A method for extracting and purifying high-quality blueberry anthocyanins

Abstract

The present invention relates to a method for extracting and purifying high-quality blueberry anthocyanins, comprising thawing and coarse crushing, extraction, column chromatography and drying. The present invention adopts an acid aqueous solution as an extraction solvent and adopts a countercurrent extractor to perform continuous self-circulating spray-type percolation extraction, so that the extraction process is continuous and efficient. A composite resin layer is added to the bottom of a single chamber of countercurrent extraction, and while the extract is filtering fine impurities such as pomace and pectin cellulose, the metal ions therein can be effectively removed, and the pH environment of the solution can be stabilized, so that the blueberry anthocyanins are maintained at a high content, and the free anthocyanins are reduced to ≤0.5%, which is even lower than the standard requirement.

Description

Technical Field

[0001] The invention belongs to the field of natural pigment extraction, and particularly relates to a method for extracting and purifying high-quality blueberry anthocyanins. Background Art

[0002] Anthocyanidins, also known as flower pigments, are a class of water-soluble natural pigments widely found in plants in nature. Most of the main coloring substances in fruits, vegetables, and flowers are related to them. Under different pH conditions of plant cell vacuoles, anthocyanidins make the petals appear colorful. There are more than 20 known anthocyanidins, and there are 6 important ones in food, namely geranium pigment, cornflower pigment, delphinium pigment, peony pigment, morning glory pigment and mallow pigment.

[0003] Anthocyanins are a class of compounds formed by the combination of free anthocyanidins (2-benzopyran nucleus) and sugar groups through glycosidic bonds. They are widely present in the cell sap of flowers, fruits, stems, leaves and root organs of plants, making them appear in different colors from red, purple to blue. Anthocyanins are a family of compounds that can appear red in flavonoids, a class of substances based on flavonoid nuclei. Due to its unique functionality, it is used to remove free radicals in the body, proliferate lutein, fight tumors, fight cancer, fight inflammation, inhibit lipid peroxidation and platelet aggregation, prevent diabetes, lose weight, protect eyesight, etc. As a natural pigment, anthocyanins are safe, non-toxic, and have many health functions for the human body. They have been used in food, health products, cosmetics, medicine and other industries. Due to the unstable nature of anthocyanins, the glycosidic bonds of anthocyanins are easily broken in the solution state and degraded into free anthocyanidins.

[0004] In the group standard T / CCCMHPIE 1.25-2016 "Plant Extract Bilberry Extract" of the China Chamber of Commerce for Import and Export of Medicines and Health Products, the requirement for free anthocyanins is no more than 1.0%. It can be seen that for anthocyanin products, maintaining a low level of free anthocyanins is an important indicator of reaction quality.

[0005] The horizontal rotary continuous countercurrent extractor has the function of multi-stage (the number of times the same solid phase is leached) countercurrent extraction (meaning that the movement directions of the solid and liquid phases are opposite, and the solid material being leached is leached by the leaching liquid from the next stage in each stage of leaching operation. The fresh liquid phase solvent leaches the last stage of solid phase residue, and the most concentrated leaching liquid leaches the fresh solid phase material). The minimum amount of solvent can be used to maintain the driving force required for each stage of leaching, and the highest concentration of leaching liquid products can be obtained. Continuous countercurrent extraction has very excellent economic indicators in large-scale solid-liquid extraction operations.

[0006] MVR is the abbreviation of mechanical vapor recompression. It is an energy-saving technology that reuses the energy of the secondary steam generated by itself, thereby reducing the demand for external energy. Its working process is that the low-temperature steam is compressed by the compressor, the temperature and pressure are increased, the thermal enthalpy is increased, and then it enters the heat exchanger for condensation to make full use of the latent heat of the steam. Except for starting up, no steam is required during the entire evaporation process. The main features of the MVR evaporation system: energy saving; except for preheating, no steam is required during normal operation, reducing environmental pressure; no cooling system is required, saving cooling water; compared with multi-effect evaporation, the process is simple, the equipment is compact, and the footprint is small; compared with the traditional evaporation system, the heat exchange temperature difference is small and the heat exchange area is large; because the system is designed with a low temperature difference, the product evaporates gently, and the concentrated liquid is not easy to deteriorate or coke at high temperature.

[0007] CN101830950A provides a method for extracting anthocyanins from blueberries, including using blueberries as raw materials, crushing and adding pH 1-3 acidic water for soaking and extraction, clarifying the extract with a precipitant, adsorbing with a macroporous resin, eluting with a 70% ethanol solution, ultrafiltration of the eluate through an ultrafiltration membrane and then concentrating with a nanofiltration membrane, and spray drying the concentrate to obtain a finished product. It has the following disadvantages: 1. The acidic water soaking extraction takes a long time to extract, affecting the industrial production efficiency; 2. The extract is clarified by a precipitant, and taking the supernatant easily causes the effective components to be adsorbed by the precipitated solid, causing losses, and the precipitation process takes time, affecting the production continuity. Summary of the invention

[0008] The purpose of the present invention is to provide a method for extracting and purifying high-quality blueberry anthocyanins. By controlling the acidity of the extract and using a composite resin layer, the filtration step before column loading is saved, and the product has a lower content of free anthocyanins while maintaining a high content of anthocyanins.

[0009] The present invention provides a method for extracting and purifying high-quality blueberry anthocyanins, comprising the following steps:

[0010] (1) thawing and roughly chopping the frozen blueberry raw material, and then putting it into a countercurrent extractor, using an acid aqueous solution as an extraction solvent to perform room temperature or lukewarm extraction at 20° C. to 50° C.;

[0011] (2) The extraction solution obtained in the above step (1) is applied to a column for adsorption to enrich anthocyanins, washed with 2 to 3 column volumes of water to remove impurities, and analyzed with ethanol to obtain an analytical solution;

[0012] (3) The above analytical solution was concentrated under reduced pressure using an MVR concentrator, and the concentrated solution was spray-dried.

[0013] The countercurrent extractor in step (1) is a horizontally rotating continuous countercurrent extractor, and the number of circulating spray percolation extraction stages is 4 to 8.

[0014] In the countercurrent extractor in step (1), a composite resin layer of D001 cationic resin and CH-90Na chelating resin is laid on the sieve bottom of each single-stage extraction chamber, wherein the mass ratio of the two resins is 1:1.

[0015] The acid water in step (1) has a pH of 1.5-4.0 and is a hydrochloric acid aqueous solution.

[0016] The filler of the column in step (2) is a macroporous adsorption resin, preferably a non-polar to medium-polar resin such as DM21, XDA-6, AB-8, etc.

[0017] The concentration temperature of the MVR concentrator in step (3) is 40-60°C.

[0018] Beneficial Effects

[0019] The invention adopts an acid aqueous solution as an extraction solvent and adopts a countercurrent extractor to perform continuous self-circulating spray-type percolation extraction, so that the extraction process is continuous and efficient.

[0020] The composite resin layer paved on the bottom of a single chamber in countercurrent extraction can effectively remove metal ions from the extract while filtering out small impurities such as pomace and pectin cellulose, stabilize the pH environment of the solution, and thus well protect blueberry anthocyanins and reduce the production of free anthocyanins.

[0021] The extract does not need to be filtered to remove impurities, and can be directly enriched and purified on a resin column. The ethanol solution is concentrated at low temperature by an MVR concentrator, which effectively saves energy and reduces the degradation of anthocyanins. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the present application. Unless otherwise specified, the raw and auxiliary materials used in the following examples are materials available from commercial sources.

[0023] Example 1

[0024] 1. Thawing and coarse shredding: Transfer the frozen fresh fruits or fruit residues in the cold storage to the feeding room for thawing, generally within 12 hours. When the raw materials are not completely thawed, they can be coarsely shredded by a shredder before feeding.

[0025] 2. Extraction: A 3 cm thick composite resin layer of D001 cationic resin (purchased from Xi'an Lanxiao Technology New Materials Co., Ltd.) and CH-90Na chelating resin (Tulsimer brand resin, U.S.A.) in a mass ratio of 1:1 was laid on the sieve bottom of each single-stage extraction chamber, the horizontal countercurrent extractor was turned on, the feeding rate was set to 100 kg / h, the extraction solvent feeding rate was 2000 L / h, the extraction solvent temperature was kept at 20°C, the pH of the newly introduced extraction solvent acid water was adjusted to 1.5 with hydrochloric acid, and 4-stage countercurrent continuous circulation spray percolation extraction was performed to obtain an extract.

[0026] 3. Column chromatography

[0027] 3.1. Pretreatment: The above extract was applied to a DM21 macroporous resin adsorption column.

[0028] 3.2. Loading the column: The flow rate of the feed liquid is controlled at 0.5 times the column volume / h.

[0029] 3.3. Water washing: After the liquid is loaded onto the column, wash it with 2 times the column volume of drinking water, and control the flow rate to 0.5 times the column volume / h.

[0030] 3.4. Analysis: 1.5 column volumes of 55% ethanol were used for analysis, and the flow rate was controlled at 0.5 column volumes / h. The effluent that turned red and dark was collected.

[0031] 4. Concentration: Transfer the analyzed liquid to the MVR concentrator for vacuum concentration at 40°C until the discharge density reaches 14 degrees Baume.

[0032] 5. Spray drying: Take the concentrated solution, stir it evenly, and then spray dry it to obtain blueberry anthocyanin powder.

[0033] Example 2

[0034] 1. Thawing and coarse shredding: Transfer the frozen fresh fruits or fruit residues in the cold storage to the feeding room for thawing, generally within 12 hours. When the raw materials are not completely thawed, they can be coarsely shredded by a shredder before feeding.

[0035] 2. Extraction: A 3 cm thick composite resin layer of D001 cationic resin and CH-90Na chelating resin in a mass ratio of 1:1 was laid on the sieve bottom of each single-stage extraction chamber, the horizontal countercurrent extractor was turned on, the feeding rate was set to 200 kg / h, the extraction solvent feed rate was 3000 L / h, the extraction solvent temperature was kept at 35°C, the pH of the newly introduced extraction solvent was adjusted to 3.0 with acid water and hydrochloric acid, and 6-stage countercurrent continuous circulation spray percolation extraction was performed to obtain the extract.

[0036] 3. Column chromatography

[0037] 3.1. Pretreatment: The above extract was applied to XDA-6 macroporous resin adsorption column.

[0038] 3.2. Loading the column: The flow rate of the feed liquid is controlled at 1.0 times the column volume / h.

[0039] 3.3. Water washing: After the liquid is loaded onto the column, wash it with 2.5 times the column volume of drinking water, and control the flow rate to 1.0 times the column volume / h.

[0040] 3.4. Analysis: 2.0 column volumes of 58% ethanol were used for analysis, and the flow rate was controlled at 1.0 column volume / h. The effluent that turned red and dark was collected.

[0041] 4. Concentration: Transfer the analyzed liquid to the MVR concentrator for vacuum concentration at 50°C until the discharge density reaches 17 degrees Baume.

[0042] 5. Spray drying: Take the concentrated solution, stir it evenly, and then spray dry it to obtain blueberry anthocyanin powder.

[0043] Example 3

[0044] 1. Thawing and coarse shredding: Transfer the frozen fresh fruits or fruit residues in the cold storage to the feeding room for thawing, generally within 12 hours. When the raw materials are not completely thawed, they can be coarsely shredded by a shredder before feeding.

[0045] 2. Extraction: A 3 cm thick composite resin layer of D001 cationic resin and CH-90Na chelating resin in a mass ratio of 1:1 is laid on the sieve bottom of each single-stage extraction chamber, the horizontal countercurrent extractor is turned on, the feeding rate is set to 300 kg / h, the extraction solvent feed rate is 4000 L / h, the extraction solvent temperature is kept at 50°C, the pH of the newly introduced extraction solvent acid water is adjusted to 4.0 with hydrochloric acid, and 8-stage countercurrent continuous circulation spray percolation extraction is performed to obtain an extract.

[0046] 3. Column chromatography

[0047] 3.1. Pretreatment: The above extract was adsorbed on AB-8 macroporous resin column.

[0048] 3.2. Loading the column: The flow rate of the feed liquid is controlled at 2.0 times the column volume / h.

[0049] 3.3. Water washing: After the liquid is loaded onto the column, wash it with 3.0 times the column volume of drinking water, and control the flow rate to 2.0 times the column volume / h.

[0050] 3.4. Analysis: 2.5 column volumes of 60% ethanol were used for analysis, and the flow rate was controlled at 2.0 column volumes / h. The effluent that turned red and dark was collected.

[0051] 4. Concentration: Transfer the analytical solution to the MVR concentrator for vacuum concentration at 60°C until the discharge density reaches 20 degrees Baume.

[0052] 5. Spray drying: Take the concentrated solution, stir it evenly, and then spray dry it to obtain blueberry anthocyanin powder.

[0053] Comparative Example 1

[0054] Except that drinking water was used as the new solvent for extraction, the other operations were carried out according to steps 1 to 5 of Example 1 to obtain blueberry anthocyanin powder.

[0055] Comparative Example 2

[0056] Except that the sieve bottom of each single-stage extraction chamber of the horizontal countercurrent extractor is a metal sieve (without paving the composite resin layer of D001 cationic resin and CH-90Na chelating resin), the other operations are carried out according to steps 1 to 5 of Example 1 to obtain blueberry anthocyanin powder.

[0057] Comparative Example 3

[0058] Except that 65% ethanol was used as the new solvent for extraction and the pH was adjusted to 3.0 with hydrochloric acid, the other operations were carried out according to steps 1 to 5 of Example 1 to obtain blueberry anthocyanin powder.

[0059] Comparative Example 4

[0060] Step 2: acid water is used to adjust the pH to 1.5 with hydrochloric acid for soaking and extraction three times, the extraction time is 2 hours, 2 hours, and 2 hours, and the extract is filtered. The rest of the operations are carried out according to steps 1, 3, 4, and 5 of Example 1 to obtain blueberry anthocyanin powder.

[0061] Test data:

[0062] The obtained blueberry anthocyanin powder was tested for anthocyanin content and free anthocyanidin content according to the method of T / CCCMHPIE 1.25-2016A.2 and the results were compared. The standard stipulates that the anthocyanin content should be ≥36.0 and the free anthocyanidin content should be ≤1.0%.

[0063] Table 1 Comparison of anthocyanin content and free anthocyanidin content

[0064]

[0065]

[0066] As can be seen from Table 1, the blueberry anthocyanin powders prepared by purification in Examples 1 to 3 and Comparative Example 2 (acid aqueous solution as solvent) have higher anthocyanin content and lower free anthocyanidin content than Comparative Example 1 (drinking water as solvent), indicating that the acid aqueous solution has a protective effect on anthocyanins. Further comparison of Comparative Example 2 (acid aqueous solution as solvent, the extractor is not paved with a composite resin layer) and Examples 1 to 3 (acid aqueous solution as solvent) shows that the anthocyanin content is equivalent, but the free anthocyanidin content of Examples 1 to 3 is lower, indicating that the paving of the composite resin layer reduces the degradation of anthocyanins. Although the extraction effect of Comparative Example 3 (acidic ethanol solution as solvent) is also good, the use of ethanol obviously has a much higher production cost, low production safety, and the process economy is not as good as Examples 1 to 3.

Claims

1. A method for extracting and purifying high-quality blueberry anthocyanins, comprising the following steps: (1) thawing and roughly chopping the frozen blueberry raw material, and then putting it into a countercurrent extractor to extract it using an acid aqueous solution as an extraction solvent; wherein, The countercurrent extractor is provided with a composite resin layer of D001 cationic resin and CH-90Na chelating resin on the sieve bottom of each single-stage extraction chamber, and the mass ratio of the composite resin layer is 1:

1. (2) subjecting the extract obtained in step (1) to column adsorption to enrich anthocyanins, washing with water to remove impurities, and performing analysis with ethanol to obtain an analysis solution; (3) The above-mentioned analytical solution is concentrated under reduced pressure by an MVR concentrator, and the concentrated solution is spray-dried to obtain a high-quality anthocyanin product.

2. The method according to claim 1, characterized in that: The countercurrent extractor in step (1) is a horizontally rotating continuous countercurrent extractor, and the number of circulating spray percolation extraction stages is 4 to 8.

3. The method according to claim 1, characterized in that: The pH range of the acid aqueous solution in step (1) is 1.5-4.0, and it is a hydrochloric acid aqueous solution.

4. The method according to claim 1, characterized in that: The filler of the column in step (2) is a macroporous adsorption resin.

5. The method according to claim 1, characterized in that: The concentration temperature range of the MVR concentrator in step (3) is 40-60°C.

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