Fingerprint spectrum recognition method for Pu'er drying green raw tea and based on chemical components

Abstract

The invention discloses a fingerprint spectrum recognition method for Pu'er drying green raw tea and based on chemical components. The fingerprint spectrum recognition method comprises the following steps: establishing a standard fingerprint spectrum of the Pu'er drying green raw tea; establishing a fingerprint spectrum of tea to be measured in the same way; and comparing the fingerprint spectrum of the tea to be measured and the standard fingerprint spectrum of the Pu'er drying green raw tea, and screening the tea to be measured in accordance with the standard fingerprint spectrum of the Pu'er drying green raw tea. The pretreatment of the samples is simple and convenient, so a lot of manpower labor is not required to be spent. The recognition method for the Pu'er drying green raw tea and based on the whole chemical components has relatively good precision, stability and repeatability, and has high recognition rate.

Description

technical field

[0001] The invention relates to a method for identifying Pu-erh sun-dried green tea, in particular to a method for identifying fingerprints of Pu-er sun-dried green tea based on chemical components. Background technique

[0002] Pu'er tea production areas are widely distributed in Yunnan Province, and the quality of sun-dried green tea produced at different times, different regions, and different years is very different; The stable quality of tea has brought hidden dangers. At present, the identification and quality evaluation of raw tea mostly rely on sensory evaluation. Due to its own limitations, sensory evaluation lacks objective quantitative basis, which has a great impact on the stability of Pu-erh tea quality.

[0003] Fingerprint is a comprehensive and quantifiable means of identification, which has been widely used in many fields such as environmental protection, petroleum exploration, food evaluation, seed detection and variety identification. Pue...

Examples

Embodiment 1

[0030] This embodiment includes the following steps:

[0031] (1) Establishment of standard fingerprint spectrum of Pu-erh sun-dried green tea

[0032] a. Pu'er sun-dried green tea is crushed to 40 mesh, and the sample size n is at least 10;

[0033] b. Weigh 1.0g of tea powder, add 100mL of 80% methanol, 30°C water bath, ultrasonically assisted extraction, 20min, filter paper, wash the filter residue 3 times, combine the filtrate, dilute to 200mL, filter with a 0.22μm filter membrane and set aside;

[0034] c. Adopt Japan SHIMADZULC-20AD high-performance liquid chromatography; SPD6AV adjustable wavelength ultraviolet detector (Shimadzu Corporation); LC-solution chromatography workstation; draw samples to high-performance liquid chromatography for determination, and obtain different origins of Puer sun The chemical map of Qingmao tea; Chromatographic conditions: Chromatographic column: waters-C 18 , 5μm, 4.6mm×250mm; mobile phase: Phase A is 0.03% trifluoroacetic acid, phase...

Embodiment 2

[0052] The tea to be tested in this embodiment is flat green tea. As shown in Table 1, within the retention time of 23 standard fingerprints of sun-dried green tea, compare the chromatographic peak areas of sun-dried green tea and flat green tea. The overlapping rate of the spectrum is above 96.9%, and the similarity calculated by the correlation coefficient and the cosine angle is above 98.5%. However, the overlap rate of the flat green tea and the standard fingerprint is only 65.4%, and the similarity calculated by the correlation coefficient and the cosine angle is 89.4. %, to achieve identification. Other implementations are the same as in Example 1.

Embodiment 3

[0054] The tea to be tested in this embodiment is sun-dried green tea. As shown in Table 1, the overlap rate of sun-dried green tea spectrum and characteristic fingerprint spectrum is above 96.9%, and the similarity is above 98.5%, realizing identification. Other implementations are the same as in Example 1.

[0055] Table 1 The digital standard fingerprint of sun-dried green tea and the discrimination of fried green tea and flat green tea

[0056]

[0057]

[0058] Note: 0 in the table means 0 when 2 significant figures are reserved

[0059] EGC: epigallocatechin; caff: caffeine; (+)C: catechin; EC: epicatechin; EGCG: epigallocatechin gallate; GCG: gallocatechin gallate; ECG : Epicatechin gallate.

technical field

[0001] The invention relates to a method for identifying Pu-erh sun-dried green tea, in particular to a method for identifying fingerprints of Pu-er sun-dried green tea based on chemical components. Background technique

[0002] Pu'er tea production areas are widely distributed in Yunnan Province, and the quality of sun-dried green tea produced at different times, different regions, and different years is very different; The stable quality of tea has brought hidden dangers. At present, the identification and quality evaluation of raw tea mostly rely on sensory evaluation. Due to its own limitations, sensory evaluation lacks objective quantitative basis, which has a great impact on the stability of Pu-erh tea quality.

[0003] Fingerprint is a comprehensive and quantifiable means of identification, which has been widely used in many fields such as environmental protection, petroleum exploration, food evaluation, seed detection and variety identification. Pue...

Examples

Embodiment 1

[0030] This embodiment includes the following steps:

[0031] (1) Establishment of standard fingerprint spectrum of Pu-erh sun-dried green tea

[0032] a. Pu'er sun-dried green tea is crushed to 40 mesh, and the sample size n is at least 10;

[0033] b. Weigh 1.0g of tea powder, add 100mL of 80% methanol, 30°C water bath, ultrasonically assisted extraction, 20min, filter paper, wash the filter residue 3 times, combine the filtrate, dilute to 200mL, filter with a 0.22μm filter membrane and set aside;

[0034] c. Adopt Japan SHIMADZULC-20AD high-performance liquid chromatography; SPD6AV adjustable wavelength ultraviolet detector (Shimadzu Corporation); LC-solution chromatography workstation; draw samples to high-performance liquid chromatography for determination, and obtain different origins of Puer sun The chemical map of Qingmao tea; Chromatographic conditions: Chromatographic column: waters-C 18 , 5μm, 4.6mm×250mm; mobile phase: Phase A is 0.03% trifluoroacetic acid, phase...

Embodiment 2

[0052] The tea to be tested in this embodiment is flat green tea. As shown in Table 1, within the retention time of 23 standard fingerprints of sun-dried green tea, compare the chromatographic peak areas of sun-dried green tea and flat green tea. The overlapping rate of the spectrum is above 96.9%, and the similarity calculated by the correlation coefficient and the cosine angle is above 98.5%. However, the overlap rate of the flat green tea and the standard fingerprint is only 65.4%, and the similarity calculated by the correlation coefficient and the cosine angle is 89.4. %, to achieve identification. Other implementations are the same as in Example 1.

Embodiment 3

[0054] The tea to be tested in this embodiment is sun-dried green tea. As shown in Table 1, the overlap rate of sun-dried green tea spectrum and characteristic fingerprint spectrum is above 96.9%, and the similarity is above 98.5%, realizing identification. Other implementations are the same as in Example 1.

[0055] Table 1 The digital standard fingerprint of sun-dried green tea and the discrimination of fried green tea and flat green tea

[0056]

[0057]

[0058] Note: 0 in the table means 0 when 2 significant figures are reserved

[0059] EGC: epigallocatechin; caff: caffeine; (+)C: catechin; EC: epicatechin; EGCG: epigallocatechin gallate; GCG: gallocatechin gallate; ECG : Epicatechin gallate.

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