# Research on Functional Components and Bioactivity in Tea in the Context of Big Data

Authors: Jinwu He; Weiwei Fan
Journal: Advances in Multimedia
 (2022)

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## Abstract

The introduction of the concept of big data has provided considerable convenience in all walks of life, and the field of tea research is no exception. With the rapid development of Internet technology and economic aspects, the traditional methods of functional tea research can no longer meet the growing demand, and it is necessary to change the concept to learn the latest biological activity research methods. In this paper, we use Mao Jian tea from the Lvliang Mountains as an example and use the big data method to collect and analyze data. The main functional components of Mao Jian tea were studied, and some of the functional components and biological activities in Mao Jian tea from the Lvliang Mountains were compared with those of Pu’er tea, black tea, and green tea using UV spectrophotometry. The results showed that the maximum amount of flavonoids in the tea broth reached 43.29 mg/g when the brewing temperature was 90°C, the ratio of tea to water was 1 : 120, the brewing time was 20 min, and the Lvliang Mao Jian tea brewed under this condition had the highest activity, in which the flavonoid health function played the most effective role.


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## Body

## 1. Introduction

Tea drinking and tea culture have been practiced in China for thousands of years. China has a wide variety of tea leaves and abundant resources and is a major tea producer and exporter in the world. According to the fermentation situation, tea can be divided into nonfermented tea, semifermented tea, fully fermented tea, and postfermented tea [1]. As one of the world’s top three beverages, tea not only has a good taste and low calorie content but also has many health functions, such as antioxidant [2, 3], antiatherosclerosis [4, 5], and neuroprotective [6]. Tea leaves and its extracts have good antioxidant capacity [7], but most of the research has focused on the water-soluble fraction [8], and less on its alcoholic extracts. The extracts of tea leaves can be made through a certain process to enhance their health benefits, and the functional components in tea can be further investigated by making full use of low quality tea materials such as tea powder and tea grinds through the extraction process.With the development of information technology, people’s lives have undergone tremendous changes. In the current situation, data is an important means of production, and the innovative technology of big data will become a driving force for future productivity improvements. Big data is leading to disruptive changes in people’s productive lives, and the business philosophy and management behaviour of enterprises are also changing. On the one hand, the era of big data has brought various impacts to enterprises, forcing them to reform in order to cope with various challenges, and integrating into the era of big data has become an inevitable choice for enterprises. On the other hand, enterprises can make use of the convenience provided by big data, give full play to its potential value, cultivate relevant capabilities, seize the opportunities brought by digital transformation, and be among the market leaders. If tea enterprises want to operate in the era of big data for a long time, they must seek breakthroughs and innovations, enhance their competitiveness, and continuously adapt themselves to the current economic environment. This also means that in order to adapt to survive, tea enterprises are more or less equipped with certain big data capabilities.In recent years, the state has attached great importance to the construction of smart agriculture and digital agriculture. The application of big data can provide agricultural producers with real-time, accurate, and perfect agricultural data information and relevant policies and regulations [9]. China is the world’s largest tea producing and consuming country, and the tea industry is also an important traditional advantageous industry in China, but the production mode is still relatively traditional [10], and the digital application level of the industry is still relatively low [11]. The main manifestations are as follows: first, it is difficult to collect data, because the tea industry chain is long and involves many business entities, it is difficult to collect data, and the collection standard system is incomplete, which leads to the lack of basic data of the tea industry, and the existing data is not systematic enough to support the needs of high-quality development of the industry. Second, the existing data lack of effective unified management platform, the existing and tea industry-related data resources scattered in the Internet terminals, no data centre platform specifically for the field of tea industry, resulting in the tea industry data integration difficulties. Third, the lack of tea industry chain data decision-making platform cannot make the existing data to play a role.In order to meet the urgent need for the tea industry to adopt big data technology, the Ministry of Agriculture and Rural Affairs issued a notice on the urgent declaration of the 2019 digital agriculture construction pilot project. Through the preliminary construction, the project now has the ability to collect, analyze, and publish data, with the Tea Number APP as the data collection terminal, which has significantly improved the efficiency and quality of data collection. Consumption trend data, e-commerce data, and public opinion monitoring data have obvious auxiliary decision-making ability, a comprehensive grasp of the tea industry annual operating rules, industrial policy formulation, and guidance for scientific decision-making began to play a role. The data collection platform can significantly improve the aggregation capacity of tea industry data and has a better performance compared to traditional methods. The platform provides a solid foundation for the study of functional components and bioactivities in tea leaves.The functional components in tea mainly include tea polyphenols, tea pigments, and tea polysaccharides. At present, the research on tea functional components such as tea polyphenols and tea pigments at home and abroad mainly focuses on their improvement of human physiological functions. Liu [12] also showed that tea polyphenols have the ability to inhibit the deadhesive and adhesive processes of tumor cells, thus inhibiting cell proliferation, blocking the cell cycle, inducing apoptosis, and inhibiting tumor production and metastasis. Li et al. [13] studied the effects of tea polyphenols on the expression of proliferating cell nuclear antigen (PCNA) and neural cell adhesion factor in a human lung hypermetastatic adenoid cystic carcinoma cell line and concluded that tea polyphenols could affect ACC-M cell growth by inhibiting PCNA expression and promoting NCAM expression. After the effect of tea polyphenols, most of the ACC-M cells gradually lost their original wall-adherent morphology, the cells were wrinkled, the cells became smaller and rounder, the cell gap gradually increased, and the number of divisions decreased.In addition, tea polyphenols have been shown to have a significant antiplaque effect [14], and tea polyphenol containing toothpastes have been shown to have a significant effect in removing garlic odour from the mouth [15]. Sabu and Smitha [16] found that tea polyphenols inhibited or lowered blood glucose in normal rats and diabetic rats. At the same time, some domestic scholars also showed that tea polyphenols could inhibit the increase of blood glucose in diabetic rats after oral administration of sucrose and starch, thus improving their glucose tolerance, and also increased the blood insulin level in diabetic rats. It even alleviated and inhibited the chance of diabetic nephropathy in diabetic rats [17, 18].Tea polyphenols also have good antioxidant properties, and their antioxidant capacity is 3-9 times stronger than that of VR, BHT, and BHA [19], which have good antioxidant and skin care effects. At the same time, the amino acids, proteins, vitamins, and mineral elements in tea can also provide good nutrients for the skin, and some scholars in China have conducted studies on the use of waste tea to prepare facial cleansers, skin creams, and sunscreen products [20, 21].Tea pigments are a group of water-soluble phenolic pigments in tea leaves, which have significant anticoagulant, profibrinolytic, and antiatherosclerotic effects. Wang et al. [22] studied the antimutagenic function of tea pigments. The results showed that tea pigments could reduce the incidence of tumors in rats under UV light induction. Steel et al. [23] studied the tumor inhibitory function of tea pigments and showed that tea pigments had a strong inhibitory effect on tumor metastasis in murine mammary gland tissue and respiratory epithelial cells. Some foreign scholars have reported that tea pigments have the ability to significantly improve moderate hypertension and prevent cardiovascular diseases in adults [24]. Studies by many scholars in China have also shown that tea pigments have good modulating effects on blood lipid levels in patients with coronary heart disease, atherosclerosis, hyperlipidemia, essential hypertension, and other diseases [25].Tea polysaccharide is a kind of acidic glycoprotein, which is the abbreviation of the biologically active complex polysaccharide in tea leaves. Because of its complex conformation, its biological activity also varies. Tea polysaccharides can improve the antioxidant capacity of athletes through direct oxidative modification of their protein components, activation of antioxidant enzyme activity by trace elements, and improvement of antioxidant quality by aldose components, thus promoting anaerobic exercise.In recent years, with the increasing awareness of food safety and the rise of tea drinking, health food products with health and medicinal functions and containing active ingredients from tea are increasingly popular among consumers. The main functional ingredients contained in tea have good health effects on human body, but how to standardize and refine the rules for the review of the production license of tea-containing foods and tea-containing health products is still a major problem, and how to reasonably exploit the functional ingredients in tea that have been proven to have health functions still needs to be studied and explored in depth. In this paper, the functional components and bioactivities in tea are investigated based on the big data method, taking Mao Jian tea from Lvliang Mountain Range as an example. The optimum conditions for bioactivity in tea were investigated.


## 2. Analysis of Functional Ingredients

Due to its unique production value, tea leaves are inherently rich in a variety of bioactive substances. These bioactive substances have a close relationship with each other and are also directly related to their bioactive substance content. In this paper, the functional components of Mao Jian tea, green tea, black tea, and Pu’er tea from the Lvliang mountain range were compared and analyzed by screening flavonoids, caffeine, tea polyphenols, tea polysaccharides, free amino acids, and moisture as indicators. By comparing the functional composition of Mao Jian tea of Lvliang Mountains with other speciality teas, we have a preliminary understanding and judgment of Mao Jian tea of Lvliang Mountains and provide scientific data to support the possible functional value of the health functional components of Mao Jian tea of Lvliang Mountains. It will also provide a theoretical basis for setting the quality level of Lvliang Mao Jian tea. The study of functional components and bioactivity in tea based on big data is shown in Figure1.Figure 1
Schematic diagram of the study of functional components and biological activity of tea leaves.


### 2.1. Materials and Equipment

#### 2.1.1. Experimental Materials and Main Reagents

Materials are Mao Jian tea from the Lvliang Mountains, Pu’er tea (from Yunnan), black tea (from Anhui), and green tea (from Jiangsu) that were all purchased from local supermarkets.Reagents are sodium nitrite, aluminium nitrate, sodium hydroxide, rutin standard, anhydrous ethanol, distilled water, basic lead acetate, concentrated hydrochloric acid solution, concentrated sulphuric acid solution, caffeine standard, methanol, sodium carbonate, forinol reagent, gallic acid standard, glutamic acid standard, disodium hydrogen phosphate dodecahydrate, potassium dihydrogen phosphate, hydrated ninhydrin, stannous chloride, glucose, and phenol.


#### 2.1.2. Apparatus and Equipment

Apparatus and equipment are BSA224S analytical balance, UV-1600 UV-Visible spectrophotometer, HK-02A 100 g hand-held grinder, UPT-I-10 T ultrapure water apparatus, DZKW-D-2 electric thermostatic water bath, 101-2AB electric blast drying oven, KQ-300DE ultrasonic instrument, and SC-3610 low-speed centrifuge.


### 2.2. Experimental Methods

#### 2.2.1. Determination of Flavonoids

(1) Sample Processing. Dry the crushed 40-mesh sieved Lvliang Mountain Mao Jian tea and other specialty teas to a constant weight. Weigh 1 g of powdered Lvliang Mao Jian tea and other specialty teas in a conical flask, add ethanol at a volume of 1 : 60 of tea mass: 80% (V/V) ethanol solution, and sonicate for 25 min and then filter to obtain the solution to be measured.(2) Standard Curve Plotting. To analyze the effect of different times on the curve plotting, we first pipetted 10 mL of the rutin control solution and added the reactant to this solution as required. After preparation, the reaction was allowed to stand for 6 min, 6 min, and 20 min after each colour development step. 510 nm was chosen as the detection wavelength for all three experiments.(3) Determination of the Sample. 0.5 mL of the solution to be measured was transferred into a 25 mL cuvette, the solution was added according to the required addition procedure and mixed well to obtain the colour development solution, and λ=510nm was selected as the detection wavelength. The formula for calculating the flavonoid content was as follows.
(1)Flavonoidcontentmg/g=C×V1×V2/V3m,where C is the corresponding amount of rutin calculated from the measured absorbance A in mg/mL. V1 is the volume before the addition of the reactant in mL. V2 is the total volume in mL. V3 represents the volume of the assay liquid removed in mL. m represents the mass of the tea powder sample weighed in g.


#### 2.2.2. Determination of Caffeine

The process consists of two main parts. (1) Preparation of reagents. The standard solution of lead acetate, concentrated hydrochloric acid, and concentrated sulphuric acid was prepared according to the standard; and the standard solution of caffeine and the solution to be measured were prepared, respectively. (2) Determination procedure. A standard curve of caffeine was prepared, and the sample to be tested was measured. Equation (2) is the calculation method for caffeine content.
(2)Caffeinecontent=C2×V2/1000×25m×ω×100%,where C2 is the concentration of caffeine corresponding to the measured absorbance A in mg/mL. V2 is the volume of the test liquid removed in mL. m indicates the amount of sample in grams g. ω is the dry matter content of the tea sample weighed in %.


#### 2.2.3. Determination of Tea Polyphenols

(1) Reagent Preparation. Florinol, methanol, and sodium carbonate were prepared to the required concentrations and labelled as required, and then, the gallic acid standard stock solution and the solution to be measured were prepared according to the experimental needs.(2) Determination Steps. λ=765nm, standard curve of gallic acid and sample to be measured, and 3 replicate experiments to take the average value. The formula for the calculation of tea polyphenol content is shown in the following equation.
(3)CTP=A−A0×V×d×100SLOPEStd×ω×106×m,whereCTP indicates the tea polyphenol content, A is the absorbance of the sample test solution, A0 is the absorbance of the reagent blank, SLOPEStd indicates the slope of the standard curve, m is the sample mass in g, V is the total amount of mother liquor in mL, and d indicates the dilution factor.


#### 2.2.4. Determination of Free Amino Acids

(1) Reagent Preparation. The reagents were processed as required, and the glutamate standard stock solution and the solution to be measured were prepared at the required concentrations.(2) Determination Procedure. λ=570nm, glutamate standard curve and sample to be measured, 3 replicates, and average value. The free amino acid content was calculated as shown in the following equation.
(4)Freeaminoacidcontent=C/1000×V2m×ω×100%,where C is the mass of glutamate corresponding to the measured absorbance A in mg, V1 is the total assay volume in mL, and V2 is the volume of assay liquid removed in mL.


#### 2.2.5. Determination of Tea Polysaccharides

Tea polysaccharide was determined using the phenol-sulphuric acid method, and tea polysaccharide was extracted using the ultrasonic alcoholic sedimentation method and detected at UV spectroscopy.(1) Standard Solution Preparation. 0.1 mg/mL of glucose standard solution was prepared.(2) Tea Polysaccharide Extraction. The standard curve was drawn by pipetting the prepared glucose standard stock solution into 7 stoppered cuvettes and fixing the volume to 1 mL. Select 487 nm as the detection wavelength.(3) Determination of Tea Polysaccharide. The sample was treated according to the required operation method to obtain the solution to be measured, and 1 mL of the solution to be measured was taken and detected at 487 nm according to the flow of the standard curve. The formula for calculating the tea polysaccharide content is shown in the following equation.
(5)Teapolysaccharidecontent%=m1×V1×0.9×10−4m2×V2×100%,wherem1 indicates the amount of glucose corresponding to the measured absorbance in μg, V1 is the volume of the assay solution after volume determination in mL, V2 indicates the volume of the assay solution removed in mL, and m2 is the weight of the sample weighed in g. The functional analytical route for these five assays is shown in Figure 2.Figure 2
Technical route for functional analysis of tea leaves.


## 2.1. Materials and Equipment

### 2.1.1. Experimental Materials and Main Reagents

Materials are Mao Jian tea from the Lvliang Mountains, Pu’er tea (from Yunnan), black tea (from Anhui), and green tea (from Jiangsu) that were all purchased from local supermarkets.Reagents are sodium nitrite, aluminium nitrate, sodium hydroxide, rutin standard, anhydrous ethanol, distilled water, basic lead acetate, concentrated hydrochloric acid solution, concentrated sulphuric acid solution, caffeine standard, methanol, sodium carbonate, forinol reagent, gallic acid standard, glutamic acid standard, disodium hydrogen phosphate dodecahydrate, potassium dihydrogen phosphate, hydrated ninhydrin, stannous chloride, glucose, and phenol.


### 2.1.2. Apparatus and Equipment

Apparatus and equipment are BSA224S analytical balance, UV-1600 UV-Visible spectrophotometer, HK-02A 100 g hand-held grinder, UPT-I-10 T ultrapure water apparatus, DZKW-D-2 electric thermostatic water bath, 101-2AB electric blast drying oven, KQ-300DE ultrasonic instrument, and SC-3610 low-speed centrifuge.


## 2.1.1. Experimental Materials and Main Reagents

Materials are Mao Jian tea from the Lvliang Mountains, Pu’er tea (from Yunnan), black tea (from Anhui), and green tea (from Jiangsu) that were all purchased from local supermarkets.Reagents are sodium nitrite, aluminium nitrate, sodium hydroxide, rutin standard, anhydrous ethanol, distilled water, basic lead acetate, concentrated hydrochloric acid solution, concentrated sulphuric acid solution, caffeine standard, methanol, sodium carbonate, forinol reagent, gallic acid standard, glutamic acid standard, disodium hydrogen phosphate dodecahydrate, potassium dihydrogen phosphate, hydrated ninhydrin, stannous chloride, glucose, and phenol.


## 2.1.2. Apparatus and Equipment

Apparatus and equipment are BSA224S analytical balance, UV-1600 UV-Visible spectrophotometer, HK-02A 100 g hand-held grinder, UPT-I-10 T ultrapure water apparatus, DZKW-D-2 electric thermostatic water bath, 101-2AB electric blast drying oven, KQ-300DE ultrasonic instrument, and SC-3610 low-speed centrifuge.


## 2.2. Experimental Methods

### 2.2.1. Determination of Flavonoids

(1) Sample Processing. Dry the crushed 40-mesh sieved Lvliang Mountain Mao Jian tea and other specialty teas to a constant weight. Weigh 1 g of powdered Lvliang Mao Jian tea and other specialty teas in a conical flask, add ethanol at a volume of 1 : 60 of tea mass: 80% (V/V) ethanol solution, and sonicate for 25 min and then filter to obtain the solution to be measured.(2) Standard Curve Plotting. To analyze the effect of different times on the curve plotting, we first pipetted 10 mL of the rutin control solution and added the reactant to this solution as required. After preparation, the reaction was allowed to stand for 6 min, 6 min, and 20 min after each colour development step. 510 nm was chosen as the detection wavelength for all three experiments.(3) Determination of the Sample. 0.5 mL of the solution to be measured was transferred into a 25 mL cuvette, the solution was added according to the required addition procedure and mixed well to obtain the colour development solution, and λ=510nm was selected as the detection wavelength. The formula for calculating the flavonoid content was as follows.
(1)Flavonoidcontentmg/g=C×V1×V2/V3m,where C is the corresponding amount of rutin calculated from the measured absorbance A in mg/mL. V1 is the volume before the addition of the reactant in mL. V2 is the total volume in mL. V3 represents the volume of the assay liquid removed in mL. m represents the mass of the tea powder sample weighed in g.


### 2.2.2. Determination of Caffeine

The process consists of two main parts. (1) Preparation of reagents. The standard solution of lead acetate, concentrated hydrochloric acid, and concentrated sulphuric acid was prepared according to the standard; and the standard solution of caffeine and the solution to be measured were prepared, respectively. (2) Determination procedure. A standard curve of caffeine was prepared, and the sample to be tested was measured. Equation (2) is the calculation method for caffeine content.
(2)Caffeinecontent=C2×V2/1000×25m×ω×100%,where C2 is the concentration of caffeine corresponding to the measured absorbance A in mg/mL. V2 is the volume of the test liquid removed in mL. m indicates the amount of sample in grams g. ω is the dry matter content of the tea sample weighed in %.


### 2.2.3. Determination of Tea Polyphenols

(1) Reagent Preparation. Florinol, methanol, and sodium carbonate were prepared to the required concentrations and labelled as required, and then, the gallic acid standard stock solution and the solution to be measured were prepared according to the experimental needs.(2) Determination Steps. λ=765nm, standard curve of gallic acid and sample to be measured, and 3 replicate experiments to take the average value. The formula for the calculation of tea polyphenol content is shown in the following equation.
(3)CTP=A−A0×V×d×100SLOPEStd×ω×106×m,whereCTP indicates the tea polyphenol content, A is the absorbance of the sample test solution, A0 is the absorbance of the reagent blank, SLOPEStd indicates the slope of the standard curve, m is the sample mass in g, V is the total amount of mother liquor in mL, and d indicates the dilution factor.


### 2.2.4. Determination of Free Amino Acids

(1) Reagent Preparation. The reagents were processed as required, and the glutamate standard stock solution and the solution to be measured were prepared at the required concentrations.(2) Determination Procedure. λ=570nm, glutamate standard curve and sample to be measured, 3 replicates, and average value. The free amino acid content was calculated as shown in the following equation.
(4)Freeaminoacidcontent=C/1000×V2m×ω×100%,where C is the mass of glutamate corresponding to the measured absorbance A in mg, V1 is the total assay volume in mL, and V2 is the volume of assay liquid removed in mL.


### 2.2.5. Determination of Tea Polysaccharides

Tea polysaccharide was determined using the phenol-sulphuric acid method, and tea polysaccharide was extracted using the ultrasonic alcoholic sedimentation method and detected at UV spectroscopy.(1) Standard Solution Preparation. 0.1 mg/mL of glucose standard solution was prepared.(2) Tea Polysaccharide Extraction. The standard curve was drawn by pipetting the prepared glucose standard stock solution into 7 stoppered cuvettes and fixing the volume to 1 mL. Select 487 nm as the detection wavelength.(3) Determination of Tea Polysaccharide. The sample was treated according to the required operation method to obtain the solution to be measured, and 1 mL of the solution to be measured was taken and detected at 487 nm according to the flow of the standard curve. The formula for calculating the tea polysaccharide content is shown in the following equation.
(5)Teapolysaccharidecontent%=m1×V1×0.9×10−4m2×V2×100%,wherem1 indicates the amount of glucose corresponding to the measured absorbance in μg, V1 is the volume of the assay solution after volume determination in mL, V2 indicates the volume of the assay solution removed in mL, and m2 is the weight of the sample weighed in g. The functional analytical route for these five assays is shown in Figure 2.Figure 2
Technical route for functional analysis of tea leaves.


## 2.2.1. Determination of Flavonoids

(1) Sample Processing. Dry the crushed 40-mesh sieved Lvliang Mountain Mao Jian tea and other specialty teas to a constant weight. Weigh 1 g of powdered Lvliang Mao Jian tea and other specialty teas in a conical flask, add ethanol at a volume of 1 : 60 of tea mass: 80% (V/V) ethanol solution, and sonicate for 25 min and then filter to obtain the solution to be measured.(2) Standard Curve Plotting. To analyze the effect of different times on the curve plotting, we first pipetted 10 mL of the rutin control solution and added the reactant to this solution as required. After preparation, the reaction was allowed to stand for 6 min, 6 min, and 20 min after each colour development step. 510 nm was chosen as the detection wavelength for all three experiments.(3) Determination of the Sample. 0.5 mL of the solution to be measured was transferred into a 25 mL cuvette, the solution was added according to the required addition procedure and mixed well to obtain the colour development solution, and λ=510nm was selected as the detection wavelength. The formula for calculating the flavonoid content was as follows.
(1)Flavonoidcontentmg/g=C×V1×V2/V3m,where C is the corresponding amount of rutin calculated from the measured absorbance A in mg/mL. V1 is the volume before the addition of the reactant in mL. V2 is the total volume in mL. V3 represents the volume of the assay liquid removed in mL. m represents the mass of the tea powder sample weighed in g.


## 2.2.2. Determination of Caffeine

The process consists of two main parts. (1) Preparation of reagents. The standard solution of lead acetate, concentrated hydrochloric acid, and concentrated sulphuric acid was prepared according to the standard; and the standard solution of caffeine and the solution to be measured were prepared, respectively. (2) Determination procedure. A standard curve of caffeine was prepared, and the sample to be tested was measured. Equation (2) is the calculation method for caffeine content.
(2)Caffeinecontent=C2×V2/1000×25m×ω×100%,where C2 is the concentration of caffeine corresponding to the measured absorbance A in mg/mL. V2 is the volume of the test liquid removed in mL. m indicates the amount of sample in grams g. ω is the dry matter content of the tea sample weighed in %.


## 2.2.3. Determination of Tea Polyphenols

(1) Reagent Preparation. Florinol, methanol, and sodium carbonate were prepared to the required concentrations and labelled as required, and then, the gallic acid standard stock solution and the solution to be measured were prepared according to the experimental needs.(2) Determination Steps. λ=765nm, standard curve of gallic acid and sample to be measured, and 3 replicate experiments to take the average value. The formula for the calculation of tea polyphenol content is shown in the following equation.
(3)CTP=A−A0×V×d×100SLOPEStd×ω×106×m,whereCTP indicates the tea polyphenol content, A is the absorbance of the sample test solution, A0 is the absorbance of the reagent blank, SLOPEStd indicates the slope of the standard curve, m is the sample mass in g, V is the total amount of mother liquor in mL, and d indicates the dilution factor.


## 2.2.4. Determination of Free Amino Acids

(1) Reagent Preparation. The reagents were processed as required, and the glutamate standard stock solution and the solution to be measured were prepared at the required concentrations.(2) Determination Procedure. λ=570nm, glutamate standard curve and sample to be measured, 3 replicates, and average value. The free amino acid content was calculated as shown in the following equation.
(4)Freeaminoacidcontent=C/1000×V2m×ω×100%,where C is the mass of glutamate corresponding to the measured absorbance A in mg, V1 is the total assay volume in mL, and V2 is the volume of assay liquid removed in mL.


## 2.2.5. Determination of Tea Polysaccharides

Tea polysaccharide was determined using the phenol-sulphuric acid method, and tea polysaccharide was extracted using the ultrasonic alcoholic sedimentation method and detected at UV spectroscopy.(1) Standard Solution Preparation. 0.1 mg/mL of glucose standard solution was prepared.(2) Tea Polysaccharide Extraction. The standard curve was drawn by pipetting the prepared glucose standard stock solution into 7 stoppered cuvettes and fixing the volume to 1 mL. Select 487 nm as the detection wavelength.(3) Determination of Tea Polysaccharide. The sample was treated according to the required operation method to obtain the solution to be measured, and 1 mL of the solution to be measured was taken and detected at 487 nm according to the flow of the standard curve. The formula for calculating the tea polysaccharide content is shown in the following equation.
(5)Teapolysaccharidecontent%=m1×V1×0.9×10−4m2×V2×100%,wherem1 indicates the amount of glucose corresponding to the measured absorbance in μg, V1 is the volume of the assay solution after volume determination in mL, V2 indicates the volume of the assay solution removed in mL, and m2 is the weight of the sample weighed in g. The functional analytical route for these five assays is shown in Figure 2.Figure 2
Technical route for functional analysis of tea leaves.


## 3. Functional Analysis of Tea Leaves

### 3.1. Determination of Functional Components of Different Tea Leaves

The functional components such as flavonoids, caffeine, tea polyphenols, free amino acids, and tea polysaccharides were measured by UV spectrophotometric method, and the standard curve equations and linear ranges of these functional components were obtained by selecting different standards at different wavelengths as shown in Table1.Table 1
Standard curve equations.
NameCurve equationR2Linear rangeFlavonoidsY=8.89X−0.0030.9950-0.07mg/mLCaffeineY=51.37X−0.0020.9970-0.012mg/mLTea polyphenolsY=0.01X+0.0510.9930-90μg/mLFree amino acidsY=3.57X−0.1650.9900-0.8mg/mLTea polysaccharidesY=91.41X+0.0050.9990-0.009mg/mLIt can be seen from Table1 that the different standards have good linearity in the corresponding ranges and can be used as standard reference curves. The results of the determination of the functional components of Mao Jian tea and other specialty teas in the Luliang Mountains are shown in Table 2.Table 2
Results of the content assay.
NameMao Jian chaPu’er teaBlack teaGreen teaFlavonoids23.2329.6535.6839.54Caffeine3.495.898.217.41Tea polyphenols8.7511.2512.2515.24Free amino acids4.255.214.586.68Tea polysaccharides6.687.456.255.68Moisture10.468.696.6810.26A visual comparison of the results of the four teas’ content tests is shown in Figure3.Figure 3
Visual comparison of the results of the four tea varieties.From Figure3, it can be seen that all teas contain functional components such as flavonoids, caffeine, tea polyphenols, free amino acids, and tea polysaccharides; and the content of each functional component varies among tea varieties, which may be related to the different raw materials and production processes of various teas.


### 3.2. Comparative Analysis of Flavonoids

The results of the comparison of total flavonoids between Mao Jian tea and other teas in Lvliang Mountains are shown in Figure4(a); it can be seen that Mao Jian tea, Pu’er tea, black tea, and green tea in Lvliang Mountains all contain high content of flavonoids, among which the highest content of flavonoids was found in green tea, reaching 186.565 mg/g, followed by black tea and Pu’er tea, with 148.962 mg/g and 120.643 mg/g, respectively. The flavonoid content of Mao Jian tea from the Lvliang Mountains was significantly lower than that of the other three types of tea, at 73.233 mg/g. The raw material of Mao Jian tea, Mao Jian grass from the Lvliang Mountains, was rich in flavonoids, but its content was seriously lost after being made into Mao Jian tea, probably due to the oxidation of flavonoids caused by the high temperature and humidity during the processing of Mao Jian tea from the Lvliang Mountains. Therefore, the total flavonoid content of Lvliang Mao Jian tea is relatively low and, therefore, needs to be improved in the future processing process.Figure 4
Comparison of the total flavonoid and caffeine contents of the four teas.
(a)
Flavonoids(b)
Caffeine


### 3.3. Comparative Analysis of Caffeine

The results of the comparison of the caffeine content of Lvliang Mao Jian tea and other teas are shown in Figure4(b). The highest caffeine content among the four teas compared was 4.358% in black tea, in the middle was 3.374% and 2.894% in green tea and pu-erh tea, respectively, while the lowest caffeine content was 0.495% in Lvliang Mountain Mao Jian tea, which is the reason why the tea broth of Lvliang Mountain Mao Jian tea is not very bitter. Due to the special characteristics of tea, drinking it before bedtime often causes insomnia, but unlike other special teas, drinking it before bedtime not only does not cause insomnia but also has a calming effect on the mind, which helps you sleep and ensures a normal sleep. Because of its low caffeine content, it has a less stimulating effect on the stomach and is therefore suitable for all people, including the elderly and children.


### 3.4. Comparative Analysis of Tea Polyphenols

The content of tea polyphenols in pu-erh tea, black tea, and green tea were all relatively high. Green tea has the highest polyphenol content of 23.937%, while the content of tea polyphenols in pu-erh tea and black tea is 13.530% and 15.739%, respectively, and the content of tea polyphenols in Mao Jian tea of Lvliang mountain range is relatively low at 4.759%, which is only one-sixth of the content of green tea. It is well known that the amount of polyphenolic content has an important relationship with the tenderness of the tea leaves at the time of harvesting, the lower the maturity of the tea leaves the higher the polyphenolic content, so Mao Jian Cao grows relatively slowly compared to other specialty teas, which results in the lower polyphenolic content of Mao Jian tea in the Luliang Mountains compared to other teas.Catechins are the highest proportion of polyphenols in tea, so it can be assumed that the catechin content in Lvliang Mao Jian tea is also lower. This may be related to the processing of Lvliang Mao Jian tea, first, the degradation of polyphenols during processing and the fermentation process, so the catechin substance is oxidized and degraded during the fermentation process, resulting in less catechin substance. Second, as a fermented tea, the yellow and red pigment substances that cause the red colour of the tea broth of Lvliang Mountain Mao Jian tea during the fermentation process are formed by the polymerization of catechins under the action of enzymes, which makes the content of catechins lower.


### 3.5. Comparative Analysis of Free Amino Acids

The results of the comparison of free amino acid content and tea polyphenol content between Mao Jian tea and other teas in the Luliang Mountains are shown in Figure5. In comparison, the free amino acid content of green tea was the highest, up to 3.678%; the difference between the free amino acid content of Lvliang Mao Jian tea, Pu’er tea, and black tea was not significant; and the difference from high to low was 1.459% for black tea, 1.200% for Lvliang Mao Jian tea, and 1.185% for Pu’er tea. Therefore, the free amino acid content of Lvliang Mountain Mao Jian tea is also considerable. The content of free amino acid is directly related to the metabolism of nitrogenous compounds in the tea body, such as transformation and decomposition. The harvesting of Lvliang Mountain Mao Jian tea takes place in summer, and the higher temperature causes some of the proteins to decompose into free amino acids.Figure 5
Comparison of free amino acid content and tea polyphenol content of the four teas.The high level of free amino acids and other nutrients in Lvliang Mao Jian tea can help the synthesis of acid in the stomach, leading to an increase in the secretion of gastric juices, thus helping to improve the function of the stomach and intestines, aiding digestion, improving appetite, and having a preventive and therapeutic effect on enteritis and gastritis. Theanine is the main component of free amino acids, so the content of theanine increases with the free amino acid content, resulting in a considerable theanine content in Lvliang Mountain Mao Jian tea, so Lvliang Mountain Mao Jian tea can, to a certain extent, resist fatigue, lower blood pressure, and can improve memory.


### 3.6. Comparative Analysis of Tea Polysaccharides

The results of comparing the tea polysaccharide contents of Lvliang Mao Jian tea and other teas are shown in Figure6(a). It can be seen that the tea polysaccharide contents of Lvliang Mao Jian tea, Pu’er tea, black tea and green tea were all relatively high, among which black tea was the most abundant at 3.784%, followed by Lvliang Mao Jian tea at 3.656%, and the tea polysaccharide contents of Pu’er tea and green tea were 3.472% and 2.663%, respectively, so the tea polysaccharide content of Mao Jian tea in the Luliang Mountains was relatively high.Figure 6
Comparison of tea polysaccharide content and moisture content of the four teas.
(a)
Flavonoids(b)
CaffeineThe reasons for this may be related to two things: first, the amount of polysaccharide accumulation is highly related to the natural conditions in which it grows. Second, it is related to the processing process, after a series of kneading and fermentation process, it will lead to the acidic environment of Lvliang Mao Jian tea, under this acidic condition, the soluble pectin and calcium ions will form irreversible precipitation complex, which will cause a certain degree of loss of tea polysaccharide and eventually lead to the content of tea polysaccharide in Lvliang Mao Jian tea is not the highest. Although tea polysaccharide is a “sugar,” it can reduce blood lipid and blood sugar levels to a certain extent, so Lvliang Mao Jian tea is friendly to people with three highs. Tea polysaccharides can also scavenge free radicals to a certain extent.


### 3.7. Comparative Analysis of Water Content

The water content of Lvliang Mao Jian tea and other teas is compared in Figure6(b). The moisture content of Mao Jian tea from the Lvliang Mountains was found to be 10.466%, which is the highest among the four teas. The moisture content of green tea and pu-erh tea was 7.785% and 7.370%, respectively. Black tea has the lowest moisture content, mostly because for water-soluble nutrients, and black tea is the least conducive to nutrient storage, while the quality of Lvliang Mountain Mao Jian tea can be guaranteed.


## 3.1. Determination of Functional Components of Different Tea Leaves

The functional components such as flavonoids, caffeine, tea polyphenols, free amino acids, and tea polysaccharides were measured by UV spectrophotometric method, and the standard curve equations and linear ranges of these functional components were obtained by selecting different standards at different wavelengths as shown in Table1.Table 1
Standard curve equations.
NameCurve equationR2Linear rangeFlavonoidsY=8.89X−0.0030.9950-0.07mg/mLCaffeineY=51.37X−0.0020.9970-0.012mg/mLTea polyphenolsY=0.01X+0.0510.9930-90μg/mLFree amino acidsY=3.57X−0.1650.9900-0.8mg/mLTea polysaccharidesY=91.41X+0.0050.9990-0.009mg/mLIt can be seen from Table1 that the different standards have good linearity in the corresponding ranges and can be used as standard reference curves. The results of the determination of the functional components of Mao Jian tea and other specialty teas in the Luliang Mountains are shown in Table 2.Table 2
Results of the content assay.
NameMao Jian chaPu’er teaBlack teaGreen teaFlavonoids23.2329.6535.6839.54Caffeine3.495.898.217.41Tea polyphenols8.7511.2512.2515.24Free amino acids4.255.214.586.68Tea polysaccharides6.687.456.255.68Moisture10.468.696.6810.26A visual comparison of the results of the four teas’ content tests is shown in Figure3.Figure 3
Visual comparison of the results of the four tea varieties.From Figure3, it can be seen that all teas contain functional components such as flavonoids, caffeine, tea polyphenols, free amino acids, and tea polysaccharides; and the content of each functional component varies among tea varieties, which may be related to the different raw materials and production processes of various teas.


## 3.2. Comparative Analysis of Flavonoids

The results of the comparison of total flavonoids between Mao Jian tea and other teas in Lvliang Mountains are shown in Figure4(a); it can be seen that Mao Jian tea, Pu’er tea, black tea, and green tea in Lvliang Mountains all contain high content of flavonoids, among which the highest content of flavonoids was found in green tea, reaching 186.565 mg/g, followed by black tea and Pu’er tea, with 148.962 mg/g and 120.643 mg/g, respectively. The flavonoid content of Mao Jian tea from the Lvliang Mountains was significantly lower than that of the other three types of tea, at 73.233 mg/g. The raw material of Mao Jian tea, Mao Jian grass from the Lvliang Mountains, was rich in flavonoids, but its content was seriously lost after being made into Mao Jian tea, probably due to the oxidation of flavonoids caused by the high temperature and humidity during the processing of Mao Jian tea from the Lvliang Mountains. Therefore, the total flavonoid content of Lvliang Mao Jian tea is relatively low and, therefore, needs to be improved in the future processing process.Figure 4
Comparison of the total flavonoid and caffeine contents of the four teas.
(a)
Flavonoids(b)
Caffeine


## 3.3. Comparative Analysis of Caffeine

The results of the comparison of the caffeine content of Lvliang Mao Jian tea and other teas are shown in Figure4(b). The highest caffeine content among the four teas compared was 4.358% in black tea, in the middle was 3.374% and 2.894% in green tea and pu-erh tea, respectively, while the lowest caffeine content was 0.495% in Lvliang Mountain Mao Jian tea, which is the reason why the tea broth of Lvliang Mountain Mao Jian tea is not very bitter. Due to the special characteristics of tea, drinking it before bedtime often causes insomnia, but unlike other special teas, drinking it before bedtime not only does not cause insomnia but also has a calming effect on the mind, which helps you sleep and ensures a normal sleep. Because of its low caffeine content, it has a less stimulating effect on the stomach and is therefore suitable for all people, including the elderly and children.


## 3.4. Comparative Analysis of Tea Polyphenols

The content of tea polyphenols in pu-erh tea, black tea, and green tea were all relatively high. Green tea has the highest polyphenol content of 23.937%, while the content of tea polyphenols in pu-erh tea and black tea is 13.530% and 15.739%, respectively, and the content of tea polyphenols in Mao Jian tea of Lvliang mountain range is relatively low at 4.759%, which is only one-sixth of the content of green tea. It is well known that the amount of polyphenolic content has an important relationship with the tenderness of the tea leaves at the time of harvesting, the lower the maturity of the tea leaves the higher the polyphenolic content, so Mao Jian Cao grows relatively slowly compared to other specialty teas, which results in the lower polyphenolic content of Mao Jian tea in the Luliang Mountains compared to other teas.Catechins are the highest proportion of polyphenols in tea, so it can be assumed that the catechin content in Lvliang Mao Jian tea is also lower. This may be related to the processing of Lvliang Mao Jian tea, first, the degradation of polyphenols during processing and the fermentation process, so the catechin substance is oxidized and degraded during the fermentation process, resulting in less catechin substance. Second, as a fermented tea, the yellow and red pigment substances that cause the red colour of the tea broth of Lvliang Mountain Mao Jian tea during the fermentation process are formed by the polymerization of catechins under the action of enzymes, which makes the content of catechins lower.


## 3.5. Comparative Analysis of Free Amino Acids

The results of the comparison of free amino acid content and tea polyphenol content between Mao Jian tea and other teas in the Luliang Mountains are shown in Figure5. In comparison, the free amino acid content of green tea was the highest, up to 3.678%; the difference between the free amino acid content of Lvliang Mao Jian tea, Pu’er tea, and black tea was not significant; and the difference from high to low was 1.459% for black tea, 1.200% for Lvliang Mao Jian tea, and 1.185% for Pu’er tea. Therefore, the free amino acid content of Lvliang Mountain Mao Jian tea is also considerable. The content of free amino acid is directly related to the metabolism of nitrogenous compounds in the tea body, such as transformation and decomposition. The harvesting of Lvliang Mountain Mao Jian tea takes place in summer, and the higher temperature causes some of the proteins to decompose into free amino acids.Figure 5
Comparison of free amino acid content and tea polyphenol content of the four teas.The high level of free amino acids and other nutrients in Lvliang Mao Jian tea can help the synthesis of acid in the stomach, leading to an increase in the secretion of gastric juices, thus helping to improve the function of the stomach and intestines, aiding digestion, improving appetite, and having a preventive and therapeutic effect on enteritis and gastritis. Theanine is the main component of free amino acids, so the content of theanine increases with the free amino acid content, resulting in a considerable theanine content in Lvliang Mountain Mao Jian tea, so Lvliang Mountain Mao Jian tea can, to a certain extent, resist fatigue, lower blood pressure, and can improve memory.


## 3.6. Comparative Analysis of Tea Polysaccharides

The results of comparing the tea polysaccharide contents of Lvliang Mao Jian tea and other teas are shown in Figure6(a). It can be seen that the tea polysaccharide contents of Lvliang Mao Jian tea, Pu’er tea, black tea and green tea were all relatively high, among which black tea was the most abundant at 3.784%, followed by Lvliang Mao Jian tea at 3.656%, and the tea polysaccharide contents of Pu’er tea and green tea were 3.472% and 2.663%, respectively, so the tea polysaccharide content of Mao Jian tea in the Luliang Mountains was relatively high.Figure 6
Comparison of tea polysaccharide content and moisture content of the four teas.
(a)
Flavonoids(b)
CaffeineThe reasons for this may be related to two things: first, the amount of polysaccharide accumulation is highly related to the natural conditions in which it grows. Second, it is related to the processing process, after a series of kneading and fermentation process, it will lead to the acidic environment of Lvliang Mao Jian tea, under this acidic condition, the soluble pectin and calcium ions will form irreversible precipitation complex, which will cause a certain degree of loss of tea polysaccharide and eventually lead to the content of tea polysaccharide in Lvliang Mao Jian tea is not the highest. Although tea polysaccharide is a “sugar,” it can reduce blood lipid and blood sugar levels to a certain extent, so Lvliang Mao Jian tea is friendly to people with three highs. Tea polysaccharides can also scavenge free radicals to a certain extent.


## 3.7. Comparative Analysis of Water Content

The water content of Lvliang Mao Jian tea and other teas is compared in Figure6(b). The moisture content of Mao Jian tea from the Lvliang Mountains was found to be 10.466%, which is the highest among the four teas. The moisture content of green tea and pu-erh tea was 7.785% and 7.370%, respectively. Black tea has the lowest moisture content, mostly because for water-soluble nutrients, and black tea is the least conducive to nutrient storage, while the quality of Lvliang Mountain Mao Jian tea can be guaranteed.


## 4. Experimental Method

With the emergence of the phenomenon of subhealth, the concept of health care is gradually gaining attention. As an important beverage essential to people’s daily health care, the rationality of the brewing method directly affects the functionality of the functional substances in tea. In order to make the flavonoid content of Lvliang Mao Jian tea as soluble as possible, so that the efficacy of flavonoids can be played out to the greatest extent possible and be better absorbed and utilized by the human body, the tea was brewed in a way that has a direct impact on the functional properties of the tea. In order to make the flavonoid content of Lvliang Mao Jian tea as soluble as possible and to maximize the efficacy of the flavonoids, which can be better absorbed and utilized by the human body, it is necessary to optimize the optimal brewing conditions for Lvliang Mao Jian tea. The three factors of brewing temperature, tea-water ratio, and brewing time were selected for the experimental study of biological activity to find the best scientific brewing conditions.A 1 g sample of Lvliang Mao Jian tea was weighed into a beaker and brewed at different brewing temperatures, times, and tea-water ratios according to the experimental conditions. The tea broth filtrate was then filtered and used for the determination of flavonoids in the tea broth.Experiment 1: 7 equal portions of 1 g of Lvliang Mao Jian tea were weighed into a beaker and added to a barrel of drinking water at 100°C for 10 min in the ratio of 1 : 20, 1 : 40, 1 : 60, 1 : 80, 1 : 100, 1 : 120, and 1 : 140 by mass volume of Lvliang Mao Jian tea to water. The filtrate was then filtered and used for the determination of flavonoids in the tea broth.Experiment 2: 7 equal portions of 1 g of Lvliang Mao Jian tea were weighed into a beaker, 100 ml of drinking water was added at 100°C, brewed for 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, and 35 min, and then filtered to obtain the filtrate for the determination of flavonoid content.After analyzing the results of the completed single-factor experiments, three objective levels were selected for orthogonal optimization to determine the best brewing conditions, and the experimental factor levels are shown in Table3.Table 3
Table of experimental factor levels.
LevelBrewing water temperatureTea to water ratioBrewing time180804029010060310012070The comparison of the experimental factor levels is shown in Figure7.Figure 7
Comparison of the levels of the experimental factors.The overall effect of brewing water temperature on the brewing conditions of Mao Jian tea from the Lvliang Mountains showed an increasing trend, reaching a maximum at 100°C, when the amount of flavonoids dissolved in the tea broth reached 33.67 mg/g. This may be due to some changes in the cellular structure caused by the increase in temperature. The data on the effect of tea water ratio and brewing time on the brewing conditions are shown in Tables4 and 5.Table 4
Effect of tea ratio on brewing conditions.
Volume (mL)Content (mg/g)2016401860238027100331202614025Table 5
Influence of brewing time on brewing conditions.
Time (min)Content (mg/g)627103116322043254230413542A comparison of the data on the effect of tea ratio and brewing time on brewing conditions is shown in Figure8.Figure 8
Comparison of the effects of tea-water ratio and brewing time on brewing conditions.
(a)
Volume (mL)(b)
Time (min)From Figure8(a), it can be seen that the influence of tea-water ratio on the brewing conditions of Lvliang Mao Jian tea showed a trend of increasing and then decreasing, reaching the maximum at the tea-water ratio of 1 : 100, when the flavonoid content in the tea broth could reach 33.90 mg/g.As can be seen from Figure8(b), the overall effect of brewing time on the brewing conditions of Mao Jian tea in the Lvliang Mountains showed a trend of increasing from 5 to 20 min and then reaching a stable state at a high level after 20 min. Between 5 min and 20 min, the amount of flavonoids leached increased with the increase of brewing time, but the leaching rate of flavonoids was slower in the early stage and faster in the later stage. At 20 min, the amount of flavonoids reaches a certain level and is in a stable state, so that no more flavonoids are leached out.It was found that when the tea leaves were brewed for a short period of time, Lvliang Mao Jian tea was not able to spread out, which caused the flavonoids to be unable to be fully dissolved. When the dissolution rate was low, it was found that the tea leaves were fully expanded after 20 min to maximize the dissolution of flavonoids, and the biological activity was optimal at this time.In conclusion, the ratio of tea to water had a significant effect on the brewing of Lvliang Mao Jian tea, while the brewing temperature and time did not have a significant effect on the brewing of Lvliang Mao Jian tea. The average value of 43.29 mg/g was obtained from the three validation experiments, and the dissolved amount in the validation experiment was higher than the other dissolved amounts in the orthogonal table. Therefore, the brewing temperature of 90°C, the brewing time of 20 min, and the ratio of tea to water of 1 : 120 were determined to be the best brewing conditions for Mao Jian tea in the Lvliang Mountains, which are highly feasible and reliable.


## 5. Conclusion

Tea production is a long-established production field, and the study of functional components and biological activities of tea is an important research direction. With the rapid development of the technological and economic aspects of the Internet, the traditional methods of functional tea research have been unable to meet the growing demand, and a change of mindset is necessary to learn the latest methods of bioactivity research. In this paper, the content of functional components such as flavonoids, caffeine, tea polyphenols, free amino acids, tea polysaccharides, and water in Mao Jian tea of the Luliang Mountains, Pu’er tea, black tea, and green tea were compared and analyzed using UV spectrophotometric methods, and the differences in functional components between tea varieties were compared. The brewing conditions of Mao Jian tea in the Lvliang Mountains were optimized to analyze the effects of tea-water ratio, brewing temperature, and brewing time on the biological activity of Mao Jian tea in the Lvliang Mountains. The results showed that the brewing temperature of 90°C, the brewing time of 20 min, and the ratio of tea to water of 1 : 120 were the best brewing conditions for Mao Jian tea from Lvliang Mountains.



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*Source: 5207741-2022-09-24.xml*