Method for rapidly detecting interference resistance of sucrose externally doped in tea leaves

A technology for sucrose and tea, applied in the field of anti-interference rapid detection of exogenous addition of sucrose in tea, can solve the problems of interference color judgment and absorbance measurement, sucrose components cannot develop normally, flocculent turbidity, etc. The effect of low chemical level requirements and simple instruments

Active Publication Date: 2018-01-16
TEA RES INST CHINESE ACAD OF AGRI SCI
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Problems solved by technology

[0003] However, in practical application, we found that this method is sensitive and reliable for the detection of sucrose in tea samples such as black tea with a high degree of fermentation, but there are more serious problems in the color development and detection process of green tea (especially summer and autumn green tea). Interference phenomenon: On the one hand, under the conditions of the strongly acidic reaction solution (1:1 hydrochloric acid solution), fructose (produced by hydrolysis of sucrose) and The sample matrix itself will spontaneously undergo a weak color reaction, showing a certain light red color, and easily forming flocculent turbidity, which interferes with color judgment and absorbance measurement; contrary to this phenomenon, in the detection test tube containing the color reagent In this method, some components in the sample matrix interfere with the reaction between resorcinol and fructose, and instead make the sucrose component unable to develop color normally, resulting in false negative test results

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  • Method for rapidly detecting interference resistance of sucrose externally doped in tea leaves
  • Method for rapidly detecting interference resistance of sucrose externally doped in tea leaves
  • Method for rapidly detecting interference resistance of sucrose externally doped in tea leaves

Examples

Experimental program
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Effect test

Embodiment 1

[0038] Comparison experiment of treatment effect of different adsorbents

[0039] 1) Weigh 0.10 g of resorcinol and dissolve it in 100 mL of concentrated hydrochloric acid, mix it with 100 mL of deionized water, and make a color reagent;

[0040] 2) Weigh 3.0 g of a green tea sample with 3% sucrose content roasted in advance in the laboratory, add 150 ml of boiling water and brew for 5 minutes, drain the tea soup, and use it as the tea soup to be tested.

[0041] 3) Take four samples of 1ml of the above-mentioned tea soup and place them in 4 numbered centrifuge tubes respectively. Centrifuge tube 1 does not add adsorbent, centrifuge tube 2 adds 30 mg of activated carbon, centrifuge tube 3 adds 30 mg of cross-linked polyvinylpyrrolidone, centrifuge tube 3 4 Add 25mg cross-linked polyvinylpyrrolidone and 5mg activated carbon;

[0042] After mixing, heat in a water bath at 50°C for 10 minutes and centrifuge;

[0043] 4) Take 8 transparent glass test tubes of the same specificat...

Embodiment 2

[0046] Embodiment 2, the influence of the amount of adsorbent on the color development effect of the tea soup sample containing sucrose

[0047] 1) Weigh 1.0 g of the black tea and green tea samples added with sucrose during the processing and place them in conical flasks respectively, add about 40 mL of boiling water to each, put the conical flasks into an ultrasonic processor for ultrasonic extraction for 5 min; filter out the extract , add 40 mL of boiling water again, and repeat the above-mentioned ultrasonic treatment. Wash the respective tea residues twice with deionized water, combine the two ultrasonic extraction solutions of the same tea sample and the cleaning solution of tea residues, and dilute to 100mL after cooling, as tea soup samples.

[0048] 2) Take 7 centrifuge tubes, put 1mL of each black tea soup sample obtained above, and add different quality adsorbents in turn, the adsorbent is a mixture of cross-linked polyvinylpyrrolidone and activated carbon with a m...

Embodiment 3

[0054] Embodiment 3, standard addition recovery rate experiment

[0055] Prepare reagents and black tea, green tea blank tea soup samples according to the conditions of the aforementioned Example 2, and draw a working curve. In the two kinds of tea soup samples obtained, respectively add sucrose at five concentration levels of 0, 0.05, 0.10, 0.20, 0.30, and 0.60 g / L. The adsorbent is the same as in Example 2, and the amount of adsorbent is 30 mg / 1 mL of tea soup sample; and Determine the recovery of the detection method. The experimental results showed that at the spiked level of 0.05-0.60g / L, the detection recovery rate of the method for sucrose in black tea soup was 103.4%-117.8%, and the detection recovery rate of sucrose in green tea soup was 91.9%-100.5%.

[0056] The above-mentioned concentration level of the added standard in the tea soup was converted into the sucrose content in the dry tea and plotted in Excel, and the fitted linear equation between the added amount ...

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Abstract

The invention discloses a method for rapidly detecting the interference resistance of sucrose externally doped in tea leaves. A cross-linked polyvinylpyrrolidone-activated carbon combination adsorbentis used to remove the interference of a matrix component in tea sample extract to the chromogenic reaction and the detection of resorcinol. The method concretely includes the following steps: sampleextraction, selective adsorption removal of the interference matrix in a sample by using the adsorbent, a chromogenic reaction, and color resolution for qualitative determination or absorbance measurement for quantitative detection, wherein the selective adsorption of the matrix is a key step for detecting the interference resistance. The method realizes rapid qualitative and quantitative determination of sucrose added during tea leaf processing, has the characteristics of high interference resistance, wide application range, simplicity in operation and reliable result, and is especially suitable for rapid qualitative screening and quantitative quantification of sucrose doped in the tea leaves.

Description

technical field [0001] The invention belongs to the field of food detection, and in particular relates to an anti-interference rapid detection method for exogenously added sucrose in tea. Background technique [0002] In recent years, in order to pursue better apparent quality of tea, individual producers have added sucrose to tea from time to time. The sucrose added during tea processing can affect the sensory quality evaluation of finished tea in terms of aroma and color; at the same time, due to the characteristics of sucrose, which is easy to absorb moisture, deteriorate and breed bacteria, it has a greater impact on the quality and safety of tea. Impact. Therefore, the addition of sucrose has attracted more and more attention in the tea quality supervision system and consumers, and the corresponding rapid detection method has become a market demand. In order to adapt to this situation, we have previously developed a method for rapid screening and detection of sucrose ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/31G01N21/78
Inventor 郝振霞金莉莉刘新鲁成银
Owner TEA RES INST CHINESE ACAD OF AGRI SCI
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