阅读说明：本技术 一种杜鹃花色素的提取方法 (Method for extracting azalea pigment ) 是由 周艳 李靖 童琪 于 2020-12-29 设计创作，主要内容包括：本发明属于植物色素提取技术领域,公开了一种杜鹃花色素的提取方法,包括：对杜鹃花进行清洗、浸泡、煎煮两次,并合并煎液,冷却至室温；向合并后的煎煮液中加入乙醇溶液于常温下进行超声提取；并对提取液中的乙醇进行回收；向回收后的乙醇提取液中加入水和乙酸乙酯,萃取,合并萃取液后留取下层液体；利用树脂对留取的下层液体中的杜鹃花色素进行吸附；并对所述树脂进行洗脱得到洗脱液；对得到洗脱液进行超滤并得到洗脱滤液,对洗脱滤液进行干燥即可得到杜鹃花色素。本发明的提取方法简单、容易、能够有效提高提取率,且成本低；同时能够对杜鹃花中包含的其他相对色素进行有效清除,提取的色素纯度高。(The invention belongs to the technical field of plant pigment extraction, and discloses a method for extracting rhododendron pigment, which comprises the following steps: cleaning, soaking and decocting azalea twice, combining the decoctions, and cooling to room temperature; adding an ethanol solution into the combined decoction, and performing ultrasonic extraction at normal temperature; recovering ethanol in the extract; adding water and ethyl acetate into the recovered ethanol extract, extracting, and mixing the extracts to obtain a lower layer liquid; adsorbing the azalea pigment in the retained lower-layer liquid by using resin; eluting the resin to obtain an eluent; and (3) carrying out ultrafiltration on the obtained eluent to obtain elution filtrate, and drying the elution filtrate to obtain the rhododendron pigment. The extraction method is simple and easy, can effectively improve the extraction rate, and has low cost; meanwhile, other relative pigments contained in the rhododendron can be effectively removed, and the purity of the extracted pigment is high.)

1. A method for extracting azalea pigment is characterized by comprising the following steps:

collecting bloomed rhododendrons in a blooming period, placing the collected rhododendrons in a refrigerating chamber, adjusting refrigerating humidity to 40-60%, and refrigerating the rhododendrons by keeping freshness of the rhododendrons; during extraction, separating petals, stamens and calyces of collected rhododendrons, and reserving the rhododendron petals for later use; soaking the azalea with clear water, and cleaning pollen, dust and other impurities on the surface to obtain pure azalea petals;

soaking the cleaned rhododendron in clear water, decocting the rhododendron and the soaking solution for 2-3 hours after soaking, and filtering to obtain a primary decoction; collecting the filtered filter residue, adding water with the mass being 10 times that of the filter residue into the filter residue, decocting again for 50-55 min, and filtering to obtain a filtrate; mixing the two filtrates, standing the mixed filtrate, cooling to room temperature, and removing bottom precipitate to obtain flos Rhododendri Simsii extract;

placing the azalea extracting solution into a frying pan, and heating and concentrating the azalea extracting solution to obtain an azalea concentrated solution; placing the concentrated azalea solution obtained through concentration in a reflux extraction device, adding an ethanol solution with the volume fraction of 70-75% into the reflux extraction device, and opening the reflux extraction device to perform reflux extraction at normal temperature after the azalea concentrated solution and the ethanol solution are completely and uniformly mixed to obtain a reflux extracting solution;

step four, collecting the reflux extracting solution, and decompressing the reflux extracting solution to recover ethanol in the reflux extracting solution to obtain a pure rhododendron extracting solution; adding water and ethyl acetate into the pure rhododendron extract, and uniformly stirring to obtain a mixed solution; carrying out ultrasonic dispersion on the mixed solution by adopting an ultrasonic mode, extracting the dispersed mixed solution for 3-4 times, combining the extract solutions after the extraction is finished, standing at room temperature, and reserving the lower layer liquid;

step five, adsorbing the azalea pigment in the reserved lower-layer liquid by using resin; washing the surface of the resin with clear water, draining after the resin is cleaned, and putting the resin into an elution tank; adding saline water with the mass fraction of 0.6-0.9% and the same mass as that of the resin into an elution tank, heating to 55-60 ℃, and carrying out primary elution; carrying out secondary elution on the resin filtered out by the primary elution by using the primary eluent and an ethanol solution; carrying out tertiary elution on the resin filtered out in the secondary elution by using the secondary eluent and the newly added ethanol solution to obtain eluent;

and sixthly, carrying out ultrafiltration on the eluent obtained by elution to obtain elution filtrate, placing the elution filtrate in a vacuum drying oven for drying under reduced pressure, wherein the drying pressure is 0-0.1 Mpa, the drying temperature is 45-50 ℃, the drying time is 10-45 min, and grinding the obtained solid substance after drying to obtain powdery azalea pigment.

2. The method for extracting azalea pigment according to claim 1, wherein the step one, soaking the washed azalea in clear water, comprises: adding clear water 25 times of the mass of the rhododendron for soaking for 50 min.

3. The method for extracting azalea pigment according to claim 1, wherein the concentration of the azalea concentrate in the third step is 1.2 g/L.

4. The method for extracting azalea pigment according to claim 1, wherein in the third step, the addition amount of ethanol is 3 times of the volume of the azalea concentrated solution; the ethanol concentration was 90 vt%.

5. The method for extracting azalea pigment according to claim 1, wherein the step four, wherein the recovering ethanol from the refluxed extract under reduced pressure comprises: ethanol was removed by vacuum rotary evaporator at 37 ℃ under 1 atm.

6. The method for extracting azalea pigment according to claim 1, wherein in the fourth step, the mixed solution is subjected to ultrasonic dispersion by an ultrasonic method, wherein the ultrasonic frequency is 50-60 kHz, and the ultrasonic time is 10-15 min.

7. The method for extracting azalea pigment according to claim 1, wherein in the fifth step, the volume ratio of the resin to the ethanol solution is 1: 7-8, and the ethanol concentration is 40%.

8. The method for extracting azalea pigment according to claim 1, wherein in the fifth step, the volume ratio of the resin to the ethanol solution is 1:3, and the ethanol concentration is 60%.

9. The method for extracting rhododendron pigment according to claim 1, wherein in the sixth step, the step of performing ultrafiltration on the eluted eluent to obtain an elution filtrate comprises the following steps:

1) diluting the eluate with purified water, filtering, and sterilizing to obtain filtered feed liquid;

2) concentrating the filtered feed liquid;

3) keeping the volume of the feed liquid unchanged, and adding purified water in a flowing manner to wash and filter the feed liquid;

4) after the purification and water washing and filtration are finished, the feed liquid is washed and filtered by flowing sodium chloride solution, and then the elution filtrate is obtained.

10. The method for extracting azalea pigment according to claim 9, wherein in the step 3), the amount of the purified water is 7-9 times of the volume of the feed liquid.

Technical Field

The invention belongs to the technical field of plant pigment extraction, and particularly relates to a method for extracting rhododendron pigment.

Background

At present: the edible pigment is one kind of pigment and is food additive capable of changing the color of food. The edible pigment is divided into natural pigment and artificial pigment, the natural edible pigment is pigment directly extracted from animal and plant tissues and is harmless to human body, the artificial edible pigment is prepared by taking aniline dye separated from coal tar as a raw material, and the artificial synthetic pigment is harmful to human body because of being easy to induce poisoning, diarrhea and even cancer, so that the artificial edible pigment cannot be used more or as little as possible.

The plant pigment is a colored substance extracted from roots, leaves, flowers, trunks or fruits of plants, and a plurality of plant pigments are attractive in color and fragrance, mellow in taste, good in dyeing property, non-toxic and harmless, rich in nutrients required by human bodies, and also have medical care effects. The red pigment is one of natural pigments, the existing rhododendron pigment has the disadvantages of complex extraction process, long extraction time, low extraction rate and higher cost, and does not meet the requirements of environmental protection and safety; the performance of the extracted pigment is not stable enough.

Through the above analysis, the problems and defects of the prior art are as follows: the existing extraction process of azalea pigment is complex, the extraction time is long, the extraction rate is low, the cost is higher, and the requirements of environmental protection and safety are not met; the performance of the extracted pigment is not stable enough.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for extracting rhododendron pigment.

The invention is realized in such a way that the extraction method of the rhododendron pigment comprises the following steps:

collecting bloomed rhododendrons in a blooming period, placing the collected rhododendrons in a refrigerating chamber, adjusting refrigerating humidity to 40-60%, and refrigerating the rhododendrons by keeping freshness of the rhododendrons; during extraction, separating petals, stamens and calyces of collected rhododendrons, and reserving the rhododendron petals for later use; soaking the azalea with clear water, and cleaning pollen, dust and other impurities on the surface to obtain pure azalea petals;

soaking the cleaned rhododendron in clear water, decocting the rhododendron and the soaking solution for 2-3 hours after soaking, and filtering to obtain a primary decoction; collecting the filtered filter residue, adding water with the mass being 10 times that of the filter residue into the filter residue, decocting again for 50-55 min, and filtering to obtain a filtrate; mixing the two filtrates, standing the mixed filtrate, cooling to room temperature, and removing bottom precipitate to obtain flos Rhododendri Simsii extract;

placing the azalea extracting solution into a frying pan, and heating and concentrating the azalea extracting solution to obtain an azalea concentrated solution; placing the concentrated azalea solution obtained through concentration in a reflux extraction device, adding an ethanol solution with the volume fraction of 70-75% into the reflux extraction device, and opening the reflux extraction device to perform reflux extraction at normal temperature after the azalea concentrated solution and the ethanol solution are completely and uniformly mixed to obtain a reflux extracting solution;

step four, collecting the reflux extracting solution, and decompressing the reflux extracting solution to recover ethanol in the reflux extracting solution to obtain a pure rhododendron extracting solution; adding water and ethyl acetate into the pure rhododendron extract, and uniformly stirring to obtain a mixed solution; carrying out ultrasonic dispersion on the mixed solution by adopting an ultrasonic mode, extracting the dispersed mixed solution for 3-4 times, combining the extract solutions after the extraction is finished, standing at room temperature, and reserving the lower layer liquid;

step five, adsorbing the azalea pigment in the reserved lower-layer liquid by using resin; washing the surface of the resin with clear water, draining after the resin is cleaned, and putting the resin into an elution tank; adding saline water with the mass fraction of 0.6-0.9% and the same mass as that of the resin into an elution tank, heating to 55-60 ℃, and carrying out primary elution; carrying out secondary elution on the resin filtered out by the primary elution by using the primary eluent and an ethanol solution; carrying out tertiary elution on the resin filtered out in the secondary elution by using the secondary eluent and the newly added ethanol solution to obtain eluent;

and sixthly, carrying out ultrafiltration on the eluent obtained by elution to obtain elution filtrate, placing the elution filtrate in a vacuum drying oven for drying under reduced pressure, wherein the drying pressure is 0-0.1 Mpa, the drying temperature is 45-50 ℃, the drying time is 10-45 min, and grinding the obtained solid substance after drying to obtain powdery azalea pigment.

Further, in the step one, the step of soaking the cleaned rhododendron in clear water comprises the following steps: adding clear water 25 times of the mass of the rhododendron for soaking for 50 min.

Further, in the third step, the concentration of the azalea concentrated solution is 1.2 g/L.

Further, in the third step, the addition amount of the ethanol is 3 times of the volume of the rhododendron concentrated solution; the ethanol concentration was 90 vt%.

Further, in the fourth step, the decompressing and recovering ethanol in the reflux extracting solution includes: ethanol was removed by vacuum rotary evaporator at 37 ℃ under 1 atm.

Further, in the fourth step, ultrasonic dispersion is carried out on the mixed solution by adopting an ultrasonic mode, the ultrasonic frequency is 50-60 kHz, and the ultrasonic time is 10-15 min.

Further, in the fifth step, the volume ratio of the resin to the ethanol solution is 1: 7-8, and the ethanol concentration is 40%.

Further, in the fifth step, the volume ratio of the resin to the ethanol solution is 1:3, and the ethanol concentration is 60%.

Further, in the sixth step, the step of performing ultrafiltration on the eluent obtained by elution to obtain an elution filtrate includes:

1) diluting the eluate with purified water, filtering, and sterilizing to obtain filtered feed liquid;

2) concentrating the filtered feed liquid;

3) keeping the volume of the feed liquid unchanged, and adding purified water in a flowing manner to wash and filter the feed liquid;

4) after the purification and water washing and filtration are finished, the feed liquid is washed and filtered by flowing sodium chloride solution, and then the elution filtrate is obtained.

Further, in the step 3), the using amount of the purified water is 7-9 times of the volume of the feed liquid.

By combining all the technical schemes, the invention has the advantages and positive effects that: the method for extracting the azalea pigment has the advantages of simple and easy industrial process, capability of effectively improving the extraction rate and low cost; meanwhile, other relative pigments contained in the rhododendron can be effectively removed, and the purity of the extracted pigment is high; the rhododendron pigment with high color value, high purity, high quality and long storage life can be obtained.

The resin adsorption method has the advantages of high adsorption rate, good elution effect and low cost; the ultrafiltration method of the invention can thoroughly and effectively remove impurities, bacteria and pyrogen in the liquid and can effectively retain effective components.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.

Fig. 1 is a flow chart of a method for extracting rhododendron pigment according to an embodiment of the invention.

FIG. 2 is a flow chart of the reflux extraction of the rhododendron concentrated solution by adopting the reflux extraction method provided by the embodiment of the invention.

FIG. 3 is a flow chart of the method for extracting, standing and collecting the lower layer liquid of the extract from the pure reflux extract according to the embodiment of the present invention.

Fig. 4 is a flow chart of adsorption and elution of rhododendron pigment in the collected lower layer liquid by using a resin according to an embodiment of the present invention.

Fig. 5 is a flow chart of ultrafiltration of the eluted liquid to obtain the eluted filtrate according to the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a method for extracting rhododendron pigment, and the invention is described in detail with reference to the attached drawings.

As shown in fig. 1, the extraction method of azalea pigment provided by the embodiment of the present invention includes:

s101, collecting bloomed rhododendrons in a blooming period, placing the collected rhododendrons in a refrigerating chamber, adjusting refrigerating humidity to be 40-60%, and refrigerating the rhododendrons by keeping freshness of the rhododendrons.

S102, separating petals, stamens and calyxes of the collected rhododendrons during extraction, and reserving the rhododendron petals for later use; soaking flos Rhododendri Simsii in clear water, and cleaning pollen, dust and other impurities to obtain pure flos Rhododendri Simsii petal.

S103, soaking the cleaned rhododendron in clear water, decocting the rhododendron and the soaking solution for 2-3 hours after soaking, and filtering to obtain a primary decoction; collecting the filtered filter residue, adding water with the mass being 10 times that of the filter residue into the filter residue, decocting again for 50-55 min, and filtering to obtain a filtrate; and combining the two filtrates, standing the combined filtrate, cooling to room temperature, and removing bottom precipitates to obtain the rhododendron extract.

S104, placing the azalea extracting solution into a frying pan, and heating and concentrating the azalea extracting solution to obtain an azalea concentrated solution; reflux extraction is carried out on the rhododendron concentrated solution by adopting a reflux extraction mode to obtain pure reflux extracting solution.

S105, extracting the pure reflux extracting solution, standing, and taking the lower layer liquid of the extracting solution; and adsorbing and eluting the azalea pigment in the retained lower-layer liquid by using resin to obtain an eluent.

S106, carrying out ultrafiltration on the eluent obtained by elution to obtain elution filtrate, placing the elution filtrate in a vacuum drying oven for drying under reduced pressure, wherein the drying pressure is 0-0.1 Mpa, the drying temperature is 45-50 ℃, the drying time is 10-45 min, and grinding the obtained solid substance after drying is finished to obtain powdery azalea pigment.

In step S101, the soaking of the cleaned rhododendron in clean water according to the embodiment of the present invention includes: adding clear water 25 times of the mass of the rhododendron for soaking for 50 min.

In step S103, the concentration of the azalea concentrated solution provided by the embodiment of the invention is 1.2 g/L.

As shown in fig. 2, in step S104, the reflux extraction of the azalea concentrated solution by using the reflux extraction method provided by the embodiment of the present invention includes:

s201, placing the concentrated azalea solution obtained through concentration in a reflux extraction device, and adding an ethanol solution with the volume fraction of 70-75% into the reflux extraction device.

S202, after the azalea concentrated solution and the ethanol solution are completely and uniformly mixed, opening a reflux extraction device to perform reflux extraction at normal temperature to obtain a reflux extraction solution.

S203, collecting the reflux extracting solution, and decompressing the reflux extracting solution to recover ethanol in the reflux extracting solution to obtain the pure rhododendron extracting solution.

In step S201, the addition amount of ethanol provided in the embodiment of the present invention is 3 times the volume of the azalea concentrated solution; the ethanol concentration was 90 vt%.

In step S203, the recovering ethanol from the refluxed extracting solution under reduced pressure according to the embodiment of the present invention includes: ethanol was removed by vacuum rotary evaporator at 37 ℃ under 1 atm.

As shown in fig. 3, in step S105, extracting the pure reflux extract provided by the embodiment of the present invention, and standing to leave the lower layer liquid of the extract, includes:

s301, adding water and ethyl acetate into the pure rhododendron extract, and uniformly stirring to obtain a mixed solution.

S302, carrying out ultrasonic dispersion on the mixed solution in an ultrasonic mode, and extracting the dispersed mixed solution for 3-4 times.

And S303, combining the extraction solutions after the extraction is finished, standing at room temperature, and taking the lower layer liquid.

In step S302, the mixed liquid is subjected to ultrasonic dispersion in an ultrasonic mode, wherein the ultrasonic frequency is 50-60 kHz, and the ultrasonic time is 10-15 min.

As shown in fig. 4, in step S105, the adsorption and elution of rhododendron pigment in the retained lower layer liquid with a resin according to the embodiment of the present invention includes:

s401, washing the surface of the resin with clear water, draining after the resin is cleaned, and putting the resin into an elution tank.

S402, adding salt water with the mass fraction of 0/6-0.9% and the mass fraction of the salt water being equal to that of the resin into an elution tank, heating to 55-60 ℃, and carrying out primary elution.

And S403, performing secondary elution on the resin filtered out in the primary elution by using the primary eluent and an ethanol solution.

And S404, carrying out tertiary elution on the resin filtered out in the secondary elution by using the secondary eluent and the newly added ethanol solution to obtain the eluent.

The volume ratio of the resin to the ethanol solution provided by the embodiment of the invention is 1: 7-8, and the ethanol concentration is 40%.

The volume ratio of the resin to the ethanol solution provided by the embodiment of the invention is 1:3, and the ethanol concentration is 60%.

As shown in fig. 5, in step S106, performing ultrafiltration on the eluted solution to obtain an elution filtrate includes:

s501, adding purified water into the eluent for dilution, and filtering and sterilizing to obtain filtered feed liquid;

s502, concentrating the filtered feed liquid;

s503, keeping the volume of the feed liquid unchanged, and adding purified water in a flowing manner to wash and filter the feed liquid;

s504, after the purified water is washed and filtered, the feed liquid is washed and filtered by flowing sodium chloride solution, and then the elution filtrate is obtained.

In step S503, the amount of the purified water provided by the embodiment of the present invention is 7 to 9 times of the volume of the feed liquid.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and any modification, equivalent replacement, and improvement made by those skilled in the art within the technical scope of the present invention disclosed herein, which is within the spirit and principle of the present invention, should be covered by the present invention.