JP2012183064A - Method for producing tea leaf - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide material tea leaves capable of producing a tea drink having a new scent or taste and free from an unpleasant flavor associated with heat treatment.SOLUTION: A method for producing tea leaves includes the steps of impregnating the tea leaves with an aqueous amino acid containing solution that contains at least one amino acid selected from the group consisting of leucine, valine, and isoleucine, and heating and drying the tea leaves at a temperature of 100 to 200°C.

Description

  The present invention relates to a method for producing tea leaves as a raw material for tea beverages, and more particularly to a method for producing tea leaves capable of producing a flavor-preferred product when used as a container-packed beverage.

  In recent years, many bottled tea beverages filled in containers such as cans and plastic bottles have been developed and marketed. With such diversification of consumer preferences for tea beverages, there is an increasing demand for the development of tea beverages, such as higher-grade, higher-quality, more functional, and new fragrances and tastes. It is growing. In view of this, various methods for processing and processing raw tea leaves have been studied.

  For example, in the case of green tea leaves, a method of spreading an extract extracted from tea leaves separately from the tea leaves brewed in the crude tea production process and drying the tea leaves (Patent Document 1), In the crude tea production process where steaming, filling in a pot or wilt and then heating and pressure-treating tea leaves to reduce the water content, a portion of the tea leaves are taken out and squeezed before heating and pressure-treating is completed. The method for producing tea (Patent Document 2), characterized in that it comprises a step of heating and spraying the juice on tea leaves before completion of the crushed pressure treatment, obtained from tea for dry tea A method for imparting an aroma component (Patent Document 3) has been proposed.

  In addition, when amino acids and proteins are heated, carbonyl compounds, amines, and sulfur-containing compounds mainly composed of hydrogen sulfide can be produced as aroma components, and when carbohydrates coexist with amino acids and proteins, It is known that it acts as an oxidant, and a favorable fragrance is easily generated upon heating, and pyrazines having a very fragrant fragrance can be generated from sugar and amino acid. A processing method in which various amino acids are added and heated using this principle has been reported. For example, by immersing whole grains of threshing buckwheat seeds in a suspension or aqueous solution of an amino acid simple substance and mixture or an amino acid-based natural seasoning, There is a method for producing buckwheat tea with enhanced aroma after roasting, characterized in that the grains are dried, roasted and pulverized (Patent Document 4).

JP 2005-204527 A JP 2007-082526 A JP-A-63-137646 Japanese Patent Laid-Open No. 2005-669

  An object of the present invention is to provide a raw tea leaf advantageous for the production of a tea beverage having an excellent flavor, in particular, a container-packed green tea beverage.

  As a result of intensive investigations to provide a tea beverage that has an unprecedented aroma and taste and can suppress a heat-degraded odor when used as a packaged tea beverage, a solution containing a specific amino acid When the tea leaves were impregnated and fired and dried under specific conditions, it was found that the flavor of the tea leaves can be easily and effectively enhanced, and the present invention has been completed.

That is, the present invention includes, but is not limited to, the following inventions.
(1) A step of impregnating raw tea leaves with an aqueous solution amino acid solution containing at least one amino acid selected from the group consisting of leucine, valine and isoleucine, and heating and drying the impregnated tea leaves at a temperature of 100 to 200 ° C. A method for producing tea leaves, comprising the step of:
(2) The production method according to (1), wherein 45 mg or more of the amino acid is added per 1 kg of raw tea leaves.
(3) The production method according to (1) or (2), wherein the amino acid-containing solution is an extract of green tea leaves.
(4) The production method according to (3), wherein the tea leaf extract is subjected to an enzyme treatment.
(5) A step of impregnating a raw material tea leaf with an aqueous solution amino acid solution containing at least one amino acid selected from the group consisting of leucine, valine and isoleucine, a step of heating and drying the impregnated tea leaf at a temperature of 100 to 200 ° C. A method for producing a tea beverage, comprising: extracting a tea leaf dried by burning with water to obtain a water extract.

  When the tea leaves of the present invention are used, a tea beverage having an excellent flavor can be produced.

It is a figure which shows the amino acid composition of the tea extract analyzed in Example 2. It is a figure which shows the 2-methylbutanal content in the green tea drink prepared using the enzyme treatment green tea concentrate as an amino acid containing solution by the method similar to Example 5 except having changed the firing temperature to 110-170 degreeC. . It is a figure which shows the relationship between firing temperature and the content of various components (2-methylbutanal, 2, 5- dimethyl pyrazine) in manufacture of general roasted tea. In addition, the peak area in FIG. 2, FIG. 3 is an area under the curve concerning the peak of the test substance when the test substance is analyzed.

  As described above, in the present invention, the raw tea leaves are impregnated with an aqueous solution containing a specific amino acid (at least one amino acid selected from the group consisting of leucine, valine and isoleucine), and then a temperature of 100 to 200 ° C. Heat and dry with. From one point of view, the present invention is a method for producing tea leaves, and from another point of view, the present invention is a method for producing a tea beverage using the tea leaves thus obtained.

(Amino acid impregnation process)
The tea leaves referred to in the present invention refer to tea leaves that are used as raw materials for tea beverages that can be extracted and drunk with water or hot water. In the present invention, tea leaves that are subjected to the amino acid impregnation step described later are referred to as raw tea leaves. Specifically, steamed non-fermented tea (green tea) such as sencha, bancha, hojicha, gyokuro, kabusecha, and strawberry tea; unfermented tea such as keen-fried tea such as Ureshino tea, Aoyagi tea and various Chinese teas; Semi-fermented tea such as seed tea, iron kannon tea, oolong tea; teas such as fermented tea such as black tea, Awaban tea, and puar tea. Among them, non-fermented tea (green tea) is one of the preferred embodiments of the present invention because it significantly exhibits the flavor improving effect of 2-methylbutanal and / or 3-methylbutanal of the present invention. The tea leaves used in the present invention are not limited as long as they are extracted and can be drunk, and leaves, stems and the like can be used as appropriate. Also, the form is not limited to large leaves or powders. The harvest time of tea leaves can also be appropriately selected according to the desired flavor, but 3 to 4 teas are preferred.

  In the present invention, tea leaves are impregnated with an aqueous solution containing at least one amino acid selected from the group consisting of leucine (Leu), valine (Val) and isoleucine (Ile) (in the present specification, Sometimes referred to as “amino acid impregnation step”). A preferred soy sauce-like aroma can be enhanced by a combination of this specific amino acid and a heating and drying step described later. And if a tea drink is manufactured using the tea leaf of this invention, it will become the outstanding tea drink by which only the preferable fragrant fragrance was reinforced without accompanying a burning smell and miscellaneous taste.

  According to the study by the present inventors, this preferred soy sauce-like aroma was impregnated with an aqueous solution containing at least one amino acid selected from the group consisting of leucine (Leu), valine (Val) and isoleucine (Ile). If expressed. In particular, leucine enhances not only a fragrant scent but also a scent having a thickness (also referred to as a body feeling or a rich feeling), so that the flavor improving effect of a tea beverage is more remarkable. Accordingly, one preferred embodiment of the present invention is one in which the aqueous amino acid solution contains leucine and further contains valine and / or isoleucine. More preferably, the aqueous amino acid solution contains leucine, valine and isoleucine. When three types of leucine (Leu), valine (Val), and isoleucine (Ile) are included, the ratio is about Leu: Val: Ile = 1: 0.1-10: 0.1-10, preferably 1: 0.1 to 1.0: about 0.1 to 1.0.

  The reason why the aroma of tea leaves is enhanced by the present invention is not clear, and the present invention is not limited to the following assumptions, but 2-methylbutanal (2-methylbutanal) which is a preferred soy sauce-like aroma component ) And / or 3-methylbutanal is presumed to be enhanced by the present invention.

  The fragrant aroma (soy sauce-like aroma) expressed using leucine, valine and / or isoleucine is a group consisting of phenylalanine (Phe), glutamic acid (Glu), glycine (Gly), proline (Pro), and theanine (Theanine) When one or more amino acids selected from the above are used in combination, the thickness increases and a flavor improving effect is exhibited. In particular, phenylalanine has a large fragrance thickness-imparting effect and brings about a significant flavor improving effect. The effect of imparting the thickness of the fragrance is not only the effect of increasing the richness of the tea beverage, but also the effect of maintaining the fragrance even when the heat treatment at the time of producing the container-packed beverage, the effect of masking the heat odor accompanying the heat treatment Also have. When one or more amino acids selected from the group consisting of phenylalanine, glutamic acid, glycine, proline, and theanine are added without using leucine, valine, and isoleucine, flavor-improving effects such as maintenance of aroma and masking of heated odor Therefore, this effect is not limited to specific amino acids (leucine, valine, isoleucine: hereinafter also referred to as amino acid A) and specific amino acids (phenylalanine, glutamic acid, glycine, proline, and theanine: hereinafter also referred to as amino acid B). ) And can be obtained in cooperation with each other. Therefore, when the tea leaf of the present invention is a tea leaf for container-packed tea beverages, in the amino acid impregnation step, at least one selected from the group consisting of leucine, valine and isoleucine (preferably leucine, valine and isoleucine). It is desirable to impregnate an aqueous solution containing 3 amino acids (including 3) and one or more amino acids selected from the group consisting of phenylalanine, glutamic acid, glycine, proline, and theanine.

  The method for impregnating the aqueous amino acid solution is not particularly limited as long as the amino acid can penetrate or adhere to the raw tea leaves. For example, a method of spraying, spreading or applying an aqueous amino acid solution to the raw tea leaves, a method of immersing the tea leaves in an aqueous amino acid solution, and the like can be mentioned. From the viewpoint of allowing amino acids to uniformly impregnate tea leaves, a method of spraying and stirring an aqueous amino acid solution on tea leaves is preferred.

  The amino acid aqueous solution referred to in the present invention may be an amino acid suspension as long as it contains a liquid amino acid. However, from the viewpoint of easy impregnation of the amino acid into the raw tea leaves, the amino acid is dissolved. It is preferably used in the form of a prepared aqueous amino acid solution. The amino acid concentration in the aqueous amino acid solution may be appropriately adjusted according to the solubility of the amino acid, but usually the total amount of the amino acid (A), that is, leucine, valine and isoleucine is 0.01 to 10% by weight in the aqueous amino acid solution, preferably 0. Prepared to be 1 to 2% by weight. Moreover, 1 type chosen from the group which consists of an amino acid (B) which has an effect which gives thickness to the fragrance fragrance derived from 2-methylbutanal and / or 3-methylbutanal, ie, phenylalanine, glutamic acid, glycine, proline, and theanine When the above amino acids are used in combination, the total amount of amino acids (B) is the total amount of amino acids contained in the aqueous amino acid solution (specifically, aspartic acid, glutamic acid, serine, glycine, histidine, arginine, threonine, alanine, proline, theanine) , Tyrosine, valine, methionine, isoleucine, leucine, lysine, phenylalanine), and the total amount of 17 amino acids is preferably 10 to 80% by weight, and preferably 15 to 25% by weight.

  At this time, the amino acid (A) is impregnated with 45 kg or more, more preferably 100 mg or more, further preferably 150 mg or more, particularly preferably 200 mg or more with respect to 1 kg of the raw tea leaves. In the case of 45 mg or more, the unique aroma (soy sauce-like aroma) targeted by the present invention can be sufficiently expressed, and a flavor improving effect can be obtained. Therefore, in the present invention, the total amount of amino acids (A), that is, leucine, valine and isoleucine is preferably about 0.005 to 0.25% by weight with respect to 100 parts by weight of the raw tea leaves, and 0.05 to 0 More preferably, it is about 1% by weight. The upper limit of the amino acid (A) is not particularly limited, but is usually 5000 mg or less, preferably 3000 mg or less, more preferably 2000 mg or less, and particularly preferably about 100 mg or less with respect to 1 kg of the raw tea leaves.

  As the amino acid used in the present invention, a purified amino acid may be used, or a plant extract containing an amino acid may be used as it is or after being purified (including crude purification). Here, a green tea extract is suitably exemplified as the plant extract. Usually, the green tea extract contains many amino acids such as theanine, glutamic acid, aspartic acid, and methionine. The amino acid (A) valine, leucine, and isoleucine, which are the active ingredients of the present invention, are compatible with these amino acids (A). It is known that the content of the amino acid (B) phenylalanine, glycine, and proline that acts additionally or synergistically to further improve the flavor is small. Therefore, when using a green tea extract, it is preferable to perform a treatment that increases the concentration of amino acid (A) or amino acid (B) by applying a physical or chemical treatment. Here, examples of the physical or chemical treatment include enzyme treatment, acid treatment, high-temperature and high-pressure treatment, miniaturization treatment, and ultrasonic treatment. Of these, enzyme treatment is preferable from the viewpoint of selectively controlling the reaction of amino acids.

  As the enzyme treatment of the green tea extract, any method can be used as long as the enzyme acts on proteins and fibers in the green tea leaves and / or tea extract to increase the amino acid concentration in the extract. But you can. For example, enzyme extraction (a method of extracting green tea leaves mixed with enzymes with water (hot water) or a method of extracting green tea leaves with water added with enzymes (hot water)), or water (hot water) from green tea leaves The method of adding and mixing an enzyme with the green tea extract extracted by (1) is mentioned. As the enzyme, protease, α-amylase, cellulase, hemicellulase, pectinase, protopectinase, glutaminase and the like can be used singly or in combination. The conditions for the enzyme treatment may be appropriately selected in view of the optimum conditions for the enzyme used.

  When a green tea extract is used as an aqueous amino acid solution, if a green tea extract containing a large amount of catechins is used, bitterness and astringency may be generated in the roasting process of the present invention, or a taste may be generated during heat sterilization in tea beverage production. There is a case. Therefore, the green tea extract used in the present invention is preferably subjected to a catechin removal process. Here, the catechins in the present specification represent a generic name of catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate and epigallocatechin gallate. Specifically, in the green tea extract, the ratio of the total amount of catechins to the tea leaf-derived solid content is 15.0 wt% or less, preferably 13.5 wt% or less, more preferably 10.0 wt% or less, It is particularly preferably removed so as to be 8.0% by weight or less. In addition, the Brix (soluble solid component amount) of the tea extract is usually about 0.2 to 20%, preferably 5 to 20%, more preferably 10 to 20%. The method for removing catechins is not particularly limited. For example, a method for removing catechins from a green tea extract by resin (adsorption), an aqueous solvent is brought into contact with green tea leaves to obtain a green tea leaf extract, and then the extract is used. The method of removing (disposing) is mentioned. In particular, since catechins have the property of being easily extracted at high temperatures, there is a method in which green tea leaves are brought into contact with high-temperature water to obtain a high-temperature extract containing a large amount of catechins, and this high-temperature extract is removed (discarded). Is preferred.

  Tea leaves for tea beverages used for extraction are usually produced through 1) a crude tea production process and 2) a tea production process. 1) In the manufacturing process of crude tea, (i) fresh tea plucking, (ii) air blowing / heating, (iii) steaming, (iv) cooling, (v) leaf punching, (vi) crude koji, (vii) koji Crude tea is obtained through processes such as koji, (viii) medium koji, (ix) refined koji, and (x) drying. Here, (ii) in the air blowing / heating process, in order to prevent the quality degradation of fresh tea and maintain the freshness, air with high humidity is sent to maintain moisture and reduce respiratory heat, and (iii) in the steaming process The odor enzyme that oxidizes tea leaves is stopped by steaming the tea leaves, and the blue odor is removed while keeping the color of the tea leaves green. (iv) The cooling process is a process of maintaining the color and flavor of the tea leaves by sending wind to the hot tea leaves and rapidly cooling them to room temperature so that there is no unevenness. The process is a process to improve the drying effect by removing hot steam from the dried hot air and removing steam dew on the tea leaves in order to improve the color and flavor of the tea leaves and shorten the time of the next rough koji process. . (vi) In the rough kneading process, the tea leaves are softened by squeezing them, and in order to reduce the moisture in the inside, the dry hot air is sent in, applying the striking pressure, and gently rubbing the tea leaves while rubbing and pressing (vii) In the cocoon process, the tea leaves are made into a lump and mixed with high pressure without heating (this breaks down the tea leaf tissue and makes it easier to produce components such as tea taste, while at the same time making the moisture uniform) Plan). Furthermore, (viii) in the middle cocoon process, the tea leaves that have become clumps in the twisting process are crushed while sending hot air that has been dried, and then twisted and dried to facilitate shaping in the next process. Then, the tea leaves are dried to remove moisture, and are squeezed only in a certain direction so as to be squeezed by human hands, and the tea leaves are arranged in a narrow and elongated shape unique to green tea, and finally (x) the drying process, the finishing process Reduce the water content (about 10-13%) of the tea leaves obtained to about 5% by hot air drying. In addition, 2) tea-making processes include a pre-ignition method (a method that separates and shapes after drying in a fire) or a post-fire method (a method that performs heat-and-dry after separating and shaping). After that, "finishing tea" is obtained.

  The tea leaves (raw material tea leaves) subjected to the amino acid impregnation step of the present invention may be crude tea or finished tea. Moreover, the tea leaf of the arbitrary timings of a rough tea manufacturing process may be sufficient. From the viewpoint of easy impregnation of the aqueous solution of the amino acid into the raw tea leaves and easy control of the quality, it is preferable to use the crude tea that has undergone the step (x) as the raw material tea leaves, and to perform the amino acid impregnation step and the flame drying step.

(Fire-filling drying process)
In the present invention, the tea leaves impregnated with the above-mentioned specific amino acid aqueous solution are subjected to a fire-drying process at a temperature of 100 to 200 ° C. In the case of drying by heating, with a little moisture remaining, heat is applied more than when drying, and this enhances the unique fragrant aroma (soy sauce-like aroma). When the degree of dry-fire is strong, the simple incense, i.e., the smell close to burnt odor, becomes strong, and a preferable fragrant fragrance such as 2-methylbutanal and / or 3-methylbutanal becomes difficult to perceive. Therefore, it is preferable that 2-methylbutanal and / or 3-methylbutanal is a fire scent of 2,5- (or 2,6-) dimethylpyrazine (2,5 (6) -dimethylpyrazine). It is desirable to roast so as to contain 5 to 50 times, more preferably 1 to 30 times.

  According to the study by the present inventors, there is a tendency that there is no difference in the amount of 2- (or 3-) methylbutanal produced above a certain temperature range even when the temperature of the flame drying is increased (see FIG. 2). ). On the other hand, when the temperature of the heating and drying is increased, 2,5- (or 2,6-) dimethylpyrazine, which is an incense stick, is rapidly increased. Therefore, as a method for adjusting the ratio of 2-methylbutanal and / or 3-methylbutanal content to 2,5- (or 2,6-) dimethylpyrazine content within the above preferred range, amino acid-impregnated tea leaves An example is a method of heating so that the product temperature reaches 100 to 200 ° C, preferably 110 to 170 ° C, more preferably 130 to 160 ° C, and particularly preferably 130 to 150 ° C. The time until the amino acid-impregnated tea leaf product temperature reaches the above temperature, that is, the flame drying time varies depending on the apparatus, but can be appropriately set by those skilled in the art. For example, when a drum-type drying apparatus is used, 3 to 60 minutes, preferably 5 to 45 minutes after the amino acid-impregnated tea leaves are put into the drum heated to a temperature higher than the firing temperature (the reached temperature of the tea leaves). Minutes, more preferably about 10 to 30 minutes. The 2-methylbutanal, 3-methylbutanal content and 2,5- (or 2,6-) dimethylpyrazine content in the tea leaves dried by heating can be measured by gas chromatography.

  An apparatus that can be used in the fire-drying process is not particularly limited and can be used. For example, a direct-fire type, a far-infrared type or the like can be used, and the shape thereof may be a drum type or a plate type. The water content of the tea leaves obtained in the fired drying step is usually 5% or less, preferably about 1% or less.

  When crude tea (or tea leaves at any timing in the crude tea production process) is used as the raw tea leaves of the present invention, it is possible to handle the heating and drying in the tea production process as the heating and drying process of the present invention, from the viewpoint of workability. This is a useful method. In this case, the heating and drying timing may be a pre-ignition method or a post-fire method. From the viewpoint of quality control and workability, a particularly preferred embodiment of the present invention is an amino acid impregnation step in which an aqueous solution of amino acid is impregnated into tea leaves brewed in the crude tea production step, and then heated and dried in the tea production step. It is the manufacturing method of the tea leaf which performs a heating-in-drying process.

  A roasted tea leaf is known as a tea leaf to be subjected to a fire-drying process. According to the study by the present inventors, in the production of general roasted tea, the content of 2,5-dimethylpyrazine increases exponentially as roasting becomes stronger, while the content of 2-methylbutanal is It increases proportionally (see FIG. 3 (1)). That is, a high correlation is recognized between the logarithm of the amount of 2,5-dimethylpyrazine and the amount of 2-methylbutanal (see FIG. 3 (2)). However, after the production method of the present invention, that is, impregnating the raw tea leaves with an aqueous solution containing a specific amino acid (at least one amino acid selected from the group consisting of leucine, valine and isoleucine), at a temperature of 100 to 200 ° C. In tea leaves obtained by heating and drying, 2-methylbutanal and 2,5-dimethylpyrazine are contained in a ratio different from the conventional ratio, and 2-methylbutanal is a particularly high proportion of 2,5-dimethylpyrazine. Can be produced.

(Manufacture of tea beverages)
Container-packed tea beverages are generally obtained by extracting tea leaves with an aqueous solvent to obtain a tea extract, adjusting the concentration of this tea extract to the drinking concentration, and then placing it in sealed containers such as cans and PET (PET) bottles. Manufactured by encapsulation. Also in the production of the tea beverage of the present invention, tea leaves produced through the above-described steps, that is, the amino acid impregnation step and the fire-drying step (hereinafter referred to as “tea leaf of the present invention”) are used as raw materials and are subjected to the extraction step. An extract is obtained, and a tea beverage can be produced using this tea extract.

  The tea leaves used as the raw material for the tea extract may be the tea leaves of the present invention as the total amount of the raw tea leaves, or may be mixed with other tea leaves and used as a part of the raw tea leaves. In the extraction step of extracting from raw tea leaves with an aqueous solvent, extraction is performed with an arbitrary water such as tap water or deionized water, preferably at an extraction water temperature of 40 to 95 ° C, more preferably 70 to 95 ° C. A preferable extraction ratio (weight ratio) is about 10 to 100 parts, preferably about 25 to 50 parts, of extracted water with respect to 1 part by weight of raw tea leaves. At the time of extraction, it may be stirred or may not be stirred.

  In a preferred embodiment, the extracted tea extract is immediately filtered in stages using a wire mesh to remove residues such as tea husk and cooled to 10-40 ° C. using, for example, a plate-type exchanger. To do. Furthermore, it is preferable to remove insoluble components using a continuous centrifugal separator or flannel filtration, and the centrifugal conditions are usually 4000 to 9000G. The centrifuge may be of any type. Further, flannel filtration may be performed, for example, by using flannel cloth or the like.

  Thereafter, if necessary, an antioxidant or a pH adjuster such as L-ascorbic acid or sodium hydrogen carbonate is added to the obtained filtrate, and preferably the pH is adjusted to 5.0 to 7.0. Good. The pH-adjusted extract is diluted so that the soluble solid content (Brix) of the final preparation becomes a desired value (for example, 0.1 to 0.5, preferably 0.2 to 0.4), The solid content concentration may be adjusted.

  In a preferred embodiment, the prepared liquid thus obtained is sterilized in order to enhance the storage stability. The sterilization treatment may be performed after the preparation liquid is filled into a sealed container, or may be filled into the container after sterilization. A container is not specifically limited, A paper pack, a bottle, a can, a plastic bottle etc. are used. Sterilization may be appropriately selected according to the type of container and storage conditions, such as UHT sterilization, retort sterilization, and plate sterilization. Specifically, if the container can be sterilized by heating after filling into a container such as a can or bottle, retort sterilization is adopted under the sterilization conditions stipulated in the Food Sanitation Law, and retort sterilization is performed like a plastic bottle or paper pack. For those that cannot, pre-sterilization conditions similar to the above, for example after sterilization at high temperature and short time in a plate heat exchanger, cooled to a certain temperature, and filled into a container by a method such as hot pack filling or aseptic filling Such a method is adopted.

  In addition, the manufacturing method of the tea beverage of the present invention includes an embodiment in which the tea extract obtained from the tea leaves of the present invention is added as an additive for tea beverages, that is, an aroma enhancer or a kokumi enhancer. It is an embodiment in which a tea extract is obtained from the tea leaves of the present invention through the above-described extraction step, and this is blended with a tea beverage preparation liquid (preparation liquid prepared mainly from tea extract liquids obtained from other tea leaves). .

  The container-packed tea beverage produced in this way has a fragrant aroma that is considered to be caused by 2-methylbutanal and / or 3-methylbutanal resulting from the tea leaves of the present invention, and the heated odor is suppressed. , Have an excellent flavor. In addition, when a tea beverage having a low Brix (specifically, a tea beverage having a Brix of 0.2% or less) is produced, it has an odor that is equal to or higher than that of a conventional product (a product having a high Brix). In addition to the aroma advantage that the heat-degraded odor is suppressed more than the product, it also has the advantage that turbidity and precipitation associated with long-term storage are suppressed. Furthermore, it is a low-caffeine tea beverage that has low irritation and bitterness and is easy to take on a daily basis (specifically, the caffeine-containing weight relative to the whole beverage is 80 to 200 ppm, preferably 80 to 160 ppm, more preferably 80 (About ~ 130ppm) is produced, it has the same or better body and drinking response as conventional products (those with high caffeine content), and has the flavor advantage that bitterness is suppressed compared to conventional products be able to.

  The container-packed tea beverage produced in this way contains the component (A) 2-methylbutanal and / or 3-methylbutanal and the component (B) 2,5-dimethylpyrazine, The content (total amount) of the component (A) is 23-100 ppb (preferably 25-100 ppb, more preferably 27-100 ppb), and the content of the component (B) is 5-50 ppb (preferably 5-40 ppb, more When prepared so as to be preferably 5 to 30 ppb), a flavor-preferred novel container-packed beverage can be produced.

  Such an aspect of the present invention can be understood as a method for improving the flavor of tea leaves or tea beverages from one viewpoint.

  EXAMPLES Hereinafter, although an Example is shown and the detail of this invention is demonstrated concretely, this invention is not limited to this. Further, unless otherwise specified in the present specification, the concentration and the like are based on weight, and the numerical range is described as including the end points.

Example 1. Production of green tea beverage-addition of amino acids 1% aqueous solutions of various amino acids were prepared . Here, amino acids include (i) aspartic acid (Asp), (ii) glutamic acid (Glu), (iii) serine (Ser), (iv) glycine (Gly), (v) histidine (His), (vi ) Arginine (Arg), (vii) Threonine (Thr), (viii) Alanine (Ala), (ix) Proline (Pro), (x) Theanin, (xi) Tyrosine (Tyr), (xii) Valine 17 types of (Val), (xiii) methionine (Met), (xiv) isoleucine (Ile), (xv) leucine (Leu), (xvi) lysine (Lys), (xvii) phenylalanine (Phe) were used ( All made by Nacalai Tesque, L).

The prepared amino acid aqueous solution is impregnated with unburned green tea leaves (raw tea; No. 3 tea, yabukita) (raw tea leaves) by spraying so that the weight ratio of raw tea leaves: amino acid aqueous solution is 1: 0.2. After that, it was fired and dried using a fire-fired machine. The conditions for heat drying are as follows. Here, the firing time refers to the time from the introduction of the amino acid-impregnated tea leaves into the firing machine until the removal, and the firing temperature refers to the final temperature reached by the tea leaves.
・ Fire-filling machine: Terada Seisakusho, TR-10
・ Drum temperature: 200 ℃
・ Drum rotation speed: 12rpm
・ Taking time: 15-20 minutes ・ Taking temperature: 150 ° C.
As a control, beverage tea leaves were obtained in the same manner except that the amino acid aqueous solution was changed to water.

  17 types of tea leaves sprayed with amino acids and dried by heating were weighed 2 g each and extracted with 200 g of hot water for 5 minutes to obtain an extract (Brix: 0.25%).

  Table 1 shows the results of sensory evaluation of the obtained green tea extract. The green tea extract is evaluated in four stages, and the evaluation criteria are × (same as control), △ (good fragrance is slightly enhanced), ○ (good fragrance is enhanced), ◎ (good fragrance) Is remarkably enhanced). As is clear from Table 1, the neutral amino acids Val, Ile and Leu, which have an alkyl chain with a molecular weight of 100 or more, have a unique soy sauce-like fragrance that is perceived as preferred without a burning odor or miscellaneous taste. It was revealed that it can enhance the fragrant scent. In particular, Leu became a green tea extract having an excellent flavor with a rich and harmonious taste with a rich scent as well as a fragrant scent. Moreover, when Phe, Glu, Gly, Pro, and Theanine were added, the scent thickness increased as a whole, and in particular, Phe was found to have a great effect of imparting scent thickness.

Example 2 Manufacture of green tea beverage-impregnation of tea extract (1) Manufacture of tea extract An extract containing an amino acid at a high concentration was manufactured by the following method. First, 10 g of green tea leaves (heating degree: medium) were sealed in an airtight container with a stirrer, and 180 mL of 40 ° C. ion exchange water was added to immerse the green tea leaves. Thereto was added 0.2 g of protease preparation (Mitsubishi Chemical Foods Co., Ltd. “Coclase P”), and the mixture was stirred for 16 hours while being kept at 40 ° C. to perform enzyme treatment. Thereafter, the obtained enzyme-treated solution was heated at 90 ° C. for 10 minutes to deactivate the enzyme to obtain an enzyme extract (sample A: with enzyme). Further, a green tea extract (tea extract) was similarly obtained except that no enzyme was added (sample B: no enzyme).

  The amino acid composition of Sample A and Sample B was analyzed by HPLC. Specific measurement conditions are as follows. As standard substances, 17 kinds of amino acids (aspartic acid, glutamic acid, serine, glycine, histidine, arginine, threonine, alanine, proline, theanine, tyrosine, valine, methionine, isoleucine, leucine, Lysine and phenylalanine) were used.

  Table 3 shows the amino acid analysis results of the tea extract. Moreover, the amino acid analysis result of Val, Ile, and Leu in Table 3 is shown in FIG. As is clear from FIG. 1, the ratio of Val, Ile, and Leu is increased in the tea extract (sample A) that has been subjected to the enzyme treatment, compared to the tea extract that has not been subjected to the enzyme treatment (sample B). When the ratio [(Val + Ile + Leu) / (Met)] with the amino acid Met expressing an unfavorable flavor in Example 1 was calculated, 0.16 was obtained when the enzyme treatment was not performed, and 1.47 when the enzyme treatment was conducted It became.

(2) Production of tea leaves impregnated with tea extract As amino acid-containing solutions to be permeated into tea leaves, each was prepared as follows.
-1% Amino Acid Aqueous Solution: An amino acid from Nacalai Tesque Co., Ltd. was used to prepare an amino acid composition similar to that of the enzyme-treated green tea extract (sample A) of (1). That is, the total amount of 17 amino acids was 1% by weight, and the total amount of amino acids A (Val, Leu, Ile) was 0.2% by weight. The concentration of catechins was 0% by weight.
-Green tea extract: Prepared by extracting commercially available green tea leaves (Yabukita, No. 1 tea) for 5 minutes in hot water with a tea leaf ratio of 20 times. The total amount of 17 amino acids was 0.2% by weight, of which the total amount of amino acids A (Val, Leu, Ile) was 0.0008% by weight. Further, the concentration of catechins was measured and found to be 0.35% by weight.
Green tea concentrate (amino acid 1%): The above green tea extract was prepared by concentration under reduced pressure so that the total concentration of 17 amino acids was 1%. The total amount of amino acids A (Val, Leu, Ile) in this green tea concentrate was 0.004% by weight, and the concentration of catechins was 1.75% by weight.
Enzyme-treated green tea concentrate: The tea extract (sample A) prepared in Example 2 (1) was adjusted by concentration under reduced pressure so that the concentration of 17 amino acids was 1%. The total amount of amino acids A (Val, Leu, Ile) in the enzyme-treated green tea concentrate was 0.2% by weight, and the concentration of catechins was 1% by weight.

These amino acid-containing solutions are sprayed and stirred so that the weight ratio of the raw tea leaves: amino acid-containing solution is 1: 0.2 with respect to green tea leaves (raw tea; No. 3 tea, Yabukita) (raw tea leaves) that have not been fired. Then, after impregnation, it was fired and dried. At this time, the total amount of amino acids added to the raw tea leaves was 2000 mg / kg, and the total amount of valine, isoleucine and leucine (Val + Ile + Leu) when using the enzyme-treated green tea concentrate was 460 mg / kg. . The conditions for drying by heating are as follows.
・ Fire-filling machine: Terada Seisakusho, TR-10
・ Drum temperature: 200 ℃
・ Drum rotation speed: 12rpm
・ Taking time: 15-20 minutes ・ Taking temperature: 150 ° C.

(3) Manufacture of green tea beverage 2 g each of the tea leaves (4 types) impregnated with the amino acid-containing solution obtained in (2) were weighed and extracted with 200 g of hot water for 5 minutes to obtain a green tea beverage. The results of sensory evaluation are shown in Table 4. When Val, Ile, and Leu are added in a large amount compared to normal green tea extract, a unique and unique soy sauce-like aroma is felt, especially when enzyme-treated green tea extract is added. found. In addition, if the green tea extract was only concentrated to match the total amino acid concentration, the amount of Val, Ile and Leu added was small, and the aroma did not change significantly. Added, there was a tendency for astringency to become stronger.

Example 3 FIG. Production of Containerized Green Tea Beverage A green tea beverage was produced by using the tea leaves impregnated with the enzyme-treated green tea concentrate obtained in Example 2 (2) and fired and dried. That is, 7 g of tea leaves are weighed and extracted with 200 g of hot water for 5 minutes, after removing the tea husk, cooled to 30 ° C. or lower and subjected to clarification by centrifugation, and the resulting filtrate is used as an antioxidant. L-ascorbic acid was adjusted to pH 6.1 by adding sodium bicarbonate as a pH adjuster. Thereafter, the pH-adjusted extract was made up to 1 L so that the soluble solid content (Brix) of the final preparation was 0.25%. The obtained preparation was filled in a can, retort sterilized at 130 ° C. for 1 minute, and cooled in a refrigerator at 5 ° C. to obtain a green tea beverage packed in a container. Further, as a control, tea leaves produced in the same manner except that the tea extract was not sprayed were used to produce a container-packed green tea beverage in the same manner.

  When compared with drinking, the container-packed green tea beverage of the present invention was a green tea beverage having an excellent flavor without a heated odor, with enhanced fragrance, sweetness and richness even after sterilization. Moreover, a good aroma was maintained even after refrigerated storage, and an unfavorable aroma such as a heat-deteriorating odor was not felt.

Example 4 Component analysis Various component analyzes were performed on the container-packed green tea beverage obtained in Example 3. In addition, as a comparison, except for using commercially available sencha leaves or roasted tea leaves, a container-packed green tea beverage (Comparative Examples 1 and 2) produced in the same manner as in Example 3 and a commercially available container-packed beverage (green tea beverage A, green tea beverage) The same component analysis was performed for B and roasted tea beverage C). For analysis of caffeine and caffeine, HPLC is used, and for analysis of various aroma components (2-methylbutanal (2MB), 3-methylbutanal (3MB), and 2,5-dimethylpyrazine (DM)) GC / MS was used. Each analysis method is described below.

(HPLC)
Analytical apparatus: Tosoh Corporation, TOSOH HPLC system LC8020 model II [multi-station: LC-8020, pump: CCMC-II, autosampler: AS-8021, detector: UV-8020, column oven: CO-8020, online degasser : SD-8023]
Analysis conditions: [Column: TSKgel ODS-80Ts QA, eluent A: 10% acetonitrile / water 0.05% TFA, eluent B: 80% acetonitrile / water 0.05% TFA, flow rate: 1.0 ml / min, Temperature 40 ° C., detection: UV 275 nm]

(GC / MS)
5 ml of the sample solution is put in a 20 ml glass bottle with a screw (diameter: 18 mm, manufactured by Gestel), sealed with a metal lid with a polytetrafluoroethylene (PTFE) septum (manufactured by Gestel), and solid phase microextraction method (SPME) The fragrance component was extracted at The quantification was performed by the standard addition method after correcting the peak area detected in the SIM mode of GC / MS using the detected value of n-butanal as an added internal standard.
The sources for the reagents used are as follows.
・ 2-methylbutanal: Wako Pure Chemical Industries ・ 3-methylbutanal: Sigma-Aldrich ・ 2,5-dimethylpyrazine: Tokyo Chemical Industry ・ n-butanal: Kanto Chemical
SPME fiber: StableFlex / SS, 85 μm, Carboxen / PDMS (manufactured by Spelco), fully automatic volatile component extraction and introduction device: MultiPurposeSampler MPS2 (manufactured by Gester)
Analysis conditions: Preheating: 70 ° C. for 5 minutes, stirring: None, volatile component extraction: 70 ° C. for 50 minutes, volatile component desorption time: 10 minutes, equilibration after desorption: 300 ° C. for 20 minutes, GC oven: Agilent 6890N (Manufactured by Agilent Technologies), column: HP-5MS, 30 m × 0.25 mm i. d. , 1 μm (manufactured by Agilent Technologies), GC temperature condition: 40 ° C. (5 minutes) → 10 ° C./minute→100° C. → 5 ° C./minute→160° C. → 20 ° C./minute→280° C. (6 minutes), carrier gas : Helium, 1.6 ml / min, constant flow mode, injection: splitless method, inlet temperature: 250 ° C., mass spectrometer: Agilent 5973inert (manufactured by Agilent Technologies), measurement method: simultaneous scan & SIM measurement, scan range: m / z35 to 300, SIM parameters: m / z57 (for detecting 2-methylbutanal), 58 (for detecting n-butanal and 3-methylbutanal), 108 (for detecting 2,5-dimethylpyrazine), 109 (2 -Acetylpyrrole detection), analysis software: ChemStation (Agilent Techno) THESE Co., Ltd.).

  Table 5 shows the results. The production method of the present invention, that is, the raw tea leaves are impregnated with an aqueous solution containing a specific amino acid (at least one amino acid selected from the group consisting of leucine, valine and isoleucine), and then heated and dried at a temperature of 100 to 200 ° C. The container-packed tea beverage produced using the tea leaf extract obtained in the above manner is compared with the container-packed tea beverage produced using the conventional tea leaf extract. It was confirmed that Nar was a tea beverage containing a specific high proportion of 2,5-dimethylpyrazine.

Example 5 FIG. Production of Green Tea Beverage As the amino acid-containing solution, the enzyme-treated green tea concentrate of Example 2 (2) was used. Amino acid-containing solution is 1: 0.02 (ratio of amino acid-containing solution with respect to tea leaf weight) with respect to green tea leaves (raw tea; No. 3 tea, Yabukita) (raw tea leaves) unheated amino acid-containing solution: 2%), 1: 0.05 (amino acid-containing solution 5%), 1: 0.1 (amino acid-containing solution 10%), 1: 0.2 (amino acid-containing solution 20%). After impregnation, the inking and drying were performed in the same manner as in Example 2 except that the inking temperature was changed to 110 to 170 ° C. In addition, water (0% amino acid) was impregnated and similarly fired and dried to obtain a control tea leaf. Two grams of these tea leaves were weighed and extracted with 200 g of hot water for 5 minutes to obtain a green tea beverage. The amounts of various amino acids added to the raw tea leaves in the amino acid impregnation step are as shown in Table 6.

As a result of sensory evaluation, compared to the control, the green tea beverage produced using tea leaves impregnated with an amino acid solution expresses a preferred soy sauce-like aroma and can enhance the fragrant aroma, and all panelists ( 5 people) were judged to be tea beverages having a flavor superior to that of the control. From this, it was confirmed that it is preferable to impregnate 45 kg or more of amino acid (A) (total amount of leucine, valine and isoleucine) with respect to 1 kg of raw tea leaves, and to perform a flame treatment.

Claims (5)

A step of impregnating a raw material tea leaf with an aqueous solution amino acid solution containing at least one amino acid selected from the group consisting of leucine, valine and isoleucine, and a step of heating and impregnating the impregnated tea leaf at a temperature of 100 to 200 ° C.,
A method for producing tea leaves.   The production method according to claim 1, wherein 45 mg or more of the amino acid is added per 1 kg of raw tea leaves.   The production method according to claim 1 or 2, wherein the solution containing an amino acid is an extract of green tea leaves.   The production method according to claim 3, wherein the tea leaf extract is subjected to an enzyme treatment. A step of impregnating the raw tea leaves with a solution amino acid aqueous solution containing at least one amino acid selected from the group consisting of leucine, valine and isoleucine,
Burning and drying the impregnated tea leaves at a temperature of 100 to 200 ° C .;
A step of extracting the dried tea leaves with water to obtain a water extract,
A method for producing a tea beverage, comprising: