CN104351444A - Method for selecting and collecting aroma components in green tea leaves and aroma components prepared according to method - Google Patents

Abstract

The invention relates to a method for selecting and collecting aroma components in green tea leaves. The steps are as follows: 1) Put the green tea in a container, add water, heat to collect the tea aroma, introduce the tea aroma into a collection bottle containing liquid nitrogen, and drink the tea soup Stop heating after slight boiling; take the tea soup and pour it into the collection bottle, combine the tea soup in the round bottom flask and the green tea aroma components in the collection bottle to obtain the green tea water before the solid phase extraction column; 2) Take the green tea water and Dilute the deionized water according to a certain dilution factor and load the sample on the LiChrolutEN solid-phase extraction column. After the sample is loaded, use ultrapure water to elute the solid-phase extraction column; pump the solid-phase extraction column under vacuum and then use dichloromethane to elute the extraction Volatile components in the column; the dichloromethane eluate is concentrated after drying, which is the final green tea essential oil. According to the method of the invention, there is no solvent residue in the extracted aroma-causing substances, no special odor, fresh and rich aroma, and higher extraction rate.

Description

A method for selecting and collecting aroma components in green tea leaves and aroma substances prepared by the method

technical field

The invention belongs to the technical field of extraction of natural active components, and in particular relates to a method for selecting and collecting aroma components in green tea leaves and aroma substances prepared by the method.

Background technique

Tea tree tea is a dicotyledonous plant, about 30 genera and 500 species, distributed in tropical and subtropical regions. There are 14 genera and 397 species in my country, which are mainly produced in the south of the Yangtze River. Among them, the tea genus Camellia and the Heshu genus Schima are of great economic value. As one of the three major beverages in the world, tea is not only an excellent health drink, but also a good traditional Chinese medicine; among them, the tea without fermentation (zero fermentation degree) is called green tea, and the proven green tea contains 300 A variety of chemical components, such as tea polyphenols, amino acids, caffeine, vitamins, pectin, organic acids, lipopolysaccharides, proteins, aromatic compounds, minerals, sugars, enzymes, pigments, etc., can play a role in heatstroke prevention. Mattress, refreshing, stomach nourishing, cancer prevention, weight loss, bodybuilding and other functions.

In addition to water, the main active ingredients in green tea water are a large number of non-volatile substances such as tea polyphenols, sugars, pigments, amino acids, caffeine, vitamins, etc. Generally speaking, the total content of aroma substances does not exceed 2% of the tea body. The aroma components of green tea research data show that there are nearly 600 kinds of aroma substances, and the content distribution of these aroma substances ranges from ng/L to g/L The grades vary. Among these trace aroma substances, 99% are common alcohols, acids and esters in green tea water, while the remaining 1% components that determine the aroma characteristics of tea are made up of nearly a hundred kinds of substances in μg/L or even ng /L of aroma substances. The selective collection of these trace or even trace aroma substances that contribute significantly to the characteristic aroma of green tea water is the most difficult part of the current tea sample pretreatment technology.

At present, the common collection methods of tea aroma substances include liquid-liquid extraction, solid-phase extraction, headspace sampling, solid-phase microextraction, stirring rod adsorption extraction, etc. In the comparative study of these methods, it can be seen that each has advantages and disadvantages. Liquid-liquid extraction is the most widely used extraction technology in aroma research. It has the advantages of large processing capacity, various solvent choices, and higher concentration multiples. It is mostly used for qualitative analysis of tea aroma compounds; Due to the disadvantages of high solvent usage and poor quantitative accuracy, there is an urgent need for more convenient, safe and efficient extraction and collection of aroma technology. Headspace sampling, solid-phase microextraction and stirring bar adsorption extraction have the characteristics of simple operation, fast, solvent-free, and easy to automate, and are suitable for quantitative analysis of a large number of samples, but due to the difference in selectivity preference of adsorbent materials, it is easy to cause some These methods are difficult to realize the comprehensive extraction and enrichment of tea aroma substances. Solid-phase extraction is currently the most widely used sample pretreatment technology, and is widely used in the analysis of samples in the fields of food, medicine, tobacco, and the environment. Solid-phase extraction has the characteristics of flexible operation, various types of adsorption materials, less solvent usage, and high concentration multiples. It is especially suitable for the separation and enrichment of trace and trace important aroma compounds in tea. Due to the complexity of the types and properties of the aroma components of green tea water, and the large concentration span of aroma compounds, there is currently no pretreatment method that meets all needs and completes the enrichment and concentration of all aroma substances at one time.

Contents of the invention

In order to solve the above-mentioned technical problems, the first object of the present invention is to provide a method for selecting and collecting aroma components in green tea leaves and the method. The second object of the present invention is to provide the aromatizing substance prepared by the above method. The method of the present invention is more suitable for extracting aroma components with very few components in tea leaves and a large concentration span of aroma compounds. There is no solvent residue in the extracted aroma substances, no special odor, fresh and strong aroma, and higher extraction rate. .

In order to achieve the above-mentioned first purpose, the present invention adopts the following technical solutions:

A method for selecting and collecting aroma components in green tea leaves, the method comprising the following steps:

1) Put the green tea in the adding container, add water, heat to collect the tea fragrance, introduce the tea fragrance into the collection bottle containing liquid nitrogen, stop heating the tea soup after 1~10 minutes of slight boiling; take a certain amount of tea soup and pour it into the collection bottle Inside, combine the tea soup in the round bottom flask and the green tea aroma components in the collection bottle to obtain the green tea water before the solid phase extraction column;

2) Take green tea water, dilute with deionized water according to a certain dilution factor, and then load the sample on the LiChrolut EN solid-phase extraction column. During the control process, the flow rate of the sample is not higher than 5.0 mL/min, and after the sample is loaded, it is eluted with ultrapure water Solid-phase extraction column; pump the solid-phase extraction column under vacuum and elute the volatile components in the extraction column with dichloromethane; the dichloromethane eluate is dried and concentrated to obtain the final green tea essential oil.

Preferably, the green tea is Mingqian green tea.

As a preference, the green tea in step 1) is pre-treated: weigh a certain amount of dry green tea, put it in a vacuum drying oven at 45°C and dry it to near absolute dryness, then adjust the temperature of the vacuum drying oven to 105°C and bake it to constant Heavy, crushed, sieved, and set aside.

Preferably, the particle size of the green tea after sieving is 40-80 mesh.

Preferably, the solid-liquid ratio of green tea and water in step 1) is selected to be 1:10-1:30.

Preferably, the microboiling time in step 1) is 2-6 minutes.

As a preference, before loading the LiChrolut EN solid-phase extraction column in the step 2), 20 mL of dichloromethane, 20 mL of methanol and 30 mL of ultrapure water are used for activation treatment respectively.

As a preference, the sample dilution factor in step 2) is 1 to 5 times.

Preferably, the sample loading flow rate in step 2) is 1.0-3.0 mL/min.

In order to achieve the above-mentioned second purpose, the present invention adopts the following technical solutions:

Aroma-inducing substances in the green tea leaves prepared by the method described in any one of the above technical solutions.

Because tea is not an aromatic plant, it contains very few aroma components and the concentration of aroma compounds spans a large range, so it is very challenging to extract the aroma of tea aroma raw materials. The present invention adopts the selective adsorption of LiChrolut EN resin, which has a good adsorption effect on aroma compounds, but has a poor adsorption effect on tea polyphenols, sugars, pigments, amino acids, caffeine, vitamins, etc., which are more abundant in the sample. , the process can minimize the loss of the target aroma components, and finally get the natural tea aroma extract. The finished green tea essential oil has no solvent residue, no special smell, fresh and rich aroma, and higher extraction rate. The extraction rate of the Mingqian green tea essential oil determined by the present invention can reach up to 8.26%. In the DPPH free radical system, the IC ₅₀ of the Mingqian green tea essential oil is 51.23 μg/mL.

Detailed ways

Examples are given below to further illustrate the present invention.

Example 1

A method for selecting and collecting aroma components in green tea leaves, the method comprising the following steps:

(1) Filling of solid-phase extraction: self-packing LiChrolut EN (1000 mg) solid-phase extraction column from Merck Millipore, Germany, which has good adsorption function for tea aroma;

(2) Activation treatment of LiChrolut EN solid-phase extraction column: 20 mL dichloromethane, 20 mL methanol and 30 mL ultrapure water were used for activation treatment before sample loading

(3) Pre-treatment of Mingqian green tea (Zhejiang production area): Weigh a certain amount of dried Mingqian green tea, put it in a vacuum drying oven at 45°C and dry it until it is almost dry, then adjust the temperature of the vacuum drying oven to 105°C and dry it to Constant weight, and after sieving according to the selection requirements of a certain Mingqian green tea particle size, set aside;

(4) Preparation of tea: Accurately weigh 60 meshes of Mingqian green tea, place it in a 1000 mL round-bottomed flask covered with an electric heating mantle, add boiling water according to the ratio of material to liquid of 1:20, and discharge the tea from the round-bottomed flask The tea fragrance is introduced into a collection bottle containing liquid nitrogen through a glass tube. After the tea soup has been boiled for 4 minutes, the round bottom flask device is removed; a certain amount of tea soup is poured into the collection bottle, and the tea soup in the round bottom flask and the tea soup in the collection bottle are combined. The green tea aroma components are obtained from the Mingqian green tea water before the solid-phase extraction column;

(5) Sample loading: Take a certain amount of Mingqian green tea water, dilute it with deionized water according to the dilution factor of 2 times, and then load the sample on the LiChrolut EN solid-phase extraction column. During the control process, the sample loading flow rate is 2.0 mL/min. After the completion, use 50mL ultrapure water to elute the residual Mingqian green tea water, pigment, sugar and other substances in the solid phase extraction column. Dry the solid-phase extraction column at a vacuum of 0.1 MPa for 10 min, and then use 20 mL of dichloromethane to elute the volatile components in the extraction column; the dichloromethane eluate is dried over anhydrous sodium sulfate and then concentrated under nitrogen blowing to 0.5mL is the final Mingqian green tea essential oil.

The extraction rate of the tea essential oil of Mingqian green tea was determined to be 8.26%. In the DPPH free radical system, the IC ₅₀ of the tea essential oil of Mingqian green tea was 51.23μg/mL.

Example 2

A method for selecting and collecting aroma components in green tea leaves, the method comprising the following steps:

(1) Filling of solid-phase extraction: self-packing LiChrolut EN (1000 mg) solid-phase extraction column from Merck Millipore, Germany, which has good adsorption function for tea aroma;

(2) Activation treatment of LiChrolut EN solid-phase extraction column: 20 mL dichloromethane, 20 mL methanol and 30 mL ultrapure water were used for activation treatment before sample loading

(3) Pre-treatment of Mingqian green tea (Zhejiang production area): Weigh a certain amount of dried Mingqian green tea, put it in a vacuum drying oven at 45°C and dry it until it is almost dry, then adjust the temperature of the vacuum drying oven to 105°C and dry it to Constant weight, and after sieving according to the selection requirements of a certain Mingqian green tea particle size, set aside;

(4) Preparation of tea: Accurately weigh 40 meshes of Mingqian green tea, place it in a 1000 mL round-bottomed flask covered with an electric heating mantle, add boiling water according to the ratio of material to liquid of 1:10, and discharge the tea from the round-bottomed flask The tea fragrance is introduced into a collection bottle containing liquid nitrogen through a glass tube. After the tea soup has been boiled for 6 minutes, the round bottom flask device is removed; a certain amount of tea soup is poured into the collection bottle, and the tea soup in the round bottom flask and the tea soup in the collection bottle are combined. The green tea aroma components are obtained from the Mingqian green tea water before the solid-phase extraction column;

(5) Sample loading: Take a certain amount of Mingqian green tea water, dilute it with deionized water according to the dilution factor of 5 times, and then load the sample on the LiChrolut EN solid-phase extraction column. During the control process, the sample loading flow rate is 3.0 mL/min. After the completion, use 50mL ultrapure water to elute the residual Mingqian green tea water, pigment, sugar and other substances in the solid phase extraction column. Dry the solid-phase extraction column at a vacuum of 0.1 MPa for 10 min, and then use 20 mL of dichloromethane to elute the volatile components in the extraction column; the dichloromethane eluate is dried over anhydrous sodium sulfate and then concentrated under nitrogen blowing to 0.5mL is the final Mingqian green tea essential oil.

The extraction rate of the tea essential oil of Mingqian green tea was determined to be 7.76%. In the DPPH free radical system, the IC ₅₀ of the tea essential oil of Mingqian green tea was 52.05μg/mL.

Example 3

A method for selecting and collecting aroma components in green tea leaves, the method comprising the following steps:

(1) Filling of solid-phase extraction: self-packing LiChrolut EN (1000 mg) solid-phase extraction column from Merck Millipore, Germany, which has good adsorption function for tea aroma;

(2) Activation treatment of LiChrolut EN solid-phase extraction column: 20 mL dichloromethane, 20 mL methanol and 30 mL ultrapure water were used for activation treatment before sample loading

(3) Pre-treatment of Mingqian green tea (Zhejiang production area): Weigh a certain amount of dried Mingqian green tea, put it in a vacuum drying oven at 45°C and dry it until it is almost dry, then adjust the temperature of the vacuum drying oven to 105°C and dry it to Constant weight, and after sieving according to the selection requirements of a certain Mingqian green tea particle size, set aside;

(4) Preparation of tea: Accurately weigh 80 mesh Mingqian green tea, place it in a 1000 mL round-bottomed flask covered with an electric heating mantle, add boiling water according to the ratio of material to liquid of 1:30, and discharge the tea from the round-bottomed flask The tea fragrance is introduced into a collection bottle containing liquid nitrogen through a glass tube, and the tea soup is removed from the round-bottom flask device after 2 minutes of slight boiling time; a certain amount of tea soup is poured into the collection bottle, and the tea soup in the round-bottom flask and the tea soup in the collection bottle are combined. The green tea aroma components are obtained from the Mingqian green tea water before the solid-phase extraction column;

(5) Sample loading: Take a certain amount of Mingqian green tea water, dilute it with deionized water according to the dilution factor of 3 times, and then load the sample on the LiChrolut EN solid-phase extraction column. During the control process, the sample loading flow rate is 1.0 mL/min. After the completion, use 50mL ultrapure water to elute the residual Mingqian green tea water, pigment, sugar and other substances in the solid phase extraction column. Dry the solid-phase extraction column at a vacuum of 0.1 MPa for 10 min, and then use 20 mL of dichloromethane to elute the volatile components in the extraction column; the dichloromethane eluate is dried over anhydrous sodium sulfate and then concentrated under nitrogen blowing to 0.5mL is the final Mingqian green tea essential oil.

The extraction rate of the tea essential oil of Mingqian green tea was determined to be 7.88%. In the DPPH free radical system, the IC ₅₀ of the tea essential oil of Mingqian green tea was 52.38μg/mL.

Example 4

A method for selecting and collecting aroma components in green tea leaves, the method comprising the following steps:

(1) Filling of solid-phase extraction: self-packing LiChrolut EN (1000 mg) solid-phase extraction column from Merck Millipore, Germany, which has good adsorption function for tea aroma;

(2) Activation treatment of LiChrolut EN solid-phase extraction column: 20 mL dichloromethane, 20 mL methanol and 30 mL ultrapure water were used for activation treatment before sample loading

(3) Pre-treatment of Mingqian green tea (Zhejiang production area): Weigh a certain amount of dried Mingqian green tea, put it in a vacuum drying oven at 45°C and dry it until it is almost dry, then adjust the temperature of the vacuum drying oven to 105°C and dry it to Constant weight, and after sieving according to the selection requirements of a certain Mingqian green tea particle size, set aside;

(4) Preparation of tea: Accurately weigh 60 meshes of Mingqian green tea, place it in a 1000 mL round-bottomed flask covered with an electric heating mantle, add boiling water according to the ratio of material to liquid of 1:20, and discharge the tea from the round-bottomed flask The tea fragrance is introduced into a collection bottle containing liquid nitrogen through a glass tube, and the tea soup is removed from the round-bottom flask device after 2 minutes of slight boiling time; a certain amount of tea soup is poured into the collection bottle, and the tea soup in the round-bottom flask and the tea soup in the collection bottle are combined. The green tea aroma components are obtained from the Mingqian green tea water before the solid-phase extraction column;

(5) Sample loading: Take a certain amount of Mingqian green tea water, dilute it with deionized water according to the dilution factor of 2 times, and then load the sample on the LiChrolut EN solid-phase extraction column. During the control process, the sample loading flow rate is 3.0 mL/min. After the completion, use 50mL ultrapure water to elute the residual Mingqian green tea water, pigment, sugar and other substances in the solid phase extraction column. Dry the solid-phase extraction column at a vacuum of 0.1 MPa for 10 min, and then use 20 mL of dichloromethane to elute the volatile components in the extraction column; the dichloromethane eluate is dried over anhydrous sodium sulfate and then concentrated under nitrogen blowing to 0.5mL is the final Mingqian green tea essential oil.

The extraction rate of the tea essential oil of Mingqian green tea was determined to be 8.17%. In the DPPH free radical system, the IC ₅₀ of the tea essential oil of Mingqian green tea was 55.02μg/mL.

Claims (10)

1. A method for selecting and collecting aroma components in green tea leaves, characterized in that the method comprises the following steps: 1) Put the green tea in the adding container, add water, heat to collect the tea fragrance, introduce the tea fragrance into the collection bottle containing liquid nitrogen, stop heating the tea soup after 1~10 minutes of slight boiling; take a certain amount of tea soup and pour it into the collection bottle Inside, combine the tea soup in the round bottom flask and the green tea aroma components in the collection bottle to obtain the green tea water before the solid phase extraction column; 2) Take green tea water, dilute with deionized water according to a certain dilution factor, and then load the sample on the LiChrolut EN solid-phase extraction column. During the control process, the flow rate of the sample is not higher than 5.0 mL/min, and after the sample is loaded, it is eluted with ultrapure water Solid-phase extraction column; pump the solid-phase extraction column under vacuum and elute the volatile components in the extraction column with dichloromethane; the dichloromethane eluate is dried and concentrated to obtain the final green tea essential oil. 2. A method for selecting and collecting aroma components in green tea leaves according to claim 1, wherein the green tea is selected from Mingqian green tea. 3. A method for selecting and collecting aroma-causing components in green tea leaves according to claim 1 or 2, characterized in that: in step 1), the green tea is pre-treated: weigh a certain amount of dry green tea and place it in a vacuum at 45°C Dry in a drying oven until nearly dry, then adjust the temperature of the vacuum drying oven to 105°C and dry to constant weight, pulverize, sieve, and set aside. 4. A method for selecting and collecting aroma components in green tea leaves according to claim 3, characterized in that: the green tea has a particle size of 40 to 80 meshes after sieving. 5. A method for selecting and collecting aroma components in green tea leaves according to claim 1 or 2, characterized in that: in step 1), the solid-liquid ratio of green tea to water is selected to be 1:10~1:30. 6. A method for selecting and collecting aroma components in green tea leaves according to claim 1 or 2, characterized in that the microboiling time in step 1) is 2-6 minutes. 7. A method for selecting and collecting aroma components in green tea leaves according to claim 1, characterized in that: in step 2), 20 mL of dichloromethane, 20 mL of dichloromethane, 20 mL methanol and 30mL ultrapure water for activation. 8. A method for selecting and collecting aroma components in green tea leaves according to claim 1 or 7, characterized in that: in step 2), the dilution factor of the sample is 1 to 5 times. 9. A method for selecting and collecting aroma components in green tea leaves according to claim 1 or 7, characterized in that: in step 2), the sample loading flow rate is 1.0-3.0 mL/min. 10. Aroma-inducing substances in the green tea leaves prepared by the method according to any one of claims 1 to 9.