AU2011216786B2 - Manufacturing method for raw tea material used in beverages - Google Patents

Abstract

Provided is a manufacturing method for a raw tea material used in beverages whereby degradation odors resulting from long-term storage of the tea beverage can be suppressed. The manufacturing method for the raw tea material is characterized by the inclusion of a step for subjecting the cuticular layer of tea leaves to a reduction treatment. One example of the cuticular layer reduction treatment is to bring the front and/or back surface(s) of the tea leaves into contact with hot water, which flows in a substantially horizontal direction onto the surface of the tea leaves at a speed of 20-120 m/min at a temperature of 60-100°C, for a period of 10-120 seconds.

Description

1 DESCRIPTION METHOD OF PRODUCING A RAW TEA MATERIAL FOR A BEVERAGE TECHNICAL FIELD [0001] The present invention relates to a method of producing a raw tea material for a beverage that can be suitably used as a raw material of a tea beverage, particularly a tea beverage packed in a container that is filled into a can, a PET bottle, or the like. BACKGROUND ART [0002] Generally, a green tea has been usually drunk on the very day when it is made with a teapot. However, currently, with prevalence of a tea beverage packed in a container that is filled into a can, a PET bottle, or the like, the 2 tea beverage packed in a container may be stored sometimes for a long period. In such a case, problems such as generation of unusual odor have occurred. Therefore, there has been important a method of suppressing oxidation, deterioration, or the like of a tea beverage, and suppressing generation of unusual odor or the like at the time of production or storage of the tea beverage. [00033 Patent Document 1 described below discloses a method of producing a tea beverage, which has suppressed unpleasant heating odor (retort odor), by extracting teas with 20'C or less of cold water, and removing the obtained extraction liquid of cold water, and then extracting again the residual teas with 300C to 950C of warm water. [0004] 3 Patent Document 2 described below discloses a method of producing a green tea beverage, which has reduced generation of unusual odor at the time of heating sterilization, by extracting green tea leaves with -5 to 9'C of water (the first process), extracting the extraction residue of the first process with 50 to 100 0 C of warm water (the second process), and mixing the extraction liquid obtained in the first process and the extraction liquid obtained in the second process, and then subjecting the mixture to sterilization treatment. CITATION LIST PATENT DOCUMENT [0005] Patent Document 1: JP Hll-113491 A Patent Document 2: JP 3590027 B1 4 DISCLOSURE OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION [0006] A cuticle layer is present on the surface and the rear face of a tea leaf, and is said to play a role of preventing excessive moisture evaporation or bacterial infection. It is said that the cuticle layer contains a polymer of unsaturated fatty acid referred to as cutin as a major component, and other wax components. The present inventors earnestly studied, and as a result, found that by reducing the weight of the cuticle layer, it is possible to suppress deterioration of tea leaves, and it is possible to suppress generation of unusual odor or the like from a long period of storage of a tea beverage, and completed the invention.

5 [0007] Therefore, an object of the invention is to provide a method of producing a raw tea material for a beverage, which makes it possible to suppress deterioration odor of a tea beverage, particularly deterioration odor due to a long period of storage. MEANS FOR SOLVING PROBLEM [0008] The method of producing a raw tea material for a beverage of the invention comprises a process of conducting a treatment of reducing the cuticle layer of a tea leaf. [0009] The method of producing a raw tea material for a beverage of the invention reduces unsaturated fatty acid in the cuticle layer with a treatment of reducing the cuticle 6 layer of a tea leaf, and a tea beverage extracted from a raw tea material produced by such production method, is less likely to be deteriorated, and can suppress generation of unusual odor. [0009a] In an aspect of the invention there is provided a method of producing a raw tea material for use in making a beverage, the method comprising treating tea leaves to reduce the cuticle layer of the tea leaves, wherein the method includes the steps of contacting the tea leaves with flowing water at a temperature of between 60'C to 100'C and a flow rate of 20 m/minute to 120 m/minute, for between 10 seconds to 120 seconds, whereby the ratio of the weight of the cuticle layer relative to the weight of fiber of the tea leaves obtained by treating the raw tea material by the method is 0.45 to 3.00.

6a [0009b] A further aspect of the invention provides a method of reducing the cuticle layer of tea leaves, the method comprising contacting the tea leaves with flowing water at a temperature of between 60 0 C to 100 0 C and at a flow rate of between 20 m/minute to 120 m/minute, for a period of between 10 seconds to 120 seconds, whereby the resultant treated tea leaves have a ratio of the weight of the cuticle layer relative to the weight of fiber of the tea leaves of 0.45 to 3.00. [0009c] Comprises/comprising and grammatical variations thereof when used in this specification are to be taken to specify the presence of stated features, integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

6b MODE(S) FOR CARRYING OUT THE INVENTION [0010] Hereinafter, one embodiment of the method of producing a raw tea material for a beverage of the invention will be described. However, the invention is not limited to this embodiment. [0011] The method of producing a raw tea material for a beverage of one embodiment of the invention includes a process of conducting a treatment of reducing the cuticle layer of a tea leaf.

7 [0012] In production of the raw tea material for a beverage of the invention, the raw tea material (Aracha tea) may be produced, for example, by performing a treatment of reducing the cuticle layer for plucked live tea leaves, and using the treated tea leaves, performing steaming treatment, rolling treatment and drying treatment similarly to a conventional one. This raw tea material may be further subjected to a finishing process. [0013] In addition, it is said that the cuticle layer is present on the surface and the rear face of a tea leaf, and plays a role of preventing excessive moisture evaporation or bacterial infection, and contains a polymer of unsaturated fatty acid referred to as cutin as a major component, other wax components, or the like. It is 8 considered that the unsaturated fatty acid becomes a decomposed matter of fatty acid, which becomes a cause for deterioration odor occurring when a tea beverage is stored for a long period. With the invention, the deterioration odor can be suppressed by reducing the cuticle layer containing cutin as a major component. [0014] The tea leaves in the invention represent live tea leaves, steamed tea leaves, or boiled tea leaves, and are not particularly limited in the species, the cultivation region, the cultivation method, the plucking season, or the like as long as the tea leaves are plucked leaves or stems from a tea plant, Camellia sinensis. More specifically, examples of the breed include, for example, Yabukita, Yutakamidori, Sayamakaori, Kanayamidori, 9 Okumidori, Saemidori, Tsuyuhikari, Benifuuki, Fuushun, and the like. [0015] The raw tea material in the invention broadly encompasses teas classified as a unfermented tea such as, for example, a steaming tea, a decocted tea, a refined green tea, a powdered green tea, a Bancha tea, a Tamaryoku cha (curled leaf tea), an oven-roasted tea, a Chinese green tea, or the like, and also encompasses a blend of two more kinds thereof. [0016] The beverage in the invention is a liquid containing an extraction liquid or an extract that is obtained by extraction of the raw tea material described above as a major component. The liquid includes, for example, a liquid that comprises only an extraction liquid that is 10 obtained by extraction of tea leaves, or a liquid obtained by dilution of the extraction liquid, or a liquid obtained by mixing of the extraction liquids with each other, or a liquid obtained by addition of an additive to any of the above-mentioned liquids, or a liquid obtained by dispersion of those dried of any of the above-mentioned liquids, and the like. In addition, the beverage in the invention encompasses a tea beverage packed in a container obtained by filling the above-mentioned liquid into a container. A container to be filled with the present green tea beverage packed in a container is not particularly limited. For example, a plastic-made bottle (so-called PET bottle), a can of metal such as steel and aluminum, a bottle, a paper container, and the like may be used, and particularly, a transparent container such as a PET bottle may be preferably used as the container.

11 In addition, the "major component" encompasses a meaning that containing of other components is acceptable within a range of not interrupting the functions of the major component. At this time, the content ratio of the major component is not specified, but an extraction liquid or an extract that is obtained by extraction of a green tea, preferably takes up 50% or more by mass, particularly 70% or more by mass, and particularly 80% or more by mass (including 100%) in the solid content concentration in the beverage. [0017] The treatment of reducing the cuticle layer of a tea leaf may be performed by putting tea leaves into warm water flowing at 20 m/minute to 120 m/minute, preferably 30 m/minute to 120 m/minute, and particularly preferably 60 m/minute to 120 m/minute of the flow rate, and contacting 12 the tea leaves with the warm water for 10 seconds to 120 seconds, preferably 15 seconds to 90 seconds, and particularly preferably 30 seconds to 90 seconds. This contact is preferably performed on either one surface or both faces of the surface and the rear face of the tea leaves, and more preferably in approximately horizontal direction with respect to the face thereof although any direction may be good. By this, the reduction rate of the cuticle layer can be enhanced. In addition, the temperature of the warm water is preferably 60'C to 100 0 C, particularly preferably 70'C to 100'C, and further preferably 90'C to 100'C. [0018] As a more specific method, the weight of the cuticle layer can be reduced, for example, by retaining warm water in a cylindrical container such as a cylindrical pot having 13 20 to 40 cm of the diameter, and creating circulation to cause turbulence with a pump, a stirring body, or the like, and subjecting the tea leaves in the circulation, and after appropriate time, recovering the tea leaves. In addition, the flow rate when the warm water is circulated and brought into contact with the tea leaves as described above, represents a flow rate at a location of about 8 cm from the center of the container. In addition, the weight of the cuticle layer can be also reduced, for example, by connecting a pump with a pipe having 23.0 mm of the internal diameter, circulating warm water in this pipe, supplying tea leaves from a supply port of this pipe, and allowing the tea leaves to flow in the pipe, and discharging the tea leaves from a discharge port. At this time, adjustment of the contact time of the tea leaves with the warm water may be performed by adjustment 14 of the flow rate of the warm water, the length of the pipe, or the like. [0019] In a case where the treatment of reducing the cuticle layer is performed using a pipe, it is preferable that there is difference in the rate between the warm water and the tea leaves flowing in the pipe, and they flow in a state of irregular flow line (turbulence). For example, it is represented that Re = DV/V (D: pipe internal diameter, V: average flow rate, V: dynamic coefficient of viscosity), and Reynolds number, which represents flow properties, is preferably adjusted such that Re > 30,000, and particularly Re > 70,000. In addition, the flow in a state of irregular flow line by irregular movement of the turbulent tea leaves and the warm water, is referred to as the turbulence, and the 15 flow in a state where the tea leaves and the warm water maintain regular flow line is referred to as the layer flow. [0020] The reduction rate of the cuticle layer is preferably 8% to 40%. In addition, the reduction rate of the cuticle layer represents a reduction ratio of the weight of the cuticle layer of the tea leaf after the treatment of reducing the cuticle layer, relative to the weight of the cuticle layer of the tea leaf before the treatment of reducing the cuticle layer. When the reduction rate is 8% or more, it is possible to suppress generation of deterioration odor after a long period of storage. When the reduction rate is 40% or less, the raw tea material becomes a raw tea material that has excellent flavor.

16 From such viewpoint, the reduction rate of the cuticle layer is particularly preferably 10% to 40%, and further preferably 15% to 30%. In adjustment of the reduction rate of the cuticle layer, the temperature and the flow rate of the warm water, the contact time of the tea leaves with the warm water, or the like may be appropriately adjusted. More specifically, when the temperature of the warm water is high, the flow rate of the warm water is fast, or the contact time is long, the reduction rate of the cuticle layer increases, and thus the reduction rate of the cuticle layer may be appropriately adjusted in consideration of them. [00211 The tea leaves after being subjected to the treatment of reducing the cuticle layer preferably has 0.45 to 3.00 17 of the ratio of the weight of the cuticle layer relative to the weight of fiber of the tea leaves (cuticle layer/fiber). From this, the tea leaves become a raw tea material for a beverage that is suitable for a long period of storage, and has excellent flavor. From such viewpoint, the ratio of the weight of the cuticle layer of the tea leaves relative to the weight of fiber of the tea leaves (cuticle layer/fiber) is particularly preferably 0.50 to 2.80, and further preferably 0.80 to 2.00. In adjustment to this ratio, the temperature and the flow rate of the warm water, or the contact time with warm water in the treatment of reducing the cuticle layer may be appropriately adjusted. [0022] 18 In the raw tea material of the invention, the ratio of the weight of sucrose relative to the weight of bitter taste components, which are oxalic acid and caffeine (sucrose/bitter taste component), is preferably 0.45 to 2.15. Oxalic acid is a component that senses astringent taste, caffeine is a component that senses bitter taste, and sucrose is a component that senses sweet taste. The adjustment of the weights of these components allows a raw tea material that can sense moderate nutritious taste. From such viewpoint, the ratio of the weight of sucrose relative to the weight of the bitter taste component of the raw tea material is particularly preferably 0.60 to 2.00, and further preferably 0.80 to 1.80.

19 In adjustment of this ratio, the temperature of the warm water, the flow rate of the warm water, or the contact time of the tea leaves with the warm water in the treatment of reducing the cuticle layer may be appropriately adjusted. More specifically, when the flow rate of the warm water is fast, or the contact time is long, the ratio of the weight of sucrose relative to the weight of the bitter taste components increases, and thus the ratio may be appropriately adjusted in consideration of them. [0023) The weight of catechin in the raw tea material of the invention is preferably 5 to 20% by weight in the raw tea material. Catechin is a component that senses astringent and bitter taste, and adjustment of the percentage of this allows a raw tea material that can sense tea feeling.

20 From such viewpoint, the percentage of catechin in the raw tea material is particularly preferably 7 to 18% by weight, and further preferably 9 to 17% by weight. In addition, the catechin in the invention means total 8 kinds of catechin (C), gallocatechin (GC), catechin gallate (Cg), gallocatechin gallate (GCg), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECg), and epigallocatechin gallate (EGCg). In adjustment of the percentage of this, the percentage may be adjusted by, for example, adjusting the contact time of the tea leaves with the warm water, or selecting the tea season of the tea leaves to be used in the treatment of reducing the cuticle layer. [0024] The residual rate of catechin in the raw tea material of the invention is preferably 85% to 100%. In addition, 21 the residual rate of catechin represents a ratio of the weight of catechin in tea leaves that have been subjected to the treatment of reducing the cuticle layer, relative to the weight of catechin in tea leaves not subjected to the treatment of reducing the cuticle layer. This range of the ratio allows a raw tea material that can sense better tea feeling in comparison to an untreated product. From such viewpoint, the residual rate of catechin is particularly preferably 90% to 100%, and further preferably 93% to 100%. In adjustment of this residual rate, for example, the contact time of the tea leaves with the warm water, or the like in the treatment of reducing the cuticle layer may be appropriately adjusted. [0025] 22 Measurements of the weights of the cuticle layer, the fiber, the sucrose, the oxalic acid, the caffeine, and the catechin mentioned above, may be performed, for example, as listed in Examples described below. [0026] A tea beverage that is extracted from the raw tea material for a beverage produced using live tea leaves that has been subjected to the treatment of reducing the cuticle layer, has reduced unsaturated fatty acid, and has little generation of deterioration odor even after a long period of storage, and particularly can be suitably used as a tea beverage packed in a container. EXAMPLES [0027] 23 Hereinafter, Examples of the invention will be described. However, the invention is not limited to the Examples. [0028] Tests 1 to 6 listed below were performed. In addition, the weight of sucrose, the weight of catechin, the weight of caffeine, the weight of oxalic acid, the weight of the cuticle layer, and the weight of fiber listed below were measured as described below. [0029] <Weight of sucrose> (1) Method of Adjusting Sample 50 mg of pulverized raw tea material was taken, added with 50 mg of ultrapure water and extracted with ultrasonic wave for 15 minutes. 500 pL of the extracted sample was taken, added with 100 JL of 100 mM sodium hydroxide (NaOH), 24 100 pL of 50 ppm lactose, and 400 [L of ultrapure water, and well stirred, which was taken as a sample, and quantified by the calibration curve method under the conditions described below with high-performance liquid chromatography (HPLC), to measure the weight of sucrose. (2) Analysis Condition e Analysis column: HPLC sugar analysis device manufactured by Dionex Corporation - Column: Carbopack PA1 (4.6 mm x 250 mm) (P/N35391 manufactured by Dionex Corporation) - Column temperature: 30'C - Flow rate: 1.0 mL/min - Gradient condition: See Table 1 described below [0030] [Table 1] TIME Flow (ml) Phase A (%) Phase B (%) Phase C (%) (min) INITIAL 1 15 0 85 25 14 1 15 0 85 30 1 100 0 0 31 1 0 100 0 40 1 0 100 0 41 1 15 0 85 55 1 15 0 85 [0031] <Weight of Catechin and Weight of Caffeine> The fraction (mass %) of catechin or caffeine relative to the total mass of the dry tea leaves was measured by the method described below. (1) Method of preparing sample 200 mg of pulverized raw tea material was taken, and added with 100 mL of 20% acetonitrile, and extracted with ultrasonic wave for 60 minutes. This extraction liquid was filtered with a membrane filter (0.45 tm), which was taken as a sample, and quantified by the calibration curve method under the conditions described below, to measure the weight of catechin or the weight of caffeine.

26 (2) Analysis condition e Analysis device: Xbridge shield RP18 3.5 mm x 150 mm manufactured by Waters Corporation e Column temperature: 40 0 C e Flow rate: 0.5 mL/min * Mobile Phase: Phase A water, Phase B acetonitrile, Phase C 1% phosphoric acid . Injection amount: 5 pL - Detector: UV Detector UV230 nm manufactured by Waters Corporation o Gradient condition: See Table 2 described below [0032] [Table 2] TIME Flow (ml) Phase A (%) Phase B (%) Phase C (%) (min) INITIAL 0.5 83 7 10 5 0.5 83 7 10 7 0.5 80 10 10 12 0.5 72 18 10 27 23 0.5 65 25 10 30 0.5 30 60 10 40 0.5 83 7 10 [0033] <Weight of oxalic acid> 100 mg of pulverized raw tea material as a sample was measured and taken in 100 mL measuring flask, added with 10 mL of 1N hydrochloric acid solution, and mass-upped with distilled water. This was stood for 30 minutes or more, which was taken as the extraction solution. This extraction solution was filtered with a 0.45 pm filter, and this filtrate was taken as a sample, and the total weight of oxalic acid was measured using capillary electrophoresis. The electrophoresis fluid used was 20 mM quinolinic acid and 0.25 mM tetradecyltrimethylammonium hydroxide, which was adjusted to pH 8.0 with 2 M Tris(2-amino-2 hydroxymethyl-1,3-propanediiol).

28 [0034] <Weight of cuticle layer> 30 Pieces of tea leaves were punched to a disk shape with a cork borer having 20 mm of the diameter, and 30 pieces of disks were prepared (3.14 cm 2 per piece). These 30 pieces of the disks were soaked in a reaction fluid, and reacted at 40'C for 24 hours. The reaction fluid is a mixture of 20 mL phosphoric acid-citric acid buffer fluid (pH 3.0), 2 mL cellulase (1.5 L novozyme Celluclast), and 0.5 mL pectinase (novozyme Pectinex Ultra SP-L). After the reaction, the transparent membrane (cuticle layer) on the surface of the disk was recovered from the two sides of tea leaves, washed with an ultrasonic wave washer, and freeze dried. The weight of 30 pieces of the disks (94.2 cm 2 ) was measured, and then converted to a weight per 50 cm 2 , which was taken as the weight of the cuticle layer (mg).

29 [0035] <Weight of fiber> Tea leaves were dried with a microwave, and then pulverized with a cyclone mill manufactured by UDY CORPORATION, and filled into a dedicated cell. The amount of fiber was culculated with INSTALAB 600 near-infrared analyzer of tea component manufactured by Shizuoka-Seiki Corporation, and the content of fiber (mass %) relative to the total mass of the dry tea leaves were calculated, and the weight of fiber was measured. [00363 <Test 1> In Test 1, mainly with change of the temperature and the flow rate of the warm water, the change of the weight of the cuticle layer was investigated.

30 Yabukita species produced in Shizuoka Prefecture (second flush tea) was used as tea leaves, and Samples 1 to 5 described below were prepared. [0037] (Sample 1) The tea leaves were subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner to conventional one, to prepare the Aracha tea of Sample 1. [0038] (Sample 2) 10 L water of normal temperature (about 20 0 C) was retained in a cylindrical container having about 30 cm of the diameter, and this water was stirred by rotation so as to cause turbulence with a stirring machine, and circulated at about 60 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into the container, 31 and subjected for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner to conventional one, to prepare the Aracha tea of Sample 2. [0039] (Sample 3) 10 L warm water of 90'C was retained in a cylindrical container having about 30 cm of the diameter, and a metal mesh put in with 150 g of the tea leaves was put into this container. The tea leaves were soaked, and stood for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used 32 and subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner to conventional one, to prepare the Aracha tea of Sample 3. [0040] (Sample 4) 10 L warm water of 90'C was retained in a cylindrical container having about 30 cm of the diameter, and a metal mesh put in with 150 g of the tea leaves was put into this container. The tea leaves were soaked, and stood for 150 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and subjected to steaming treatment, rolling treatment and drying treatment in a similar manner to conventional one, to prepare the Aracha tea of Sample 4. [0041] 33 (Sample 5) 10 L warm water of 90 0 C was retained in a cylindrical container having about 30 cm of the diameter, this water was stirred by rotation so as to cause turbulence with a stirring machine, and circulated at about 60 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into the container, and subjected for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner to conventional one, to prepare the Aracha tea of Sample 5. [0042] (Analysis Test) 34 For Sample 1, the weight of the cuticle layer of the tea leaf after being plucked was measured, and for Samples 2 to 5, the weight of the cuticle layer of the tea leaf after being recovered from the container was measured. In addition, the weight of catechin was measured for the Aracha teas of Samples 1 to 5. These results are listed in Table 3 described below. [0043] (Beverage) 10 g of each Aracha tea of Samples 1 to 5 was taken, and extracted with 1000 mL distilled water of 70*C for 3.5 minutes. The residue was removed using a metal mesh of 150 mesh. This extraction liquid was rapidly cooled to room temperature in ice water, and subjected to centrifugal isolation (700 rpm, 10 minutes) treatment with use of SA1 continuous centrifugal isolator manufactured by Westphalia, 35 and the insoluble fraction was removed. Then, the extraction liquid was added with L-ascorbic acid to 300 ppm with respect to the blend mass-up amount (1000 mL), and adjusted to pH 6.0 with sodium bicarbonate. This blend fluid was UHT-sterilized for 30 seconds in a range of 133 0 C to 135'C for 30 seconds. This blend was filled into a PET bottle, and cooled to room temperature (about 25'C) in flowing water, whereby to prepare the tea beverage packed in a container. [0044] (Sensory Test) First, evaluations of the fresh aroma and the nutritious taste were performed by 7 specialist panelists with respect to the Aracha teas of Samples 1 to 5. Then, the above-mentioned beverages prepared from each of Samples 1 to 5 were drunk by the panelists, and evaluations of the 36 fresh aroma and the nutritious taste were performed. And, after 2 weeks, the above-mentioned beverages stored under the condition of 55*C (for evaluations of the temporal test) and the above-mentioned beverages stored under the condition of 4C (for comparison of the temporal test) were drunk by the same panelists, and evaluations for the fresh aroma, the nutritious taste, and the temporal stability were performed. In addition, the evaluation was conducted by giving any score of the 1 to 4 points described below, in which 3.5 or more of the average points of the 7 panelists was indicated as "©D (double circle)", 3 or more and less than 3.5 was indicated as "0 (circle)", and 2 or more and less than 3 was indicated as "A (triangle) ", and less than 2 was indicated as "x (cross)". In addition, as the total evaluation, the average points of the fresh aroma and the 37 nutritious taste for the Aracha teas were calculated, and the average points of the fresh aroma, the nutritious taste, and the temporal stability for the tea beverages packed in a container were calculated, and the evaluations were conducted as described above. These test results are listed in Table 3 described below. [0045] <Fresh aroma> 4 Points = Very strong 3 Points = Strong 2 Points = Somewhat weak 1 Point = Weak [0046] <Nutritious taste> 4 Points = Very good 3 Points = Good 38 2 Points = Somewhat poor 1 Point = Poor [0047] <Temporal stability> 4 Points = Very high 3 Points = high 2 Points = Somewhat low 1 Point = low [0048] [Table 3] Form Evaluation Item Sample Sample Sample Sample Sample 1 2 3 4 5 Live Weight of cuticle layer 45.1 41.9 42.0 33.0 33.4 leaves (mg) Aracha Weight of catechin (% by 15.2 15.1 14.4 12.9 14.5 tea weight) Aracha Fresh aroma 0 0 0 0 0 tea Nutritious taste 0 0 0 0 39 Total evaluation 0 0 0 0 Fresh o o 0 0 Right after aroma sterilization Nutritious 0 0 0 x 0 taste Fresh x 0 0 aroma After Beverage temporal test packed in a Nutritious o 0 x 0 container taste Temporal stability 0 0 @ @ Total evaluation o 0 0 @ [0049] (Results of Test 1) 40 From Samples 2 to 5, it was found out that the temporal stability improves by reduction of the cuticle layer. From the results of Samples 3 and 4, it was found out that immersion only in warm water is poor in efficiency for reduction of the cuticle, and long time immersion causes effusion of catechin, which leads to somewhat inferior evaluation of the nutritious taste. In addition, from the results of Sample 5, it was found out that flowing water of warm water effectively reduces the cuticle layer, which leads to a tea beverage that is suitable for a long period of storage while maintaining the original flavor of tea. [0050] <Test 2> 41 In Test 2, mainly with change of a method of hitting tea leaves with warm water, the change of the reduction rate of the cuticle layer was investigated. Yabukita species produced in Shizuoka Prefecture (first flush tea) was used as tea leaves, and Samples 6 to 9 described below were prepared. [0051] (Sample 6) The tea leaves were subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner Comment: ":-i-'4/A-6" to conventional one, to prepare the Aracha tea of Sample 5. [0052] (Sample 7) Warm water of 80'C was sprayed in the shower shape at about 30 m/minute of the flow rate for 30 seconds in approximately vertical direction with respect to the 42 surface of the tea leaves. The tea leaves were recovered, and lightly washed out with tap water. These tea leaves were used and subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner to Comment: "+-/A 7" conventional one, to prepare the Aracha tea of Sample 6. [0053] (Sample 8) 10 L warm water of 80'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was circulated so as to become the layer flow at about 1 m/minute of the flow rate using a stirring machine. A metal mesh put in with 150 g of the tea leaves was put into this container, and subjected for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and 43 subjected to steaming treatment, rolling treatment, and drying treatment in a similar manner to conventional one, to prepare the Aracha tea of Sample 8. [0054] (Sample 9) 10 L warm water of 80'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated at about 30 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into this container, and subjected for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and subjected to steaming treatment, rolling treatment, and drying treatment in a 44 similar manner to conventional one, to prepare the Aracha tea of Sample 9. [0055] (Analysis Test) For Sample 6, the weight of the cuticle layer of the tea leaf after being plucked was measured; for Sample 7, the weight of the cuticle layer of the tea leaf after being sprayed with warm water was measured; and for Samples 8 and 9, the weight of the cuticle layer of the tea leaf after being recovered from the container was measured. From these measurement results, the reduction rate of the cuticle layer of each sample relative to the weight of the cuticle layer of Sample 6 was calculated. In addition, the weight of catechin of each Aracha tea of Samples 6 to 9 was measured, and the residual rate of catechin of each sample relative to the weight of catechin of Sample 6 was 45 calculated. These results are listed in Table 4 described below. [0056] (Beverage) Each Aracha tea of Samples 6 to 9 was used, and a tea beverage packed in a container was prepared similarly to Test 1 described above. [0057] (Sensory Test) The sensory tests were performed similarly to Test 1 described above except that each Aracha tea of Samples 6 to 9 and the tea beverage prepared therefrom were used, and a beverage stored for 1 month for the temporal test was used. These test results are listed in Table 4 described below. [0058] [Table 4] Form Evaluation Item Sample 6 1Sample 7 1Sample 8 1Sample 9 46 0% 7% 6% 15% Live Reduction rate of leaves cuticle layer Reductio Reductio Reductio Reductio n n n n Aracha Residual rate of 100% 97% 97% 98% tea catechin Fresh aroma 0 0 0 0 Aracha Nutritious taste 0 0 0 0 tea Total evaluation 0 0 0 0 Fresh A Right after 0 0 0 aroma sterilizatio n Nutritiou 0 0 0 0 s taste Fresh A A A x aroma After Beverage temporal packed test in a Nutritiou containe 0 s taste r A A Temporal stability x 0 Total evaluation 0 47 [0059] (Results of Test 2) When Samples 7 to 9 were compared, it was found out that the reduction rate of the cuticle layer was greater in a case where warm water was brought into contact with tea leaves to cause turbulence. In addition, it was found out that the residual rate of catechin does not change greatly from any direction. [0060] <Test 3> In Test 3, mainly with change of the flow rate of warm water and the contact time of tea leaves with the warm water, the change of the reduction rate of the cuticle layer was investigated.

48 Yabukita species produced in Shizuoka Prefecture (first flush tea) was used as tea leaves, and Samples 10 to 14 described below were prepared. [0061] (Samples 10 to 14) 10 L warm water of 80'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated in the flow rate listed in Table 5 described below. A metal mesh put in with 150 g of the tea leaves was put into this container, and subjected for the time described below. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and subjected to steaming treatment, rolling treatment, and drying treatment 49 similarly to a conventional one, to prepare the Aracha teas of Samples 10 to 14. [0062] (Analysis Test) For Samples 10 to 14, the weight of the cuticle layer of the tea leaf after being recovered from the container was measured, and the reduction rate of the cuticle layer of each sample relative to the weight of the cuticle layer of Sample 6 in Test 2 described above was calculated. In addition, the weight of catechin of each Aracha tea of Samples 10 to 14 was measured, and the residual rate of catechin of each sample relative to the weight of catechin of Sample 6 in Test 2 described above was calculated. Furthermore, the weight of sucrose, the weight of caffeine, and the weight of oxalic acid of the Aracha teas of Samples 10 to 14 were measured, and the ratio of the weight of 50 sucrose relative to the weight of caffeine and the weight of oxalic acid (the weight of bitter taste components) (sucrose/bitter taste component) was calculated. These results are listed in Table 5 described below. [0063] (Beverage) A tea beverage packed in a container was prepared similarly to Test 1 described above using each Aracha tea of Samples 10 to 14. [0064] (Sensory Test) The sensory tests were performed similarly to Test 1 described above except that each Aracha tea of Samples 10 to 14 and the tea beverage prepared therefrom were used, and the beverage stored for 1 month for the temporal test 51 was used. These test results are listed in Table 5 described below. [0065] [Table 5] Form Evaluation Item Sample Sample Sample Sample Sample 10 11 12 13 14 Flow rate 0 30 80 120 120 - (m/minute) Time (second) 15 15 75 90 135 3% 13% 25% 31% 42% Live Reduction rate of Reductio Reductio Reductio Reductio Reduct leaves cuticle layer n n n n ion Residual rate of 100% 98% 96% 93% 84% Aracha catechin tea Sucrose/bitter 0.42 0.52 1.55 1.85 2.22 taste component Fresh aroma 0 0 0 0 Aracha Nutritious taste 0 0 0 0 tea Total evaluation 0 0 0 0 52 Fresh A 0 0 0 aroma Right after sterilize tion Nutriti ous 0 0 0 0 taste Fresh x 0 0 Bevera aroma ge After packed temporal in a test contai ner Nutriti ous 0 0 0 taste Temporal stability o @ @ Total evaluation 0 @ @ [0066] (Results of Test 3) 53 It was found out that if the flow rate of warm water is faster, and the immersion time in warm water is longer, the reduction rate of the cuticle layer increases, and the residual rate of catechin decreases, and the value of the sucrose/bitter taste component increases. From the sensory evaluations, it was found out that neither too much residual cuticle layer, nor too much reduction of catechin is desirable, and there are suitable ranges of the residual cuticle layer. [0067] <Test 4> In Test 4, Aracha teas were prepared mainly with change of the temperature of water with which the treatment of reducing the cuticle layer was performed, and the change of the sensory evaluations of them was investigated.

54 Yabukita species produced in Shizuoka Prefecture (third flush tea) was used as tea leaves, and Samples 15 to 18 described below were prepared. [0068] (Samples 15 to 18) 10 L warm water of the temperature listed in Table 6 described below was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated at 100 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into this container, and subjected for 90 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and 450 g in total of the tea leaves were used and subjected to steaming treatment, rolling treatment, and 55 drying treatment similarly to a conventional one, to prepare the Aracha teas of Samples 15 to 18. [0069] (Beverage) A tea beverage packed in a container was prepared similarly to Test 1 described above using each Aracha tea of Samples 15 to 18. [0070] (Sensory Test) The tea beverages prepared from each sample were drunk by 6 specialist panelists, and evaluations of the low-grade tea odor and the nutritious taste were performed. And, after 2 months, the above-mentioned beverages stored under the condition of 37'C (for evaluations of the temporal test) and the above-mentioned beverages stored under the condition of 4 0 C (for comparison of the temporal test) were 56 drunk by the same panelists, and evaluations of the low grade tea odor, the nutritious taste, and the temporal stability were performed. In addition, the evaluation was conducted by giving any score of the 1 to 4 points described below, wherein 3.5 or more of the average points of the 6 panelists was indicated as "@ (double circle)", 3 or more and less than 3.5 was indicated as "0 (circle)", 2 or more and less than 3 was indicated as "A (triangle)", and less than 2 was indicated as "x (cross)". In addition, as the total evaluation, the average points of the low-grade tea odor, the nutritious taste, and the temporal stability were calculated, and evaluations were conducted similarly to those described above. These test results are listed in Table 6 described below. [0071] 57 <Low-grade tea odor> 4 Points = Very weak 3 Points = Weak 2 Points = Somewhat strong 1 Point = Strong [0072] <Nutritious taste> 4 Points = Very good 3 Points = Good 3 Points = Somewhat poor 1 Point = Poor [0073] <Temporal stability> 4 Points = Very high 3 Points = high 2 Points = Somewhat low 58 1 Point = low [0074] [Table 6] Sample Sample Sample Sample Form Evaluation Item 15 16 17 18 Temperature of water 40 60 90 100 (*C) Low-grade o o © © tea odor Right after sterilization Nutritious o o 0 taste Low-grade A Beverage tea odor packed in After a temporal test container Nutritious 0 0 0 taste Temporal stability o @ @ @ Total evaluation @@ 0 [0075] 59 (Results of Test 4) As listed in Samples 16 to 18, it was found out that sensory evaluations become good for a tea beverage prepared from tea leaves for which the treatment of reducing the cuticle layer is performed at 60 0 C to 100'C of the water temperature. [0076] <Test 5> With respect to the tea leaves after being subjected to the treatments A to C described below, rolling treatment and drying treatment were performed in a similar manner to conventional one, and an Aracha tea was prepared for every treatment and every tea season, respectively. Then, Aracha teas 1 to 7 were prepared according to Table 7, and extracted, whereby to prepare Tea beverages 1 to 7, and the sensory evaluations were performed.

60 [0077] (Treatment A) Steaming treatment was performed with respect to live tea leaves in a similar manner to conventional one. [0078] (Treatment B) 10 L warm water of 100'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated at about 120 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into the container, and subjected for 90 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and the obtained 450 g in total of 61 the tea leaves was subjected to steaming treatment in a similar manner to conventional one. [0079] (Treatment C) 10 L warm water of 90'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated at about 120 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into the container, and subjected for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and the obtained 450 g in total of the tea leaves was subjected to steaming treatment in a similar manner to conventional one. [0080] 62 (Blend) An Aracha tea obtained by performing the treatments A to C, followed by rolling treatment and drying treatment was blended in the ratio listed in Table 7 described below, whereby to prepare Aracha teas 1 to 7. [0081] [Table 7] Aracha Aracha Aracha Aracha Aracha Aracha Aracha tea 1 tea 2 tea 3 tea 4 tea 5 tea 6 tea 7 Autumn/w Autumn/w Autumn/w Second Second Second First Tea inter inter inter flush flush flush flush season flush flush flush tea tea tea tea IItea tea tea Treatment 90 80 70 50 40 20 0 A (%) Treatment 10 20 30 50 60 80 0 B(% Treatment 0 0 0 0 0 0 100 C (%) [0082] (Analysis Test) The weight of sucrose, the weight of caffeine and the weight of oxalic acid of the Aracha teas 1 to 7 were measured, and the ratio of the weight of sucrose relative 63 to the weight of caffeine and the weight of oxalic acid (the weight of bitter taste components) (sucrose/bitter taste component) was calculated. In addition, the weight of catechin of the Aracha teas 1 to 7 was measured. These results are listed in Table 8 described below. [0083] (Sensory evaluation) 10 g of the Aracha teas 1 to 7 was taken, and extracted with 1000 mL distilled water of 70'C for 3.5 minutes. The residue was removed using a metal mesh of 150 mesh. This extraction liquid was rapidly cooled to room temperature in ice water, and subjected to centrifugal isolation (700 rpm, 10 minutes) treatment with use of SAl continuous centrifugal isolator manufactured by Westphalia, and the insoluble fraction was removed. Then, the extraction liquid was added with L-ascorbic acid to 300 ppm 64 with respect to the blend mass-up amount (1000 mL), and adjusted to pH 6.0 with sodium bicarbonate. This blend fluid was UHT-sterilized for 30 seconds in a range of 133'C to 135'C. This blend was filled into a PET bottle, and cooled to room temperature (about 25'C) in flowing water, whereby to prepare Tea beverages 1 to 7. These tea beverages 1 to 7 were stored at 25 0 C for 5 months, and sensory evaluations were performed using them. [0084) Evaluations for the aroma, the nutritious taste, and the temporal stability were performed by 7 specialist panelists. In addition, the evaluation was conducted by giving any score of the 1 to 4 points described below, where 3.5 or more of the average points of the 7 panelists was indicated as "@ (double circle)", 3 or more and less than 65 3.5 was indicated as "0 (circle)", and 2 or more and less than 3 was indicated as "A (triangle)", and less than 2 was indicated as "x (cross)". In addition, as the total evaluation, the average points of the aroma, the nutritious taste, and the temporal stability were calculated, and evaluations were conducted similarly to those described above. These test results are listed in described below Table 8. [0085] <Aroma> 4 Points = Very strong 3 Points = Strong 2 Points = Somewhat weak 1 Point = Weak [0086] <Nutritious taste> 66 4 Points = Very good 3 Points = Good Comment: "2" (7)% 3 Points = Somewhat poor 1 Point = Poor [0087] <Temporal stability> 4 Points = Very high 3 Points = high 2 Points = Somewhat low 1 Point = low [0088] [Table 8] Form Evaluation Aracha Aracha Aracha Aracha Aracha Aracha Aracha Item tea 1 tea 2 tea 3 tea 4 tea 5 tea 6 tea 7 Sucrose/bitt er taste 0.43 0.54 0.83 1.38 2.10 2.21 1.15 Aracha component tea Weight of catechin (% 13.8 12.5 11.5 14.5 13.3 13.5 12.5 by weight) Tea Tea Tea Tea Tea Tea Tea Beverag Beverag Beverag Beverag Beverag Beverag Beverag e 1 e 2 e 3 e 4 e 5 e 6 e 7 67 Fresh aroma x 0 0 0 0 Nutritious Bevera taste 0 O O ge packed in a contai ner Temporal A stability Total A A evaluation [0089] (Results of Test 5) It was found out that if the value of the sucrose/bitter taste component of the Aracha tea became 0.43 or 2.21, results of the sensory evaluations were somewhat poor. From these results, it was found out that 68 the value of the sucrose/bitter taste component is suitably in a range of 0.45 to 2.15. [0090] <Test 6> Tea leaves after being subjected to the treatments A to C described below, were subjected to rolling treatment and drying treatment in a similar manner to conventional one, and an Aracha tea was prepared for every treatment and every tea season, respectively. Then, Aracha teas 8 to 14 were prepared according to Table 9, and extracted, whereby to prepare Tea beverages 8 to 14, and the sensory evaluations were performed. First, the weight of the cuticle layer and the weight of fiber of the tea leaves of each tea season after being subjected to the treatments A to C were measured, respectively before preparing the Aracha teas, and the 69 value of the cuticle layer/fiber as listed in Table 10 was calculated. [0091] (Treatment A) Steaming treatment was performed with respect to live tea leaves in a similar manner to conventional one. [0092] (Treatment B) 10 L warm water of 100'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated at about 120 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into the container, and subjected for 90 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was 70 performed three times, and the obtained 450 g in total of the tea leaves was subjected to steaming treatment in a similar manner to conventional one. [0093] (Treatment C) 10 L warm water of 90'C was retained in a cylindrical container having about 30 cm of the diameter, and this warm water was stirred by rotation so as to cause turbulence using a stirring machine, and circulated at about 120 m/minute of the flow rate. A metal mesh put in with 150 g of the tea leaves was put into the container, and subjected for 30 seconds. Then, the tea leaves were recovered, and lightly washed out with tap water. This manipulation was performed three times, and the obtained 450 g in total of the tea leaves was subjected to steaming treatment in a similar manner to conventional one.

71 [0094] (Blend) The Aracha teas obtained by performing the treatments A to C were blended in the ratio as listed in Table 9 described below, whereby to prepare Aracha teas 8 to 14. [00951 [Table 9] Aracha Aracha Aracha Aracha Aracha Aracha Aracha tea 8 tea 9 tea 10 tea 11 tea 12 tea 13 tea 14 First First First Third Third Third Second Tea flush flush flush flush flush flush flush season tea tea tea tea tea tea tea Treatment 90 70 50 70 30 10 0 A (%) Treatment 10 30 50 30 70 90 0 B (%) Treatment 0 0 0 0 0 0 100 C (%) [0096] (Analysis Test) The weight of sucrose, the weight of caffeine, and the weight of oxalic acid of the Aracha teas 8 to 14 were measured, and the ratio of the weight of sucrose relative 72 to the weight of caffeine and the weight of oxalic acid (the weight of bitter taste components) (sucrose/bitter taste component) was calculated. These results are listed in Table 10 described below. [0097] (Sensory evaluation) 10 g of the Aracha teas 8 to 14 was taken, and extracted with 1000 mL distilled water of 70'C for 3.5 minutes. The residue was removed using a metal mesh of 150 mesh. This extraction liquid was rapidly cooled to room temperature in ice water, and subjected to centrifugal isolation (700 rpm, 10 minutes) treatment with use of SAl continuous centrifugal isolator manufactured by Westphalia, and the insoluble fraction was removed. Then, the extraction liquid was added with L-ascorbic acid to 300 ppm with respect to the blend mass-up amount (1000 mL), and 73 adjusted to pH 6.0 with sodium bicarbonate. This blend fluid was UHT-sterilized for 30 seconds in a range of 133'C to 135'C. This blend was filled into a PET bottle, and cooled to room temperature (about 25'C) in flowing water, Comment: " Mzf 8 -1I and whereby to prepare Tea beverages 1 to 7|. These tea beverages 8 to 14 were stored at 25 0 C for 5 months, and the sensory evaluations were performed using them. [0098] Evaluations for the aroma, the nutritious taste, and the temporal stability were performed by 7 specialist panelists. In addition, the evaluations were conducted similarly to Test 5 described above. These test results are listed in Table 10 described below. [0099] [Table 10] Form Evaluation Aracha Aracha Aracha Aracha Aracha Aracha Aracha 74 Item tea 8 tea 9 tea 10 tea 11 tea 12 tea 13 tea 14 Sucrose/bit Aracha tea ter taste 0.36 0.90 1.11 0.71 1.80 2.45 1.59 component Live Cuticle 3.23 2.81 2.34 1.89 0.51 0.42 1.76 leaves layer/fiber Tea Tea Tea Tea Tea Tea Tea Bevera Bevera Bevera Bevera Bevera Bevera Bevera ge 8 ge 9 ge 10 ge 11 ge 12 ge 13 ge 14 Fresh aroma 0 0 0 0 0 Nutritious A Bevera taste O O O o ge packed in a contai ner Temporal A stability Total A A .o o © o evaluation [0100] (Results of Test 6) It was found out that if the value of the cuticle layer/fiber of the tea leaf became 0.42 or 3.23, results of 75 the sensory evaluations were somewhat poor. From these results, it was found out that the value of the cuticle layer/fiber is suitably in a range of 0.45 to 3.00.

Claims (5)

1. A method of producing a raw tea material for use in making a beverage, the method comprising treating tea leaves to reduce the cuticle layer of the tea leaves, wherein the method includes the steps of contacting the tea leaves with flowing water at a temperature of between 60 0 C to 100 0 C and a flow rate of 20 m/minute to 120 m/minute, for between 10 seconds to 120 seconds, whereby the ratio of the weight of the cuticle layer relative to the weight of fiber of the tea leaves obtained by treating the raw tea material by the method is 0.45 to 3.00.

2. The method of producing a raw tea material according to claim 1, wherein the flowing water is contacted with either one or both faces of the leaves in an approximately horizontal flow with respect to the leaves faces.

3. The method of producing a raw tea material according to claim 1 or 2, wherein the raw tea material has a ratio of the weight of sucrose relative to the weight of bitter taste components, comprising oxalic acid and caffeine, of 0.45 to 2.15. 77

4. A tea beverage containing an extraction liquid obtained from the raw tea material produced by the method of any one of claims 1 to 3.

5. A method of reducing the cuticle layer of tea leaves, the method comprising contacting the tea leaves with flowing water at a temperature of between 60 0 C to 100 0 C and at a flow rate of between 20 m/minute to 120 m/minute, for a period of between 10 seconds to 120 seconds, whereby the resultant treated tea leaves have a ratio of the weight of the cuticle layer relative to the weight of fiber of the tea leaves of 0.45 to 3.00. ITO EN LTD WATERMARK PATENT AND TRADE MARKS ATTORNEYS P3G245AU00