Preparation method of ampelopsis grossedentata extract

Abstract

The invention relates to the technical field of ampelopsis grossedentata extraction, in particular to a preparation method of an ampelopsis grossedentata extract, which comprises the following steps: S1, extraction: heating a certain amount of dried ampelopsis grossedentata leaves for 90-150 seconds under the conditions that water or 70% ethanol is used as an extracting agent, the material-liquid ratio is (1: 30)-(1: 40) and the microwave frequency is 400-1000W to obtain a flavone crude product; s2, purification: dissolving the crude product in boiling water, carrying out suction filtration while the crude product is hot, collecting filtrate, naturally cooling the filtrate, and collecting precipitates; s3, re-purification: dissolving the precipitate in boiling water, carrying out suction filtration while the precipitate is hot, collecting filtrate, naturally cooling the filtrate, collecting the precipitate, and repeating for multiple times. By adopting a microwave extraction method, after the tea leaves are subjected to microwave treatment, cell membranes are broken, part of effective components are dissolved out and attached to the surfaces of the tea leaves, and after the tea leaves are subjected to microwave treatment, the extraction rate is remarkably increased and can reach about 50%. The purity of the flavone compound in the flavone extract is increased to 95% from 50% in a crude product through repeated recrystallization by taking water as a solvent.

Description

Technical Field

[0001] The invention relates to the technical field of rattan tea extraction, and in particular to a method for preparing a rattan tea extract. Background Art

[0002] Ampelopsis grossedentata extract is a natural compound extracted from the tender stems and leaves of Ampelopsis grossedentata, a plant of the grape family. This extract is rich in a variety of biologically active ingredients, the most important of which is dihydromyricetin, in addition to flavonoids such as myricetin and quercetin.

[0003] Due to its rich biological activity, rattan tea extract has a wide range of applications in many fields. In the food industry, rattan tea extract can be used as an additive for new health drinks, giving the product health benefits such as clearing away heat and detoxification, lowering blood sugar, lowering blood lipids, and anti-oxidation. In animal husbandry, rattan tea extract as a feed additive can increase the feed intake and growth performance of animals, while also protecting the liver. In addition, rattan tea extract has also been studied for drug development, with potential anti-arrhythmic, anti-myocardial ischemia, anti-hypertension and other therapeutic effects.

[0004] In the prior art, although water is used as an extractant with low cost, the extraction temperature is high, the extraction time is long, and the flavonoid extraction rate and purity are low, which increases the difficulty of subsequent separation and purification. At the same time, the activity of effective substances such as flavonoids will inevitably be reduced under the action of long-term high temperature. The extraction rate is low when alcohol is used as an extractant, the content of the separated effective substances is small, and there is a problem of residual solvent. Therefore, we propose a method for preparing a rattan tea extract. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a rattan tea extract to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a rattan tea extract, comprising the following steps:

[0007] S1. Extraction: a certain amount of dried rattan tea leaves are heated for 90-150 seconds in water or 70% ethanol as an extractant with a solid-liquid ratio of 1:30-1:40 and a microwave frequency of 400-1000 W to obtain crude flavonoids;

[0008] S2. Purification: dissolve the crude product in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally, and collect the precipitate;

[0009] S3. Purify again: dissolve the precipitate in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally and collect the precipitate, repeat several times.

[0010] Preferably, the extractant in step S1 is water.

[0011] Preferably, the material-liquid ratio in step S1 is 1:35.

[0012] Preferably, in step S1, heating is performed for 90 seconds at a microwave frequency of 500 W.

[0013] Preferably, in step S2, the ratio of crude flavonoids to boiling water is 1:100; the flavonoids are heated in an electric furnace to dissolve, and the heating time does not exceed 5 minutes.

[0014] Preferably, the total number of recrystallizations in steps S3 and S4 is 4-6 times.

[0015] Preferably, the total number of recrystallizations in steps S3 and S4 is 6 times.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts the microwave extraction method. After the tea leaves are treated with microwaves, the cell membrane has been broken, and some effective ingredients have been dissolved and attached to the surface of the tea leaves. From the experimental results, after microwave treatment, the extraction rate is significantly increased and can reach about 50%.

[0017] Dihydromyricetin, the main component of the Ampelopsis serrulata extract, is a polar compound. Its water extract inevitably contains impurities such as tannins, proteins, sugars, salts and pigments. These impurities coexist with the flavonoid extract in a bound or free form, so the total flavonoid content of the Ampelopsis serrulata extract is about 86%. The solubility of dihydromyricetin in hot water at about 100°C is about 20 times that of cold water, and the water heating recrystallization purification method is simple, safe and cheap.

[0018] The tannin content in the raw material is as high as 12%. It is the main substance that produces bitter taste in crude flavonoid extract. After multiple recrystallizations, most of the tannin and pigment remain in the crystallization mother liquor and are removed. After multiple recrystallizations with water as the solvent, the purity of flavonoid compounds in the flavonoid extract increases from 50% in the crude product to 95%. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention provides a technical solution:

[0021] Embodiment 1:

[0022] A method for preparing a rattan tea extract comprises the following steps:

[0023] S1. Extraction: Take 5 portions of 2g of dry rattan tea leaves, use water as the extractant, (use water and 70% ethanol as solvents for extraction, and make a comparative test. In 5 groups of parallel tests, it was found that with water as the solvent, the average yield of total flavonoids was 35.1%; with ethanol as the solvent, the average yield of total flavonoids was 35.7%. Through the comparison of the yields, it was found that the solvent had little effect on microwave extraction, so water was selected as the extraction solvent.) The solid-liquid ratio was 1:20, 1:25, 1:30, 1:35, 1:40, and heated for 90 seconds at a microwave frequency of 400W to obtain crude flavonoids; the flavonoid yields in the crude products were 28%, 34%, 36%, 44%, and 39%, respectively.

[0024] S2. Purification: Dissolve the crude product in boiling water, the ratio of crude flavonoids to boiling water is 1:100, that is, add 1g crude product to 100mL boiling water; heat it in an electric furnace to dissolve it, and the heating time shall not exceed 5min. Filter while hot, collect the filtrate, let the filtrate cool naturally, and collect the precipitate; the solubility of dihydromyricetin in hot water at about 100℃ is about 20 times that of cold water, and the water heating recrystallization purification method is simple, safe and cheap.

[0025] S3. Purify again: dissolve the precipitate in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally and collect the precipitate, repeat several times.

[0026] In the extraction process of rattan tea extract, there is a corresponding balance between the amount of solvent used and the dissolution of the substance, that is, there is a problem of (saturated) dissolution. The minimum amount of solvent used is to ensure that the material is just completely immersed. As the amount of solvent increases, the concentration difference between the solvent and the material becomes larger and larger, the substance dissolves more and more easily, and the dissolution amount increases accordingly. At this time, although the output of the extract will increase, the relative content of the active ingredients will decrease. It can be seen that when the material-liquid ratio is 1:35, the total flavonoid yield is the highest.

[0027] Embodiment 2:

[0028] S1. Extraction: Take 5 portions of 2g dry rattan tea leaves, use water as the extractant, (water and 70% ethanol were used as solvents for extraction, and a comparative test was conducted. In 5 groups of parallel experiments, it was found that with water as the solvent, the average yield of total flavonoids was 35.1%; with ethanol as the solvent, the average yield of total flavonoids was 35.7%. Through the comparison of the yields, it was found that the solvent had little effect on microwave extraction, so water was selected as the extraction solvent.) The solid-liquid ratio was 1:35, and the mixture was heated at a microwave frequency of 400W for 30s, 60s, 90s, 120s, and 150s respectively to obtain crude flavonoids; the flavonoid yields in the crude products were 14%, 31%, 44%, 42%, and 40%, respectively.

[0029] S2. Purification: Dissolve the crude product in boiling water, the ratio of crude flavonoids to boiling water is 1:100, that is, add 1g crude product to 100mL boiling water; heat it in an electric furnace to dissolve it, and the heating time shall not exceed 5min. Filter while hot, collect the filtrate, let the filtrate cool naturally, and collect the precipitate; the solubility of dihydromyricetin in hot water at about 100℃ is about 20 times that of cold water, and the water heating recrystallization purification method is simple, safe and cheap.

[0030] S3. Purify again: dissolve the precipitate in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally and collect the precipitate, repeat several times.

[0031] With water as the solvent and other conditions unchanged, different microwave irradiation times will affect the temperature of the liquid and the dissolution of the effective ingredients. As the continuous microwave irradiation time increases, the yield of flavonoids will gradually increase, and there is a maximum value at 90s. The most direct impact of the extension of microwave irradiation time is the increase of dissolved matter, because as time increases, the structure of cells in the material is affected to a greater extent, so the product yield increases. However, since the maximum dissolution amount of the effective ingredients is limited under this condition, the extraction rate of flavonoids does not change much after a period of microwave irradiation. On the other hand, if the microwave time is too long, the rattan tea leaves may be burned or burnt, affecting the extraction rate. Therefore, it can be seen that choosing 90s can achieve a better extraction purpose. It can be seen that when the heating time is 90s, the total flavonoid yield is the highest.

[0032] Embodiment three:

[0033] S1. Extraction: Take 5 portions of 2g dry rattan tea leaves, use water as the extractant, (extraction was carried out with water and 70% ethanol as solvents for comparative experiments. In 5 groups of parallel experiments, it was found that with water as the solvent, the average yield of total flavonoids was 35.1%; with ethanol as the solvent, the average yield of total flavonoids was 35.7%. Through the comparison of the yields, it was found that the solvent had little effect on microwave extraction, so water was selected as the extraction solvent.) The solid-liquid ratio was 1:35, and heated for 90s at microwave frequencies of 100W, 300W, 500W, 800W, and 1000W, respectively, to obtain crude flavonoids; the flavonoid yields in the crude products were 31%, 35%, 44%, 40%, and 39%, respectively.

[0034] S2. Purification: Dissolve the crude product in boiling water, the ratio of crude flavonoids to boiling water is 1:100, that is, add 1g crude product to 100mL boiling water; heat it in an electric furnace to dissolve it, and the heating time shall not exceed 5min. Filter while hot, collect the filtrate, let the filtrate cool naturally, and collect the precipitate; the solubility of dihydromyricetin in hot water at about 100℃ is about 20 times that of cold water, and the water heating recrystallization purification method is simple, safe and cheap.

[0035] S3. Purify again: dissolve the precipitate in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally and collect the precipitate, repeat several times.

[0036] The principle of microwave extraction is that polar molecules or dipole molecules produce ultra-high-speed rotation of about 490 million times per second under the action of microwave field, polar components produce dipole eddy current, ion conduction and ultra-high frequency friction to generate high temperature in a very short time, which has the following effects: first, it strengthens the transfer process, heat is obtained through microwave conversion without transfer problems, thus achieving high-intensity uniform heating; second, polar molecules in plants absorb microwaves to generate heat, vaporize or expand, and the increase in internal osmotic pressure destroys the cell structure, making the diffusion channel larger and making extraction easier. In summary, when the microwave frequency is 400W, the total flavonoids yield is the highest.

[0037] Embodiment 4:

[0038] S1. Extraction: Take 2g of dry rattan tea leaves, use water as the extractant, (extraction was carried out with water and 70% ethanol as solvents for comparative experiments. In 5 groups of parallel experiments, it was found that with water as the solvent, the average yield of total flavonoids was 35.1%; with ethanol as the solvent, the average yield of total flavonoids was 35.7%. Through the comparison of the yields, it was found that the solvent had little effect on microwave extraction, so water was selected as the extraction solvent.) The solid-liquid ratio was 1:35, and heated at a microwave frequency of 500W for 90s to obtain a crude flavonoid product; the flavonoid yield in the crude product was 50%.

[0039] S2. Purification: Dissolve the crude product in boiling water, the ratio of crude flavonoids to boiling water is 1:100, that is, add 1g crude product to 100mL boiling water; heat it in an electric furnace to dissolve it, and the heating time shall not exceed 5min. Filter while hot, collect the filtrate, let the filtrate cool naturally, and collect the precipitate; the solubility of dihydromyricetin in hot water at about 100℃ is about 20 times that of cold water, and the water heating recrystallization purification method is simple, safe and cheap.

[0040] S3. Purify again: dissolve the precipitate in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally and collect the precipitate, repeat several times.

[0041] Using water as solvent, the recrystallization method can effectively improve the purity of flavonoid compounds. After 6 recrystallizations, the purity of flavonoids increased from 50% of the crude product to 95%. The purity of flavonoid compounds increased linearly with the increase in the number of recrystallizations, but the increase in the purity of the product slowed down after 4 recrystallizations. The yield also decreased with the increase in the number of recrystallizations. The crystals of flavonoid compounds in the water phase were needle-shaped crystals.

[0042] The present invention adopts microwave extraction method. After the tea leaves are treated with microwaves, the cell membrane has been broken, and some effective components have been dissolved and attached to the surface of the tea leaves. From the experimental results, after microwave treatment, the extraction rate is significantly increased to about 50%. After multiple recrystallizations using water as the solvent, the purity of the flavonoid compounds in the flavonoid extract is increased from 50% in the crude product to 95%.

[0043] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a rattan tea extract, characterized in that: The steps include: S1. Extraction: a certain amount of dried rattan tea leaves are heated for 90-150 seconds in water or 70% ethanol as an extractant with a solid-liquid ratio of 1:30-1:40 and a microwave frequency of 400-1000 W to obtain crude flavonoids; S2. Purification: dissolve the crude product in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally, and collect the precipitate; S3. Purify again: dissolve the precipitate in boiling water, filter while hot, collect the filtrate, let the filtrate cool naturally and collect the precipitate, repeat several times.

2. The method for preparing a rattan tea extract according to claim 1, characterized in that: The extractant in step S1 is water.

3. The method for preparing a rattan tea extract according to claim 1, characterized in that: The material-liquid ratio in step S1 is 1:

35.

4. The method for preparing a rattan tea extract according to claim 1, characterized in that: In the step S1, heating is performed for 90 seconds at a microwave frequency of 500 W.

5. The method for preparing a rattan tea extract according to claim 1, characterized in that: In the step S2, the ratio of the crude flavonoids to boiling water is 1:100; the flavonoids are heated in an electric furnace to dissolve the flavonoids, and the heating time does not exceed 5 minutes.

6. The method for preparing a rattan tea extract according to claim 1, characterized in that: The total number of recrystallizations in steps S3 and S4 is 4-6 times.

7. The method for preparing a rattan tea extract according to claim 6, characterized in that: The total number of recrystallizations in steps S3 and S4 is 6.