A method for preparing caffeine-free chlorogenic acid

Abstract

The present invention belongs to the technical field of chlorogenic acid extraction, and specifically relates to a method for preparing caffeine-free chlorogenic acid, comprising: crushing green coffee beans into particles, and subjecting them to salt-alcohol composite extraction of sodium chloride-ethanol, and then subjecting them to acetone extraction using acetone, and subjecting them to resin elution and solvent dissolution to obtain caffeine-free chlorogenic acid, and achieving the effect of co-production of caffeine. The present invention solves the problem of caffeine contained in chlorogenic acid, and realizes the gradient removal of caffeine by combining resin adsorption and solvent, and realizes the leaching removal effect of caffeine by combining the solubility difference of chlorogenic acid and caffeine.

Description

Technical Field

[0001] The invention belongs to the technical field of chlorogenic acid extraction, and particularly relates to a method for preparing caffeine-free chlorogenic acid. Background Art

[0002] Chlorogenic acid is an ester formed by caffeic acid and quinic acid. It is an important bioactive substance with a wide range of pharmacological effects and biological activities. It is not only the main effective ingredient of many medicinal materials and Chinese patent medicines for antibacterial, detoxification, anti-inflammatory and choleretic effects, but also has three unstable parts in its molecular structure: ester bond, unsaturated double bond and polyphenol. It also has antiviral, white blood cell increase, anti-tumor, blood pressure reduction, blood lipid reduction, free radical scavenging and central nervous system excitation. Chlorogenic acid is widely present in plants, with the highest content in honeysuckle, eucommia and green coffee beans. The efficient extraction of chlorogenic acid from natural plants is a research hotspot at home and abroad. Green coffee beans come from the seeds of small-fruit coffee, medium-fruit coffee and large-fruit coffee of the Rubiaceae family. Green coffee beans contain more chlorogenic acid and can be used as the raw material for chlorogenic acid extract. However, green coffee contains caffeine. When extracting chlorogenic acid, caffeine is mixed in the chlorogenic acid extract as an impurity and is difficult to remove, resulting in poor purity of chlorogenic acid. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides a method for preparing caffeine-free chlorogenic acid, which solves the problem of caffeine contained in chlorogenic acid. The gradient removal of caffeine is achieved by combining resin adsorption and solvent, and the solubility difference between chlorogenic acid and caffeine is combined to achieve the caffeine removal effect.

[0004] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0005] A method for preparing caffeine-free chlorogenic acid comprises the following steps:

[0006] Step 1, refining green coffee beans into particles, then adding them into sodium chloride-ethanol colloid and stirring evenly, and forming a homogeneous colloid after wet ball milling; the green coffee beans are formed into fine powder particles by mechanical crushing, the mass ratio of sodium chloride to ethanol in the sodium chloride-ethanol colloid is 1:1-2, the mass ratio of green coffee beans to sodium chloride is 10:1-3, and the stirring speed is 1000-2000r / min; the temperature of wet ball milling treatment is 30-50°C, and the ball milling pressure is 0.5-0.9MPa; in this treatment process, the green coffee beans are mechanically crushed to form fine powder particles, which are physical forms of mechanical destruction and will not affect the active ingredients. At the same time, in the crushing process, the coffee beans are broken by force, which greatly increases the exposed area, thereby causing a sharp increase in the subsequent contact area; when the fine powder particles are placed in the sodium chloride ethanol colloid, sodium chloride itself is insoluble in ethanol, Ethanol forms fine particles with a colloidal structure, that is, sodium chloride forms a stable dispersed structure in the system, and at the same time, sodium chloride is uniformly distributed in the ethanol in the form of fine particles. When the green coffee fine powder particles are placed in the colloid solution, the fine particles of sodium chloride can be used as ball milling particles to further crush the fine powder particles based on the stability of their own structure during the ball milling process, further reducing the particle size of the fine particles and increasing the specific surface area of ​​the green coffee particles. At the same time, the water absorption of sodium chloride itself can absorb and release water molecules on the surface of the green coffee particles during the contact process, causing the surface of the green coffee particles to be inactivated, that is, the activity of the green coffee particles is reduced, the grindability of the green coffee particles is improved, and the refining effect of the green coffee particles is greatly improved. Based on the permeability and dissolution effect of ethanol, the green coffee fine powder particles are formed into a preliminary dissolution system; therefore, in this step, the preliminary dissolution is a composite extraction system formed by salt extraction and alcohol extraction;

[0007] Step 2, the homogenized colloid is allowed to stand and dry, then acetone is added for low-temperature ultrasonic treatment for 20-30 minutes, sealed for 2-3 hours, and naturally cooled to obtain a slurry, the standing temperature is 30-40°C, the concentration of the ultrasonic treatment is 30-50g / L, the temperature of the low-temperature ultrasonic treatment is 5-10°C, the ultrasonic frequency is 50-70kHz, the temperature of the sealed treatment is 55-60°C, and the initial pressure is 80-90% of the atmospheric pressure. This step utilizes the volatility of ethanol itself to form a semi-dry state during the airing process. After the solvent is removed, the extract after the composite extraction is directly mixed with the particles. Deposited in a semi-dry system, when acetone is added, the acetone solubilizer in the extract can quickly dissolve to form a dissolving solution, and is evenly dispersed during the ultrasonic process. At this time, the sodium chloride and green coffee fine powder particles are evenly distributed in the acetone to form a homogenized structure. Based on the homogenized structure at this time and the water absorption of sodium chloride itself and the osmotic water absorption of acetone, the water-deficient and inactivated green coffee particles can further absorb water based on the acetone permeability, and acetone dissolution is proposed. In conjunction with the sealing care process, acetone is converted into a gaseous state to form a gaseous permeating gas, which greatly improves the dissolution efficiency, has excellent dissolution, and achieves secondary permeation dissolution;

[0008] Step 3, the slurry is kept at a constant temperature to obtain a concentrated solution and an acetone solution, and then the concentrated solution is filtered at a constant temperature and washed with an acetone solution to obtain an acetone leaching filtrate, the temperature of the constant temperature standing concentration is 30-40°C, the volume of the concentrated solution is 20-30% of the slurry, and the temperature of the constant temperature filtration is 20-30°C. This step utilizes the high volatility of acetone itself to release the acetone in the slurry, and the acetone solution is cooled and collected to obtain a recovered acetone solution and a concentrated acetone extract. During the constant temperature filtration process, sodium chloride and green coffee fine powder particles are removed at the same time, and the sodium chloride and green coffee fine powder particles are washed with the concentrated acetone solution;

[0009] Step 4, after concentrating the acetone leaching filtrate to dryness, adding distilled water, and adjusting the pH to 6-6.5 to obtain an acid solution; then directly pouring the acid solution into XAD-16 macroporous resin for adsorption treatment to obtain a lost liquid, and eluting the macroporous resin to obtain a caffeine eluate; the concentration temperature is 40-50° C., and acetone is recovered; the concentration after adding distilled water is 200-400 g / L, the pH is adjusted by hydrochloric acid, the mass ratio of the resin to the acid solution is 1:20-30, the elution is carried out by ethanol aqueous solution, and the volume proportion of ethanol in the ethanol aqueous solution is 1:20-30. The ethanol aqueous solution used for elution is 5-10 times the mass of the resin; the acetone leaching filtrate is concentrated to dryness in this step, and the acetone can be recovered for use in step 2; the addition of distilled water can convert the leaching solution from the acetone solvent into a water solvent, and the pH is adjusted to acidic by hydrochloric acid, and then placed in XAD-16 macroporous resin for adsorption treatment to remove caffeine in the acid solution, so that the caffeine content in the lost liquid does not exceed 5%, and the elution method releases the caffeine adsorbed by the XAD-16 macroporous resin to obtain a caffeine eluate;

[0010] Step 5, freeze-drying the lost liquid to obtain frozen particles, which are then placed in ether for low-temperature ultrasonic treatment for 20-50 minutes, and filtering to obtain fine powder particles and a filtrate, wherein the freeze-drying temperature is -20°C; the mass ratio of the frozen particles to ether is 1:5-8, the temperature of the low-temperature ultrasonic treatment is 5-10°C, and the ultrasonic frequency is 50-70kHz. In this step, the distilled water is removed by freeze-drying to achieve the purpose of drying, and chlorogenic acid particles containing caffeine are obtained; the chlorogenic acid particles are placed in ether, and the insolubility of ether in chlorogenic acid and the solubility of ether in caffeine can be used to The caffeine in the entire system is completely removed, and at the same time, the low-temperature ultrasound method can heat the frozen particles to form a certain amount of dissolved matter release, and open the particles in the high-frequency oscillation to release the caffeine inside the particles, and dissolve it in ether to achieve excellent caffeine removal effect, and after filtration, the chlorogenic acid particles with caffeine removed are obtained; in this treatment process, the amount of ether used is much greater than the mass of the frozen particles and much greater than the caffeine content. Based on its own usage, the ether can completely dissolve the caffeine, and cooperate with the vibration dispersion of the ultrasonic treatment to achieve the effect of completely releasing caffeine; the fine powder particles are chlorogenic acid.

[0011] Step 6, mixing the filtrate and the eluent to obtain a caffeine solution, concentrating it for 2-4 hours, and then freeze-drying it to obtain a caffeine by-product, wherein the concentration treatment adopts a reduced pressure treatment, and the temperature of the reduced pressure distillation is 50-60° C., the pressure is 60-70% of the atmospheric pressure, and the freeze-drying temperature is -20° C. In this step, the caffeine solution is treated by a concentration treatment method to remove ethanol and ether, and the entire solution is concentrated and converted into a caffeine aqueous solution; the caffeine aqueous solution is freeze-dried to achieve caffeine recovery.

[0012] It can be seen from the above description that the present invention has the following advantages:

[0013] 1. The present invention solves the problem of caffeine contained in chlorogenic acid, and realizes the gradient removal of caffeine by combining resin adsorption and solvent, and realizes the caffeine removal effect by combining the solubility difference between chlorogenic acid and caffeine.

[0014] 2. The present invention uses sodium chloride as a water-absorbing inactivating agent and a grinding agent to form the refinement and inactivation release of green coffee bean particles, achieve the effects of salt extraction and alcohol extraction, and realize the preliminary extraction of coffee beans.

[0015] 3. The present invention uses acetone as a solvent, and forms acetone dissolution and osmotic dissolution under ultrasonic and sealing treatment to achieve a secondary acetone dissolution effect. At the same time, acetone is used to dissolve the previous dissolution product secondary to achieve the dissolution and separation of the extract. DETAILED DESCRIPTION

[0016] The present invention is described in detail with reference to the embodiments, but no limitation is imposed on the claims of the present invention.

[0017] Example 1

[0018] A method for preparing caffeine-free chlorogenic acid comprises the following steps:

[0019] Step 1, refining green coffee beans into particles, then adding them into sodium chloride-ethanol colloid and stirring evenly, and forming a homogeneous colloid after wet ball milling; the green coffee beans are formed into fine powder particles by mechanical crushing, the mass ratio of sodium chloride to ethanol in the sodium chloride-ethanol colloid is 1:1, the mass ratio of green coffee beans to sodium chloride is 10:1, and the stirring speed is 1000r / min; the temperature of wet ball milling is 30°C, and the ball milling pressure is 0.5MPa;

[0020] Step 2, the homogenized colloid is allowed to stand and air-dry until it is semi-dry, then acetone is added and low-temperature ultrasonic treatment is performed for 20 minutes, sealed for 2 hours, and naturally cooled to obtain a slurry, wherein the standing temperature is 30°C, the concentration of the ultrasonic treatment is 30g / L, the temperature of the low-temperature ultrasonic treatment is 5°C, the ultrasonic frequency is 50kHz, the temperature of the sealed treatment is 55°C, and the initial pressure is 80% of the atmospheric pressure;

[0021] Step 3, the slurry is kept at a constant temperature and concentrated to obtain a concentrated solution and an acetone solution, and then the concentrated solution is filtered at a constant temperature and washed with an acetone solution to obtain an acetone leaching filtrate, wherein the temperature of the constant temperature and concentration is 30° C., the volume of the concentrated solution is 20% of the slurry, and the temperature of the constant temperature filtration is 20° C.;

[0022] Step 4, after concentrating the acetone leaching filtrate to dryness, adding distilled water, and adjusting the pH to 6 to obtain an acid solution; then directly pouring the acid solution into XAD-16 macroporous resin for adsorption treatment to obtain a lost liquid, and eluting to obtain a caffeine eluate; the concentration temperature is 40° C., and the acetone solution is recovered; the concentration after adding distilled water is 200 g / L, the pH is adjusted by hydrochloric acid, the mass ratio of the resin to the acid solution is 1:20, the elution is carried out by ethanol aqueous solution, and the volume proportion of ethanol in the ethanol aqueous solution is 70%, and the ethanol aqueous solution used for the elution is 5 times the mass of the resin;

[0023] Step 5, freeze-drying the lost liquid to obtain frozen particles, then placing it in ether and subjecting it to low-temperature ultrasonic treatment for 20-50 minutes, repeatedly washing and filtering to obtain fine powder particles and filtrate, wherein the freeze-drying temperature is -20°C; the mass ratio of the frozen particles to the ether is 1:5, the low-temperature ultrasonic treatment temperature is 5°C, and the ultrasonic frequency is 50kHz;

[0024] Step 6, mixing the filtrate and the eluate to obtain a caffeine solution, and concentrating the solution for 2 hours, and then freeze-drying the solution to obtain a caffeine by-product. The concentration process is carried out under reduced pressure, and the temperature of the reduced pressure distillation is 50° C., the pressure is 70% of the atmospheric pressure, and the freeze-drying temperature is -20° C.

[0025] The product of this example is a light green powder, wherein the purity of chlorogenic acid is 98.3%, no caffeine component is detected, and the product yield is 5.1%.

[0026] Example 2

[0027] A method for preparing caffeine-free chlorogenic acid comprises the following steps:

[0028] Step 1, refining green coffee beans into particles, then adding them into sodium chloride-ethanol colloid and stirring evenly, and forming a homogeneous colloid after wet ball milling; the green coffee beans are formed into fine powder particles by mechanical crushing, the mass ratio of sodium chloride to ethanol in the sodium chloride-ethanol colloid is 1:2, the mass ratio of green coffee beans to sodium chloride is 10:3, and the stirring speed is 2000r / min; the temperature of wet ball milling is 50°C, and the ball milling pressure is 0.9MPa;

[0029] Step 2, the homogenized colloid is allowed to stand and air-dry until it is semi-dry, then acetone is added and low-temperature ultrasonic treatment is performed for 30 minutes, sealed for treatment for 3 hours, and naturally cooled to obtain a slurry, wherein the standing temperature is 40°C, the concentration of the ultrasonic treatment is 50g / L, the temperature of the low-temperature ultrasonic treatment is 10°C, the ultrasonic frequency is 70kHz, the temperature of the sealed treatment is 60°C, and the initial pressure is 90% of the atmospheric pressure;

[0030] Step 3, the slurry is kept at a constant temperature and concentrated to obtain a concentrated solution and an acetone solution, and then the concentrated solution is filtered at a constant temperature and washed with an acetone solution to obtain an acetone leaching filtrate, wherein the temperature of the constant temperature and concentration is 40° C., the volume of the concentrated solution is 30% of the slurry, and the temperature of the constant temperature filtration is 30° C.;

[0031] Step 4, after concentrating the acetone leaching filtrate to dryness, adding distilled water, and adjusting the pH to 6.5 to obtain an acid solution; then directly pouring the acid solution into XAD-16 macroporous resin for adsorption treatment to obtain a lost liquid, and eluting to obtain a caffeine eluate; the concentration temperature is 50° C., and the acetone solution is recovered; the concentration after adding distilled water is 400 g / L, the pH is adjusted by hydrochloric acid, the mass ratio of the resin to the acid solution is 1:30, the elution is carried out by ethanol aqueous solution, and the volume proportion of ethanol in the ethanol aqueous solution is 80%, and the ethanol aqueous solution used for the elution is 10 times the mass of the resin;

[0032] Step 5, freeze-drying the lost liquid to obtain frozen particles, then placing it in ether for low-temperature ultrasonic treatment for 50 minutes, filtering to obtain a filtrate of fine powder particles, wherein the freeze-drying temperature is -20°C; the mass ratio of the frozen particles to the ether is 1:8, the low-temperature ultrasonic treatment temperature is 10°C, and the ultrasonic frequency is 70kHz;

[0033] Step 6, mixing the filtrate and the eluate to obtain a caffeine solution, and concentrating the solution for 4 hours, and then freeze-drying the solution to obtain a caffeine by-product. The concentration process is carried out under reduced pressure, and the temperature of the reduced pressure distillation is 60° C., the pressure is 60% of the atmospheric pressure, and the freeze-drying temperature is -20° C.

[0034] The product of this example is a light green powder, wherein the purity of chlorogenic acid is 99.1%, no caffeine component is detected, and the product yield is 5.5%.

[0035] Example 3

[0036] A method for preparing caffeine-free chlorogenic acid comprises the following steps:

[0037] Step 1, refining green coffee beans into particles, then adding them into sodium chloride-ethanol colloid and stirring evenly, and forming a homogeneous colloid after wet ball milling; the green coffee beans are formed into fine powder particles by mechanical crushing, the mass ratio of sodium chloride to ethanol in the sodium chloride-ethanol colloid is 1:2, the mass ratio of green coffee beans to sodium chloride is 10:2, and the stirring speed is 1500r / min; the temperature of wet ball milling is 40°C, and the ball milling pressure is 0.7MPa;

[0038] Step 2, the homogenized colloid is allowed to stand and air-dry until it is half dry, then acetone is added and low-temperature ultrasonic treatment is performed for 25 minutes, sealed for treatment for 3 hours, and naturally cooled to obtain a slurry, wherein the standing temperature is 35°C, the concentration of the ultrasonic treatment is 40g / L, the temperature of the low-temperature ultrasonic treatment is 8°C, the ultrasonic frequency is 60kHz, the temperature of the sealed treatment is 60°C, and the initial pressure is 85% of the atmospheric pressure;

[0039] Step 3, the slurry is kept at a constant temperature and concentrated to obtain a concentrated solution and an acetone solution, and then the concentrated solution is filtered at a constant temperature and washed with an acetone solution to obtain an acetone leaching filtrate, wherein the temperature of the constant temperature and concentration is 35° C., the volume of the concentrated solution is 25% of the slurry, and the temperature of the constant temperature filtration is 25° C.;

[0040] Step 4, after concentrating the acetone leaching filtrate to dryness, adding distilled water, and adjusting the pH to 6.5 to obtain an acid solution; then directly pouring the acid solution into XAD-16 macroporous resin for adsorption treatment to obtain a lost liquid, and eluting to obtain a caffeine eluate; the concentration temperature is 45° C., and the acetone solution is recovered; the concentration after adding distilled water is 300 g / L, the pH is adjusted by hydrochloric acid, the mass ratio of the resin to the acid solution is 1:25, the elution uses an ethanol aqueous solution, and the volume proportion of ethanol in the ethanol aqueous solution is 75%, and the ethanol aqueous solution used for the elution is 8 times the mass of the resin;

[0041] Step 5, freeze-drying the lost liquid to obtain frozen particles, then placing it in ether and subjecting it to low-temperature ultrasonic treatment for 40 minutes, filtering it to obtain a filtrate of fine powder particles, wherein the freeze-drying temperature is -20°C; the mass ratio of the frozen particles to the ether is 1:7, the low-temperature ultrasonic treatment temperature is 8°C, and the ultrasonic frequency is 60kHz;

[0042] Step 6, mixing the filtrate and the eluate to obtain a caffeine solution, and concentrating the solution for 3 hours, and then freeze-drying the solution to obtain a caffeine by-product. The concentration process is carried out under reduced pressure, and the temperature of the reduced pressure distillation is 55° C., the pressure is 65% of the atmospheric pressure, and the freeze-drying temperature is -20° C.

[0043] The product of this example is a light green powder, wherein the purity of chlorogenic acid is 98.7%, no caffeine component is detected, and the product yield is 5.3%.

[0044] It is understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A method for preparing caffeine-free chlorogenic acid, characterized in that: The steps include: Step 1, grinding green coffee beans into particles, adding them into sodium chloride-ethanol colloid solution and stirring them evenly, and forming a homogeneous colloid through wet ball milling; the green coffee beans are mechanically crushed to form fine powder particles; Step 2, leaving the homogenized colloid to stand and air-dry until it is half dry, then adding acetone and ultrasonically treating it at low temperature for 20-30 minutes, sealing it for 2-3 hours, and cooling it naturally to obtain a slurry; Step 3, concentrating the slurry at a constant temperature to obtain a concentrated solution and an acetone solution, and then filtering the concentrated solution at a constant temperature and washing with an acetone solution to obtain an acetone elution filtrate; Step 4, after the acetone leaching filtrate is concentrated to dryness, distilled water is added, and the pH is adjusted to 6-6.5 to obtain an acid solution; the acid solution is then directly poured into XAD-16 macroporous resin for adsorption treatment to obtain a lost liquid, and caffeine eluate is obtained after elution; Step 5, freeze-drying the lost liquid to obtain frozen particles, then placing them in ether for low-temperature ultrasonic treatment for 20-50 minutes, filtering to obtain fine powder particles and a filtrate, wherein the fine powder particles are chlorogenic acid; Step 6, mixing the filtrate and the eluate to obtain a caffeine solution, concentrating the solution for 2-4 hours, and then freeze-drying the solution to obtain a caffeine byproduct; The mass ratio of sodium chloride to ethanol in the sodium chloride-ethanol gel in step 1 is 1:1-2, the mass ratio of green coffee beans to sodium chloride is 10:1-3, and the stirring speed is 1000-2000r / min; the temperature of the wet ball milling treatment is 30-50°C, and the ball milling pressure is 0.5-0.9MPa; The temperature of the standing in step 2 is 30-40°C, the concentration of the ultrasonic treatment is 30-50g / L, the temperature of the low-temperature ultrasonic treatment is 5-10°C, the ultrasonic frequency is 50-70kHz, the temperature of the sealing treatment is 55-60°C, and the initial pressure is 80-90% of the atmospheric pressure; The temperature of the constant temperature static concentration in step 3 is 30-40°C, the volume of the concentrate is 20-30% of the slurry, and the temperature of the constant temperature filtration is 20-30°C; The concentration temperature in step 4 is 40-50° C., and the acetone solution is recovered; the concentration after adding distilled water is 200-400 g / L, the pH is adjusted by hydrochloric acid, the mass ratio of the resin to the acid solution is 1:20-30, the elution is carried out by ethanol aqueous solution, and the volume proportion of ethanol in the ethanol aqueous solution is 70-80%, and the ethanol aqueous solution used for elution is 5-10 times the mass of the resin; The freeze-drying temperature in step 5 is -20°C; the mass ratio of the frozen particles to ether is 1:5-8; the temperature of the low-temperature ultrasonic treatment is 5-10°C, and the ultrasonic frequency is 50-70kHz; The concentration treatment in step 6 adopts a reduced pressure treatment, and the temperature of the reduced pressure treatment is 50-60°C, the pressure is 60-70% of the atmospheric pressure, and the freeze-drying temperature is -20°C.