Preparation method for high-purity natural VC acerola cherry extract

Abstract

A preparation method for a high-purity natural VC acerola cherry extract, comprising the steps of: homogenization treatment of acerola cherry, solid-liquid separation, enzymolysis, desalination, decolorization, membrane separation, drying and the like. An acerola cherry extract product having a high purity (≥40%) and a high VC content can be prepared.

Description

A preparation method of high-purity natural VC acerola cherry extract Technical Field

[0001] The invention discloses a preparation method of a high-purity natural VC acerola cherry extract, belonging to the field of food technology. Background Art

[0002] Acerola cherry, commonly known as Indian cherry, is native to tropical America and is considered the best source of natural VC. It is the fruit with the highest natural VC content to date, containing 1 to 4.5% natural VC, which is 35 times that of lemon, 17 times that of strawberry, and 11 times that of guava. It is truly the "King of Vitamin C". Therefore, research on the extraction and development of natural VC from acerola cherry is of great value.

[0003] Currently, fresh fruit is usually used as raw material, and the natural VC therein is separated by extraction or adsorption separation to prepare acerola cherry extract, in which the VC content is about 20%, and is used as a raw material in the field of food and health food.

[0004] There are many acerola cherry extract products on the market, but all suffer from several drawbacks. First, the primary specification for VC content is 20%, with no acerola cherry extract exceeding 40% VC. Second, due to lax production and processing controls and the susceptibility of VC to oxidation, the color of these products is too dark, mostly yellow or light pink, making them difficult to use. Third, due to the complex composition of acerola cherry and the low extraction and enrichment ratio, the flavor of these products is not pure and can have off-flavors, making them difficult to use.

[0005] Summary of the Invention

[0006] In order to overcome the above-mentioned technical problems existing in the prior art, the technical problem to be solved by the present invention is to use acerola cherry as raw material, through cold pressing, enzymatic hydrolysis, desalination, decolorization, membrane separation, drying and other processes, to prepare acerola cherry extract product with high purity (≥40%) VC content, and provide a preparation process flow of high-purity natural VC acerola cherry extract.

[0007] A method for preparing a high-purity natural VC acerola cherry extract, characterized in that the VC content of the high-purity natural VC acerola cherry extract prepared by the preparation method is ≥40%.

[0008] As a preference, step (1) homogenization of acerola cherries

[0009] Take frozen acerola cherry fruit, add a certain proportion of purified water, homogenize it through a colloid mill under nitrogen protection, and extract it at a suitable temperature to obtain a homogeneous mixture rich in vitamin C;

[0010] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0011] The mixture liquid extracted in step (1) is passed into a separation device (plate and frame filter, horizontal screw centrifuge, disc centrifuge, etc.) to separate and obtain a clear liquid that meets the turbidity requirements;

[0012] Step (3) Enzymatic hydrolysis of the extract

[0013] Add food-grade compound enzyme preparation to the extracted clear solution for treatment, and control the temperature and time for enzymatic hydrolysis reaction;

[0014] Step (4) Decolorization of the enzymatic hydrolyzate

[0015] Decolorize the enzymatic hydrolyzate by passing it through activated carbon or diatomaceous earth, control the color index of the feed solution, and control the color index of the feed solution by the specific absorbance index to obtain the decolorized feed solution, which requires Brix 5% and the specific absorbance value at 370nm not exceeding 3;

[0016] Step (5) Polymer membrane separation

[0017] The decolorized liquid is passed through a polymer membrane separation system with a specific molecular weight cut-off to intercept target substances within a certain molecular weight range, and the permeate and retentate are collected separately;

[0018] Step (6) Preparation of high-purity natural VC dry powder

[0019] The retentate and permeate are fed into a spray drying tower for drying for a certain period of time, and the high-purity natural VC dry powder obtained after drying is collected.

[0020] As a preference, step (1) homogenization of acerola cherries

[0021] 5-10 g of frozen fresh acerola cherry fruit is taken, crushed with a grinder, passed through a 100-mesh sieve, added with purified water in a ratio of 1:1 to 1:15, homogenized with a colloid mill under nitrogen protection, and extracted at 20-50° C. to obtain a homogeneous mixture rich in vitamin C.

[0022] Preferably, step (2) solid-liquid separation of the vitamin C-rich mixture

[0023] The mixture liquid extracted in step (1) enters a separation device, is filtered with a 200-mesh filter, and is centrifuged at 3000-5000 r / min for 5-10 minutes to remove the precipitate, and a clear liquid that meets the turbidity requirements is separated.

[0024] Preferably, the enzymatic hydrolysis of the extract in step (3)

[0025] A food-grade complex enzyme preparation is added to the clear liquid obtained by extraction, and the ratio of pectinase to cellulase is 1:1 to 1:5 for treatment. The enzyme dosage of each group is 2 to 5% (the ratio of the mass of the enzyme to the mass of the clear liquid). Enzymolysis is carried out at a pH of 4 to 6 and a temperature of 30 to 50° C. for 1 to 3 hours, and then cooled to room temperature.

[0026] As a preference, in step (4), decolorization of the enzymatic hydrolysate

[0027] Decolorize the enzymatic hydrolyzate through activated carbon to control the color index of the liquid;

[0028] Activated carbon pretreatment activation process flow: granular activated carbon → 0.5-1 mol / L HCl solution → hot deionized water → filter → dry (100-120°C, 8-9h) → cool to room temperature for use; effect of activated carbon addition amount on decolorization effect of enzymatic hydrolyzate: take 10-20g of pretreated activated carbon, add it to the enzymatic hydrolyzate at a ratio of 5g / 100mL to 30g / 100mL, stir and decolorize in a constant temperature water bath at 70-90°C for 50-70min, cool to room temperature, centrifuge at 3000-5000r / min for 20-30min, filter, remove the activated carbon, and collect the decolorized liquid.

[0029] The advantages of the present invention are that the activated carbon has a developed microporous structure and super strong adsorption performance, some coloring substances in the enzymatic hydrolyzate are in a dissociated state in the solution, and the surface of the activated carbon also has multiple functional groups. When this substance with an active surface comes into contact with the enzymatic hydrolyzate, due to the effect of surface energy, the solute gathers on the solid-liquid surface, resulting in adsorption, the coloring substances are adsorbed, and the decolorization effect is obvious.

[0030] As a preference, step (5) polymer membrane separation

[0031] Before installing the membrane core, flush the system with deionized water, and then drain the water after it is clean; then install the HPS-100 ultrafiltration membrane core into the membrane tube, and then flush it with deionized water for 30 to 50 minutes to wash away the protective agent in the membrane assembly; after the storage tank is drained, pass the decolorized liquid through the membrane separation system to directionally retain the target substance, turn on the system, set the molecular weight cutoff to 10,000 to 30,000 Da, and the pressure to 0 to 0.4 MPa. After the system stabilizes, collect the permeate and retentate separately; after the membrane separation is completed, flush with deionized water for 10 to 15 minutes to drain the residual liquid in the circuit, then circulate and wash with a large amount of deionized water, then switch to membrane cleaning agent for cleaning for 30 to 40 minutes, and finally rinse repeatedly with a large amount of deionized water until the pH of the solution is neutral; when not in use, fill the membrane core with 1 to 2% H2O2 solution and store it in a sealed container at 3 to 4°C.

[0032] Preferably, the membrane separation system device comprises a tube body and a filter element, the tube body is provided with a through hole, the filter element passes through the through hole and slides into the tube body, and further comprises a clamping mechanism, a collecting device, an air jet device and a filtering device, the clamping mechanism is evenly mounted on the filter element, a plurality of groups of grooves are provided on the clamping mechanism, the connecting ends of the plurality of filtering devices are respectively connected to the clamping mechanism through the corresponding grooves, a threaded hole is provided at the bottom end of the tube body, the connecting end of the collecting device passes through the threaded hole and is threadedly connected to the tube body, a working chamber is provided in the collecting device, and the air jet device is evenly mounted in the working chamber;

[0033] The jet device also includes a copper tube, a universal joint, a sleeve, a fixed block and a spring. A penetration hole is provided in the working chamber. The copper tube passes through the penetration hole and is fixed to the collection bottle. The output end of the universal joint is connected to the input end of the copper tube, and the output end of the sleeve is connected to the input end of the universal joint. Multiple groups of slide grooves are provided in the sleeve, and multiple groups of fixed blocks pass through the corresponding slide grooves and are slidably connected to the sleeve. Multiple groups of springs are evenly installed on the corresponding fixed blocks.

[0034] Preferably, the clamping mechanism further comprises a chuck, a pin and a knob, the multiple sets of chucks are provided with pin holes, the multiple sets of chucks are hinged through the pin holes, the connecting ends of the multiple sets of pins are connected to the bottom ends of the corresponding chucks, the tube body is provided with multiple sets of pin grooves, the multiple sets of pin grooves are matched with rotary holes, and the multiple sets of knobs are respectively passed through the corresponding rotary holes and the corresponding pin grooves for threaded connection;

[0035] The collecting device also includes an end cover, a clamp, an adjusting knob and a collecting bottle. The end cover passes through a threaded hole and is threadedly connected to the tube body. The output ends of multiple sets of clamps are connected to the connecting ends of the end cover. Multiple sets of reamed holes are provided on the collecting bottle. Multiple sets of clamps pass through corresponding reamed holes and are rotatably connected to the collecting bottle. Multiple sets of adjusting knobs pass through corresponding reamed holes and are threadedly connected to corresponding clamps and the collecting bottle.

[0036] Preferably, the filtering device also includes cleaning cotton, tightening blocks and clustering blocks. Multiple groups of clustering blocks are respectively installed in corresponding grooves. The connecting ends of multiple groups of cleaning cotton are respectively connected to the output ends of corresponding clustering blocks. Multiple groups of chucks are provided with tightening holes. The tightening blocks pass through the multiple groups of tightening holes and the multiple groups of chucks for threaded connection.

[0037] Preferably, a membrane separation device for extracting plant active substances of the present invention further includes a screw, a support rod and a filter screen. The support rod is provided with an axial hole, and the copper tube passes through the axial hole and is slidably connected to the support rod. The support rod is provided with a screw hole, and the screw passes through the screw hole and is threadedly connected to the support rod. The filter screen is evenly installed on the support rod.

[0038] During the process of cleaning the ultrafiltration device, the clamping mechanism is rotated to clamp the filter device. During this process, the tube body is switched to a cleaning state by rotating the collection device, and the air pipe is clamped to the jet device. The filter element is cleaned by the combination of jet and water flow through the filter device. During this process, wastewater flows into the collection device for centralized discharge, thereby improving the convenience and work efficiency of equipment cleaning, which is more conducive to the extraction of plant active substances.

[0039] As a preference, step (6) preparation of high-purity natural VC dry powder

[0040] Before spraying, soluble starch, maltodextrin, and β-cyclodextrin are added to the liquid to be spray-dried as alternative drying aids. The ratio of the retentate and permeate to the alternative drying aids is 5:2 to 9:5, respectively. The feed concentration is 8 to 20%, the inlet air temperature is 140 to 180°C, the outlet air temperature is 50 to 70°C, the peristaltic pump speed is 300 to 500 r / min, the retentate and permeate are introduced into a spray drying tower for drying for 30 to 50 minutes, and the high-purity natural VC dry powder obtained after drying is collected.

[0041] The feeding speed of the existing technology is too slow, and there is no wall hanging and caking. Due to the slow liquid feeding speed, the final powder collection rate is greatly reduced. The amount of sample fed is too large, resulting in the nozzle being unable to effectively atomize it, unable to dry quickly, and a large amount of caking occurs.

[0042] The advantage of adopting the present invention is that during the entire processing process, due to the addition of a drying aid, the final powder yield is relatively high, and as the drying aid increases, the quality of the obtained powder also increases. As the inlet air temperature of the spray dryer increases, the powder collection rate of the system also increases accordingly. At the same time, the inlet air temperature of the spray dryer directly determines the speed and quality of powder particle formation. Sufficient drying can ensure that the obtained powder particles do not stick to the wall or agglomerate. When the inlet air temperature is low, a large amount of wall sticking phenomenon forms in the spray dryer, and the obtained powder particles also agglomerate in large pieces. As the inlet air temperature rises, when it rises to a higher temperature, the wall sticking phenomenon is greatly reduced, the yield is correspondingly increased, the water evaporation is also greatly increased, and the quality of the dry powder is also improved. When the inlet air temperature rises to a high temperature, there is basically no wall sticking phenomenon in the spray dryer, and the agglomeration phenomenon in the final product is also completely suppressed.

[0043] By adopting the present invention, the product produced by this process has the advantages of high content, pure flavor and light color, greatly improves product quality, reduces application difficulty, has a high yield, and is very suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a flow chart of the preparation process of a high-purity natural VC acerola cherry extract;

[0045] FIG2 is a schematic structural diagram of a membrane separation system device according to the present invention;

[0046] FIG3 is a partial enlarged structural schematic diagram of the membrane separation system device A of the present invention;

[0047] FIG4 is a partial enlarged structural schematic diagram of a membrane separation system device B of the present invention;

[0048] FIG5 is a partial enlarged structural schematic diagram of a membrane separation system device C of the present invention;

[0049] Markings in the accompanying drawings: 1. tube body; 2. filter element; 3. through hole; 4. clamping mechanism; 5. collecting device; 6. jet device; 7. filtering device; 8. groove; 9. threaded hole; 10. working chamber; 401. chuck; 402. pin; 403. knob; 404. pin hole; 405. pin slot; 406. rotating hole; 701. cleaning cotton; 702. tightening block; 703. clustering block; 704. tightening hole; 501. end cover; 502. clamp; 503. adjusting knob; 504. collecting bottle; 505. reaming; 601. copper tube; 602. universal joint; 603. sleeve; 604. fixing block; 605. spring; 606. through hole; 607. slide; 11. screw; 12. support rod; 13. filter screen; 14. shaft hole; 15. screw hole. DETAILED DESCRIPTION

[0050] Example 1

[0051] Step (1) Homogenization of Acerola Cherry

[0052] 5 g of frozen fresh acerola cherry fruit was crushed with a grinder, passed through an 80-mesh sieve, added with purified water at a ratio of 1:5, homogenized with a colloid mill under nitrogen protection, and extracted at 20°C to obtain a homogenous mixture rich in vitamin C;

[0053] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0054] The mixture liquid extracted in step (1) is passed into a separation device, filtered with a 150-mesh filter, centrifuged at 3000 r / min for 5 min to remove the precipitate, and a clear liquid that meets the turbidity requirements is obtained;

[0055] Step (3) Enzymatic hydrolysis of the extract

[0056] A food-grade compound enzyme preparation was added to the extracted supernatant, with the ratio of pectinase to cellulase being 1:1. The enzyme dosage of each group was 2% (the ratio of the mass of the enzyme to the mass of the supernatant). The enzyme hydrolysis was carried out at a pH of 4 and a temperature of 30°C for 1 hour, and then cooled to room temperature.

[0057] Step (4) Decolorization of the enzymatic hydrolyzate

[0058] Activated carbon pretreatment and activation process flow: granular activated carbon → 0.5 mol / L HCl solution → hot deionized water → filter → dry (100°C, 8 h) → cool to room temperature for use; take 10 g of pretreated activated carbon and add it to the enzymatic hydrolyzate at a ratio of 5 g / 100 mL, stir and decolorize in a 70°C constant temperature water bath for 50 min, cool to room temperature, centrifuge at 3000 rpm for 20 min, filter to remove the activated carbon, and collect the decolorized liquid;

[0059] Step (5) Polymer membrane separation

[0060] Before installing the membrane core, flush the system with deionized water. After draining the storage tank, pass the decolorized liquid through the membrane separation system. Set the molecular weight cut-off to 10,000 Da and the pressure to 0.2 MPa. After the system stabilizes, collect the permeate and retentate separately.

[0061] Step (6) Preparation of high-purity natural VC dry powder

[0062] The ratio of the retentate and permeate to the alternative drying aid was 5:2, the feed concentration was 8%, the inlet air temperature was 140°C, the outlet air temperature was 50°C, the peristaltic pump speed was 300 r / min, and the retentate and permeate were fed into a spray drying tower for drying for 30 minutes, and the high-purity natural VC dry powder obtained after drying was collected.

[0063] Example 2

[0064] Step (1) Homogenization of Acerola Cherry

[0065] 6 g of frozen fresh acerola cherry fruit was crushed with a grinder, passed through an 80-mesh sieve, added with purified water in a ratio of 1:8, homogenized with a colloid mill under nitrogen protection, and extracted at 30°C to obtain a homogeneous mixture rich in vitamin C;

[0066] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0067] The mixture liquid extracted in step (1) is passed into a separation device, filtered with a 150-mesh filter, centrifuged at 3500 r / min for 6 minutes to remove the precipitate, and separated to obtain a clear liquid that meets the turbidity requirements;

[0068] Step (3) Enzymatic hydrolysis of the extract

[0069] A food-grade compound enzyme preparation was added to the extracted supernatant, with the ratio of pectinase to cellulase being 1:2. The enzyme dosage for each group was 3% (the ratio of the mass of the enzyme to the mass of the supernatant). The enzyme hydrolysis was carried out at a pH of 4.5 and a temperature of 35°C for 1 hour, and then cooled to room temperature.

[0070] Step (4) Decolorization of the enzymatic hydrolyzate

[0071] Activated carbon pretreatment and activation process flow: granular activated carbon → 0.6 mol / L HCl solution → hot deionized water → filter → dry (105°C, 8 h) → cool to room temperature for use; take 10-20 g of pretreated activated carbon and add it to the enzymatic hydrolyzate at a ratio of 15 g / 100 mL, stir and decolorize in a 75°C constant temperature water bath for 55 min, cool to room temperature, centrifuge at 4000 rpm for 25 min, filter to remove the activated carbon, and collect the decolorized liquid;

[0072] Step (5) Polymer membrane separation

[0073] Before installing the membrane core, flush the system with deionized water. After draining the storage tank, pass the decolorized liquid through the membrane separation system. Set the molecular weight cut-off to 15,000 Da and the pressure to 0.2 MPa. After the system stabilizes, collect the permeate and retentate separately.

[0074] Step (6) Preparation of high-purity natural VC dry powder

[0075] The ratio of the retentate and permeate to the alternative drying aid was 7:3, the feed concentration was 12%, the inlet air temperature was 150°C, the outlet air temperature was 55°C, the peristaltic pump speed was 350 r / min, and the retentate and permeate were fed into a spray drying tower for drying for 35 minutes, and the high-purity natural VC dry powder obtained after drying was collected.

[0076] Example 3

[0077] Step (1) Homogenization of Acerola Cherry

[0078] 8 g of frozen acerola cherry fruit was crushed with a grinder, passed through a 100-mesh sieve, added with purified water at a ratio of 1:10, homogenized with a colloid mill under nitrogen protection, and extracted at 40°C to obtain a homogenous mixture rich in vitamin C;

[0079] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0080] The mixture liquid extracted in step (1) is passed into a separation device, filtered with a 200-mesh filter, centrifuged at 45,000 r / min for 8 minutes to remove the precipitate, and separated to obtain a clear liquid that meets the turbidity requirements;

[0081] Step (3) Enzymatic hydrolysis of the extract

[0082] A food-grade compound enzyme preparation was added to the extracted supernatant, with the ratio of pectinase to cellulase being 1:4. The enzyme dosage of each group was 4% (the ratio of the mass of the enzyme to the mass of the supernatant). The enzyme hydrolysis was carried out at a pH of 5 and a temperature of 40°C for 2 hours, and then cooled to room temperature.

[0083] Step (4) Decolorization of the enzymatic hydrolyzate

[0084] Activated carbon pretreatment and activation process flow: granular activated carbon → 0.8 mol / L HCl solution → hot deionized water → filter → dry (115°C, 9 h) → cool to room temperature for use; take 18 g of pretreated activated carbon and add it to the enzymatic hydrolyzate at a ratio of 20 g / 100 mL, stir and decolorize in a constant temperature water bath at 85°C for 65 min, cool to room temperature, centrifuge at 4500 rpm for 28 min, filter to remove the activated carbon, and collect the decolorized liquid;

[0085] Step (5) Polymer membrane separation

[0086] Before installing the membrane core, flush the system with deionized water. After draining the storage tank, pass the decolorized liquid through the membrane separation system. Set the molecular weight cut-off to 20,000 Da and the pressure to 0.3 MPa. After the system stabilizes, collect the permeate and retentate separately.

[0087] As shown in Figures 2 to 5, a membrane separation device for extracting plant active substances of the present invention includes a tube body 1 and a filter element 2. A through hole 3 is provided in the tube body 1, and the filter element 2 passes through the through hole 3 and slides into the tube body 1. It also includes a clamping mechanism 4, a collecting device 5, an air jet device 6 and a filtering device 7. The clamping mechanism 4 is evenly installed on the filter element 2. The clamping mechanism 4 is provided with multiple groups of grooves 8. The connecting ends of the multiple groups of filtering devices 7 are respectively connected to the clamping mechanism 4 through the corresponding grooves 8. The bottom end of the tube body 1 is provided with a threaded hole 9. The connecting end of the collecting device 5 passes through the threaded hole 9. It is threadedly connected to the tube body 1, and a working chamber 10 is provided in the collecting device 5, and the jet device 6 is evenly installed in the working chamber 10; in the process of cleaning the ultrafiltration device, the clamping mechanism is rotated to clamp the filter device. During this process, the tube body is switched to a cleaning state by rotating the collecting device, and the air pipe is clamped to the jet device. The filter element is cleaned by the jet and the ultrafiltration device. During this process, the wastewater flows into the collecting device for centralized discharge, thereby improving the convenience of equipment cleaning, thereby improving the working efficiency of the equipment and increasing practicality.

[0088] The clamping mechanism also includes a chuck 401, a pin 402 and a knob 403. Pin holes 404 are provided on multiple groups of chucks 401. Multiple groups of chucks 401 are hinged through the pin holes 404. The connecting ends of multiple groups of pins 402 are connected to the bottom ends of the corresponding chucks 401. Multiple groups of pin grooves 405 are provided on the tube body 1. Rotary holes 406 are provided on multiple groups of pin grooves 405. Multiple groups of knobs 403 are threaded through the corresponding rotary holes 406 and the corresponding pin grooves 405 respectively. In the process of clamping the filter device, the pins and pin grooves are buckled together. When the filter element is inserted into the filter device and in the process of cleaning the filter device, the knob is turned to loosen the multiple groups of chucks, and the chucks are rotated to unfold them, so as to improve the convenience of clamping the equipment, thereby improving the working efficiency of the equipment and increasing practicality.

[0089] The filtering device also includes cleaning cotton 701, tightening blocks 702 and clustering blocks 703. Multiple groups of clustering blocks 703 are respectively installed in corresponding grooves 8. The connecting ends of multiple groups of cleaning cotton 701 are respectively connected to the output ends of corresponding clustering blocks 703. Multiple groups of chucks 401 are provided with tightening holes 704. The tightening blocks 702 pass through the multiple groups of tightening holes 704 and are threadedly connected to the multiple groups of chucks 401. In the process of cleaning the filter element, the filter element is scraped by the shape of the multiple groups of clustering blocks. In this process, the impurities in the filter element are collected in conjunction with the cleaning cotton, so as to improve the cleaning stability of the equipment, thereby improving the working efficiency of the equipment and increasing practicality.

[0090] The collecting device also includes an end cap 501, a clamp 502, an adjusting knob 503 and a collecting bottle 504. The end cap 501 is threadedly connected to the tube body 1 through the threaded hole 9, and the output ends of multiple groups of clamps 502 are connected to the connecting ends of the end cap 501. The collecting bottle 504 is provided with multiple groups of reamed holes 505. Multiple groups of clamps 502 are respectively passed through the corresponding reamed holes 505 and are rotatably connected to the collecting bottle 504. Multiple groups of adjusting knobs 503 are respectively passed through the corresponding reamed holes 505 and are threadedly connected to the corresponding clamps 502 and the collecting bottle 504. In the process of collecting impurities from the filter element, the end cap is rotated to leak out the bottom of the tube body, the collecting bottle is rotated to remove it from the end cap, and the collecting bottle is rotated to connect it to the tube body, so as to collect impurities from the filter element, thereby improving the cleanliness of the equipment, thereby improving the working efficiency of the equipment, and thus increasing practicality.

[0091] The jet device also includes a copper tube 601, a universal joint 602, a sleeve 603, a fixed block 604 and a spring 605. A through hole 606 is provided in the working chamber 10. The copper tube 601 passes through the through hole 606 and is fixedly mounted on the collecting bottle 504. The output end of the universal joint 602 is connected to the input end of the copper tube 601, and the output end of the sleeve 603 is connected to the input end of the universal joint 602. A plurality of groups of slide grooves 607 are provided in the sleeve 603. A plurality of groups of fixed blocks 604 pass through corresponding slide grooves 607 and are slidably connected to the sleeve 603. A plurality of groups of springs 605 are evenly installed on the corresponding fixed blocks 604. In the process of cleaning the filter element, the jet device such as the rubber hose of the air path device is placed in the sleeve, the tube body is fixed by the fixed block and the spring, the angle of the device is adjusted by rotating the universal joint, and the filter element is sprayed with water by the copper tube in cooperation with the ultrafiltration device to clean the filter element, thereby improving the cleaning convenience of the device, thereby improving the working efficiency of the device and increasing the practicality.

[0092] A membrane separation device for extracting plant active substances of the present invention also includes a screw 11, a support rod 12 and a filter 13. The support rod 12 is provided with an axial hole 14, and the copper tube 601 passes through the axial hole 14 and is slidably connected to the support rod 12. The support rod 12 is provided with a screw hole 15, and the screw 11 passes through the screw hole 15 and is threadedly connected to the support rod 12. The filter 13 is evenly installed on the support rod 12; in the process of collecting impurities, the clean impurities automatically fall into the collection bottle, the support rod is fixed by rotating the screw, and the passing wastewater is filtered by the filter on the support rod, and the impurities are collected in a centralized manner, thereby improving the convenience of cleaning the equipment, thereby improving the working efficiency of the equipment and increasing practicality.

[0093] The present invention relates to a membrane separation device for extracting plant active substances. When working, the clamping mechanism is rotated to clamp the filter device. During this process, the collection device is rotated to switch the tube body to a clean state, the trachea is clamped to the jet device, and the jet and ultrafiltration device are used to pass water to clean the filter element. During this process, waste water flows into the collection device for centralized discharge. The pin and the pin groove are buckled together, and the filter element is inserted into the filter device. During the cleaning process of the filter device, the knob is rotated to loosen the multiple sets of clamps, and the clamps are rotated to expand them. The filter element is cleaned by the shape of the multiple sets of cluster blocks. Scrape. During this process, use cleaning cotton to collect impurities on the filter element, rotate the end cap to leak out the bottom of the tube body, rotate the collecting bottle to remove it from the end cap, rotate the collecting bottle to connect it to the tube body, place the rubber hose of the air path device and other jet equipment into the sleeve, fix the tube body with the fixing block and spring, adjust the angle of the equipment by rotating the universal joint, spray water through the copper tube and the ultrafiltration device to clean the filter element, and the clean impurities automatically fall into the collecting bottle, fix the support rod by rotating the screw, filter the passing wastewater through the filter screen on the support rod, and collect impurities in a centralized manner.

[0094] Step (6) Preparation of high-purity natural VC dry powder

[0095] The ratio of the retentate and permeate to the alternative drying aid was 8:3, the feed concentration was 16%, the inlet air temperature was 170°C, the outlet air temperature was 65°C, the peristaltic pump speed was 450 r / min, and the retentate and permeate were fed into a spray drying tower for drying for 45 minutes, and the high-purity natural VC dry powder obtained after drying was collected.

[0096] Example 4

[0097] Step (1) Homogenization of Acerola Cherry

[0098] 10 g of frozen acerola cherry fruit was crushed with a grinder, passed through a 100-mesh sieve, added with purified water at a ratio of 1:15, homogenized with a colloid mill under nitrogen protection, and extracted at 50° C. to obtain a homogenous mixture rich in vitamin C;

[0099] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0100] The mixture liquid extracted in step (1) is passed into a separation device, filtered with a 200-mesh filter, centrifuged at 5000 r / min for 10 min to remove the precipitate, and separated to obtain a clear liquid that meets the turbidity requirements;

[0101] Step (3) Enzymatic hydrolysis of the extract

[0102] A food-grade compound enzyme preparation was added to the extracted supernatant, with the ratio of pectinase to cellulase being 1:5. The enzyme dosage of each group was 5% (the ratio of the mass of the enzyme to the mass of the supernatant). The enzyme hydrolysis was carried out at a pH of 6 and a temperature of 50°C for 3 hours, and then cooled to room temperature.

[0103] Step (4) Decolorization of the enzymatic hydrolyzate

[0104] Activated carbon pretreatment and activation process flow: granular activated carbon → 1 mol / L HCl solution → hot deionized water → filter → dry (120°C, 9 h) → cool to room temperature for use; take 20g of pretreated activated carbon and add it to the enzymatic hydrolyzate at a ratio of 30g / 100mL, stir and decolorize in a 90°C constant temperature water bath for 70min, cool to room temperature, centrifuge at 5000r / min for 30min, filter to remove the activated carbon, collect the decolorized liquid, and control the color index of the liquid by specific absorbance index to obtain the decolorized liquid with a Brix of 5% and a specific absorbance value of no more than 3 at 370nm;

[0105] Step (5) Polymer membrane separation

[0106] Before installing the membrane core, flush the system with deionized water. After draining the storage tank, pass the decolorized liquid through the membrane separation system. Set the molecular weight cut-off to 30,000 Da and the pressure to 0.4 MPa. After the system stabilizes, collect the permeate and retentate separately.

[0107] Step (6) Preparation of high-purity natural VC dry powder

[0108] The ratio of the retentate and permeate to the alternative drying aid was 9:5, respectively. The feed concentration was 20%, the inlet air temperature was 180°C, the outlet air temperature was 70°C, the peristaltic pump speed was 500 r / min, and the retentate and permeate were fed into a spray drying tower for drying for 50 minutes. The high-purity natural VC dry powder obtained after drying was collected.

[0109] Comparative Example 1

[0110] Step (1) Homogenization of Acerola Cherry

[0111] 5 g of frozen fresh acerola cherry fruit was crushed with a grinder, passed through an 80-mesh sieve, added with purified water at a ratio of 1:5, homogenized with a colloid mill under nitrogen protection, and extracted at 20°C to obtain a homogenous mixture rich in vitamin C;

[0112] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0113] The mixture liquid extracted in step (1) is passed into a separation device, filtered with a 150-mesh filter, centrifuged at 3000 r / min for 5 min to remove the precipitate, and a clear liquid that meets the turbidity requirements is obtained;

[0114] Step (3) Enzymatic hydrolysis of the extract

[0115] A food-grade compound enzyme preparation was added to the extracted supernatant, with the ratio of pectinase to cellulase being 1:1. The enzyme dosage of each group was 2% (the ratio of the mass of the enzyme to the mass of the supernatant). The enzyme hydrolysis was carried out at a pH of 4 and a temperature of 30°C for 1 hour, and then cooled to room temperature.

[0116] Step (4) Decolorization of the enzymatic hydrolyzate

[0117] Activated carbon pretreatment and activation process flow: granular activated carbon → 0.5 mol / L HCl solution → hot deionized water → filter → dry (100°C, 8 h) → cool to room temperature for use; take 10 g of pretreated activated carbon and add it to the enzymatic hydrolyzate at a ratio of 5 g / 100 mL, stir and decolorize in a 70°C constant temperature water bath for 50 min, cool to room temperature, centrifuge at 3000 rpm for 20 min, filter to remove the activated carbon, and collect the decolorized liquid;

[0118] Step (5) Polymer membrane separation

[0119] Before installing the membrane core, flush the system with deionized water. After draining the storage tank, pass the decolorized liquid through the membrane separation system. Set the molecular weight cut-off to 10,000 Da and the pressure to 0.2 MPa. After the system stabilizes, collect the permeate and retentate separately.

[0120] Step (6) Preparation of high-purity natural VC dry powder

[0121] The ratio of the retentate and permeate to the alternative drying aid was 5:2, the feed concentration was 8%, the inlet air temperature was 140°C, the outlet air temperature was 50°C, the peristaltic pump speed was 300 r / min, and the retentate and permeate were fed into a spray drying tower for drying for 30 minutes, and the high-purity natural VC dry powder obtained after drying was collected.

[0122] Comparative Example 2

[0123] Step (1) Homogenization of Acerola Cherry

[0124] 5 g of frozen fresh acerola cherry fruit was crushed with a grinder, passed through an 80-mesh sieve, added with purified water at a ratio of 1:5, homogenized with a colloid mill under nitrogen protection, and extracted at 20°C to obtain a homogenous mixture rich in vitamin C;

[0125] Step (2) Solid-liquid separation of vitamin C-rich mixture

[0126] The mixture liquid extracted in step (1) is passed into a separation device, filtered with a 150-mesh filter, centrifuged at 3000 r / min for 5 min to remove the precipitate, and a clear liquid that meets the turbidity requirements is obtained;

[0127] Step (3) Enzymatic hydrolysis of the extract

[0128] A food-grade compound enzyme preparation was added to the extracted supernatant, with the ratio of pectinase to cellulase being 1:1. The enzyme dosage of each group was 2% (the ratio of the mass of the enzyme to the mass of the supernatant). The enzyme hydrolysis was carried out at a pH of 4 and a temperature of 30°C for 1 hour, and then cooled to room temperature.

[0129] Step (4) Decolorization of the enzymatic hydrolyzate

[0130] Activated carbon pretreatment and activation process flow: granular activated carbon → 0.5 mol / L HCl solution → hot deionized water → filter → dry (100°C, 8 h) → cool to room temperature for use; take 10 g of pretreated activated carbon and add it to the enzymatic hydrolyzate at a ratio of 5 g / 100 mL, stir and decolorize in a 70°C constant temperature water bath for 50 min, cool to room temperature, centrifuge at 3000 rpm for 20 min, filter to remove the activated carbon, collect the decolorized liquid, and control the color index of the liquid by specific absorbance index to obtain the decolorized liquid with a Brix of 5% and a specific absorbance value of no more than 3 at 370 nm;

[0131] Step (5) Polymer membrane separation

[0132] Before installing the membrane core, flush the system with deionized water. After draining the storage tank, pass the decolorized liquid through the membrane separation system. Set the molecular weight cut-off to 10,000 Da and the pressure to 0.2 MPa. After the system stabilizes, collect the permeate and retentate separately.

[0133] Step (6) Preparation of high-purity natural VC dry powder

[0134] The ratio of the retentate and permeate to the alternative drying aid was 5:2, the feed concentration was 8%, the inlet air temperature was 140°C, the outlet air temperature was 50°C, the peristaltic pump speed was 300 r / min, and the retentate and permeate were fed into a spray drying tower for drying for 30 minutes, and the high-purity natural VC dry powder obtained after drying was collected.

[0135] The concentrated powder compositions obtained in Examples 1 to 4 and Comparative Example Products 1 and 2 were tested. The specific testing methods are as follows:

[0136] Calculation of pollen collection rate:

[0137] Powder collection rate = collected dry powder / mass of solid material before spray drying × 100%

[0138] Sensory evaluation

[0139] A batch of VC dry powder was selected for appearance, taste and flavor evaluation.

[0140] Vitamin antioxidant activity assay

[0141] Take 100 ml of the extract, add 0.01-0.05% Vc, mix well to obtain a test sample, take 60 μl of the liquid from the test sample, dilute it to a 100 ml volumetric flask, and remove 2 ml to determine its DPPH free radical scavenging rate. Take 2 ml of the test sample, dilute it to a 100 ml volumetric flask, and remove 200 μl to determine its hydroxyl free radical scavenging rate. Take 1 ml of the test sample, dilute it to a 100 ml volumetric flask, and remove 200 μl to determine its total antioxidant capacity.

[0142] Table 1 Test results of powder collection rate

[0143] As shown in Table 1, the temperature, rotation speed and feed concentration all affect the final product yield. Too high or too low will result in a reduced powder collection rate. Among them, Example 3 has the highest yield and Comparative Example 1 has the lowest yield.

[0144] Table 2 Sensory evaluation test results

[0145] As shown in Table 2, the sensory evaluation of the VC dry powder obtained in Examples 1-4 was good, while that in the comparative example was poor.

[0146] Table 3 DPPH free radical scavenging test results

[0147] Table 4 Hydroxyl radical scavenging rate test results

[0148] Table 5 Total antioxidant capacity test results

[0149] It can be seen from Tables 3, 4 and 5 that different concentrations of vitamins can improve the antioxidant properties to varying degrees. The free radical scavenging rate of the extract shows an upward trend with increasing addition amount, showing a synergistic effect. VC has a synergistic effect on the free radical scavenging ability of the extract after extraction. Different concentrations of vitamins can improve the antioxidant properties of the extract after extraction to varying degrees; Example 3 has the largest scavenging rate, the rotation speed and temperature are moderate, and there is no wall hanging phenomenon and less powder collection, so the obtained dry powder VC has a higher purity; Comparative Example 1 has the smallest scavenging rate. Due to the low rotation speed and low temperature, the extract cannot be fully dried and the water cannot be discharged in the first time, forming a large number of sticky block objects, which ultimately greatly reduces the powder collection rate of the dry powder, resulting in a lower purity of the final VC and a poor scavenging rate.

[0150] This specific embodiment is merely an explanation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for preparing a high-purity natural VC acerola cherry extract, characterized in that: The VC content of the high-purity natural VC acerola cherry extract prepared by the preparation method is ≥40%.

2. A method for preparing the high-purity natural VC acerola cherry extract according to claim 1, characterized in that: Step (1) Homogenization of Acerola Cherry Take frozen acerola cherry fruit, add a certain proportion of pure water, homogenize it through a colloid mill under nitrogen protection, and extract it at a suitable temperature to obtain a homogenous mixture rich in vitamin C; Step (2) Solid-liquid separation of vitamin C-rich mixture The mixed liquid extracted in step (1) is fed into a separation device to separate a clear liquid that meets the turbidity requirement; Step (3) Enzymatic hydrolysis of the extract Adding a food-grade compound enzyme preparation to the extracted clear liquid for treatment, and controlling the temperature and time for enzymatic hydrolysis; Step (4) Decolorization of the enzymatic solution Decolorize the enzymatic hydrolyzate by passing it through activated carbon or diatomaceous earth to control the color index of the feed liquid; Step (5) Polymer membrane separation The decolorized liquid is passed through a polymer membrane separation system with a specific molecular weight cut-off to intercept target substances within a certain molecular weight range, and the permeate and the retentate are collected separately; Step (6) Preparation of high-purity natural VC dry powder The retentate and the permeate are placed in a spray drying tower for drying for a certain period of time, and the high-purity natural VC dry powder obtained after drying is collected.

3. A method for preparing the high-purity natural VC acerola cherry extract as claimed in claim 2, characterized in that: Step (1) Homogenization of Acerola Cherry Take 5-10g of frozen fresh acerola cherry fruit, grind it with a grinder, pass it through an 80-100 mesh sieve, add purified water in a ratio of 1:1-1:15, homogenize it with a colloid mill under nitrogen protection, and extract it at 20-50°C to obtain a homogenous mixture rich in vitamin C.

4. A method for preparing the high-purity natural VC acerola cherry extract as claimed in claim 3, characterized in that: Step (2) Solid-liquid separation of vitamin C-rich mixture The mixed liquid extracted in step (1) enters a separation device, is filtered with a 150-200 mesh filter, centrifuged at 3000-5000 r / min for 5-10 minutes to remove the precipitate, and separates to obtain a clear liquid that meets the turbidity requirements.

5. A method for preparing the high-purity natural VC acerola cherry extract as claimed in claim 4, characterized in that: Step (3) Enzymatic hydrolysis of the extract A food-grade compound enzyme preparation is added to the clear liquid obtained by extraction, and the ratio of pectinase to cellulase is 1:1 to 1:5 for treatment. The enzyme dosage of each group is 2 to 5% (the ratio of the mass of the enzyme to the mass of the clear liquid). The enzymolysis is carried out at a pH of 4 to 6 and a temperature of 30 to 50° C. for 1 to 3 hours, and then cooled to room temperature.

6. A method for preparing the high-purity natural VC acerola cherry extract as claimed in claim 5, characterized in that: Step (4) Decolorization of the enzymatic solution The enzymatic hydrolysate is decolorized by activated carbon to control the color index of the feed liquid; Activated carbon pretreatment activation process flow: granular activated carbon → 0.5-1 mol / L HCl solution → hot deionized water → filter → dry (100-120°C, 8-9h) → cool to room temperature for use; Effect of activated carbon addition on the decolorization effect of enzymatic hydrolyzate: take 10-20g of pretreated activated carbon, add it to the enzymatic hydrolyzate at a ratio of 5g / 100mL-30g / 100mL, stir and decolorize in a constant temperature water bath at 70-90°C for 50-70min, cool to room temperature, centrifuge at 3000-5000r / min for 20-30min, filter, remove the activated carbon, and collect the decolorized liquid.

7. A method for preparing the high-purity natural VC acerola cherry extract according to claim 6, characterized in that: Step (5) Polymer membrane separation Before installing the membrane core, rinse the system with deionized water, and then drain the water after it is cleaned; then install the HPS-100 ultrafiltration membrane core into the membrane tube, and then rinse it with deionized water for 30 to 50 minutes to wash away the protective agent in the membrane assembly; after the storage tank is drained, pass the decolorized feed liquid through the membrane separation system device to intercept the target substance in a directional manner, turn on the system, set the molecular weight cutoff to 10,000 to 30,000 Da, and the pressure to 0 to 0.4 MPa, and collect the permeate and retentate respectively after the system is stable; after the membrane separation is completed, rinse with deionized water for 10 to 15 minutes, drain the residual liquid in the circuit, and then use a large amount of deionized water for cyclic washing, and then change to membrane cleaning agent for cleaning for 30 to 40 minutes, and finally rinse repeatedly with a large amount of deionized water until the pH of the solution is neutral; when not in use, fill the membrane core with 1 to 2% H2O2 solution and seal it at 3 to 4°C for storage.

8. A method for preparing the high-purity natural VC acerola cherry extract according to claim 7, characterized in that: Step (6) Preparation of high-purity natural VC dry powder Before spraying, soluble starch, maltodextrin and beta-cyclodextrin are added to the liquid to be spray-dried as alternative drying aids, the ratio of the retentate and the permeate to the alternative drying aids is 5:2-9:5 respectively, the feed concentration is 8-20%, the inlet air temperature is 140-180°C, the outlet air temperature is 50-70°C, the peristaltic pump speed is 300-500r / min, the retentate and the permeate are introduced into a spray drying tower for drying, the drying time is 30-50min, and the high-purity natural VC dry powder obtained after drying is collected.

9. A method for preparing a high-purity natural VC acerola cherry extract as claimed in claim 7, characterized in that: The membrane separation system device comprises a tube body (1) and a filter element (2), wherein a through hole (3) is provided in the tube body (1), and the filter element (2) passes through the through hole (3) and slides into the tube body (1); the device is characterized in that it also comprises a clamping mechanism (4), a collecting device (5), an air jet device (6) and a filtering device (7), wherein the clamping mechanism (4) is evenly mounted on the filter element (2), a plurality of groups of grooves (8) are provided on the clamping mechanism (4), and the connecting ends of the plurality of groups of filtering devices (7) respectively pass through corresponding grooves (8) and are connected to the clamping mechanism (4), a threaded hole (9) is provided at the bottom end of the tube body (1), and the connecting end of the collecting device (5) passes through the threaded hole (9) and is threadedly connected to the tube body (1), a working chamber (10) is provided in the collecting device (5), and the air jet device (6) is evenly mounted in the working chamber (10); The jet device also includes a copper tube (601), a universal joint (602), a sleeve (603), a fixed block (604) and a spring (605). A through hole (606) is provided in the working chamber (10). The copper tube (601) passes through the through hole (606) and is fixedly mounted on the collecting bottle (504). The output end of the universal joint (602) is connected to the input end of the copper tube (601). The output end of the sleeve (603) is connected to the input end of the universal joint (602). A plurality of groups of slide grooves (607) are provided in the sleeve (603). The plurality of groups of fixed blocks (604) pass through corresponding slide grooves (607) and are slidably connected to the sleeve (603). The plurality of groups of springs (605) are evenly mounted on corresponding fixed blocks (604).

10. A method for preparing the high-purity natural VC acerola cherry extract according to claim 9, characterized in that: The clamping mechanism also includes a chuck (401), a pin (402) and a knob (403); the plurality of chucks (401) are each provided with a pin hole (404); the plurality of chucks (401) are hinged through the pin hole (404); the connection ends of the plurality of pins (402) are each connected to the bottom end of the corresponding chuck (401); the tube body (1) is provided with a plurality of pin grooves (405); the plurality of pin grooves (405) are each provided with a knob (406); the plurality of knobs (403) are respectively threadedly connected through the corresponding knob holes (406) and the corresponding pin grooves (405); The collecting device also includes an end cover (501), a clamp (502), an adjusting knob (503) and a collecting bottle (504); the end cover (501) passes through the threaded hole (9) and is threadedly connected to the tube body (1); the output ends of the plurality of clamps (502) are all connected to the connecting end of the end cover (501); the collecting bottle (504) is provided with a plurality of reaming holes (505); the plurality of clamps (502) respectively pass through the corresponding reaming holes (505) and are rotatably connected to the collecting bottle (504); and the plurality of adjusting knobs (503) respectively pass through the corresponding reaming holes (505) and are threadedly connected to the corresponding clamps (502) and the collecting bottle (504).

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