Black Tea Extract and Preparation Method Therefor

Abstract

A black tea extract, comprising 20-30% parts by weight of theaflavin and 40-50% parts by weight of catechin. The theaflavin and the catechin in the black tea extract can be obtained by conventional high-concentration tea polyphenol extraction in the art, and can also be commercially available theaflavin and catechin in the art.

Claims

1. A black tea extract, wherein, by mass fraction, comprising the following ingredients: 20-30% of theaflavins and 40-50% of catechins.

2. The black tea extract according to claim 1, wherein, the theaflavins are composed of TF1, TF2A, TF2B, and TF3, and the content of TF1, TF2A, TF2B, and TF3 in mass fraction ratio is: TF1:(TF2A+TF2B):TF3=(4.8-7.1):(8.8-11.4):(4.3-5.2).

3. The black tea extract according to claim 1, wherein, the catechins contain ECG, EGCG, EGC, and C, and the content of ECG, EGCG, EGC, and C in mass fraction ratio is: ECG:EGCG:EGC:C=(6.0-12.6):(24.6-29.8):(2.4-5.6):(0.4-0.8).

4. The black tea extract according to claim 1, wherein, the mass fraction of the theaflavins in the black tea extract is 23.1, and the mass fraction of the catechins is 46.5; or the mass fraction of the theaflavins is 25, and the mass fraction of the catechins is 45.

5. A preparation method for a black tea extract, wherein, comprising the following steps: (1) Pulverizing fresh tea leaves; (2) Mixing evenly the tea polyphenols with the fresh tea leaves after pulverizing, the mass ratio of the tea polyphenols to the fresh tea leaves after pulverizing is (10-20):1; (3) Fermenting the evenly mixed raw materials in step (2) at a temperature range of 25-27 C., until the mass fraction of the theaflavins in the raw materials falling within the range of 20-30% to deliver a black tea extract.

6. The preparation method according to claim 5, wherein, the pulverization treatment in step (1) is carried out by pulverizing the fresh tea leaves with a pulverizer and passing through a sieve of 80 mesh.

7. The preparation method according to claim 5, wherein, the fermentation time in step (3) is 6.5 to 7.5 hours; and after the fermentation in step (3), tea polyphenol is further added to adjust the content of each ingredient in the black tea extract.

8. The preparation method according to claim 5, wherein, after the black tea extract is obtained in step (3), the black tea extract is extracted, concentrated, and dried to obtain a black tea extract powder.

9. The preparation method according to claim 8, wherein, the extraction is carried out with water; or, the concentration is the concentration under reduced pressure; or, the drying is spray drying.

10. A black tea extract prepared by the preparation method for a black tea extract according to claim 5.

11. The black tea extract according to claim 2, wherein, the catechins contain ECG, EGCG, EGC, and C, and the content of ECG, EGCG, EGC, and C in mass fraction ratio is: ECG:EGCG:EGC:C=(6.0-12.6):(24.6-29.8):(2.4-5.6):(0.4-0.8).

12. The black tea extract according to claim 2, wherein, the mass fraction of the theaflavins in the black tea extract is 23.1, and the mass fraction of the catechins is 46.5; or the mass fraction of the theaflavins is 25, and the mass fraction of the catechins is 45.

13. The black tea extract according to claim 3, wherein, the mass fraction of the theaflavins in the black tea extract is 23.1, and the mass fraction of the catechins is 46.5; or the mass fraction of the theaflavins is 25, and the mass fraction of the catechins is 45.

14. A black tea extract prepared by the preparation method for a black tea extract according to claim 6.

15. A black tea extract prepared by the preparation method for a black tea extract according to claim 7.

16. A black tea extract prepared by the preparation method for a black tea extract according to claim 8.

17. A black tea extract prepared by the preparation method for a black tea extract according to claim 9.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] The theaflavins 40 and the theaflavins 60 mentioned in the following comparative embodiments were purchased from NASHAI Corporation of the United States.

[0036] The catechins mentioned in the following comparative embodiments were purchased from NASHAI Corporation of the United States.

[0037] In the following embodiments, comparative embodiments and effect embodiments, the content of each monomer of theaflavins was determined by an external standard method, TF1 (Theaflavin), TF2A+TF2B (Mixture of Theaflavin 3-gallate and Theaflavin 3-gallate), TF3 (Theaflavin 3,3-digallate), the three set of monomer standards were purchased from Sigma.

[0038] In the following embodiments, comparative embodiments and effect embodiments, the content of each monomer of catechins was determined by an external standard method, C and EGCG standards were purchased from Sigma, and the remaining monomers were determined as a function of the conversion coefficient to obtain a standard curve.

[0039] In the following embodiments and comparative embodiments, HPLC detection conditions were as following: column: ODS (C18); mobile phase: acetonitrile and 0.1% phosphoric acid solution; column temperature: 35 C.; flow rate: 2 mL/min; detection wavelength: 280 nm; injection amount: 10 L.

Embodiment 1

[0040] Provided in the embodiment were a black tea extract and a preparation method therefor. The black tea extract of the embodiment contained 23.1% of theaflavins, 46.5% of catechins, and 30.4% of other black tea fermenting substances (main ingredients including theabrownins, thearubigins, tannic acid, and gallic acid).

[0041] Wherein, the contents of TF1, TF2A and TF2B, and TF3 in theaflavins were 6.9%, 11.1%, and 5.1%, respectively.

[0042] Wherein, the contents of C, EGC, EGCG and ECG in catechins were 0.6%, 3.9%, 27.2%, and 8.0%, respectively.

[0043] The above percentage was the mass percentage of each ingredient to the black tea extract.

[0044] The black tea extract of the embodiment was obtained by the following method:

[0045] 100 g fresh tea leaves was pulverized with a pulverizer and passed through an 80-mesh sieve; 1000 g of tea polyphenols was charged into a fermentation tank, the fresh tea leaves after pulverization was then added into, uniformly mixed, after fermenting at a temperature of 26 C. for 6.5 hours, the ingredient content was monitored in real time by HPLC every 15 min. When the mass percentage of theaflavins was determined to be 23.1%, the fermentation was terminated, and the black tea extract was obtained when the fermenting time was 7 hours in total. The black tea extract was extracted with ten times the amount of water, and the two extracts were combined, concentrated under reduced pressure, and dried to obtain a black tea extract powder.

Embodiment 2

[0046] Provided in the embodiment were a black tea extract and a preparation method therefor. The black tea extract of the embodiment contained 35.7% of theaflavins and 64.3% of catechins.

[0047] Wherein, the contents of TF1, TF2A and TF2B, and TF3 in theaflavins were 10%, 17.1%, and 8.6%, respectively.

[0048] Wherein, the contents of C, EGC, EGCG and ECG in catechins were 0.8%, 6.5%, 40.7%, 16.3%, respectively.

[0049] The above percentage was the mass percentage of each ingredient to the black tea extract.

[0050] The black tea extract of the embodiment was obtained by the following method:

[0051] 100 g of commercially available theaflavins 40, 276 g of commercially available theaflavins 60 and 200 g of tea polyphenol were mixed, and the content of each ingredient was monitored by HPLC in real time. When the content of theaflavins was 35.7%, the preparation was terminated.

Comparative Embodiment 1

[0052] Provided in the embodiment were a black tea extract and a preparation method therefor. The black tea extract of the embodiment contained 5.8% of theaflavins, 73.2% of catechins, and 21.0% of other black tea fermenting substances (main ingredients including theabrownins, thearubigins, tannic acid, and gallic acid).

[0053] Wherein, the contents of TF1, TF2A and TF2B, and TF3 in theaflavins were 1.6%, 2.9%, and 1.3%, respectively.

[0054] Wherein, the contents of C, EGC, EGCG and ECG in catechins were 1.1%, 6.2%, 43.1%, 12.6%, respectively.

[0055] The above percentage was the mass percentage of each ingredient to the black tea extract.

[0056] The black tea extract of the comparative embodiment was obtained by the following method:

[0057] 100 g of Jiangxi Wuyuan green tea was fermented for 7 hours by simulating black tea production process. The black tea extract was extracted with ten times the amount of water, and the two extracts were combined, concentrated under reduced pressure, and dried, the content of each ingredient was determined by HPLC, wherein the mass percentage of theaflavins was 5.8%.

Comparative Embodiment 2

[0058] Provided in the comparative embodiment were a black tea extract and a preparation method therefor. The black tea extract of the embodiment contains 42.8% of theaflavins, 26.8% of catechins, and 30.4% of other black tea fermenting substances (main ingredients including theabrownins, thearubigins, tannic acid, and gallic acid) (similar to the composition of commercially available theaflavin 40).

[0059] Wherein, the contents of TF1, TF2A and TF2B, and TF3 in theaflavins were 12.9%, 21.1%, and 8.8%, respectively.

[0060] Wherein, the contents of C, EGC, EGCG and ECG in catechins were 0.4%, 2.4%, 15.6%, 4.8%, respectively.

[0061] The above percentage was the mass percentage of each ingredient to the black tea extract.

[0062] The black tea extract of the comparative embodiment was obtained by the following method:

[0063] The black tea extract obtained from Example 1 was used as raw material, and extracted with ethyl acetate and sodium bicarbonate solution by Roberts method to obtain high purity theaflavin. HPLC was used to determine the content of theaflavin in the extract, and then commercially available catechins was added, to adjust mass percentage of theaflavins in the extract to 42.8%.

Comparative Embodiment 3

[0064] Provided in the comparative embodiment were a black tea extract and a preparation method therefor. The black tea extract of the embodiment contains 63.7% of theaflavins, 10.5% of catechins, and 25.8% of other black tea fermenting substances (main ingredients including theabrownins, thearubigins, tannic acid, and gallic acid) (similar to the composition of commercially available theaflavin 60).

[0065] Wherein, the contents of TF1, TF2A and TF2B, and TF3 in theaflavins were 19.4%, 30.7%, and 13.6%, respectively.

[0066] Wherein, the contents of C, EGC, EGCG and ECG in catechins is 0.1%, 0.9%, 6.3%, 1.7%, respectively.

[0067] The above percentage was the mass percentage of each ingredient to the black tea extract.

[0068] The black tea extract of the comparative embodiment was obtained by the following method:

[0069] The black tea extract obtained from Example 1 was used as raw material, and extracted with ethyl acetate and sodium bicarbonate solution by using Roberts method to obtain theaflavins with high purity. The content of theaflavins in the extract was determined by HPLC, and then commercially available catechins was added, to adjust mass percentage of theaflavins therein to be 63.7%.

Effect Example 1

[0070] 42 male C57BL mice, three weeks old, were divided into 7 groups on average, including high fat group (HF), low fat group (LF) and 5 groups of tea extract group (TE1-5), with 6 rats in each group. Each two were housed separately in a metabolic cage. In the first four weeks (Day1-Day30), all mice in the six groups were fed with high-fat diet (45% calories from fat) and ate freely. From the fifth week (Day31-Day52), the fodder of the low fat group was replaced with low fat diet (10% calories from fat), and the fodders of the tea extract groups were mixed with 0.5% of black tea extracts with different contents of theaflavins into the high fat diet, wherein the TE1 group used the black tea extract of embodiment 1; the TE2 group used the black tea extract of embodiment 2; the TE3 group used the black tea extract of comparative embodiment 1; the TE4 group used the black tea extract of comparative embodiment 2; and the TE5 group used the black tea extract of comparative embodiment 3. The animals were kept feeding for 4 weeks, and the body weight, food intake and fecal fat content of each group were recorded. All the feeds were purchased from the Teklad feeds of Envigo, and the contents of the black tea extracts of each tea extract group were shown in Table 1 and Table 2

TABLE-US-00001 TABLE 1 Contents of theaflavins and ingredients therein in tea extracts (%) Theaflavins TF1 TF2A + TF2B TF3 TE1 23.1 6.9 11.1 5.1 TE2 35.7 10 17.1 8.6 TE3 5.8 1.6 2.9 1.3 TE4 42.8 12.9 21.1 8.8 TE5 63.7 19.4 30.7 13.6

TABLE-US-00002 TABLE 2 Contents of catechins and ingredients therein in tea extracts (%) Catechins ECG EGCG EGC C TE1 46.5 8.0 27.2 3.9 0.6 TE2 64.3 16.3 40.7 6.5 0.8 TE3 73.2 12.6 43.1 6.2 1.1 TE4 26.8 4.8 15.6 2.4 0.4 TE5 10.5 1.7 6.3 0.9 0.1

[0071] After the above mice were fed for 52 days, the data records of each group are shown in Table 3.

TABLE-US-00003 TABLE 3 Average daily feed consumption per two mice (g/day) Day 32 Day 36 Day 40 Day 44 Day 48 Day 52 HF 6.1 0.8 6.6 0.6 6.4 0.4 6.2 0.2 6.1 0.2 6.1 0.1 LF 4.9 0.3 5.8 0.4 5.9 0.3 6.2 0.2 5.9 0.2 6.2 0.1 TE1 7.9 0.6 6.5 0.3 6.4 0.4 6.3 0.1 6.1 0.2 6.1 0.1 TE2 7.8 0.5 6.6 0.2 6.3 0.4 6.3 0.1 6.0 0.3 6.1 0.1 TE3 6.5 0.4 6.5 0.4 6.4 0.3 6.2 0.2 6.1 0.1 6.2 0.1 TE4 7.1 0.7 6.4 0.4 6.5 0.3 6.3 0.2 6.1 0.2 6.1 0.1 TE5 2.2 0.1 4.7 0.5 5.3 0.3 5.2 0.1 5.4 0.3 5.2 0.1

[0072] After changing the diet on the 32nd day, the food intake by mice of the TE5 group showed a significant decrease, and the mice in this group showed some signs of restlessness, such as shredding the food, arching back and the like. Two mice in the TE4 group appeared as similar mild situation, while none in the other groups were appeared as similar situation. Probably because the high content of theaflavins stimulated the gastric mucosa of mice, causing discomfort in the stomach. After gradual adaptation, the food intake of mice in group TE5 increased to a certain extent.

[0073] The fat content in the feces of mice was measured, and the data were shown in table 4:

TABLE-US-00004 TABLE 4 Average fat content in feces (%) Day 32 Day 36 Day 40 Day 44 Day 48 Day 52 HF 0.07 0.01 0.06 0.01 0.09 0.01 0.05 0.01 0.06 0.01 0.05 0.01 LF 0.06 0.01 0.04 0.01 0.04 0.01 0.03 0.01 0.04 0.01 0.04 0.01 TE1 0.13 0.03 0.10 0.04 0.12 0.02 0.11 0.03 0.11 0.03 0.13 0.02 TE2 0.13 0.02 0.11 0.04 0.13 0.02 0.11 0.02 0.12 0.02 0.13 0.01 TE3 0.09 0.01 0.07 0.01 0.10 0.01 0.07 0.02 0.08 0.01 0.07 0.01 TE4 0.14 0.03 0.11 0.03 0.12 0.01 0.11 0.01 0.11 0.02 0.13 0.02 TE5 0.16 0.04 0.11 0.02 0.12 0.02 0.09 0.01 0.12 0.01 0.11 0.02

[0074] The results of data analysis showed that the fat contents in feces of the tea extract groups were significantly higher than that of the high fat group and low fat groups. In the tea extract groups, the TE3 group was slightly lower than the other three groups, and there was no statistical difference between the other three groups. It can be seen that theaflavins are not a single factor affecting fecal fat excretion, and there is a certain synergistic relationship between theaflavins and catechins.

[0075] Combined with the data of food intake, the behavior of feeding mice and fecal fat excretion, it can be seen that the proportion of each ingredient in the tea extract provided by the present invention is the best proportion, which not only achieved the best effect, but also greatly reduced the side effects brought by theaflavins.

[0076] It is to be understood that the foregoing description of preferred embodiments is intended to be purely illustrative of the principles of the present invention, rather than exhaustive thereof, and that changes and variations will be apparent to those skilled in the art without departing from the principles and essence of the present invention. Accordingly, the scope of protection of the present invention is limited by the appended claims.