Method for purifying betacyanin through combined extraction-adsorption

Abstract

The invention relates to the technical field of betacyanin preparation, and discloses a method for purifying betacyanin through combined extraction-adsorption, which comprises the following steps: S1, pretreatment: peeling fresh pitaya without plant diseases and insect pests, and then cutting the peeled pitaya through numerical control cutting equipment, infrared spectrum equipment is used for detecting the moisture content of the pitaya and the initial content of betacyanin to form detection data, and the data is instantly transmitted to an intelligent control system through a wireless transmission module; s2, pre-extraction: putting the pretreated pitaya into an automatic stirrer; s3, extraction: the intelligent control system regulates the proportion of [BMIM] Cl, 1-butyl-3-methylimidazole chloride and water according to data detected by pretreatment. According to the method, the liquid formed by mixing [BMIM] Cl, 1-butyl-3-methylimidazole chloride and water is used in the extraction process, so that the problem that in the traditional extraction process, most solvents are water, ethanol and a mixed solution thereof, other impurities are possibly extracted, and consequently the purification difficulty is possibly increased is solved.

Description

Technical Field

[0001] The invention relates to the technical field of betalain preparation, in particular to a method for purifying betalain by combined extraction and adsorption. Background Art

[0002] Betalain is a type of natural pigment, mainly derived from plants such as red pitaya. It is a water-soluble nitrogen-containing pigment with its own unique chemical structure. It is composed of a chromophore and aglycone. This structure gives it a bright and unique color, which is commonly purple to dark purple. In terms of characteristics, betalain is relatively stable and can maintain its color within a certain temperature and pH range. However, its color will be reddish in a strong acidic environment and tend to be blue under alkaline conditions. This color change characteristic requires precise control of environmental factors when it is used in food coloring. In the food industry, betalain is very useful. Due to the increasing demand for natural pigments by consumers, it is widely used in candies, beverages, ice cream and other products as a natural substitute. It can not only give food an attractive coat, but also cater to the concept of health. In the field of medicine and health care, betalain also shows potential. Studies have found that it has antioxidant effects, can effectively remove free radicals in the body, slow down cell oxidative damage, and thus play a certain auxiliary role in preventing chronic diseases such as cardiovascular disease and cancer. At the same time, it also has anti-inflammatory properties, which can help reduce the body's inflammatory response. Moreover, the residue after extracting betalain from pitaya is rich in nutrients such as dietary fiber, and can be reused to develop functional foods, which fully reflects the multiple values ​​of betalain. Whether it is beautifying the appearance of food or promoting human health, it plays a unique role.

[0003] In the traditional extraction process, the solvents are mostly water, ethanol and their mixed solutions. These solvents are not ideal for the selective extraction of betalain and may extract many other impurities at the same time, such as sugars, proteins, etc., which may increase the difficulty of subsequent purification. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for combined extraction-adsorption purification of betalain, which solves the problem that the solvents in the traditional extraction process are mostly water, ethanol and their mixed solutions, and these solvents have less than ideal selective extraction ability for betalain, and may extract many other impurities at the same time, such as sugars, proteins, etc., which may increase the difficulty of subsequent purification.

[0005] To achieve the above objectives, the present invention is implemented by the following technical scheme: a method for purifying betalain by combined extraction-adsorption, comprising the following steps:

[0006] S1, peeling fresh, disease-free dragon fruit and cutting it with a CNC cutting device, using an infrared spectroscopy device to detect the moisture content and initial betalain content of the dragon fruit to form test data, and transmitting the data to an intelligent control system in real time through a wireless transmission module;

[0007] S2, pre-extraction: putting the pretreated pitaya into an automatic stirrer, and putting the pitaya together with the automatic stirrer into an intelligent ultrasonic microwave combined device for preliminary extraction;

[0008] S3, extraction: the intelligent control system prepares the ratio of [BM IM] C l, 1-butyl-3-methylimidazolium chloride and water according to the data of the pretreatment detection, prepares a mixed solvent through a magnetic stirrer, adds the mixed solvent into the pitaya stirrer after the preliminary extraction, and adjusts the intelligent ultrasonic microwave combined equipment to the pulse mode;

[0009] S4, filtration: after the extraction is completed, the extracted solution is poured into a filtration device to form an extract;

[0010] S5, adsorption purification: filling the molecular imprinting polymer and the macroporous resin into an adsorption column, and then passing the extract through the adsorption column;

[0011] S6. Elution: The betalain concentration at the outlet of the adsorption column is detected by an online betalain concentration monitor, and then the betalain in the adsorption column is eluted by an ethanol solution.

[0012] Preferably, in S1, the size of the pitaya is controlled to be between 2-5 cm by a numerically controlled cutting device.

[0013] Preferably, in S2, at 40-50° C., the ultrasonic power is controlled to be 200-300 W, the microwave power is controlled to be 300-400 W, and the agitator speed is controlled to be 50-150 rpm for 10-15 minutes.

[0014] Preferably, in S3, the mixed solvent is added to the agitator at a solid-liquid ratio of 1:10 g / ml, and the pulse mode is to adjust the ultrasonic power to 150-200 W, the microwave power to 200-300 W, and the ultrasound and microwave are turned on alternately every 2 minutes, and the extraction is continued for 20-30 minutes.

[0015] Preferably, the filtering device in S4 adopts a multi-layer composite filter membrane, and the multi-layer composite filter membrane is composed of a microfiltration membrane and an ultrafiltration membrane. The pore size of the microfiltration membrane is set to 0.5-1 micron, the pore size of the ultrafiltration membrane is 10-100 nanometers, and the filtration pressure is controlled at 0.1-0.3MPa.

[0016] Preferably, the molecular imprinting polymer in S5 is synthesized by precipitation polymerization using betalain as a template molecule, the modification of the boric acid group of the macroporous resin is carried out by chemical grafting, and the modification density is precisely controlled at 3-5 boric acid groups per square nanometer. A polystyrene-divinylbenzene macroporous resin is selected as the matrix, and the model is HPD-100. The molecular imprinting polymer and the macroporous resin are mixed in a ratio of 2:1 to fill the adsorption column. The adsorption column is made of stainless steel, and the inner wall is polished and inert coating treated. The temperature of the adsorption column is controlled at 25-30°C, and the flow rate of the extract through the adsorption column is controlled at 2-3BV / h.

[0017] Preferably, the concentration of the ethanol solution in S6 is controlled at 70-80%, and the elution flow rate is controlled at 1-2 BV / h.

[0018] Preferably, after the elution is completed, the adsorption column is regenerated by nitrogen purging combined with 40-50° C. hot air drying, the flow rate of the nitrogen purging is 5-10 L / min, and the regeneration time is controlled at 30-45 minutes.

[0019] The present invention provides a method for purifying betalain by combined extraction and adsorption. It has the following beneficial effects:

[0020] 1. In the present invention, by using [BMIM]C l in the extraction process, the liquid mixed with 1-butyl-3-methylimidazolium chloride and water can have better selectivity for betalain in pitaya, [BMIM]C l can form hydrogen bonds with the hydroxyl and carbonyl groups in the betalain molecule, and has weak interaction with other components in pitaya, thereby reducing the dissolution of impurities, thereby improving the traditional extraction process in which the solvents are mostly water and ethanol and their mixed solutions, and these solvents have unsatisfactory selective extraction ability for betalain, and may simultaneously extract many other impurities, such as sugars, proteins, etc., which may increase the difficulty of subsequent purification.

[0021] 2. In the present invention, by accurately cutting the pitaya pieces into 2-5 cm in the pretreatment stage, it can be ensured that the material is heated and the mass transfer is uniform during the subsequent extraction. During the pre-extraction, 40-50°C is combined with ultrasound, microwave and stirring, and ultrasonic cavitation and microwave thermal effects are used to initially destroy the cells, so that a large amount of betalain is dissolved; the process is further enhanced by pulse mode extraction, and the periodic alternating energy input continuously breaks the cells, allowing the betalain to be released more fully, thereby improving the extraction rate of betalain from the pitaya raw material.

[0022] 3. In the present invention, a multi-layer composite filter membrane is used, a microfiltration membrane removes larger solid impurities, an ultrafiltration membrane intercepts small molecular impurities, and fine filtration ensures that the extract entering the adsorption purification step has very few impurities. During adsorption purification, the molecular imprinting polymer has a synergistic effect on the specific adsorption of betalain and the broad-spectrum adsorption of the macroporous resin, accurately captures betalain and removes impurities such as sugars and proteins. At the same time, the temperature and flow rate of the adsorption column are accurately controlled to ensure the high efficiency of the adsorption process, thereby improving the purity of the betalain.

[0023] 4. In the present invention, the intelligent control system is used to allocate the solvent according to the preliminary detection data. The precise material-liquid ratio ensures the extraction effect and avoids solvent waste. Moreover, the ethanol in the waste liquid of the adsorption column elution can be recycled after treatment, and the recovery rate is not less than 80%, which reduces the consumption of ethanol as an organic solvent and reduces the cost of raw materials.

[0024] 5. In the present invention, through infrared spectrum detection and wireless data transmission during raw material pretreatment, to multi-parameter precise control of intelligent ultrasonic microwave equipment during pre-extraction and extraction, through automatic switching and parameter adjustment of each link of adsorption purification and elution regeneration based on real-time monitoring data, a high degree of automation is achieved throughout the process. Through strict parameter limitations in each link, such as the adsorption column temperature is accurately set at 25-30°C and the elution flow rate is 1-2BV / h, each step of operation is ensured to be stable and efficient, human errors are reduced, thereby improving the quality stability and production efficiency of betalain. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. 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.

[0027] Please refer to the attached Figure 1 The embodiment of the present invention provides a method for purifying betalain by combined extraction and adsorption, comprising the following steps:

[0028] S1. Pretreatment: peel the fresh dragon fruit without disease and insect pests and cut it by CNC cutting equipment, use infrared spectroscopy equipment to detect the moisture content and initial betalain content of the dragon fruit to form test data, and transmit the data to the intelligent control system in real time through a wireless transmission module;

[0029] S2, pre-extraction: putting the pretreated pitaya into an automatic stirrer, and putting the pitaya together with the automatic stirrer into an intelligent ultrasonic microwave combined device for preliminary extraction;

[0030] S3, extraction: the intelligent control system prepares the ratio of [BM IM] C l, 1-butyl-3-methylimidazolium chloride and water according to the data of the pretreatment detection, prepares a mixed solvent through a magnetic stirrer, adds the mixed solvent into the pitaya stirrer after the preliminary extraction, and adjusts the intelligent ultrasonic microwave combined equipment to the pulse mode;

[0031] S4, filtration: after the extraction is completed, the extracted solution is poured into a filtration device to form an extract;

[0032] S5, adsorption purification: filling the molecular imprinting polymer and the macroporous resin into an adsorption column, and then passing the extract through the adsorption column;

[0033] S6. Elution: The betalain concentration at the outlet of the adsorption column is detected by an online betalain concentration monitor, and then the betalain in the adsorption column is eluted by an ethanol solution.

[0034] Specifically, a highly sensitive online betalain concentration monitor is installed at the outlet of the adsorption column to monitor the betalain concentration in the effluent in real time.

[0035] By using infrared spectroscopy equipment to detect the moisture content and initial betalain content of pitaya, the detection data can be intelligently adjusted according to the moisture content, and the ultrasonic power, microwave power, extraction time and other parameters can be intelligently adjusted according to the initial content of betalain.

[0036] In S6, when the concentration at the outlet of the adsorption column rises to 0.1 mg / ml, indicating that the adsorption is close to saturation, the control system automatically switches the elution process.

[0037] The whole process is carried out in an integrated device. The device adopts a modular design concept, integrating pretreatment, pre-extraction, extraction, filtration, adsorption purification and elution functions in a stainless steel frame. The modules are seamlessly connected through food-grade silicone pipes and intelligent electric valve systems. The filtered solution enters the adsorption purification device directly through the pipeline. After the adsorption purification is saturated, the outflow of the extract is stopped immediately, and then the adsorption column is eluted. When the adsorption column is regenerated, the extraction liquid pipeline can be opened to continue adsorption, thereby avoiding the transfer of materials between relative steps, and only the corresponding pipeline needs to be stopped. Buffer tanks are set at key nodes of the equipment to ensure the stability of material flow and avoid the impact of flow rate fluctuations on the process. The control system is equipped with advanced artificial intelligence algorithms, which automatically adjust key operating parameters such as ultrasonic power, microwave power, solvent flow, adsorption flow rate, etc. according to preset process parameters and real-time monitoring data. At the same time, the control system has data storage and analysis functions, and can record data of at least 100 continuous production processes to facilitate subsequent process optimization and quality traceability. The control accuracy of the control system should meet the requirements that the ultrasonic power error is within ±10W, the microwave power error is within ±20W, the solvent flow error is within ±0.1BV / h, and the adsorption flow rate error is within ±0.05BV / h.

[0038] In S1, the size of the dragon fruit is controlled between 2-5 cm by CNC cutting equipment.

[0039] Specifically, by controlling the size of pitaya to between 2-5 cm, it can ensure that the material is heated and mass transferred evenly during subsequent extraction, thereby improving the extraction efficiency and quality of betalain.

[0040] In S2, at 40-50° C., the ultrasonic power is controlled to be 200-300 W, the microwave power is controlled to be 300-400 W, and the stirrer speed is controlled to be 50-150 rpm for 10-15 minutes.

[0041] Specifically, by keeping the temperature at 40-50°C, the destruction of betalain due to excessively high temperature can be avoided, thereby ensuring its chemical structure and biological activity, and facilitating the subsequent acquisition of high-quality betalain products. By utilizing the cavitation effect of ultrasound and the rapid heating of microwaves, with the assistance of appropriate temperature and stirring, the cell structure of pitaya can be initially destroyed, promoting the dissolution of betalain, thereby effectively starting the pre-extraction process of betalain.

[0042] In S3, the mixed solvent is added into the stirrer at a material-liquid ratio of 1:10 g / ml. The pulse mode is to adjust the ultrasonic power to 150-200 W and the microwave power to 200-300 W. The ultrasonic and microwave are turned on alternately every 2 minutes, and the extraction is continued for 20-30 minutes.

[0043] Specifically, a periodic energy input can be generated through the pulse mode. The cavitation effect of ultrasound can produce tiny bubbles in the solvent. These bubbles will generate a strong impact when they burst, which helps to further destroy the cell structure of pitaya. Microwave heating can intensify the movement of betalain molecules in cells. This alternating method can continuously destroy cells from different angles and mechanisms, so that betalain is more fully released into the solvent, strengthening the extraction process. At the same time, it avoids the continuous accumulation of energy and gives the system a short "buffer" time, so that while effectively extracting, it can reduce the potential damage to betalain and the solvent system caused by excessive energy input. The pulse mode will cause changes in convection and diffusion movement of solutes inside the solvent. The alternating ultrasound and microwave effects make the interaction between the solvent and the solute more complex and dynamic, which helps to improve the solubility of betalain in the solvent, making it more evenly dispersed in the solvent, and further improving the extraction effect.

[0044] The filtration device in S4 adopts a multi-layer composite filter membrane, which is composed of a microfiltration membrane and an ultrafiltration membrane. The pore size of the microfiltration membrane is set to 0.5-1 microns, the pore size of the ultrafiltration membrane is 10-100 nanometers, and the filtration pressure is controlled at 0.1-0.3MPa.

[0045] Specifically, by setting the pore size of the microfiltration membrane to 0.5-1 micron, larger solid particles such as undissolved cellulose fragments, pitaya tissue residues, etc. can be effectively retained. By setting the pore size of the ultrafiltration membrane to 10-100 nanometers, small molecular impurities such as pectin and protein can be further removed. In this way, the extract can be finely filtered to remove impurities of various particle sizes, greatly improving the purity of the extract. Filtration can prevent solid impurities from entering the subsequent adsorption and purification steps. The use of a multi-layer composite filter membrane can effectively reduce the impact of impurities on the quality of the final betalain product. Unfiltered impurities may be adsorbed or chemically reacted with betalain in the subsequent process. Fine filtration through a multi-layer composite filter membrane can eliminate these potential interference factors, which helps to stably obtain high-purity betalain products.

[0046] The molecular imprinting polymer in S5 is synthesized by precipitation polymerization with betalain as the template molecule. The modification of the boric acid group of the macroporous resin is carried out by chemical grafting, and the modification density is precisely controlled at 3-5 boric acid groups per square nanometer. Polystyrene-divinylbenzene macroporous resin is selected as the matrix, model HPD-100. The molecular imprinting polymer and the macroporous resin are mixed in a ratio of 2:1 to fill the adsorption column. The adsorption column is made of stainless steel, and the inner wall is polished and inert coating treated. The temperature of the adsorption column is controlled at 25-30°C, and the flow rate of the extract through the adsorption column is controlled at 2-3BV / h.

[0047] Specifically, molecular simulation technology is used to optimize the types and amounts of monomers, cross-linking agents, and ensure that the imprinted polymer has highly specific adsorption sites for betalain. The inner wall of the adsorption column is polished and treated with an inert coating to prevent pigment adsorption. The high selectivity of molecularly imprinted polymers and the broad-spectrum adsorption characteristics of macroporous resins are used to accurately adsorb betalain and remove most impurities.

[0048] The concentration of the ethanol solution in S6 is controlled at 70-80%, and the elution flow rate is controlled at 1-2 BV / h.

[0049] Specifically, the elution flow rate can be controlled at 1-2BV / h. The waste liquid generated during the elution process is recycled into ethanol through a waste liquid treatment system. The waste liquid treatment system uses a distillation tower combined with molecular sieve adsorption technology to ensure that the ethanol recovery efficiency is not less than 80%. The recovered ethanol can be directly reused in the elution process after the online purity test meets the reuse standard.

[0050] After the adsorption column is eluted, it is regenerated by nitrogen purging combined with 40-50°C hot air drying. The flow rate of nitrogen purging is 5-10L / min, and the regeneration time is controlled at 30-45 minutes.

[0051] Specifically, the adsorption column can be quickly reused through regeneration.

[0052] 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 purifying betalain by combined extraction-adsorption, characterized in that: The following steps are involved: S1. Pretreatment: peel the fresh dragon fruit without disease and insect pests and cut it by CNC cutting equipment, use infrared spectroscopy equipment to detect the moisture content and initial betalain content of the dragon fruit to form test data, and transmit the data to the intelligent control system in real time through a wireless transmission module; S2, pre-extraction: putting the pretreated pitaya into an automatic stirrer, and putting the pitaya together with the automatic stirrer into an intelligent ultrasonic microwave combined device for preliminary extraction; S3, extraction: the intelligent control system prepares the ratio of [BMIM]Cl, 1-butyl-3-methylimidazolium chloride and water according to the data of the pretreatment test, makes a mixed solvent through a magnetic stirrer, adds the mixed solvent into the pitaya stirrer after the preliminary extraction, and adjusts the intelligent ultrasonic microwave combined equipment to the pulse mode; S4, filtration: after the extraction is completed, the extracted solution is poured into a filtration device to form an extract; S5, adsorption purification: filling the molecular imprinting polymer and the macroporous resin into an adsorption column, and then passing the extract through the adsorption column; S6. Elution: The betalain concentration at the outlet of the adsorption column is detected by an online betalain concentration monitor, and then the betalain in the adsorption column is eluted by an ethanol solution.

2. The method for purifying betalain by combined extraction-adsorption according to claim 1, characterized in that: In the S1, the size of the dragon fruit is controlled between 2 and 5 cm by a numerically controlled cutting device.

3. The method for purifying betalain by combined extraction and adsorption according to claim 1, characterized in that: In the S2, at 40-50° C., the ultrasonic power is controlled to be 200-300 W, the microwave power is controlled to be 300-400 W, and the stirrer speed is controlled to be 50-150 rpm for 10-15 minutes.

4. The method for purifying betalain by combined extraction-adsorption according to claim 1, characterized in that: In S3, the mixed solvent is added into the stirrer at a material-liquid ratio of 1:10 g / ml. The pulse mode is to adjust the ultrasonic power to 150-200 W and the microwave power to 200-300 W. Ultrasound and microwave are turned on alternately every 2 minutes, and the extraction is continued for 20-30 minutes.

5. The method for purifying betalain by combined extraction and adsorption according to claim 1, characterized in that: The filtering device in S4 adopts a multi-layer composite filter membrane, which is composed of a microfiltration membrane and an ultrafiltration membrane. The pore size of the microfiltration membrane is set to 0.5-1 micron, the pore size of the ultrafiltration membrane is 10-100 nanometers, and the filtration pressure is controlled at 0.1-0.3MPa.

6. The method for purifying betalain by combined extraction and adsorption according to claim 1, characterized in that: The molecular imprinting polymer in S5 is synthesized by precipitation polymerization with betalain as the template molecule. The modification of the boric acid group of the macroporous resin is carried out by chemical grafting, and the modification density is precisely controlled to be 3-5 boric acid groups per square nanometer. Polystyrene-divinylbenzene macroporous resin is selected as the matrix, and the model is HPD-100. The molecular imprinting polymer and the macroporous resin are mixed in a ratio of 2:1 to fill the adsorption column. The adsorption column is made of stainless steel, and the inner wall is polished and inert coating treated. The temperature of the adsorption column is controlled at 25-30°C, and the flow rate of the extract through the adsorption column is controlled at 2-3BV / h.

7. The method for purifying betalain by combined extraction and adsorption according to claim 1, characterized in that: The concentration of the ethanol solution in the S6 is controlled at 70-80%, and the elution flow rate is controlled at 1-2 BV / h.

8. The method for purifying betalain by combined extraction-adsorption according to claim 1, characterized in that: After the adsorption column is eluted, it is regenerated by nitrogen purging combined with 40-50° C. hot air drying. The flow rate of the nitrogen purging is 5-10 L / min, and the regeneration time is controlled at 30-45 minutes.

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