Process for producing purified tea extract

Abstract

Provided is a process for producing a tea extract having a high recovery rate of non-polymer catechins, a low caffeine content and an improved taste and color tone. As one embodiment of this invention provides, there is provided a process for producing a purified tea extract by adsorbing a tea extract on a synthetic adsorbent, bringing an aqueous solution of an organic solvent or a basic aqueous solution into contact with the synthetic adsorbent to elute non-polymer catechins, and then bringing the eluate into contact with activated carbon in an aqueous solution of an organic solvent.

Claims

1. A process for producing a purified tea extract, comprising adsorbing a tea extract on a synthetic adsorbent, washing the synthetic adsorbent with a basic aqueous solution or ethanol at a solvent concentration of from 0 to 5 wt %, contacting the synthetic adsorbent with ethanol at a solvent concentration of from 10 to 80 wt % to elute non-polymer catechins, and then bringing the eluate into contact with activated carbon in ethanol, wherein the synthetic adsorbent is an acrylic resin, methacrylic resin, polyvinyl resin or styrene resin.

2. A process for producing a purified tea extract, comprising adsorbing a tea extract on a synthetic adsorbent, eluting said tea extract with a basic aqueous solution by contacting the synthetic adsorbent with said basic aqueous solution to elute non-polymer catechins, adjusting the pH of the eluate to 7 or lower, concentrating the eluate, and then subjecting the eluate to solid-liquid separation to remove precipitated and suspended matters, wherein the synthetic adsorbent is an acrylic resin, methacrylic resin, polyvinyl resin or styrene resin.

3. A process for producing a purified tea extract, comprising adsorbing a tea extract on a synthetic adsorbent, washing the synthetic adsorbent with ethanol at a solvent concentration of from 0 to 5 wt %, and then contacting the synthetic adsorbent with a basic aqueous solution or ethanol at a solvent concentration of from 10 to 80 wt % to fractionate a tea extract having a percentage of non-gallates as non-polymer catechins in a range of from 55 to 100 wt % and a caffeine/non-polymer catechins of from 0 to 0.15, wherein the synthetic adsorbent is an acrylic resin, methacrylic resin, polyvinyl resin or styrene resin.

4. The process according to claim 1, wherein the tea extract undergoes a hydrolysis treatment.

5. The process according to claim 1, wherein subsequent to completion of the adsorption step, the synthetic adsorbent is washed, and the basic aqueous solution or ethanol is then brought into contact with the synthetic adsorbent.

6. The process according to claim 1, wherein the synthetic adsorbent is contacted with ethanol.

7. The process according to claim 1, wherein the resulting purified tea extract comprises from 25 to 90 wt % of non-polymer catechins based on its solid content.

8. The process according to claim 1, wherein the resulting purified tea extract comprises from 25 to 90 wt % of non-polymer catechins based on its solid content, and has a ratio of caffeine to non-polymer catechins in a range of from 0 to 0.15.

9. The process according to claim 1, wherein the resulting purified tea extract comprises from 25 to 90 wt % of non-polymer catechins based on its solid content, a ratio of caffeine to said non-polymer catechins is from 0 to 0.15, a percentage of gallates in said non-polymer catechins is from 0 to 70 wt %, and a ratio of gallic acid to the non-polymer catechins is from 0 to 0.1.

10. The process according to claim 4, wherein the hydrolysis treatment is treatment with an enzyme, cells or culture having tannase activity.

11. The process according to claim 2, wherein the tea extract undergoes a hydrolysis treatment.

12. The process according to claim 11, wherein the hydrolysis treatment is treatment with an enzyme, cells or culture having tannase activity.

Description

EXAMPLES

(1) Measurements of Catechins, Caffeine and Gallic Acid

(1) A high-performance liquid chromatograph (model: “SCL-10AVP”) manufactured by Shimadzu Corporation was used. The chromatograph was fitted with a liquid chromatograph column packed with octadecyl-introduced silica gel, “L-Column, TM ODS” (4.6 mm in diameter×250 mm; product of Chemicals Evaluation and Research Institute, Japan). A sample solution was filtered through a filter (0.45 μm), and then subjected to chromatography at a column temperature of 35° C. by the gradient elution method. A solution A, mobile phase, was a solution containing acetic acid at 0.1 mol/L in distilled water, while a solution B, mobile phase, was a solution containing acetic acid at 0.1 mol/L in acetonitrile. The measurement was conducted under the conditions of 20 μL sample injection volume and 280 nm UV detector wavelength.

(2) Assessment of Tastes of Purified Products of Tea Extracts

(2) The purified tea extract obtained in each Example was diluted with deionized water such that the content of non-polymer catechins dropped to 0.175% [w/v], and an aliquot (40 mL) of the diluted extract was placed in a 50-mL pressure-resistant glass vessel. Sodium ascorbate (0.1 wt %) was added to the diluted extract, and its pH was adjusted to 6.4 with a 5% aqueous solution of sodium bicarbonate. After having been purged with nitrogen, the pH-adjusted extract was subjected to thermal sterilization at 121° C. for 10 minutes in an autoclave. Subsequently, its bitterness was assessed by a panel of five assessors with respect to a foretaste and an aftertaste. The assessment of bitterness was performed by the quinine sulfate method.

(3) Assessment of Bitterness by the Quinine Sulfate Method

The Equivalent Concentration Test Method

(3) Quinine sulfate dihydrate was adjusted to concentrations corresponding to the bitterness intensities shown in the table. After each assessment sample was tasted, a determination was made concerning to which sample of standard bitterness solutions the intensity of bitterness was equal. The intensity of bitterness was confirmed by the panel of five assessors. (References: Newly-edited “Organoleptic Test Handbook” in Japanese, PP 448-449, Organoleptic Test Committee, Union of Japanese Scientists and Engineers; Perception & Psychophysics, 5, pp. 347-351, 1696).

(4) TABLE-US-00001 TABLE 1 Concentrations of Standard Bitter Solutions Quinine sulfate dihydrate Bitterness intensity (g/100 mL, aq.) 1 0.00023 2 0.00050 3 0.00094 4 0.00157 5 0.00241 6 0.00388 7 0.00608 8 0.00985 9 0.01572 10 0.02568

(4) Measurement of Color Tone

(5) Using a HITACHI spectrophotometer (Model: U-2001) each membrane-filtered product of green tea extract was diluted with deionized water in a glass cell to provide an aqueous solution in which the concentration of non-polymer catechins was 1 wt %, and was then measured. The measurement wavelength of the spectrophotometer at the time of the analysis was set at 450 nm.

Example 1

(6) Hot water of 88° C. (45 kg) was added to green tea leaves (produce of Kenya, large leaf variety; 3 kg). After batchwise extraction for 60 minutes under stirring, coarse filtration was conducted through a 100-mesh screen. To remove fine powder from the extract, a centrifugal separation operation was then performed to obtain a “green tea extract” (37.2 kg, pH 5.4) (the concentration of non-polymer catechins in the green tea extract=0.89 wt %, the percentage of gallates in the green tea extract=52.3 wt %, caffeine: 0.17 wt %). The green tea extract was held at the temperature of 15° C., and tannase (“TANNASE KTFH”, product of Kikkoman Corporation; 500 U/g) was then added to the green tea extract to give a concentration of 430 ppm. The solution was held for 55 minutes. When the percentage of gallates had dropped to 30.5 wt %, the solution was heated to 90° C., at which the solution was held for 2 minutes to inactivate the enzyme so that the reaction was terminated (pH 5.1). Under the conditions of 70° C. and 6.7 kPa, concentration processing was performed to a Brix concentration of 20% by reduced-pressure concentration. Further, the concentrate was spray-dried to obtain a powdery “tannase-treated green tea extract” (0.9 kg). The thus-obtained green tea extract had the following data the content of non-polymer catechins: 27.8 wt %, the percentage of non-polymer catechingallates: 30.3 wt %, the content of caffeine: 6.74 wt %, and gallic acid: 3.58 wt %. The “tannase-treated green tea extract” (285 g) was dissolved under stirring at 25° C. for 30 minutes in deionized water (8,550 g) (tannase-treated solution).

(7) Next, a synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 2,209 mL) was packed in a stainless steel column 1 (110 mm inner diameter×230 mm height, volume: 2,185 mL). An ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 852 mL) was packed in a stainless steel column (38 mm inner diameter×770 mm height, volume: 877.4 mL). On each of the columns, 95 (v/v) ethanol (4 volumes relative to the packed resin) was loaded beforehand at SV=5 (h.sup.−1), followed by the loading of water (10 volumes relative to the packed resin) to wash the column. Subsequently, the tannase-treated solution (8,835 g, 4 volumes relative to the synthetic adsorbent) obtained as described above was loaded at SV=1 (h.sup.−1) on the column 1 and the outflow was discarded. The column 1 was then washed at SV=2 (h.sup.−1) with water (2,209 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 0.1 wt % aqueous solution of sodium hydroxide (pH 12.4; 13,256 mL, 6 volumes relative to the synthetic adsorbent) was loaded at SV=5 (h.sup.−1). The eluate was continuously loaded on the column 2 to effect deionization, so that a non-polymer catechin composition (13,080 g; pH 3.3) was obtained. Non-polymer catechins were contained at 0.38 wt % in the extract, and the percentage of gallates in the non-polymer catechin composition was 28.6 wt %. Further, caffeine was 0 wt %, and the amount of gallic acid was 0.002 wt %. Non-polymer catechins in the solid content of the tea extract amounted to 69.0 wt %. Reduced-pressure concentration was then conducted under the conditions of 40° C. and 2.6 kPa to a non-polymer catechin concentration of 6% (turbidity: 208 NTU). The thus-concentrated tea extract was then caused to pass through a 0.8-μm cellulose acetate membrane (“ADVANTEC: C080A090C), and by solid-liquid separation, the tea extract was separated from suspended matters to obtain a “resin-treated product 1” (turbidity: 1.5 NTU). Granular activated carbon “TAIKO SGP” (product of Futamura Chemical Co., Ltd.; 6.5 g) was then packed in a stainless steel column 3 (22 mm inner diameter×145 mm height, volume: 55.1 mL). The “resin-treated product 1” was formed into a solution such that the concentration of non-polymer catechins and the concentration of ethanol become 4% and 20 wt %, respectively. An aliquot (267 g) of the solution was loaded at SV=2 (h.sup.−1) on the column 3 (the amount of the activated carbon was 0.6 times relative to the amount of non-polymer catechins). Subsequently, filtration was conducted through a 0.2-μm membrane filter. Finally, deionized water (50 g) was added, ethanol was distilled off under the conditions of 40° C. and 2.7 kPa, and then, the water content was adjusted to obtain an “activated-carbon-treated product 1” (2.1 NTU). Non-polymer catechins were contained at 13.7 wt % in the extract, and the percentage of gallates in the non-polymer catechin composition was 23.5 wt %. Further, caffeine was 0 wt %, and the amount of gallic acid was 0.054 wt %. Non-polymer catechins in the solid content of the tea extract amounted to 79.6 wt %.

Comparative Example 1

(8) The “resin-treated product 1” in Example 1.

Example 2

(9) A synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 2,048 mL) was packed in a stainless steel column 4 (110 mm inner diameter×230 mm height, volume: 2, 185 mL). The column was washed beforehand in a similar manner as in Example 1. The tannase-treated solution (8,191 g, 4 volumes relative to the synthetic adsorbent) obtained in Example 1 was loaded at SV=1 (h.sup.−1) on the column 4 and the outflow was discarded. The column 4 was then washed at SV=2 (h.sup.−1) with water (2,048 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 20 wt % aqueous solution of ethanol (12,287 mL, 6 volumes relative to the synthetic adsorbent) was loaded at SV=2 (h.sup.−1) to obtain a non-polymer catechin composition (12,090 g; pH 2.1). Non-polymer catechins were contained at 0.51 wt % in the extract, and the percentage of gallates in the non-polymer catechin composition was 27.4 wt %. Further, caffeine was 0.075 wt %, and the amount of gallic acid was 0.002 wt %. Non-polymer catechins in the solid content of the tea extract amounted to 62.5 wt %. Reduced-pressure concentration was then conducted at 40° C. and 2.7 kPa to distill off ethanol, and then, the water content was adjusted to obtain a “resin-treated product 2”. Subsequently, it was subjected to treatment in contact with activated carbon in a similar manner as in Example 1 (the amount of the activated carbon was 0.6 times relative to the non-polymer catechins) to obtain a “activated-carbon-treated product 2” (1.7 NTU). Non-polymer catechins were contained at 15.0 wt % in the extract, and the percentage of gallates in the non-polymer catechin composition was 20.9 wt %. Further, caffeine was 0.264 wt %, and the amount of gallic acid was 0.057 wt %. Non-polymer catechins in the solid content amounted to 72.8 wt %.

Comparative Example 2

(10) The “resin-treated product 2” in Example 2.

(11) The results of comparisons between Example 1 and Comparative Example 1 and between Example 2 and Comparative Example 2 are shown in Table 2.

(12) TABLE-US-00002 TABLE 2 Reaction conditions, test items and results Comp. Comp. of organoleptic assessments Example 1 Ex. 1 Example 2 Ex. 2 Hydrolysis treatment Applied Applied Applied Applied Percentage of gallates in non-polymer [wt %] 27.8 27.8 27.8 27.8 catechins in hydrolysis-treated product (product before resin treatment) Separation method from resin [wt %] Aq. NaOH Aq. NaOH Aq. EtOH Aq. EtOH soln. soln. soln. soln. Concentration of aqueous solution of organic [wt %] 20 — 20 — solvent upon bringing into contact with activated carbon Non-polymer catechins [wt %] 13.7 6.0 15.0 6.0 Non-polymer catechins in solid content [wt %] 79.6 69.0 72.8 62.5 Percentage of gallates in non-polymer [wt %] 23.5 28.6 20.9 27.4 catechins Caffeine [wt %] 0.000 0.000 0.264 0.882 Gallic acid [wt %] 0.054 0.032 0.057 0.024 Bitterness in foretaste 5.0 5.0 5.0 5.0 Bitterness in aftertaste 5.0 5.5 5.0 5.3 Color tone (450 nm) 0.23 2.78 0.35 2.15

(13) As evident from Table 2, a purified tea extract having a lowered caffeine content, an aftertaste with reduced bitterness and an improved color tone lowered in caffeine, reduced in the bitterness of aftertaste and improved in color tone can be obtained by adsorbing a tea extract on a synthetic adsorbent, conducting elution with an aqueous solution of an organic solvent or a basic aqueous solution and then treating the eluate in an aqueous solution of an organic solvent. The extract is, therefore, useful not only as a tea-based beverage but also as a non-tea-based beverage.

Examples 3-6

(14) Following the procedure of Example 1, operations were performed without any hydrolysis treatment and also by conducting hydrolysis treatment until the percentage of gallates became about 3.5% and setting the concentration of the aqueous solution of the organic solvent at 20 wt % and 60 wt %, respectively, upon bringing into contact with the activated carbon (the amount of the activated carbon was 0.6 times relative to non-polymer catechins). The results are shown in Table 3.

(15) TABLE-US-00003 TABLE 3 Reaction conditions, test items and results of organoleptic assessments Example 3 Example 4 Example 5 Example 6 Hydrolysis treatment Not Not Applied Applied applied applied Percentage of gallates in non-polymer [wt %] 55.8 54.3 3.5 3.4 catechins in hydrolysis-treated product (product before resin treatment) Separation method from resin [wt %] Aq. NaOH Aq. NaOH Aq. NaOH Aq. NaOH soln. soln. soln. soln. Concentration of aqueous solution of organic [wt %] 20 60 20 60 solvent upon bringing into contact with activated carbon Percentage of gallates in non-polymer [wt %] 53.2 53.9 1.1 2.1 catechins Color tone (450 nm) 0.22 0.31 0.42 0.74 Recovery rate from treatment with activated [wt %] 69 79 73 81 carbon

(16) Comparing the cases of 20 wt % with the cases of 60 wt % as the concentration of an aqueous solution of an organic solvent upon bringing into contact with activated carbon in Table 3, 20 wt % is preferred in color tone but 60 wt % is preferred in recovery rate.

Examples 7-9, Comparative Examples 3-4

(17) The procedures of Example 1 and Example 2 were followed except that the concentration of the aqueous solution of the organic solvent upon bringing into contact with the activated carbon was set at 0 wt %, 7.5 wt % and 20 wt % and the contacting operation with the activated carbon was conducted by the stirring tank method (the amount of the activated carbon was 0.6 times relative to the amount of non-polymer catechins). The results are shown in Table 4.

(18) TABLE-US-00004 TABLE 4 Reaction conditions, test items and results of organoleptic Comp. Comp. assessments Example 7 Example 8 Ex. 3 Example 9 Ex. 4 Hydrolysis treatment Applied Applied Applied Applied Applied Percentage of gallates in [wt %] 27.1 28.2 27.2 26.8 26.8 non-polymer catechins in hydrolysis-treated product (product before resin treatment) Separation method from resin [wt %] Aq. NaOH Aq. NaOH Aq. NaOH Aq. EtOH Aq. EtOH soln. soln. soln. soln. soln. Concentration of aqueous [wt %] 7.5 20 0 20 0 solution of organic solvent upon bringing into contact with activated carbon Percentage of gallates in [wt %] 21.2 24.1 19.4 22.6 15.6 non-polymer catechins Color tone (450 nm) 0.48 0.43 0.86 0.61 0.97 Recovery rate from treatment [wt %] 78 75 68 71 60 with activated carbon

(19) As evident from Table 4, the tone and recovery rate are better in the case that the concentration of an aqueous solution of an organic solvent upon bringing into contact with activated carbon is set at 7.5 wt % or 20 wt % in comparison with the case that the concentration of an aqueous solution of an organic solvent upon bringing into contact with activated carbon is set at 0 wt % (water is used as a solvent).

Example 10

(20) Using the “activated-carbon-treated product 1” of Example 1, the beverage described in Table 5 was prepared for packaging application. Under the Food Sanitation Act of Japan, the beverage was subjected to sterilization treatment and then to hot-pack filling so that a packaged beverage was produced.

(21) After the thus-produced packaged beverage was stored at 37° C. for 30 days, it was assessed. It was good in external appearance and the stability of taste.

(22) TABLE-US-00005 TABLE 5 Added Names of materials amounts (g) Sugar 1.50 Salt 0.33 Sweetener 0.01 VC 0.05 Fruit juice 0.10 Flavor 0.20 Catechin preparation 1.28 (Example 1) Deionized water Balance Total 100.00

Example 11

(23) A crude catechin preparation (product of Mitsui Norin Co., Ltd., the concentration of non-polymer catechins=32.0 wt %, the percentage of non-polymer catechingallates=52.2 wt %, caffeine=5.88 wt %; 150 g) was dissolved at 25° C. for 30 minutes under stirring in deionized water (4,500 g) to obtain a green tea extract solution (pH 5.3). Next, a synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 861 mL) packed in a stainless steel column 1 (60 mm inner diameter×360 mm height, volume: 1,017.4 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (3,444 mL), and then at SV=5 (h.sup.−1) with water (8,610 mL). An ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 350.6 mL) packed in a stainless steel column 2 (38 mm inner diameter×340 mm height, volume: 385.4 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (1402.4 mL), and then at SV=5 (h.sup.−1) with water (3,506 mL). Subsequently, the green tea extract solution (3,435 g, 4 volumes relative to the synthetic adsorbent) was loaded at SV=1 (h.sup.−1) on the stainless steel column 1 and the outflow was discarded. The column 1 was then washed at SV=2 (h.sup.−1) with water (861 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 0.1 wt % aqueous solution of sodium hydroxide (pH 12.5; 12,900 mL, 15 volumes relative to the synthetic adsorbent) was loaded at SV=5 (h.sup.−1) to obtain a non-polymer catechin eluate. The eluate was continuously loaded on the stainless steel column 2 to conduct deionization, so that a non-polymer catechin composition (12,860 g, pH 3.5) was obtained. Non-polymer catechins were contained at 0.24 wt % in the composition, the recovery rate of non-polymer catechins from the tea extract solution was 92.4%, and the percentage of gallates in the non-polymer catechin composition was 52.9 wt %. Further, caffeine was 0 wt %. The amount of non-polymer catechins in the solid content of the tea extract was 69.2 wt %. By reduced-pressure concentration, then on-polymer catechin composition was subjected at 40° C. and 2.6 kPa to concentration processing to a non-polymer catechin concentration of 6% (turbidity: 322 NTU), so that a “concentrated green tea extract 1” was obtained. Centrifugal separation (8,000 r/min) was then conducted at 25° C. for 15 minutes, and by solid-liquid separation, the tea extract was separated from suspended matters to obtain a “purified green tea extract 1” (turbidity: 39.5 NTU).

Example 12

(24) The “concentrated green tea extract 1” obtained in Example 11 was caused to pass through a 0.8-μm cellulose acetate membrane (“ADVANTEC: C080A090C) to separate suspended matters, so that a “purified green tea extract 2” (turbidity: 1.8 NTU) was obtained.

Example 13

(25) Hot water of 88° C. (45 kg) was added to green tea leaves (produce of Kenya, large leaf variety; 3 kg). After batchwise extraction for 60 minutes under stirring, coarse filtration was conducted through a 100-mesh screen. To remove fine powder from the extract, a centrifugal separation operation was then performed to obtain a “green tea extract” (37.2 kg, pH 5.4) (the concentration of non-polymer catechins in the green tea extract=0.89 wt %, the percentage of gallates in the green tea extract=52.3 wt %, caffeine: 0.17 wt %).

(26) The green tea extract was held at the temperature of 15° C., and tannase (“TANNASE KTFH”, product of Kikkoman Corporation; 500 U/g) was then added to the green tea extract to give a concentration of 430 ppm. The solution was held for 55 minutes. When the percentage of gallates had dropped to 30.5 wt %, the solution was heated to 90° C., at which the solution was held for 2 minutes to inactivate the enzyme so that the reaction was terminated (pH 5.1). Under the conditions of 70° C. and 6.7 kPa, concentration processing was performed to a Brix concentration of 20%. Further, the concentrate was spray-dried to obtain a powdery “tannase-treated green tea extract” (0.9 kg). The thus-obtained green tea extract had the following data—the content of non-polymer catechins: 27.8 wt %, the percentage of non-polymer catechingallates: 30.3 wt %, and the content of caffeine: 6.74 wt %. The “tannase-treated green tea extract” (10 g) was dissolved under stirring at 25° C. for 30 minutes in deionized water (300 g) (tannase-treated solution).

(27) Next, a synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 36.1 mL) packed in a stainless steel column 3 (22 mm inner diameter×96 mm height, volume: 36.5 mL) was washed beforehand in a similar manner as in Example 1, and an ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 14.7 mL) packed in a glass column (16 mm inner diameter×80 mm height, volume: 16.1 mL) was washed beforehand in a similar manner as in Example 1. The tannase-treated solution (144.4 g, 4 volumes relative to the synthetic adsorbent) obtained as described above was loaded at SV=1 (h.sup.1) on the stainless steel column 3 and the outflow was discarded. The column 3 was then washed at SV=2 (h.sup.−1) with water (36.1 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 0.1 wt % aqueous solution of sodium hydroxide (pH 12.4; 561.8 mL, 15 volumes relative to the synthetic adsorbent) was loaded at SV=5 (h.sup.−1). The eluate was continuously loaded on the glass column to conduct deionization, so that a non-polymer catechin composition (552 g, pH 2.7) was obtained. Non-polymer catechins were contained at 0.21 wt % in the extract, the recovery rate of non-polymer catechins from the tannase-treated solution was 90.3%, and the percentage of gallates in the non-polymer catechin composition was 32.5 wt %. Further, caffeine was 0 wt %. The amount of non-polymer catechins in the solid content of the tea extract was 64.7 wt %. By reduced-pressure concentration, the non-polymer catechin composition was subjected at 40° C. and 2.6 kPa to concentration processing to a non-polymer catechin concentration of 6% (turbidity: 618 NTU), so that a “concentrated green tea extract 2” was obtained. The “concentrated green tea extract 3” was then caused to pass through a 0.8-μm cellulose acetate membrane (“ADVANTEC: C080A090C) to separate suspended matters by solid-liquid separation, so that a “purified green tea extract 3” (turbidity: 1.5 NTU) was obtained.

Comparative Example 5

(28) The “concentrated green tea extract 1” before the clarification in Example 11.

Comparative Example 6

(29) By a similar procedure as in Comparative Example 5 except that the amount of the ion-exchange resin was changed to ¼ and the pH value of the non-polymer catechin composition after the pH adjustment with the basic desorption solution was 9.1, a “concentrated green tea extract 3” was obtained.

(30) TABLE-US-00006 TABLE 6 Example 11 Example 12 Example 13 Comp. Ex. 5 Comp. Ex. 6 <Analysis data of feed solution> Content of non-polymer catechins [wt %] 0.98 0.98 0.89 0.98 0.98 Content of caffeine [wt %] 0.18 0.18 0.22 0.18 0.18 Percentage of non-polymer catechingallates [wt %] 52.2 52.2 30.3 52.2 52.2 <Analysis data after elution from synthetic adsorbent(desorbing solution)> Kind of synthetic adsorbent SP70 SP70 SP70 SP70 SP70 pH of alkaline aqueous solution [-] 12.5 12.5 12.4 12.5 12.6 Concentration of ethanol [wt %] — — — — — Content of non-polymer catechins [wt %] 0.24 0.24 0.21 0.24 0.17 Content of caffeine [wt %] 0 0 0 0 0 Caffeine/non-polymer catechins ratio [-] 0 0 0 0 0 Recovery rate of non-polymer catechins [%] 92.4 92.4 90.3 92.4 78.2 pH adjustment method Ion Ion Ion Ion Ion exchange exchange exchange exchange exchange (amount: ¼) pH after adjustment [-] 3.0 3.0 2.7 3.0 9.1 Proportion of gallates in purified product [wt %] 52.9 52.9 32.5 52.9 54.2 Non-polymer catechins in solid content [wt %] 69.2 69.2 64.7 69.2 50.2 Turbidity before clarification [NTU] 322 322 618 322 0.55 Turbidity after clarification [NTU] 39.5 1.8 1.5 — — <Assessment of flavor and taste after Bitterness Bitterness Bitterness Bitterness Bitter Bitter sterilization> reduced reduced reduced Refreshing Felt Felt Felt Not felt Not felt sensation Coarse No abnormal No abnormal No abnormal No abnormal Some abnormal taste taste or taste or taste or taste or taste and smell smell smell smell smell <Assessment of bitterness> Quinine 7.5 7.5 5.5 7.8 7.9 sulfate assessment Stability of color tone 450 [nm] 1.11 1.08 1.21 660 [nm] 0.05 0.05 0.14 670 [nm] 0.05 0.04 0.13 800 [nm] 0.02 0.01 0.08

Example 14

(31) Using the “purified tea extract 2” of Example 12, the beverage described in Table 7 was prepared for packaging application. Under the Food Sanitation Act of Japan, the beverage was subjected to sterilization treatment and then to hot-pack filling so that a packaged beverage was produced.

(32) After the thus-produced packaged beverage was stored at 37° C. for 30 days, it was assessed. It was good in external appearance and the stability of taste.

(33) TABLE-US-00007 TABLE 7 Formulation (wt %) Names of materials Sugar 1.50 Salt 0.33 Sweetener 0.01 VC 0.05 Fruit juice 0.10 Flavor 0.20 Catechin preparation 2.11 (Example 12) Deionized water Balance Total 100.00

(34) Before and after the treatment in each of Examples 11 to 13, the recovery rate of non-polymer catechins was high, the concentration of caffeine had been lowered, and the purified green tea extract so obtained had improved taste and stability. In Example 14, the produced beverage was good in external appearance and the stability of taste. In Comparative Example 5, the bitterness and color tone were inferior, and in Comparative Example 6, bitterness and a coarse taste remained.

(35) (Measurement Method of Tannase Activity)

(36) Reagent A: citrate buffer solution (pH 5.5, 50 mmol)—Citric acid (10.5 g) is dissolved in distilled water (800 mL), and the solution is adjusted to pH 5.5 with 1N NaOH solution and is diluted to 1,000 mL.

(37) Reagent B: 0.35 wt % aqueous solution of substrate (tannic acid)—Tannic acid (175 mg) is dissolved in the citrate buffer solution (Reagent A, 50 mL).

(38) Reagent C: 90 vol % ethanol solution.

(39) Measuring Method:

(40) 1. The substrate solution (Reagent B, 1.0 mL) is placed in a test tube, and was maintained at 30° C. for 5 minutes. 2. A sample solution (0.25 mL) is added, and is cultured for 15 minutes at 30° C. To a blank solution, the citrate buffer solution (Reagent A) is added instead of the sample solution. 3. To the sample solution and blank solution, terminate the enzyme reaction, the ethanol solution (Reagent C, 5.0 mL each) is added to terminate the enzyme reaction. 4. Absorbance at 310 nm is measured (sample: A.sub.s, blank: A.sub.0).

(41) Activity is calculated in accordance with the following calculation equations.
Activity per volume (U/mL)=(A.sub.s−A.sub.0)×20.3×1.0 (mL)×1.04×df/(0.71×0.25 (mL)×15 (min))=ΔA×7.93×df
Activity per weight (U/g)=(U/mL)×1/C

(42) 20.3: μmol of tannic acid contained in 1.0 mL of the substrate solution (Reagent B) 0.71: a change in absorbance after the completion of the hydrolysis of tannic acid (20.3 μmol) under analysis conditions

(43) 1.04: conversion factor

(44) df: dilution factor

(45) C: concentration of tannase in sample (g/mL)

(46) (Assessment of Flavor and Taste after Sterilization)

(47) The tea extract obtained in each Example was dilute with deionized water such that the content of catechins was lowered to 0.175% [w/v]. An aliquot (40 mL) of the diluted tea extract was placed in a 50-mL pressure-resistant glass vessel. Sodium ascorbate (0.1 wt %) was added to the diluted tea extract. The solution was adjusted to pH 6.4 with a 5% aqueous solution of sodium bicarbonate, purged with nitrogen, and then subjected to thermal sterilization at 121° C. for 10 minutes in an autoclave. Subsequently, it was determined by a panel of 5 assessors as to whether or not any abnormal taste and/or smell derived from green tea was felt.

Example 15

(48) Hot water of 90° C. (27 kg) was added to green tea leaves (Yunnan Province, China; large leaf variety; 1.8 kg). After batchwise extraction for 30 minutes under stirring, coarse filtration was conducted through a 100-mesh screen. Subsequent to a centrifugal separation operation, filtration was conducted through No. 2 filter paper to obtain a “green tea extract” (20.4 kg, pH 5.3) (the concentration of non-polymer catechins in the green tea extract=0.96 wt %, the percentage of gallates in the green tea extract=69.5 wt %, caffeine: 0.24 wt %, gallic acid=0.01 wt %).

(49) The green tea extract was held at the temperature of 25° C., and tannase (“TANNASE KTFH”, product of Kikkoman Corporation; 500 U/g) was then added to the green tea extract to give a concentration of 300 ppm. The solution was held for 85 minutes. When the percentage of gallates had dropped to 52.4 wt %, the solution was heated to 90° C., at which the solution was held for 2 minutes to inactivate the enzyme so that the reaction was terminated (pH 4.8; tannase-treated solution (1)).

(50) Next, a synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 2,048 mL) packed in a stainless steel column 1 (110 mm inner diameter×230 mm height, volume: 2,185 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (8,192 mL), and then at SV=5 (h.sup.−1) with water (20,480 mL). An ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 852 mL) packed in a stainless steel column 2 (38 mm inner diameter×770 mm height, volume: 873 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (3,408 mL), and then at SV=5 (h.sup.−1) with water (8,520 mL). Subsequently, the tannase-treated solution (1) (8, 192 g, 4 volumes relative to the synthetic adsorbent) was loaded at SV=1 (h.sup.−1) on the column 1 and the outflow was discarded. The column 1 was then washed at SV=2 (h.sup.−1) with water (2,048 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 0.1 wt % aqueous solution of sodium hydroxide (pH 12.5; 30,720 mL, 15 volumes relative to the synthetic adsorbent) was loaded at SV=5 (h.sup.−1) to obtain a catechin eluate. The eluate was continuously loaded on the stainless steel column 2 to conduct deionization, so that a non-polymer catechin composition (28,222 g, pH 3.0) was obtained. Non-polymer catechins were contained at 0.24 wt % in the composition, the recovery rate of non-polymer catechins from the tannase-treated solution (1) was 92.9%, and the percentage of gallates in the non-polymer catechin composition was 55.3 wt %. Further, caffeine was 0 wt %, and the content of gallic acid was 0.001 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 62.4 wt %.

Comparative Example 7

(51) Tannase treatment was conducted as in Example 15, but the loading and elution on and from the synthetic adsorbent were not conducted.

Comparative Example 8

(52) Treatment was conducted in exactly the same manner as in Example 15 except for the omission of the tannase treatment.

Example 16

(53) (1) Hot water of 88° C. (45 kg) was added to green tea leaves (produce of Kenya, large leaf variety; 3 kg). After batchwise extraction for 60 minutes under stirring, coarse filtration was conducted through a 100-mesh screen. To remove fine powder from the extract, a centrifugal separation operation was then performed to obtain a “green tea extract” (37.2 kg, pH 5.4) (the concentration of non-polymer catechins in the green tea extract=0.89 wt %, the percentage of gallates in the green tea extract=52.3 wt %, caffeine: 0.17 wt %).

(54) The green tea extract was held at the temperature of 15° C., and tannase (“TANNASE KTFH”, product of Kikkoman Corporation; 500 U/g) was then added to the green tea extract to give a concentration of 430 ppm. The solution was held for 55 minutes. When the percentage of gallates had dropped to 30.5 wt %, the solution was heated to 90° C., at which the solution was held for 2 minutes to inactivate the enzyme so that the reaction was terminated (pH 5.1). Concentration processing was then performed at 70° C. and 6.7 kPa to a Brix concentration of 20% by reduced-pressure concentration. Further, the concentrate was spray-dried to obtain a powdery “tannase-treated green tea extract” (0.9 kg). The thus-obtained green tea extract had the following data—the content of non-polymer catechins: 27.8 wt %, the percentage of non-polymer catechingallates: 30.3 wt %, the content of caffeine: 6.74 wt %, and gallic acid: 3.58 wt %. The “tannase-treated green tea extract” (10 g) was dissolved under stirring at 25° C. for 30 minutes in deionized water (300 g) (tannase-treated solution (2)).

(55) Next, a synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 36.1 mL) packed in a stainless steel column 3 (22 mm inner diameter×96 mm height, volume: 36.5 mL) was washed beforehand in a similar manner as in Example 1, and an ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 14.7 mL) packed in a glass column (16 mm inner diameter 80 mm height, volume: 16.1 mL) was washed beforehand in a similar manner as in Example 1. The tannase-treated solution (2) (144.4 g, 4 volumes relative to the synthetic adsorbent) obtained as described above was loaded at SV=1 (h.sup.−1) on the column 1 and the outflow was discarded. The column 1 was then washed at SV=2 (h.sup.−1) with water (36.1 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 0.1 wt % aqueous solution of sodium hydroxide (pH 12.4; 561.8 mL, 15 volumes relative to the synthetic adsorbent) was loaded at SV=5 (h.sup.−1). The eluate was continuously loaded on the glass column to conduct deionization, so that a non-polymer catechin composition (552 g, pH 2.7) was obtained. Non-polymer catechins were contained at 0.21 wt % in the extract, the recovery rate of non-polymer catechins from the tannase-treated solution (2) was 90.3%, and the percentage of gallates in the non-polymer catechin composition was 32.5 wt %. Further, caffeine was 0 wt %, and the content of gallic acid was 0.002 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 64.7 wt %.

Example 17

(56) A crude catechin preparation (product of Mitsui Norin Co., Ltd., the concentration of non-polymer catechins=32.0 wt %, the percentage of non-polymer catechingallates=52.0 wt %, caffeine=5.51 wt %, gallic acid=0.17 wt %; 10 g) was dissolved at 25° C. for 30 minutes under stirring in deionized water (300 g) to obtain a green tea extract solution (pH5.3) Tannase (“TANNASE KTFH”, product of Kikkoman Corporation; 500 U/g) was then added to the green tea extract solution to give a concentration of 500 ppm. The solution was held at 15° C. for 120 minutes. When the percentage of gallates had dropped to 4 wt %, the solution was heated to 90° C., at which the solution was held for 2 minutes to inactivate the enzyme so that the reaction was terminated (pH 4.2; tannase-treated solution (3)).

(57) Under similar column and operation conditions as in Example 16 except that the raw material was the above-described tannase-treated solution, purification was conducted to obtain a non-polymer catechin composition (534.2 g, pH 3.7). Non-polymer catechins were contained at 0.18 wt % in the extract, the recovery rate of non-polymer catechins from the tannase-treated solution (3) was 91.3%, and the percentage of gallates in the non-polymer catechin composition was 6.0 wt %. Further, caffeine was 0 wt %, and the content of gallic acid was 0.004 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 57.6 wt %.

Example 18

(58) A synthetic adsorbent “SP-207” (product of Mitsubishi Chemical Corporation; 1,004 mL) packed in a stainless steel column 4 (60 mm inner diameter×360 mm height, volume: 1,017 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (4,016 mL), and then at SV=5 (h.sup.−1) with water (10,040 mL). An ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 1, 338 mL) packed in a stainless steel column 5 (38 mm inner diameter×1,200 mm height, volume: 1,360 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (5,352 mL), and then at SV=5 (h.sup.−1) with water (13,380 mL). The tannase-treated solution of Example 15 (4,016 g, 4 volumes relative to the synthetic adsorbent) was loaded at SV=1 (h.sup.−1) on the stainless steel column 4 and the outflow was discarded. The column 4 was then washed at SV=2 (h.sup.−1) with water (1,004 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 1 wt % aqueous solution of sodium hydroxide (pH 14.0; 5,020 mL, 5 volumes relative to the synthetic adsorbent) was loaded at SV=5 (h.sup.−1). The eluate was continuously loaded on the stainless steel column 5 to conduct deionization, so that a non-polymer catechin composition (4,975.5 g, pH 4.1) was obtained. Non-polymer catechins were contained at 0.63 wt % in the extract, the recovery rate of non-polymer catechins from the tannase-treated solution (1) was 88.2%, and the percentage of gallates in the non-polymer catechin composition was 58.3 wt %. Further, caffeine was 0 wt %, and the content of gallic acid was 0.001 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 59.3 wt %.

Example 19

(59) An operation was conducted as in Example 16 except the packed amount of the ion-exchange resin “SK1BH” was changed to 3.6 mL. Non-polymer catechins were contained at 0.17 wt % in the thus-obtained extract, the recovery rate of non-polymer catechins from the tannase-treated solution (2) was 78.2%, and the percentage of gallates in the non-polymer catechin composition was 35.8 wt %. Further, caffeine was 0 wt %, and the content of gallic acid was 0.001 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 43.3 wt %.

Comparative Example 9

(60) A synthetic adsorbent “SP-70” (product of Mitsubishi Chemical Corporation; 860 mL) packed in a stainless steel column 4 (60 mm inner diameter×360 mm height, volume: 1,017 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (3,440 mL), and then at SV=5 (h.sup.−1) with water (8,600 mL). The tannase-treated solution of Example 15 (3,440 g, 4 volumes relative to the synthetic adsorbent) was loaded at SV=1 (h.sup.−1) on the stainless steel column 4 and the outflow was discarded.

(61) The column 4 was then washed at SV=2 (h.sup.−1) with water (860 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 20 wt % aqueous solution of ethanol (5,160 mL, 6 volumes relative to the synthetic adsorbent) was loaded at SV=2 (h.sup.−1). Ethanol was distilled off at 40° C. and 2.7 kpa, and then, the water content was adjusted. In the thus-obtained extract, non-polymer catechins were contained at 0.50 wt %. The recovery rate of non-polymer catechins from the tannase-treated solution (1) was 84.4%, and the percentage of gallates in the non-polymer catechin composition was 45.9 wt %. Further, caffeine was 0.1 wt %, and the content of gallic acid was 0.008 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 60.8 wt %.

Comparative Example 10

(62) Acid clay (“MIZUKA ACE #600, product of Mizusawa Chemical Industries, Ltd.; 100 g) was dispersed at the stirring conditions of room temperature and 350 r/min in a 92.4 wt % aqueous solution of ethanol (800 g). After stirring was conducted for approximately 10 minutes, the tannase-treated green tea extract (200 g) obtained in Example 16 was poured, and still at room temperature, stirring was continued for approximately 3 hours (pH 4.0). Subsequently, the formed precipitate and acid clay were filtered off by No. 2 filter paper. The thus-obtained filtrate was brought into contact with activated carbon (“KURARAY COAL GLC”, product of Kuraray Chemical Co., Ltd.; 30 g), and without a break, was filtered through a 0.2-μm membrane filter. Finally, deionized water (200 g) was added, ethanol was distilled off at 40° C. and 2.7 kPa, and then, the water content was adjusted to obtain a “purified green tea extract”. In the thus-obtained extract, non-polymer catechins were contained at 20.2 wt %. The recovery rate of non-polymer catechins from the tannase-treated solution of Example 16 was 60.5%, and the percentage of gallates in the non-polymer catechin composition was 29.3 wt %. Further, caffeine was 0.73 wt %, and the content of gallic acid was 2.56 wt %. The non-polymer catechins in the solid content of the tea extract amounted to 56.6 wt %.

(63) The tea extracts described in Examples 15 to 19 and Comparative Examples 7 to 10 were subjected to sterilization treatment under the Food Sanitation Act of Japan, were then assessed for flavor/taste and bitterness. The results are shown in Table 8.

(64) After the treatment in each of Examples 15 to 19, the recovery rate of non-polymer catechins was high, the concentration of caffeine had been lowered, and the tea extract so obtained was substantially free of gallic acid and was low in the concentration of caffeine. In Example 20, the produced beverage was good in external appearance and the stability of taste. In Comparative Example 7, a sour taste and coarse taste remained, and in Comparative Example 8, bitterness remained. In Comparative Example 9, the content of caffeine was high, and in Comparative Example 10, a sour taste remained.

(65) TABLE-US-00008 TABLE 8 Example 15 Example 16 Example 17 Example 18 Example 19 Tannase treatment Treated Treated Treated Treated Treated <After tannase treatment/analysis data of extract> Content of non-polymer catechins [wt %] 0.89 0.89 0.73 0.89 0.89 Content of caffeine [wt %] 0.20 0.22 0.16 0.20 0.22 Content of gallic acid [wt %] 0.10 0.12 0.22 0.10 0.12 Percentage of non-polymer catechingallates [wt %] 52.4 30.3 4.28 52.4 30.3 Percent reduction of gallates [wt %] 17.1 22.0 47.7 17.1 22.0 <Analysis data after elution from synthetic adsorbent(desorbing solution)> Use/nonuse of synthetic adsorbent, kind SP70 SP70 SP70 SP207 SP70 pH of alkaline aqueous solution [-] 12.5 12.4 12.5 14.0 12.6 Concentration of ethanol [wt %] 0 0 0 0 0 Content of non-polymer catechins [wt %] 0.24 0.21 0.18 0.63 0.17 Content of caffeine [wt %] 0 0 0 0 0 Content of gallic acid [wt %] 0.001 0.002 0.004 0.001 0.001 Caffeine/non-polymer catechins ratio [-] 0 0 0 0 0 Gallic acid/non-polymer catechins ratio [-] 0.004 0.009 0.022 0.002 0.006 Recovery rate of non-polymer catechins [%] 92.9 90.3 91.3 88.2 78.2 pH adjustment method Ion Ion Ion Ion Ion exchange exchange exchange exchange exchange (amount: ¼) pH after adjustment [-] 3.0 2.7 3.7 4.1 8.6 Proportion of gallates in purified product [wt %] 55.3 32.5 6.0 58.3 35.8 Non-polymer catechins in solid content [wt %] 62.4 64.7 57.6 59.3 43.3 <Assessment of flavor and taste after Bitterness Slight Very slight None Slight Very slight sterilization> Sour taste None None None None None Coarse No abnormal No abnormal No abnormal No abnormal Slight taste taste or taste or taste or taste or coarse smell smell smell smell taste <Assessment of bitterness> Quinine 6.8 5.5 5.0 6.7 5.8 sulfate assessment Loading ratio (amount of solution/volume of [BV] 15 15 15 5 15 resin) Comp. Ex. 7 Comp. Ex. 8 Comp. Ex. 9 Comp. Ex. 10 Tannase treatment Treated Not treated Treated Treated <After tannase treatment/analysis data of extract> Content of non-polymer catechins [wt %] 0.89 0.96 0.89 27.8 Content of caffeine [wt %] 0.20 0.24 0.20 6.74 Content of gallic acid [wt %] 0.10 0.01 0.10 3.58 Percentage of non-polymer catechingallates [wt %] 52.4 69.5 52.4 30.3 Percent reduction of gallates [wt %] 17.1 0 17.1 22.0 <Analysis data after elution from synthetic adsorbent (desorbing solution)> Use/nonuse of synthetic adsorbent, kind Not used SP70 SP70 Not used pH of alkaline aqueous solution [-] — 12.5 — — Concentration of ethanol [wt %] — 0 20 92 Content of non-polymer catechins [wt %] — 0.22 0.50 20.2 Content of caffeine [wt %] — 0 0.10 0.73 Content of gallic acid [wt %] — 0.001 0.008 2.56 Caffeine/non-polymer catechins ratio [-] — 0 0.191 0.036 Gallic acid/non-polymer catechins ratio [-] — 0.005 0.016 0.127 Recovery rate of non-polymer catechins [%] — 93.0 84.4 60.5 pH adjustment method — Ion exchange — — pH after adjustment [-] — 3.5 4.0 3.3 Proportion of gallates in purified product [wt %] 52.4 72.1 45.9 29.3 Non-polymer catechins in solid content [wt %] 32.3 69.2 60.8 56.6 <Assessment of flavor and taste after Bitterness Slight Bitter Slight Slight sterilization> Sour taste Sour None None Sour Coarse Coarse No abnormal No abnormal No abnormal taste taste taste or taste or taste or smell smell smell <Assessment of bitterness> Quinine 8.0 7.8 6.8 6.3 sulfate assessment Loading ratio (amount of solution/volume of [BV] resin) — 15 6 —

Example 20

(66) Using the purified green tea extract of Example 17, the beverage described in Table 9 was prepared for packaging application. Under the Food Sanitation Act of Japan, the beverage was subjected to sterilization treatment and then to hot-pack filling so that a packaged beverage was produced.

(67) After the thus-produced packaged beverage was stored at 37° C. for 30 days, it was assessed. It was good in external appearance and the stability of taste.

(68) TABLE-US-00009 TABLE 9 Added Names of materials amounts (%) Sugar 1.50 Salt 0.33 Sweetener 0.01 VC 0.05 Fruit juice 0.10 Flavor 0.20 Purified green tea 70.83 extract (Example 17) Deionized water Balance Total 100.00

Example 21

(69) A crude catechin preparation (product of Mitsui Norin Co., Ltd., the concentration of non-polymer catechins=32.0 wt %, the percentage of non-polymer non-gallate catechins=47.8 wt %, caffeine=5.88 wt %; 150 g) was dissolved at 25° C. for 30 minutes under stirring in deionized water (4,500 g) to obtain a tea extract (pH5.3). Next, a synthetic adsorbent “SP-207” (product of Mitsubishi Chemical Corporation; 861 mL) packed in a stainless steel column 1 (60 mm inner diameter×360 mm height, volume: 1,017.4 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (3,444 mL), and then at SV=5 (h.sup.−1) with water (8,610 mL). An ion-exchange resin “SK1BH” (product of Mitsubishi Chemical Corporation; 350.6 mL) packed in a stainless steel column 2 (38 mm inner diameter×340 mm height, volume: 385.4 mL) was washed beforehand at SV=5 (h.sup.−1) with 95 (v/v) ethanol (1402.4 mL), and then at SV=5 (h.sup.−1) with water (3,506 mL). Subsequently, the tea extract (3,435 g, 4 volumes relative to the synthetic adsorbent) was loaded at SV=1 (h.sup.−1) on the stainless steel column 1 and the outflow was discarded. The column 1 was then washed at SV=2 (h.sup.−1) with water (861 mL, one volume relative to the synthetic adsorbent). Subsequent to the water-washing, a 0.01 wt % aqueous solution of sodium hydroxide (pH 11.5; 12,900 mL, 15 volumes relative to the synthetic adsorbent) was loaded as an eluent at SV=5 (h.sup.−1) to obtain a fraction. The fraction was continuously loaded on the stainless steel column 2 to conduct deionization, so that a purified tea extract (12,860 g, pH 3.5) was obtained. The non-polymer catechins in the purified tea extract amounted to 31.0% when the adsorbed non-polymer catechins were assumed to be 100.

Example 22

(70) An operation was conducted as in Example 21 except that a 20 wt % aqueous solution of ethanol (860 mL, one volume relative to the synthetic adsorbent) was loaded as an eluent at SV=2 (h.sup.−1) and the fraction was not deionized. The non-polymer catechins in the purified tea extract amounted to 41.0% when the adsorbed non-polymer catechins were assumed to be 100.

Comparative Example 11

(71) An operation was conducted as in Example 21 except that a 0.1 wt % aqueous solution of sodium hydroxide (12,900 mL, 15 volumes relative to the synthetic adsorbent) was loaded as an eluent at SV=5 (h.sup.−1). The non-polymer catechins in the purified tea extract amounted to 92.4% when the adsorbed non-polymer catechins were assumed to be 100.

Comparative Example 12

(72) An operation was conducted as in Example 22 except that a 20 wt % aqueous solution of ethanol (5,170 mL, 6 volumes relative to the synthetic adsorbent) was loaded as an eluent at SV=2 (h.sup.−1). The non-polymer catechins in the purified tea extract amounted to 85.0% when the adsorbed non-polymer catechins were assumed to be 100.

(73) The results of Examples 21 and 22 and Comparative Examples 11 and 12 are shown in Table 10.

(74) TABLE-US-00010 TABLE 10 Raw material (tea extract before Example Example Comp. Ex. Comp. Ex. adsorption) 21 22 11 12 Eluent Basic aq. Aq. soln. Basic aq. Aq. soln. soln. of organic soln. of organic solvent solvent Concentration of basic aqueous solution [wt %] 0.01 — 0.1 — Concentration of organic solvent [wt %] — 20 — 20 Loading ratio of eluent [BV] 15 1 15 6 Recovery rate of non-polymer catechins [%] 31.0 41.0 92.4 85.0 Non-polymer catechins [wt %] 0.91 0.09 1.74 0.24 0.63 Caffeine [wt %] 0.17 0.00 0.00 0.00 0.04 Gallic acid [wt %] 0.006 0.000 0.000 0.001 0.000 Caffeine/non-polymer catechins ratio [-] 0.18 0.00 0.00 0.00 0.06 Gallic acid/non-polymer catechins ratio [-] 0.007 0.000 0.000 0.005 0.000 Percentages of respective components in non-polymer catechins GC [wt %] 6.4 10.2 13.3 5.5 7.0 EGC [wt %] 30.9 47.2 57.3 30.6 35.8 C [wt %] 3.2 5.9 1.8 3.4 2.1 EC [wt %] 7.6 9.4 3.9 7.6 8.2 EGCg [wt %] 38.8 25.1 22.5 39.3 40.9 GCg [wt %] 2.1 1.1 0.7 2.2 1.9 ECg [wt %] 9.9 0.9 0.5 10.2 3.9 Cg [wt %] 1.3 0.1 0.0 1.3 0.2 Percentage of non-gallates in non-polymer [wt %] 48.0 72.7 76.2 47.1 53.2 catechins Percentage of gallocatechins [wt %] 78.1 83.7 93.7 77.5 85.6 Percentage of epicatechins [wt %] 87.1 82.6 84.2 87.6 88.8 Ratio of non-gallates to raw material [-] — 1.51 1.59 0.98 1.11 Ratio of gallocatechins to raw material [-] — 1.07 1.20 0.99 1.10 Ratio of epicatechins to raw material [-] — 0.95 0.97 1.01 1.02 Assessment of flavor and taste Tea flavor Felt Not felt Not felt Not felt Not felt Bitterness 8 6 6 8 8

(75) As evident from Table 10, a purified tea extract having a lowered caffeine content, a high percentage of non-polymer non-gallate catechins, a reduced tea flavor and taste, reduced bitterness and an improved flavor and taste can be obtained by adsorbing a tea extract on a synthetic adsorbent, bringing a washing solution into contact with the synthetic adsorbent, and then bringing an eluent into contact with the synthetic adsorbent to fractionate, as fractionation conditions, from 10 to 60% of non-polymer catechins adsorbed on the synthetic adsorbent. The extract is, therefore, useful not only as a tea-based beverage but also as a non-tea-based beverage.