Distinguishing method of Guangdong Hakka pan-fired green tea
By detecting the non -volatile components of Hakka -fried green tea, accurately distinguish the tea of different places, solve the problem that it is difficult to identify tea in different places in existing technology, and achieve the unified standards and quality improvement of tea processing.
Patent Information
- Application Number
- CN202410839280.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2025-01-28
AI Technical Summary
The prior art is difficult to quickly and accurately identify Hakka fried green tea from different origins, resulting in a lack of unified standards for tea processing and difficult to fix quality and flavor.
Non -volatile ingredients such as Huangdan fried green tea, plums fried green tea, and cool green tea such as crickets such as catexine, catechins have no menicate, catechin, and their components. To distinguish the Hakka green tea.
The accurate distinction of Hakka green tea in different places has provided the basis of targeted processing, and effectively improved the quality of tea.
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Figure CN119375437A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of Guangdong Hakka green tea identification, and in particular to a method for distinguishing Guangdong Hakka stir-fried green tea. Background Art
[0002] Green tea is one of the most consumed beverages in the world. Its success as a beverage is inseparable from its excellent health functions and unique flavor quality. The quality of green tea is mainly reflected in its taste and aroma. In order to ensure the quality of green tea, different processing methods are required for different qualities of green tea.
[0003] Hakka fried green tea is a representative specialty of the Hakka region in China. As one of the eight famous historical teas, the history of Hakka fried tea can be traced back to the Wei and Jin Dynasties 1,700 years ago. One of the typical representatives is the Guangdong Hakka fried green tea in the tea area of South China. In recent years, the output and area of traditional Hakka fried green tea have accounted for more than 40% of the total tea output in Guangdong Province, with a rapid development speed and great potential. While the output and area of traditional Hakka fried green tea continue to rise, it has also caused problems such as the lack of unified standards for tea processing and the difficulty in fixing the quality and flavor. In actual production, the same variety of green tea will be purchased from different origins and then processed. However, the different planting regional environments will affect the substances contained in Hakka fried green tea. At present, there is no effective way to quickly identify green tea from different origins. Hakka fried green tea purchased from various places is more processed according to unified standards, which makes it difficult to fix the quality and flavor of green tea, which is not conducive to targeted improvement of the taste quality of green tea. Summary of the invention
[0004] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for distinguishing Guangdong Hakka fried green tea. The method for distinguishing Guangdong Hakka fried green tea finds the significant differences in the content of specific non-volatile substances between Hakka fried green teas from different regions and can accurately distinguish the corresponding Hakka fried green teas, thus having the advantage of accurate distinction effect.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] Provide a method for distinguishing Guangdong Hakka fried green tea, Huangdan fried green tea, Meizhan fried green tea, and Qingliangshan fried green tea, including the following steps:
[0007] Step 1, detecting the corresponding non-volatile components theanine, epicatechin gallate, catechin and the content of each component in Huangdan fried green tea, Meizhan fried green tea and Qingliangshan fried green tea;
[0008] Step 2: Differentiate Hakka stir-fried green tea by judging the content of the components, including:
[0009] When the content of theanine is the highest, the Hakka stir-fried green tea is judged to be Qingliangshan stir-fried green tea.
[0010] When the catechin content is the highest, the Hakka stir-fried green tea is judged to be Meizhan stir-fried green tea.
[0011] When the epicatechin gallate content is the highest, the Hakka stir-fried green tea is judged to be Huangdan stir-fried green tea.
[0012] In some embodiments, in step 1, the non-volatile components epigallocatechin, epigallocatechin gallate, catechin gallate and their corresponding contents of Huangdan stir-fried green tea, Meizhan stir-fried green tea and Qingliangshan stir-fried green tea are also detected.
[0013] In step 2, when the theanine content is high and the epigallocatechin content is the highest, the Hakka stir-fried green tea is judged to be Qingliangshan stir-fried green tea.
[0014] When the catechin content and the catechin gallate content are the highest, the Hakka stir-fried green tea is judged to be Meizhan stir-fried green tea.
[0015] When the epicatechin gallate content and the epigallocatechin gallate content are the highest, the Hakka stir-fried green tea is judged to be Huangdan stir-fried green tea.
[0016] In some embodiments, the maximum difference between the theanine content of Qingliangshan fried green tea and the theanine content of Huangdan fried green tea and Meizhan fried green tea can reach 1%.
[0017] In some embodiments, the maximum difference between the epigallocatechin content of Qingliangshan stir-fried green tea and the epigallocatechin content of Huangdan stir-fried green tea and Meizhan stir-fried green tea can reach 0.82%.
[0018] In some embodiments, the maximum difference between the epicatechin gallate content of Huangdan stir-fried green tea and the epicatechin gallate content of Qingliangshan stir-fried green tea and Meizhan stir-fried green tea can reach 0.44%.
[0019] In some embodiments, the maximum difference between the epigallocatechin gallate content of Huangdan stir-fried green tea and the epigallocatechin gallate content of Qingliangshan stir-fried green tea and Meizhan stir-fried green tea can reach 1.54%.
[0020] In some embodiments, the maximum difference between the gallic catechin content of Meizhan stir-fried green tea and the gallic catechin content of Qingliangshan stir-fried green tea and Huangdan stir-fried green tea can reach 0.21%.
[0021] In some embodiments, the maximum difference between the catechin gallate content of Meizhan stir-fried green tea and the catechin gallate content of Qingliangshan stir-fried green tea and Huangdan stir-fried green tea can reach 0.23%. The beneficial effects of the method for distinguishing Guangdong Hakka stir-fried green tea of the present invention are as follows:
[0022] The method for distinguishing Guangdong Hakka stir-fried green tea of the present invention finds that the non-volatile components theanine content, ECG content, and GC content are different among Guangdong Huangdan stir-fried green tea, Meizhan stir-fried green tea, and Qingliangshan stir-fried green tea. By judging the component content, the Hakka stir-fried green tea can be accurately distinguished. When the high theanine content is the highest, the Hakka stir-fried green tea is judged to be Qingliangshan stir-fried green tea; when the GC content is the highest, the Hakka stir-fried green tea is judged to be Meizhan stir-fried green tea; when the ECG content is the highest, the Hakka stir-fried green tea is judged to be Huangdan stir-fried green tea. By accurately distinguishing Hakka stir-fried green tea, Hakka stir-fried green tea can be processed in a targeted manner, and the quality of Hakka stir-fried green tea can be effectively explored. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 The changes of caffeine (A), theanine (B) and catechin (CI) contents in three kinds of Hakka stir-fried green tea HD, MZ and QL, where the abbreviations of each component are as follows: catechin (C); epicatechin (EC); gallocatechin (GC); epigallocatechin (EGC); epicatechin gallate (ECG); catechin gallate (GCG); epigallocatechin gallate (EGCG). SPSS univariate analysis confirmed significant differences (p<0.05), and the values are the mean ± SD of all replicates.
[0024] Figure 2 This is the multivariate statistical analysis of the metabolites in three types of Hakka fried green tea: (a) PCA score graph; (b) OPLS-DA score graph; (c) VIP score graph.
[0025] Figure 3 is the PCA score of the volatile component.
[0026] Figure 4 is a heat map analysis of volatile aroma.
[0027] Figure 5 It is a heat map analysis of key volatile substances. DETAILED DESCRIPTION
[0028] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.
[0029] Material
[0030] Huangdan stir-fried green tea (HD) comes from Huangdan in Meizhou, Guangdong, Meizhan stir-fried green tea (MZ) comes from Meizhan in Meizhou, Guangdong, and is the autumn tea of 2020, provided by Yida Pharmaceutical Co., Ltd. in Jiexi County, Jieyang City, Guangdong Province; Qingliangshan stir-fried green tea (QL) comes from Qingliangshan in Guangdong, and is the autumn tea of 2020, provided by Runqi Cultural Technology Development Co., Ltd. in Meizhou City, Guangdong Province. These three kinds of tea are processed and produced according to the traditional Hakka stir-fried green processing procedures: fresh leaf picking-withering-killing-rolling-stir-frying-huiguo (drying tea leaves, increasing aroma and taste, and improving the color of dry tea).
[0031] Determination of non-volatile compounds
[0032] Caffeine determination
[0033] According to the Chinese national standard GB / T 8312-2013 “Determination of caffeine in tea”, the caffeine component was detected by HPLC-UV / Vis spectroscopy. The instrument was Waters Alliance E2695 equipped with a 2489 UV / Vis detector (Waters Technologies, Milford, MA, USA).
[0034] Caffeine standards were purchased from Beijing Weiye Research Institute of Metrology and Technology (Beijing, China), and Theanine standards were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China).
[0035] Theanine determination
[0036] Theanine content was detected by HPLC-UV / Vis spectroscopy according to the Chinese national standard GB / T 23193-2017 "Determination of theanine in tea" (Mei et al. 2022). Theanine standards were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China).
[0037] Catechin component determination
[0038] Referring to the Chinese national standard GB / T 8313-2018 "Determination of tea polyphenols and catechins in tea" (Mei et al. 2022), HPLC-UV / Vis spectroscopy was used for detection. The instrument was Waters Alliance E2695 equipped with a 2489UV / Vis detector (Waters Technologies, Milford, MA, USA). Catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), epicatechin gallate (ECG), gallocatechin gallate (GCG), and epigallocatechin gallate (EGCG) standards were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China).
[0039] GC-MS analysis of volatile compounds
[0040] Volatile compounds were determined and analyzed using headspace solid phase microextraction / gas chromatography-mass spectrometry (HS-SPME / GC-MS). The instrument used was an Agilent 1890B gas chromatograph coupled with a 5977A massspectrometer (Agilent, Santa Clara, CA, USA), and the chromatographic column model was HP-5MS (30m×0.25mm×0.25μm film thickness). The quantitative analysis steps were as follows: First, 2.0g of dry tea sample and 0.0864g of ethyl decanoate were added to a 40ml headspace bottle, which was quickly sealed and preheated at 80° for 15 minutes. Second, a divinylbenzene / carboxylic acid / polydimethylsiloxane (DVB / CAR / PDMS) fiber (inner diameter 50 / 30μm, length 2cm) (Supelco, Darmstadt, Germany) was inserted into the headspace bottle and extracted at 80° for 40 minutes. Third, after the extraction is completed, the SPME fiber is inserted into the GC injection port (250°, 3 min). Fourth, the specific instrument parameters for GC-MS analysis refer to Peifen Chen et al. (Chen et al. 2022). Qualitative analysis steps: The retention index (RI) and mass spectrum matching factor are used for qualitative analysis of substances. The retention index was calculated based on the retention time of normal alkanes (C9-C21) using the formula RI = 100n + 100[RT(x)-RT(n)] / [RT(n+1)-RT(n)], where RT(x) is the retention time of compound x, RT(n) and RT(n+1) are the retention times of alkanes with carbon numbers n and n+1 eluting immediately before and after compound x, respectively (Chen et al. 2022), and compared with the NIST 11 database query value (https: / / webbook.nist.gov / chemistry / name-ser / ). Compound matches were accepted when the calculated RI was less than 15, or if the mass spectral match factor was more than 90.
[0041] Test results
[0042] Non-volatile component content and difference analysis
[0043] Huang Dan, Mei Zhan, Qingliangshan green tea caffeine, theanine, catechin monomer content Figure 1 as shown.
[0044] There are significant differences in theanine, ECG, EGC, EGCG, GC, and GCG contents among the three types of Hakka stir-fried green tea. For example, QL has the highest theanine content (1.19%) and is significantly higher than HD (0.34%) and MZ (0.19%), with the maximum difference being 1%. It shows that HD has the highest ECG (1.50%) and EGCG (5.56%) contents, with the maximum differences being 0.44% and 1.54%, respectively; MZ has the highest GC (0.34%) and GCG (0.52%) contents, with the maximum differences being 0.21% and 0.23%, respectively; QL has the highest EGC content (2.62%), with the maximum difference being 0.82%. In addition, there are significant differences in the caffeine content of HD and the EC content of QL among the three types of Hakka stir-fried green tea, but the differences in content are not significant, and there is no significant difference in C content.
[0045] Multivariate statistical analysis of non-volatile components
[0046] In order to further explore the relationship between non-volatile components and the quality of Hakka stir-fried greens, the PCA analysis method was used to summarize the differences in non-volatile components between the three types of Hakka stir-fried greens ( Figure 2 ). The cumulative variance contribution rate of the first two principal components is 97.5% (PC1 = 60.5%, PC2 = 37.0%), with a 95% confidence region, which can effectively reflect the relationship between different stir-fried greens. The overlapping part in the PCA diagram represents that the three types of Hakka stir-fried greens have a certain degree of correlation in non-volatile components, but overall HD, MZ, and QL are concentrated in different quadrants, and the distinction is obvious, indicating that the three types of stir-fried greens have obvious differences in non-volatile components, which is consistent with the results of univariate analysis.
[0047] In order to further explore the non-volatile components that determine the quality differences of different Hakka stir-fried greens, the OPLS-DA model was used to quickly and accurately analyze the differences between groups by amplifying the differences between groups and reducing the differences within groups, filtering out information irrelevant to classification (Mao Honglin et al. 2022). The variable importance in project (VIP) score was obtained according to the OPLS-DA model. Compounds with a VIP value greater than 1 can be used as key compounds to distinguish between the two groups of variables. The results showed that the VIP values of EGCG (VIP = 1.4833) and Theanine (VIP = 1.2242) were greater than 1 (Table 1), indicating that these two components have a high contribution rate in distinguishing quality differences.
[0048] Multivariate statistical analysis of volatile components
[0049] Volatile identification and analysis
[0050] As shown in Table 1, a total of 71 volatiles were detected in this study, including 46 HD, 35 MZ, and 50 QL. Olefin compounds were the most numerous (23 species), and their total amount accounted for 12.39% to 16.57% of all aroma components. HD and QL alcohol compounds had the highest relative content, and their total amount accounted for 25.10% to 34.93% of all aroma components. MZ had the highest olefin content (35.8%).
[0051] In the tea samples, 14 volatiles were unique to HD [nerolidol, α-bimanol, 2-butyl-2-octenal, methylheptenone, tetrahydro-6-(2-pentenyl)-2H-2-pyrone, undecene, trans-α-bergamotene, bisabolene, (3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene, benzoyl benzoate, methyl jasmonate, 1,2,3,4-tetrahydro-1,6-dimethyl-4-(1-methylethyl)-naphthalene, decamethylcyclopentasiloxane, 1-methylene-1H-indene], and 6 volatiles were unique to MZ [2-tetradecene , α-cedrene, 7-methoxy-2,2-dimethyl-3-chromene, β-bisabolene, caryophyllene oxide, methyl tetradecanoate], and 14 volatiles were unique to QL [benzyl alcohol, α-ionone, 2,4-dimethylstyrene, α-pinene, α-farnesene, α-didehydrocubene, methyl linoleate, methyl stearate, 1,6-dimethyl-4-(1-methylethyl)naphthalene, 2-methylnaphthalene, naphthalene, 2-methyl-4-aminophenol, coumarin, 2,6-di-tert-butyl-o-benzoquinone-4-oxime], indicating that the volatile composition and component content of the three Hakka stir-fried greens were significantly different.
[0052] Table 1 Summary of volatile components of three types of Hakka fried green tea
[0053]
[0054]
[0055]
[0056] PCA, heat map analysis
[0057] From the PCA scores of the three Hakka stir-fried green aroma components, we can see that ( Figure 3 ), PC1 = 50.9%, PC2 = 42.2%, the first two principal components contain 93.1% of the information in the data set, and the model is reliable. The results show that HD, MZ, and QL green teas have overlapping parts, which means that there is a certain degree of correlation in the volatile components, but they are generally concentrated in different quadrants, which is obvious, indicating that there are obvious differences in the aroma components of HD, MZ, and QL green teas.
[0058] In order to more intuitively distinguish the differences in the volatile composition of the three types of Hakka stir-fried greens, HCA analysis was performed on the aroma components. It can be seen from the figure that the aroma components are clustered into three categories, among which HD-1, HD-2, and HD-3 are clustered into one category, MZ-1, MZ-2, and MZ-3 are clustered into one category, and QL-1, QL-2, and QL-3 are clustered into one category. This shows that the volatile component composition of the three types of Hakka stir-fried greens is significantly different, which is consistent with the above conclusion.
[0059] Key differential volatile component analysis
[0060] OAV reveals the contribution of aroma components to the food aroma system from the two dimensions of concentration and threshold, and provides an effective technical means for characterizing the key aroma components of food (Chen Zhifei et al. 2018). Generally speaking, compounds with OAVs ≥ 1 contribute positively to the characteristic aroma (Guo et al. 2021; Hu et al. 2022). Therefore, based on OAVs ≥ 1 and VIP ≥ 1, 17 key aroma substances were screened out from 71 aromas of three types of Hakka stir-fried greens (Table 2), including 3 alcohol compounds, 2 aldehyde compounds, 4 ketone compounds, 1 olefin compound, 2 ester compounds, and 5 other compounds. In order to more intuitively analyze the differences in key aroma substances, a feature clustering heat map was constructed ( Figure 5 ), the results showed that HD had 4 unique aroma substances, all of which were related to floral aroma, MZ had 3 unique aroma components, which showed partial floral aroma, sweet aroma, and green bitter aroma, and QL had 7 unique aroma components, which showed a mixture of multiple aroma types. This shows that these components have an important contribution to the formation of Hakka stir-fried green aroma and the difference in quality.
[0061] Among the 17 aroma components, there are 10 substances that show floral aroma, 6 of the remaining 7 have positive aroma contributions, and 1 shows an unfavorable aroma (Naphthalene: Pungent, dry, tarryodore); there are 3 compounds with OAV ≥ 300, all of which show floral aroma, including Geranylacetone (1212.77-4402.80) of flower, jasmon (HD: 331.53) of Jasmine Scented, and β-ionone (2478.33-6774.91) of floral, woody; the compound with 100 ≥ OAV> 300 is Decanal (130.04-164.40) of fatty, citrus; There are 3 compounds with 50≥OAV>100, including Linalool (69.67~83.36) with floral, citrusy, Naphthalene (86.20) with punchent, dry, tarryodore, and α-Ionone (81.23) with violet, flower; there are 10 compounds with 1≥OAV>50, including Geraniol (11.90-17.92) with rose-like, citrus-like, Nerolidol (HD:34.68) with woody, flowery, β-Cyclocitral (14.42~37.24) with citrus-like, jasmon (QL:46.96) with jasmine scent, Caryophyllene oxide (37.88) with sweet fruity aroma, and Methyl salicylate (1.90~2.92) with mint-like.
[0062] &Jasmine Scented Methyl jasmonate(12.56)&Licorice-like 1,2-Dihydro-1,1,6-trimethylnaphthalene(5.67~36.68)&Floral,violet,powdery’s 1,2,3,4-Tetrahydro-1,1,6-trimethylnaphthalene(6.05~14.88)&flower’s Indole(4.5-36.77)
[0063] &milky, sweet, green and bitter Coumarin (QL: 5.08).
[0064] Table 2 Main volatile substances
[0065] Comparison of different varieties of Hakka stir-fried green tea
[0066] QL has a higher theanine content, and Xianhu has higher ECGC and catechin content than other varieties. As a local variety in Guangdong, QL has a lower yield than the introduced national tea tree varieties HD and MZ, but from the perspective of internal substances, QL has the highest theanine content (1.20%) and the most aroma types (50) in this study. Based on this result, it can be inferred that the difference in regional environment is one of the important factors affecting the quality of Hakka stir-fried green tea. Therefore, in the future introduction of tea trees, we should fully understand the biochemical composition and characteristics of the varieties, as well as the climate, altitude, soil conditions and other factors of the introduction area, and improve its processing technology and cultivation methods in a targeted manner, which may significantly improve the taste of Hakka stir-fried green tea.
[0067] Table 3 Comparison of the main biochemical components of different Hakka stir-fried greens
[0068]
[0069] The present invention uses a multivariate statistical analysis method to analyze the non-volatile and volatile components of three types of Hakka stir-fried green tea. The results show that there are differences in the non-volatile and volatile components of the three types of Hakka stir-fried green tea. Theanine and EGCG have a high contribution rate in distinguishing quality differences. A total of 71 aroma components were identified in Hakka stir-fried green tea, among which olefin compounds are the most numerous (23 species), HD and QL have the highest relative content of alcohol compounds (25.10% to 34.93%), and MZ has the highest olefin content (35.8%). Based on OAVs≥1 and VIP≥1, 17 key aroma substances were screened out. Among the key aromas, Linalool, Geraniol, Nerolidol, α-Ionone, β-ionone and other aroma components show floral and fruity aromas. The interaction of these substances may be the key to the unique quality of Hakka stir-fried green tea. China is the country with the largest tea production in the world, and green tea accounts for about 60% of the entire tea industry. With the development of modern diversification, Hakka fried green tea has developed rapidly in recent years due to its unique fried rice aroma. Therefore, studying the differences in the quality components of Hakka fried green tea and digitizing its quality has broad room for improvement and application prospects in terms of quality improvement, processing and production, and flavor innovation of Hakka fried green tea.
[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for distinguishing Guangdong Hakka stir-fried green tea, characterized in that: The distinguishing method is used to distinguish Huangdan stir-fried green tea, Meizhan stir-fried green tea, and Qingliangshan stir-fried green tea, and comprises the following steps: Step 1, detecting the corresponding non-volatile components theanine, epicatechin gallate, catechin and the content of each component in Huangdan fried green tea, Meizhan fried green tea and Qingliangshan fried green tea; Step 2: Differentiate Hakka stir-fried green tea by judging the content of the components, including: When the content of theanine is the highest, the Hakka stir-fried green tea is judged to be Qingliangshan stir-fried green tea. When the catechin content is the highest, the Hakka stir-fried green tea is judged to be Meizhan stir-fried green tea. When the epicatechin gallate content is the highest, the Hakka stir-fried green tea is judged to be Huangdan stir-fried green tea.
2. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 1, characterized in that: In step 1, the corresponding non-volatile components of Huangdan stir-fried green tea, Meizhan stir-fried green tea, and Qingliangshan stir-fried green tea, epigallocatechin gallate, and catechin gallate, and their corresponding contents, are also detected. In step 2, when the theanine content is high and the epigallocatechin content is the highest, the Hakka stir-fried green tea is judged to be Qingliangshan stir-fried green tea. When the catechin content and the catechin gallate content are the highest, the Hakka stir-fried green tea is judged to be Meizhan stir-fried green tea. When the epicatechin gallate content and the epigallocatechin gallate content are the highest, the Hakka stir-fried green tea is judged to be Huangdan stir-fried green tea.
3. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 2, characterized in that: The maximum difference between the theanine content of Qingliangshan fried green tea and the theanine content of Huangdan fried green tea and Meizhan fried green tea can reach 1%.
4. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 2, characterized in that: The maximum difference in epigallocatechin content between Qingliangshan fried green tea, Huangdan fried green tea, and Meizhan fried green tea can reach 0.82%.
5. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 2, characterized in that: The maximum difference between the epicatechin gallate content of Huangdan fried green tea and the epicatechin gallate content of Qingliangshan fried green tea and Meizhan fried green tea can reach 0.44%.
6. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 2, characterized in that: The maximum difference between the epigallocatechin gallate content of Huangdan fried green tea and the epigallocatechin gallate content of Qingliangshan fried green tea and Meizhan fried green tea can reach 1.54%.
7. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 2, characterized in that: The maximum difference between the gallic catechin content of Meizhan fried green tea and the gallic catechin content of Qingliangshan fried green tea and Huangdan fried green tea can reach 0.21%.
8. The method for distinguishing Guangdong Hakka stir-fried green tea according to claim 2, characterized in that: The maximum difference between the catechin gallate content of Meizhan fried green tea and the catechin gallate content of Qingliangshan fried green tea and Huangdan fried green tea can reach 0.23%.