Manufacturing method for packaged green tea beverages

Abstract

The primary objective is to increase the concentration of tea polyphenols in the beverage, prevent clogging, and shorten the extraction time of the tea extract. [Solution] A method for producing a packaged green tea beverage containing a tea extract obtained by drip extraction of tea leaves, wherein the first tea leaves and the second tea leaves have different permeability coefficients as raw materials, the first tea leaves with a higher permeability coefficient are put into a drip extraction device, the second tea leaves with a lower permeability coefficient are put into the device, and a tea leaf layer is formed in the device, having a structure 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 the aqueous solvent is drawn out from below the tea leaf layer to obtain a tea extract, the obtained tea extract is filtered to obtain a filtrate, the filtrate is blended, sterilized and filled into containers, and so on.

Description

[Technical Field]

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

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

[0003] Traditionally, the method used to prepare packaged green tea beverages involved placing tea leaves and heated extract water into an open-type extraction tank called a kneader, stirring the mixture, and then removing the tea extract. However, the kneading method had limitations in increasing the concentration of tea polyphenols. When attempting to further increase the concentration of tea polyphenols using the kneading method, the tea leaves were finely broken down by agitation, resulting in more off-flavors and reduced clarity. One possible solution to these problems is to use a drip-type brewing device (also known as a "column brewing device" or "column type brewing device"), which is used for brewing coffee, to extract tea.

[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, which is characterized by including the following steps (1) to (3). (1) A step of charging a plurality of teas in layers on a tea holding plate mounted in a column type extractor (2) A step of supplying extraction water from the lower part or the upper part of the extractor and bringing the extraction water into contact with the stacked 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 step of charging tea leaves A into a column type extractor (S B ) A step of supplying extraction water B from the bottom of the extractor (S C ) A step of supplying extraction water C from the upper part of the extractor (S D ) A step of supplying extraction water D from the upper part while extracting the tea extract from the bottom of the extractor

[0007] Patent Document 4 discloses a method for producing a tea extract, in which three or more tea raw materials are charged in layers on a tea holding plate mounted in a column type extractor, extraction water is supplied into the extractor, and the tea extract is discharged. In this method for producing a tea extract, the wetting density of each of the three or more tea raw materials is compared, and any one of the tea raw materials excluding the tea raw materials having the maximum and minimum wetting densities is charged in the uppermost layer. [Prior Art Documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-197920 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-82110 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-57377 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-139655 [Summary of the Invention]

Problems to be Solved by the Invention

[0009] By adopting drip extraction, compared with kneader extraction, there is an advantage that a tea extract with a higher tea polyphenol concentration can be obtained and the production time can be shortened. However, on the other hand, if one tries to increase the tea polyphenol concentration further, it is necessary to charge a larger amount of tea leaves with high extractability of tea polyphenols, for example, tea leaves with a relatively large surface area, into the container. In that case, clogging occurs in the extractor and the extraction time of the tea extract becomes longer, resulting in a problem of deteriorated productivity. In addition, when drip extraction is adopted, it has been reported that the tea extract tends to turn red. Therefore, a first object of the present invention is to provide a method for producing a canned green tea beverage that can increase the tea polyphenol concentration in the beverage and at the same time prevent clogging and shorten the extraction time of the tea extract. A second object is to provide a method for producing a canned green tea beverage that can also prevent the beverage from turning red.

Means for Solving the Problems

[0010] To solve such problems, the present invention proposes the following aspects.

[0011] [1] A first aspect of the present invention is a method for producing a canned green tea beverage containing a tea extract obtained by drip extraction of tea leaves, comprising: using first tea leaves and second tea leaves having different water permeability coefficients as raw materials, putting the first tea leaves with a larger water permeability coefficient into a drip extractor, and then putting the second tea leaves with a smaller water permeability coefficient into the extractor to form a tea leaf layer in the extractor, in which a second tea leaf layer composed of the second tea leaves is laminated on a first tea leaf layer composed of the first tea leaves, and the water permeability coefficient of the entire tea leaf layer is 70 to 93, supplying an aqueous solvent from above to the tea leaf layer and withdrawing the aqueous solvent from below the tea leaf layer to obtain a tea extract, A method for producing a green tea beverage in a container, characterized by filtering the obtained tea extract to obtain a filtrate, and formulating, sterilizing, and filling the filtrate into a container.

[0012] The water permeability coefficient of the entire tea leaf layer 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 charging each of the above tea leaves as described above to form a tea leaf layer with a mass per unit area of 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: Water permeability coefficient in the vertical direction (ml·g / cm 2 ·s) V: Amount of tea extract withdrawn (mL) m: Amount of tea leaves (g) S: Water passing area (cm 2 ) t: Water passing time (s)

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

[0014] The water permeability coefficient of each 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 charging each tea leaf to form a tea leaf layer with a mass per unit area of 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: Water permeability coefficient in the vertical direction (ml·g / cm 2 ·s) V: Amount of tea extract withdrawn (mL) m: Amount of tea leaves (g) S: Water passing area (cm 2 ) t: Water passing time (s)

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

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

[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 a kneader, and also shortens the production time. Furthermore, by introducing the first tea leaves with a higher water permeability coefficient into the extractor, followed by the second tea leaves with a lower water permeability coefficient, 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 stacked on top of it, and the total water permeability coefficient of the tea leaf layer being 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. Furthermore, 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. [Modes for carrying out the invention]

[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 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") involves extracting tea leaves by drip extraction 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 producing a packaged green tea beverage through a blending step and a sterilization and container filling step. However, this manufacturing process is merely one example. The order of each step can be changed, and other steps can be inserted between them.

[0020] <Raw material tea> Green tea leaves, or raw tea leaves, can be any type of tea, regardless of variety, origin, harvesting time, harvesting method, or cultivation method, as long as they are leaves picked from the tea plant (scientific name: Camellia sinensis). It is also possible to use raw tea leaves (including leaves and stems) as raw tea leaves. Furthermore, it is also possible to use crude tea, which has been processed by steaming or roasting these raw tea leaves to stop enzyme activity, as raw tea leaves. In addition, finished tea obtained by applying currently known finishing processes to the crude tea can also be used as raw tea leaves. As for crude tea, any type of tea leaf can be used as raw material, such as sencha, kamairicha, kabusecha, gyokuro, tencha, matcha, bancha, hojicha, steamed tamaryokucha, kamairi tamaryokucha, Ureshino tea, Aoyagi tea, etc. Furthermore, two or more types of these crude teas may be combined, or flavorings may be added during production.

[0021] (First tea leaves and second tea leaves) In the manufacturing method of the present invention, it is preferable to use a first tea leaf and a second tea leaf with different water permeability coefficients, that is, a first tea leaf with a higher water permeability coefficient and a second tea leaf with a lower water permeability coefficient.

[0022] Here, the permeability coefficient of the above tea leaves was determined by placing each type of tea leaf into a drip-type extractor (with a pipe diameter of φ4 mm) and piling it up, with a mass of 6 g / cm³ per unit area. 2The permeability coefficient k is obtained by the following formula when a test is conducted in which 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. k = (V × m) / (t × S) k: Perimeter of water permeability in the vertical direction (ml·g / cm²) 2 ·s) V: Amount of tea extract drawn (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0023] The permeability coefficient of tea leaves can be adjusted by factors such as the amount of tea leaves, the type of tea (first flush, autumn / winter bancha, etc.), the shape (degree of twisting), the size, and the degree of roasting (pan-frying / steaming, crude tea / finished tea, heating temperature during finishing).

[0024] The first tea leaf is preferably one that does not clog easily, that is, one with a high water permeability coefficient. Therefore, the water permeability coefficient of the first tea leaf is preferably between 60 and 90, and more preferably between 65 and 70. On the other hand, the second tea leaf may be a tea leaf that easily clogs, that is, a tea leaf with a low permeability coefficient. Therefore, it is preferable that the permeability coefficient of the second tea leaf be 30 or more and less than 60, and more preferably 35 or more, and even more preferably 40 or more.

[0025] The difference in the permeability coefficient between the first and second tea leaves should preferably be greater than 0, and more preferably 5 or higher, and even more preferably 10 or higher, because it is desirable for the second tea leaf to have a lower permeability coefficient but still allow for easier extraction of tea polyphenols. On the other hand, if the permeability coefficient of the second tea leaf is too low, the tea extract will clog in the second tea leaf portion, making extraction impossible. Therefore, it is preferable that the permeability coefficient be 60 or lower, more preferably 50 or lower, and even more preferably 40 or lower.

[0026] The first type of tea leaf must have a relatively high water permeability coefficient. From this perspective, the first type of tea leaf suitable from a roasting standpoint is so-called "hard" tea leaves such as pan-fried tea, roasted tea, and finished tea. For example, tea leaves that have fully developed buds, tea leaves that have been kneaded less during the crude tea manufacturing process, and gricha are suitable. In terms of tea season, autumn / winter bancha (coarse tea) is preferred among ordinary steamed tea leaves. On the other hand, for pan-fired tea, first flush, second flush, third flush, and autumn / winter bancha can be used. From the viewpoint of sufficiently extracting tea polyphenols into the extract, first flush or second flush tea is more preferable.

[0027] Furthermore, the "pan-fried tea" mentioned above refers to tea that has been subjected to a roasting process instead of steaming in the process of killing the green enzymes in the tea leaves. The "Guri-cha" mentioned above refers to a type of tea that, unlike the long, slender shape of sencha, is processed into a rough, curly shape. The "roasted tea" mentioned above is tea that has been finished by applying high heat to crude tea until it acquires a roasted aroma. Compared to crude tea and regular sencha, it has less moisture and is harder.

[0028] Regarding the size of the tea leaves, those that remain on the surface when sifted through a No. 30 sieve are preferable, and those that remain on the surface when sifted through a No. 20 sieve are even preferable. The preferred tea polyphenol content of the first type of tea leaves is 5-25g / 100g, more preferably 8-25g / 100g, and particularly preferably 10-25g / 100g. 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% or more by mass or 70% or less by mass, and particularly preferably 30% or more by mass or 60% or less by mass. 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. Furthermore, 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 type of tea leaf is preferably one that has 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 perspective, the second tea leaf material should preferably be a so-called "soft" tea leaf raw material such as regular steamed tea, deep-steamed tea, or extra-steamed tea. From the perspective of softness, for example, "mill buds" that are picked early, and tea leaves that are kneaded extensively during the crude tea manufacturing process, such as tea leaves that have been kneaded under increased pressure during the rolling process, are preferable. From the viewpoint of ensuring that tea polyphenols are sufficiently extracted into the extract, it is preferable to use first or second flush tea leaves. Furthermore, it is preferable to use unrefined tea rather than finished tea.

[0030] The "regular steamed tea" mentioned above refers to tea that has undergone a "steaming" process in the "killing green" stage, which stops the enzyme activity in the tea leaves. It has the characteristic of having softer leaves than "pan-fried tea" and is more likely to absorb moisture and expand. The above-mentioned "deep-steamed tea" and "extremely steamed tea" are teas that have been subjected to a long steaming process during the raw tea processing stage, which stops the activity of enzymes in the tea leaves. Because the normal steaming process is broken down, the raw tea has the characteristic of being finer in shape than "pan-fried tea" or "regularly steamed tea."

[0031] As mentioned above, the second layer of tea leaves is preferably made of finely ground tea leaves, as it has a relatively large surface area. From this perspective, it is preferable to sift the second layer of tea leaves using a No. 4 sieve and remove the tea leaves on the sieve, and in particular, it is preferable to sift them using a No. 8 sieve and remove the tea leaves on the sieve. The second type of tea leaf is preferably a so-called "fine" tea leaf raw material, such as crushed tea or powdered tea.

[0032] The second type of tea leaves contains a tea polyphenol content of 10-30g / 100g, more preferably 12-30g / 100g, and particularly preferably 15-30g / 100g. 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. Furthermore, the total nitrogen content 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 developed leaves, for example, leaves with a hardening degree of 50-70, or leaves that have been kneaded less during the crude tea manufacturing process, such as gyokucha. On the other hand, the second type of tea leaves can be described as tea leaves that have been kneaded extensively during the crude tea manufacturing process, such as tea leaves that have been kneaded under increased pressure during the rolling process, or so-called "fine" tea leaves such as crushed tea or powdered tea, such as tea leaves that are picked early and are soft, such as 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, removing the leaves below a sieve of size 30 or 20, i.e., removing fine tea leaves, can increase the permeability coefficients of the first and second tea leaves. On the other hand, removing the leaves above a sieve of size 4 or 8, i.e., removing larger tea leaves, can decrease the permeability coefficients of the first and second tea leaves. In this invention, it is desirable to adjust the water 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 tea leaves below sieve No. 30, and more preferably to remove the tea leaves below sieve No. 20. On the other hand, it is desirable to extract tea polyphenols more efficiently from the second tea leaves than from the first tea leaves. Therefore, when adjusting the size of the second tea leaves by sieving, it is preferable to remove the tea leaves above sieve No. 4, and more preferably to remove the tea leaves above sieve No. 8.

[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 amount is 0.21 g / cm³ or more, and more preferably 0.21 g / cm³. 3 Among them, 0.22 g / cm³ 3 It is even more preferable if the above conditions are met. On the other hand, the second type of tea leaf bulk density, 0.22 g / cm³, increases the surface area of ​​the tea leaves and enhances the extractability of tea polyphenols. 3 Preferably, the amount is 0.24 g / cm³ or more, and more preferably 0.24 g / cm³. 3Among 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 3 Preferably, the following, and especially 0.6 g / cm³ 3 The following is more preferable, and among them, 0.5 g / cm³ is preferable. 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 first introduce and deposit the first tea leaves with a higher water permeability coefficient into the extractor, then introduce and deposit the second tea leaves with a lower water permeability coefficient into the extractor, 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. An aqueous solvent is supplied to the tea leaf layer from above, and the aqueous solvent is drawn out from below the tea leaf layer to obtain a tea extract. In this case, 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 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 prolong the extraction time. In particular, placing large quantities of so-called "soft" tea leaves, such as regular steamed or deep-steamed tea leaves, is prone to clogging. Therefore, by first introducing the first tea leaves with a higher water permeability coefficient into the extractor, and then introducing the second tea leaves with a lower water permeability coefficient, a tea leaf layer is formed in the extractor, with the second tea leaf layer consisting of the second tea leaves stacked on top of the first tea leaf layer consisting of the first tea leaves, and the water permeability coefficient of the entire tea leaf layer is within a predetermined range, for example, 70 to 93. By extracting after this, a tea extract with a high concentration of tea polyphenols can be produced 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 the kneader method, the drip method allows for the extraction of tea-derived components with less water, and also enables the use of a larger amount of tea leaves at once. This shortens production time and allows for 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, green tea beverages tend to oxidize and change color from golden to red as the manufacturing time increases. By using the drip method, the extraction time can be shortened, which has the advantage of making it easier to obtain a green tea beverage that is rich in tea polyphenols and has a clear golden color. However, simply employing a drip-style extraction method is not sufficient to 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-type extraction column; an extraction means for extracting the tea liquid from below the extractor; and a tea leaf holding plate for holding tea leaves inside. The means of supplying extraction water to the tea leaf layer in the extractor can be any method that supplies the extraction water from above the tea leaf layer, such as via a shower nozzle. However, it is not limited to a shower nozzle. The means for extracting the tea extract can be any method that discharges the tea extract from the extraction pipe via a valve. The tea extract may be extracted by gravity, or it may be extracted using a power source 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, with 40 mesh or more or 120 mesh or less being more preferable, and 60 mesh or more or 100 mesh or less being even more preferable, from the viewpoint of substantially separating the prepared tea from the tea extract.

[0040] (Formation of the tea leaf layer) The first tea leaves, which have 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, which have 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 a tea leaf layer within the extractor.

[0041] It is preferable to pile the first batch of tea leaves, level the surface of the tea so that the height is uniform, then add the second batch of tea leaves, pile them up, and level the surface of the tea 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, the method is not limited to this.

[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 be 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 be 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, in order to shorten the extraction time from the viewpoint of quality and manufacturing efficiency. On the other hand, from the viewpoint of increasing the tea polyphenol concentration, it is preferable that it be 93 or less, and more preferably 90 or less, and even more preferably 88 or less. The permeability coefficient of the above tea leaf layer can be adjusted by the permeability coefficients and quantities 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 (with a pipe diameter of φ4mm) as described above, and the mass per unit area was 6g / cm³. 2 The permeability coefficient k is obtained by the following formula when a test is conducted in which 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. It should be noted 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 (drawing 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) k: Perimeter of water permeability in the vertical direction (ml·g / cm²) 2 ·s) V: Amount of tea extract drawn (mL) m: Tea leaf amount (g) S: Water flow area (cm 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 used for extraction, 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 among these, extraction at temperatures of 72°C or higher or 99°C or lower is preferred, among these, 75°C or higher or 98°C or lower is preferred, and among these, 78°C or higher or 97°C or lower is even more preferred.

[0049] (Drawing speed of tea extract) The rate at which the tea extract is drawn out depends, for example, on the tea leaf separation mesh at the bottom (area 50cm²). 2 When using a drip-type cylindrical extractor (φ98mm) equipped with 80 mesh and extracting from a φ4mm diameter extraction pipe, from the viewpoint of production efficiency (extraction time), a extraction rate of 550 mL / min or more is preferable, more preferably 600 mL / min or more, and even more preferably 700 mL / min or more. While a faster extraction speed of the tea extract is preferable, it is considered difficult to achieve a rate of 5000 mL / min or more. The extraction speed of the tea extract can be adjusted by controlling 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, the opening of the valve on the outlet pipe, and the holding time between the primary and secondary showers.

[0050] <Rough 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 centrifuged if necessary. Centrifugal separation can be performed under conditions such as a flow rate of 200-500 L / h and a rotation speed of 5000-20000 rpm. By changing the flow rate, rotation speed, and centrifugal sedimentation area (Σ), the clarity (T%) of the final bottled green tea beverage can be adjusted. When centrifuging, it is preferable to cool the tea extract to about 5-40°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 centrifugal separation before the filtration process can reduce the burden on the filtration process. For example, increasing the permeate flow rate and decreasing the permeate pressure can shorten the filtration time. However, since fine particles can also be removed during the filtration process, it is possible to omit centrifugal separation if the filtration process is performed, although this will slightly increase the burden on the material.

[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 filter aid. In this case, it is preferable to use mineral-derived filtration aids, considering their effect on the flavor of green tea beverages. Examples of mineral-derived filter aids include diatomaceous earth derived from fossil minerals and perlite derived from volcanic rock. Among these, diatomaceous earth is preferred in terms of 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 microscopic 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 diatomaceous earth that has been refined by calcination.

[0057] Diatomaceous earth filtration is a type of slag filtration that uses diatomaceous earth as a filter aid. As a method of diatomaceous earth filtration, a pre-coat layer made of diatomaceous earth is formed on the surface of the filter carrier, and the diatomaceous earth filter agent is injected into the raw solution (tea extract as an unfiltered liquid) as needed (body feed), while the raw solution (tea extract as an unfiltered liquid) is sent to the pre-coat layer. Here, "pre-coating" refers to the process of dispersing an auxiliary agent in a clear liquid before the filtration operation, circulating it, and forming a layer of the auxiliary agent several millimeters thick on the surface of the filter media (e.g., 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 media, 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 filtration aid with a D50 of 5 μm or more after swelling is preferable because it allows for a richer flavor due to the aftertaste's aroma. On the other hand, using a filtration 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, the filter aid used is preferably one in which the median diameter (D50) in the cumulative distribution (by volume) of particle size after swelling is 5 μm or more, more preferably 7 μm or more, and more preferably 10 μm or more. On the other hand, it is preferably 30 μm or less, more preferably 25 μm or less, and more preferably 20 μm or less. When measuring the cumulative distribution (by volume) of particle size after swelling of the filter aid, the swelling conditions should be as follows: disperse 10g of each filter aid in 50 times its volume of pure water and immerse it for 15 minutes to allow it to swell.

[0060] Furthermore, it is preferable that the filtration aid used has a darcy content of 0.03 to 0.25. A darcy filter aid 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 value of 0.25 or lower is preferable because it can suppress the formation of sediment over time. From this viewpoint, the filtration aid used is preferably such that the darcy content is 0.03 or higher, more preferably 0.05 or higher, and even more preferably 0.20 or higher. On the other hand, it is preferably 0.25 or lower, more preferably 0.23 or lower, and even more preferably 0.20 or lower. Furthermore, "a filter aid with a darcy value of 0.03 to 0.25" refers to a filter aid whose darcy transmittance K is within the range of 0.03 to 0.25. "Darcy transmittance K" is one of the indicators of the permeability of a filter aid and can be determined by the water permeation method or the air permeation method. Currently, "darcy" is so commonly used that filter aids can be purchased by specifying this value.

[0061] <Blending Process> In the blending process, water (hard water, soft water, deionized water, natural water, etc.) is added to dilute the tea extract so that the concentration of tea leaves used is between 8g / L and 16g / L. Additionally, ascorbic acid, sodium ascorbate, baking soda, sugars, dextrin, flavorings, emulsifiers, stabilizers, or other flavoring ingredients, or a combination of two or more of these, are added as needed to primarily 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 present invention is that it can increase the concentration of tea polyphenols in beverages without adding tea polyphenol compositions such as catechin preparations.

[0062] <Sterilization / container filling process> For heat sterilization, canned beverages should be reheated (hot-packed) as needed before filling, followed by retort sterilization (for example, heat sterilization at 121°C for 7 minutes under appropriate pressure (e.g., 1.2 mmHg)). For beverages in plastic bottles, UHT sterilization (holding the mixture at 120-150°C for 1 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 consumption as a beverage, it is preferable that the tea contains tea polyphenols at a ratio of 200 mg / 100 mL% or less, and more preferably at a ratio of 160 mg / 100 mL% or less, 155 mg / 100 mL% or less, and even more preferably at 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 what 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) of 0.12 or higher at a wavelength of 660 nm, more preferably 0.13 or higher, and even 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 even more preferably 0.19 or lower.

[0066] (Light transmittance) From the viewpoint of preferring that the green tea beverage after container filling has a high tea polyphenol content and is golden and transparent, it is preferable that the tea polyphenol content is 86-200 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 a blue wavelength of 500 nm 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 not appear 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 580nm to the transmittance of the red wavelength 780nm (580nm / 780nm) is 0.85 or higher, which is preferable because it indicates a good balance between yellow and red, suppressing red and resulting in a color closer to gold. From this perspective, the ratio (580nm / 780nm) is preferably 0.85 or higher, more preferably 0.87 or higher, and even more preferably 0.90 or higher. However, if it is too high, the liquid color will become lighter, so it is preferably 0.98 or lower, 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 being filled into containers, 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 perspective, it is even more preferable that the green tea beverage after container filling has a T% (660nm) of 93.0% or higher. On the other hand, the upper limit can be assumed to be 99.0% or less, and more specifically, 98.0% or less.

[0072] <<Explanation of terms>> In this specification, when "X~Y" (where X and Y are any numbers) is used, unless otherwise specified, it means "greater than or equal to X and less than or equal to Y," and also includes the meanings of "preferably greater than X" or "preferably less than Y." Furthermore, when we use expressions like "greater than or equal to X" (where X is any number) or "less than or equal to Y" (where Y is any number), we also imply that "greater than X is preferable" or "less than Y is preferable." [Examples]

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

[0074] <Permeability coefficient of tea leaves in the vertical direction> The vertical permeability coefficient k for 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 tests, with reference to JIS A 1218 (Soil Permeability Test). k = (V × m) / (t × S) k: Perimeter of water permeability in the vertical direction (ml·g / cm²) 2 ·s) V: Amount of tea extract drawn (ml) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0075] <Preliminary testing: Tests to determine the vertical water permeability coefficient of each tea leaf> The permeability coefficient of each tea leaf was calculated using the above formula based on the values ​​obtained from the following tests. Tea leaf separation mesh at the bottom (area 50cm 2 A drip-type cylindrical extractor (φ98mm) equipped with a valve-equipped outlet pipe (with a draw pipe diameter of φ4mm) is used, and a mass of 6g / 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 aforementioned 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. The tea extract was collected until the draw-out flow rate became 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 permeability coefficient of the entire tea leaf layer was calculated using the above formula based on the values ​​obtained from the following tests. Tea leaf separation mesh at the bottom (area 50cm 2 A drip-type cylindrical extractor (φ98mm) equipped with a mesh (80 mesh) and an outlet pipe with a valve (with a draw pipe diameter of φ4mm) 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 where the second tea leaf layer was 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 aforementioned 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. The tea extract was collected until the draw-out flow rate became 0 mL / s. The time from the start to the end of the draw-out (draw-out time) was measured.

[0077] <Method for measuring tea polyphenol concentration> The concentration of tea polyphenols (mg / 100mL%, indicated as "mg%" in the table) was measured in the diluted tea extracts or packaged green tea beverages obtained in the examples and comparative examples using the ferric tartrate method. The amount of tea polyphenols refers to 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 containerized 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 0.3g / cm³ 3 , 6g / 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 Tea: Produced in Shizuoka Prefecture, Yabukita variety, regular steamed tea, steaming time 40 seconds, bulk density 0.25 g / cm³ 3 , 6g / cm 2 Crude tea with a water permeability coefficient of 84 (tea polyphenol content: 15.0g / 100g, catechin content (8 types): 12.0g / 100g, amino acid content: 0.6g / 100g, total nitrogen: 3.4g / 100g) • Standard steamed tea leaves: Kagoshima Prefecture, Yabukita variety, second flush, steaming time 30 seconds, bulk density 0.33 g / cm³ 3 , 6g / 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 typical tea leaves used in the production of green tea beverages. • Regular steamed tea leaves, Kagoshima Prefecture, Yabukita variety, second flush, steaming time 30 seconds, bulk density 0.3g / cm³ 3 , 6g / cm 2 Crude tea with a permeability coefficient of 48 (tea polyphenol content: 13.0g / 100g, catechin content: 11.0g / 100g, amino acid content: 1.9g / 100g, total nitrogen: 4.1g / 100g) was used.

[0083] (extractor) As a drip-type brewing device, it has a tea leaf separation mesh (80 mesh, 50cm² area) at the bottom. 2 The 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 extraction water supply from above the tea leaf layer via a shower nozzle, and the tea extract liquid was drawn out from below the extractor through a valve and the draw pipe.

[0084] (Formation of the tea leaf layer) In the extraction apparatus described above, a first layer of tea leaves, whose vertical water permeability coefficient in the total amount of tea leaves is the value shown in the table, was placed and piled up to flatten the top surface of the first tea leaf layer. Then, a second layer of tea leaves, whose vertical water permeability coefficient in the total amount of tea leaves is the value shown in the table, was placed and piled up to flatten the top surface of the second tea leaf layer. Thus, the second tea leaf layer was stacked on top of the first tea leaf layer, forming a tea leaf layer with a water 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 outlet pipe (φ4mm) valve 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 became 0 mL / s. The time from the start to the end of the extraction (extraction time) was measured, and productivity was evaluated.

[0086] (Productivity evaluation) 4. Compared to the control group, the time required for extraction was reduced by more than 45%. 3. Compared to the control group, the time required for extraction was reduced by 35% to less than 45%. 2. Compared to the control group, the time required for extraction was reduced by 10% to less than 35%. 1. Compared to the control, the reduction in withdrawal time was less than 10% (similar to the control).

[0087] <Exam 2> Similar to Experiment 1, tea leaves were added, a tea leaf layer was formed, hot water was supplied, held, and the tea was 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 typical packaged 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 then measured, and a sensory evaluation was performed. As a fixed time, the average extraction time (485 seconds) obtained from the results of Test 1 was set.

[0088] As a control for measuring tea polyphenol concentration (mg%) and 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 their evaluation criteria, the panelists conducted tests, and the evaluation with the most votes was adopted.

[0090] 3: Compared to Control, it has a stronger bitter taste. 2: Compared to Control, it has a slightly stronger bitter taste. 1: Compared to Control, the bitterness feels similar or weaker.

[0091] (Overall evaluation: productivity and flavor) ◎: The total score is 7 points or higher, and there are no scores of 1 point. ○: The total score is between 5 and 6 points, and there are no scores of 1 point. △: The total score is 4 points or less, and there are no evaluations of 1 point. ×: The total score is 3 points or less, or there is a score of 1 point.

[0092] [Table 1]

[0093] (Consideration) 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 adjusting the type of green tea leaves and the tea-ripening period, and by forming a tea leaf layer consisting of a first tea leaf and a second tea leaf, taking into account the water permeability coefficient, and adjusting the water 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 the first and second tea leaves was too low, extraction was not completed within the average extraction time, resulting in insufficient tea polyphenols and a quality that could be perceived as "strong." On the other hand, if the permeability coefficient of the tea leaf layer consisting of the first and second tea leaves was too high, the amount of tea polyphenols contained in the first and second tea leaves would be low, or the extraction time in the extractor would be insufficient, resulting in insufficient tea polyphenols and a quality that could be perceived as "strong."

[0094] <Exam 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, which were then used for the test. 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 its 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 through 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 this 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 then 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 then filled into transparent plastic containers (PET bottles) at 85°C to obtain the green tea beverages in containers. After that, the caps were inverted for 30 seconds for sterilization and immediately cooled.

[0097] (Evaluation of tea extract) 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 their evaluation criteria, the panelists conducted tests, and the evaluation with the most votes was adopted.

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

[0099] (Sensory evaluation of bottled green tea beverages) For the packaged green tea beverages obtained in the examples and comparative examples, ten panelists involved in the manufacture of tea beverages were selected. They conducted inspections based on each evaluation, and the evaluation with the most votes was adopted after deliberation.

[0100] ◎: It has a strong astringency, yet possesses the rich flavor and crisp finish characteristic of sencha green tea. ○: It has a strong astringency, but as a sencha, it lacks a bit of body or a slightly poor finish. △: Has a strong astringency but lacks the richness and crispness of sencha, or lacks a clean finish (off-flavors are noticeable). Alternatively, it has the richness and crispness of sencha, but lacks astringency or is too astringent.

[0101] [Table 2]

[0102] (Consideration) 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 consideration 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 when using tea leaves with a high water permeability coefficient, the extraction time was insufficient due to the short withdrawal time from the extractor. As a result, the ratio of 580nm to 780nm transmittance in the resulting bottled green tea beverage was high, and the color of the beverage tended to appear slightly lighter. On the other hand, when using tea leaves with a low water permeability coefficient, the withdrawal time from the extractor was longer, resulting in a longer retention time of the tea extract in the extractor. As a result, the ratio of 580nm to 780nm transmittance in the resulting bottled green tea beverage was low, and the beverage tended to appear reddish. Regarding the second tea leaves added to the extractor after the first tea leaves, it was found that using second tea leaves with a high water permeability coefficient resulted in insufficient extraction time due to the short withdrawal time from the extractor, and the resulting bottled green tea beverage tended to have a low concentration of tea polyphenols and lack astringency. On the other hand, using second tea leaves with a low water permeability coefficient resulted in a longer withdrawal time from the extractor, which increased the retention time of the tea extract within the extractor, and 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 water permeability coefficient increased, shortening the time required for extraction from the extractor. However, the resulting bottled green tea beverage had a lower ratio of 580nm transmittance to 780nm transmittance (580nm / 780nm), resulting in a tendency to appear reddish. When a tea extract obtained by forming a tea leaf layer consisting of a first and second tea leaf, taking the hydropermeability coefficient into consideration, was diluted to a drinking level, and a bottled green tea beverage was manufactured, it was found that the tea polyphenol concentration at which a bitterness, or so-called "strength," is perceived without being too strong is 86-200 mg / 100 mL. Similarly, when a tea extract obtained by forming a tea leaf layer consisting of a first and second tea leaf, taking the hydropermeability coefficient into consideration, was diluted to a drinking level, and a bottled green tea beverage was manufactured, 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 580 nm to 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, Using two tea leaves, one with a first permeability coefficient and the other with a second permeability coefficient, as raw materials, the first tea leaves with the higher permeability coefficient are placed into a drip-type extractor, and then the second tea leaves with the lower permeability coefficient are placed into the extractor, thereby forming a tea leaf layer in the extractor 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 between 70 and 93. A tea extract is obtained by supplying an aqueous solvent to the tea leaf layer from above and withdrawing the aqueous solvent from below the tea leaf layer. A method for producing a packaged green tea beverage, characterized by filtering the obtained tea extract to obtain a filtrate, and then mixing, 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 The permeability coefficient k is obtained by the following formula when a test is conducted in which 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. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml・g / cm²) ２ ・s) V: Amount of tea extract drawn (mL) m: Tea leaf amount (g) S: Water flow area (cm) 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 was determined by placing each tea leaf into a drip-type extractor (with a pipe diameter of φ4 mm) and finding that the mass per unit area was 6 g / cm³. ２ The permeability coefficient k is obtained by the following formula when a test is conducted in which 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. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml・g / cm²) ２ ・s) V: Amount of tea extract drawn (mL) m: Tea leaf amount (g) S: Water flow area (cm) 2 ) t: Water flow time (s)

3. A 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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