Functional group content measuring method in theabrownin of Pu'er tea

A method of determination, the technology of theabrownin, applied in the direction of material electrochemical variables, etc.

Inactive Publication Date: 2010-06-02
KUNMING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The determination method of the content of functional groups (total acidic groups, carboxyl grou...

Method used

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  • Functional group content measuring method in theabrownin of Pu'er tea
  • Functional group content measuring method in theabrownin of Pu'er tea
  • Functional group content measuring method in theabrownin of Pu'er tea

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Example 1: Precision experiment The content of total acidic groups and carboxyl groups in theabrownin was determined according to the measurement method described above, and each sample in 9 samples was measured in triplicate in parallel, and the average result was taken. The data are shown in Table 1. The results showed that the precision of the determination methods of total acidic group and carboxyl group content was good.

[0032] Table 1 Precision of determination of total acidic groups and carboxyl groups

[0033]

Embodiment 2

[0034] Embodiment 2: recovery rate experiment

[0035] The theabrownin mixture lacks a standard sample with a single component, so salicylic acid with both phenolic and carboxyl groups was chosen as the model, but its molecular weight is much smaller than that of theabrownin, and barium salicylate is slightly soluble in water. As a result, the recovery rate of the total acidic base determination experiment is relatively small, between 94.42% and 97.01%. The data are shown in Table 2 and Table 3. As the molecular weight of organic matter increases and the number of phenolic hydroxyl groups and carboxyl groups increases, the solubility of barium salts and calcium salts formed will become smaller and smaller until they become insoluble. However, the results are reliable for evaluating theabrownin, which has a very complex composition.

[0036] Table 2 Determination results of total acidic group recovery after sample addition

[0037]

[0038] Table 3 Carboxyl group sample re...

Embodiment 3

[0040] Example 3: Sample Analysis

[0041]Precipitate theabrownin successively with 30%, 40%, 50%, 60%, 70%, 80% ethanol to obtain components TB1, TB2, TB3, TB4, TB5, TB6, and determine theabrownin samples according to the law (TB) And the content of acidic functional group in each component, the results are listed in Table 4. It can be seen from the table that the contents of the acidic functional groups in the components of theabrownin show large changes and differences after fractionation by organic solvents. The relationship between the content of acidic functional groups of theabrownin and its pharmacological activity will be the focus of future research.

[0042] Table 4 Determination results of functional group content of samples

[0043]

[0044] Determination method verification

[0045] 2.1 Titration curve of theabrownin

[0046] The pH values ​​of the theabrownin solutions with mass fractions of 0.1%, 1%, and 5% were 6.32, 6.38, and 6.17, respectively, and th...

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Abstract

The invention relates to a functional group content measuring method in theabrownin (TB) of Pu'er tea, comprising the measurement of total acidic group: a sample is dissolved by NaOH standard solution, and then BaCl2 is used for precipitating theabrownin, after the precipitation is filtered, superfluous NaOH in filtrate is titrated with HCL standard solution; the measurement of carboxyl group: the sample is dissolved by NaOH standard solution, and then HCL standard solution with equal amount of the NaOH standard solution is added for neutralization, so as to separate out the theabrownin, and then the theabrownin is reacted with Ca(CH3COO)2 to generate TB-Ca which is insoluble in water and acetic acid, and the dissociated acetic acid amount is the carboxyl group content in TB. The generated acetic acid is titrated with NaOH standard solution, and the phenolic hydroxyl content is obtained by subtraction. The analytical method has simple, accurate operation and good repetitiveness, the repetitivenessis good and the result precision is high, the functional groups in the theabrownin (TB) of Pu'er tea can be measured simply, rapidly and accurately, so as to lay the foundation for the pharmacological action research of the Pu'er tea and deep development and provide reference for the analysis of the functional groups of complex compounds with similar chemical structures with the theabrownin (TB) of Pu'er tea.

Description

technical field [0001] The invention relates to a method for measuring the content of functional groups in theabrownin of Pu'er tea, that is, the determination of the content of functional groups (total acidic groups, carboxyl groups, and phenolic hydroxyl groups) in theabrownin. Background technique [0002] Theabrownin (TB) is a kind of brown pigment in tea which is soluble in water and insoluble in ethyl acetate and n-butanol. 10% to 20% of the quality of dry tea, and less in black tea and green tea. In the past half a century, comprehensive and in-depth researches have been carried out on theaflavins and thearubigins in green tea and black tea at home and abroad, and their chemical composition and formation mechanism have been basically ascertained, but the extraction of theaflavins and thearubigins The research on the remaining non-dialyzable high molecular weight phenolic polymer in Suhou tea soup has been blank. According to the formation mechanism of tea polyphenol...

Claims

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Application Information

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IPC IPC(8): G01N27/42
Inventor 张惠芬秦谊龚加顺李宝才
Owner KUNMING UNIV OF SCI & TECH
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