JP6568756B2 - Production method of tea extract - Google Patents

Description

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

  Tannins including catechins are natural polyphenols contained in tea leaves and the like and have been reported to have various physiological activities. In order to express such a physiological effect, it is necessary to ingest a large amount of polyphenols more easily, and there is a beverage as a means for easily ingesting it as a lifestyle habit. As a technique for blending polyphenols in a beverage at a high concentration, for example, a method of adding a polyphenol in a dissolved state to a beverage using a tea extract or the like is known, but it contains abundant polyphenols and has a good flavor. There is a need for tea extracts.

  Conventionally, as a technique for producing catechins with high extraction efficiency and having a good flavor, for example, green tea leaves are extracted with water of less than 10 ° C., and the extraction residue is extracted with warm water of 50 ° C. or higher. (Patent Document 1), a method of extracting tea leaves with hot water of 55 to 80 ° C., extracting tea husk above the temperature and in a short time, and then mixing the two extracts (Patent Document) 2) A method is proposed in which tea leaves are extracted with warm water, tea leaves are extracted at a temperature lower than that of the warm water and the amount of warm water is controlled to be constant, and then both extracts are mixed (Patent Document 3). Has been.

JP 2003-219799 A JP 2008-131932 A JP 2010-252697 A

In the method of producing a tea extract by extraction from tea leaves, it is difficult to sufficiently recover the tea extract impregnated in the tea husk when industrially separating the tea husk from the tea extract. The original flavor of tea tends to be insufficient. Therefore, in the above-mentioned prior art, two-stage extraction and washing of the tea husk after extraction are adopted, but the tannin recovery rate is improved, but the flavor is easily impaired.
The subject of this invention is providing the manufacturing method of the tea extract which collect | recovers tannin efficiently and is excellent in flavor.

  The inventor obtains a tea extract from tea leaves in an extractor having an upper opening, and then tilts the extractor in a predetermined direction at a constant speed, and discharges the tea extract including tea husks from the opening of the extractor. Thus, it has been found that the separation between the tea husk and the tea extract is improved, and tannin can be efficiently recovered without requiring tea husk washing, and a tea extract having an excellent flavor can be obtained.

That is, the present invention includes a first step of obtaining tea extract by mixing tea leaves and water in an extraction device having an opening on the upper side,
The perforated plate including a large number of holes from which the tea extraction liquid containing tea husk is tilted through the opening at an angular velocity of 0.0073 to 0.06 rad / s so that the opening forms an inclination angle with respect to the horizontal direction. A method for producing a tea extract, comprising: a second step of discharging to a screen comprising: a third step of separating a tea husk and a tea extract on the screen.

  According to the present invention, the separability between the tea husk and the tea extract is improved, and it is possible to industrially advantageously produce a tea extract that efficiently recovers tannin and does not require washing of the tea husk and is excellent in flavor. it can.

  The manufacturing method of the tea extract of this invention includes a 1st process, a 2nd process, and a 3rd process. Hereinafter, each step will be described in detail.

<First step>
The first step is a step of obtaining a tea extract by mixing tea leaves and water in an extraction device having an opening upward.

(Extraction device)
The extraction device has an opening vertically upward. The shape of the opening is not particularly limited as long as the contents can be taken in and out from the opening, and may be, for example, a circle, an ellipse, or a rectangle. Further, the opening may be provided with a detachable lid.
The capacity of the extraction device is not uniform depending on the extraction scale, but is usually 1.0 to 4,000 L, preferably 50 to 3,000 L, and the extraction device may have a stirring means. Further, the extraction apparatus may have a structure that can be heated or cooled (for example, an electric heater or a jacket through which hot water, steam, or cold water can flow) in order to keep the extraction temperature constant.
Examples of the extraction device include a kneader extractor, a column extractor, and a multi-function extractor. Among these, a kneader extractor is preferable from the viewpoint of extraction efficiency.

(tea leaf)
The tea leaves include, for example, Camellia genus, for example, C. sinensis var. Sinensis (including Yabutaki species), C. sinensis var. Tea leaves are classified into non-fermented tea, semi-fermented tea, and fermented tea depending on the processing method, and one or more of these can be appropriately selected and used.

  Examples of non-fermented tea leaves include green tea leaves such as sencha, bancha, strawberry tea, kettle tea, stem tea, stick tea, and bud tea. In addition, examples of the semi-fermented tea leaves include oolong tea leaves such as iron kannon, color species, golden katsura, and wushuiwa tea. Furthermore, examples of fermented tea leaves include black tea leaves such as Darjeeling, Assam and Sri Lanka. These can be used alone or in combination of two or more. Among these, non-fermented tea leaves are preferable and green tea leaves are more preferable from the viewpoint of tannin content. Here, “tannin” in the present specification is a concept including non-polymer catechins, esters thereof (for example, gallic acid esters) and condensates thereof.

(water)
As water, for example, tap water, distilled water, ion-exchanged water, natural water and the like can be appropriately selected and used. Among these, ion exchange water is preferable.
The temperature of water is usually 50 ° C. or higher, but from the viewpoint of extraction efficiency, 55 ° C. or higher is preferable, 60 ° C. or higher is more preferable, 65 ° C. or higher is further preferable, and 95 ° C. from the viewpoint of easy temperature control. The following is preferable, 90 ° C. or lower is more preferable, and 85 ° C. or lower is further preferable. The temperature range of water is preferably 50 to 95 ° C, more preferably 55 to 90 ° C, still more preferably 60 to 90 ° C, and still more preferably 65 to 85 ° C.

  The amount of water used can be appropriately selected depending on the extraction scale, but it is preferably 5 times by mass or more, more preferably 10 times by mass or more, still more preferably 20 times by mass or more, and 80 times by mass with respect to tea leaves. The following is preferable, 60 mass times or less is more preferable, and 40 mass times or less is still more preferable. As a range of the usage-amount of water, Preferably it is 5-80 mass times with respect to tea leaves, More preferably, it is 10-60 mass times, More preferably, it is 20-40 mass times.

(mixture)
A tea extract is prepared by putting tea leaves and water into an extraction device and mixing them.
The mixing order of tea leaves and water is not particularly limited, and both may be charged and mixed in an arbitrary order, or both may be charged and mixed simultaneously. Moreover, you may stir when mixing a tea leaf and water.
The mixing time is not uniform depending on the extraction scale and can be selected as appropriate. However, from the viewpoint of extraction efficiency, it is preferably 2 minutes or more, more preferably 3 minutes or more, further preferably 4 minutes or more, and 30 minutes. The following is preferable, 20 minutes or less is more preferable, and 10 minutes or less is still more preferable. The mixing time is preferably 2 to 30 minutes, more preferably 3 to 20 minutes, and still more preferably 4 to 10 minutes.

<Second step>
In the second step, the extraction device is tilted at an angular velocity of 0.0073 to 0.06 rad / s so that the opening forms an inclination angle with respect to the horizontal direction, and the tea extract containing tea husk is removed from the opening with a large number of holes. It is the process of discharging to the screen which consists of a perforated board.

(Tilt)
In the second step, the extraction device is first inclined so that the opening forms an inclination angle with respect to the horizontal direction, but the extraction device is inclined so that the normal opening faces vertically downward.
The extraction device may be tilted manually, but in order to keep the tilting speed constant, a drive motor may be attached to the extraction device and electrically controlled.
The extraction device is preferably tilted so as to form an inclination angle of 1 / 2πrad or more, and more preferably 1.75 rad or more, from the viewpoint of the liquid collection rate. Further, the tilt angle is preferably 4 rad or less from the viewpoint of apparatus constraints, and particularly preferably π rad or less, and more preferably 2.6 rad or less from the viewpoint of suppressing discharge of the tea husk onto the screen.

  The tilting speed of the extractor is an angular speed of 0.0073 to 0.06 rad / s, and is preferably 0.008 rad / s or more from the viewpoint of separation efficiency (liquid collection rate) and tannin recovery rate, and 0.01 rad / s. The above is more preferable, 0.03 rad / s or less is preferable, and 0.025 rad / s or less is more preferable. The range of the angular velocity is preferably 0.008 to 0.03 rad / s, more preferably 0.01 to 0.025 rad / s. Here, “angular velocity” in this specification indicates the tilting speed of the extracting device in radians per second (rad / s), and represents the angle at which the extracting device tilts per unit time (sec).

(Discharge)
From the opening of the inclined extraction device, the tea extract containing the tea leaves in the extraction device is discharged onto a screen installed vertically below.
The screen is a perforated plate having a large number of holes. Examples of the shape of the screen include a flat plate shape, a conical shape, and a pyramid shape, but a flat plate shape is preferable from the viewpoint of separation efficiency. Further, the planar shape of the screen may be, for example, a circle, an ellipse, or a square. The material of the screen is preferably made of metal such as stainless steel from the viewpoint of corrosion prevention and strength. The shape of the hole may be any of a circle, an ellipse, and a rectangle, and can be appropriately selected.
The opening diameter of the screen is not particularly limited as long as the opening is smaller than the tea shell, but when the hole shape is circular, the inner diameter is usually 1.5 to 2.5 mm. From the viewpoint of separation efficiency, the aperture ratio of the screen is preferably 20 to 50%, more preferably 25 to 50%, and still more preferably 30 to 50%. Here, in this specification, “aperture ratio” is defined as the ratio (percentage) of the area of the hole to the total area (including the area of the hole) of the screen.
As the screen, for example, a metal filter having a mesh size of preferably 16 to 100 mesh, more preferably 18 to 100 mesh, and still more preferably 20 to 80 mesh can be used.

<Third step>
The third step is a step of separating the tea husk and the tea extract on the screen. The tea leaves are deposited on the screen, and the tea extract that has passed through the holes in the screen is collected in a tank disposed below the screen.
The separation time is not uniform depending on the extraction scale, and can be appropriately selected. However, from the viewpoint of production efficiency, it is preferably 1 minute or more, more preferably 2 minutes or more, and preferably 10 minutes or less, and 8 minutes or less. Is more preferable, and 5 minutes or less is still more preferable. The range of the separation time is preferably 1 to 10 minutes, more preferably 1 to 8 minutes, and further preferably 2 to 5 minutes.
In the present invention, it is not always necessary to wash the tea leaves on the screen. In the case of washing the tea husk, it is preferably performed in a short time. For example, the washing time is within 4 seconds. In addition, the above-mentioned water is usually used for washing the tea leaves.

  Moreover, you may solid-liquid-separate the collect | recovered tea extract after a 3rd process as needed. As solid-liquid separation, solid-liquid separation means usually used in the food industry can be employed, and examples thereof include centrifugation, liquid (hydro) cyclone, membrane filtration and the like. Solid-liquid separation can also be performed in combination of two or more.

Centrifugation can be performed using a general apparatus such as a separation plate type, a cylindrical type, or a decanter type. Centrifugation conditions can be appropriately selected. For example, the temperature is preferably 5 to 70 ° C., more preferably 10 to 40 ° C., and the rotation speed and time are preferably 4000, for example, in the case of a separation plate type. 10000 rpm, more preferably 5000 to 10000 rpm, still more preferably 6000 to 10000 rpm, preferably 0.2 to 30 minutes, more preferably 0.2 to 20 minutes, still more preferably 0.2 to 15 minutes. .
A hydrocyclone is a device that separates and separates particles in a liquid using centrifugal force instead of gravity. Separation conditions are appropriately set if, for example, a spiral water flow is generated in the apparatus, and impurities in the tea extract can be settled and separated by a specific gravity difference using a force (centrifugal force) acting in the direction perpendicular to the rotation axis. be able to. Further, the tea extract may be passed through the liquid cyclone a plurality of times.
When performing membrane filtration, as membrane filtration conditions, for example, the temperature is preferably 5 to 70 ° C, more preferably 10 to 40 ° C. The membrane pore diameter is preferably 0.1 to 10 μm, more preferably 0.1 to 5 μm, and further preferably 0.1 to 2 μm from the viewpoint of filtration efficiency and insoluble matter separation. 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 a value obtained by a bubble point test. Examples of the material of the membrane used for membrane filtration include a polymer membrane, a ceramic membrane, and a stainless membrane.

  In this way, it is possible to produce a tea extract that recovers tannin with a high yield and is excellent in flavor. The recovery rate of tannin is preferably 40% by mass or more, more preferably 45% by mass or more, and further preferably 50% by mass or more. The “tannin recovery rate” is analyzed by the method described in the examples below.

  Examples of the tea extract include various forms such as liquid, slurry, semi-solid, and solid. The tea extract may be used as it is, but can also be concentrated. Examples of the concentration method include vacuum concentration, reverse osmosis membrane concentration, and the like. Moreover, when a powder is desirable as a product form of the tea extract, it can be dried and pulverized by, for example, spray drying or freeze drying, and can be performed in combination with concentration.

The tea extract of this invention can be used conveniently for preparation of food-drinks, especially a drink.
The blending amount of the tea extract in the beverage can be appropriately selected. For example, the Brix of the beverage at 20 ° C. is preferably 0.40 ± 0.1%, more preferably 0.30 ±. A tea extract can be mix | blended so that it may become 0.1%. In this case, the content of tannin in the beverage is preferably 0.5 to 0.9 mass%, more preferably 0.6 to 0.8 mass%. Moreover, when preparing a drink, it is also possible to dilute with water, another tea extract, etc. Examples of water include the same as described above.

  The beverage of the present invention may be a tea beverage or a non-tea beverage. Examples of tea beverages include green tea beverages, oolong tea beverages, and black tea beverages. Non-tea beverages include, for example, non-alcoholic beverages such as fruit juice, vegetable juice, sports beverages, isotonic beverages, enhanced water, bottled water, near water, coffee beverages, nutritional drinks and beauty drinks, beer And alcoholic beverages such as wine, sake, plum wine, happoshu, whiskey, brandy, shochu, rum, gin, and liqueurs. In addition, the form of a drink is not specifically limited, As long as it is a form which is easy to ingest, any of liquid form, gel form, slurry form, etc. may be sufficient.

  Furthermore, the beverage of the present invention includes flavors, vitamins, minerals, antioxidants, esters, pigments, emulsifiers, preservatives, seasonings, sweeteners, acidulants, fruit juice extracts, vegetable extracts, nectar extracts, and quality stabilizers. Such additives can be blended alone or in combination of two or more. The blending amount of these additives can be appropriately set within a range not impairing the object of the present invention.

  The pH (20 ° C.) of the beverage of the present invention is preferably 2 to 7, more preferably 3 to 6.5, and still more preferably 3 to 6, from the viewpoint of tannin stability.

  In addition, the beverage of the present invention is provided by filling a normal packaging container such as a molded container (so-called PET bottle) mainly composed of polyethylene terephthalate, a metal can, a paper container combined with a metal foil or a plastic film, or a bottle. can do. In addition, the packaged beverage may be heat sterilized, and the heat sterilization method is particularly limited as long as it conforms to the conditions stipulated by applicable laws and regulations (the Food Sanitation Law in Japan). Is not to be done. Examples thereof include a retort sterilization method, a high temperature short time sterilization method (HTST method), and an ultra high temperature sterilization method (UHT method). It is also possible to appropriately select the heat sterilization method according to the type of container of the packaged beverage, for example, when the container can be heated and sterilized after filling the container like a metal can. Retort sterilization can be employed. As for PET bottles and paper containers that cannot be sterilized by retort, aseptic filling, hot-pack filling, etc., in which beverages are heat-sterilized in advance under the same sterilization conditions as described above and sterilized in an aseptic environment Can be adopted.

1. Analysis of tannin The amount of tannin in tea extract was determined by the iron tartrate method, using ethyl gallate as the standard solution, and as a converted amount of gallic acid (Reference: “Green tea polyphenol” functional material for food and drink Effective utilization technology series No. 10).
5 mL of a sample was developed with 5 mL of iron tartrate standard solution, dissolved in 25 mL with a phosphate buffer, the absorbance was measured at 540 nm, and the amount of tannin was determined from a calibration curve with ethyl gallate.
Preparation of iron tartrate standard solution: 100 mg of ferrous sulfate heptahydrate and 500 mg of sodium / potassium tartrate (Rochelle salt) were made up to 100 mL with distilled water.
Preparation of phosphate buffer: 1/15 mol / L disodium hydrogen phosphate solution and 1/15 mol / L sodium dihydrogen phosphate solution were mixed and adjusted to pH 7.5.

2. Tannin recovery rate The tannin recovery rate was calculated by the following method.
(1) About the tea extract obtained in the Example or the comparative example, the amount of tannin per 1g of tea leaves was calculated | required.
(2) 10 g of tea leaves were immersed in 430 mL of hot water at 90 ° C. for 1 minute, and the amount of tannin per 1 g of tea leaves was determined for the obtained tea extract.
(3) The ratio of the tannin amount of (1) described above to the tannin amount of (2) described above was determined.

3. Sensory evaluation The tea extract obtained in each Example or Comparative Example was diluted with distilled water so that Brix (20 ° C.) was 0.3 ± 0.1% and the amount of tannin was 69 to 79 mg / 100 mL. A tea drink was prepared. Next, three tea panel drinks each tea beverage, evaluated according to the following criteria, and then the final score was determined by consultation.

Evaluation criteria Score 5: There is an original fragrance and taste of green tea.
4: Green tea has the original fragrance and taste, but has a bitter taste in the latter half of the mouth.
3: The scent and taste of green tea are light or have a strong sensation.
2: Strong bitterness or little taste.
1: Strong bitter taste.

Example 1
(1) First step After adding 26.07 kg of warm water to a kneader extractor (SKN type, manufactured by Mitomo Equipment Co., Ltd.) and adjusting it to 69 ° C., 869 g of green tea leaves (domestic Yabu Kita No. 2 blended crude tea) are added thereto. The mixture was extracted by stirring and mixing at 21 rpm for 6.5 minutes.
(2) Second Step Next, the kneader extractor was tilted to an angle of 2.01 rad at an angular velocity of 0.033 rad / s, and the green tea extract containing tea husks was discharged from the opening onto the screen. A square stainless steel filter (80 mesh, manufactured by Iwai Machine Industry Co., Ltd.) was used as the screen.
(3) Third step On the screen, the tea husk and the green tea extract were separated. In addition, the green tea extract which passed the screen was collect | recovered without wash | cleaning a tea-shell at the time of isolation | separation. The collected green tea extract was centrifuged to remove starch components to obtain a clear green tea extract.
The obtained green tea extract was analyzed and sensory evaluated. The results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 3
In the second step, a green tea extract was obtained by the same operation as in Example 1 except that the angular velocity shown in Table 1 was changed. The obtained green tea extract was analyzed and sensory evaluated. The results are shown in Table 1.

  From Table 1, after obtaining a tea extract from tea leaves in an extractor having an opening upward, the extractor is tilted in a predetermined direction at a constant speed, and the tea extract containing tea shells is discharged from the opening of the extractor. It can be seen that the separation of the tea husk and the tea extract is highly efficient, and a tea extract having a good tannin recovery rate and excellent flavor can be obtained without requiring washing of the tea husk.

Claims (6)

A first step of obtaining tea extract by mixing tea leaves and water in an extraction device having an opening above;
The extraction device is inclined at an angular velocity of 0.0073 to 0.06 rad / s so that the opening forms an inclination angle of ½π rad or more and 2.6 rad or less with respect to the horizontal direction. A method for producing a tea extract, comprising: a second step of discharging to a screen comprising a perforated plate including a large number of holes; and a third step of separating the tea husk and the tea extract on the screen.   The method for producing a tea extract according to claim 1, wherein the extraction device is a kneader extractor.   The method for producing a tea extract according to claim 1 or 2, wherein the tea leaves are one or more selected from non-fermented tea leaves, semi-fermented tea leaves and fermented tea leaves.   The manufacturing method of the tea extract of any one of Claims 1-3 whose temperature of water is 50-95 degreeC.   The manufacturing method of the tea extract of any one of Claims 1-4 whose usage-amount of water is 5-80 mass times with respect to a tea leaf.   The manufacturing method of the tea extract of any one of Claims 1-5 whose mixing time of a tea leaf and water is 2 to 30 minutes.