HK1167574B - Roasted oolong tea and tea drink using same - Google Patents

Description

Baked oolong tea and tea beverage using the same

Technical Field

The present invention relates to a baked oolong tea leaf obtained by baking oolong tea with direct fire and a tea beverage using the same, and more particularly to a packaged tea beverage in which deterioration of aroma during storage is suppressed.

Background

Tea is cultivated widely in various countries around the world, mainly in asia, and is widely drunk by people around the world as three major non-alcoholic hobby drinks in parallel with coffee and cocoa. Tea beverages have not only sugar-free but also health-maintaining functions such as antioxidant action and anticancer action, and their demand has increased significantly with the recent trend toward a hot state of health.

The tea can be roughly divided into unfermented tea (green tea), fully fermented tea (black tea) and semi-fermented tea (oolong tea, etc.). They are made from the leaves of tea trees (Camellia sinensis) belonging to the genus Camellia of the family Theaceae, but they form teas with distinct colors, aromas and tastes due to the difference in the processing method of the raw tea leaves, mainly the degree of oxidative fermentation.

One of the characteristics of oolong tea is the heavy floral aroma (floral aroma). Not only taste, i.e., taste felt by the tongue, but also smell, i.e., aroma felt by the nose, greatly contributes to the deliciousness of the semi-fermented tea beverage. The floral aroma is composed of terpene alcohols such as linalool, geraniol, and nerolidol, and aroma components such as jasmonate, methyl jasmonate, cis-jasmone, and indole.

In recent years, tea beverages containing a large amount of the above-mentioned floral components have been developed due to the improvement of preference. For example, patent document 1 discloses a method for producing an oolong tea beverage comprising a step of cold/warm water treatment of tea leaves and a step of hot water extraction, and describes that the oolong tea beverage obtained by the method contains nerolidol at a high concentration. Patent document 2 discloses a method for producing a semi-fermented tea beverage, which comprises an extraction step of extracting semi-fermented tea leaves using warm water having a temperature of 85 to 100 ℃ in which sodium ascorbate is dissolved, and describes that the semi-fermented tea beverage obtained by this method is a tea beverage that has an original aroma of semi-fermented tea, and the total aroma amount is 1.05 times as much as that of a tea beverage extracted with pure water.

Further, a method for improving the quality of oolong tea, which comprises subjecting oolong tea leaves to water-adding and heat-treating or simultaneously subjecting the oolong tea leaves to rough kneading treatment and then to heat-drying, has been reported (patent document 3). It is described that the oolong tea having good flavor and color tone and particularly suitable for cold water brewing can be obtained by this method.

On the other hand, roasted tea is widely known as one of green tea. The baked tea loses the original aroma of tea leaves due to baking, but can have fragrant baking aroma. Patent document 4 describes the following: when green tea leaves are baked using a roller baker, the unique refreshing aroma components (cis-3-hexenol) and the main components (linalool and nerolidol) of green tea are reduced, and aroma components (2, 5-dimethylpyrazine, trimethylpyrazine) generated by heating are generated.

Patent document 1 Japanese patent laid-open No. 2004-248672

Japanese patent application laid-open No. 2005-124499 of patent document 2

Patent document 3 Japanese patent laid-open publication No. Sho 61-234737

Japanese patent application laid-open No. 2001-286260 of patent document 4

Disclosure of Invention

In general, packaged tea beverages are produced from tea leaves as a main raw material, and in order to suppress deterioration in quality during heat sterilization treatment and long-term storage, sodium bicarbonate and ascorbic acid or a salt thereof are added to a tea extract, and the mixture is sterilized and filled. A packaged oolong tea beverage is also produced in the same manner, but only adding sodium bicarbonate, ascorbic acid, or the like cannot suppress deterioration in quality during heat sterilization treatment and long-term storage, and in particular, a method for solving the problem of reduction in floral aroma peculiar to oolong tea is not completely achieved. In addition, the methods described in the above prior art cannot selectively enhance the floral aroma, and the unpleasant aroma and bitter components of oolong tea are also extracted in large amounts, which may rather significantly deteriorate the quality when stored for a long period of time.

The present invention addresses the problem of providing a packaged oolong tea beverage that can maintain a floral aroma for a long period of time while suppressing degradation in the quality of the packaged oolong tea beverage during heat sterilization and long-term storage.

The present inventors have conducted intensive studies to solve the above problems and, as a result, have found that: baking oolong tea material under specific conditions to obtain baked oolong tea, extracting the baked oolong tea with hot water to obtain baked oolong tea extractive solution, and adding into a part of oolong tea beverage to reduce heating smell after heating sterilization treatment, reduce flavor deterioration, specifically oxidation deterioration smell during long-term storage, and maintain strong flower fragrance specific to oolong tea.

Further, contrary to the conventional idea that baking oolong tea under specific conditions causes a reduction in refreshing aroma peculiar to tea leaves and produces baked aroma, we surprisingly found that: the total amount of aroma components known as the floral aroma characteristic of oolong tea is increased, and the amount of 2, 4-heptadienal known as the unpleasant aroma which is easily deteriorated is decreased. Further, it was confirmed that a packaged oolong tea beverage in which the above-mentioned flower fragrance was maintained could be produced by using baked oolong tea in which the composition of aroma components was changed by the specific baking, and the present invention was completed.

That is, the present invention relates to the following.

[1] A method for manufacturing a packaged oolong tea beverage is characterized by comprising the following steps: baking oolong tea raw material with direct fire to obtain baked oolong tea; a step for obtaining a roasted oolong tea extract from the roasted oolong tea by hot water extraction; and a step of subjecting the roasted oolong tea extract to heat sterilization treatment.

[2] The process according to [1], wherein the oolong tea raw material is pulverized into a size of 3 to 10mm and the pulverized material is baked with direct fire.

[3] A baked oolong tea characterized by being obtained by baking an oolong tea raw material with direct fire.

According to the present invention, a packaged oolong tea beverage can be obtained which can maintain a rich floral aroma even when heat sterilization and long-term storage are performed, and which is suppressed in flavor deterioration during storage. The following advantages are also provided: the roasted oolong tea obtained by roasting an oolong tea raw material under specific conditions is useful for imparting a strong floral aroma and suppressing deterioration of flavor, and does not affect the natural flavor of the oolong tea beverage.

Detailed Description

(baked oolong tea)

Oolong tea is produced by sun-drying and shade-drying fresh leaves of oolong tea, subjecting the dried leaves to oxidative fermentation by shaking the leaves in a bamboo cage or the like, stopping the fermentation by heating the leaves in a pot when the oxidative fermentation has progressed to about 30% to 70%, and drying the raw tea subjected to rolling or the like to produce fine tea. The baked oolong tea of the present invention is oolong tea obtained by baking raw oolong tea and/or refined oolong tea with direct fire. As the fresh leaves of oolong tea, any tea tree (c. senensis) of the genus camellia of the family theaceae can be used, and as one of preferable embodiments, for example, var. senensis (chinese species) can be used. As the oolong tea, commercially available oolong tea (fine tea) such as black oolong tea, puffed tea, hastelling tea, Wuyi narcissus, Wuyi Qizhong, Guangdong Fenghuangxi narcissus, Tieguanyin, Huangjingui, Cai-chun, oolong, Taiwan frozen roof, heaping tea, and bottle gourd heap tea can be used.

The raw material may be any of leaves, stems, or a mixture thereof, and preferably stems are used as the fresh leaves. Although baking flavor such as pyrazine is generated by baking, bitterness of catechins and/or caffeine is increased in an additive or synergistic manner by this pyrazine. From the viewpoint of using roasted oolong tea so as not to affect the natural flavor of the underlying oolong tea beverage and to suppress deterioration in quality due to heat sterilization and long-term storage, stems with low contents of catechins and caffeine are preferably used.

The baked oolong tea of the present invention is characterized in that a roller baker is used for baking with direct fire. By baking with direct fire using a roller baking machine, the total amount of aroma components (linalool, geraniol, nerolidol, jasmone, methyl jasmonate, cis-jasmone, indole) known as the floral aroma unique to oolong tea increases, and 2, 4-heptadienal known as an unpleasant aroma that is easily deteriorated decreases. The roller baker may be a continuous baker or a batch baker. Among the roller dryers, a rotary roller far infrared dryer can be cited as one of preferable modes.

The conditions of the direct fire baking depend on the quality (such as moisture content) and the input amount of the raw materials, generally, the temperature (the set temperature of the baking machine) is 150-250 ℃, preferably 160-180 ℃, the baking time is 3-10 minutes, preferably 5-9 minutes, and the temperature of the tea product at the outlet is 120-180 ℃.

When baking is performed, if oolong tea is ground to a size of about 3 to 10mm in advance, uniform baking is easily performed. The roasting machine is not limited at all, but from the viewpoint of easy uniform roasting, a rotary drum type far infrared roasting machine is preferably used. As described above, the baked oolong tea of the present invention is obtained by subjecting raw tea to the direct-fire baking treatment, but if the raw tea is dried in advance by a drum dryer, a microwave dryer, or the like so that the moisture content in the tea leaves becomes about 5% or less, the tea leaves are baked uniformly in the direct-fire baking, which is preferable.

The baked oolong tea thus obtained by drying the raw tea and baking the same on a roller increased the total floral scent by about 1.1 times before and after baking. When green tea is used as tea leaves, the above-mentioned floral components are greatly reduced, and therefore, the increase in floral components is considered to be a particular phenomenon caused by the combination of oolong tea and direct fire baking.

In flower fragrance, particularly, the cis-jasmone, the jasmone lactone and the methyl jasmonate are obviously increased, the cis-jasmone is increased by more than 1.5 times, and the jasmone lactone and the methyl jasmonate are increased by more than 2 times. In addition, the following features are provided: linalool is an aroma component that is not increased by baking other than conventional extraction methods and direct fire baking, but is increased by about 1.3 times when direct fire baking is performed. Further, the following features are provided: indole in floral aroma is known as a cause of formation of a heat smell during heat sterilization (see japanese patent application laid-open No. 2004-147606, claim 2), but in the baked oolong tea obtained by direct fire baking of the present invention, the indole is reduced to about 0.7 times.

That is, the direct fire baking of the present invention changes the composition of the floral aroma of oolong tea. Specifically, the total amount of fragrance components of the flower fragrance (a) other than indole (linalool, geraniol, nerolidol, jasmone, methyl jasmonate, cis-jasmone) (a1) was about 1.2 times that before baking, and the ratio ((a1)/(a2)) of the flower fragrance (a1) to indole (a2) was changed from 2.9 before baking to 5.1 after baking. Further, when the direct fire baking of the present invention is performed, the easily-deteriorated aroma component 2, 4-heptadienal (B) contained in the oolong tea is reduced to about 0.65 times.

In the baked oolong tea of the present invention, the ratio ((a1)/(a2+ B)) of the aroma component (a1) having a pleasant oolong fragrance even after heat sterilization to the aroma component (a2, B) which is easily deteriorated to form an offensive odor during heating and storage is 1 or more, preferably 1.2 or more, and more preferably 1.5 or more. By using oolong tea having a composition within this range and adding the extract to a tea beverage, a tea beverage can be produced which can maintain a strong floral aroma even after heat sterilization and long-term storage and which is suppressed in deterioration of quality.

(Container-packed oolong tea beverage)

The packaged oolong tea beverage of the present invention is characterized by using the above-mentioned baked oolong tea. Namely, comprising: baking oolong tea raw material with direct fire to obtain baked oolong tea; a step for obtaining a roasted oolong tea extract from the roasted oolong tea by hot water extraction; and a step of subjecting the roasted oolong tea extract to heat sterilization treatment.

The extraction of the baked oolong tea is carried out for 1 to 20 minutes, preferably 2 to 15 minutes, and particularly preferably 3 to 10 minutes, using hot water at a temperature of 70 ℃ or higher, preferably 80 to 95 ℃, and particularly preferably 85 to 95 ℃. If the extraction temperature is too low, the aroma components, particularly the floral aroma, of the baked oolong tea cannot be extracted well, and if the extraction temperature is too high or the extraction time is too long, pyrazines and other bitter components of the baked oolong tea are also extracted in a large amount. The extraction may be carried out by stirring, or an organic acid or organic acid salt such as sodium ascorbate may be added to the extraction solvent (hot water). The mixing ratio of the baked oolong tea and the extraction solvent (hot water) is preferably about 1: 15 to 1: 100.

In the tea beverage of the present invention, the total amount of the extract of roasted oolong tea may be used as the tea beverage, but the flavor of roasted oolong tea is affected by the aroma of roasting, and therefore, it is preferable to add the extract of roasted oolong tea to a part of the tea beverage. In this case, the roasted oolong tea extract and the oolong tea extract serving as the base of the tea beverage may be mixed after separately preparing them, or the roasted oolong tea may be mixed with the extraction material (oolong tea leaves) and then subjected to hot water extraction. The oolong tea used as the base may be any of black oolong, puffed tea, hasten tea, Wuyi narcissus, Wuyi Qizhong, Guangdong Fenghuangxin, Tieguanyin, Huangjingui, Caichong, oolong, Taiwan frozen top, piled tea, and calabash piled tea. The mixing ratio of the roasted oolong tea and the basic oolong tea leaves or the roasted oolong tea extract and the basic oolong tea extract may be appropriately adjusted depending on the type of the basic oolong tea, the extraction temperature, the flavor of the target tea beverage, and the like, and usually, the roasted oolong tea (or the roasted oolong tea extract) is contained in an amount of about 1 to 100% by weight, preferably about 1.5 to 50% by weight, based on the total amount of the extraction raw materials (or the total amount of the tea beverage).

Subsequently, the obtained extract was cooled and then filtered. As a method of filtration, a centrifugal separator, a metal mesh, flannel, diatomaceous earth, a ceramic membrane, or the like can be used. Optionally adding ascorbic acid to the filtrate to obtain a mixed solution, and heat sterilizing. By adding ascorbic acids, the deterioration of the quality of the oolong tea beverage during heat sterilization and long-term storage can be further suppressed. Ascorbic acids are added to the solution at a concentration of 100ppm or more, preferably 300ppm or more, and more preferably 400ppm or more. The ascorbic acids in the present specification mean 1 or 2 or more selected from ascorbic acids, isomers thereof, derivatives thereof, and salts thereof.

The heat sterilization treatment can be performed by a known method. For example, when a canned beverage is prepared, a predetermined amount of the above-mentioned preparation is filled in a can, and the can is sterilized in a sterilizer (for example, 1.2mmHg, 121 ℃ C., 7 minutes). When the product is formed into PET bottles, paper packages, or bottled beverages, for example, UHT sterilization is performed by maintaining the product at 120 to 150 ℃ for 1 to several tens of seconds.

The obtained oolong tea beverage has rich fragrance of baked oolong tea, and complements each other with pyrazine fragrance, and has more mellow and heavy fragrance. Therefore, the packaged beverage can maintain the floral aroma peculiar to oolong tea for a long period of time (1 year, preferably 6 months or longer, and more preferably 4 months or longer) without adding a perfume.

Examples

The details of the present invention will be described below with reference to experimental examples and examples, but the present invention is not limited thereto.

Example 1: manufacture of baked oolong tea

The stem part of the raw tea of oolong tea (narcissus species) was recovered, crushed to a size of 3 to 10mm, and hot-air dried (ordinary heating) at 120 ℃ for 45 minutes. The moisture content after drying is 5% or less. Then, the dried stem tea (100g) was put into a roller roaster heated to about 180 ℃ in its internal temperature, and roasted for about 5 minutes. And finally taking out the tea product when the temperature of the tea product reaches 145 ℃, cooling and preparing the baked oolong tea.

Example 2: roasted oolong tea extract

10g of the baked oolong tea obtained in example 1 was extracted with 1L of hot water (90 ℃ C.) for 5 minutes. Further, the same extraction was carried out using the stem tea not subjected to the direct fire roasting treatment of example 1, that is, the stem tea (non-roasted) obtained by recovering the stem tea portion from the raw tea and the stem tea obtained by hot air drying the stem tea (ordinary heating). The aroma components of the obtained extract were analyzed by stirring and adsorbing them with a Twister (stirring Bar obtained by coating polydimethylsiloxane on a stirring Bar; manufactured by GERSTEL Co., Ltd.) by SBSE (Stir Bar Sorptive extraction: stirring Bar adsorption extraction) method. The analysis conditions are as follows.

(adjustment of analytical samples)

Sample (weighing): 10g

Adsorption temperature: 25 ℃ (room temperature)

Adsorption time: 30 minutes

(analytical instruments and conditions)

TDS conditions(Thermo Desorption System, thermal Desorption apparatus)

The desorption temperature is 20 ℃ (0.5min) to 200 ℃ (60 ℃/min, keeping for 4.5min)

Without diversion

Instrument GERSTEL TDS2

GC-MS conditions

Column Inert Cap WAX-HT (60m 0.25mm I.D., Film 0.25 μm)

Column temperature 70 deg.C (5min) -260 deg.C (3 deg.C/min)

The sample injection temperature is-150 ℃ to 240 ℃ (12 ℃/sec, 5min of holding)

Flow rate 1.9mL/min

Without shunting for 1min

Instrument Agilent GC 6890, MSD 5973N

The results are shown in Table 1. As can be seen from table 1, when the direct fire baking was performed, the total amount of floral aromas (linalool, geraniol, nerolidol, jasmone, methyl jasmonate, cis-jasmone, indole) increased to 1.1 times. In particular, the total amount of floral scents (a1) other than indole was increased by 1.24 times, wherein the increase in cis-jasmone, jasmone lactone and methyl jasmonate was significant, the increase in cis-jasmone was 1.5 times or more, and the increase in jasmone and methyl jasmonate was 2 times or more. Linalool did not increase at all in the case of ordinary drying (heating), but increased by a factor of about 1.3 by baking with direct fire.

On the other hand, by the direct fire baking, indole (A2) was reduced to about 0.7 times, and the total amount of 2, 4-heptadienal (B) was reduced to about 0.65 times.

The ratio of floral aroma (a1) ((a1)/(a2)) to indole (a2) was calculated to be 2.9 in the case of non-baked versus 4.1 in the case of ordinary drying (heating) and 5.1 in the case of direct fire baking, with the proportion of pleasant floral aroma increasing by baking, in particular direct fire baking. Further, the ratio ((a1)/(a2+ B)) of the aroma component (a1) having a pleasant oolong tea aroma even after heat sterilization to the aroma component (a2, B) which easily deteriorates during heating and storage to form an offensive odor was calculated to be 0.86 in the case of non-baking, 0.94 in the case of ordinary drying (heating), and 1.60 in the case of direct-fire baking.

[ Table 1]

The lower () indicates an increase rate when the non-baking is 1.

Subsequently, sensory evaluation was performed by 4 judges using a normal dried (heated) oolong tea extract and a baked oolong tea extract of the present invention obtained by baking with direct fire. As a result, the extract of ordinary dried (heated) oolong tea has a strong fragrance but a weak top note, and the extract of baked oolong tea of the present invention has a fragrant top note and a sweet taste (i.e., the top note and the end note are enhanced).

Top note (also called top note) is one of aroma divided into 3 parts relatively according to volatility, and is usually composed of a low-boiling point and high-volatility substance, and is an aroma component that determines the first impression of a beverage. Here, the fragrance felt by the nose before drinking and the fragrance felt from the nostrils at the moment of being taken into the mouth are referred to as "top notes". The top note (also called aftertaste) is a component that is related to the depth of the aroma and taste, and is generally composed of a substance having a low volatility and a high boiling point, and here, it refers to the aroma that is perceived as taste when drinking.

Example 3 tea beverage in Container

1g of the baked oolong tea produced in example 1 and 59g of mixed tea leaves of narcissus and color variety were mixed to prepare an extraction material. Extracting with hot water (1.2L) at 90 deg.C under stirring for 5min, recovering the extractive solution, coarse filtering, cooling to below 20 deg.C, filtering by centrifugation, adding ascorbic acid (300 ppm of final product), and adding sodium bicarbonate to adjust the pH of the tea beverage to about 6.0. Adding water to 5L to obtain a concoction, sterilizing at 140 deg.C for 15 s, and filling into a can at 82 deg.C to obtain oolong tea beverage (beverage containing baked oolong tea). For comparison, a tea beverage (ordinary oolong tea beverage) was similarly prepared using a mixed tea leaf (60g) without addition of roasted oolong tea, i.e., narcissus and color seeds. The flavor of the tea beverage immediately after preparation and after storage was evaluated organoleptically.

Compared with the flavor immediately after preparation, the beverage added with the baked oolong tea is an oolong tea beverage with enhanced top note, mellow taste and sweet taste, harmonious top note and tail note, balanced whole, freshness and good flavor. The sensory evaluation results of the flavor of the tea beverage after storage are shown in table 2. As is clear from table 2, the packaged oolong tea beverage containing the roasted oolong tea extract showed good flavor at any temperature band, as compared with the non-added (ordinary oolong tea beverage).

The above results indicate that the packaged oolong tea beverage containing the roasted oolong tea extract has enhanced floral aroma, is refreshing, maintains good aroma even after long-term storage, suppresses the generation of oxidative deterioration odor during storage, and maintains commercial value even after long-term storage for up to 1 year.

[ Table 2]

Score with 5 full points. No commodity value under 3 points

Claims (5)

1. A method for manufacturing a packaged oolong tea beverage is characterized by comprising the following steps:

baking oolong tea raw material with direct fire to obtain baked oolong tea;

a step for obtaining a roasted oolong tea extract from the roasted oolong tea by hot water extraction; and the number of the first and second groups,

heating and sterilizing the roasted oolong tea extract,

wherein, in the flower fragrance of the oolong tea baked with direct fire, the ratio ((A1)/(A2+ B)) of the fragrance component (A1) having a pleasant flower fragrance of oolong tea after heat sterilization to the fragrance component (A2, B) which is easily deteriorated during heating and storage to form an offensive odor is 1 or more,

wherein A1 is the total amount of linalool, geraniol, nerolidol, jasmone, methyl jasmonate and cis-jasmone; a2 is the amount of indole; b is the amount of 2, 4-heptadienal.

2. The process according to claim 1, wherein the ratio of ((A1)/(A2+ B)) is 1.2 or more.

3. The process according to claim 2, wherein the ratio of ((A1)/(A2+ B)) is 1.5 or more.

4. The method according to any one of claims 1 to 3, wherein the oolong tea raw material is pulverized into a size of 3 to 10mm and baked with direct fire.

5. A baked oolong tea obtained by the production method according to any one of claims 1 to 4.