WO2023151350A1 - Curcumin-loaded composite gel microsphere based on cross-linked corn porous starch, and preparation method therefor - Google Patents

Abstract

A curcumin-loaded composite gel microsphere based on cross-linked corn porous starch. A preparation method for the composite gel microsphere comprises: adding a curcumin/cross-linked porous starch compound into a carboxymethyl cellulose solution, adding zinc oxide, well mixing and stirring in a water bath, dropwise adding the mixture into a ferric chloride or calcium chloride solution to form gel microspheres, then transferring the gel microspheres into a chitosan solution, stirring, and carrying out outer layer film coating treatment. The curcumin/cross-linked porous starch compound is formed by adding cross-linked corn porous starch into a curcumin alcohol solution and carrying out adsorption, the cross-linked corn porous starch is obtained by adding a cross-linking agent into a corn porous starch suspension, and the corn porous starch suspension is obtained from corn porous starch prepared by means of pulsed electric field assisted enzymolysis. The curcumin-loaded composite gel microsphere based on cross-linked corn porous starch can improve the stability of curcumin, and directionally release curcumin to the small intestine or colon.

Description

Composite gel microspheres loaded with cross-linked corn porous starch and curcumin and preparation method thereof technical field

The invention relates to the technical field of curcumin loading, in particular to a composite gel microsphere loaded with curcumin by cross-linked corn porous starch and a preparation method thereof.

Background technique

Curcumin (bis-α, β-unsaturated β-diketone) is a yellow-orange polyphenol derived from the rhizome of turmeric ( Curcuma longa L.), and is a rare pigment with a diketone structure in the plant kingdom. Curcumin is a fat-soluble molecule that has many health benefits such as reducing the risk of cancer, cardiovascular disease, chronic inflammation and metabolic disorders. Due to its unique physiological functions, it is widely used in many fields such as functional food and biomedicine. However, curcumin has the characteristics of poor water solubility, easy degradation, and low oral availability, which limit its application in food and pharmaceuticals. In order to improve the water-solubility and stability of curcumin, protect curcumin from degradation, and increase the bioavailability of curcumin, existing studies often use embedding curcumin in the form of emulsion, solid dispersion and nano-delivery system, among which the preparation New bio-delivery carriers, design and preparation of nano-scale carrier materials, and establishment of slow-release and controlled-release systems are the hotspots of curcumin research in recent years.

Porous starch refers to the modified starch in which microporous structures with a pore size of about 1 μm are distributed on the surface of starch granules. Compared with native starch, porous starch has larger porosity and specific surface area, better water absorption and oil absorption capacity, while retaining the original properties of starch such as non-toxic, harmless, degradable and good biocompatibility . Therefore, porous starch can be used as a wall material to embed active ingredients, protect the active ingredients, and achieve the effect of slow release or specific release of active ingredients. However, there are still some defects in simple porous starch as an adsorbent to adsorb active ingredients, such as the low embedding rate of active ingredients, and the resistance and high sensitivity of porous starch to shear and heat, which limit their use in the field to a certain extent. Application on entrapped active ingredients.

Hydrogel is a gel-like polymer formed by taking water or an aqueous medium as a dispersed phase, having a three-dimensional network structure after swelling, and being able to retain a large amount of solvent, and can be used as a drug carrier. Among them, natural polymer hydrogels are derived from animal and plant tissues in nature, such as chitosan extracted from shrimp shells, alginic acid extracted from kelp, etc. In recent years, a large number of studies have focused on the application of gels formed by chitosan, sodium alginate and carboxymethyl cellulose in the sustained and controlled release of drugs. However, in the process of controlled drug release from a single hydrogel, the difference in the external environment, such as the difference in pH value in the human body, will affect the effect of targeted drug release.

The published curcumin embedding technology and curcumin gel loading technology mainly include: 1) Chinese invention patent 201510429922.9 discloses a method for preparing curcumin microcapsules with egg white powder as the wall material. As the core material, egg white powder and gelatin are used as the wall material, emulsifiers are added, and curcumin microcapsules are obtained by spray drying; however, the spray drying technology involved in this method has higher requirements for equipment and is relatively expensive. 2) Chinese invention patent application 202010546654.X discloses a preparation method of soybean lipophilic protein-curcumin complex, which uses thermal effect to induce the self-assembly of soybean lipophilic protein nanoparticles, and promotes the integration of soybean lipophilic protein nanoparticles and turmeric through ultrasound. The protein interaction improves the loading rate of soybean lipophilic protein; but the heat-induced technology used in this invention to process the structure of soybean lipophilic protein has higher requirements in the actual operation process, and the pH value in the reaction process needs to be strictly controlled, so that The system requirements for the reaction are higher.

technical solution

In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the object of the present invention is to provide a composite gel microsphere using cross-linked corn porous starch to load curcumin and a preparation method thereof, which can release curcumin in a targeted manner.

The invention is mainly based on the cross-linking reaction of starch and the layer-by-layer self-assembly technology of hydrogel. The introduction of pulsed electric field increases the pore size and total pore volume of enzymatically hydrolyzed porous starch, thereby improving the adsorption properties of porous starch. However, the further increase of the pore size may lead to the collapse of the structure of some porous starches. In order to improve the potential problems that may be caused by the pulsed electric field, the enzymatically hydrolyzed porous starch prepared with the assistance of the pulsed electric field was subjected to a cross-linking reaction, and the shear resistance and thermal stability of the porous starch were improved by cross-linking. Then, the cross-linked porous starch is used as an adsorbent to physically adsorb the curcumin to obtain a curcumin/porous starch composite. However, in the process of slow-release of curcumin, the pores of porous starch tend to cause early release of curcumin. To overcome this defect, natural polymer gel materials, such as carboxymethyl cellulose, chitosan, etc., are coated on the surface of curcumin/porous starch, so that curcumin can be released to the small intestine and improve bioavailability. However, the drug-loaded microspheres formed by carboxymethylcellulose or chitosan cannot achieve the effect of curcumin sustained release. The microspheres formed by carboxymethyl cellulose will shrink in the gastric juice, unable to release curcumin, and disintegrate rapidly after entering the intestinal tract, resulting in the explosive release of the drug; chitosan microspheres expand rapidly in the gastric juice, and the drug is released quickly , nor can it play the role of targeted release. Therefore, using the layer-by-layer self-assembly mode, the curcumin/porous starch is embedded layer by layer, first embedded with carboxymethyl cellulose, and then the formed carboxymethyl cellulose microspheres are immersed in the chitosan solution Wrap a layer of chitosan. At the same time, the introduced zinc oxide can improve the mechanical properties and stability of the gel microspheres, and can also regulate the release rate of curcumin in the in vitro simulated release test.

The purpose of the present invention is achieved through the following technical solutions.

The composite gel microspheres of cross-linked corn porous starch loaded with curcumin, the curcumin/cross-linked porous starch composite is added to the carboxymethyl cellulose solution, and zinc oxide is added, and the water bath is mixed and stirred evenly; dripped into the ferric chloride or calcium chloride solution to form gel microspheres, then transfer the gel microspheres to chitosan solution for stirring, and perform outer film wrapping treatment to obtain; curcumin/cross-linked porous starch composite is obtained by cross-linking corn porous starch It is added to curcumin alcohol solution to absorb and form; the cross-linked corn porous starch is obtained by adding a cross-linking agent to the corn porous starch suspension; the corn porous starch suspension is obtained by preparing the corn porous starch assisted by enzymatic hydrolysis with pulse electric field.

In order to further achieve the purpose of the present invention, preferably, the preparation of corn porous starch assisted by pulsed electric field enzymolysis is to prepare corn starch and buffer solution into starch milk, and add a compound enzyme composed of α-amylase and glucoamylase, Water bath enzymatic hydrolysis for 1~2.5 h, stop the reaction, adjust the reactant to neutral, wash with water, wash with alcohol, dry, and crush to obtain porous starch; then mix the porous starch with water to form a uniform starch suspension, and stir evenly , add electrolyte solution, adjust the conductivity of the starch milk solution to 50~400 μS/cm, 20~60 pulsed electric field treatment in the pulsed electric field treatment chamber min, filtered, dried, crushed and sieved to obtain corn porous starch.

Preferably, the electric field intensity of the pulsed electric field is 5~20 kV/cm, and the pulse width is 5~100 μs, pulse frequency 500~2000 Hz; the electric field treatment solution is pumped into the pulse electric field treatment chamber through a peristaltic pump, and the flow rate is controlled at 50-200 mL/min; the electrolyte solution is one or both of potassium chloride solution and potassium sulfate solution, and the concentration of the electrolyte solution is 0.5~2 mol/L.

Preferably, the buffer is acetic acid-sodium acetate buffer or phosphate buffer, the pH of the buffer is 4~5; the mass fraction of native starch in the starch milk is 10~30%; the enzyme activity of α-amylase The enzyme activity of glucoamylase is 5000-200000 U/mL; the mass ratio of α-amylase to glucoamylase is 1:1~1:5; the amount of compound enzyme added is the dry weight of starch 1.5-2.5%; the temperature of enzymatic hydrolysis in water bath is 40~50℃.

Preferably, the cross-linked corn porous starch is prepared by the following method: mixing corn porous starch with deionized water to form a starch suspension, adding a cross-linking agent, adjusting the pH value of the system, and cross-linking reaction 0.5-2 After h, washing, filtering, drying, pulverizing, and sieving to obtain cross-linked porous starch.

Preferably, the cross-linking agent is one of sodium trimetaphosphate (STMP), phosphorus oxychloride (POCl ₃ ), epichlorohydrin (EPCH) and sodium tripolyphosphate (STPP); adjust the pH of the system The value is adjusted by adding a mixture of sodium carbonate and sodium chloride, disodium hydrogen phosphate, and sodium hydroxide; the mass fraction of the porous starch suspension in the starch suspension is 10-30%, and the amount of the crosslinking agent is the mass of the starch suspension. 5-20%; the cross-linking reaction is controlled by the water area, the temperature is 30-50 ℃, the drying is 8-12 h in the blast dryer; the washing is washed 3-5 times with deionized water .

Preferably, the curcumin alcohol solution is formed by dissolving curcumin in ethanol, the concentration of curcumin is 1-3 mg/mL; the adsorption time is 0.5-2 h; cross-linked corn porous starch and turmeric Prime mass ratio 30:1~80:1.

Preferably, according to the amount of raw materials prepared by the composite gel microspheres of cross-linked corn porous starch loaded with curcumin, the mass fraction of the carboxymethyl cellulose solution is 0.5-5%, and the mass fraction of zinc oxide is 0-5%. 2%, the mass fraction of ferric chloride or calcium chloride solution is 1-5%, the mass fraction of chitosan solution is 0.5-3%, and the rest is curcumin/cross-linked porous starch composite.

Preferably, the temperature of the water bath mixing and stirring is 30~50°C, and the stirring speed is 200~600°C. rpm, the stirring time is 0.5 ~ 2 h; the stirring time in the chitosan solution is 0.5 ~ 2 h h, the stirring rate is 200~600 rpm.

The preparation method of the composite gel microsphere of described cross-linked corn porous starch load curcumin, comprises the steps:

1) Preparation of porous starch by enzymatic hydrolysis: prepare corn starch and buffer solution into starch milk, and add a compound enzyme composed of α-amylase and glucoamylase; enzymatic hydrolysis in water bath, adjust the system to neutral after termination, wash with water, and alcohol washing, drying, and pulverization to obtain porous starch;

2) Pulse electric field treatment of porous starch: mix porous starch with water to form a uniform starch suspension, add electrolyte solution to adjust the conductivity of the starch emulsion solution, perform pulse electric field treatment in the pulse electric field treatment chamber, and treat the pulsed electric field. Porous starch, filtered, washed, dried, pulverized, sieved;

3) Preparation of cross-linked corn porous starch: add the cross-linking agent to the pulsed electric field to treat the porous starch suspension, adjust the pH value of the reaction system, stir evenly, react in a water bath, adjust the pH value of the reaction system, terminate the reaction, and wash , filtered, dried, pulverized, sieved;

4) Preparation of curcumin-loaded composite gel microspheres: Dissolve curcumin in ethanol to obtain curcumin alcohol solution, add it to cross-linked corn porous starch, stir to absorb curcumin, filter out unadsorbed curcumin, and obtain Curcumin/cross-linked porous starch complex;

5) Add the curcumin/cross-linked porous starch compound prepared in step 4) to the carboxymethyl cellulose solution, add zinc oxide, mix and stir in a water bath; drop the mixture into ferric chloride or calcium chloride at a constant speed Gel microspheres are formed in the solution, and then the gel microspheres are filtered to remove the ungelled mixture, then the gel microspheres are transferred to the chitosan solution, and then the outer membrane is wrapped to obtain curcumin-loaded Composite gel microspheres.

Preferably, in step 1), the concentration of hydrochloric acid is 1-3 mol/L, and the concentration of sodium hydroxide is 1-3 mol/L.

the

The oil absorption rate of the cross-linked corn porous starch prepared by the invention can reach 90-110%, and has better shear resistance and degradation resistance. However, the oil absorption rate of untreated raw corn starch (that is, the corn raw starch described in step 1) is only 50-60%; after the enzymatic hydrolysis process in step 1), the oil absorption rate of enzymatic hydrolyzed corn porous starch can be The oil absorption rate of the porous starch can reach 80-110% after pulse treatment in step 2) to enzymatically hydrolyze the porous starch. This is because the enzymatic hydrolysis reaction can produce many micropores on the surface of raw corn starch, and also generate a hollow structure, so the specific surface area of porous starch is significantly increased compared with that of native starch. At the same time, the generated micropores can provide better adsorption sites for external substances, thereby improving the adsorption performance of porous starch. In addition, the further treatment of enzymatically hydrolyzed porous starch by pulsed electric field is based on the theory of charge polarization in macroscopic space. The electrolyte that runs through the surface and inside of the porous starch provides additional charges for the porous starch. Under the action of an external electric field of a certain strength, the charges in the electrolyte will undergo charge polarization, thereby generating polarization energy that acts on the porous starch, resulting in The pores of the porous starch are further enlarged, which increases the specific surface area of the porous starch, thereby improving the adsorption performance of the porous starch.

After the cross-linking reaction treatment in step 3), the thermal stability of the cross-linked porous starch is improved, and the thermal decomposition temperature is increased by 2-8 °C compared with that of the uncross-linked porous starch. This is because the cross-linking reaction increases the porous The compactness of the starch structure, the tight structure will limit the movement of molecular chains, increase the resistance to decomposition, and further improve the thermal stability of cross-linked porous starch; at the same time, the swelling force of cross-linked porous starch is compared with that of porous starch Reduced by 0.5~1.5 g/g, this is because the cross-linking of starch molecules and cross-linking agent increases and strengthens the strength of hydrogen bonds, and the increase of hydrogen bond strength will limit the swelling ability of cross-linked porous starch.

The cross-linked porous starch composite adsorbed with curcumin obtained in step 4) has a loading rate of curcumin of more than 60%, indicating that the cross-linked porous starch can be used as an effective adsorbent for curcumin.

The curcumin-loaded composite gel microspheres obtained in step 4) can significantly improve the stability of curcumin, and can retain the activity of curcumin for a long time under light and a certain temperature. At the same time, the outer layer of the gel microspheres is self-assembled layer by layer to form an inside-out carboxymethylcellulose-chitosan coating, which can effectively protect the stability of curcumin and also play a role in delaying drug release. , and at the same time protect curcumin and other drugs from being digested and absorbed in the stomach, and play the role of directional delivery to the small intestine. This is because the outer layer of the composite gel is wrapped with chitosan, which is an alkaline polysaccharide. When it is in an acidic environment such as gastric juice, the amino group of chitosan is protonated, and a large number of cations increase the polarity and electrostatic repulsion to increase the solubility of chitosan, thereby playing the role of dissolving the outer coating of gel microspheres. Carboxymethylcellulose is an anionic cellulose ether substance, and its solubility will increase in an alkaline or weakly alkaline environment, so it can dissolve in the small intestine environment and release active substances such as curcumin for targeted release role.

Beneficial effect

Compared with the prior art, the present invention has the following advantages:

1) The present invention uses pulsed electric field-assisted enzymatic hydrolysis to prepare porous starch, which can prepare porous starch with good adsorption properties in a relatively short period of time, which greatly reduces the reaction time of tens of hours required for chemical or enzymatic preparation. ;

2) The present invention treats the porous starch prepared by enzymatic hydrolysis with pulse electric field, which can increase the pore size, specific surface area and pore volume of the enzymatic porous starch prepared in a short time, and effectively improve the pore-forming rate of porous starch, and then Improve the adsorption rate of porous starch.

3) The present invention uses the cross-linking reaction to carry out cross-linking treatment on the prepared enzymatically hydrolyzed porous starch, which further improves the thermal stability of the porous starch, and the thermal decomposition temperature of the cross-linked porous starch after cross-linking is improved, and also To a certain extent, the adsorption of the cross-linked porous starch is improved, thereby improving the bioavailability of the cross-linked porous starch.

4) The preparation method of the curcumin-loaded composite gel microspheres prepared by the layer-by-layer self-assembly method of the present invention is simple, the raw materials are cheap and easy to obtain, the required equipment is simple, and the selected raw materials are all non-toxic and harmless natural materials. Biodegradable and will not cause harm to the human body.

5) The curcumin-loaded composite gel microspheres provided by the present invention have obvious stabilizing and protective effects on curcumin. After a protection time of 1 week, the curcumin in the embedded curcumin composite gel microspheres The retention rate of is still greater than 50%, while the retention rate of unembedded procurcumin is less than 10%. At the same time, the heat stability and light stability of curcumin after gelation are significantly improved compared with unembedded curcumin. And in the simulated release experiment in vitro, it shows a good effect of directional release in the small intestine and colon.

6) Layer-by-layer self-assembly is a technology that uses the electrostatic interaction of opposite charges to repeatedly deposit on the surface of the colloidal matrix. The gelled layer-by-layer self-assembly of the active ingredient complex plays a role in the targeted release of curcumin, and this method can also be extended to other drug delivery systems.

Description of drawings

Fig. 1 is a diagram of the specific surface area and the average diameter of pores of porous starch without pulse treatment and after pulse treatment in Comparative Example 1 of the present invention.

Fig. 2(a) is a data diagram of TG thermogravimetric analysis of porous starch in Comparative Example 2 of the present invention.

Figure 2(b) is a data diagram of TG thermogravimetric analysis of cross-linked porous starch in Comparative Example 2 of the present invention

Fig. 3 is the data graph of the loading rate of different kinds of starch adsorbing curcumin in Comparative Example 3 of the present invention.

Fig. 4(a) is a full spectrum diagram of the surface photoelectron spectra of porous starch and cross-linked porous starch in Example 1 of the present invention.

Fig. 4(b) is a phosphorus element spectrum of the surface photoelectron spectroscopy of the porous starch and the cross-linked porous starch in Example 1 of the present invention.

Fig. 4(c) is the carbon element spectrum of the surface photoelectron spectrum after the porous starch peak fitting in Example 1 of the present invention.

Fig. 4(d) is the carbon element spectrum of the surface photoelectron spectrum after the peak fitting of the cross-linked porous starch in Example 1 of the present invention.

Fig. 5 is a scanning electron micrograph of gel microspheres loaded with curcumin in Example 1 of the present invention.

Fig. 6 is the Fourier transform infrared spectrogram of each component in the curcumin-loaded gel microsphere of Example 1 of the present invention.

Fig. 7 is a graph of in vitro release data of composite gel microspheres formed with different mass fractions of carboxymethylcellulose (CMC) in Example 1 of the present invention.

Fig. 8 is a graph showing in vitro release data of composite gel microspheres formed with different mass fractions of nano zinc oxide particles (ZnO) in Example 2 of the present invention.

Fig. 9 is a graph showing in vitro release data of composite gel microspheres formed from chitosan (Cs) solutions with different mass fractions in Example 3 of the present invention.

Embodiments of the present invention

The present invention will be further described below with reference to the drawings and examples, but the embodiments of the present invention are not limited thereto.

The present invention first utilizes pulsed electric field assisted enzymatic hydrolysis to prepare corn porous starch, which can effectively reduce the time for preparing corn porous starch. To increase the adsorption and shear resistance of porous starch. Subsequently, the obtained cross-linked corn porous starch was used as a curcumin adsorbent to absorb the curcumin alcohol solution, centrifuged and filtered to remove the unadsorbed curcumin/porous starch complex, vacuum freeze-dried, and set aside. Then add the curcumin/porous starch mixture to the carboxymethylcellulose solution dissolved in hot water, mix well, and add zinc oxide at the same time to improve the antibacterial, mechanical and stability of the hydrogel matrix, mix the mixed solution Uniformly, obtain the mixed solution that is mixed with curcumin/porous starch/zinc oxide/carboxymethyl cellulose. Then inject the mixed solution into the ferric chloride solution with a syringe, and stir evenly to obtain curcumin-loaded gel microspheres. Afterwards, the gel microspheres were filtered, and the unembedded substances were washed out with water, and then the gel was transferred to a chitosan solution for layer-by-layer self-assembly embedding to obtain the final composite gel microspheres loaded with curcumin. ball.

Determination of oil absorption rate of porous starch: The determination method of oil absorption rate of porous starch under different treatment conditions is as follows. Weigh the mass of a 10 mL centrifuge tube with 3 small glass beads in advance, record it as M ₀ , and then add about 1g Porous starch was placed in a 10 mL centrifuge tube, weighed the mass M ₁ of the centrifuge tube, then added 4 mL of corn oil, stirred well, and centrifuged at 8000 rpm/min for 15 min, poured off the supernatant, and centrifuged Invert the tube for 10 min to absorb the remaining floating oil, and weigh M ₂ . Then the oil absorption rate OA of the porous starch to be measured can be calculated by the following formula:

OA= (M ₂ - M ₁ )/ (M ₁ - M ₀ )

In the formula: OA represents the oil absorption rate of the porous starch to be tested.

Determination of specific surface area and pore size of porous starch: The specific surface area, total pore volume and pore size distribution of starch samples were determined by low-temperature nitrogen adsorption method. The specific operation is as follows: a fully automatic gas adsorption analyzer is used for measurement. Before measurement, the starch sample is placed under vacuum conditions at 100 °C for 5 h to remove the air adsorbed on the surface of the starch sample. After the sample is cooled to room temperature, the low-temperature nitrogen adsorption test is carried out with high-purity nitrogen as the medium. The sample to be tested is placed in a fully automatic gas adsorption analyzer, and nitrogen is passed through for testing. The nitrogen adsorption amount of the sample to be tested is related to the specific surface area, total pore volume and pore size of the sample. As the test temperature increases, the nitrogen adsorbed by the starch is desorbed, and finally reaches an equilibrium state, and the adsorption-desorption curve and correlation test indicators. Afterwards, the specific surface area, pore volume pore size and pore size distribution of the test sample were calculated by BET method and BJH method.

Comparative example 1:

Preparation of corn porous starch by enzymatic hydrolysis using existing technology: mix raw corn starch with acetic acid-sodium acetate buffer solution with a pH of 5.0, stir magnetically for 15 minutes to disperse the starch suspension evenly, and obtain 30wt% starch homogenate, then add 2% compound enzyme (mass percentage of compound enzyme and starch dry base) for enzymolysis reaction, the compound enzyme in the enzymolysis reaction is α-amylase and glucoamylase, the mass ratio of α-amylase and glucoamylase is 1:2 . The reaction was carried out in a constant temperature water bath at 50 °C, and the water bath reaction time was 1.5 h to obtain the enzymatically hydrolyzed porous starch milk. The reaction was terminated with 1 mol/L hydrochloric acid for 10 min, and then the reaction solution was adjusted to neutral with sodium hydroxide. properties, the cornstarch milk after enzymolysis was washed with ethanol for 3 times, washed with water for 3 times, filtered with suction, and then dried with a blower dryer, the drying temperature was 45°C, the drying time was 12 h, and pulverized Sieve to obtain the porous starch in Comparative Example 1.

Pulse electric field treatment of enzymatically hydrolyzed corn porous starch: mix the porous starch with deionized water to form a uniform starch suspension, stir evenly with a magnetic force, and then add 1 mol/L potassium chloride electrolyte solution to adjust the conductivity of the starch milk solution to 150 μS/cm, using a peristaltic pump to pump into the pulse electric field treatment chamber, the actual treatment time of the pulse electric field is 30 min, the pulse electric field strength was 12 kV/cm, the pulse width was 40 μs, the pulse frequency was 1000 Hz, and the flow rate was 100 mL/min. The porous starch treated by the pulse electric field was filtered, washed three times with deionized water, dried in a blast drying oven for 12 h, crushed, and sieved to obtain the corn porous starch prepared by pulse electric field-assisted enzymatic hydrolysis in Comparative Example 1.

Then, the prepared enzymolyzed porous starch and the enzymolyzed porous starch after pulse treatment were tested for oil absorption, specific surface area and pore size. Obtained through the test of oil absorption rate, the oil absorption rate of enzymatic hydrolyzed porous corn starch in comparative example 1 reaches 76.16%, and the oil absorption rate of enzymolyzed porous corn starch after pulse reaches 88.35%; As shown in Figure 1, the enzymatic hydrolyzed porous corn starch The specific surface area is 4.174 cc/g, the average pore diameter is 8.271 nm, the specific surface area of the enzymatic hydrolyzed corn porous starch after pulse treatment is 5.056 cc/g, and the average pore diameter is 18.11 nm.

Comparative example 2:

The enzymolyzed corn porous starch obtained in Comparative Example 1 is cross-linked, and the porous starch is mixed with deionized water to form a starch suspension of 15% mass fraction, stirred evenly, and then 10wt% sodium trimetaphosphate is added as a cross-linking agent. Linking agent (mass percentage of sodium trimetaphosphate and starch dry basis), stirring reaction was carried out on a magnetic stirrer, and the speed of magnetic stirring was 400 rpm, water bath temperature is 40 ℃, add 0.2 mL of sodium carbonate and 0.5 g of sodium chloride were dissolved in 20 mL of deionized water to adjust the pH value of the reaction system. The reaction time in the water bath was 1 h, and the reaction was terminated for 15 min. Dry for 12 h, pulverize, and sieve to obtain the cross-linked corn porous starch in Comparative Example 2.

The thermal properties of cross-linked porous starch and uncross-linked porous starch were tested by thermogravimetric analysis. The results are shown in Figure 2. The maximum thermal decomposition temperature of cross-linked porous starch in Figure 2(b) is 313.9 °C, which is higher than the maximum thermal decomposition temperature of uncrosslinked porous starch in Fig. 2(a) of 310.9 °C. These results indicate that crosslinked porous starch has better thermal stability than uncrosslinked porous starch.

Comparative example 3:

In order to further verify the effects of separate enzymatic hydrolysis treatment and single pulse treatment, as well as co-treatment of enzymatic hydrolysis and pulse treatment, and cross-linking treatment of porous starch on the adsorption properties of starch samples. In this comparative example, corn raw starch, corn raw starch after pulse treatment, enzymatically hydrolyzed corn porous starch, pulse treated porous starch and cross-linked porous starch were used as carriers for adsorbing curcumin. Prepare 1 with absolute ethanol mg/mL curcumin solution, stir until curcumin is completely dissolved in ethanol. Next, add 5 g of corn porous starch into 50 mL of water, stir well to make it into a starch suspension, then add 50 mL of curcumin alcohol solution, (curcumin: porous starch 1:100) and package at 40 °C 1h. Then take 3 mL of curcumin/cross-linked porous starch composite solution and centrifuge at 5000 rpm for 10 min to remove unembedded curcumin, collect the supernatant after centrifugation, and then use a UV spectrophotometer at 425 The absorbance value was measured at nm, and the content of curcumin in the supernatant was calculated according to the relationship between the curcumin content and the absorbance value at 425 nm. The precipitate was dried at 50 °C for 5 h, then crushed, sieved with an 80-mesh sieve and stored in a desiccator. The adsorption rate was calculated by the following formula:

Adsorption rate (%)=(m ₂ -m ₁ )/m ₂ ×100

Wherein, m ₁ is the mass of curcumin in the supernatant after centrifugation of the curcumin embedding solution, and m ₂ is the mass of total curcumin added to the embedding, in mg.

The results are shown in Figure 3. Through the measurement of the adsorption rate of curcumin, the curcumin adsorption rate of corn raw starch was 56.78%, the curcumin adsorption rate of enzymatic hydrolyzed corn porous starch was 59.44%, and the enzymatic hydrolyzed corn porous starch after pulse treatment The curcumin adsorption rate of starch was 60.82%, and the curcumin adsorption rate of cross-linked corn porous starch was 61.11%. These results indicated that the synergy between pulsed electric field and cross-linking reaction would increase the curcumin adsorption rate of porous starch.

Example 1:

Preparation of porous corn starch by enzymatic hydrolysis: mix raw corn starch with acetic acid-sodium acetate buffer solution with a pH of 5.0, and stir magnetically for 15 minutes to disperse the starch suspension evenly to obtain a 30wt% starch homogenate, then add 2% The compound enzyme (mass percentage of the compound enzyme and starch dry base) performs an enzymolysis reaction. In the enzymolysis reaction, the compound enzyme is α-amylase and glucoamylase, and the mass ratio of α-amylase and glucoamylase is 1:2. The reaction was carried out in a constant temperature water bath at 50 °C, and the water bath reaction time was 1.5 h to obtain the enzymatically hydrolyzed porous starch milk. The reaction was terminated with 1 mol/L hydrochloric acid for 10 min, and then the reaction solution was adjusted to neutral with sodium hydroxide. properties, the cornstarch milk after enzymolysis was washed with ethanol for 3 times, washed with water for 3 times, filtered with suction, and then dried with a blower dryer, the drying temperature was 45°C, the drying time was 12 h, and pulverized Sieve to obtain porous starch.

Pulse electric field treatment of enzymatically hydrolyzed corn porous starch: mix the porous starch with deionized water to form a uniform starch suspension, stir evenly with a magnetic force, and then add 1 mol/L potassium chloride electrolyte solution to adjust the conductivity of the starch milk solution to 150 μS/cm, using a peristaltic pump to pump into the pulse electric field treatment chamber, the actual treatment time of the pulse electric field is 30 min, the pulse electric field strength was 12 kV/cm, the pulse width was 40 μs, the pulse frequency was 1000 Hz, and the flow rate was 100 mL/min. The porous starch treated by the pulse electric field was filtered, washed three times with deionized water, dried in a blast drying oven for 12 h, crushed, and sieved to obtain the finished product.

Preparation of cross-linked corn porous starch: cross-link the corn porous starch prepared by pulse electric field-assisted enzymolysis obtained above, mix the porous starch and deionized water to form a starch suspension with a mass fraction of 15%, stir evenly, and then Add 10wt% sodium trimetaphosphate as cross-linking agent (sodium trimetaphosphate and starch dry basis mass percentage), carry out stirring reaction on magnetic stirrer, the speed of magnetic stirring is 400 rpm, water bath temperature is 40 ℃, add 0.2 mL of sodium carbonate and 0.5 g of sodium chloride were dissolved in 20 mL of deionized water to adjust the pH value of the reaction system. The reaction time in the water bath was 1 h, and the reaction was terminated for 15 min. Dry for 12 h, crush and sieve to obtain cross-linked porous starch. In order to verify whether the cross-linked porous starch was successfully synthesized, it was tested by surface photoelectron spectroscopy. The results are shown in Figure 4, the full spectrum of the surface photoelectron spectrum of cross-linked porous starch and porous starch, the photoelectron energy of carbon, oxygen, and phosphorus The spectrogram results show that compared with porous starch, cross-linked porous starch produces a new C-O-P absorption peak in the carbon photoelectron spectrum and oxygen photoelectron spectrum, which indicates that trimetaphosphoric acid is introduced into the cross-linked porous starch Phosphorus element in sodium, which proves that the cross-linking reaction is successfully carried out.

Preparation of Curcumin/Crosslinked Porous Corn Starch Complex: Formulated with Absolute Ethanol 1 mg/mL curcumin solution 50 mL, stir well until curcumin is completely dissolved. Subsequently, 5 g of corn porous starch was added to 50 mL of water, stirred evenly to make it into a starch suspension, then the curcuminol solution and the starch suspension were mixed, and embedded at a speed of 300 rpm at 40 °C. The embedding process was protected from light, and embedded for 1 h. Then take 3 mL of curcumin/cross-linked porous starch complex solution and centrifuge at 5000 rpm for 10 min, to remove unembedded curcumin, collect the supernatant after centrifugation, then measure the absorbance at 425 nm with a UV spectrophotometer, and calculate the supernatant according to the relationship between the content of curcumin and the absorbance at 425 nm content of curcumin in. Subsequently, the curcumin/cross-linked porous starch complex is suction-filtered, washed 3 times with water, washed 3 times with alcohol, vacuum freeze-dried and filtered, then pulverized, sieved with 80 mesh sieves and stored in a desiccator in the dark. Obtain curcumin/cross-linked porous complex.

Preparation of curcumin-loaded composite gel microspheres: take carboxymethyl cellulose with final mass percentages of 1%, 2%, 3% and 4% after being dissolved in water respectively, dissolve them in warm water at 50°C, and then Dissolve zinc oxide with a final concentration of 0.5% and curcumin/cross-linked porous starch composite with 0.5 g in deionized water, dilute to 100 mL, and stir evenly. Pour the mixture of zinc oxide and curcumin/cross-linked porous starch into the carboxymethyl cellulose solution, mix and stir evenly, and then use a syringe with a 10 mm inner diameter to inject the above mixture into the 3% _FeCl3 solution by mass fraction . Gel microspheres were cross-linked in _FeCl solution for 30 min, filtered, washed with water, and the prepared microspheres wrapped with carboxymethyl fibers were transferred to 100 mL of chitosan solution with a mass fraction of 1%, 100 rpm , and react at room temperature for 30 min to obtain composite gel microspheres loaded with curcumin.

The resulting curcumin-loaded gel microspheres were characterized for their morphology and structure, and the morphology of the curcumin-loaded gel microspheres after drying was analyzed by scanning electron microscopy. The results are shown in Figure 5. The gel microspheres formed The surface of the glue microspheres was wrinkled, and there was no obvious cavity structure inside. The curcumin was mixed evenly with viscous carboxymethyl cellulose during the embedding process, and the scanning electron microscope image could not visually observe the curcumin. Distribution.

Test the Fourier transform infrared spectra of the gel microspheres and each component, and the results are shown in Figure 6. First, at the peaks of 3445 cm ^-1 and 3430 cm ^-1 in CMC and Cs, the hydroxyl peaks become wider and, in ZnO@CMC@Cs microspheres, shifted to a lower frequency of 3430 cm ^-1 , indicating the formation of hydrogen bonds between the carboxyl groups of CMC and the hydroxyl groups of Cs and the stretching vibrations of -NH ₂ and -OH groups superposition. Secondly, the intensity of the carboxyl peak at 1580 cm ^-1 decreases, and in the range of 1000 cm ^-1 to 1200 cm ^-1 , the iron-oxygen bond is partially covalently bonded. These phenomena are due to the formation of Fe ³⁺ and the deprotonated carboxylate group of CMC Ionic bonds are formed. Some small peaks increase in intensity at 1400 cm ^-1 ~1600 cm ^-1 , and a new absorption band is observed at 1590 cm ^-1 , which can be explained as the interaction between the amino group in Cs and the carboxyl group in CMC to form a polyelectrolyte structure, some new hydrogen bonds were formed between chitosan and ZnO nanoparticles.

The prepared composite gel microspheres were subjected to in vitro digestion and release tests in simulated gastric fluid (SGF, pH=1.2), simulated small intestinal fluid (SIF, pH=6.8) and simulated colonic fluid (SCF, pH = 7.4) for 2 hours, 3 hours, and 3 hours of in vitro digestion and release tests. Finally, the in vitro release of curcumin was judged by measuring the concentration of curcumin in the digestive juice.

It was measured that the adsorption rate of curcumin on cross-linked porous starch was 61.11%, the loading rate of curcumin loaded on the prepared gel microspheres was 56.88%, and the loading capacity was 5.69 mg/g. The thermal stability of cross-linked porous starch is more stable than that of porous starch, and the specific performance is that the maximum thermal decomposition temperature of cross-linked porous starch is 313.9 ℃, higher than the maximum thermal decomposition temperature of porous starch 310.4 ℃. In vitro digestion experiments showed that the release rate of curcumin in simulated gastric juice (pH = 1.2) was relatively low, as shown in Figure 7. Within 2 h, the mass fraction of 1% to 4% carboxymethyl cellulose formed The release rates of the microspheres were 12.02%, 9.36%, 6.56% and 6.36%, respectively. Afterwards, the cumulative release amount in simulated small intestinal fluid (pH=6.8) and simulated colonic fluid (pH=7.4) reached 69.15%, 75.86%, 80.35% and 73.65%, respectively.

Example 2:

Preparation of enzymatically hydrolyzed corn porous starch: configure 30% starch homogenate according to the method in Example 1, add 2% compound enzyme (weight ratio of compound enzyme to starch dry basis) for enzymolysis reaction, α-amylase: saccharification The mass ratio of the enzyme was 1:2, the stirring rate of the water bath was 500 rpm, and the temperature of the water bath was 50 °C. After 1.5 h of reaction time, the pH of the system was adjusted to 1.2-1.5 with 1 mol/L hydrochloric acid, and the reaction was terminated for 10 min. Sodium hydroxide is used to adjust the pH of the system to neutral, and the reaction mixture is suction filtered, washed, dried, pulverized, and sieved until porous starch is obtained.

Pulse electric field treatment of enzymatically hydrolyzed corn porous starch: mix the porous starch with deionized water to form a uniform starch suspension, stir evenly with a magnetic force, and then add 1 mol/L potassium chloride electrolyte solution to adjust the conductivity of the starch milk solution to 150 μS/cm, using a peristaltic pump to pump into the pulse electric field treatment chamber, the actual treatment time of the pulse electric field is 30 min, the pulse electric field strength was 12 kV/cm, the pulse width was 40 μs, the pulse frequency was 1000 Hz, and the flow rate was 100 mL/min. The porous starch treated by the pulse electric field was filtered, washed three times with deionized water, dried in a blast drying oven for 12 h, crushed, and sieved to obtain the finished product.

Preparation of cross-linked porous starch: The corn porous starch prepared above by pulsed electric field-assisted enzymolysis was cross-linked, and the porous starch and deionized water were prepared into a starch suspension with a mass fraction of 15%, and then added with a mass ratio of 10 % sodium trimetaphosphate as a cross-linking agent (sodium trimetaphosphate: starch dry basis mass ratio), stirring on a magnetic stirrer, the rate is 400 rpm, water bath temperature is 40℃, add 0.2 mL of sodium carbonate and 0.5 g of sodium chloride were dissolved in 20 mL of deionized water to adjust the pH value of the reaction system. The reaction time in the water bath was 1 h, and the reaction was terminated for 15 min. Dry for 12 h, crush and sieve to obtain the cross-linked corn porous starch.

Preparation of curcumin-loaded composite gel microspheres: take carboxymethyl cellulose with final mass percentages of 1%, 2%, 3% and 4% after being dissolved in water respectively, dissolve them in warm water at 50°C, and then Dissolve zinc oxide with a final concentration of 0.5% and curcumin/cross-linked porous starch composite with 0.5 g in deionized water, dilute to 100 mL, and stir evenly. Pour the mixture of zinc oxide and curcumin/cross-linked porous starch into the carboxymethyl cellulose solution, mix and stir evenly, and then use a syringe with a 10 mm inner diameter to inject the above mixture into the 3% _FeCl3 solution by mass fraction . Gel microspheres were cross-linked in _FeCl solution for 30 min, filtered, washed with water, and the prepared microspheres wrapped with carboxymethyl fibers were transferred to 100 mL of chitosan solution with a mass fraction of 1%, 100 rpm , and react at room temperature for 30 min to obtain composite gel microspheres loaded with curcumin.

Preparation of curcumin-loaded composite gel microspheres: take 0%, 0.25%, 0.50% and 1.00% zinc oxide nanoparticles by mass fraction, dissolve them in a certain volume of warm water at 50°C, and then take 3% Carboxymethyl cellulose and 0.5 g of curcumin/cross-linked porous starch complex were dissolved in a certain volume of deionized water, and the volume was adjusted to 100 ml, and stirred evenly. Pour the mixture of zinc oxide and curcumin/cross-linked porous starch into the carboxymethyl cellulose solution, mix and stir evenly, and then use a syringe with a 10 mm inner diameter to inject the above mixture into the 3% _FeCl3 solution by mass fraction . The gel microspheres were cross-linked in _FeCl solution for 30 min, filtered, washed with water, and the prepared microspheres wrapped with carboxymethyl fibers were transferred to a chitosan solution with a mass fraction of 1%, 100 rpm, and reacted at room temperature After 30 min, composite gel microspheres loaded with curcumin were obtained. Afterwards, the prepared composite gel microspheres were subjected to in vitro digestion and release tests in simulated gastric fluid (SGF, pH=1.2), simulated small intestine fluid (SIF, pH=6.8) and simulated colonic fluid (SCF, pH=7.4 ) in vitro digestion and release tests for 2 hours, 3 hours, and 3 hours respectively. Finally, the adsorption rate of curcumin adsorbed by cross-linked porous starch, the loading rate of curcumin loaded on composite gel microspheres, and the release of composite gel microspheres in vitro were measured.

It was measured that the adsorption rate of curcumin on cross-linked porous starch was 61.11%, the loading rate of curcumin loaded on the prepared gel microspheres was 56.88%, and the loading capacity was 5.69 mg/g. The thermal stability of cross-linked porous starch is more stable than that of porous starch, specifically shown that the maximum thermal decomposition temperature of cross-linked porous starch is 313.9 ℃, higher than the maximum thermal decomposition temperature of porous starch 310.4 ℃. In vitro digestion experiments showed that the release rate of curcumin in simulated gastric juice (pH = 1.2) was relatively low, as shown in Figure 8. Within 2 h, the microparticles formed by zinc oxide nanoparticles with a mass fraction of 0% to 1.00% The ball release rates were 7.52%, 5.76%, 5.39% and 5.06%, respectively. Afterwards, the cumulative release amount in simulated small intestinal fluid (pH=6.8) and simulated colonic fluid (pH=7.4) reached 79.35%, 74.83%, 73.67% and 68.15%, respectively.

Example 3:

Preparation of enzymatically hydrolyzed corn porous starch: configure 30% starch homogenate according to the method in Example 1, add 2% compound enzyme (weight ratio of compound enzyme to starch dry basis) for enzymolysis reaction, α-amylase: saccharification The mass ratio of the enzyme was 1:2, the stirring rate of the water bath was 500 rpm, and the temperature of the water bath was 50 °C. After 1.5 h of reaction time, the pH of the system was adjusted to 1.2-1.5 with 1 mol/L hydrochloric acid, and the reaction was terminated for 10 min. Sodium hydroxide is used to adjust the pH of the system to neutral, and the reaction mixture is suction filtered, washed, dried, pulverized, and sieved until porous starch is obtained.

Pulse electric field treatment of enzymatically hydrolyzed corn porous starch: mix the porous starch with deionized water to form a uniform starch suspension, stir evenly with a magnetic force, and then add 1 mol/L potassium chloride electrolyte solution to adjust the conductivity of the starch milk solution to 150 μS/cm, using a peristaltic pump to pump into the pulse electric field treatment chamber, the actual treatment time of the pulse electric field is 30 min, the pulse electric field strength was 12 kV/cm, the pulse width was 40 μs, the pulse frequency was 1000 Hz, and the flow rate was 100 mL/min. The porous starch treated by the pulse electric field was filtered, washed three times with deionized water, dried in a blast drying oven for 12 h, crushed, and sieved to obtain the finished product.

Preparation of cross-linked porous starch: The corn porous starch prepared above by pulsed electric field assisted enzymatic hydrolysis was cross-linked, and the porous starch and deionized water were prepared into a starch suspension with a mass fraction of 15, and then added with a mass ratio of 10% Sodium trimetaphosphate was used as a cross-linking agent (sodium trimetaphosphate:starch dry basis mass ratio), stirred on a magnetic stirrer at a speed of 400rpm, and a water bath temperature of 40°C, adding 0.2 mL of sodium carbonate and 0.5 g of chloride Sodium was added to 20 mL deionized water to adjust the pH value of the reaction system. The reaction time in the water bath was 1 h, and the reaction was terminated for 15 min. The reaction mixture was washed 3 times with deionized water, dried in a blast dryer for 12 h, pulverized, and sieved. , to obtain cross-linked corn porous starch.

Preparation of composite gel microspheres loaded with curcumin: 3% carboxymethyl cellulose, 0.5% zinc oxide and 0.5 g curcumin/cross-linked porous starch composite were dissolved in certain Volume of deionized water, dilute to 100 mL, stir well. Mix evenly, and then use a syringe with an inner diameter of 10 mm to inject the above mixture into a 3% mass fraction of FeCl ₃ solution. The gel microspheres were cross-linked in _FeCl solution for 30 min, filtered, washed with water, and the prepared microspheres wrapped with carboxymethyl fibers were transferred to 0.25%, 0.5%, 1% and 1.25% mass fraction of chitosan In the sugar solution, 100 rpm, 30 min at room temperature, the composite gel microspheres loaded with curcumin were obtained. Afterwards, the prepared composite gel microspheres were subjected to in vitro digestion and release tests in simulated gastric fluid (SGF, pH=1.2), simulated small intestine fluid (SIF, pH=6.8) and simulated colonic fluid (SCF, pH=7.4 ) in vitro digestion and release tests for 2 hours, 3 hours, and 3 hours respectively. Finally, the adsorption rate of curcumin adsorbed by cross-linked porous starch, the loading rate of curcumin loaded on composite gel microspheres, and the release of composite gel microspheres in vitro were measured.

It was measured that the adsorption rate of curcumin on cross-linked porous starch was 61.11%, the loading rate of the prepared gel microspheres was 56.88%, and the loading capacity was 5.69 mg/g. The thermal stability of cross-linked porous starch is more stable than that of porous starch, specifically shown that the maximum thermal decomposition temperature of cross-linked porous starch is 313.9 ℃, higher than the maximum thermal decomposition temperature of porous starch 310.4 ℃. In vitro digestion experiments showed that the release rate of curcumin in simulated gastric juice (pH = 1.2) was relatively low, as shown in Fig. The ball release rates were 5.26%, 6.16%, 7.33% and 8.62%, respectively. Afterwards, the cumulative release amount in simulated small intestinal fluid (pH=6.8) and simulated colonic fluid (pH=7.4) reached 79.06%, 79.56%, 75.75% and 72.17%, respectively.

The invention utilizes pulsed electric field to assist in the preparation of enzymatically hydrolyzed corn porous starch, which can efficiently prepare corn porous starch with high adsorption and drug loading; meanwhile, the layer-by-layer self-assembly technology of hydrogel can effectively improve the stability and target of curcumin. toward release. Therefore, the present invention is aimed at the preparation of porous starch and the preparation of hydrogel to construct an effective drug delivery system, which is of great significance to the growing market demand of people. The invention performs pulse electric field treatment on the corn porous starch obtained by enzymolysis. Compared with the porous starch obtained by direct enzymolysis, the pulse electric field can effectively reduce the time of enzymolysis, and simultaneously obtain higher adsorption and drug loading rate. Carboxymethyl cellulose and chitosan composite gelation treatment of porous starch/curcumin complex with curcumin can effectively improve the stability of curcumin and achieve the effect of directional release. It is a kind of Very effective drug delivery system.

The embodiments of the present invention are not limited by the examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods, including Within the protection scope of the present invention.

Claims (10)

1. The composite gel microsphere of cross-linked corn porous starch loaded with curcumin is characterized in that, the curcumin/cross-linked porous starch compound is added to the carboxymethyl cellulose solution, and zinc oxide is added, and the water bath is mixed and stirred evenly; into ferric chloride or calcium chloride solution to form gel microspheres, then transfer the gel microspheres to chitosan solution for stirring, and perform outer membrane wrapping treatment to obtain; curcumin/cross-linked porous starch composite is obtained by cross-linking Linked corn porous starch is added to curcumin alcohol solution for adsorption; cross-linked corn porous starch is obtained by adding a cross-linking agent to corn porous starch suspension; corn porous starch suspension is prepared by pulse electric field assisted enzymatic hydrolysis of corn porous Starch gets.
2. The composite gel microsphere of cross-linked corn porous starch loaded with curcumin according to claim 1, wherein said pulse electric field assisted enzymatic hydrolysis to prepare corn porous starch is to configure corn raw starch and buffer solution into starch milk, And add a compound enzyme composed of α-amylase and glucoamylase, hydrolyze in a water bath for 1-2.5 h, stop the reaction, adjust the reactant to neutral, wash with water, wash with alcohol, dry, and crush to obtain porous starch; then porous starch Mix starch and water to form a uniform starch suspension, stir evenly, add electrolyte solution, adjust the conductivity of the starch milk solution to 50-400 μS/cm, treat with pulse electric field for 20-60 min in the pulse electric field treatment chamber, filter, and dry , pulverized and sieved to obtain corn porous starch.
3. The composite gel microsphere of crosslinked corn porous starch loaded curcumin according to claim 2, it is characterized in that, the electric field strength of described pulse electric field is 5～20 kV/cm, and pulse width is 5～100 μ s, The pulse frequency is 500-2000 Hz; the electric field treatment solution is pumped into the pulse electric field treatment chamber through a peristaltic pump, and the flow rate is controlled at 50-200 mL/min; the electrolyte solution is one or both of potassium chloride solution and potassium sulfate solution. species, the concentration of the electrolyte solution is 0.5-2 mol/L.
4. The composite gel microsphere of crosslinked corn porous starch loaded curcumin according to claim 2, it is characterized in that, described buffer is acetic acid-sodium acetate buffer or phosphate buffer, and buffer pH value is 4 ~ 5. The mass fraction of raw starch in starch milk is 10-30%; the enzyme activity of α-amylase is 3000-5000 U/mL, and the enzyme activity of glucoamylase is 5000-200000 U/mL; α-amylase and glucoamylase The mass ratio of the starch is 1:1~1:5; the amount of compound enzyme added is 1.5-2.5% of the dry basis of starch; the temperature of enzymolysis in water bath is 40~50°C.
5. The composite gel microspheres of cross-linked corn porous starch loaded with curcumin according to claim 1, wherein the cross-linked corn porous starch is prepared by the following method: the corn porous starch is mixed with deionized water to form Add a cross-linking agent to the starch suspension to adjust the pH value of the system. After the cross-linking reaction takes 0.5-2 hours, wash, filter, dry, pulverize, and sieve to obtain the cross-linked porous starch.
6. The composite gel microsphere of crosslinked corn porous starch load curcumin according to claim 5, is characterized in that, described crosslinking agent is sodium trimetaphosphate, phosphorus oxychloride, epichlorohydrin and sodium tripolyphosphate A kind of; the pH value of the adjustment system is adjusted by adding a mixture of sodium carbonate and sodium chloride, disodium hydrogen phosphate, and sodium hydroxide; the mass fraction of the porous starch suspension in the starch suspension is 10-30%, and the crosslinking agent The dosage is 5-20% of the mass of the starch suspension; the cross-linking reaction is controlled by the water area, the temperature is 30-50°C, and the drying is 8-12h in a blast dryer; the washing is done with deionized water Wash 3-5 times.
7. The composite gel microsphere of cross-linked corn porous starch loaded curcumin according to claim 1, wherein said curcumin alcohol solution is formed by dissolving curcumin in ethanol, and the concentration of curcumin is 1 ~ 3mg /mL; the adsorption time is 0.5-2 h; the mass ratio of cross-linked corn porous starch to curcumin is 30:1-80:1.
8. The composite gel microsphere of cross-linked corn porous starch loaded curcumin according to claim 1, is characterized in that, according to the raw material consumption meter prepared by the composite gel microsphere of cross-linked corn porous starch loaded curcumin, the carboxyl The mass fraction of methylcellulose solution is 0.5-5%, the mass fraction of zinc oxide is 0-2%, the mass fraction of ferric chloride or calcium chloride solution is 1-5%, and the mass fraction of chitosan solution is 0.5~3%, the rest is curcumin/cross-linked porous starch compound.
9. The composite gel microsphere of crosslinked corn porous starch loaded curcumin according to claim 1, it is characterized in that, the temperature of described water bath mixing and stirring is 30～50 ℃, and the speed of stirring is 200～600 rpm, and the stirring time is 0.5-2 h; the stirring time in the chitosan solution is 0.5-2 h, and the stirring rate is 200-600 rpm.
10. The preparation method of the composite gel microsphere of crosslinked corn porous starch loaded curcumin described in any one of claim 1-9, is characterized in that comprising the steps:

    1) Preparation of porous starch by enzymatic hydrolysis: prepare corn starch and buffer solution into starch milk, and add a compound enzyme composed of α-amylase and glucoamylase; enzymatic hydrolysis in water bath, adjust the system to neutral after termination, wash with water, and alcohol washing, drying, and pulverization to obtain porous starch;

    2) Pulse electric field treatment of porous starch: mix porous starch with water to form a uniform starch suspension, add electrolyte solution to adjust the conductivity of the starch emulsion solution, perform pulse electric field treatment in the pulse electric field treatment chamber, and treat the pulsed electric field. Porous starch, filtered, washed, dried, pulverized, sieved;

    3) Preparation of cross-linked corn porous starch: add the cross-linking agent to the pulsed electric field to treat the porous starch suspension, adjust the pH value of the reaction system, stir evenly, react in a water bath, adjust the pH value of the reaction system, terminate the reaction, and wash , filtered, dried, pulverized, sieved;

    4) Preparation of curcumin-loaded composite gel microspheres: Dissolve curcumin in ethanol to obtain curcumin alcohol solution, add it to cross-linked corn porous starch, stir to absorb curcumin, filter out unadsorbed curcumin, and obtain Curcumin/cross-linked porous starch complex;

    5) Add the curcumin/cross-linked porous starch compound prepared in step 4) to the carboxymethyl cellulose solution, add zinc oxide, mix and stir in a water bath; drop the mixture into ferric chloride or calcium chloride at a constant speed Gel microspheres are formed in the solution, and then the gel microspheres are filtered to remove the ungelled mixture, then the gel microspheres are transferred to the chitosan solution, and then the outer membrane is wrapped to obtain curcumin-loaded Composite gel microspheres.