JP6535077B2 - Method of producing concentrated tea extract and extract by freeze concentration method - Google Patents

Description

  The present invention relates to a concentrated tea extract maintaining a rich flavor and a method for producing an extract, wherein the tea extract is adjusted to a Brix of 7.3% or more by addition of dextrin and then freeze-concentrated.

As a method of concentrating the tea extract, concentration by a rotary vacuum evaporator using evaporation by heating or reduced pressure (flash evaporator concentration), concentration by a plate type concentrator (PHE concentration), concentration by a centrifugal thin film vacuum evaporator (TFE concentration), concentration by reverse osmosis membrane or ultrafiltration membrane (RO membrane or UF membrane concentration), freeze concentration (FC), etc. are known as prior art.
The concentration by evaporation is such that the aroma component is easily denatured / decomposed / oxidized by heating, so that deterioration of the flavor, composition change of the aroma component, and significant reduction of the aroma component accompanying evaporation are inevitable. Also in the method of concentration with a membrane, the aroma component is adsorbed to the membrane to change the composition of the aroma component, or it is discharged together with the permeate to impair the flavor.

With respect to these concentration methods, freeze concentration involves cooling the input solution, converting the water content of the solution into pure ice crystals, and separating the ice crystals from the solution. Can be obtained, so it is possible to obtain a concentrate which retains the flavor balance before concentration and the amount of aroma components.
However, when the tea extract is concentrated by freeze concentration, there is a problem that the formation of ice containing tea solids rapidly occurs and it can not be separated into pure ice crystals and a concentrate.

In order to solve the above-mentioned problems, Patent Document 1 is connected with a separation method in the form of ultrafiltration before the freeze concentration step, which causes, for example, an increase in the viscosity of the concentrate during freeze concentration such as polymer molecules. There is disclosed a method of removing freeze concentration method limiting factors that also reduces the ability of this concentration step.

In Patent Document 2, the formation of tea cream makes it possible to rapidly form ice crystals by tannizing the tea extract in advance, which has been considered unsuitable for the conventional freeze concentration method, and rapidly freezing it. Methods are disclosed.

According to the freeze concentration method described in Patent Document 3 that the concentration efficiency is poor for green tea and is not practical, the concentration efficiency of freeze concentration is practically achieved by previously removing tannin which is a bitter component. A method of raising

However, all the techniques described in the above-mentioned documents make it essential to remove or decompose the components of the tea extract, and the adverse effect on the flavor of the concentrated tea extract after freeze concentration could not be avoided.

Therefore, the provision of a method for efficiently producing a concentrated tea extract having a flavor equivalent to that of the tea extract before concentration has been sought.

JP-A-56-089802 Japanese Patent Application Publication No. 05-328901 Patent document 1: JP-A-2002-238458

Freeze concentration can prepare a concentrated solution with excellent flavor. However, when the tea extract is concentrated by the freeze concentration method, the formation of ice containing tea solids rapidly occurs, and there is a problem that it can not be separated into pure ice crystals and a concentrate.

Therefore, an object of the present invention is to provide a freeze concentration method for efficiently producing a concentrated flavored tea extract.

The present inventor examined the reason why the tea extract can not be normally concentrated in the freeze concentration method, but the concentration of the tea extract obtained by general industrial methods such as extraction with doubs, countercurrent extraction, shower type extraction is Brix 6 It became clear that the cause is as low as less than 0% (about 1.0 to 6.0%).
When TFE concentration or RO membrane concentration was attempted as a preconcentration step for the tea extract to increase Brix of the tea extract prior to freeze concentration, freeze concentration was successful, but in this case, in the preconcentration step The loss of flavor, the change in composition of aroma components and the reduction of aroma amount are inevitable, the need for equipping a preconcentrator, and the time loss required for the preconcentration step have become problems.
Therefore, as a result of intensive efforts, when the extract of teas was adjusted to Brix 7.3% or more by the addition of dextrin, it was possible to unexpectedly freeze and concentrate the tea extract which does not require the pre-concentration step . Therefore, according to the present production method, the present invention has been achieved with the finding that high-quality concentrated tea extracts having excellent flavor can be efficiently obtained, and the present invention has been completed.

That is, the invention according to the scope of the present invention is a method for producing a concentrated tea extract , which comprises freezing and concentrating the tea extract after adjusting the tea extract to 13.7% or more and 20.0% or less by adding dextrin. The present invention relates to a method for producing a concentrated tea extract, wherein the amount of the additive is 2.0 to 3.5 parts by weight with respect to 1 part by weight of tea solids .

  According to the present invention, it is possible to obtain an efficient freeze concentration method in which loss of flavor is suppressed, and a concentrated tea extract in which loss of flavor is suppressed.

  The present invention is to concentrate by freeze concentration a tea extract whose Brix has been adjusted to 7.3% or more by the addition of dextrin.

Tea extract refers to the fresh leaves and stems of tea trees (Camellia sinensis var. Sinensis or Camellia sinensis var. Assamica, or hybrids thereof) or tea leaves produced using these as primary raw materials (eg, Sencha, Gyokuro, covered tea) Bancha, potted green tea and other infermented tea, Jasmine tea and other flower tea that transferred the smell of flowers to infermented tea, weakly fermented tea such as white tea, semi-fermented tea such as oolong tea, fermented tea such as black tea, and puar tea Etc. means the liquid which extracted the post-fermented tea etc. as a raw material or its part. In addition to brown leaves, brown rice, barley, wheat, pigeons, corn, amaranthus, quinoa, nanban kibi, mozuku, licorice, lotus, persimmon, pine, plantain, rosemary, persimmon, ketsumeishi, soy bean, kelp, ganoderma, kelp, It is obtained by using leaves, stems, roots, fruits, seeds, etc. in combination with various plants such as persimmon, sesame, safflower, cuttlefish, buckwheat, guava, aloe, gymnema, toboko, dokudami, chicory, evening primrose, loquat etc. Also good.

Examples of the method for extracting tea include known methods such as a batch type extraction method using a kneader or an extraction tank, a column type extraction method using an extraction tower, and a shower type extraction method. The extraction conditions are appropriately selected according to the type of raw material tea leaves, the type of extractor, flavor, etc. For example, 3 to 50 parts by weight of an extraction solvent may be used with respect to 1 part by weight of raw material tea leaves. 30 parts by weight is preferable in terms of extraction efficiency, production cost and quality. It is preferable to use water, warm water, or hot water as the extraction solvent since there is no safety problem. The extraction temperature is not particularly limited, but it is preferably 50 to 90 ° C., and more preferably 60 to 80 ° C. for unfermented tea and weakly fermented tea. For semi-fermented tea, fermented tea and post-fermented tea, 60 to 100 ° C. is preferable, and 80 to 100 ° C. is more preferable. The extraction time depends on the amount of extraction solvent and the extraction temperature, but it is preferably 30 seconds to 6 hours, preferably 3 minutes to 3 hours, and more preferably 4 minutes to 1 hour. At the time of extraction, stirring is carried out as needed under normal pressure, pressure or reduced pressure, and filtration or centrifugation such as a filter press using a cartridge filter, filter cloth, filter plate, filter paper, filter aid and the like after the above extraction step It is recommended that a tea extract be obtained by solid-liquid separation by separation or the like. In addition, in the extraction step, an antioxidant may be added to suppress oxidation of the tea extract. Antioxidants include ascorbic acid, erythorbic acid or metal salts thereof which are recognized as food additives.

The concentrated tea extract refers to a tea extract from which a part of the water of the tea extract has been removed and which is concentrated by the concentration treatment.
The degree of concentration is not particularly limited, but the Brix of the concentrated tea extract is preferably 20.0% or more. Brix 25.0% or more is more preferable, and 30.0% or more is the most preferable.
In addition, Brix in this invention represents the numerical value obtained by the measurement by a vibration type density gravimeter (Kyoto electronic industry: DA-300).

Freeze concentration is a low temperature (under freezing point) and closed system, and it is characterized by the fact that the loss of physicochemical denaturation of the raw material and the aroma component due to the temperature rise is small by the principle that water is taken out from the mother liquor in the form of ice. It is. Therefore, the residual ratio of low boiling point and low molecular weight components is extremely high, and it is possible to produce a high quality concentrate having the same quality as the raw material. In the freeze concentration of the present invention, conditions are not particularly limited, and a commercially available general freeze concentration device can be used as it is, but in the case of Glenco, for example, the following three devices can be broadly divided. It is configured.
1) Surface scraping type heat exchanger (Scraped Surface Heat Exchan
ger)
2) Recrystallizer
3) Washable separation column (wash column)
Then, a surface scraping type heat exchanger is used to form a core of ice, and the ice is grown by a recrystallization apparatus, and the ice and the concentrate are separated by a washing type separation column.

It is a requirement for efficient freeze concentration that the tea extract used for freeze concentration has a freezing point lower than that of pure water. When the freezing point difference (Δt ° C.) with pure water is 0.4 ° C. or more, it is preferable because ice crystals are efficiently formed. If Δt is less than 0.4 ° C., the formation of ice containing tea solids rapidly occurs, and the whole liquid becomes an ice block, so that it can not be separated into pure ice crystals and a concentrated liquid. That is, concentration can not be achieved if Δt is small. Therefore, in order to increase Δt, it is necessary to increase the Brix of the liquid to be subjected to freeze concentration.

Dextrin refers to gelatinized starch or starch which is decomposed by an acid such as α-amylase or hydrochloric acid or oxalic acid while gelatinizing, and includes maltodextrin, cyclodextrin, branched dextrin and the like.
In general, a starch hydrolyzate is expressed in terms of dextrose equivalent (DE) as the degree of degradation, and one in which DE is degraded to about 5 to 21 is called maltodextrin. In the present invention, it is preferable to use maltodextrin which is DE 5 to 21 in view of price and no adverse effect on flavor, and DE 16 to 21 is more preferable from the viewpoint of storage stability.

Dextrin may be added to the tea extract at any stage of the manufacturing process prior to the freeze concentration step, but it is better to add dextrin to the aqueous solvent to perform extraction and concentration as the aroma component in the process. It is preferable because loss of flavor due to denaturation or loss can be suppressed.

Dextrin may be added in combination with other carbohydrates. For example, it includes monosaccharides, complex polysaccharides, oligosaccharides, sugar alcohols or mixtures thereof. Examples of monosaccharides are tetrose, pentose, hexose and ketohexose. An example of a hexose is an aldohexose such as glucose known as glucose. Fructose, known as fructose, is a ketohexose. As monosaccharides, mixed monosaccharides such as corn syrup, high fructose corn syrup, fructose glucose syrup, glucose fructose syrup, agape extract and honey can also be used. In addition, polyhydric alcohols such as glycerol can also be used in the present invention.

The Brix of the tea extract adjusted by the addition of dextrin is preferably 7.3% or more. Brix 12.0% or more is more preferable. 15.0% or more is more preferable. When the Brix of the tea extract is 7.3% or more, when the freeze concentration is started, pure ice crystals are easily generated and separated from the tea extract, so that the concentration can be efficiently started. If the Brix is less than 7.3%, the whole tea extract freezes and pure ice crystals can not be produced, so that freeze concentration can not be started. If Brix exceeds 45.0% due to dextrin, the viscosity may be high at low temperatures, which may be inconvenient for freeze concentration processing.

The addition amount of dextrin is not particularly limited as long as it is an amount to adjust Brix of the tea extract to a concentration that can be concentrated, but it is 0.4 to 4.0 parts by weight with respect to 1 part by weight of tea solids. Is preferred. 0.6 to 3.0 parts by weight is more preferable, and 0.8 to 2.0 parts by weight is further preferable. If the amount of dextrin added is less than 0.4 parts by weight depending on the type of tea and extraction conditions, Brix will not be sufficiently enhanced, and if it exceeds 4.0 parts by weight, the effect of the unique flavor of dextrin itself will be affected In some cases, the flavor of the tea extract may be inferior to that of starch.
The solid content of tea in the present invention is a value derived from Brix of a tea extract to which no additive such as dextrin is added according to the formula (Brix × liquid amount / 100).

The tea extract may be treated with tannase prior to the concentration step. By treating the tea extract with tannase, it is possible to prevent the occurrence of creamdown in the freeze-concentrator, and to prevent mechanical failure such as clogging of piping, valve, liquid feed pump, malfunction, clogging of filter, etc. By facilitating the separation of the ice crystals and the concentrate, it contributes to the concentration maintaining the component ratio of the tea extract before and after concentration, enabling concentration with high concentration, and raising the washing efficiency of ice crystals to produce It is possible to improve the efficiency and to prevent the decrease in yield.

  In the freeze concentration step, a concentrated tea extract can be continuously produced by continuously or intermittently feeding the tea extract into the freeze concentration apparatus. The concentrated tea extract excellent in flavor can be continuously manufactured by adding the tea extract adjusted to Brix 7.3% or more with dextrin. Moreover, generation | occurrence | production of the cream down in a freeze concentration apparatus can be prevented by using the tea extract which added dextrin continuously, and problems, such as clogging of a filter, can be prevented.

The concentrated tea extract of the present invention obtained by the above-described method can be used as it is in a liquid state, but if necessary, it should be put into a powder or block tea extract state by adopting an appropriate drying treatment. You can also. In the drying process, spray drying, vacuum drying, lyophilization, etc. may be mentioned, and in terms of cost, spray drying is preferable. From the viewpoint of aroma component retention, the tea extract is frozen and ice is sublimed by reduced pressure to remove water. Lyophilization is preferred.

The concentrated tea extract and tea extract can be used to produce food and drink such as tea beverages. Concentrated tea extract and tea extract have an advantage that transportation cost and storage cost can be easily reduced rather than transporting or storing the tea extract containing a large amount of water as it is, mainly for the purpose However, it can also be used by adding it to other food and drink as it is. The tea beverage can be commercialized by performing sterilization treatment or the like after reducing (diluting) the concentrated tea extract and the tea extract to a concentration suitable for drinking.

According to the embodiment of the present invention, it is possible to provide an extract of teas in which the reduction of the aroma component is suppressed since no other concentration step is required as a pretreatment for freeze concentration. Therefore, the concentrated tea extract or the tea extract subjected to the freeze concentration process of the present invention can be used to provide food and drink having excellent flavor. Examples of food and drink include beverages such as tea beverages, sports beverages, carbonated beverages, fruit juice beverages, milk beverages, liquors, powdered beverages and the like; ice confections such as ice creams, sherbets, ice candy and the like; Foods and beverages to which various functional properties such as chewing gums, chocolates, breads and the like; various snacks and the like can be provided.

The present invention will be described in more detail by way of the following examples. However, the present invention is not limited to this.

<Production of black tea extract>
After extracting 10 kg of black tea leaves (Mitsui Norin: 90% dibrane + 10% blend) with 90 liters of ion-exchanged water at 85 ° C for 40 minutes, 50 mesh filtration and centrifugation were performed to obtain 55 kg of Brix 5.3% black tea extract .

<Concentration of black tea extract>
Comparative product 1 <TFE concentration>
The same steps as in Example 1 were repeated three times to obtain 163 kg of a Brix 5.3% black tea extract.
The extract is concentrated by a centrifugal thin film concentrator (Ogawara Seisakusho: CEP-5S) at a liquid temperature of 28 to 32 ° C, a heating temperature of 76 to 84 ° C, a rotation speed of 790 rpm, and a vacuum degree of 4 to 5 kPa. 20 kg of a% concentrate was obtained.

Comparative product 2 <RO membrane concentration>
The same steps as in Example 1 were repeated twice to obtain 110 kg of Brix 5.4% black tea extract.
This extract was concentrated by a reverse osmosis membrane (Nitto Denko: NTR-759 HG) at a liquid temperature of 35 ° C., a pressure of 2.0 MPa, and a circulation flow rate of 10 L / hr to obtain 15 kg of a Brix 29.7% concentrate .

Comparison product 3 <FC>
The same steps as in Example 1 were repeated four times to obtain 220 kg of a Brix 5.2% black tea extract.
The condition that the difference between the temperature of the extract in the device and the temperature of the cooling solvent becomes 5 to 7 ° C. by the freeze concentrator (GEA Niro: NFC-W6) (extract temperature-1.1 ° C., the temperature of the cooling solvent) An attempt was made to concentrate at -7.1 ° C). However, because the Brix of the extract was low, ice crystals were not generated and concentration was not possible.

Comparative product 4 <TFE preconcentration → FC>
The same steps as in Example 1 were repeated six times to obtain 338 kg of a Brix 5.2% black tea extract.
The extract is concentrated by a centrifugal thin film concentrator (Ogawara Seisakusho: CEP-5S) at a liquid temperature of 28 to 33 ° C, a heating temperature of 76 to 80 ° C, a rotation speed of 803 rpm, and a vacuum degree of 4 to 5 kPa. It obtained 158 kg of the concentrate which had been raised to 6%.
Next, this concentrate was used as an initial input solution and concentration was started with a freeze concentrator (GEA Niro: NFC-W6). The additional solution after preparation of the ice crystals used was 325 kg of a Brix 5.2% extract obtained by repeating the same steps as in Example 1 six times. The operation was performed so that the ratio of ice crystals in the apparatus: 30 to 50%, under the condition that the difference between the temperature of the extract liquid and the temperature of the cooling solvent in the apparatus is 5 to 7 ° C. This concentration yielded 70 kg of a 29.6% Brix concentrate.

Comparative product 5 <RO membrane preconcentration → FC>
The same steps as in Example 1 were repeated six times to obtain 331 kg of a Brix 5.2% black tea extract.
The extract was concentrated with a reverse osmosis membrane (manufactured by Nitto Denko: NTR-759 HG, liquid temperature 35 ° C., pressure 2.0 MPa, circulation flow rate 10 L / hr) to obtain 150 kg of a 10.9% Brix concentrate.
Next, this concentrate was used as an initial input solution and concentration was started with a freeze concentrator (GEA Niro: NFC-W6). The additional solution after preparation of the ice crystals used was 340 kg of a Brix 5.3% extract obtained by repeating the same steps as in Example 1 six times. The operation of the freeze concentrator was carried out so that the ratio of in-apparatus ice crystals was 30 to 50% under the condition that the difference between the temperature of the extract solution in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. This concentration yielded 80 kg of a Brix 30.3% concentrate.

<Concentration of black tea extract added with dextrin>
Comparative product 6 <TFE concentration>
The same steps as in Example 1 were repeated twice to obtain 111 kg of a Brix 5.3% black tea extract. To this extract, maltodextrin of DE 17-21 (Sanei saccharification: NSD 700) was added twice as much as the solid content of tea, stirred and dissolved. The solution had a Brix of 14.0% and a weight of 123 kg. This solution is concentrated by a centrifugal thin film concentrator (Ogawara Mfg. Co., Ltd .: CEP-5S) at a solution temperature of 30 to 32 ° C, a heating temperature of 76 to 80 ° C, a rotation speed of 803 rpm, and a vacuum degree of 4 to 5 kPa. 40 kg of a concentrated solution of

Comparative product 7 <RO membrane concentration>
The same steps as in Example 1 were repeated twice to obtain 116 kg of a Brix 5.2% black tea extract. To this extract, maltodextrin of DE 17-21 (Sanei saccharification: NSD 700) was added twice as much as the solid content of tea, stirred and dissolved. The solution had a Brix of 14.1% and a weight of 123 kg. This solution was concentrated with a reverse osmosis membrane (Nitto Denko: NTR-759 HG, liquid temperature 35 ° C., pressure 2.0 MPa, circulation flow rate 10 L / hr) to obtain 55 kg of a Brix 29.1% concentrated solution.

Implemented item 1 <FC>
The same steps as in Example 1 were repeated four times to obtain 224 kg of a Brix 5.2% black tea extract. To this extract, maltodextrin of DE 17-21 (Sanei saccharification: NSD 700) was added twice as much as the solid content of tea, stirred and dissolved. The solution had a Brix of 13.7% and a weight of 256 kg. This solution was concentrated with a freeze concentrator (GEA Niro: NFC-W6). The operation of the freeze concentrator was carried out so that the ratio of in-apparatus ice crystals was 30 to 50% under the condition that the difference between the temperature of the extract solution in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. This concentration yielded 80 kg of a Brix 30.3% concentrate.

<Method of measuring aroma component>
The aroma components of the black tea extract obtained in the above example were measured.
10 g of a solution obtained by diluting a tea extract or concentrated tea extract with water to a solid content of 100 mg / 10 mL (adding cycloheptanol as an internal standard substance to a final concentration of 50 ppb), 3 g of sodium chloride in advance Into a 20 mL vial and subjected to GC / MS analysis using Solid Phase Micro Extraction (SPME).
(SPME-GC / MS conditions)
Device: TRACE GC ULTRA, TSQ QUANTUM XLS (Thermo) SPME fiber: 50/30 μm Divinylbenzene / Carboxen / Polydimethyl siloxane StableFlex
Extraction: 60 ° C., 30 minutes Column: SUPELCO WAX 10 (0.25 mm ID × 60 m × 0.25 μm, SUPELCO)
Oven program: 40 ° C. (hold for 2 minutes) to 3 ° C./min to 160 ° C. to 10 ° C./min to 280 ° C.
Carrier gas: Helium (100 kPa, constant pressure)
Injector: splitless, 240 ° C
Ionization: Electron Ionization Ionization voltage: 70 eV
The values are GC-MS peak area ratio (each aroma component / cycloheptanol 50 ppb)
The results of the measured aroma components of the tea extract are shown in Table 1.

In Table 1, n-hexanal, (E) -2-hexen-1-al, n-hexanol, (Z) -3-hexen-1-, based on the amount of aroma components of the black tea extract obtained in the examples. As for ol and (E) -2-hexen-1-ol, A: As a greenish aroma component, β-myrcene, D-limonene, cis-β-ocimene, trans-β-ocimene, 6-methyl-5-heptene -2-one, (E.Z) -3,5-octadien-2-one, (E, E) -3,5-octadien-2-one, .beta.-cyclocitral and methyl salicylate B: fruity aroma As components, linalool oxide (trans-franoid), linalool oxide (ci s-franoid), linalool, α-terpineol, linalool oxide (cis-pyranoid), linalool oxide (trans-pyranoid), β-damascenone, geraniol and β-ionone show their respective total values as C: floral aroma components The
In addition, Table 1 shows the total value of all the aroma components measured and the retention (%) of the aroma components after the concentration step relative to the amount of aroma components of the tea extract before concentration.

<Sensory evaluation>
The sensory evaluation of the tea extract and concentrated tea extract obtained in Examples 1 to 3 was performed.
Each tea extract and concentrated tea extract were diluted to 0.5% Brix with distilled water, and subjected to sensory evaluation at a drinking concentration. At that time, with respect to the concentrated tea extract solution to which dextrin was added, Brix of the dextrin added portion was subtracted to prepare so that Brix by the tea-derived component was equivalent to 0.5%. The beverage was prepared by diluting the extract prior to concentration as the control 5 points, and a panel of 5 people performed a 5-step evaluation (5 points in the best case, 1 point in the worst case) on the flavor and represented by the average value. The results are shown in Table 1.

From the results in Table 1,
In the concentrated black tea extract obtained from TFE concentration, the retention rate of the aroma component was remarkably decreased by 3.7% with the comparative product 1 without dextrin addition and 25.7% with the comparative product 6 with dextrin added . The evaluation points in the sensory evaluation were 2.0 and 2.8, respectively, and it was confirmed that the flavor was significantly lost.
With regard to RO membrane concentration, the retention rate of the aroma component is 64.7% for the comparative product 2 with no added dextrin, 58.2% for the comparative product 7 with added dextrin, which is a higher result than TFE concentration However, the sensory evaluation was 2.6 and 3.6, and the flavor was clearly lost as compared with the control tea extract and the product 1. Moreover, the retention rate of the aroma component was higher in Comparative Product 2 in which no dextrin was added than in Comparative Product 7 in which dextrin was added. From this, it became clear that, in RO membrane concentration, dextrin is not directly involved in retention of the aroma component in the concentration step.
After TFE concentration or RO membrane concentration to enhance the Brix of the extract, the freeze-concentrated Comparative Products 4 and 5 both had lost aroma components in the pre-concentration step. The retention rate of the aroma component of Comparative product 5 was 79.6%, which is the second highest result of the practical product 1. However, from the score of sensory evaluation of 3.6, the fact that the flavor is lost by the pre-concentration step is It was clear, and the flavor was clearly inferior to that of Example 1.
Comparative product 3 in which the freeze-concentration of the tea extract was attempted without adjusting Brix with dextrin did not cause separation of the ice crystals and the concentrate in the recrystallization apparatus, and the concentration could not be performed normally.
The product 1 in which dextrin was added and freeze-concentrated to these comparative products retained 98.3% of the aroma components as compared to the extract before concentration, and it was also evaluated in sensory evaluation 4. Almost no loss of flavor was felt compared to 8 and the control. In addition, in the product 1, the floral aroma component was increased compared to the extract before concentration, and a colorful smell was felt prominent in the sensory evaluation. From this, it was shown that the step of adding dextrin and performing freeze concentration was the most excellent means for concentrating tea extract.

<Preparation of Brix of tea extract>
The Brix 5.3% black tea extract obtained by the same process as Example 1 was made into Brix 6.3, 7.3, 9.0, 15.0, 20.0 and 25.0% by adding dextrin, respectively. The concentrated tea extract was prepared by the same freeze-concentrating step as in the practical product 1 except that it was adjusted (comparative product 8, practical products 2 to 6). The addition amount (parts by weight) of dextrin per part by weight of tea solid content and the results of sensory evaluation are shown in Table 2.

It was shown from Table 2 that concentrated tea extract having excellent flavor can be produced by performing freeze concentration after adjusting the tea extract to 7.3% Brix or more with dextrin. Comparative product 8 in which the Brix of the extract was 6.3% was low in Brix of the extract as in Comparative product 3, so that separation of the ice crystals and the concentrate did not occur, and concentration was not possible.
Also, it was shown that the amount of dextrin added to the extract liquid was excellent when it was 0.4 to 3.5 parts by weight per 1 part by weight of tea solids. On the other hand, in the product 6 in which 4.3 parts by weight of dextrin was added per 1 part by weight of tea solids, the sensory evaluation was slightly inferior to that of the other products in sensory evaluation 4.2 because the flavor of dextrin was felt.

<Production of tea extract by freeze-drying>
The same steps as in Example 1 were repeated four times to obtain 218 kg of Brix 5.3% black tea extract. To this extract, maltodextrin of DE 16-19 (Matsutani Chemical Industry: TK16) was added twice as much as the solid content of tea, and dissolved with stirring. The solution had a Brix of 14.3% and a weight of 241 kg. This solution was concentrated with a freeze concentrator (GEA Niro: NFC-W6). The operation was performed so that the ratio of ice crystals in the apparatus: 30 to 50%, under the condition that the difference between the temperature of the extract liquid and the temperature of the cooling solvent in the apparatus is 5 to 7 ° C. This concentration yielded 80 kg of a Brix 31.0 concentrate.
A portion of the concentrated tea extract was dried by a lyophilizer (EYELA: FDU-2100) to obtain a tea extract.
The tea extract was dissolved in water and subjected to sensory evaluation in the same manner as in the black tea extract. As a result, the flavor was excellent in the same manner as Example 1.

<Production of Concentrated Green Tea Extract>
The process of extracting 5 kg of green tea leaves with 50 liters of ion-exchanged water at 60 ° C. for 30 minutes, repeating 50 mesh filtration and centrifugation was repeated four times to obtain 160 kg of a Brix 2.9% green tea extract. To this extract, maltodextrin of DE 17-21 (San Saccharification: NSD 700) was added so as to have a Brix of 10.2%, and dissolved by stirring. The solution weight was 172 kg.
This solution was used as an initial input solution and concentration was started with a freeze concentrator (GEA Niro: NFC-W6). The operation was performed so that the ratio of ice crystals in the apparatus: 30 to 50%, under the condition that the difference between the temperature of the extract liquid and the temperature of the cooling solvent in the apparatus is 5 to 7 ° C. The additional solution after the preparation of ice crystals was prepared by adding maltodextrin to have a Brix of 7.5% added to 203 kg of Brix 2.9% green tea extract obtained by repeating the same steps as above five times. . This concentration yielded 80 kg of a Brix 26.0% concentrate.
When the sensory evaluation was performed by the method similar to the said concentrated black tea extract, it was excellent in the flavor similarly to the implementation goods 1.

<Production of Concentrated Jasmine Tea Extract>
8 kg of jasmine tea leaves were extracted with 70 liters of ion-exchanged water at 85 ° C. for 40 minutes, and 50 mesh filtration and centrifugation were repeated six times to obtain 273 kg of a 3.7% Brix jasmine tea extract. To this extract, maltodextrin of DE 17-21 (Sanei saccharification: NSD 700) was added twice as much as the solid content of tea, stirred and dissolved. The solution had a Brix of 10.3% and a weight of 294 kg. This solution was concentrated with a freeze concentrator (GEA Niro: NFC-W6). The operation of the freeze concentrator was carried out so that the ratio of in-apparatus ice crystals was 30 to 50% under the condition that the difference between the temperature of the extract solution in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. This concentration yielded 90 kg of a Brix 25.1% concentrate.
When the sensory evaluation was performed by the method similar to the said concentrated black tea extract, it was excellent in the flavor similarly to the implementation goods 1.

By adjusting the extract of teas to 7.3% or more of Brix by addition of dextrin, freeze concentration which does not require a preconcentration step such as TFE concentration or RO membrane concentration with loss of flavor can be performed.

Claims (6)

A method for producing a concentrated tea extract liquid, which comprises adjusting a tea extract to 13.7% to 20.0% by addition of dextrin and then freeze-concentrating, wherein the amount of the dextrin added is 1 part by weight of tea solids. The manufacturing method of the concentrated tea extract which is 2.0-3.5 weight part with respect to. The method according to claim 1, wherein the dextrin is maltodextrin of DE 16-21. The method according to any one of claims 1 to 2, wherein the tea is black tea. The manufacturing method of the tea extract which dries the concentrated tea extract obtained by the manufacturing method as described in any one of Claims 1-3. The method according to claim 4, wherein the drying process is lyophilization. Concentrated red tea extract or red tea extract obtained by the production method according to any one of according claims 1-5.