JP5111096B2 - Production method of tea extract - Google Patents

Description

  The present invention relates to a method for producing a tea extract.

  The effects of catechins have been reported to be a cholesterol elevation inhibitory action, an α-amylase activity inhibitory action, and the like. In order to express such physiological effects, it is effective to ingest a large amount of catechins more simply. As a method of blending a high concentration of catechins into a beverage, for example, a method of adding catechins in a dissolved state to a beverage using a concentrate of a green tea extract or the like is known, but depending on the method of extracting green tea An unpleasant nasty taste such as egg taste may occur.

  Numerous proposals have been made as a technique for reducing such a taste, for example, a method of adding a high-sweetness sweetener derived from spirantol or a plant extract or plant essential oil containing spirantol (see Patent Document 1), A method of adding a taste improving agent comprising vicenin-2 (see Patent Document 2), a method of adding a carbohydrate derivative of α, α′-trehalose (see Patent Document 3), and the like have been reported.

JP 2006-223104 A JP 2006-238828 A International Publication No. 2004/060077 Pamphlet

However, the addition of a small amount of these sweeteners or the like to a tea extract containing non-polymer catechins cannot sufficiently reduce the unpleasant taste and tends to impair the original flavor and aroma of tea. Moreover, when refine | purifying the tea extract after sweetener addition, the added sweetener may have a bad influence on refinement | purification. Thus, there is a limit to means for reducing the taste by using a sweetener or the like.
Therefore, the objective of this invention is providing the manufacturing method of the tea extract by which the taste was suppressed, and the tea extract obtained by this manufacturing method.

  The present inventor has obtained knowledge that different flavors can be felt depending on the turbid state of the tea extract obtained from tea and the conditions of the heat treatment. The present inventor has examined in further detail, and by separating the tea extract obtained from tea into solid and liquid under a predetermined condition and further heat-treating the obtained tea extract under a predetermined condition, It was found that a tea extract with a suppressed taste was obtained.

In the present invention, the first tea extract obtained from tea is subjected to solid-liquid separation so that the turbidity when the concentration of non-polymer catechins is 1% by mass is 200 NTU or less. To obtain a second tea extract having a concentration of 0.2 to 5% by mass and a non-polymer catechin concentration in the solid content of 15 to 80% by mass, and then subjecting the second tea extract to temperature The present invention provides a method for producing a tea extract, which is heat-treated at 95 to 140 ° C. and an F value of 0.05 to 40 (Z = 10).
The present invention also provides a tea extract obtained by the production method described above.

  According to the production method of the present invention, a poorly water-soluble component such as oxalic acid, protein, fiber, and lipid is selectively and efficiently removed, so that not only the taste but also the bitter taste and the heated odor are suppressed. Can be easily produced. In addition, this tea extract is suppressed in the taste, bitterness and unpleasant odor, and contains a high concentration of non-polymer catechins, so that a large amount of catechins can be easily consumed. It is useful as a raw material for producing beverages.

  In the present invention, non-polymer catechins include non-epimeric catechins such as catechin, gallocatechin, catechin gallate, and gallocatechin gallate, and epimeric catechins such as epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. The concentration of non-polymer catechins is defined based on the total amount of the above eight types. Further, the non-epimeric ratio is a value of 100 fraction of the mass sum of the four types of non-epicatechins relative to the mass sum of the eight types of non-polymer catechins.

  The non-polymer catechin gallate body in the present invention is a general term that includes four types of catechin gallate, gallocatechin gallate, epicatechin gallate and epigallocatechin gallate. It is the value of 100 percent of the mass sum of the four non-polymer catechin gallate bodies relative to the mass sum of the combined catechins.

  The first tea extract used in the present invention is extracted from tea and contains at least one non-polymer catechin. Examples of the tea used for extraction include non-fermented tea, semi-fermented tea, and fermented tea depending on the degree of fermentation. Non-fermented tea includes Camellia, such as C.I. sinensis and C.I. Examples include green teas such as sencha, bancha, gyokuro, tencha, and kettle roasted tea, which are made from tea leaves obtained from assamica, yabukita or hybrids thereof. Semi-fermented tea or fermented tea includes teas, oolong teas, black teas made from the genus Camellia, such as C. sinensis and C. assamica, tea obtained from hybrids, or semi-fermented or fermented tea. Tea etc. are mentioned. Among these, non-fermented tea having a high content of non-polymer catechins is preferable.

  In the present invention, not only tea leaves but also stem tea, stick tea, and bud tea can be used. Examples of stem tea include tea stem parts that are usually used as stem tea, and stick tea parts that are the stems and stem parts of tea leaves that are usually used as stick tea. Furthermore, examples of bud tea include soft bud portions that have not yet become leaves and are usually used as bud tea.

  Extraction from tea can be performed by a known method such as kneader extraction, stirring extraction (batch extraction), countercurrent extraction (drip extraction), column extraction, etc., using water as an extraction solvent. At the time of extraction, an organic acid such as ascorbic acid or a sodium salt thereof or a salt thereof may be added to water in advance. Moreover, you may use together the method of extracting in so-called non-oxidative atmosphere, ventilating inert gas, such as boiling deaeration and nitrogen gas, and removing dissolved oxygen.

  Moreover, what diluted or melt | dissolved the concentrate of the tea extract in water as a 1st tea extract may be used, and also the extract extracted from tea and the diluted solution or solution of the said concentrate are used together May be. Here, the concentrate of tea extract is a concentrate obtained by concentrating an extract extracted from tea leaves with hot water or a water-soluble organic solvent. For example, JP-A-59-219384, JP-A-4-20589. No. 5, 260-907, JP-A-5-306279, and the like. Further, as a concentrate of a commercially available tea extract, a purified catechin preparation such as “Polyphenone” manufactured by Tokyo Food Techno Co., “Theafuran” manufactured by ITO EN, or “Sunphenon” manufactured by Taiyo Kagaku may be used.

  In the production method of the present invention, first, the first tea extract is subjected to solid-liquid separation. As a result, the solid content and the water-soluble part are separated. In the present invention, when the second tea extract that is the water-soluble part is an aqueous solution having a non-polymer catechin concentration of 1% by mass. The first tea extract is subjected to solid-liquid separation so that the turbidity of the aqueous solution is 200 NTU or less. The turbidity of the aqueous solution is 200 NTU or less, preferably 150 NTU or less, particularly preferably 100 NTU or less. If the turbidity is 200 NTU or less, the taste can be reduced. The lower limit of turbidity is preferably 0.01 NTU or more, particularly 0.1 NTU or more, from the viewpoint of the stability of the tea extract. Here, turbidity refers to diluting the second tea extract obtained by solid-liquid separation with ion-exchanged water so that the concentration of non-polymer catechins in the tea extract is 1% by mass, It means what was measured using a turbidimeter in a wavelength range of 850 nm and a 90 ° transmission scattering comparison method.

  Membrane treatment, filtration, centrifugation, etc. can be adopted as solid-liquid separation means for obtaining a predetermined turbidity, but membrane treatment, particularly microfiltration (MF), more reliably removes poorly water-soluble components. And it is preferable at the point which is easy to adjust to desired turbidity. Further, before the membrane treatment, it is preferable to separate the solid content and the water-soluble portion by filtration and / or centrifugation because the filtration speed is improved in the subsequent membrane treatment and the production efficiency is excellent.

  The conditions for solid-liquid separation are, for example, as follows. The temperature for the film treatment is preferably 5 to 70 ° C, particularly preferably 10 to 60 ° C. The pressure is, for example, preferably 30 to 400 kPa, more preferably 50 to 400 kPa, and particularly preferably 50 to 350 kPa. The membrane pore diameter is preferably 0.1 to 0.8 μm, more preferably 0.1 to 0.45 μm, and particularly preferably 0.1 to 0.25 μm in that it can be easily adjusted to a predetermined turbidity. Examples of the method for measuring the membrane pore diameter include general measurement methods using a mercury intrusion method, a bubble point test, a bacterial filtration method, and the like, but it is preferable to use values obtained by the bubble point test.

  Examples of the membrane that can be used in the present invention include hydrocarbon-based, fluorinated hydrocarbon-based, or sulfone-based polymer membranes and ceramic membranes. Examples of the hydrocarbon polymer film include a polyolefin polymer film, and specific examples include polyethylene and polypropylene. Examples of the fluorinated hydrocarbon polymer film include a fluorinated polyolefin polymer film, and specific examples include polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF). Examples of the sulfone polymer film include polysulfone (PSU), polyethersulfone (PES), and the like. Examples of the ceramic film include “Cefilt” manufactured by NGK and “SCUMASIV” manufactured by Nippon Pole. Among these, a ceramic membrane is preferable in that the pore distribution is sharp and the filtration accuracy is excellent. Examples of the membrane include flat membranes, spiral membranes, hollow fiber membranes, monolith type membranes, etc. Among them, continuous processing types such as spiral membranes, hollow fiber membranes and monolith type membranes can be processed efficiently. This is preferable.

  Centrifugation is preferably performed using a general apparatus such as a separation plate type, a cylindrical type, or a decanter type. As the centrifugation conditions, the temperature is preferably 5 to 70 ° C, particularly 10 to 40 ° C. For example, in the case of a separation plate type, the number of rotations and time are 4000 to 10000 rpm, further 5000 to 10000 rpm, particularly 6000 to 10000 rpm, 0.2 to 30 minutes, further 0.2 to 20 minutes, and particularly 0.2 to 15. Minutes are preferred.

  Filtration is usually performed in combination with other solid-liquid separation means for the purpose of rough filtration. For example, filter separation using a filter made of metal such as filter paper or stainless steel can be employed. The mesh size of the metal filter is preferably 18 to 300 mesh.

  The second tea extract obtained by solid-liquid separation has a non-polymer catechin concentration of 0.2 to 5% by mass and a non-polymer catechin concentration in the solid content of 15 to 80% by mass. However, in order to obtain a tea extract having such properties, if necessary, a part of the water may be removed from the second extract and concentrated. The concentration of the non-polymer catechins is preferably 0.2 to 4% by mass, particularly preferably 0.2 to 3% by mass, from the viewpoint of preventing increase in coloring due to heat treatment. In addition, the concentration of non-polymer catechins in the solid content is preferably 20 to 70% by mass, and particularly preferably 25 to 50% by mass, from the viewpoint of reducing taste by heat treatment.

Next, the second tea extract is heated. The heat treatment conditions are a temperature of 95 to 140 ° C. and an F value of 0.05 to 40 (Z = 10), but the heating temperature is preferably 98 to 135 ° C., particularly preferably 100 to 130 ° C. The F value is preferably 0.07 to 35, and particularly preferably 0.07 to 30. If the heating temperature and the F value are less than the lower limit, even if the heat treatment is performed, the taste is not reduced.
Here, in this specification, the F value is used as an index for displaying the heat sterilization effect, and is a value (unit: minutes) converted to the sterilization effect at a heating temperature of 121.1 ° C. The value calculated from the equation.

  In the formula, Z represents a constant 10, t represents a heating temperature (° C.), and sec represents a heating time (second).

In the present invention, the second tea extract or the tea extract obtained by heat treatment may be treated with an enzyme having tannase activity in order to reduce bitterness and astringency. In this case, the tannase treatment of the second tea extract is preferable to the tannase treatment of the tea extract obtained by the heat treatment.
The tannase used here should just have the activity which hydrolyzes non-polymer catechin gallate body. Specifically, tannase obtained by culturing tannase-producing bacteria such as Aspergillus, Penicillium, Rhizopus and the like can be used. Of these, those derived from Aspergillus oryzae are particularly preferred.
In the tannase treatment, it is preferable to add powdered or solution tannase to the second tea extract so as to have a concentration of 25 to 500 Unit / L, particularly 50 to 150 Unit / L. The amount of tannase added is 0.1 Unit or more, preferably 0.2 Unit or more, per 1 g of tea extract having a non-polymer catechin concentration of 0.67% by mass. Here, 1Unit is defined as the amount of enzyme that hydrolyzes 1 micromole of an ester bond contained in tannic acid in water at 30 ° C.

  After adding the enzyme having tannase activity, hold the second tea extract at 20 ° C. to 50 ° C., particularly 20 ° C. to 40 ° C. until the gallate content in the non-polymer catechins reaches 1 to 60% by mass. It is preferable to do. The gallate content in the non-polymer catechins is preferably adjusted to 3 to 55% by mass, particularly 5 to 50% by mass. Thereafter, the temperature is raised as quickly as possible to deactivate the tannase to stop the reaction, and at the same time, heat treatment is performed at the F value. Thereby, since the process of reducing the bitterness and astringency by the treatment of tannase and the process of reducing the taste by heat treatment are carried out at the same time, a tea extract having a good color tone with a further suppressed taste is obtained. As a result, the manufacturing process can be simplified and the operation cost can be reduced. In addition, the tannase inactivation treatment can prevent a subsequent decrease in the gallate body ratio, and a tea extract having the desired gallate body ratio can be easily obtained.

  Next, the tea extract obtained by the heat treatment can be concentrated or dried as necessary to increase the concentration into a form such as a solid, powder, or granulated product. Examples of the concentration increasing method by concentration or drying include vacuum concentration, reverse osmosis membrane concentration, spray drying, and freeze drying, and these can be performed in combination. Among these, vacuum concentration or spray drying is preferable from the viewpoint of low heat history, and reverse osmosis membrane concentration is preferable from the viewpoint of energy saving because of low heat history. As an efficient method of increasing the concentration, for example, first, primary concentration is performed to a solid content concentration of 30 to 60% by mass by vacuum concentration or reverse osmosis membrane concentration, and then powderization is performed by spray drying or freeze drying depending on the application. The method of doing is mentioned.

  According to the above process, not only the taste but also the bitterness and the heated odor are suppressed, and a highly concentrated non-polymer catechins-containing tea extract having excellent stability at the time of blending the beverage is obtained.

  The tea extract of the present invention can be further dispersed in a mixed solution of an organic solvent and water, and then contact-treated with activated carbon and acidic clay or activated clay. As a result, a high-quality, low-caffeine content tea extract having excellent stability over time while containing a high concentration of non-polymer catechins can be obtained.

  The content ratio of the organic solvent to water is preferably 60/40 to 97/3, more preferably 60/40 to 95/5, particularly 85/15 to 95/5, for extraction of non-polymer catechins. It is preferable in terms of efficiency, purification of tea extract, long-term drinking ability, and the like.

  Examples of the organic solvent include alcohols such as ethanol and methanol, ketones such as acetone, esters such as ethyl acetate, and the like. Among these, hydrophilic organic solvents such as alcohols and ketones are preferable, and alcohols, particularly ethanol are preferable in consideration of use in foods. Examples of water include ion exchange water, tap water, and natural water. The organic solvent and water may be mixed or mixed with the tea extract that has been filtered separately, but it is preferable that the organic solvent and water be mixed with the tea extract after forming a mixed solution.

  The amount of tea extract used (in terms of dry mass) is 10 to 40 parts by mass, more preferably 10 to 30 parts by mass, and particularly 15 to 30 parts by mass with respect to 100 parts by mass of the mixed solution of the organic solvent and water. This is preferable in terms of efficient processing.

  It is more preferable to provide an aging time of about 10 to 180 minutes after the addition of the mixed solution of the organic solvent and water. These treatments can be carried out at 10 to 60 ° C., preferably 10 to 50 ° C., more preferably 10 to 40 ° C.

  Activated carbon is added in an amount of 0.5 to 8 parts by mass, particularly 0.5 to 3 parts by mass with respect to 100 parts by mass of a mixed solution of an organic solvent and water. Is preferable. Moreover, the mixing ratio of the activated carbon and the acid clay or the activated clay is preferably 1 to 10 with respect to the activated carbon 1 by mass ratio, and is preferably activated carbon: acid clay or activated clay = 1: 1 to 1: 6. .

  The caffeine in the tea extract thus produced can be 4 to 200, more preferably 15 to 200, particularly 30 to 200 in terms of the mass ratio of non-polymer catechins / caffeine.

  The tea extract of the present invention maintains a high concentration of non-polymerized catechins in spite of suppression of taste, bitterness, and heated odor. Therefore, the tea extract of the present invention is useful as a raw material for container-packed beverages, particularly tea beverages such as green tea, oolong tea, blended tea, black tea, barley tea, non-tea beverages such as sports beverages, isotonic beverages, and near water. Useful as.

  In the packaged beverage, non-polymer catechins are preferably contained in an amount of 0.03 to 1.0% by mass, more preferably 0.04 to 0.5% by mass, and still more preferably 0.06 to 0.4% by mass, more preferably 0.08 to 0.3% by mass, and particularly preferably 0.1 to 0.3% by mass. When the content of the non-polymer catechins is within this range, a large amount of the non-polymer catechins can be easily ingested, which is preferable from the viewpoint of the color tone immediately after the beverage preparation.

  The packaged beverage may contain sodium ions and / or potassium ions. Beverages containing these ions are useful as beverage forms such as sports drinks and isotonic drinks.

  A sweetener can be used in the packaged beverage for the purpose of improving the taste. Examples of the sweetener include artificial sweeteners, carbohydrates, and glycerol (for example, glycerin).

  It is desirable for the stability of the catechins to adjust the pH of the packaged beverage to 2 to 7, preferably 2 to 6.5, more preferably 3 to 4.5.

  The container-packed beverage is preferable because it is easy to drink when a bitter and astringent taste inhibitor is blended. As the bitter and astringent taste inhibitor, cyclodextrin is preferred. As the cyclodextrin, α-, β-, γ-cyclodextrin and branched cyclodextrin can be used. For packaged beverages, antioxidants, fragrances, various esters, organic acids, organic acid salts, inorganic acids, inorganic acid salts, inorganic salts, pigments, emulsifiers, preservatives, seasonings, acidulants, gums, emulsifiers Additives such as oil, vitamins, amino acids, fruit juice extracts, vegetable extracts, nectar extracts, pH adjusters, quality stabilizers and the like can be used alone or in combination.

  Containers used for packaged beverages are usually molded containers (so-called PET bottles) mainly composed of polyethylene terephthalate, metal cans, paper containers combined with metal foil or plastic film, bottles, etc. Can be provided. The term “packaged beverage” as used herein means a beverage that can be drunk without dilution.

  Container-packed beverages are manufactured under the sterilization conditions stipulated in the Food Sanitation Law if they can be sterilized by heating after filling them into containers such as metal cans. For those that cannot be used, a sterilization condition equivalent to the above, for example, a method of sterilizing at a high temperature and short time in a plate heat exchanger or the like and then cooling to a certain temperature and filling the container is adopted. Moreover, you may mix | blend another component with the filled container under aseptic conditions. Furthermore, after sterilization by heating under acidic conditions, the pH can be returned to neutrality under aseptic conditions, or after sterilization by heating under neutral conditions, the pH can be returned to acidic conditions under aseptic conditions.

(Measurement of non-polymer catechins)
A tea extract or tea extract is diluted with ion-exchanged water, filtered through a membrane filter (0.8 μm), and then diluted with distilled water, and a sample packed in an octadecyl group-introduced liquid chromatograph L-column TM ODS Using a high-performance liquid chromatograph (model SCL-10AVP) manufactured by Shimadzu Corporation equipped with (4.6 mmφ × 250 mm: manufactured by Chemical Substance Evaluation Research Organization), the measurement was performed by a gradient method at a column temperature of 35 ° C. The mobile phase A solution was a distilled aqueous solution containing 0.1 mol / L of acetic acid, the B solution was an acetonitrile solution containing 0.1 mol / L of acetic acid, the sample injection amount was 20 μL, and the UV detector wavelength was 280 nm. .

(Measurement of turbidity)
The second tea extract obtained by solid-liquid separation is diluted with ion-exchanged water so that the concentration of non-polymer catechins is 1% by mass, and this is used as a sample for a turbidimeter (Turbidimeter / TN-100 EUTECH INSTRUMENTS) was used, and measurement was performed by a 90 ° transmission / scattering comparison method with a wavelength range of 850 nm.

(Evaluation of flavor)
Each tea extract was diluted with ion-exchanged water so that the non-polymer catechin concentration was 175 mg / 100 mL, and the flavor (egg taste, bitter taste, heated odor) was evaluated according to the following criteria on five male monitors. did. The results are shown in Tables 1, 2, and 3.

(1) Evaluation standard of taste taste A: Difficult to feel B: Difficult to feel C: Feel somewhat D: Feel

(2) Evaluation criteria for bitterness A: Difficult to feel B: Slightly difficult to feel C: Slightly feel D: Feel

(3) Evaluation Criteria for Heating Odor A: Difficult to Feel B: Difficult to Feel C: Slightly Feel D: Feel

Example 1
(1) 100 g of green tea leaves (from Kenya, large leaf type) were stirred in 3 kg of hot water at 50 ° C. for 15 minutes to perform batch extraction to obtain a first tea extract. Next, the first tea extract is roughly filtered through a 70-mesh and 200-mesh wire mesh, cooled to 25 ° C., and then a batch-type centrifuge (Hitachi) is used to remove the fine powder in the first tea extract. Centrifugation was performed at 25 ° C. and 8000 rpm for 10 minutes using a high-speed cooling centrifuge CR22G manufactured by Koki Co., Ltd. to obtain 2300 g of a second tea extract.
(2) 100 g of the obtained second tea extract was immersed in a warm bath set at 100 ° C. for 9 minutes, and after cooling, the obtained tea extract was freeze-dried (Tokyo Rika Kikai Co., Ltd., FD -81) and lyophilized to obtain a powdery tea extract.

Example 2
A tea extract was obtained in the same manner as in Example 1 except that 100 g of green tea leaves (produced in Kenya, large leaf type) were extracted in hot water at 80 ° C. to obtain a first tea extract.

Example 3
A tea extract was obtained in the same manner as in Example 1, except that 100 g of green tea leaves (produced in Kenya, large leaf type) were extracted in hot water at 90 ° C. to obtain the first tea extract.

Example 4
(1) By the same method as in Example 2, 100 g of green tea leaves (produced from Kenya, large leaf type) was stirred in 3 kg of hot water at 80 ° C. for 15 minutes to perform batch extraction to obtain a first tea extract. It was. Next, after roughly filtering with a 70 mesh and 200 mesh wire mesh and cooling to 25 ° C., the first tea extract was filtered at 25 ° C. with a 0.2 μm ceramic filter (Cefilt, manufactured by NGK Co., Ltd.) with an average filtration pressure of 0. Microfiltration (MF treatment) at 1 MPa was performed to obtain a second extract.
(2) After heat-treating 100 g of the obtained 2nd extract by the method similar to Example 1, it lyophilized | freeze-dried and the powdery tea extract was obtained.

Example 5
A tea extract was obtained in the same manner as in Example 4 except that 100 g of green tea leaves (produced in Kenya, large leaf type) were extracted in hot water at 75 ° C. to obtain the first tea extract.

Example 6
(1) As in Example 5, batch extraction was performed by stirring in hot water at 75 ° C. for 15 minutes to obtain a first tea extract. Next, the first tea extract was roughly filtered with a 70 mesh and 200 mesh wire mesh and cooled to 25 ° C., and then the first tea extract was filtered with a 0.2 μm ceramic filter (Cefilt, manufactured by NGK Corporation). Microfiltration (MF treatment) was performed at 25 ° C. and an average filtration pressure of 0.1 MPa to obtain a second tea extract.
(2) The obtained second extract is continuously heated at a flow rate of 110 ml / min (temperature increase; oil bath, inner diameter 2.27 mmφ × 10 m, holding part; inner diameter 10.7 mmφ × 2 m) At 124 ° C. and a residence time of 1.5 min, and continuously cooled to 25 ° C. Thereafter, the obtained tea extract was freeze-dried with a freeze dryer to obtain a powdery tea extract.

Example 7
A tea extract was obtained by the same method as in Example 6 except that the heat treatment conditions were 130 ° C. and 1.5 min.

Example 8
A tea extract was obtained in the same manner as in Example 6 except that the heat treatment conditions were 133 ° C. and 1.5 min.

Example 9
A tea extract was obtained in the same manner as in Example 6 except that the heat treatment conditions were 138 ° C., 0.5 min, holding part; inner diameter 10.7 mmφ × 0.67 m.

Example 10
The second tea extract obtained in Example 4 (1) was kept at a temperature of 25 ° C., and tannase (Kikkoman Corp., tannase KTFH, 500 U / g) was 120 ppm with respect to the second tea extract. (60 Unit / L) was added and held for 100 minutes, and then heat treatment was performed under the heat treatment conditions described in Example 6. Thereafter, the obtained tea extract was freeze-dried with a freeze dryer to obtain a powdery tea extract.

Comparative Example 1
A tea extract was obtained in the same manner as in Example 2 except that 100 g of the second tea extract was lyophilized with a freeze dryer without heat treatment.

Comparative Example 2
(1) 100 g of green tea leaves (from Kenya, large leaf type) were stirred in 3 kg of hot water at 80 ° C. for 15 minutes to perform batch extraction to obtain a first tea extract. Next, the first tea extract was coarsely filtered through a 70 mesh and 200 mesh wire net and cooled to 25 ° C. to obtain a second tea extract.
(2) 100 g of the obtained second tea extract is immersed in a warm bath set at 100 ° C. for 9 minutes, and after cooling, the obtained tea extract is freeze-dried with a freeze dryer, A tea extract was obtained.

Comparative Example 3
A tea extract was obtained in the same manner as in Example 2 except that the centrifugation conditions were 3000 rpm and 10 minutes.

Comparative Example 4
A tea extract was obtained by the same method as in Example 5 except that the heat treatment conditions were 90 ° C. and 30 minutes.

Comparative Example 5
A tea extract was obtained in the same manner as in Example 5 except that the heat treatment conditions were 100 ° C. and 3 minutes.

Comparative Example 6
A tea extract was obtained in the same manner as in Example 6 except that the heat treatment conditions were 133 ° C. and 3 minutes.

Comparative Example 7
The second tea extract obtained in Example 4 (1) was kept at a temperature of 25 ° C., and tannase (Kikkoman Corp., tannase KTFH, 500 U / g) was 120 ppm with respect to the second tea extract. (60 U / L) was added and held for 100 minutes, then heated to 80 ° C. and held for 3 minutes to inactivate the enzyme. Thereafter, the obtained tea extract was freeze-dried with a freeze dryer to obtain a powdery tea extract.

Table 1 shows the analysis results of the tea extracts obtained in Examples 1 to 4 and Comparative Examples 1 to 3 and the evaluation results on the flavor.
The analysis results of the tea extracts obtained in Examples 5 to 9 and Comparative Examples 4 to 6 and the evaluation results on the flavor are shown in Table 2.
Table 3 shows the analysis results of the tea extract obtained in Example 10 and Comparative Example 7 and the evaluation results on the flavor.
Moreover, the relationship between a heating condition and flavor is shown in FIG. 1 about the tea extract obtained in Examples 5-9 and Comparative Examples 4-6.

  From the results shown in Tables 1 to 3, the tea extracts obtained in Examples 1 to 10 all had a good flavor, with a suppressed taste, bitterness and heated odor. On the other hand, the tea extracts obtained in Comparative Examples 1 to 5 and 7 had a strong taste, and the tea extract obtained in Comparative Example 6 showed a strong heated odor and bitterness. Further, FIG. 1 demonstrates the significance of heat treatment at a temperature of 95 to 140 ° C. and an F value of 0.05 to 40 (Z = 10).

It is a figure which shows the relationship between a heating condition and flavor.

Claims (3)

The first tea extract obtained from tea is treated with a microfiltration membrane so that the turbidity when the non-polymer catechin concentration is 1% by mass is 100 NTU or less, and non-polymer catechins are obtained. A second tea extract having a concentration of 0.2 to 3 % by mass and a non-polymer catechin concentration in the solid content of 25 to 50 % by mass is obtained, and then the second tea extract is heated to a temperature of 100. to 140 ° C., and heat treated at F value 0.07 ~ 30 (Z = 10) , then concentrated and dried, the preparation of the tea extract. Precise pore size of the membrane is 0.1 to 0.8 [mu] m, method as described in claim 1.   The production according to claim 1 or 2, wherein the second tea extract is treated with an enzyme having tannase activity to adjust the gallate content in the non-polymer catechins to 1 to 60% by mass, and then heat-treated. Law.

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