High-umami tea extract liquid based on multi-mode coupling extraction and preparation method of high-umami tea extract liquid

Abstract

The invention discloses a preparation method of a high-umami tea extract based on multi-mode coupling extraction, which comprises the following steps: an auxiliary wall breaking process: adding enzyme into tea leaves, and carrying out enzymolysis for 30-60 minutes at the pH value of 4.5-5.5 and the temperature of 40-50 DEG C; a gradient extraction process: extracting the tea leaves subjected to enzymolysis by adopting an ice-water mixture at 0-5 DEG C for 3-10 minutes according to a tea-water ratio of (1: 5)-(1: 10) (w / v), so as to obtain a first extract and first tea residues; transferring the first tea residues subjected to low-temperature extraction into water with the temperature of 40-60 DEG C according to the tea-water ratio of (1: 30)-(1: 50) (w / v), and extracting for 20-60 minutes to obtain second extraction liquid and second tea residues; the pH value is adjusted to 3.0-4.0, the second tea residues are extracted for 5-10 min at the temperature of 40-60 DEG C, the tea-water ratio is 1: 10-1: 30 (w / v), and third extraction liquid is obtained; and regulating and controlling components: mixing the first leaching solution, the second leaching solution and the third leaching solution, and filtering through an ultrafiltration membrane to obtain the high-umami leaching solution. The prepared tea extract liquid is coordinated in flavor, prominent in delicate flavor and fresh and mellow in taste, and the problem that fresh keeping and efficiency improving cannot be achieved at the same time in the tea leaf processing process is solved.

Description

Technical Field

[0001] This invention belongs to the field of deep processing technology of tea, specifically relating to a method for preparing a high-umami tea extract based on multimodal coupling extraction. Background Technology

[0002] The flavor compounds that dissolve in water after brewing or extraction mainly include tea polyphenols, amino acids, caffeine, soluble sugars, and organic acids. The taste of tea soup is related to the composition and concentration of water-soluble flavor compounds, and is also affected by the interactions between these compounds. Umami, as one of the important indicators for evaluating the taste of tea, is often described as "fresh and refreshing" or "fresh and mellow." "Fresh and refreshing" is a fresh, pleasant, and pleasant feeling produced in the mouth by the harmonious proportion of flavor compounds in the tea soup. It is not only related to the concentration of umami compounds, but also closely related to the phenol-to-amino acid ratio in the tea soup (Xu Mao, Liu Ling, Tong Huarong. Umami and Tea Umami Research [J]. Tea, 2010, 036(002):84-86).

[0003] Traditional tea extract processing often suffers from problems such as loss of heat-sensitive components, low extraction efficiency, and flavor imbalance. Current research on tea flavor primarily focuses on bitterness and sweetness, with a severe lack of research on the umami flavor of tea (Yu Yashu, Feng Xiaoxiao, Liu Yuan. Research progress on the umami perception mechanism of tea [C] / / Abstracts of the 21st Annual Meeting of the Chinese Institute of Food Science and Technology. 2024.). Currently, there are no reports on methods for preparing high-umami tea extracts, lacking a method to reduce the loss of heat-sensitive umami substances and improve the extraction rate of umami substances, as well as a tea extract with harmonious flavor and prominent umami. Therefore, to achieve the goals of "preservation" and "efficiency improvement," a method for preparing high-umami tea extracts has been developed, suitable for the production of high-end tea beverages and flavoring bases. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a high-umami tea extract based on multimodal coupling extraction, wherein the prepared tea extract has a harmonious flavor and prominent umami taste.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: (1) Assisted cell wall breaking process Add enzymes to tea leaves and hydrolyze them at pH 4.5-5.5 and 40-50℃ for 30-60 minutes. (2) Gradient extraction process First stage: The enzymatically hydrolyzed tea leaves are extracted using a mixture of ice water at 0-5℃ for 3-10 minutes at a tea-to-water ratio of 1:5-1:10 (w / v) to obtain the first extract and the first tea residue. Second stage: Transfer the tea residue after the first stage low-temperature extraction to water at 40-60℃, with a tea-to-water ratio of 1:30-1:50 (w / v), and extract for 20-60 min to obtain the second extract and the second tea residue. Third stage: Adjust the pH to 3.0-4.0, and extract the second tea residue at 40-60℃ for 5-10 minutes with a tea-to-water ratio of 1:10-1:30 (w / v) to obtain the third extract; (3) Component regulation The first, second, and third extracts are mixed and filtered through an ultrafiltration membrane to obtain a high-umami extract.

[0006] Preferably, in step (1), the tea leaves are selected from tea tree varieties with an amino acid content of ≥2%, and one bud and two leaves or tender leaves are picked and dried at low temperature for preservation.

[0007] The tea leaves selected are Baiye No. 1, Zhonghuang No. 3, or Longjing No. 43.

[0008] Preferably, the enzymes in step (1) are cellulase and protease.

[0009] The appropriate amount of enzyme added is particularly important. Preferably, in step (1), the amount of cellulase and protease added is 0.1-0.5 u / mL and 500-1000 u / mL, respectively, which is beneficial to the flavor enhancement of the tea extract.

[0010] Preferably, in step (3), the volume ratio of the first extract, the second extract, and the third extract is 10-15:55-70:20-30.

[0011] Preferably, a 10-20 kDa ultrafiltration membrane is used in step (3). This invention uses membrane separation technology to retain large molecular bitter substances and collect an extract rich in small molecular umami substances.

[0012] The present invention also provides a high-umami tea extract obtained by the above preparation method.

[0013] This invention also provides the application of the above-mentioned high-umami tea extract in the production of high-end tea beverages or flavoring bases.

[0014] Compared with the prior art, the present invention has the following advantages: 1. This invention can improve cell disruption rate and increase the extraction rate of umami substances through compound enzymatic hydrolysis technology; 2. This invention, through a gradient extraction process combined with pH control, can maximize the retention of heat-sensitive umami substances; 3. The tea extract obtained by this invention has a fresh and mellow taste; 4. This invention solves the problem of the trade-off between "preservation" and "efficiency improvement" in tea processing through temperature gradient design and precise component control, and is suitable for the production of high-end tea beverages and flavoring bases; 5. This invention is entirely free of organic solvents, making it green and safe. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the embodiments. The following embodiments do not constitute a limitation of the present invention, and certain changes and adjustments made by those skilled in the art within the scope of the claims should also be considered to fall within the scope of the present invention.

[0016] Example 1 (1) Assisted cell wall breaking process A specific tea variety (Baiye No. 1) with an amino acid content ≥2% was selected, and one bud and two leaves or tender leaves were picked and stored at low temperature. Cellulase (0.1 u / mL) and protease (500 u / mL) were added to the tea leaves, and enzymatic hydrolysis was carried out at pH 5 and 40℃ for 60 min. (2) Gradient extraction process First stage: Tea leaves were extracted using a mixture of ice water at 0-5℃ for 3 minutes at a tea-to-water ratio of 1:5 (w / v) to obtain the first extract and the first tea residue; Second stage: Transfer the first tea residue after low-temperature extraction to 40℃ water, with a tea-to-water ratio of 1:30 (w / v), and extract for 60 minutes to obtain the second extract and the second tea residue. Third stage: Adjust the pH to 3.0, extract the second tea residue at 40℃ for 10 min, with a tea-to-water ratio of 1:10 (w / v), to obtain the third extract; (3) Component regulation technology The three extracts were mixed in a volume ratio of 10:70:20. A 10 kDa ultrafiltration membrane was used to remove large-molecule bitter substances and collect the extract rich in small-molecule umami substances.

[0017] Example 2 (1) Assisted cell wall breaking process A specific tea variety (Zhonghuang No. 3) with an amino acid content ≥2% was selected, and one bud and two leaves or tender leaves were picked and stored at low temperature. Cellulase (0.3 u / mL) and protease (800 u / mL) were added to the tea leaves, and enzymatic hydrolysis was carried out at pH 5 and 40℃ for 50 min. (2) Gradient extraction process First stage: Tea leaves were extracted using a mixture of 0-5℃ ice water for 5 minutes at a tea-to-water ratio of 1:5 (w / v) to obtain the first extract and the first tea residue; Second stage: Transfer the first tea residue after low-temperature extraction to 50℃ water, with a tea-to-water ratio of 1:40 (w / v), and extract for 40 minutes to obtain the second extract and the second tea residue. Third stage: Adjust the pH to 4.0, extract the second tea residue at 50℃ for 10 min, with a tea-to-water ratio of 1:20 (w / v), to obtain the third extract; (3) Component regulation technology The three extracts were mixed in a volume ratio of 15:60:25. A 20 kDa ultrafiltration membrane was used to remove large-molecule bitter substances and collect the extract rich in small-molecule umami substances.

[0018] Example 3 (1) Assisted cell wall breaking process A specific tea variety (Longjing No. 43) with an amino acid content ≥2% was selected, and one bud and two leaves or tender leaves were picked and stored at low temperature. Cellulase (0.5 u / mL) and protease (1000 u / mL) were added to the tea leaves, and enzymatic hydrolysis was carried out at pH 5 and 50℃ for 30 min. (2) Gradient extraction process First stage: Tea leaves were extracted using a mixture of ice water at 0-5℃ for 10 minutes at a tea-to-water ratio of 1:10 (w / v) to obtain the first extract and the first tea residue. Second stage: Transfer the first tea residue after low-temperature extraction to 60℃ water, with a tea-to-water ratio of 1:50 (w / v), and extract for 20 minutes to obtain the second extract and the second tea residue. Third stage: Adjust the pH to 4.0, extract the second tea residue at 60℃ for 5 minutes, with a tea-to-water ratio of 1:30 (w / v), to obtain the third extract.

[0019] (3) Component regulation technology The three extracts were mixed in a volume ratio of 15:55:30. A 20 kDa ultrafiltration membrane was used to remove large-molecule bitter substances and collect the extract rich in small-molecule umami substances.

[0020] Comparative Example Comparative Example 1: The extract was prepared using the method of Example 1, except that the auxiliary cell wall breaking process was not used, and the tea leaves were directly extracted.

[0021] Comparative Example 2: The extract was prepared using the method of Example 2, except that the gradient extraction process was not used, and the tea was directly extracted using the second-stage extraction conditions.

[0022] Comparative Example 3: The extract was prepared using the method of Example 3, except that membrane separation technology was not used and the extract was directly mixed.

[0023] Comparative Example 4: The extract was prepared using the method of Example 1, except that the pH of the third stage was 7.

[0024] Comparative Example 5: The extract was prepared using the method of Example 1, except that the enzyme in step (1) was tanninase.

[0025] Comparative Example 6: The extract was prepared using the method of Example 1, except that the amount of cellulase and protease added in step (1) was 1 u / mL and 100 u / mL, respectively.

[0026] Comparative Example 7: The extract was prepared using the method of Example 1, except that a 30 kDa ultrafiltration membrane was used in step (3).

[0027] Comparative Example 8: The extract was prepared using the method of Example 1, except that a 5 kDa ultrafiltration membrane was used in step (3).

[0028] Comparative Example 9: The extract was prepared using the method of Example 1, except that the volume ratio of the first extract, the second extract and the third extract in step (3) was 5:70:25.

[0029] Comparative Example 10: The extract was prepared using the method of Example 1, except that the volume ratio of the first extract, the second extract and the third extract in step (3) was 15:45:40.

[0030] Comparative Example 11: The extract was prepared using the method of Example 1, except that the volume ratio of the first extract, the second extract and the third extract in step (3) was 15:75:10.

[0031] Quality Analysis The umami flavor of the tea extract of this invention was analyzed by electronic tongue and sensory evaluation. The sensory evaluation was scored out of 10 points, and the evaluation results are shown in Table 1.

[0032] Table 1. Electronic tongue analysis and sensory evaluation of tea extracts prepared in the examples and comparative examples. Therefore, compared with Comparative Examples 1-3, the tea extracts prepared in Examples 1-3 have higher umami scores; compared with Comparative Example 1, Example 1 improved the umami value of the tea extract through an assisted cell wall disruption process; compared with Comparative Example 2, Example 2 improved the umami value of the tea extract through a gradient extraction process; compared with Comparative Example 3, Example 3 improved the umami value of the tea extract through membrane separation technology; compared with Comparative Example 4, this invention can maximize the retention of heat-sensitive umami substances by controlling the pH adjustment in the third stage; compared with Comparative Examples 5-6, this invention can improve the cell disruption rate and increase the extraction rate of umami substances through a composite enzymatic hydrolysis technology with specific components; compared with Comparative Examples 7-8, this invention improves the umami value of the tea extract through membrane separation of specific sizes; compared with Comparative Examples 9-11, this invention solves the problem of the incompatibility between "preservation" and "efficiency improvement" in tea processing through precise component control.

Claims

1. A method for preparing a high-umami tea extract based on multimodal coupled extraction, characterized in that, The preparation method includes the following steps: (1) Assisted cell wall breaking process Add enzymes to tea leaves and hydrolyze them at pH 4.5-5.5 and 40-50℃ for 30-60 minutes. (2) Gradient extraction process First stage: The enzymatically hydrolyzed tea leaves are extracted using a mixture of ice water at 0-5℃ for 3-10 minutes at a tea-to-water ratio of 1:5-1:10 (w / v) to obtain the first extract and the first tea residue. Second stage: Transfer the first tea residue after the first stage of low-temperature extraction to water at 40-60℃, with a tea-to-water ratio of 1:30-1:50 (w / v), and extract for 20-60 min to obtain the second extract and the second tea residue. Third stage: Adjust the pH to 3.0-4.0, extract the second tea residue at 40-60℃ for 5-10 minutes, with a tea-to-water ratio of 1:10-1:30 (w / v), to obtain the third extract; (3) Component regulation The first, second, and third extracts are mixed and filtered through an ultrafiltration membrane to obtain a high-umami extract.

2. The method for preparing the high-umami tea extract as described in claim 1, characterized in that, In step (1), the tea leaves are selected from tea tree varieties with an amino acid content of ≥2%, and one bud and two leaves or tender leaves are picked and stored at low temperature.

3. The method for preparing the high-umami tea extract as described in claim 2, characterized in that, The tea leaves selected are Baiye No. 1, Zhonghuang No. 3, or Longjing No.

43.

4. The method for preparing the high-umami tea extract as described in claim 1, characterized in that, The enzymes in step (1) are cellulase and protease.

5. The method for preparing the high-umami tea extract as described in claim 4, characterized in that, In step (1), the amount of cellulase and protease added is 0.1-0.5 u / mL and 500-1000 u / mL, respectively.

6. The method for preparing the high-umami tea extract as described in claim 1, characterized in that, In step (3), the volume ratio of the first extract, the second extract, and the third extract is 10-15:55-70:20-30.

7. The method for preparing the high-umami tea extract as described in claim 1, characterized in that, In step (3), a 10-20 kDa ultrafiltration membrane is selected.

8. A high-flavor tea extract obtained by any one of the preparation methods described in claims 1-7.

9. The application of the high-umami tea extract of claim 8 in the production of high-end tea beverages or flavoring bases.

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