CN112940052A - Preparation method of green tea extract - Google Patents

Preparation method of green tea extract Download PDF

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Publication number
CN112940052A
CN112940052A CN202110282826.1A CN202110282826A CN112940052A CN 112940052 A CN112940052 A CN 112940052A CN 202110282826 A CN202110282826 A CN 202110282826A CN 112940052 A CN112940052 A CN 112940052A
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cooking
tea leaves
filtrate
green tea
residue
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CN202110282826.1A
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Chinese (zh)
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朱仕龙
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Junlian Junquan Tea Co ltd
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Junlian Junquan Tea Co ltd
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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07GCOMPOUNDS OF UNKNOWN CONSTITUTION
    • C07G5/00Alkaloids
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07GCOMPOUNDS OF UNKNOWN CONSTITUTION
    • C07G99/00Subject matter not provided for in other groups of this subclass

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Tea And Coffee (AREA)

Abstract

The invention discloses a preparation method of a green tea extract, which comprises the following steps: s1, pre-purifying fresh tea leaves, cooking the tea leaves in a drawer, and recovering cooking liquor, cooking steam and cooking residues; s2, condensing, refluxing, steaming and boiling steam, filtering by a molecular membrane, and collecting condensed filtrate and condensed residues; s3 adding acetic acid into the cooking liquor to adjust the pH value, standing overnight, performing suction filtration, performing molecular membrane filtration, and collecting the cooking filtrate and the cooking residue; s4, uniformly mixing the cooking filtrate, the cooking residue, the condensation residue and the cooking residue, and rectifying to obtain a rectification liquid and waste; adding cooking filtrate into the S5 waste, returning to S3, and adjusting pH to 4-5 with hydrochloric acid to obtain circulating rectification liquid and circulating waste residue; s6 freeze drying to obtain green tea extract; the invention has the beneficial effects that: through the steps, pure cooking liquor components are obtained, and then the target product with high activity and high purity is obtained through freeze drying.

Description

Preparation method of green tea extract
Technical Field
The invention relates to the field of extraction and purification, in particular to a preparation method of a green tea extract.
Background
The green tea extract is an active ingredient extracted from green tea leaves, and mainly comprises tea polyphenol (catechin), caffeine, aromatic oil, water, minerals, pigments, carbohydrates, proteins, amino acids, vitamins, etc. The prior art of green tea extract mainly distills green tea for extraction and sterilization, but the prior art of extracting green tea mainly distills green tea after directly removing wax, lacks measures such as tea softening and chlorophyll protection, maintains the basic conversion rate of tea extraction at about 85%, and because the adopted cooking process cannot finely distinguish components among all extract components of tea, the various components are mixed to form agglomerates in the cooking and extracting process, purer products such as tea polyphenol, caffeine and the like cannot be obtained, and the change of pH value in the treatment stage is severe, so that the loss of effective components in the tea is large.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a preparation method of a green tea extract, so as to at least achieve the aims of high-efficiency extraction and obtaining of a high-purity target product.
The purpose of the invention is realized by the following technical scheme:
a method for preparing green tea extract comprises the following steps:
s1 selecting fresh tea leaves, pre-purifying and cleaning the tea leaves, steaming the tea leaves in a drawer, recovering cooking liquor and cooking steam, and recovering the cooked residues;
s2, condensing and refluxing the recovered cooking steam to obtain condensate, filtering the obtained condensate by a molecular membrane, and collecting condensed filtrate and condensed residues;
s3, adding acetic acid into the obtained cooking liquor to adjust the pH value to 5-6, standing the cooking liquor overnight, carrying out suction filtration on the cooking liquor after the overnight, filtering by using a molecular membrane, and collecting cooking filtrate and cooking residues;
s4, mixing the cooking filtrate with the cooking residue, the condensation residue and the cooking residue, stirring uniformly, rectifying to obtain a rectification liquid and recovering waste;
s5, adding the waste into the cooking filtrate again, returning to S3, adjusting the pH to 4-5 with hydrochloric acid, and performing circular treatment to obtain circular rectification liquid and circular waste residues;
s6 freeze drying the circulating rectification liquid, the condensed filtrate and the rectification liquid to obtain the green tea extract.
Preferably, for the purpose of further realizing efficient extraction, the pre-purification comprises the following steps:
s11, cleaning the tea leaves with clear water, and soaking the tea leaves in alkaline water for 2 hours to obtain alkalized tea leaves;
s12, putting the obtained alkalized tea leaves into a cleaning pool, and cleaning to obtain clean tea leaves;
s13, soaking the clean tea in acid liquor for 15min to obtain acidified tea;
s14, putting the acidified tea leaves into a cleaning pool, and cleaning to obtain clean tea leaves; the alkaline water adopts sodium bicarbonate solution with mass concentration ratio: sodium carbonate solution =3: 2; the acid liquor adopts the mass concentration ratio of acetic acid: hydrochloric acid =5: 2;
after alkaline washing and soaking, wax of the tea leaves is removed through acid washing, and meanwhile, the damage of strong acid and strong alkali to effective components of the tea leaves is avoided aiming at the alkaline washing and acid washing in the tea leaves, and impurities generated in the alkaline washing or acid washing stage are washed through a washing tank, so that the extraction efficiency of the effective components in the tea leaves is improved.
Preferably, in order to further improve the purity of the target product, the circulating rectification liquid, the condensed filtrate and the rectification liquid are mixed according to a mass ratio of 5:3: 2; the treatment liquids obtained in the steps are mixed according to the dissolution characteristics of different process products and the mass ratio of 5:3:2, so that the treatment liquids with different molecular weights or concentrations can be uniformly mixed, and the extraction purity of different target products is further higher.
Preferably, in order to further achieve the purpose of improving the purity of the target product, the molecular membrane is 3000-8000 Da; by adopting the molecular membrane with small molecular weight, impurities meeting conditions are filtered, and filtered waste can be reused, so that extracts with different molecular weights are fully extracted, and then substances with different molecular weights are distinguished through the molecular membrane, so that the purity of a target product is improved.
The invention has the beneficial effects that:
1. the method comprises the steps of adopting pre-purified tea leaves, adopting a traditional cooking process, finally carrying out different treatments on condensate and cooking liquor, acidifying with acetic acid and standing overnight according to the characteristics of macromolecular impurities such as protein, pigment and carbohydrate in the cooking liquor to remove part of the macromolecular impurities, circularly removing the impurities in the cooking liquor for multiple times through a circular treatment process to obtain pure cooking liquor components, and freeze-drying to obtain a target product with high activity and high purity.
2. After alkaline washing and soaking, wax of the tea leaves is removed through acid washing, and meanwhile, the damage of strong acid and strong alkali to effective components of the tea leaves is avoided aiming at the alkaline washing and acid washing in the tea leaves, and impurities generated in the alkaline washing or acid washing stage are washed through a washing tank, so that the extraction efficiency of the effective components in the tea leaves is improved.
3. The treatment liquids obtained in the steps are mixed according to the dissolution characteristics of different process products and the mass ratio of 5:3:2, so that the treatment liquids with different molecular weights or concentrations can be uniformly mixed, and the extraction purity of different target products is further higher.
4. By adopting the molecular membrane with small molecular weight, impurities meeting conditions are filtered, and filtered waste can be reused, so that extracts with different molecular weights are fully extracted, and then substances with different molecular weights are distinguished through the molecular membrane, so that the purity of a target product is improved.
Detailed Description
The technical solutions of the present invention are described in further detail below, but the scope of the present invention is not limited to the following.
Example 1
A method for preparing green tea extract comprises the following steps:
s1 selecting fresh tea leaves, pre-purifying and cleaning the tea leaves, steaming the tea leaves in a drawer, recovering cooking liquor and cooking steam, and recovering the cooked residues;
s2, condensing and refluxing the recovered cooking steam to obtain condensate, filtering the obtained condensate by a molecular membrane, and collecting condensed filtrate and condensed residues;
s3, adding acetic acid into the obtained cooking liquor to adjust the pH value to 6, standing the cooking liquor overnight, carrying out suction filtration on the cooking liquor after the overnight, filtering by using a molecular membrane, and collecting cooking filtrate and cooking residues;
s4, mixing the cooking filtrate with the cooking residue, the condensation residue and the cooking residue, stirring uniformly, rectifying to obtain a rectification liquid and recovering waste;
s5, adding the waste into the cooking filtrate again, returning to S3, adjusting the pH value to 5 with hydrochloric acid, and performing circular treatment to obtain circular rectification liquid and circular waste residues;
s6 freeze drying the circulating rectification liquid, the condensed filtrate and the rectification liquid to obtain the green tea extract.
Preferably, for the purpose of further realizing efficient extraction, the pre-purification comprises the following steps:
s11, cleaning the tea leaves with clear water, and soaking the tea leaves in alkaline water for 2 hours to obtain alkalized tea leaves;
s12, putting the obtained alkalized tea leaves into a cleaning pool, and cleaning to obtain clean tea leaves;
s13, soaking the clean tea in acid liquor for 15min to obtain acidified tea;
s14, putting the acidified tea leaves into a cleaning pool, and cleaning to obtain clean tea leaves; the alkaline water adopts sodium bicarbonate solution with mass concentration ratio: sodium carbonate solution =3: 2; the acid liquor adopts the mass concentration ratio of acetic acid: hydrochloric acid =5: 2;
after alkaline washing and soaking, wax of the tea leaves is removed through acid washing, and meanwhile, the damage of strong acid and strong alkali to effective components of the tea leaves is avoided aiming at the alkaline washing and acid washing in the tea leaves, and impurities generated in the alkaline washing or acid washing stage are washed through a washing tank, so that the extraction efficiency of the effective components in the tea leaves is improved.
In order to further improve the purity of the target product, the circulating rectification liquid, the condensed filtrate and the rectification liquid are mixed according to the mass ratio of 5:3: 2; the treatment liquids obtained in the steps are mixed according to the dissolution characteristics of different process products and the mass ratio of 5:3:2, so that the treatment liquids with different molecular weights or concentrations can be uniformly mixed, and the extraction purity of different target products is further higher.
In order to further realize the purpose of improving the purity of a target product, the molecular membrane adopts 5000 Da; by adopting the molecular membrane with small molecular weight, impurities meeting conditions are filtered, and filtered waste can be reused, so that extracts with different molecular weights are fully extracted, and then substances with different molecular weights are distinguished through the molecular membrane, so that the purity of a target product is improved.
Example 2
Adjusting the pH of the acetic acid to 6 in step S3; the pH of the solution was adjusted to 4 by hydrochloric acid in S5, 3000Da was used for the molecular membrane, and the procedure was as in example 1.
Example 3
Adjusting the pH of the acetic acid to 5 in step S3; the pH of the solution was adjusted to 5 by hydrochloric acid in S5, the molecular membrane was 4000Da, and the procedure was the same as in example 1.
Example 4
Adjusting the pH of the acetic acid to 5 in step S3; the pH of the solution was adjusted to 5 with hydrochloric acid in S5, the molecular membrane was 5000Da, and the procedure was the same as in example 1.
Example 5
Adjusting the pH of the acetic acid to 5 in step S3; the pH of the solution was adjusted to 5 with hydrochloric acid in S5, the molecular membrane was 6000Da, and the procedure was the same as in example 1.
Example 6
Adjusting the pH of the acetic acid to 5 in step S3; the pH of the solution was adjusted to 5 by hydrochloric acid in S5, 7000Da was used for the molecular membrane, and the procedure was the same as in example 1.
Example 7
Adjusting the pH of the acetic acid to 5 in step S3; the pH of the solution is adjusted to 5 by hydrochloric acid in S5, 8000Da is used for molecular membrane, and the rest steps are the same as those in example 1.
Comparative example 1
The preliminary purification was carried out with an alkaline wash, and the rest of the procedure was as in example 1.
Comparative example 2
The preliminary purification was carried out by acid washing, and the rest of the procedure was the same as in example 1.
Comparative example 3
The procedure of example 1 was followed except that the molecular membrane filtration was not carried out and only the filter paper was used.
The recovery rate and the product purity of the green tea extract of each example and each comparative example are counted, wherein the product purity is mainly tea polyphenol, the specific detection method is the same as the standard GB 8313-87, and the recovery rate of the green tea extract is as follows:
the recovery rate = green tea extract/(fresh tea leaves weight-recycling waste residue),
the above data were counted to obtain table 1.
TABLE 1 Table of recovery and product purity of green tea extraction in each example and comparative example
Figure DEST_PATH_IMAGE002
As can be seen from table 1, when the above-described steps are employed, the pH of acetic acid in step S3 is adjusted to 6; and the pH value of hydrochloric acid in S5 is adjusted to 5, a molecular membrane adopts 5000Da, the recovery rate of the obtained green tea extract is 96%, and the purity is 89%, so that the superiority of the application is proved.
The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. A preparation method of a green tea extract is characterized by comprising the following steps: the method comprises the following steps:
s1 selecting fresh tea leaves, pre-purifying and cleaning the tea leaves, steaming the tea leaves in a drawer, recovering cooking liquor and cooking steam, and recovering the cooked residues;
s2, condensing and refluxing the recovered cooking steam to obtain condensate, filtering the obtained condensate by a molecular membrane, and collecting condensed filtrate and condensed residues;
s3, adding acetic acid into the obtained cooking liquor to adjust the pH value to 5-6, standing the cooking liquor overnight, carrying out suction filtration on the cooking liquor after the overnight, filtering by using a molecular membrane, and collecting cooking filtrate and cooking residues;
s4, mixing the cooking filtrate with the cooking residue, the condensation residue and the cooking residue, stirring uniformly, rectifying to obtain a rectification liquid and recovering waste;
s5, adding the waste into the cooking filtrate again, returning to S3, adjusting the pH to 4-5 with hydrochloric acid, and performing circular treatment to obtain circular rectification liquid and circular waste residues;
s6 freeze drying the circulating rectification liquid, the condensed filtrate and the rectification liquid to obtain the green tea extract.
2. The method for preparing a green tea extract according to claim 1, wherein: the pre-purification comprises the following steps:
s11, cleaning the tea leaves with clear water, and soaking the tea leaves in alkaline water for 2 hours to obtain alkalized tea leaves;
s12, putting the obtained alkalized tea leaves into a cleaning pool, and cleaning to obtain clean tea leaves;
s13, soaking the clean tea in acid liquor for 15min to obtain acidified tea;
s14, putting the acidified tea leaves into a cleaning pool to clean, and obtaining clean tea leaves.
3. The method for preparing a green tea extract according to claim 2, wherein: the alkaline water adopts sodium bicarbonate solution with mass concentration ratio: sodium carbonate solution =3: 2.
4. The method for preparing a green tea extract according to claim 2, wherein: the acid liquor adopts the mass concentration ratio of acetic acid: hydrochloric acid =5: 2.
5. The method for preparing a green tea extract according to claim 1, wherein: the circulating rectification liquid, the condensed filtrate and the rectification liquid are mixed according to the mass ratio of 5:3: 2.
6. the method for preparing a green tea extract according to any one of claims 1 to 5, wherein: the molecular membrane is 3000-8000 Da.
CN202110282826.1A 2021-03-16 2021-03-16 Preparation method of green tea extract Pending CN112940052A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101715853A (en) * 2009-12-22 2010-06-02 云南龙润茶业集团有限公司 Instant black tea powder and preparation method and application thereof
CN102972557A (en) * 2012-11-25 2013-03-20 北京化工大学 Method for producing instant tea powder by using steam explosion technology to treat tea raw materials
CN103859098A (en) * 2014-04-04 2014-06-18 绍兴御茶村茶业有限公司 Preparation method for green tea type extract
CN106720701A (en) * 2016-12-14 2017-05-31 雅安市雨城区晏场鹿井茶厂 A kind of preparation method and application of instant lotus leaf tea powder
CN107927282A (en) * 2017-12-08 2018-04-20 贵州绿视野绿色开发有限公司 A kind of processing method of green tea extract
CN110178922A (en) * 2019-07-08 2019-08-30 四川大学 A kind of ultramicro grinding green tea powder, preparation method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101715853A (en) * 2009-12-22 2010-06-02 云南龙润茶业集团有限公司 Instant black tea powder and preparation method and application thereof
CN102972557A (en) * 2012-11-25 2013-03-20 北京化工大学 Method for producing instant tea powder by using steam explosion technology to treat tea raw materials
CN103859098A (en) * 2014-04-04 2014-06-18 绍兴御茶村茶业有限公司 Preparation method for green tea type extract
CN106720701A (en) * 2016-12-14 2017-05-31 雅安市雨城区晏场鹿井茶厂 A kind of preparation method and application of instant lotus leaf tea powder
CN107927282A (en) * 2017-12-08 2018-04-20 贵州绿视野绿色开发有限公司 A kind of processing method of green tea extract
CN110178922A (en) * 2019-07-08 2019-08-30 四川大学 A kind of ultramicro grinding green tea powder, preparation method thereof

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Application publication date: 20210611