha. On the other hand, the second tea leaves should be tea leaves that have been kneaded more during the crude tea manufacturing process, for example, tea leaves that have been kneaded under strong pressure during the rolling process, or so-called "fine" tea leaves such as crushed tea or powdered tea, for example, tea leaves that are picked early and are soft, for example, tea leaves with a hardening degree of 30 to 50.

[0034] The permeability coefficients of the first and second tea leaves can also be adjusted by sieving. For example, by removing the leaves below a No. 30 or No. 20 sieve, i.e., by removing fine tea leaves, the permeability coefficients of the first and second tea leaves can be increased. On the other hand, by removing the leaves above a No. 4 or No. 8 sieve, i.e., by removing larger tea leaves, the permeability coefficients of the first and second tea leaves can be decreased. In this invention, it is desirable to adjust the permeability coefficient of the first tea leaves to be higher than that of the second tea leaves. Therefore, when adjusting the size of the first tea leaves by sieving, it is preferable to remove the leaves below a No. 30 sieve, and more preferable to remove the leaves below a No. 20 sieve. On the other hand, since it is desirable to extract tea polyphenols more efficiently from the second tea leaves than from the first tea leaves, when adjusting the size of the second tea leaves by sieving, it is preferable to remove the leaves above a No. 4 sieve, and more preferable to remove the leaves above a No. 8 sieve.

[0035] The first consideration is the bulk density of the tea leaves, which makes them less prone to becoming compacted and easier to extract from the brewer. Therefore, 0.5 g / cm³ is chosen. ３ Preferably, the following, and especially 0.4 g / cm³ ３ Among them, 0.33 g / cm³ is the most common. ３ It is even more preferable that the following conditions are met. On the other hand, in terms of improving the extractability of tea polyphenols, 0.2 g / cm³ ３ Preferably, the concentration is 0.21 g / cm³ or higher, and more preferably 0.21 g / cm³. ３ Among them, 0.22 g / cm³ ３It is even more preferable if the above is true. On the other hand, the second bulk density of the tea leaves is 0.22 g / cm³, which increases the surface area of ​​the tea leaves and enhances the extractability of tea polyphenols. ３ Preferably, the concentration is 0.24 g / cm³ or higher, and more preferably 0.24 g / cm³. ３ Among them, 0.26 g / cm³ ３ The above is even more preferable. On the other hand, from the viewpoint of making it less likely for the second tea leaf layer to become compacted, 1.0 g / cm³ is preferable. ３ Preferably, the following, and especially 0.6 g / cm³ ３ The following is more preferable, and among them 0.5 g / cm³ ３ The following is particularly preferable:

[0036] <Extraction Process> In the manufacturing method of the present invention, it is preferable to use a drip-type extractor to put the first tea leaves with a higher water permeability coefficient into the extractor and deposit them, then put the second tea leaves with a lower water permeability coefficient into the extractor and deposit them, thereby forming a tea leaf layer in the extractor in which a second tea leaf layer consisting of the second tea leaves is stacked on top of a first tea leaf layer consisting of the first tea leaves, and then supply an aqueous solvent to the tea leaf layer from above and draw out the aqueous solvent from below the tea leaf layer to obtain a tea extract. At this time, it is preferable to form the tea leaf layer such that the water permeability coefficient of the entire tea leaf layer is within a predetermined range.

[0037] One possible method for obtaining a tea extract with a high concentration of tea polyphenols is to place a large amount of tea leaves in the extractor. However, depending on the type of tea leaves, increasing the amount may cause clogging and lengthen the extraction time. In particular, placing a large amount of so-called "soft" tea leaves, such as regular steamed or deep-steamed tea leaves, is prone to clogging. Therefore, by first placing the first tea leaves with a high water permeability coefficient into the extractor, and then placing the second tea leaves with a low water permeability coefficient into the extractor, a tea leaf layer is formed in the extractor with a first tea leaf layer consisting of the first tea leaves and a second tea leaf layer consisting of the second tea leaves, and the water permeability coefficient of the entire tea leaf layer is within a predetermined range, for example, 70 to 93, and then extracting, a tea extract with a high concentration of tea polyphenols can be obtained without clogging, and the extraction time can be shortened.

[0038] (Extractor) In the manufacturing method of the present invention, it is preferable to perform drip extraction using a drip-type extractor. Compared to kneader extraction, drip extraction allows for the extraction of tea-derived components with a smaller amount of hot water, and also allows for the extraction of a larger amount of tea leaves at once, thus shortening the manufacturing time and enabling the extraction of more tea-derived components. Therefore, it is suitable for the industrial production of tea beverages with a high concentration of tea polyphenols. Furthermore, since green tea beverages tend to oxidize and change color from golden to red as the manufacturing time increases, adopting the drip method shortens the extraction time, making it easier to obtain a green tea beverage that is rich in tea polyphenols and has a golden, transparent color. However, simply adopting drip extraction does not solve the aforementioned problems of the present invention.

[0039] A drip-type extractor can be any device that includes a supply means for supplying extraction water from above the extractor, which consists of a closed extraction column; an extraction means for extracting the tea extract from below the extractor; and a tea leaf holding plate for holding tea leaves inside. The means for supplying extraction water to the tea leaf layer inside the extractor can be any device that supplies extraction water from above the tea leaf layer via a shower nozzle or the like. However, it is not limited to a shower nozzle. The means for extracting the tea extract can be any device that discharges the tea extract from an extraction pipe via a valve. The tea extract may be extracted by gravity or by power, such as a pump. The tea holding plate for holding the tea is not particularly limited as long as it can separate the tea leaves from the tea extract. For example, a wire mesh is preferred, and flat, conical, pyramidal, or other shapes can be used. Furthermore, the mesh size of the wire mesh is preferably 20 to 150 mesh, in terms of effectively separating the prepared tea from the tea extract, and more preferably 40 mesh or more or 120 mesh or less, and even more preferably 60 mesh or more or 100 mesh or less.

[0040] (Formation of tea leaf layers) The first tea leaves with a higher water permeability coefficient are placed into the extractor, and the first tea leaves are piled up to form the first tea leaf layer. Then, the second tea leaves with a lower water permeability coefficient are placed into the extractor, and the second tea leaves are piled up on top of the first tea leaf layer to form the second tea leaf layer, thus forming tea leaf layers within the extractor.

[0041] It is preferable to pile the first batch of tea leaves and level the surface so that the height is uniform, then add the second batch of tea leaves, pile them up, and level the surface so that the height is uniform. In this case, a stirring device equipped with a horizontal rod or horizontal blades attached to a vertical rod may be used to level the surface of the tea. However, it is not limited to this method.

[0042] From the viewpoint of sufficiently extracting tea polyphenols, the amount of the first and second tea leaves to be added is preferably 20 parts by mass or more for every 100 parts by mass of the first tea leaves, more preferably 30 parts by mass or more, and more preferably 50 parts by mass or more. On the other hand, from the viewpoint of quality and manufacturing efficiency, in order to shorten the extraction time, the amount of the second tea leaves to be added is preferably 200 parts by mass or less for every 100 parts by mass of the first tea leaves, more preferably 150 parts by mass or less, and more preferably 100 parts by mass or less.

[0043] From a similar viewpoint, it is preferable that the height of the second tea leaf layer in the extractor is 10 or more relative to the height of the first tea leaf layer, which is 100, and more preferably 20 or more, and even more preferably 30 or more. On the other hand, it is preferable that the height of the second tea leaf layer is 200 or less relative to the height of the first tea leaf layer, which is 100, and more preferably 150 or less, and even more preferably 100 or less.

[0044] The permeability coefficient of the tea leaf layer, which is formed by stacking a second layer of tea leaves on top of a first layer of tea leaves, is preferably 70 or higher, more preferably 75 or higher, and even more preferably 80 or higher, from the viewpoint of quality and manufacturing efficiency in order to shorten the extraction time. On the other hand, from the viewpoint of increasing the concentration of tea polyphenols, it is preferably 93 or lower, more preferably 90 or lower, and even more preferably 88 or lower. The permeability coefficient of the tea leaf layer can be adjusted by the permeability coefficients and amounts of the first and second tea leaf layers, respectively.

[0045] The permeability coefficient of the entire tea leaf layer described above was determined by placing each of the above tea leaves into a drip-type extractor (pipe diameter: φ4 mm) as described above, with a mass of 6 g / cm³ per unit area. ２ The permeability coefficient k is calculated using the following formula when a tea leaf layer is formed in such a manner, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from the bottom of the tea leaf layer by its own weight. Note that the drip extractor used in the above test may be different from the extractor used for actual extraction. Similar results can be obtained with any extractor having the specified (extraction pipe diameter: φ4 mm). Furthermore, if the first and second tea leaves used for actual extraction are placed in the extractor in the same ratio as in actual extraction, the permeability coefficient of the entire tea leaf layer measured will be approximately the same as the permeability coefficient of the tea leaf layer formed in actual extraction, even if the drip extractor used in the above test is of a different size than the extractor used for actual extraction.

[0046] k = (V × m) / (t × S) where k is the hydraulic conductivity in the vertical direction (ml・g / cm²). ２ ・s) V: Amount of tea extract (mL) m: Amount of tea leaves (g) S: Water permeability area (cm²) 2 ) t: Water flow time (s)

[0047] To form a tea leaf layer such that the overall permeability coefficient of the tea leaf layer falls within the above range, one can adjust the permeability coefficients of the first and second tea leaves, as well as the amounts of the first and second tea leaves added. However, the method is not limited to these.

[0048] (Aqueous Solvent) Examples of water-soluble solvents used for extraction include pure water (including hard water, soft water, and deionized water), as well as aqueous solutions containing ascorbic acid and pH-adjusted water. The extraction temperature, i.e., the temperature of the water-soluble solvent to be extracted, is preferably adjusted appropriately between 0 and 100°C. From the viewpoint of increasing the concentration of tea polyphenols, a temperature of 70 to 100°C is preferred, and more preferably extraction is performed 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 more preferably 78°C or higher or 97°C or lower.

[0049] (Tea extract extraction speed) The tea extract extraction speed is determined by, for example, the tea leaf separation mesh at the bottom (area 50 cm 2 When using a drip-type cylindrical extractor (φ98 mm) equipped with 80 mesh and extracting from a φ4 mm diameter extraction pipe, from the viewpoint of production efficiency (extraction time), it is preferable that the extraction rate is 550 mL / min or more, more preferably 600 mL / min or more, and even more preferably 700 mL / min or more. The faster the extraction rate of the tea extract, the better, but it is considered difficult to achieve a rate of 5000 mL / min or more. The extraction rate of the tea extract can be adjusted by adjusting the type and amount of tea leaves, as well as the diameter of the outlet pipe, i.e., the diameter of the extraction pipe, suction by a pump, etc., the opening of the valve on the outlet pipe, and the holding time between the primary and secondary showers.

[0050] <Coarse Filtration Process> The tea extract obtained in the extraction process is preferably subjected to coarse filtration to remove extraction residues such as tea leaves and large fine particles, if necessary. For example, stainless steel filters, flannel cloths, strainers, and other filtration methods currently used to remove extraction residues can be arbitrarily employed.

[0051] The tea extract, after undergoing the coarse filtration process, may be cooled to approximately 5-40°C as needed. Simultaneously or before / after this cooling, ascorbic acid or sodium ascorbate may be added to the tea extract as needed to adjust its acidity (pH 4-5). Cooling or adjusting the acidity of the tea extract prevents oxidation of the extracted components and also precipitates primary sediment-causing components, thereby improving the efficiency of subsequent centrifugation processes.

[0052] <Centrifugal Separation Process> The tea extract that has undergone the coarse filtration process is preferably subjected to centrifugal separation as needed. Centrifugal separation can be carried out under conditions such as a flow rate of 200 to 500 L / h and a rotation speed of 5,000 to 20,000 rpm. In this process, the clarity (T%) of the final bottled green tea beverage can be adjusted by changing the flow rate, rotation speed, and centrifugal sedimentation area (Σ). When centrifuging, it is preferable to cool the tea extract to about 5 to 40°C beforehand, as mentioned above, but it is not always necessary to cool it.

[0053] While centrifugation can remove fine particles, it is not always necessary if there are other processes that can remove them. Performing centrifugation before the filtration process can reduce the burden on the filtration process. For example, it can shorten the filtration time by increasing the permeate flow rate and decreasing the permeate pressure. However, since fine particles can also be removed during the filtration process, it is possible to omit centrifugation if the filtration process is performed, although this will slightly increase the burden.

[0054] Alternatively, instead of centrifugal separation, filtration using flannel cloth (flannel filtration), filtration with an 80-200 mesh stainless steel filter, filtration with a back filter with a mesh size of 1-100 μm, or catechin content reduction treatment using PVPP may be performed.

[0055] <Filtration Process> In the filtration process, the tea extract is filtered using a predetermined filtration aid. In this process, it is preferable to use a mineral-derived filtration aid from the viewpoint of its effect on the flavor of the green tea beverage. Examples of mineral-derived filtration aids include diatomaceous earth derived from fossil minerals and perlite derived from volcanic rock. Among these, diatomaceous earth is preferred in terms of its liquid permeability.

[0056] Diatomaceous earth is a soil formed from the fossilization of diatoms, a type of phytoplankton, that accumulate on the seabed or lakebed over many years, resulting in an accumulation of fine diatom shells. With a diameter of several to tens of micrometers, its surface has countless tiny pores ranging from 0.1 to 1.0 micrometers. By forming a dense cake layer of filter aid on wire mesh or filter cloth, a clear liquid can be obtained during filtration. The main component of diatomaceous earth is silica (SiO2), particularly amorphous silica, and for use as a filter aid, it is common to use silica that has been refined by firing.

[0057] Diatomaceous earth filtration is a type of filtrate filtration that uses diatomaceous earth as a filter aid. The method of diatomaceous earth filtration involves forming a layer of diatomaceous earth (precoat) on the surface of the filter carrier, and then, as needed, injecting (body-feeding) the diatomaceous earth filter agent into the raw liquid (tea extract as an unfiltered liquid) while sending the raw liquid (tea extract as an unfiltered liquid) to the precoat. Here, "precoat" refers to the process of dispersing the additive in a clear liquid before the filtration operation, circulating it, and forming a layer of the additive several millimeters thick on the surface of the filter carrier (for example, a metal mesh (leaf), thick filter paper (filter pad), laminated metal ring (candle), ceramic cylinder (candle), etc.). This prevents suspended solids from directly adhering to and contaminating the filter material, and also improves the clarity of the filtrate. Furthermore, various filtration methods are possible, such as ultrafiltration, microfiltration, microfiltration, reverse osmosis filtration, electrodialysis, and membrane filtration using bio-functional membranes, or a combination of two or more of these. However, since tea beverages are susceptible to oxygen degradation, a clarifying filtration method such as lees filtration using filter aids is more suitable in terms of flavor balance than the cross-flow method commonly used in membrane filtration and ultrafiltration.

[0058] Furthermore, diatomaceous earth may be mixed with other filter aids such as silica gel, perlite, and cellulose before use.

[0059] In the filtration process, it is preferable to use a filter aid with a median diameter (D50) of 5 to 30 μm in the cumulative distribution (by volume) of particle sizes after swelling. Using a filter aid with a D50 of 5 μm or more after swelling is preferable because it allows for a richer aftertaste due to the aroma. On the other hand, using a filter aid with a D50 of 30 μm or less is preferable because it allows for drinking without feeling any grittiness on the tongue. From this viewpoint, it is preferable that the filter aid used has a median diameter (D50) of 5 μm or more in the cumulative distribution (by volume) of particle sizes after swelling, more preferably 7 μm or more, and even more preferably 10 μm or more. On the other hand, it is preferable that it is 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. Furthermore, when measuring the cumulative distribution (by volume) of particle size after swelling of the filter aid, the swelling conditions should be such that 10 g of each filter aid is dispersed in 50 times its volume of pure water and immersed for 15 minutes to allow it to swell.

[0060] Furthermore, the filtration aid used preferably has a darcy of 0.03 to 0.25. A darcy of 0.03 or higher is preferable because it allows for an overall sense of concentration due to tea components even after time has passed. On the other hand, a darcy of 0.25 or lower is preferable because it can suppress the generation of sediment over time. From this viewpoint, the filtration aid used preferably has a darcy of 0.03 or higher, more preferably 0.05 or higher, and even more preferably 0.05 or higher. On the other hand, it is preferable that it is 0.25 or lower, more preferably 0.23 or lower, and even more preferably 0.20 or lower. Note that "filtration aid with a darcy of 0.03 to 0.25" means a filtration aid in which the darcy transmittance K is within the range of 0.03 to 0.25. "Darcy transmittance K" is one of the indicators showing the permeability of the filtration aid and can be determined by the water permeation method or the air permeation method. Currently, "darcy" is so commonly used that you can purchase filter aids by specifying this value.

[0061] <Blending Process> In the blending process, water (hard water, soft water, ion-exchanged water, natural water, etc.) is added to dilute the tea extract so that the concentration of tea leaves used is between 8 g / L and 16 g / L. In addition, as needed, one or more of the following ingredients, such as ascorbic acid, sodium ascorbate, baking soda, sugars, dextrin, flavorings, emulsifiers, stabilizers, or other flavoring ingredients, are added to adjust the pH, concentration, and taste. For example, the pH may be adjusted to around 6 and the Brix to around 0.3. One of the features of the manufacturing method of the present invention is that it is possible to increase the concentration of tea polyphenols in the beverage without adding tea polyphenol compositions such as catechin preparations.

[0062] <Sterilization and Container Filling Process> For canned beverages, heat sterilization should be performed by reheating (hot packing) as needed, followed by filling, and then retort sterilization (for example, heating under appropriate pressure (e.g., 1.2 mmHg) at 121°C for 7 minutes). For beverages in plastic bottles, UHT sterilization (holding the mixture at 120-150°C for 1 second to several tens of seconds) should be performed.

[0063] The above manufacturing process, namely the extraction process, coarse filtration process, centrifugal separation process, filtration process, blending process, and sterilization / container filling process for producing a green tea beverage, is merely one example of the present invention and is not limited thereto. For example, the order of the processes can be changed or additional processes can be added.

[0064] <Beverage (Tea Extract)> (Tea Polyphenol Concentration) Green tea beverages after container filling preferably contain 86 mg / 100 mL% or more of tea polyphenols, more preferably 90 mg / 100 mL% or more, more preferably 100 mg / 100 mL% or more, and more preferably 130 mg / 100 mL% or more. On the other hand, from the viewpoint of ease of drinking when consumed as a beverage, it is preferable that the beverage contains 200 mg / 100 mL% or less of tea polyphenols, more preferably 160 mg / 100 mL% or less, more preferably 155 mg / 100 mL% or less, and more preferably 150 mg / 100 mL% or less. In this context, tea polyphenols are a general term for plant components that have multiple phenolic hydroxyl groups in their molecules, mainly consisting 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)), and are commonly known as tannins. The amount of tea polyphenols is the total amount of tannin-like substances containing these eight types of catechins.

[0065] (Transmitted light absorbance value (A)) The tea extract obtained as described above before the filtration step preferably has a transmitted light absorbance value (A) at a wavelength of 660 nm of 0.12 or higher, more preferably 0.13 or higher, and more preferably 0.15 or higher, from the viewpoint of indicating that a tea extract with high levels of tea polyphenols has been obtained. On the other hand, from the viewpoint of reducing the load in the filtration step after extraction, it is preferable that it be 0.22 or lower, more preferably 0.21 or lower, and more preferably 0.19 or lower.

[0066] (Light transmittance) From the viewpoint that green tea beverages after container filling should have a high tea polyphenol content and be golden and transparent, it is preferable that the tea polyphenol content is 86 to 200 mg / 100 mL%, the transmittance at 500 nm is 65% or less, and the ratio of the transmittance at 580 nm to the transmittance at 780 nm (580 nm / 780 nm) is 0.85 or more.

[0067] The tea polyphenol content is the same as described above.

[0068] If the transmittance at 500 nm, which is a blue wavelength, is 65% or less, the liquid will appear darker in color. Therefore, it is preferable that the transmittance at 500 nm be 65% or less, more preferably 62% or less, and even more preferably 60% or less. However, if it is too low, it will be difficult to see that it is transparent, so it is preferable that it be 45% or more, more preferably 51% or more, and even more preferably 56% or more.

[0069] A ratio of the transmittance of the yellow wavelength 580 nm to the transmittance of the red wavelength 780 nm (580 nm / 780 nm) is preferable when it is 0.85 or higher, as this provides a good balance between yellow and red, suppressing the red and resulting in a color closer to gold. From this viewpoint, a ratio of 0.85 or higher is preferable, more preferably 0.87 or higher, and even more preferably 0.90 or higher. However, if the ratio is too high, the liquid color will become lighter, so a ratio of 0.98 or lower is preferable, more preferably 0.97 or lower, and even more preferably 0.95 or lower.

[0070] Furthermore, the usable solids content (Brix) in the beverage (tea extract) obtained as described above is preferably 0.3 or higher, and more preferably 0.5 or higher. On the other hand, it is preferably 2.0 or lower, and more preferably 1.5 or lower.

[0071] It is preferable that the green tea beverage after bottling has a T% (660nm) of 90.0% or higher. A T% (660nm) of 90.0% or higher results in high clarity and a clean taste. From this viewpoint, it is even more preferable that the green tea beverage after bottling has a T% (660nm) of 93.0% or higher. On the other hand, an upper limit of 99.0% or less, and within that, 98.0% or less, can be considered.

[0072] <<Explanation of Terms>> In this specification, when we use the expression "X to Y" (where X and Y are any numbers), unless otherwise specified, it includes the meaning of "greater than or equal to X and less than or equal to Y," as well as the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, when we use the expression "greater than or equal to X" (where X is any number) or "less than or equal to Y" (where Y is any number), it also includes the intention of "preferably greater than X" or "preferably less than Y."

[0073] The present invention will be described in further detail below based on the following examples and comparative examples.

[0074] <Permeability coefficient in the vertical direction of tea leaves> The permeability coefficient k in the vertical direction of each tea leaf and the entire tea leaf layer was calculated using the following formula, based on the amount of tea extract drawn per unit area and unit time and the amount of tea leaves used in the following test, with reference to JIS A 1218 (permeability test of soil): k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml・g / cm) ２ ・s) V: Amount of tea extract (ml) m: Amount of tea leaves (g) S: Water permeability area (cm²) ２ ) t: Water flow time (s)

[0075] <Preliminary Test: Test to obtain the vertical water permeability coefficient of each tea leaf> The water permeability coefficient of each tea leaf was calculated from the above formula based on the values ​​obtained from the following test. Tea leaf separation mesh (area 50 cm) at the bottom. 2 A drip-type cylindrical extractor (φ98 mm) equipped with a valve-equipped outlet pipe (with a draw pipe diameter of φ4 mm) is used, and a mass of 6 g / cm³ per unit area is used within the extractor. ２ To achieve this, 300g of each type of tea leaf was added and piled up to form a tea leaf layer inside the extractor, and the top surface of the tea leaf layer was leveled. After supplying 20 times the amount of hot water as the tea leaves from above the tea leaf layer, the hot water supply was stopped and this state was maintained for 5 minutes. Then, the outlet pipe (φ4mm) valve was opened, and the tea extract was drawn out of the extractor by gravity, and the tea extract was collected until the draw-out flow rate was 0 mL / s. The time from the start to the end of the draw-out (draw-out time) was measured.

[0076] <Preliminary test: Test to obtain the vertical water permeability coefficient of the entire tea leaf layer> The water permeability coefficient of the entire tea leaf layer was calculated from the above formula based on the value obtained from the following test. Tea leaf separation mesh (area 50 cm) at the bottom. 2 A drip-type cylindrical extractor (φ98 mm) equipped with a mesh (80 mesh) and an outlet pipe with a valve (with a draw pipe diameter of φ4 mm) was used. Each type of tea leaf was placed into the extractor and piled up in the same manner as in the test described below, forming a tea leaf layer in the extractor with the second tea leaf layer stacked on top of the first tea leaf layer, and the top surface of the tea leaf layer was leveled. After supplying 20 times the amount of hot water as the tea leaves from above the tea leaf layer, the supply of hot water was stopped and this state was maintained for 5 minutes. Then, the valve of the outlet pipe (φ4 mm) was opened, and the tea extract was drawn out of the extractor by gravity, and the tea extract was collected until the draw flow rate became 0 mL / s. The time from the start to the end of the draw (draw time) was measured.

[0077] <Method for measuring tea polyphenol concentration> The tea polyphenol concentration (mg / 100 mL%, shown as "mg%" in the table) was measured for the diluted tea extract or packaged green tea beverage obtained in the examples and comparative examples using the ferric tartrate method. The amount of tea polyphenols is the amount of tannin-like substances including epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), and gallocatechin gallate (GCg)).

[0078] <Method for measuring transmitted light absorbance at a wavelength of 660 nm> The diluted tea extracts obtained in the examples and comparative examples were shaken well, and a 4.0 mL sample was taken into a standard plastic cell. The absorbance (Abs) (660 nm) was measured using a Shimadzu UV-Vis spectrophotometer UV-1800 and is shown as the transmitted light absorbance value (A).

[0079] <Method for measuring light transmittance> The packaged green tea beverages obtained in the examples and comparative examples were shaken well, and a 4.0 mL sample was taken into a standard plastic cell. The transmittance (T%) at 500 nm, 580 nm, or 780 nm was measured using a Shimadzu UV-Vis spectrophotometer UV-1800.

[0080] <Test 1> The following tea leaves were used as the first and second tea leaves.

[0081] • Pan-fried tea leaves: Kagoshima Prefecture, Yabukita variety, first flush, roasting time 2 minutes, bulk density 0.3 g / cm² ３ 6 g / cm ２ Crude tea with a water permeability coefficient of 71 (tea polyphenol content: 17.0g / 100g, catechin content of 8 types: 14.0g / 100g, amino acid content: 2.5g / 100g, total nitrogen: 4.5g / 100g) - Autumn / Winter Bancha: Shizuoka Prefecture, Yabukita variety, regular steamed tea, steaming time 40 seconds, bulk density 0.25g / cm ３ 6 g / cm ２ Crude tea with a water permeability coefficient of 84 (tea polyphenol content: 15.0g / 100g, catechin content of 8 types: 12.0g / 100g, amino acid content: 0.6g / 100g, total nitrogen: 3.4g / 100g) - Regular steamed tea leaves: Kagoshima Prefecture, Yabukita variety, second flush, steaming time 30 seconds, bulk density 0.33g / cm ３ 6 g / cm ２ Crude tea with a water permeability coefficient of 48 (tea polyphenol content: 21.0g / 100g, catechin content (8 types): 17.0g / 100g, amino acid content: 0.8g / 100g, total nitrogen: 3.6g / 100g)

[0082] (Control) For the control group, the following tea leaves were used as a typical tea leaf used in the production of green tea beverages: • Regular steamed tea leaves, Kagoshima Prefecture, Yabukita variety, second flush, steaming time 30 seconds, bulk density 0.3 g / cm³ ３ 6 g / cm ２ Crude tea with a permeability coefficient of 48 (tea polyphenol content: 13.0 g / 100 g, catechin content: 11.0 g / 100 g, amino acid content: 1.9 g / 100 g, total nitrogen: 4.1 g / 100 g) was used.

[0083] (Extractor) As a drip-type extractor, it has a tea leaf separation mesh (80 mesh, 50 cm² area) at the bottom. 2The extractor used consisted of a cylindrical closed extraction column (inner diameter 98 mm) with a height of 510 mm on a mesh, equipped with a valve-equipped outlet pipe (with a draw pipe diameter of φ4 mm), and an outlet pipe with a valve (with a draw pipe diameter of φ4 mm). Extraction water was supplied from above the tea leaf layer via a shower nozzle, and the tea extract was drawn out from below the extractor through a valve and the draw pipe.

[0084] (Formation of tea leaf layers) First tea leaves, whose vertical permeability coefficient in the total amount of tea leaves is the value shown in the table, are placed into the extractor described above. The first tea leaves are piled up to flatten the top surface of the first tea leaf layer. Then, second tea leaves, whose vertical permeability coefficient in the total amount of tea leaves is the value shown in the table, are placed into the extractor. The second tea leaves are piled up to flatten the top surface of the second tea leaf layer. Thus, the second tea leaf layer is stacked on top of the first tea leaf layer, forming a tea leaf layer with a permeability coefficient equal to the value shown in the table.

[0085] (Extraction) Hot water (temperature 95°C, ion-exchanged water) was supplied to the tea leaf layer from above via a shower nozzle. After supplying 20 times the amount of hot water as the total amount of tea leaves, the supply was stopped and this state was maintained for 5 minutes. Then, the valve on the outlet pipe (φ4 mm) was opened, and the tea extract was drawn out by gravity from the extraction port. The tea extract was collected until the extraction flow rate was 0 mL / s. The time from the start to the end of the extraction (extraction time) was measured and the productivity was evaluated.

[0086] (Productivity Evaluation) 4: Compared to the control, the time required for extraction was reduced by 45% or more. 3: Compared to the control, the time required for extraction was reduced by 35% or more but less than 45%. 2: Compared to the control, the time required for extraction was reduced by 10% or more but less than 35%. 1: Compared to the control, the reduction in the time required for extraction was less than 10% (equivalent to the control).

[0087] <Test 2> Similar to Test 1, tea leaves were added, a tea leaf layer was formed, hot water was supplied, held, and the tea leaves were withdrawn. During this process, the withdrawal time was kept constant, and the tea extract was collected. The amount of collected tea extract was then measured. Subsequently, as with regular bottled green tea beverages, the tea extract was diluted with deionized water to a concentration of 10 g / L using the amount of tea leaves used. The tea polyphenol concentration (mg%) was measured, and a sensory evaluation was performed. The average withdrawal time obtained from the results of Test 1 (485 seconds) was set as the constant time.

[0088] For measuring the tea polyphenol concentration (mg%) and for sensory evaluation, a diluted tea extract was used, obtained by diluting the control tea extract obtained in Test 1 in the same manner as described above.

[0089] (Sensory Evaluation) Ten panelists involved in the manufacture of tea beverages were selected to inspect the diluted tea extracts obtained in the examples and comparative examples. Based on the evaluation criteria, the evaluation with the most votes was adopted.

[0090] 3: Compared to the control, the astringency is more pronounced. 2: Compared to the control, the astringency is slightly more pronounced. 1: Compared to the control, the astringency is the same or weaker.

[0091] (Overall evaluation: Productivity and flavor) ◎: Total score is 7 points or higher, with no ratings of 1 point. 〇: Total score is 5 points or higher and 6 points or lower, with no ratings of 1 point. △: Total score is 4 points or lower, with no ratings of 1 point. ×: Total score is 3 points or lower, or there is a rating of 1 point.

[0092]

[0093] (Discussion) Based on the results of the above examples and comparative examples, as well as the test results conducted by the inventors to date, it was found that by adjusting the type of green tea leaves and the tea season, and by forming a tea leaf layer consisting of first and second tea leaves that take the permeability coefficient into consideration, and by adjusting the permeability coefficient of the entire tea leaf layer to a predetermined range, the extraction time from the extractor can be shortened, and a tea extract with a high concentration of tea polyphenols can be obtained. Regarding the amount of tea polyphenols in the tea extract, if the permeability coefficient of the tea leaf layer consisting of first and second tea leaves is too low, extraction is not completed within the average extraction time, and a sufficient amount of tea polyphenols cannot be obtained, resulting in a quality that does not feel "strong". On the other hand, if the permeability coefficient of the tea leaf layer consisting of first and second tea leaves is too high, the amount of tea polyphenols contained in the first and second tea leaves will be low, or the extraction time in the extractor will be insufficient, resulting in a quality that does not feel "strong".

[0094] <Test 3> The "pan-fried tea leaves" and "regularly steamed tea leaves" used in Example 2 were sieved using sieves of size 8, 12, 20, or 30, as shown in Table 2, to create tea leaves with different shapes for testing. In Example 13, the "pan-fried tea leaves" and "regularly steamed tea leaves" were further roasted using a roasting machine at 175°C for 7.5 minutes under high heat conditions.

[0095] Similar to Experiment 2, tea leaves were added, a tea leaf layer was formed, hot water was supplied, held, and withdrawn. The tea extract was collected until the withdrawal flow rate reached 0 mL / s. The collected tea extract was cooled to 30°C, and the volume and transmitted light absorbance value (A) at a wavelength of 660 nm were measured. The color of the extract was also evaluated, and then it was filtered using a flannel cloth with a mesh size of 50 μm. Next, the filtrate after flannel filtration was subjected to diatomaceous earth filtration using diatomaceous earth to obtain a diatomaceous earth filtered liquid. In this diatomaceous earth filtration, an auxiliary layer (precoat) made of diatomaceous earth was formed on the surface of the filter carrier, and the tea extract was sent to the auxiliary layer. In this case, 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 was used. Next, 450 ppm of ascorbic acid was added to the diatomaceous earth filtration solution, and the pH was adjusted to 6 with baking soda. Then, deionized water was added to dilute the solution so that the concentration of tea leaves used was 14 g / L. UHT sterilization (135°C, 30 seconds) was performed, the solution was cooled in a plate, and the contents were filled into transparent plastic containers (PET bottles) at 85°C to obtain bottled green tea beverage. After that, the caps were sterilized by inverting them for 30 seconds and immediately cooled.

[0096] For Examples 14 and 15, in order to evaluate the astringency of the green tea beverages in containers, extraction, diatomaceous earth filtration, ascorbic acid addition, and pH adjustment were performed in the same manner as in Example 3. For Example 14, ion-exchanged water was added to achieve a tea leaf concentration of 8 g / L, and for Example 15, ion-exchanged water was added to achieve a concentration of 16 g / L. UHT sterilization (135°C, 30 seconds) was performed, the mixture was cooled in a plate, and filled into transparent plastic containers (PET bottles) at 85°C to obtain the green tea beverages in containers. The caps were then inverted for 30 seconds for sterilization and immediately cooled.

[0097] (Evaluation of tea extracts) Ten panelists involved in the manufacture of tea beverages were selected to inspect the diluted tea extracts obtained in the examples and comparative examples. Based on the evaluation criteria, they conducted inspections and, after deliberation, adopted the evaluation with the most votes.

[0098] ◎: The light blue color is clear (reducing the burden of subsequent filtration), and it has a visually rich appearance (it is a strong tea). 〇: The light blue color is clear, but it lacks a sense of richness, or the light blue color has a sense of richness, but it lacks a sense of clarity. △: The light blue color is not clear, or it lacks a sense of richness.

[0099] (Sensory evaluation of packaged green tea beverages) Ten panelists involved in the manufacture of tea beverages were selected to inspect the packaged green tea beverages obtained in the examples and comparative examples. Based on the evaluation criteria, the evaluation with the most votes was adopted.

[0100] ◎: Has a strong astringency, but also possesses the richness and crispness characteristic of sencha. 〇: Has a strong astringency, but lacks the richness or crispness characteristic of sencha. △: Has a strong astringency, but lacks the richness or crispness characteristic of sencha (off-flavors are noticeable). Alternatively, it has the richness and crispness characteristic of sencha, but lacks astringency or is too astringent.

[0101]

[0102] (Discussion) Based on the results of the above examples and comparative examples, as well as the test results conducted by the inventors to date, it has been found that by forming tea leaf layers for the first and second tea leaves, taking into account the permeability coefficient within a suitable range, it is possible to produce a green tea beverage in a golden, transparent container with a high concentration of tea polyphenols.

[0103] Regarding the first batch of tea leaves placed in the extractor, it was found that using tea leaves with a high permeability coefficient resulted in insufficient extraction time due to the short withdrawal time from the extractor. This led to a higher ratio of 580nm transmittance to 780nm transmittance in the resulting bottled green tea beverage, causing it to appear slightly lighter in color. On the other hand, using tea leaves with a low permeability coefficient resulted in a longer retention time of the tea extract in the extractor due to the longer withdrawal time from the extractor. This resulted in a lower ratio of 580nm transmittance to 780nm transmittance in the resulting bottled green tea beverage, causing it to appear reddish. Regarding the second batch of tea leaves placed in the extractor after the first batch, it was found that using tea leaves with a high permeability coefficient resulted in insufficient extraction time due to the short withdrawal time from the extractor. This led to a lower concentration of tea polyphenols in the resulting bottled green tea beverage, resulting in a lack of astringency. On the other hand, when a second type of tea leaf with a low permeability coefficient was used, the withdrawal time from the extractor was longer, resulting in a longer retention time of the tea extract within the extractor. The resulting bottled green tea beverage tended to have a strong astringency but also a noticeable off-flavor.

[0104] Furthermore, it was found that when the first and second tea leaves were roasted over high heat, the permeability coefficient increased, shortening the time required for extraction from the extractor. However, the resulting bottled green tea beverage had a lower ratio of 580 nm transmittance to 780 nm transmittance (580 nm / 780 nm), resulting in a tendency to appear reddish. When a tea extract obtained by forming a tea leaf layer consisting of the first and second tea leaves, taking the permeability coefficient into consideration, was diluted to a drinking level to produce a bottled green tea beverage, it was found that the tea polyphenol concentration at which a bitterness, or so-called "strength," was perceived without being too strong was 86-200 mg / 100 mL. Similarly, when a tea extract was obtained by forming a tea leaf layer consisting of a first tea leaf and a second tea leaf, taking the permeability coefficient into consideration, and then diluting the resulting tea extract to a drinking level to produce a bottled green tea beverage, it was found that the transmittance of the bottled green tea beverage that could be evaluated as golden transparent was 65% or less at 500 nm, particularly 45-64%, and the ratio of the 580 nm transmittance to the 780 nm transmittance (580 nm / 780 nm) was 0.85 or more, particularly 0.85-0.94.

Claims

1. A method for producing a packaged green tea beverage containing a tea extract obtained by drip extraction of tea leaves, comprising: using first and second tea leaves with different permeability coefficients as raw materials; first, the first tea leaves with the higher permeability coefficient are placed into a drip extraction device; then, the second tea leaves with the lower permeability coefficient are placed into the device to form a tea leaf layer in the device, wherein the second tea leaf layer is stacked on top of the first tea leaf layer, and the total permeability coefficient of the tea leaf layer is 70 to 93; supplying an aqueous solvent to the tea leaf layer from above and drawing out the aqueous solvent from below the tea leaf layer to obtain a tea extract; filtering the obtained tea extract to obtain a filtrate; and blending, sterilizing, and filling the filtrate into containers. The permeability coefficient of the entire tea leaf layer described above was determined by placing each of the above tea leaves into a drip-type extractor (pipe diameter: φ4 mm) as described above, with a mass of 6 g / cm³ per unit area. ２ When a tea leaf layer is formed in such a manner, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from the bottom of the tea leaf layer by its own weight, the permeability coefficient k is determined by the following formula: k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml・g / cm ２ ・s) V: Amount of tea extract (mL) m: Amount of tea leaves (g) S: Water permeability area (cm²) 2 ) t: Water flow time (s) 2. A method for producing a packaged green tea beverage according to claim 1, characterized in that the following permeability coefficient of the first tea leaf is 60 or more and 90 or less, and the following permeability coefficient of the second tea leaf is 30 or more and less than 60. The permeability coefficient of each tea leaf is determined by placing each tea leaf into a drip-type extractor (pipe diameter: φ4 mm) and determining that the mass per unit area is 6 g / cm³. ２ When a tea leaf layer is formed in such a manner, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from the bottom of the tea leaf layer by its own weight, the permeability coefficient k is determined by the following formula: k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml・g / cm ２ ・s) V: Amount of tea extract (mL) m: Amount of tea leaves (g) S: Water permeability area (cm²) 2 ) t: Water flow time (s) 3. The method for producing a packaged green tea beverage according to claim 1 or 2, characterized in that the transmitted light absorbance value (A) of the tea extract before filtration at a wavelength of 660 nm is 0.12 to 0.

22.

4. A method for producing a packaged green tea beverage according to claim 1 or 2, wherein the green tea beverage after container filling has a tea polyphenol content of 86 to 200 mg / 100 mL%, a transmittance at 500 nm of 65% or less, and a ratio of the transmittance at 580 nm to the transmittance at 780 nm (580 nm / 780 nm) of 0.85 or more.

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