JP2015119657A - Concentrated tea extract by freeze concentration method and manufacturing method of extract - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freeze concentration method for efficiently manufacturing a concentrated tea extract excellent in flavor with overcoming a problem of concentration of tea extract by a freeze concentration method which can manufacture an extract maintaining excellent flavor where pure ice crystal and the extract cannot be separated because formation of ice containing a tea solid content occurs with rapid.SOLUTION: By adjusting an extract of teas to Brix 7.3% or more with adding dextrin, a high quality concentrated teas extract excellent in flavor can be efficiently provided.

Description

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

Methods for concentrating tea extract include concentrating with a rotary vacuum evaporator (flash evaporator concentration) using evaporation by heating or reduced pressure, concentrating with a plate type concentrating device (PHE concentration), and concentrating with 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 conventional techniques.
Concentration by evaporation is unavoidable that the flavor component is easily denatured, decomposed, oxidized, etc. by heating, so that the flavor is deteriorated, the composition of the flavor component is changed, and the aromatic component is significantly reduced due to evaporation. In the concentration method using a membrane, the fragrance component is adsorbed on the membrane and the composition of the fragrance component is changed, or it is discharged together with the permeate to impair the flavor.

In contrast to these concentration methods, freeze concentration cools the charged solution, turns the water in the solution into pure ice crystals, and separates the ice crystals from the solution. Is not given to the concentrated solution, so that a concentrated solution that retains the flavor balance before concentration and the amount of aroma components can be obtained.
However, normally, when a tea extract is concentrated by a freeze concentration method, there is a problem that ice containing tea solids is rapidly formed and cannot be separated into pure ice crystals and concentrate.

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

According to Patent Document 2, ice crystals are quickly produced by freezing tea extracts that have been considered unsuitable for freeze-concentration methods by tannase treatment in advance. A possible method is disclosed.

Patent Document 3 discloses that the concentration efficiency of freeze-concentration is reduced to a practical level by removing tannin, which is a bitter component, in advance in the freeze-concentration method, which is considered to be impractical for green tea. Is disclosed.

However, all of the techniques described in the above documents require that the components of the tea extract be removed or decomposed, and the adverse effects on the flavor of the concentrated tea extract after freeze concentration could not be avoided.

Therefore, provision of a method for efficiently producing a concentrated tea extract having the same flavor as the tea extract before concentration has been demanded.

JP 56-089802 JP 05-328901 JP2002-238458

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

Accordingly, an object of the present invention is to provide a freeze concentration method for efficiently producing a concentrated tea extract having an excellent flavor.

The present inventor examined the reason why the tea extract cannot be normally concentrated in the freeze concentration method. As a result, the concentration of the tea extract obtained by a general industrial method such as dough pickling, countercurrent extraction, shower type extraction, etc. is Brix6. It became clear that the cause was as low as 0.0% or less (about 1.0 to 6.0%).
In order to increase the Brix of the tea extract prior to freeze concentration, TFE concentration or RO membrane concentration was attempted as a preconcentration step for the tea extract, and freeze concentration was successful, but in this case, in the preconcentration step, Loss of flavor, change in composition of fragrance components and decrease in fragrance amount, inevitable provision of a pre-concentration device, time loss required for the pre-concentration step, and other problems.
Therefore, as a result of repeated ingenuity, the tea extract was adjusted to Brix 7.3% or more by addition of dextrin, and it was possible to freeze and concentrate the tea extract that did not require a preconcentration step. . Therefore, according to this production method, the inventors have reached the knowledge that a high-quality concentrated tea extract excellent in flavor can be efficiently obtained, and the present invention has been completed.

That is, the invention according to the claims of the present application relates to a method for producing a concentrated tea extract in which the tea extract is adjusted to Brix 7.3% or more by addition of dextrin and then freeze-concentrated.

  According to the present invention, an efficient freeze-concentration method with reduced flavor loss and a concentrated tea extract with reduced flavor loss are obtained.

  In the present invention, a tea extract whose Brix is adjusted to 7.3% or more by addition of dextrin is concentrated by freeze concentration.

The tea extract means fresh leaves and fresh stems of tea trees (Camelia sinensis var. Sinensis and Camellia sinensis var. Assamica, or hybrids thereof), or tea leaves (for example, sencha, gyokuro, kabusecha) produced using these as primary materials. Non-fermented tea such as bancha, roasted green tea, flower tea such as jasmine tea that has been moved to non-fermented tea, weakly fermented tea such as white tea, semi-fermented tea such as oolong tea, fermented tea such as black tea, puer tea It means a liquid obtained by extracting post-fermented tea etc.) as a raw material or a part thereof. Besides tea leaves, brown rice, barley, wheat, pigeons, corn, amaranth, quinoa, scallop, mozuku, licorice, lotus, perilla, pine, psyllium, rosemary, mulberry, ketsumeishi, soy, kelp, ganoderma, urchin, It is obtained by using leaves, stems, roots, fruits, seeds, etc. of various plants such as persimmon, sesame, safflower, ashitaba, cheng, guava, aloe, gymnema, tochu, dokudami, chicory, evening primrose, loquat, etc. Also good.

Examples of the tea extraction method include known methods such as a batch extraction method using a kneader or an extraction tank, a column extraction method using an extraction tower, and a shower extraction method. The extraction conditions are appropriately selected depending on the type of raw tea leaves, the type of extractor, the flavor, etc. For example, 3 to 50 parts by weight of extraction solvent may be used for 1 part by weight of raw tea leaves. 30 parts by weight is preferable in terms of extraction efficiency, manufacturing cost, quality, and the like. It is preferable to use water, warm water, or hot water as the extraction solvent because there is no problem in safety. The extraction temperature is not particularly limited, but is preferably 50 to 90 ° C and more preferably 60 to 80 ° C for non-fermented 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. Although the extraction time depends on the amount of extraction solvent and the extraction temperature, it is 30 seconds to 6 hours, preferably 3 minutes to 3 hours, and more preferably 4 minutes to 1 hour. During extraction, stirring is performed as necessary under normal pressure, increased pressure, or reduced pressure. After the above extraction process, filtration or centrifugation using a filter press or the like combined with a cartridge filter, flannel filter cloth, filter plate, filter paper, and filter aid is used. The tea extract may be obtained by solid-liquid separation by separation or the like. In the extraction step, an antioxidant may be added in order to suppress oxidation of the tea extract. Examples of the antioxidant include ascorbic acid, erythorbic acid or their metal salts that are recognized as food additives.

The concentrated tea extract is one obtained by removing a part of the water from the tea extract and means a tea extract in a state of being concentrated by a concentration process.
The degree of concentration is not particularly limited, but the Brix of the concentrated tea extract is preferably 20.0% or more. More preferably, Brix is 25.0% or more, and most preferably 30.0% or more.
In addition, Brix in this invention represents the numerical value obtained by the measurement by a vibration type density specific gravity meter (Kyoto Electronics Industry: DA-300).

Freeze concentration is a concentration method characterized by low temperature (below freezing point) and a closed system, with the principle that water is extracted from the mother liquor in the form of ice. It is. Therefore, it is possible to produce a high-quality concentrate having the same quality as the raw material with a very low residual ratio of low boiling point and low molecular components. The freeze concentration of the present invention is not particularly limited in conditions, and a commercially available general freeze concentration device can be used as it is. For example, in the case of a product manufactured by Glenco, it can be roughly divided into the following three devices. It is configured.
1) Surface scraped heat exchanger (Scraped Surface Heat Exchanger)
2) Recrystallizer
3) Washing column (wash Column)
Then, the surface scraping type heat exchanger is used to make the ice core, the ice is grown by the recrystallization apparatus, and the ice and the concentrated liquid are separated by the washing type separation cylinder.

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

The dextrin refers to a starch that has been gelatinized or decomposed with an acid such as α-amylase or hydrochloric acid or oxalic acid while gelatinizing, and examples thereof include maltodextrin, cyclodextrin, and branched dextrin.
Usually, a starch hydrolyzate expresses the degree of degradation in dextrose equivalent (DE), and a product in which DE is degraded to about 5 to 21 is called maltodextrin. In the present invention, it is preferable to use maltodextrins having DE5 to 21 in terms of no adverse effects on price and flavor, and those having DE16 to 21 are more preferable from the viewpoint of storage stability.

Dextrin may be added to the tea extract at any stage of the manufacturing process as long as it is before the freeze-concentration process. It is preferable because flavor loss due to modification or loss can be suppressed.

Dextrin may be added in combination with other carbohydrates. For example, those containing 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 liquid sugar, glucose fructose liquid sugar, agape extract, and honey can also be used. In addition, polyhydric alcohols such as glycerol can be used in the present invention.

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

The amount of dextrin added is not particularly limited as long as it is an amount that adjusts 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. 0.6-3.0 weight part is more preferable, and 0.8-2.0 weight part is further more preferable. Although the amount of dextrin added is less than 0.4 parts by weight, depending on the tea type and extraction conditions, Brix cannot be sufficiently increased, and if it exceeds 4.0 parts by weight, the effect of the unique flavor of dextrin itself In some cases, the flavor of the tea extract is inferior to starch.
In addition, the tea solid content in the present invention is a value derived from the Brix of a tea extract to which an additive such as dextrin is not added by the formula (Brix × liquid amount / 100).

Prior to the concentration step, the tea extract may be treated with tannase. By treating the tea extract with tannase, it is possible to prevent the occurrence of cream-down in the freeze concentrator, and prevent mechanical problems such as clogging of piping, valves, liquid pumps, malfunctions, filter clogging, etc. By making it easy to separate the ice crystals from the concentrated liquid, it contributes to the concentration of tea extract components before and after concentration, enabling high concentration, and increasing the efficiency of washing ice crystals. This can improve efficiency and prevent a decrease in yield.

  In the freeze concentration step, the concentrated tea extract can be continuously produced by continuously or intermittently charging the tea extract into the freeze concentration apparatus. By adding a tea extract adjusted to Brix 7.3% or more with dextrin, a concentrated tea extract excellent in flavor can be continuously produced. Further, by continuously using the tea extract to which dextrin is added, the occurrence of cream down in the freeze concentration apparatus can be prevented, and problems such as clogging of the 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, an appropriate drying treatment is adopted to form a powder or block tea extract. You can also. Examples of the drying process include spray drying, vacuum drying, freeze drying, and the like. In terms of cost, spray drying is preferable. From the viewpoint of maintaining aroma components, the tea extract is frozen and the water is sublimated by sublimating the ice to reduce moisture. Freeze drying is preferred.

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

According to the embodiment of the present invention, since no other concentration step is required as a pretreatment for freeze concentration, it is possible to provide a tea extract in which a decrease in aroma components is suppressed. Therefore, the food / beverage products excellent in flavor can be provided using the concentrated tea extract or tea extract which performed the freeze concentration process of this invention. Examples of food and beverage include beverages such as tea beverages, sports beverages, carbonated beverages, fruit juice beverages, milk beverages, alcoholic beverages, powdered beverages; frozen confectioneries such as ice creams, sherbets and ice candy; Japanese and Western confectionery It is possible to provide foods and drinks to which various functionalities such as chewing gums, chocolates, breads and the like; various snacks and the like are provided.

The following examples further illustrate the present invention. However, the present invention is not limited to this.

<Manufacture of tea extract>
10 kg of black tea leaves (Mitsui Norin: 90% Dimbra + 10% blend) were extracted with 90 L of ion-exchanged water at 85 ° C. for 40 minutes, filtered by 50 mesh and centrifuged to obtain 55 kg of Brix 5.3% black tea extract. .

<Concentration of black tea extract>
Comparative product 1 <TFE concentration>
The same process as in Example 1 was repeated three times to obtain 163 kg of Brix 5.3% black tea extract.
This extract was concentrated with a centrifugal thin film concentrator (Okawara Seisakusho: CEP-5S) under the conditions of 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 of 4 to 5 kPa. 20 kg of% concentrated solution was obtained.

Comparative product 2 <RO membrane concentration>
The same process as Example 1 was repeated twice to obtain 110 kg of Brix 5.4% black tea extract.
This extract was concentrated with a reverse osmosis membrane (Nitto Denko: NTR-759HG) under conditions of 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 process as in Example 1 was repeated four times to obtain 220 kg of Brix 5.2% black tea extract.
The extract is subjected to a freeze concentrator (GEA Niro: NFC-W6) under conditions where the difference between the extract temperature in the apparatus and the cooling solvent temperature is 5 to 7 ° C. (extract solution temperature −1.1 ° C., cooling solvent temperature At about −7.1 ° C., concentration was attempted. However, since the Brix of the extract was low, ice crystals were not generated and concentration was not possible.

Comparison product 4 <TFE preconcentration ⇒FC>
The same steps as in Example 1 were repeated 6 times to obtain 338 kg of Brix 5.2% black tea extract.
This extract was concentrated with a centrifugal thin film concentrator (Okawara Seisakusho: CEP-5S) under the conditions of 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 of 4 to 5 kPa. 158 kg of concentrated liquid increased to 6%.
Subsequently, concentration was started with a freeze concentrator (GEA Niro: NFC-W6) using the concentrated solution as an initial charging solution. As the additional input liquid after forming the ice crystals, 325 kg of Brix 5.2% extract obtained by repeating the same process as Example 1 6 times was used. The operation was performed such that the ice crystal ratio in the apparatus was 30 to 50% under the condition that the difference between the temperature of the extract in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. By this concentration, 70 kg of Brix 29.6% concentrate was obtained.

Comparative product 5 <RO membrane preconcentration ⇒FC>
The same process as Example 1 was repeated 6 times to obtain 331 kg of Brix 5.2% black tea extract.
This extract was concentrated with a reverse osmosis membrane (manufactured by Nitto Denko Corporation: NTR-759HG, liquid temperature 35 ° C., pressure 2.0 MPa, circulation flow rate 10 L / hr) to obtain 150 kg of Brix 10.9% concentrate.
Subsequently, concentration was started with a freeze concentrator (GEA Niro: NFC-W6) using the concentrated solution as an initial charging solution. As the additional input liquid after forming the ice crystals, 340 kg of Brix 5.3% extract obtained by repeating the same process as in Example 1 6 times was used. The freeze concentrator was operated under the condition that the difference between the temperature of the extract in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. so that the ice crystal ratio in the apparatus was 30 to 50%. By this concentration, 80 kg of Brix 30.3% concentrate was obtained.

<Concentration of black tea extract added with dextrin>
Comparative product 6 <TFE concentration>
The same process as in Example 1 was repeated twice to obtain 111 kg of Brix 5.3% black tea extract. To this extract, maltodextrin of DE 17-21 (San-ei saccharification: NSD700) was added in twice the amount of tea solids and dissolved by stirring. The solution had a Brix of 14.0% and a weight of 123 kg. This solution was concentrated with a centrifugal thin film concentrator (Okawara Seisakusho: CEP-5S) under the conditions of a liquid temperature of 30 to 32 ° C., a heating temperature of 76 to 80 ° C., a rotation speed of 803 rpm, and a vacuum of 4 to 5 kPa, and Brix 31.7% 40 kg of a concentrated solution was obtained.

Comparative product 7 <RO membrane concentration>
The same steps as in Example 1 were repeated twice to obtain 116 kg of Brix 5.2% black tea extract. To this extract, maltodextrin of DE 17-21 (San-ei saccharification: NSD700) was added in twice the amount of tea solids and dissolved by stirring. 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-759HG, liquid temperature 35 ° C., pressure 2.0 MPa, circulation flow rate 10 L / hr) to obtain 55 kg of Brix 29.1% concentrate.

Implemented product 1 <FC>
The same steps as in Example 1 were repeated 4 times to obtain 224 kg of Brix 5.2% black tea extract. To this extract, maltodextrin of DE 17-21 (San-ei saccharification: NSD700) was added in twice the amount of tea solids and dissolved by stirring. The Brix of the solution was 13.7% and the weight was 256 kg. This solution was concentrated with a freeze concentrator (GEA Niro: NFC-W6). The freeze concentrator was operated under the condition that the difference between the temperature of the extract in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. so that the ice crystal ratio in the apparatus was 30 to 50%. By this concentration, 80 kg of Brix 30.3% concentrate was obtained.

<Measurement method of aroma components>
The aroma component of the black tea extract obtained in the above example was measured.
10 g of a solution obtained by diluting a tea extract or concentrated tea extract with water to 100 mg / 10 mL of tea solids (adding cycloheptanol as an internal standard substance so that the final concentration is 50 ppb) was added in advance to 3 g of sodium chloride. The sample was placed in a 20 mL vial containing, and subjected to GC / MS analysis using a solid phase micro extraction (SPME).
(SPME-GC / MS conditions)
Equipment: TRACE GC ULTRA, TSQ QUANTUM XLS (Thermo)
SPME fiber: 50/30 μm Divinylbenzene / Carboxen / Polydimethylsiloxane StableFlex
Extraction: 60 ° C., 30 minutes Column: SUPELCO WAX10 (0.25 mm ID × 60 m × 0.25 μm, SUPELCO)
Oven program: 40 ° C. (2 minutes hold) 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
Numerical values are GC-MS peak area ratios (each aroma component / cycloheptanol 50 ppb)
The results of the aroma components of the measured tea extract are shown in Table 1.

In Table 1, based on the amount of aroma components in the tea extract obtained in the examples, n-hexanal, (E) -2-hexen-1-al, n-hexanol, (Z) -3-hexen-1- ol and (E) -2-hexen-1-ol: A: β-myrcene, D-limonene, cis-β-ocinene, trans-β-ocinene, 6-methyl-5-hepten as a green fragrance component For 2-one, (E.Z) -3,5-octadien-2-one, (E, E) -3,5-octadien-2-one, β-cyclocyclic and methyl salicylate, B: fruity fragrance As components, linalool oxide (trans-franoid), linalool oxide (ci s-franoid), linalool, α-terpineol, linalool oxide (cis-pyranoid), linalool oxide (trans-pyranoid), β-damascenee, geraniol, and β-ionone are C It was.
In addition, Table 1 shows the total value of all the aroma components measured and the retention rate (%) of the aroma component after the concentration step with respect to the aroma component amount of the tea extract before concentration.

<Sensory evaluation>
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 was diluted to 0.5% Brix with distilled water and subjected to sensory evaluation at a drinking concentration. At that time, the concentrated tea extract to which dextrin was added was prepared so that Brix corresponding to the dextrin addition was subtracted and Brix based on the tea-derived component was equivalent to 0.5%. The beverage obtained by diluting the extract before concentration was set as 5 points of control, 5 panelists evaluated the flavor (5 points for the best case and 1 point for the worst case), and expressed as an average value. The results are shown in Table 1.

From the results in Table 1,
Concentrated black tea extract obtained by TFE concentration had a significant decrease in retention of aromatic components in Comparative Product 1 without addition of dextrin (3.7%) and Comparative Product 6 with dextrin (25.7%). . The evaluation scores in the sensory evaluation were 2.0 and 2.8, respectively, and it was confirmed that the flavor was significantly lost.
Regarding the RO membrane concentration, the retention rate of the aroma component was 64.7% for Comparative Product 2 without dextrin and 58.2% for Comparative Product 7 with dextrin, which was higher than TFE concentration. However, the sensory evaluation was 2.6 and 3.6, and the flavor was clearly lost as compared with the tea extract or the control product 1 as a control. In addition, the comparative product 2 without addition of dextrin had a higher retention of aroma components than the comparative product 7 with addition of dextrin. From this, in RO membrane concentration, it became clear that dextrin is not directly involved in retention of aroma components in the concentration step.
In Comparative Products 4 and 5, which were freeze-concentrated after TFE concentration or RO membrane concentration in order to increase the Brix of the extract, both aroma components were lost in the preliminary concentration step. Although the retention rate of the aromatic component of the comparative product 5 was 79.6%, which was the second highest result of the practical product 1, the flavor was lost by the preconcentration step from the sensory evaluation score of 3.6. It was clear and the flavor was clearly not excellent with respect to the product 1.
Comparative product 3, which attempted to freeze and concentrate the tea extract without adjusting Brix with dextrin, did not cause ice crystals and concentrate to separate in the recrystallization apparatus, and could not be normally concentrated.
In comparison with the comparative product, the product 1 in which dextrin was added and freeze-concentrated retained 98.3% of the fragrance component even in comparison with the extract before concentration, and in sensory evaluation, 4. No loss of flavor was felt compared to 8 and control. Further, in the product 1, the floral fragrance component was increased from the extract before concentration, and a gorgeous fragrance was noticeably felt during sensory evaluation. From this, it was shown that the process of adding freeze-dextrin and performing freeze concentration is the most excellent tea extract concentration means.

<Adjustment of Brix of tea extract>
By adding dextrin, the Brix 5.3% black tea extract obtained in the same process as Example 1 was added to Brix 6.3, 7.3, 9.0, 15.0, 20.0 and 25.0%, respectively. Except for adjustment, a concentrated tea extract was prepared by the same freeze-concentration step as that of Example Product 1 (Comparative Product 8, Example Products 2 to 6). Table 2 shows the amount of dextrin added per part by weight of tea solids (parts by weight) and the results of sensory evaluation.

Table 2 shows that a concentrated tea extract excellent in flavor can be produced by freeze concentration after adjusting the tea extract to Brix 7.3% or more with dextrin. Comparative product 8 with an extract Brix of 6.3%, like Comparative product 3, had a low Brix extract, so that the ice crystals and the concentrate did not separate and could not be concentrated.
Moreover, it was shown that the amount of dextrin added to the extract has an excellent flavor as long as it is 0.4 to 3.5 parts by weight per 1 part by weight of tea solids. On the other hand, the product 6 in which 4.3 parts by weight of dextrin was added per 1 part by weight of tea solids was slightly inferior to the other products with sensory evaluation 4.2 because the flavor of dextrin was felt.

<FC⇒Manufacture of tea extract by freeze drying>
The same steps as in Example 1 were repeated 4 times to obtain 218 kg of Brix 5.3% black tea extract. To this extract, maltodextrin of DE16-19 (Matsutani Chemical Industry: TK16) was added in twice the amount of tea solids and dissolved by 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 such that the ice crystal ratio in the apparatus was 30 to 50% under the condition that the difference between the temperature of the extract in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. By this concentration, 80 kg of Brix 31.0 concentrate was obtained.
A part of this concentrated tea extract was dried with a freeze dryer (EYELA: FDU-2100) to obtain a tea extract.
When this tea extract was dissolved in water and subjected to sensory evaluation in the same manner as the black tea extract, the flavor was excellent as in the case of Example Product 1.

<Manufacture of concentrated green tea extract>
Extracting 5 kg of green tea leaves with 50 L of ion-exchanged water at 60 ° C. for 30 minutes, repeating 50 mesh filtration and centrifuging 4 times, 160 kg of Brix 2.9% green tea extract was obtained. To this extract, DE 17-21 maltodextrin (Seiei saccharification: NSD700) was added and dissolved with stirring so that Brix would be 10.2%. The solution weight was 172 kg.
Using this solution as an initial charging solution, concentration was started with a freeze concentrator (GEA Niro: NFC-W6). The operation was performed such that the ice crystal ratio in the apparatus was 30 to 50% under the condition that the difference between the temperature of the extract in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. The additional charge after the ice crystals were prepared was obtained by adding maltodextrin so that Brix would be 7.5% to 203 kg of Brix 2.9% green tea extract obtained by repeating the same process five times. . By this concentration, 80 kg of Brix 26.0% concentrate was obtained.
When sensory evaluation was performed in the same manner as the concentrated black tea extract, it was excellent in flavor as in the case of Example 1.

<Manufacture of concentrated jasmine tea extract>
The process of extracting 8 kg of jasmine tea leaves with 70 L of ion exchanged water at 85 ° C. for 40 minutes, 50 mesh filtration, and centrifugal separation was repeated 6 times to obtain 273 kg of Bris 3.7% jasmine tea extract. To this extract, maltodextrin of DE 17-21 (San-ei saccharification: NSD700) was added in twice the amount of tea solids and dissolved by stirring. 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 freeze concentrator was operated under the condition that the difference between the temperature of the extract in the apparatus and the temperature of the cooling solvent was 5 to 7 ° C. so that the ice crystal ratio in the apparatus was 30 to 50%. This concentration yielded 90 kg of Brix 25.1% concentrate.
When sensory evaluation was performed in the same manner as the concentrated black tea extract, it was excellent in flavor as in the case of Example 1.

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

Claims (11)

A method for producing a concentrated tea extract in which a tea extract is adjusted to Brix 7.3% or more by addition of dextrin and then freeze-concentrated. The production method according to claim 1, wherein the dextrin is maltodextrin. The process according to claim 1 or 2, wherein the maltodextrin has a DE of 16 to 21. The production method according to any one of claims 1 to 3, wherein the amount of dextrin added is 0.4 to 4.0 parts by weight with respect to 1 part by weight of tea solids. The production method according to any one of claims 1 to 4, 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 Claim 1 to 5. The production method according to claim 6, wherein the drying treatment is freeze-drying. The concentrated tea extract or tea extract obtained by the manufacturing method as described in any one of Claim 1 to 7. A method for suppressing flavor loss during concentration of a concentrated tea extract that is freeze-concentrated after adjusting the tea extract to Brix 7.3% or more by addition of dextrin. The method according to claim 9, wherein the dextrin is maltodextrin. The method according to claim 9 or 10, wherein maltodextrin has a DE of 16 to 21.