CN111406566B

CN111406566B - Planting method for reducing content of caffeine in tea

Info

Publication number: CN111406566B
Application number: CN202010205739.1A
Authority: CN
Inventors: 薛岚; 雷莹; 庄凰龙
Original assignee: Ningde Normal University
Current assignee: Ningde Normal University
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2022-03-08
Anticipated expiration: 2040-03-23
Also published as: CN111406566A

Abstract

The invention provides a planting method for reducing the content of caffeine in tea, which comprises the following steps: s1, selecting a land with the soil pH value of 3.0-5.5, the growth temperature of 20-30 ℃ and the gradient of less than 30 ℃; s2, after the land is deeply ploughed for 100-150cm, detecting the contents of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus in the soil, and applying base fertilizer to adjust the soil so that the content of the alkaline hydrolysis nitrogen in the soil is lower than 30mg/kg, the content of the quick-acting potassium is 60-130mg/kg, and the content of the available phosphorus is 1.5-3.20 mg/kg; s3, planting tea seedlings without diseases and insect pests, wherein the plant spacing of the tea seedlings is 20-30cm, the row spacing is 100-150cm, and 2-3 tea seedlings are planted in each cluster for seedling protection and seedling supplement; and S4, managing the tea seedlings in the growth process, including applying Cd fertilizer, preventing and treating plant diseases and insect pests and trimming. The method can remarkably reduce the content of caffeine in tea, and has low cost.

Description

Planting method for reducing content of caffeine in tea

Technical Field

The invention relates to a planting method for reducing the content of caffeine in tea, and belongs to the technical field of tea tree planting.

Background

In China, tea culture has a long history, and in traditional life, tea is a necessity in the life of common people. A plurality of historical documents record the medicinal value of tea, and scientific researches at present further show that the tea drink not only can clear away summer heat and promote the production of body fluid to quench thirst, but also can dissolve fat, inhibit the rise of cholesterol and promote excretion because caffeine contained in the tea has the effects of sterilizing and diminishing inflammation, and can relax the vascular wall and reduce blood pressure, so that the tea drink is more popular in daily life. However, studies have shown that excessive caffeine (caffeine) intake has negative effects on human body, especially sensitive people, including people with metabolic disorders, liver disease patients, heart disease patients, neurasthenia, etc., which are more sensitive to caffeine intake than normal people and may be far less than the traditional lethal concentration, resulting in death. In addition, studies show that one-time intake of 10mg of caffeine can cause some uncomfortable symptoms, especially for sensitive people such as pregnant women and children. The tea is rich in caffeine and can be easily absorbed by human bodies, the absorption rate can reach 90%, and the human bodies can ingest higher caffeine by drinking tea, so that the intake of tea products is limited by sensitive people, therefore, the development of the low-caffeine tea has important significance, the requirements of the sensitive people on the tea can be met, the health-care beverage function of the tea can be achieved, and a larger tea consumption market is developed. At present, the method for reducing the caffeine in the tea leaves on the market mainly adopts the process to remove the caffeine in the tea leaves, so that the processing cost is increased, the quality of the removed tea leaves is reduced, chemical reagents can be remained in the tea leaves, and the risk is caused to the health of human bodies.

Disclosure of Invention

The invention provides a planting method for reducing the content of caffeine in tea, which can effectively solve the problems.

The invention is realized by the following steps:

a planting method for reducing the content of caffeine in tea leaves comprises the following steps:

s1, selecting a land with the growth temperature of 20-30 ℃ and the gradient of less than 30 ℃, and adjusting the pH value of the soil to 3.0-5.5 by using acid or alkali;

s2, after the land is deeply ploughed for 100-150cm, detecting the contents of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus in the soil, and applying base fertilizer to adjust the soil so that the content of the alkaline hydrolysis nitrogen in the soil is lower than 30mg/kg, the content of the quick-acting potassium is 60-130mg/kg, and the content of the available phosphorus is 1.5-3.20 mg/kg;

s3, planting tea seedlings without diseases and insect pests, wherein the plant spacing of the tea seedlings is 20-30cm, the row spacing is 100-150cm, and 2-3 tea seedlings are planted in each cluster for seedling protection and seedling supplement;

and S4, managing the tea seedlings in the growth process, including applying Cd fertilizer, preventing and treating plant diseases and insect pests and trimming.

As a further improvement, the quick-acting potassium is 100-130 mg/kg. Under the condition of the quick-acting potassium with relatively high concentration, the content of the caffeine in the tea trees can be reduced.

As a further improvement, the available phosphorus is 2.0-3.2 mg/kg. Under the condition of relatively high concentration of available phosphorus, the content of caffeine in tea trees can be reduced.

As a further improvement, the Cd fertilizer is uniformly applied every 2-3 months after planting, so that the Cd content in the soil is 0.1-0.3 mg/kg. The content of Cd in the soil is increased, and the content of caffeine in the soil can be reduced.

As a further improvement, the trimming is: when the tea seedlings are 30-40cm high, cutting off the new tips at the top ends of the main branches; when the tea seedlings are 50cm-60cm high, the upper branch tips are cut off, and the root necks and the downward and weak branches in the awning tree are cut off.

As a further improvement, the pest control is physical control or biological control, pesticides are not adopted, the pesticide is prevented from reducing the content of tea polyphenol in the tea, the quality of the tea is influenced, and the pesticide residue is reduced.

As a further improvement, the alkaline hydrolysis nitrogen in the soil is less than 30 mg/kg. If the alkaline hydrolysis nitrogen is higher than 30mg/kg, the content of the caffeine in the tea leaves is increased.

As a further improvement, the Cd fertilizer is a cadmium-reducing fertilizer.

As a further improvement, after the soil is deeply ploughed, the contents of As, Cr, Cu, Hg and Ni in the soil are detected, the content of As in the soil is ensured to be lower than 1.2mg/kg, the content of Cr is ensured to be lower than 36.8mg/kg, the content of Cu is ensured to be lower than 2.60mg/kg, the content of Hg is ensured to be lower than 0.012mg/kg, and the content of Ni is ensured to be lower than 9.50mg/kg, and if the conditions are not met, a new soil is replaced. Too high contents of As, Cr, Cu, Hg and Ni in the soil increase the content of caffeine in the tea leaves, and affect the quality of the tea leaves.

As a further improvement, the pH of the soil is 3.0-4.0. Within this pH range, it is advantageous to reduce the caffeine content in tea leaves, if the pH is lower than 3.0, the soil acidity is too strong to be conducive to the growth of tea trees, and if the pH is higher than 4.0, the caffeine content in tea leaves is significantly increased.

The invention has the beneficial effects that:

by applying a potassium fertilizer, a phosphate fertilizer and a Cd fertilizer, the content of Cd, available phosphorus and quick-acting potassium in soil is increased, the acidity of the soil is increased, and the content of caffeine in tea leaves is greatly reduced. Compared with the method for producing the low-caffeine tea leaves by adopting the process at the later stage, the method has the advantages that the safety is guaranteed, and the cost is reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Figure 1 is a standard graph of caffeine provided by an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Example 1

A planting method for increasing the content of caffeine in tea leaves comprises the following steps:

s1, selecting a land with the growth temperature of 20-30 ℃ and the gradient of less than 30 ℃, and adjusting the pH value of the soil to 5.11 by using acid or alkali, wherein the acid is a 1M hydrochloric acid solution, and the alkali is a 1M sodium hydroxide solution.

S2, after the land is deeply ploughed for 100-150cm, the contents of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus in the soil are measured, ditching is carried out, the ditch depth is 30-50cm, base fertilizer is applied in the ditch, the base fertilizer contains potassium chloride and calcium phosphate, the soil is uniformly mixed, and the contents of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus in the soil are adjusted to 31.32mg/kg, 22.41mg/kg and 0.39mg/kg respectively.

S3, planting tea seedlings without diseases and insect pests, wherein the plant spacing of the tea seedlings is 20-30cm, the row spacing is 100-150cm, and planting 2-3 tea seedlings in each cluster for seedling protection and seedling supplement.

The Cd fertilizer application is to uniformly apply Cd fertilizer every 2-3 months after planting, wherein the Cd fertilizer is cadmium reduction fertilizer, and the content of Cd in soil is 0.036 mg/kg. And simultaneously detecting the contents of As, Cr, Cu, Hg and Ni As 6.89, 75.00, 5.10, 0.012 and 14.80mg/kg respectively.

The method for detecting the contents of As, Cd, Cr, Cu, Hg and Ni in soil adopts inductively coupled plasma mass spectrometry (ICP-MS) to determine, has higher sensitivity, and compared with spectrophotometry, the method also has the characteristics of low detection limit, small interference and multi-element simultaneous determination.

The pruning is as follows: when the tea seedlings are 30-40cm high, cutting off the new tips at the top ends of the main branches; when the tea seedlings are 50cm-60cm high, the upper branch tips are cut off, and the root necks and the downward and weak branches in the awning tree are cut off.

The pest control is biological control, and concretely adopts a bacillus thuringiensis insecticide to kill pests.

The method for measuring the alkaline hydrolysis nitrogen in the soil comprises the following steps:

(1) weighing 1.00-2.00 g of air-dried soil sample which is sieved by a 2mm sieve, paving the air-dried soil sample in an outer chamber of a diffusion dish, adding 1g of zinc-ferrous sulfate reducing agent in the outer chamber of the soil, and paving the mixture on the soil;

(2) adding 3.0mL of 20g/L boric acid-indicator solution into the inner chamber of the diffusion dish;

(3) 10mL1.8mol/L sodium hydroxide solution is added into the gap outside a diffusion dish, and the diffusion dish is immediately covered by ground glass;

(4) titrating the ammonia amount absorbed in the boric acid in the inner chamber by using 0.1mol/L hydrochloric acid standard solution, and changing the color from blue to mauve to reach the end point;

(5) simultaneously carrying out reagent blank and standard soil sample measurement on the sample;

(6) and obtaining the content of the nitrogen element in the sample.

(7) Calculation of hydrolyzable Nitrogen content

In the formula: hydrolyzable nitrogen content in milligrams per kilogram (mg/kg); v titration of the sample with a standard solution volume of hydrochloric acid in milliliters (mL); v0 titration of the volume of hydrochloric acid standard solution used for the blank in milliliters (mL); c the concentration of the hydrochloric acid standard solution, wherein the unit is mol per liter (mol/L); m air-dried soil sample mass is gram (g); k1 the air dried sample is converted into the water conversion coefficient of the dried soil sample.

The method for measuring the quick-acting potassium in the soil comprises the following steps:

(1) weighing 5.00g of air-dried soil sample which passes through a sieve pore of 2mm and placing the air-dried soil sample into a leaching bottle;

(2) adding 50mL of 1mol/L ammonium acetate solution, adding a plug and then oscillating;

(3) filtering with filter paper, and directly measuring potassium in the filtrate with an inductively coupled plasma emission spectrometer;

(4) adjusting the zero point of an instrument by using a potassium solution of 0.00g/mL, and then determining a potassium standard series solution from low concentration to high concentration;

(5) the blank solution and the solution to be detected can be directly measured by an inductively coupled plasma emission spectrometer for potassium;

(6) the potassium concentrations of the blank solution and the test solution can be obtained directly from the instrument.

(7) Calculating the content of quick-acting potassium:

wherein WK1 rapid-acting potassium (K) content, (mg/kg); c, finding the concentration of potassium in the solution from the working curve, (mg/L); c, obtaining the potassium concentration (mg/L) in the blank solution from the working curve; v volume of leaching agent, 50 mL; m dried soil sample mass, g; k, converting the air-dried soil sample into a moisture conversion coefficient of the dried soil sample.

The method for measuring available phosphorus in soil comprises the following steps:

(1) selecting working parameters according to the instrument use instruction;

(2) standardizing the instrument by using a standard curve;

(3) inputting the weight and the volume of the soil sample, and using a blank solution as a reference;

(4) measuring the emission intensity of elements in a sample to be measured and a standard curve to directly calculate the content of phosphorus in the soil;

(5) obtaining the concentration of phosphorus element in the sample solution on the standard curve;

(6) calculation of available phosphorus

Wherein, WP available phosphorus content, (mg/L); converting the measurement signal of the X instrument into corresponding phosphorus content, (mg/kg); and k is converted into a moisture conversion coefficient of the dried soil sample from the air-dried soil sample.

When the tea is ripe, picking the tea for caffeine extraction and detection, wherein the detection method comprises the following steps:

(1) the caffeine standard solution with the concentration of 0.05g/L is prepared into standard solution to be detected with the concentration gradient of 0.002g/L, 0.004g/L, 0.006g/L, 0.008g/L, 0.01g/L and 0.012 g/L. Using an ultraviolet-visible spectrophotometer, a reference was made to the reagent blank solution at a wavelength of 274nm, the absorbance was measured, and a standard curve was drawn, as shown in FIG. 1.

(2) Weighing 1.5g (accurate to 0.0001g) of ground tea sample, preparing a test solution according to the national standard [8], after the preparation of the test solution is finished, using an ultraviolet visible spectrophotometer to perform reference at the wavelength of 274nm by using a reagent blank solution, measuring the absorbance of the test solution, and calculating the content of caffeine in the tea according to a standard curve.

The content of caffeine in tea leaves was measured to be 1.75 mg/L.

Example 2

The pH value of the soil is adjusted to 4.82 by acid or alkali, the base fertilizer contains potassium sulfate and calcium phosphate, and the content of alkaline hydrolysis nitrogen, the content of quick-acting potassium and the content of available phosphorus in the soil are controlled to be 34.1mg/kg, 97.53mg/kg and 3.19mg/kg respectively. And applying a Cd fertilizer which is a cadmium reduction fertilizer to ensure that the content of Cd in the soil is 0.185 mg/kg. The contents of As, Cr, Cu, Hg and Ni were measured to be 1.28, 36.80, 2.60, 0.015 and 9.50mg/kg, respectively, and the same As in example 1.

The content of caffeine in the tea leaves was measured to be 1.29 mg/L.

Example 3

The pH value of the soil is adjusted to 4.77 by acid or alkali, the base fertilizer is urea, plant ash and monoammonium phosphate, and the content of alkaline hydrolysis nitrogen, the content of quick-acting potassium and the content of available phosphorus in the soil are controlled to be 34.1mg/kg, 42.52mg/kg and 0.5mg/kg respectively. And applying a Cd fertilizer which is a cadmium reduction fertilizer to ensure that the content of Cd in the soil is 0.043 mg/kg. The contents of As, Cr, Cu, Hg and Ni were measured to be 4.94, 74.00, 6.40, 0.063 and 11.80mg/kg, respectively, and the same As example 1 was conducted.

The content of caffeine in the tea leaves was measured to be 1.82 mg/L.

Example 4

The pH value of the soil is adjusted to 5.23 by acid or alkali, the base fertilizer contains potassium epsom salt and diammonium phosphate, and the content of alkaline hydrolysis nitrogen, the content of quick-acting potassium and the content of available phosphorus in the soil are controlled to 47.33mg/kg, 30.5mg/kg and 1.96mg/kg respectively. And applying a Cd fertilizer which is a cadmium reduction fertilizer to ensure that the content of Cd in the soil is 0.091 mg/kg. The contents of As, Cr, Cu, Hg and Ni were measured to be 7.98, 99.00, 72.50, 0.081 and 15.70mg/kg, respectively, and the same As in example 1.

The content of caffeine in the tea leaves was measured to be 1.78 mg/L.

Example 5

The pH value of the soil is adjusted to 4.96 by acid or alkali, the base fertilizer contains monopotassium phosphate and calcium phosphate, and the content of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus in the soil are controlled to be 57.42mg/kg, 61.32mg/kg and 0.31mg/kg respectively. And applying a Cd fertilizer which is a cadmium reduction fertilizer to ensure that the content of Cd in the soil is 0.054 mg/kg. The same procedures As in example 1 were repeated except that the amounts of As, Cr, Cu, Hg and Ni were measured to be 10.87, 67.10, 29.40, 0.036 and 27.40mg/kg, respectively.

The content of caffeine in tea leaves was measured to be 1.77 mg/L.

Example 6

The pH value of the soil is adjusted to 4.21 by acid or alkali, the base fertilizer contains plant ash and monoammonium phosphate, and the content of alkaline hydrolysis nitrogen, the content of quick-acting potassium and the content of available phosphorus in the soil are controlled to be 76.56mg/kg, 38.52mg/kg and 0.79mg/kg respectively. And applying a Cd fertilizer which is a cadmium reduction fertilizer to ensure that the content of Cd in the soil is 0.023 mg/kg. The contents of As, Cr, Cu, Hg and Ni were measured to be 6.07, 83.70, 32.30, 0.086 and 23.20mg/kg, respectively, and the same As in example 1 was conducted.

The content of caffeine in tea leaves was measured to be 2.09 mg/L.

Example 7

The pH value of the soil is adjusted to 4.56 by acid or alkali, the base fertilizer contains potassium chloride and calcium phosphate, and the content of alkaline hydrolysis nitrogen, the content of quick-acting potassium and the content of available phosphorus in the soil are controlled to be 98.84mg/kg, 132.42mg/kg and 2.82mg/kg respectively. And applying a Cd fertilizer which is a cadmium reduction fertilizer to ensure that the content of Cd in the soil is 0.047 mg/kg. The contents of As, Cr, Cu, Hg and Ni were measured to be 7.20, 103.30, 20.30, 0.073 and 22.50mg/kg, respectively, and the same As in example 1.

The content of caffeine in tea leaves was measured to be 1.70 mg/L.

The correlation analysis of the soil of examples 1-7 for the quick-acting potassium, available phosphorus, pH, As, Cd, Cr, Cu, Hg, Ni and caffeine in tea leaves is shown in Table 1.

TABLE 1

TABLE 1 correlation of the content of each component in soil with the content of caffeine in tea

In 7 embodiments of the invention, the correlation between the content of each component in the soil and the content of caffeine in tea leaves is from high to low in order that the content of Cd is greater than the content of effective phosphorus, the content of Hg is greater than the content of Cr is greater than the content of Ni is greater than the content of As (quick-acting potassium), the content of Cu is greater than the content of pH is greater than the content of hydrolytic nitrogen, and experimental results show that the application of organic fertilizers rich in Cd, effective phosphorus and quick-acting potassium reduces the content of hydrolytic nitrogen, As, Cr, Cu, Hg and Ni in the soil, improves the acidity of the soil within a proper soil acidity range, and can greatly reduce the content of caffeine in tea leaves. Compared with the method for producing the low-caffeine tea leaves by adopting the process at the later stage, the method has the advantages that the safety is guaranteed, and the cost is reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A planting method for reducing the content of caffeine in tea leaves is characterized by comprising the following steps: the method comprises the following steps:

s1, selecting a land with the growth temperature of 20-30 ℃ and the gradient of less than 30 ℃, and adjusting the pH value of the soil to 3.0-4.0 by using acid or alkali; the acid is a 1M hydrochloric acid solution, and the alkali is a 1M sodium hydroxide solution;

s2, after the land is deeply ploughed for 100-150cm, detecting the contents of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus in the soil, and applying base fertilizer to adjust the soil so that the content of the alkaline hydrolysis nitrogen in the soil is lower than 30mg/kg, the content of the quick-acting potassium is 100-130mg/kg, and the content of the available phosphorus is 2.0-3.20 mg/kg; after the land is deeply ploughed, the contents of As, Cr, Cu, Hg and Ni in the soil are detected, the content of As in the soil is lower than 1.2mg/kg, the content of Cr is lower than 36.8mg/kg, the content of Cu is lower than 2.60mg/kg, the content of Hg is lower than 0.012mg/kg, and the content of Ni is lower than 9.50mg/kg, and if the conditions are not met, a new land is replaced;

s4, managing during the growth process of the tea seedlings, including Cd fertilizer application, pest control and trimming; the Cd fertilizer application is that Cd fertilizer is uniformly applied every 2-3 months after planting, so that the Cd content in the soil is 0.1-0.3 mg/kg.

2. The planting method for reducing the content of caffeine in tea leaves according to claim 1, wherein: the pruning is as follows: when the tea seedlings are 30-40cm high, cutting off the new tips at the top ends of the main branches; when the tea seedlings are 50cm-60cm high, the upper branch tips are cut off, and the root necks and the downward and weak branches in the awning tree are cut off.

3. The planting method for reducing the content of caffeine in tea leaves according to claim 1, wherein: the pest control is physical control or biological control.

4. The planting method for reducing the content of caffeine in tea leaves according to claim 1, wherein: the Cd fertilizer is a cadmium reduction fertilizer.