Method for extracting perilla leaf anthocyanin by using ternary eutectic solvent
阅读说明：本技术 一种利用三元低共熔溶剂提取紫苏叶花青素的方法 (Method for extracting perilla leaf anthocyanin by using ternary eutectic solvent ) 是由 韩晓祥 叶青 杜银霜 丰艺璇 郑丽娜 汪思田 徐艺洺 王彦波 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种紫苏叶花青素提取方法,具体涉及低共熔溶剂的制备及其在超声波-微波-紫外光的协助下提取花青素方法。该低共熔溶剂具有结构多样、可生物降解、环保、易制备、能再生、低熔点等优点,是一种绿色溶剂,较少剂量的加入,可有效的减少溶剂的损耗,能较明显的增加花青素的含量；且利用超声波-微波-紫外光联用可以互补单波缺点,是一门集超声波和微波提取优点为一体的新兴技术,使溶剂更容易穿过植物基质,使有效成分更易溶于溶剂中。(The invention discloses a method for extracting anthocyanin from perilla leaves, and particularly relates to a preparation method of a eutectic solvent and a method for extracting the anthocyanin from the eutectic solvent under the assistance of ultrasonic waves, microwaves and ultraviolet light. The eutectic solvent has the advantages of various structures, biodegradability, environmental protection, easy preparation, regeneration, low melting point and the like, is a green solvent, can effectively reduce the loss of the solvent by adding a small amount of solvent, and can obviously increase the content of anthocyanin; the method utilizes the combination of ultrasonic wave-microwave-ultraviolet light to complement the single-wave defect, is a novel technology integrating the advantages of ultrasonic wave and microwave extraction, enables the solvent to penetrate through the plant matrix more easily, and enables the effective components to be dissolved in the solvent more easily.)
1. A method for extracting perilla leaf anthocyanin by using a ternary eutectic solvent is characterized by comprising the following steps:
(1) taking polyhydric alcohol as a hydrogen bond donor, taking sugar or carboxylic acid as an auxiliary ligand, mixing the hydrogen bond donor and a hydrogen bond acceptor choline chloride (ChCl) according to a molar ratio of 2-6: 1, then adding the auxiliary ligand for mixing, wherein the molar ratio of the auxiliary ligand to the choline chloride is 0.1-1: 1, and adding N2Heating and stirring the mixture to react in an atmosphere and under the condition of oil bath, and obtaining a clear ternary eutectic solvent DES after the reaction is finished;
(2) preparing a mixed eutectic extracting solution from a ternary eutectic solvent DES and distilled water, wherein the volume fraction of the ternary eutectic solvent DES is 50-90%;
(3) the method comprises the following steps of (1) extracting anthocyanin from perilla leaf powder serving as a raw material to obtain an anthocyanin extracting solution, wherein the anthocyanin extracting solution specifically comprises the following steps: taking the mixed eutectic extracting solution as an extracting solvent, mixing perilla leaf powder and the mixed eutectic extracting solution according to a mass-volume ratio (g/ml) of 1: 4-12, and extracting anthocyanin of the perilla leaf powder under the synergistic effect of an ultrasonic-microwave-ultraviolet combined extraction instrument to obtain the anthocyanin extracting solution; wherein the temperature of the ultrasonic-microwave-ultraviolet combined extraction instrument is 40-80 ℃, the microwave power is 300-500W, the ultrasonic power is 300-500W, and the action time is 10-30 min; the intensity of the ultraviolet light was 10. mu.W/cm2；
(4) Centrifuging the obtained anthocyanin extract at 9000r/min at 4 deg.C for 10min, filtering with 0.22um porous membrane to obtain filtrate, and freeze drying the filtrate in a freeze drying instrument at-60 deg.C for 24 hr to obtain powdered anthocyanin.
2. The method for preparing the eutectic melting solvent according to claim 1, wherein the polyol in the step (1) may be ethylene glycol, glycerol; the sugar can be fructose, glucose, or sucrose; the carboxylic acid can be oxalic acid, lactic acid, citric acid.
3. The method for preparing the eutectic melting solvent according to claim 2, wherein the polyhydric alcohol is preferably ethylene glycol; the sugar is preferably glucose; the carboxylic acid is preferably lactic acid.
4. The preparation process according to claim 1, wherein the molar ratio of the hydrogen bond donor to choline chloride in step (1) is preferably 3: 1; the molar ratio of ancillary ligand to choline chloride is preferably 0.7: 1.
5. The process according to claim 1, wherein the reaction conditions of the oil bath in the step (1) are a heating temperature of 90 ℃ and a heating time of 1 hour.
6. The preparation method according to claim 1, wherein the volume fraction of the multi-component eutectic solvent DES in the step (2) is preferably 80%.
7. The extraction method according to claim 1, wherein the mass-to-volume ratio (g/ml) of the perilla leaf powder to the mixed eutectic solvent in the step (3) is preferably 1: 10.
8. The extraction method according to claim 1, wherein the temperature of the ultrasonic-microwave-ultraviolet combined extractor in the step (3) is preferably 60 ℃; the microwave power is preferably 400W; the ultrasonic power is preferably 400W; the action time is preferably 25 min.
Technical Field
The invention relates to the technical field of plant extraction, and particularly relates to a method for extracting perilla leaf anthocyanin by using a ternary eutectic solvent.
Background
With the development of science and technology and the improvement of living standard, the demand of a novel green solvent and equipment for extracting natural macromolecular products is increasing day by day.
The eutectic solvent (DES) belongs to an ion-like solution, has the advantages of various structures, biodegradability, environmental protection, easy preparation, regeneration, low melting point and the like, is a green solvent, the freezing point of the eutectic solvent is mostly-38-150 ℃, and compared with the melting points of hydrogen bond donor substances and hydrogen bond acceptor substances which form the eutectic solvent, the freezing point of the eutectic solvent can be usually reduced by 20-120 ℃. Therefore, the catalyst has wide application in various fields including catalytic reaction, extraction separation, CO2And SO2Trapping, material preparation, etc. By selecting different hydrogen bond acceptors and hydrogen bond donors and matching with combination in different proportions, the physicochemical properties of the eutectic solvent can be adjusted.
Perilla frutescens (L.) Britton is a medicinal and edible plant of Labiatae (Labiatae). The perilla leaf contains anthocyanidin and perianin, the volatile oil mainly comprises perillaldehyde, rosmarinic acid and other bioactive substances, and has the functions of resisting bacteria and diminishing inflammation, preventing allergy, clearing heat, resisting oxidation and the like.
Anthocyanins (Anthocynin) in folium Perillae is a powerful antioxidant, protects organism from free radical attack, is a water soluble natural pigment widely present in plants, and belongs to flavonoid compounds. The basic structure of anthocyanins is a 2-phenylbenzopyran type cation, i.e. an anthocyanidin. Different color structures appear in different pH environments, and the pH value is in alkaline solution>11 is blue under the condition, can stably exist under the condition that the pH value of the red solution is 1-3 in an acid solution, and is neutralThe solution is purple under the condition that the pH value of the solution is 7-8, and the solution has three carbon atoms C in two benzene rings6-C3-C6The substituents on the nucleus are different and related to the environment, have a 3,5, 7-trihydroxy-2-phenyl benzopyran cationic structure, are water-soluble natural edible pigments, are easily soluble in polar solvents such as methanol, ethanol, acetone and the like, are easily subjected to light (the reason may be that under the light condition, anthocyanin is degraded to generate chalcone, chalcone is rapidly degraded to generate products such as benzoic acid and the like, the presence of oxygen in the air can accelerate the generation of degradation reaction, at high temperature, anthocyanin is favorably converted into cationic diphenyl benzopyran, and the chalcone is favorably and rapidly formed), pH and temperature are influenced, more than 20 kinds of anthocyanin are known, and pelargonium pigment, cyanidin, delphinium pigment, paeoniflorin, petunia pigment and mallow pigment mainly exist in plants.
The microwave auxiliary extraction method is a method of adding physical field, and its principle is that the magnetron generates 24.5 hundred million times/s ultrahigh frequency quick vibration to make the molecules in the material mutually collide and extrude, so that it is favourable for leaching out effective component. Has the characteristics of high selectivity, short operation time, low solvent consumption, high yield of effective components, suitability for thermally unstable substances and the like. However, there are problems such as the remaining of organic solvent and attenuation of microwaves when they penetrate the inside of the material. The ultrasonic-assisted extraction method utilizes strong vibration, high acceleration, strong cavitation effect, stirring effect and the like generated by ultrasonic waves to cause the impact of micro-jet, can accelerate the effective components in the plants to enter a solvent to generate in liquid (cavitation effect), destroys plant cells and membrane structures, and is beneficial to the diffusion of solutes, thereby increasing the extraction rate of the effective components, shortening the extraction time and avoiding the influence of high temperature on the extracted components. Zhanglunpei et al research on ultrasonic-assisted extraction of flavonoids from stems and leaves of Douglas fir, obtained by optimal extraction process with ethanol concentration of 70%, material-liquid ratio of 1:20, ultrasonic power of 350W, extraction temperature of 60 deg.C, and extraction time of 30 min. Therefore, the anthocyanin in the perilla leaves is extracted by using an ultraviolet-microwave-ultrasonic combined extractor in cooperation with the eutectic solvent.
Disclosure of Invention
The invention aims to provide an anthocyanin extraction method aiming at the defects of the prior art, and particularly relates to a preparation method of a ternary eutectic solvent and a method for extracting perilla leaf anthocyanin by the aid of an ultrasonic-microwave-ultraviolet combined extraction instrument. The eutectic solvent has the advantages of various structures, biodegradability, environmental protection, easy preparation, regeneration, low melting point and the like, is a novel green solvent, has greatly reduced consumption of hydrogen bond donor glycol and high utilization efficiency compared with other binary eutectic solvents, and greatly increases the extraction content of anthocyanin by combining structural analysis of a target extraction component anthocyanin and adding an auxiliary ligand lactic acid; the method has the advantages that the defects can be complemented by utilizing the combination of ultrasonic wave-microwave-ultraviolet light, and the method is a novel technology integrating the advantages of ultrasonic wave and microwave extraction, so that the solvent can more easily penetrate through the plant matrix, and the effective components can be more easily dissolved in the solvent. The synergistic extraction method has the advantages of simple required equipment, simple and convenient process and mild action condition, and provides some identification for subsequent high-valued products.
The purpose of the invention is realized by the following technical scheme: a method for extracting perilla leaf anthocyanin by using a ternary eutectic solvent comprises the following steps:
(1) taking polyhydric alcohol as a hydrogen bond donor, taking sugar or carboxylic acid as an auxiliary ligand, mixing the hydrogen bond donor and a hydrogen bond acceptor choline chloride (ChCl) according to a molar ratio of 2-6: 1, then adding the auxiliary ligand for mixing, wherein the molar ratio of the auxiliary ligand to the choline chloride is 0.1-1: 1, and adding N2Heating and stirring the mixture to react in an atmosphere and under the condition of oil bath, and obtaining a clear ternary eutectic solvent DES after the reaction is finished;
(2) preparing a mixed eutectic extracting solution from a ternary eutectic solvent DES and distilled water, wherein the volume fraction of the ternary eutectic solvent DES is 50-90%;
(3) the method comprises the following steps of (1) extracting anthocyanin from perilla leaf powder serving as a raw material to obtain an anthocyanin extracting solution, wherein the anthocyanin extracting solution specifically comprises the following steps: taking the mixed eutectic extracting solution as an extracting solvent, mixing perilla leaf powder and the mixed eutectic extracting solution according to the mass-volume ratio (g/ml) of 1: 4-12, and extracting the cyanine thereof under the synergistic action of an ultrasonic-microwave-ultraviolet combined extractorObtaining anthocyanin extract; wherein the temperature of the ultrasonic-microwave-ultraviolet combined extraction instrument is 40-80 ℃, the microwave power is 300-500W, the ultrasonic power is 300-500W, and the action time is 10-30 min; the intensity of the ultraviolet light was 10. mu.W/cm2；
(4) Centrifuging the obtained anthocyanin extract at 9000r/min at 4 deg.C for 10min, filtering with 0.22um porous membrane to obtain filtrate, and freeze drying the filtrate in a freeze drying apparatus at-60 deg.C for 24 hr to obtain powdered anthocyanin.
Further, the polyhydric alcohol in the step (1) can be ethylene glycol or glycerol; the sugar can be fructose, glucose, or sucrose; the carboxylic acid can be oxalic acid, lactic acid, citric acid.
Further, the polyhydric alcohol is preferably ethylene glycol; the sugar is preferably glucose; the carboxylic acid is preferably lactic acid.
Further, the molar ratio of the hydrogen bond donor to the choline chloride in the step (1) is preferably 3: 1; the molar ratio of ancillary ligand to choline chloride is preferably 0.7: 1.
Further, the oil bath reaction condition in the step (1) is that the heating temperature is 90 ℃ and the time is 1 h.
Further, the volume fraction of the multi-component eutectic solvent DES in step (2) is preferably 80%.
Further, the mass volume ratio (g/ml) of the perilla leaf powder to the mixed eutectic solvent in the step (3) is preferably 1: 10.
Further, the temperature of the ultrasonic-microwave-ultraviolet combined extractor in the step (3) is preferably 60 ℃; the microwave power is preferably 400W; the ultrasonic power is preferably 400W; the action time is preferably 25 min.
Compared with the prior art, the invention has the following beneficial effects:
the method takes the ternary eutectic solvent as the extractant to extract the anthocyanin in the perilla leaves under the assistance of the ultrasonic-microwave-ultraviolet combined extractor, so that the method not only has better extraction capability, but also is a novel environment-friendly green solvent with low steam pressure and reproducibility, can effectively reduce the loss of the solvent for the addition of a small amount of hydrogen bond donor and auxiliary ligand, and can obviously increase the content of the anthocyanin under the mild process condition; compared with the existing literature, the ultrasonic wave-microwave-ultraviolet light combined extraction instrument has the advantages that the ultrasonic wave-microwave-ultraviolet light combined extraction instrument can effectively make up for the defects of single wave under the ultraviolet atmosphere by combining the ultrasonic wave and the microwave, is a novel technology integrating the advantages of ultrasonic wave and microwave extraction, and can greatly increase the extraction rate of anthocyanin.
Drawings
FIG. 1 is a block flow diagram of the present invention;
FIG. 2 is an infrared characterization diagram of eutectic software.
Detailed Description
In order to better illustrate the technical solution of the present invention, the present invention is further illustrated in detail with reference to the following examples.
As shown in fig. 1, the method for extracting perilla leaf anthocyanin by using ternary eutectic solvent provided by the invention comprises the following steps:
(1) using polyalcohol as hydrogen bond donor, sugar or carboxylic acid as auxiliary ligand, wherein the polyalcohol can be ethylene glycol or glycerol, preferably ethylene glycol; the sugar can be fructose, glucose, sucrose, preferably glucose; the carboxylic acid can be oxalic acid, lactic acid, citric acid, preferably lactic acid. Mixing a hydrogen bond donor and a hydrogen bond acceptor choline chloride (ChCl) according to a molar ratio of 2-6: 1, preferably 3:1, then adding an auxiliary ligand for mixing, wherein the molar ratio of the auxiliary ligand to the choline chloride is 0.1-1: 1, preferably 0.7:1, and adding N2Heating and stirring to react in the atmosphere and under the condition of oil bath, wherein the oil bath reaction condition is that the heating temperature is 90 ℃ and the time is 1h, and after the reaction is finished, a clear ternary eutectic solvent DES can be obtained;
(2) preparing a mixed eutectic extracting solution from a ternary eutectic solvent DES and distilled water, wherein the volume fraction of the ternary eutectic solvent DES is 50-90%, and the preferred volume fraction is 80%;
(3) the method comprises the following steps of (1) extracting anthocyanin from perilla leaf powder serving as a raw material to obtain an anthocyanin extracting solution, wherein the anthocyanin extracting solution specifically comprises the following steps: taking the mixed eutectic extracting solution as an extracting solvent, mixing perilla leaf powder and the mixed eutectic extracting solution according to a mass-volume ratio (g/ml) of 1:4-12, preferably 1:10, and extracting anthocyanin of the plant under the synergistic effect of an ultrasonic-microwave-ultraviolet combined extractor to obtain an anthocyanin extracting solution; wherein the temperature of the ultrasonic-microwave-ultraviolet combined extraction instrument is 40-80 ℃, the microwave power is 300-500W, the ultrasonic power is 300-500W, and the action time is 10-30 min; the intensity of the ultraviolet light was 10. mu.W/cm2(ii) a The temperature of the ultrasonic-microwave-ultraviolet combined extraction instrument is preferably 60 ℃; the microwave power is preferably 400W; the ultrasonic power is preferably 400W; the action time is preferably 25 min.
(4) Centrifuging the obtained anthocyanin extracting solution at the rotating speed of 9000r/min at the temperature of 4 ℃ for 10min, filtering the anthocyanin extracting solution by a 0.22-micron porous filter membrane to obtain filtrate, freeze-drying the filtrate in a freeze-drying instrument at the temperature of-60 ℃ for 24h to obtain powdery anthocyanin, forming a composite natural preservative film by the powdery anthocyanin and substances such as chitosan and the like which are easy to form a film, and approximately evaluating the putrefaction of the substances such as aquatic products and the like in a sense by the color change of the anthocyanin along with PH.
As can be seen from FIG. 2, the infrared characterization trends of EG, ChCl-3 EG and ChCl-3 EG-0.7LA are basically the same, that is, the transition of the vibration energy level and the rotation energy level in the molecule is not obviously changed, which indicates that the eutectic solvent system obtained after mixing ethylene glycol, choline chloride and lactic acid is not chemically changed, the characteristic structures of all components are not destroyed, and the eutectic solvent system is eutectic through the interaction of hydrogen bonds to form a homogeneous solution.
As can be seen from the curve (a) in FIG. 2, a strong broad peak appears at 3443cm-1, which is a contraction vibration mode (gamma C-OH) of ethylene glycol hydroxyl, and a large number of hydrogen bonds are formed inside; at 1405cm-1 and 1039cm-1 are respectively the bending vibration peak and the hydroxyl contraction vibration peak of ethylene glycol methylene; as can be seen from the curve (b) in FIG. 2 and the curve (c) in FIG. 2, ethylene glycol, choline chloride and lactic acid are associated by a large number of hydrogen bonds in the process of mixing and eutectic melting at a wave number range of 3500-3000 cm < -1 >; in FIG. 2, (b) the curve shows that methylene of ethylene glycol is associated with choline chloride at 1405cm-1, and contraction vibration of C-C bond of choline chloride and carbonyl contraction vibration peak of lactic acid at 955cm-1 and 1736cm-1, respectively, and the absorption positions of the characteristic structures of ethylene glycol at 1039cm-1 in the curve of FIG. 2 (a) are consistent, indicating that the three components are not destroyed in the eutectic solvent system and exist in association of hydrogen bonds.
Specific examples of the present invention are as follows, and the raw materials used in the following examples are all commercially available products. Examples 1 to 6
The polyol as hydrogen bond donor is mixed with the hydrogen bond acceptor choline chloride ChCl, and the ratio of the two is shown in Table 1, and the ratio is N2Heating and stirring the mixture in an atmosphere and under the condition of oil bath, wherein the heating temperature is 90 ℃, the stirring time is 1h, and after the reaction is finished, a clear binary eutectic solvent DES can be obtained;
adding 5g of perilla leaf residues, 20mL of eutectic solvent and 10mL of distilled water into a three-necked flask in sequence, placing the three-necked flask in an ultrasonic-microwave-ultraviolet light combination instrument, wherein the extraction temperature is 60 ℃, and the reaction time is 20min under the conditions of only microwave power of 450W and no ultrasonic power and ultraviolet light;
after the reaction is finished, the perilla leaf residues and the eutectic solvent rich in anthocyanin are layered. Centrifuging at 9000r/min and 4 deg.C for 10min, filtering with 0.22um porous membrane, and detecting anthocyanin content by pH differential method. The results of obtaining the anthocyanin extraction content are shown in table 1.
TABLE 1
Eutectic solvent
Content/mg 100mg-1
ChCl-glycerol (1:6)
369.9
ChCl-ethylene glycol (1:2)
393.8
ChCl-ethylene glycol (1:3)
397.7
ChCl-ethylene glycol (1:4)
392.4
ChCl-ethylene glycol (1:5)
384.8
ChCl-ethylene glycol (1:6)
379.5
As can be seen from table 1, the highest anthocyanin content was obtained when choline chloride and ethylene glycol were 1:3, without ancillary ligands, only hydrogen bond donor and hydrogen bond acceptor. This is because the solubility of anthocyanins is maximized by the hydrogen bonds formed between choline chloride and ethylene glycol 1:3 and by the covalent bonds between the two molecules.