JP4852376B2 - Method for producing green tea extract - Google Patents

Description

  The present invention relates to a method for producing a green tea extract having a high content of non-polymer catechins, weak bitterness and astringency and good flavor.

  As an effect of non-polymer catechins, an effect of suppressing cholesterol elevation has been reported (for example, see Patent Document 1). In order to express such a physiological effect, it is necessary to drink 4 to 5 cups of tea per day for an adult. Therefore, in order to ingest a large amount of non-polymer catechins more easily, A technique for blending non-polymer catechins at a high concentration has been desired.

A method for containing non-polymer catechins at a high concentration in a green tea beverage includes a method of extracting a large amount of catechins from green tea leaves, and uses a concentrate of green tea extract (for example, see Patent Document 2). Thus, there is a method of adding non-polymer catechins to a beverage in a dissolved state.
However, the method for extracting a large amount of catechins from green tea leaves has a problem that the bitterness and astringency derived from the green tea leaves become stronger if it is simply extracted at a high concentration.
The bitterness and astringency derived from green tea leaves are considered to be mainly due to non-polymer catechins. Among non-polymer catechins, free catechins have a weak bitterness and bitterness, ester catechins have a bitter taste and astringency, and ester catechins have a bitter taste and a bitter taste. It is known that astringency is strong (Patent Documents 1 and 2).

As a means for improving the extraction efficiency of green tea components, a method of extracting tea leaves after pulverization is also known (Patent Documents 3 to 5).
However, the green tea extract obtained by this method contains a high concentration of non-polymer catechins, but has a strong bitterness and astringency, and is not satisfactory when used as a beverage for long-term consumption. There wasn't.
JP-A-60-156614 Japanese Patent Laid-Open No. 60-13780 JP-A-47-5294 JP-A-52-39476 Japanese Patent Laid-Open No. 3-108444

  An object of the present invention is to provide a method for producing a green tea extract having a high catechin content, a weak bitterness and astringency, and a good flavor.

  As a result of various studies to achieve both efficient extraction of catechins from green tea and improvement of bitterness and astringency, the present inventor performed CTC treatment on fresh tea leaves subjected to enzyme inactivation treatment instead of ordinary pulverization treatment. And then extracting the dried green tea leaves to a certain amount of water using a certain amount of extraction solvent, a green tea extract with a high non-polymer catechin content, weak bitterness and astringency and good flavor It was found that it can be obtained.

  In the present invention, the enzyme-inactivated fresh tea leaves are subjected to CTC treatment, dried until the water content is 20% by mass or less, and then extracted under the condition that the mass ratio of the extraction solvent to the tea leaves during extraction is 30 times or less. The present invention provides a method for producing a green tea extract.

  According to the present invention, the concentration of non-polymer catechins in the solid content of the green tea extract is as high as 20 to 40% by mass, and the content (gallate body ratio) of gallic acid ester in the non-polymer catechins is 40 to 40%. A green tea extract having a low bitterness and astringency and good flavor is obtained. Such a green tea extract is useful as a packaged beverage containing non-polymer catechins in a high concentration.

  Non-polymer catechins in the present invention are non-epimeric catechins such as catechin, gallocatechin, catechin gallate and gallocatechin gallate and epi-catechins such as epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate Is a collective term.

  Examples of the fresh tea leaves used in the present invention include Camellia, such as C.I. sinensis and C.I. Examples include tea leaves obtained from assamica, Yabuki species, or hybrids thereof. These fresh tea leaves are subjected to enzyme inactivation treatment to prevent fermentation. Examples of the enzyme inactivation treatment include steaming heat treatment, hot water soaking, and kettle roasting treatment. Among these, the kettle roasting treatment is preferably steaming heat treatment and hot water soaking because a change in flavor due to heat history is observed. Steaming heat treatment or hot water immersion is preferably 90 to 120 ° C. and 10 seconds to 3 minutes, and in the case of cooking in a kettle, 300 to 400 ° C. and 5 to 20 minutes are preferable. Examples of the tea leaves that have been subjected to enzyme inactivation treatment include sencha, gyokuro, and tencha. (Japan Tea Instructor Course I NPO Japan Tea Instructor Association / Production / Supervision NPO Japan Tea Instructor Association / Issue 2004, Nippon Tea Zensho Yasumoto Tonoue / Hiroko Tonoue / Author Rural Association of Rural Mountain Fishing Village / Issued 1999)

In the present invention, fresh tea leaves subjected to enzyme inactivation treatment are first subjected to CTC treatment. Here, CTC processing is processing means used for black tea processing, and refers to processing that performs processing of crushing, tearing, and rounding (Curl) at a time, and is performed using a CTC processing device. .
The mechanism of the CTC processing device is that tea leaves pass through the gap between two stainless steel rollers, and the rotation speed of the rollers is different from 700 to 70 times per minute, so the tea leaves are processed between the two. It has become so. The tea leaves are entrained by the rotation of the roller, the tea leaves are torn by the protrusions carved on the surface of the roller, and the tea leaves are rounded and shaped into granules by the grooves carved diagonally. An example of such a CTC processing apparatus is a CTC machine devised in 1930 by W. Mackercher. (The World of Black Tea Yasumasa Araki / Author Shibata Shoten Co., Ltd./Published in 2001, Encyclopedia of Green Tea Hiroshi Takano, Yozo Tanimoto, Isao Tomita, Kiyoshi Iwasa, Toshiyuki Nakagawa, Masuhide Teramoto, Shinichi Yamada / Writing Japan Tea Business Central Association / Supervision Shibata Shoten Co., Ltd./Issued 2002 Japanese Tea Instructor Course I NPO Japan Tea Instructor Association / Production / Supervision NPO Japan Tea Instructor Association / Issued 2004) This CTC is usually used for green tea processing Not done. This CTC treatment improves the extraction efficiency of non-polymer catechins and reduces bitterness and astringency.

  The CTC-treated tea leaves are dried until the water content is 20% by mass or less. This drying process improves the extraction efficiency of non-polymer catechins. The drying conditions may be such that the water content is 20% by mass or less and varies depending on the water content of the raw tea leaves. For example, when steamed and heat-treated tea leaves are the raw materials, drying is performed at 50 to 200 ° C. for 10 minutes to 1 hour. It is preferable to do this. The preferable water content of the dried tea leaves is 2 to 20% by mass, further 2 to 15% by mass, and further 2 to 8% by mass. It is preferable to use a belt conveyor type dryer as the dryer.

  The obtained dried tea leaves are extracted under the condition that the mass ratio (extraction ratio) of the extraction solvent to the tea leaves at the time of extraction is 30 times or less. When the mass ratio of the extraction solvent exceeds 30 times, the gallate content of non-polymer catechins increases, and the bitterness and astringency become unfavorable. A preferable mass ratio is 5 to 30 times, further 5 to 25 times, and particularly preferably 5 to 20 times.

  Examples of the extraction solvent include water and an aqueous ethanol solution, with water being preferred. The extraction is preferably performed with warm water or hot water. The temperature at the time of extraction from tea leaves is preferably 60 to 100 ° C., more preferably 65 to 100 ° C. from the viewpoint of increasing the extraction efficiency of non-polymer catechins and the flavor. The extraction time from tea leaves is preferably 1 to 60 minutes, more preferably 1 to 30 minutes, and further preferably 1 to 10 minutes. If the extraction time is too short, elution of the non-polymer catechins is insufficient, and if it is too long, the heat-denatured isomerization reaction of the non-polymer catechins proceeds. Moreover, you may add organic acids or organic acid salts, such as sodium ascorbate, to the water at the time of extraction previously. Moreover, you may use together the method of extracting in so-called non-oxidative atmosphere, ventilating boil degassing and inert gas, such as nitrogen gas, and removing dissolved oxygen.

  Here, the extraction means may be column extraction or kneader extraction, but column extraction is more preferable.

  The concentration of non-polymer catechins in the solid content of the green tea extract thus obtained is preferably 24 to 40% by mass, more preferably 26 to 40% by mass, and particularly preferably 28 to 40% by mass.

  Moreover, the content (gallate body ratio) of the gallic acid ester in the non-polymer catechins in the obtained green tea extract is 40 to 62% by mass, further 45 to 60% by mass from the viewpoint of reducing bitterness and astringency. Especially 45-55 mass% is preferable. Here, the non-gallate body refers to catechin, gallocatechin, epicatechin, and epigallocatechin, and the gallate body refers to catechin gallate, gallocatechin gallate, epicatechin gallate, and epigallocatechin gallate.

  Since the obtained green tea extract contains non-polymer catechins at a high concentration and has reduced bitterness and astringency, it can be made into a packaged beverage as it is or by normal dilution.

Measurement of non-polymer catechins A beverage filtered through a filter (0.8 μm) is used with a high performance liquid chromatograph (model SCL-10AVP) manufactured by Shimadzu Corporation, and a packed column for liquid chromatography using an octadecyl group L-column TM ODS (4.6 mmφ × 250 mm: manufactured by Chemical Substance Evaluation Research Organization) was attached, and the gradient was performed 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 10 μL, and the UV detector wavelength was 280 nm. .

Column extraction A tea extract was produced using the extraction apparatus shown in FIG. Extraction water was heated by a pump 1 through a heat exchanger for heating ion-exchanged water, and passed from below to above the closed extraction column 3. The tea leaves 4 were charged between the tea leaf holding plate (lower) 6 and the tea leaf holding plate (upper) in the extraction column. The extract was recovered in the extract recovery tank 8 via the extract cooling exchanger 7.

Kneader Extraction Tea leaves were put into heated ion-exchanged water, stirred at 150 rpm for 5 minutes, filtered with suction, and cooled with ice.

Catechin extraction rate The total amount of non-polymer catechins contained in tea leaves was taken as 100%, and the amount of non-polymer catechins extracted under each condition was converted to obtain the catechin extraction rate.

Non-gallate body extraction rate / gallate body extraction rate The amount of non-gallate non-polymer catechin extracted in each condition was converted to 100% of the amount of non-gallate non-polymer catechin contained in tea leaves, and non-gallate body extraction Rate. Similarly, the amount of gallate non-polymer catechin was also converted and used as the gallate extraction rate. The non-gallate body extraction rate was divided by the gallate body extraction rate to obtain non-gallate body extraction rate / gallate body extraction rate. If this ratio is high, it can be said that bitter astringency is improved.

Example 1
Enzyme inactivation was carried out by steaming at 94 ° C. for 1.5 minutes using (Camellia sinensis) as green tea leaves. Subsequently, the CTC process (rotation speed 90rpm, 900rpm, 6 units continuous) was performed. Subsequently, it dried with the belt conveyor type dryer until the moisture content in a tea leaf became 5 mass% or less. Further, column extraction (magnification 10 times, extraction temperature 70 ° C., extraction processing time 2.4 minutes) was performed.
The concentration of non-polymer catechin in the obtained extract was 33% by mass in the solid content, and the content of gallic acid ester in the non-polymer catechins (hereinafter referred to as gallate body ratio) was 48% by mass. The catechin extraction rate was 61%, and the non-gallate extraction rate / gallate extraction rate was 1.43.

Example 2
The same procedure as in Example 1 was performed except that the extraction temperature was 90 ° C. The extract obtained had a non-polymer catechin concentration of 34% by mass in the solid content and a gallate content of 50% by mass. The catechin extraction rate was 65%, and the non-gallate body extraction rate / gallate extraction rate was 1.30.

Example 3
The same procedure as in Example 1 was performed except that the extraction magnification was 20 times and the extraction processing time was 4.8 minutes. The non-polymer catechin concentration of the obtained extract was 33% by mass in the solid content, and the gallate content was 51% by mass. The catechin extraction rate was 87%, and the non-gallate extraction rate / gallate extraction rate was 1.26.

Example 4
The same procedure as in Example 3 was performed except that the extraction temperature was 80 ° C. The extract obtained had a non-polymer catechin concentration of 33% by mass in the solid content and a gallate content of 52% by mass. The catechin extraction rate was 88%, and the non-gallate body extraction rate / gallate extraction rate was 1.22.

Example 5
The same procedure as in Example 1 was performed except that the extraction magnification was 30 times and the extraction processing time was 7.2 minutes. The extract obtained had a non-polymer catechin concentration of 33% by mass in the solid content and a gallate content of 53% by mass. The catechin extraction rate was 95%, and the non-gallate extraction rate / gallate extraction rate was 1.16.

Example 6
(Camellia sinensis) was used as green tea leaves, and enzyme inactivation was performed by steam heat treatment at 94 ° C. for 1.5 minutes. Subsequently, the CTC process (rotation speed 90rpm, 900rpm, 6 units continuous) was performed. Subsequently, it dried with the belt conveyor type dryer until the moisture content in tea leaves became 5 mass% or less. Furthermore, kneader extraction (25 times magnification, extraction temperature 70 ° C., extraction time 5 minutes) was performed.
The non-polymer catechin concentration of the obtained extract was 30% by mass in the solid content, and the gallate content was 51% by mass. The catechin extraction rate was 70%, and the non-gallate extraction rate / gallate extraction rate was 1.29.

Example 7
The same procedure as in Example 6 was performed except that the extraction temperature was 85 ° C. The non-polymer catechin concentration of the obtained extract was 31% by mass in the solid content, and the gallate content was 53%. The catechin extraction rate was 75%, and the non-gallate extraction rate / gallate extraction rate was 1.19.

Example 8
The extraction treatment time was 2.4 minutes, and the same procedure as in Example 3 was performed except that the composition of the used tea leaves was different. The extract obtained had a non-polymer catechin concentration of 31% by mass in the solid content and a gallate content of 55.8% by mass. The catechin extraction rate was 60.2%, and the non-gallate body extraction rate / gallate extraction rate was 1.48.

Example 9
The same operation as in Example 8 was performed except that the extraction temperature was 75 ° C. The extract obtained had a non-polymer catechin concentration of 31% by mass in the solid content and a gallate body ratio of 56.8% by mass. The catechin extraction rate was 65.2%, and the non-gallate extraction rate / gallate extraction rate was 1.42.

Example 10
The same operation as in Example 8 was performed except that the extraction magnification was 30 times and the extraction processing time was 3.6 minutes. The extract obtained had a non-polymer catechin concentration of 33% by mass in the solid content and a gallate content of 57.8% by mass. The catechin extraction rate was 74.7%, and the non-gallate body extraction rate / gallate extraction rate was 1.36.

Example 11
The same procedure as in Example 9 was performed except that the extraction magnification was 30 times and the extraction processing time was 3.6 minutes. The extract obtained had a non-polymer catechin concentration of 33% by mass in the solid content and a gallate content of 59.0% by mass. The catechin extraction rate was 77.7%, and the non-gallate body extraction rate / gallate extraction rate was 1.29.

Example 12
It carried out similarly to Example 6 except the composition of the used tea leaf differing. The extract obtained had a non-polymer catechin concentration of 31% by mass in the solid content and a gallate content of 58.2% by mass. The catechin extraction rate was 65.7%, and the non-gallate extraction rate / gallate extraction rate was 1.34.

Example 13
The same procedure as in Example 12 was performed except that the extraction temperature was 85 ° C. The extract obtained had a non-polymer catechin concentration of 33% by mass in the solid content and a gallate content of 61.1% by mass. The catechin extraction rate was 71.0%, and the non-gallate extraction rate / gallate extraction rate was 1.19.

Comparative Example 1
As green tea leaves, 2002 sencha was purchased and used for column extraction (extraction ratio 10 times, extraction temperature 70 ° C., extraction processing time 2.4 minutes).
The non-polymer catechin concentration of the obtained extract was 33% by mass in the solid content. The catechin extraction rate was 23%, and the non-gallate body extraction rate / gallate extraction rate was 1.25.

Comparative Example 2
The same operation as in Comparative Example 1 was performed except that the extraction magnification was 20 times and the extraction processing time was 4.8 minutes. The non-polymer catechin concentration of the obtained extract was 32% by mass in the solid content. The catechin extraction rate was 40%, and the non-gallate body extraction rate / gallate extraction rate was 1.18.

Comparative Example 3
The same operation as in Comparative Example 1 was performed except that the extraction magnification was 30 times and the extraction processing time was 7.2 minutes. The non-polymer catechin concentration of the obtained extract was 33% by mass in the solid content. The catechin extraction rate was 60%, and the non-gallate extraction rate / gallate extraction rate was 1.14.

Comparative Example 4
As green tea leaves, 2002 green tea was purchased and used, and kneader extraction (extraction ratio 25 times, extraction temperature 70 ° C., extraction time 5 minutes) was performed.
The non-polymer catechin concentration of the obtained extract was 30% by mass in the solid content. The catechin extraction rate was 64%, and the non-gallate extraction rate / gallate extraction rate was 1.08.

Comparative Example 5
The same procedure as in Example 2 was performed except that the extraction magnification was 40 times and the extraction processing time was 9.6 minutes. The non-polymer catechin concentration of the obtained extract was 33% by mass in the solid content. The catechin extraction rate was 100%, and the non-gallate extraction rate / gallate extraction rate was 1.00.

Comparative Example 6
The same procedure as in Example 6 was performed except that the extraction magnification was 40 times and the extraction temperature was 100 ° C. The non-polymer catechin concentration of the obtained extract was 28% by mass in the solid content. The catechin extraction rate was 65%, and the non-gallate extraction rate / gallate extraction rate was 1.04.

Comparative Example 7
The same procedure as in Example 6 was performed except that the extraction magnification was 100 times and the extraction temperature was 40 ° C. The non-polymer catechin concentration of the obtained extract was 22% by mass in the solid content. The catechin extraction rate was 33%, and the non-gallate extraction rate / gallate extraction rate was 2.09.

The obtained results are shown in Table 1. As a result, the green tea extract obtained by drying the enzyme-inactivated green tea leaves after CTC treatment and extracting at an extraction ratio of 30 or less has a high extraction rate of non-polymer catechins, and a non-gallate extraction rate / gallate extraction rate. Since the ratio is high, there is an effect of improving bitterness and astringency. On the other hand, in Comparative Examples 1 to 4 in which CTC treatment is not performed and in Comparative Example 7 in which CTC treatment is performed and the extraction temperature is 40 ° C. and the extraction magnification is 100 times, the extraction efficiency of catechins is low, or the non-gallate extraction rate / Lower gallate body extraction ratio, so the effect of improving bitterness and astringency is insufficient. Moreover, even if CTC processing is performed, Comparative Examples 5 and 6 having an extraction magnification of 30 or more have a high catechin extraction rate, but have a low ratio of non-gallate body extraction rate / gallate body extraction rate. Improvement effect is insufficient.

It is a figure which shows the outline of the extraction method using the closed column extractor of this invention.

Explanation of symbols

1 Pump 2 Exchanger for ion-exchange water heating 3 Closed extraction column 4 Tea leaf 5 Tea leaf holding plate (top)
6 Tea leaf holding plate (bottom)
7 Heat exchanger for cooling the extract 8 Extract recovery tank

Claims (3)

The enzyme-inactivated raw tea leaves are CTC-treated, dried until the water content is 20% by mass or less, and then with water at 60 to 100 ° C., the mass ratio of the extraction solvent to the tea leaves at the time of extraction is 5 to 30 times. A method for producing a green tea extract that is extracted under the above conditions.   The non-polymer catechin concentration in the solid content of the obtained green tea extract is 20 to 40% by mass, and 40 to 62% by mass of the non-polymer catechins is a gallate of catechins. Manufacturing method.   The production method according to claim 1 or 2, wherein the enzyme inactivation treatment is a treatment selected from steaming heat treatment, hot water immersion and kettle roasting treatment.

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