An extraction process for high-purity Eucommia ulmoides gum

Abstract

This invention belongs to the field of Eucommia ulmoides gum extraction technology, specifically relating to a high-purity Eucommia ulmoides gum extraction process. The invention uses fresh green leaves of Eucommia ulmoides or rehydrated dried leaves as raw materials. A rubbing machine is used to separate the leaf pulp and veins. The veins are then subjected to stepwise enzymatic hydrolysis with four types of biological enzymes, followed by washing with a natural soap powder solution, water washing, and centrifugation to obtain high-purity Eucommia ulmoides gum. The cuticle layer naturally present on the surface of Eucommia ulmoides leaves, which protects the plant and resists degradation of plant tissue by external biological enzymes, is damaged, broken, and peeled off after mechanical rubbing. This facilitates direct contact and enzymatic hydrolysis between the biological enzymes and the broken leaf vein tissue encapsulating the Eucommia ulmoides gum. Stepwise enzymatic hydrolysis with four types of enzymes further purifies and removes the leaf vein tissue, exposing the Eucommia ulmoides gum to the solution. Furthermore, the composition of the natural soap powder is highly similar to the polyisoprene structure of the Eucommia ulmoides gum, binding with the gum and causing it to hydrophilically expand and separate from the Eucommia ulmoides leaf residue, resulting in high-purity Eucommia ulmoides gum.

Description

Technical Field

[0001] This invention belongs to the field of Eucommia gum preparation technology, specifically relating to an extraction process for high-purity Eucommia gum. Background Technology

[0002] Eucommia gum is mainly found in the bark, fruit, and leaves of the Eucommia ulmoides tree. Specifically, the bark of the Eucommia ulmoides tree contains 11%–16% gum, the dried fruit containing kernels contains 12%, the dried leaves contain 2%–5%, and the bark of old, thin branches contains 10%. Although the gum content of Eucommia ulmoides leaves is much lower than that of the dried bark and dried fruit, the Eucommia ulmoides tree produces a small amount of fruit, while the leaves are abundant, resulting in a large base number and thus a relatively high total gum content.

[0003] Studies have found that the bark and pericarp of Eucommia ulmoides have complex structures. Eucommia gum is encapsulated by the periderm composed of the cork cambium and the inner cork layer, as well as the inner phloem. Therefore, the Eucommia gum growing in the cork cambium is not easy to extract, making the extraction process more difficult and costly. In contrast, the Eucommia gum in Eucommia ulmoides leaves is mainly concentrated in the veins. The main tissue of the leaves is mesophyll (75%), which does not contain gum. Although the veins have the function and structure of bark and contain a cork cambium, they are not significantly lignified. The thin, lignin-free young cork layer is easily degraded and dissolved in the enzymatic hydrolysate by highly active enzymes. Therefore, the extraction of Eucommia gum is less difficult, and the production cost is only one-fifth of that for extracting gum from bark and pericarp. Moreover, Eucommia ulmoides leaves are a renewable resource that can be used as an inexhaustible and high-quality raw material for extracting Eucommia gum.

[0004] However, the surface of Eucommia ulmoides leaves has a cuticle layer that protects the plant tissue and prevents erosion by external microorganisms. The presence of the cuticle layer blocks the degradation of Eucommia ulmoides leaf plant tissue by biological enzymes and hinders the bio-extraction of natural products from Eucommia ulmoides leaves, so it must be removed first.

[0005] Currently, the method of preparing Eucommia gum using Eucommia leaves as raw material has the following problems:

[0006] Firstly, sun-drying or oven-drying fresh Eucommia leaves facilitates storage. The resulting dried Eucommia leaves have a cuticle layer that adheres tightly to the plant tissue and is hydrophobic, making it difficult to remove by rubbing. If a rubbing machine is used to rub the dried Eucommia leaves to separate most of the leaf mesophyll tissue, this method requires either a long drying time or high-temperature drying, which increases extraction costs. Furthermore, when using dried Eucommia leaves, the cuticle layer of the leaf veins becomes thicker and more resistant to pressure due to water loss, thus increasing the difficulty of enzymatic hydrolysis and making it time-consuming, which is not conducive to the enzymatic extraction of Eucommia gum.

[0007] Secondly, using fresh green Eucommia leaves as raw material, directly crushing and breaking down the leaves, and then further enzymatically hydrolyzing them with biological enzymes, although this can achieve a more complete utilization of the active ingredients in the Eucommia leaves, the gum fibers are pulverized, the original properties and functions are severely lost, and the quality declines. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a process for extracting high-purity Eucommia ulmoides gum.

[0009] This invention provides a process for extracting high-purity Eucommia ulmoides gum, comprising the following steps:

[0010] (1) Pretreatment of Eucommia ulmoides leaves;

[0011] (2) The Eucommia ulmoides leaves that have been sorted and pretreated in (1) are rubbed using a rubbing separator. The rubbing causes the Eucommia ulmoides leaves to be deeply folded and curled into strips. The rubbing crushes the leaf pulp and breaks the leaf pulp cells, separating the leaf pulp from the gum-containing leaf veins until only Eucommia ulmoides leaf vein gum filaments remain. The remaining leaf vein gum filaments account for 22-28% of the raw material mass.

[0012] (3) The Eucommia ulmoides gum filaments obtained after kneading in (2) are subjected to stepwise continuous enzymatic hydrolysis using biological enzymes. The hydrolysate is filtered out to obtain residual solid Eucommia ulmoides gum filaments. The enzymatic hydrolysis sequence of the biological enzymes is as follows: lipase, pectinase, protease, cellulase.

[0013] (4) The residual Eucommia ulmoides gum filaments obtained in (3) were dissolved and cleaned using a natural soap powder aqueous solution;

[0014] (5) The Eucommia gum obtained in (4) is repeatedly shaken and washed with water, centrifuged and dried to obtain anhydrous Eucommia gum.

[0015] In step (1) above, when the Eucommia ulmoides leaves are fresh green leaves, the pretreatment operation is as follows: fresh green Eucommia ulmoides leaves are sorted and air-dried to remove dust.

[0016] In step (1) above, when the Eucommia ulmoides leaves are dried Eucommia ulmoides leaves, the pretreatment operation is as follows: the dried Eucommia ulmoides leaves are sorted, air-dried to remove dust, and then soaked in clean water to soak and expand the dried leaves. A large amount of water seeps into the leaves, making the dried leaves swollen, soft and loose, and then rubbed.

[0017] The raw material used in this invention is Eucommia ulmoides leaves. Harvesting and production begin in June, while most of the leaves are already old leaves when harvested in autumn. A large number of old fresh leaves must be processed by kneading in a short time without excessive crushing of the leaf pulp. The main reasons are: firstly, it helps to promote the dehydration and drying of the fresh green leaves for storage and stacking, so as to facilitate subsequent production; secondly, this operation can also prevent the cuticle layer on the surface of the fresh green Eucommia ulmoides leaves from becoming thick, hard, and hydrophobic after being spread out and dried, so that the cuticle layer covering the leaves is no longer easily crushed.

[0018] Therefore, in this invention, in order to better rub and break the cuticle layer on the surface of Eucommia ulmoides leaves, the large amount of fresh green leaves obtained for storage must be pre-treated by rubbing in a timely manner to make the Eucommia ulmoides leaves deeply folded and curled into strips. Furthermore, before enzymatic hydrolysis in a purification machine, the leaves are thoroughly rubbed to separate the leaf pulp and leaf veins, so as to reduce the workload of gum extraction and enzymatic hydrolysis.

[0019] In this invention, the dried Eucommia ulmoides leaves must be rehydrated before kneading. This involves soaking the dried Eucommia ulmoides leaves in clean water for a long time to allow them to expand and soften. The water penetrates into the leaves, making the cuticle and leaf pulp soft and loose. When kneaded with a kneading machine, the cuticle is more likely to fall off and break, which facilitates the release of Eucommia ulmoides gum.

[0020] In step (3), the weight of lipase and pectinase is 1.8-2.2% and the weight of protease and cellulase is 0.8-1.5% based on the weight of Eucommia ulmoides leaves.

[0021] Preferably, in (3), the amount of lipase and pectinase used is 2% of the weight of Eucommia ulmoides leaves.

[0022] Preferably, in (3), the amount of protease and cellulase used is 1% of the weight of Eucommia ulmoides leaves.

[0023] In this invention, the order in which biological enzymes are used to degrade the fibrous strands of Eucommia ulmoides leaf veins is based on the composition and structure of the Eucommia ulmoides leaf plant tissue, proceeding from the outside in. The working principles of each enzyme in step (3) above are as follows:

[0024] First, the cuticle of Eucommia ulmoides leaves is a fatty substance secreted by epidermal cells, the main component of which is a hydroxy fatty acid containing 16-18 carbons. Therefore, the addition of alkaline lipase can greatly destroy and degrade the cuticle and waxy components remaining after rubbing, breaking down the outermost barrier of Eucommia ulmoides leaves, which is beneficial for subsequent enzymatic hydrolysis. The addition of pectinase can degrade various pectins that are stuck together to form geometric three-dimensional tissue structures, and unravel various tissue structural units with different properties.

[0025] In addition, since various organs and tissues are the most active plant tissues, they contain a large number of plant metabolic enzymes and proteins as well as inactive structural proteins. The degradation and erosion of protein components disrupt the continuity of the original tissue and the binding state between structures, thereby pulverizing the plant tissue and eroding the geometric structure of the original tissue.

[0026] The reason for adding cellulase last is that after removing the plant tissue that encapsulates the Eucommia gum cells, only the white tissue tightly adhering to the Eucommia gum cell walls remains. Plant cell walls are mainly composed of cellulose, pectin, and hemicellulose. Since the plant was harvested that year, it does not contain lignin and can be hydrolyzed and destroyed by cellulase alone.

[0027] In step (4) above, the mass concentration of the natural soap powder aqueous solution is 4% to 8%, the water temperature during washing is 45 to 50°C, the washing is stirred at a speed of 30 to 40 rpm, and the washing time is 8 to 10 hours.

[0028] Preferably, in (5), the Eucommia ulmoides fibers are dehydrated and spun dry using an industrial centrifuge.

[0029] In step (4) of this invention, the Eucommia ulmoides gum filaments obtained after final enzymatic hydrolysis are cleaned with a natural soap powder aqueous solution. The main reason is that although the previous bio-enzymatic hydrolysis operation can separate the non-gumming plant tissues in the Eucommia ulmoides leaves from the Eucommia ulmoides gum and produce a large amount of plant residue, the hydrophobic long filament Eucommia ulmoides gum is very easy to entangle with the degraded residue in the hydrolysis solution, and the plant residue is wrapped and entangled in the gum filaments. Under the action of natural soap powder, the hydrophobic Eucommia ulmoides gum micelles can be spread out, further releasing the binding of the plant residue and realizing the separation of Eucommia ulmoides gum.

[0030] The natural soap powder used in this invention is made from vegetable oil fatty acid C. 17 H 35 The plant oil fatty acids generated by the saponification reaction of COOCH2 have long-chain unsaturated alkane chains and carbon-carbon double bonds in the carbon chain. They are highly similar in structure to the polyisoprene polymer of Eucommia ulmoides gum, and therefore the two have a high degree of affinity. Thus, the surface tension of Eucommia ulmoides gum bound to saponified oil decreases in aqueous solution, allowing it to spread and disperse freely. The plant residues trapped in it are no longer bound by the long filaments and gums, and disperse and settle at the bottom of the washing solution, thus achieving the separation of plant residues and purifying Eucommia ulmoides gum.

[0031] The inventors discovered in their research that using natural soap powder to clean Eucommia ulmoides gum filaments is more effective. Although common surfactants, such as sodium dodecyl sulfate, can also separate plant residues encased in the gum filaments to some extent, the degree of expansion of the Eucommia ulmoides gum filaments is limited. The main reason for this is that sodium dodecyl sulfate has a low alkyl chain, and its affinity with Eucommia ulmoides gum filaments is not as high as that of natural soap powder, which has a higher structural similarity. Therefore, the decrease in surface tension after sodium dodecyl sulfate is not as significant as that of natural soap powder.

[0032] In addition, natural soap powder is inexpensive, and using it for cleaning can significantly reduce production costs and allow the soap fibers to fully expand and remove any trapped residue.

[0033] Furthermore, the extraction and production process of high-purity Eucommia gum provided by the present invention includes the following steps:

[0034] (1) Fresh Eucommia ulmoides leaves are used as raw materials, and are selected and air-separated for dust removal;

[0035] (2) Use a rubbing separator to rub the pretreated fresh green leaves of Eucommia ulmoides in (1). First, make the Eucommia ulmoides leaves deeply folded and curled into strips. Then, rub the leaf pulp into pieces, break the leaf pulp cells, and separate the leaf pulp from the gum-containing leaf veins until the Eucommia ulmoides gum filaments are tangled into filaments. The remaining leaf vein gum filament clumps account for 22-28% of the raw material mass.

[0036] (3) The Eucommia ulmoides gum filaments obtained after kneading in (2) are subjected to stepwise enzymatic hydrolysis using biological enzymes. The hydrolysate is filtered out to obtain residual solid Eucommia ulmoides gum filaments. The biological enzymes are, in order: lipase, pectinase, protease, and cellulase. The weight of lipase and pectinase is 1.8-2.2% and the weight of protease and cellulase is 0.8-1.5% based on the weight of fresh Eucommia ulmoides leaves.

[0037] (4) The residual Eucommia ulmoides gum filaments obtained in (3) were washed with a natural soap powder aqueous solution. The water temperature during washing was 45-50℃. The mixture was stirred during washing at a speed of 30-40 rpm and the washing time was 8-10 hours.

[0038] (5) The Eucommia gum obtained in (4) is repeatedly shaken and washed with clean water, and then dehydrated and dried in an industrial centrifuge to obtain anhydrous Eucommia gum.

[0039] The beneficial effects of this invention are as follows:

[0040] (1) This invention uses fresh green leaves of Eucommia ulmoides or old leaves of Eucommia ulmoides after rehydration as raw materials. The leaf pulp without gum is removed by rubbing, and the cuticle layer on the soft leaf surface is removed. This is conducive to the full contact between the enzyme preparation and the Eucommia ulmoides plant tissue, and is conducive to further improving the purity of Eucommia gum extraction. The purity of Eucommia gum obtained by the method of this invention is as high as 98.94%, and the cost of enzymatic hydrolysis is low.

[0041] (2) In this invention, lipase is used to enzymatically hydrolyze the cuticle of the leaves that was not completely removed during rubbing. Under the action of lipase, the waxy components in the cuticle of the leaves can be enzymatically hydrolyzed, which is beneficial for the subsequent enzyme preparation to come into fuller contact with the eucommia gum contained in the leaves.

[0042] (3) In this invention, a natural soap powder solution is used to clean Eucommia gum. The carbon-carbon double bonds contained in the natural soap powder are highly similar to the structure of the polyisoprene polymer of Eucommia gum, so that Eucommia gum can freely spread and disperse in the soap powder solution. This allows the plant residues trapped in it to be no longer bound by the long filament gum clusters and dispersed and settled at the bottom of the cleaning solution, thus achieving the separation of plant residues and purifying Eucommia gum.

[0043] (4) In addition, the process of the present invention does not require drying of Eucommia ulmoides leaves, so there is no need for a large space for sun drying, nor is a high temperature required to dry the leaves, thus greatly reducing the extraction cost of Eucommia ulmoides gum. Attached Figure Description

[0044] Figure 1 This is a color diagram of the Eucommia ulmoides leaf pulp fragments obtained by kneading fresh Eucommia ulmoides leaves using a kneading machine in Embodiment 1 of the present invention.

[0045] Figure 2 This refers to the Eucommia ulmoides leaf vein gelatinous filaments obtained by kneading fresh Eucommia ulmoides leaves using a kneading machine in Embodiment 1 of the present invention;

[0046] Figure 3 This refers to the Eucommia ulmoides gum strands obtained by enzymatic hydrolysis with lipase and pectinase in Example 1 of the present invention.

[0047] Figure 4 This refers to the Eucommia ulmoides gum filaments obtained by enzymatic hydrolysis with protease and cellulase in Example 1 of the present invention;

[0048] Figure 5 The Eucommia ulmoides gum obtained in Example 1 of the present invention after washing with a natural soap powder solution;

[0049] Figure 6 The air-dried Eucommia ulmoides gum obtained in Example 1 of the present invention;

[0050] Figure 7 The purity test report of Eucommia ulmoides gum obtained in Example 1 of the present invention;

[0051] Figure 8 This is a color diagram of the Eucommia ulmoides leaf pulp fragments obtained by kneading dried Eucommia ulmoides leaves using a kneading machine in Comparative Example 1 of the present invention.

[0052] Figure 9 This refers to the green vein filaments of Eucommia ulmoides leaves obtained by rubbing dried Eucommia ulmoides leaves in Comparative Example 1 of the present invention.

[0053] Figure 10 This is the result of hand-rubbed Eucommia ulmoides leaves being hydrolyzed by lipase and pectinase in Comparative Example 1 of the present invention;

[0054] Figure 11 This is the result of hand-rubbed Eucommia ulmoides leaves being hydrolyzed by protease and cellulase in Comparative Example 1 of the present invention;

[0055] Figure 12 The hand-rubbed Eucommia ulmoides gum in Comparative Example 1 of the present invention after being washed with natural soap powder solution;

[0056] Figure 13 This is the hand-rubbed leaf-dried Eucommia ulmoides gum obtained in Comparative Example 1 of the present invention. Detailed Implementation

[0057] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0058] Example 1

[0059] (1) Take fresh Eucommia ulmoides leaves, select and wash them;

[0060] (2) Using a Eucommia ulmoides leaf rubbing and separating machine (the equipment disclosed in patent CN218689966U), the pre-treated Eucommia ulmoides leaves are rubbed to first cause deep folding and curling of the leaves into strips. Then, before being sent to the purification machine, the leaf pulp is crushed, the leaf pulp cells are broken, and the leaf pulp is separated from the gum-containing veins until the Eucommia ulmoides gum filaments are entangled into filament clusters. The remaining leaf vein gum filament clusters account for about 25% of the raw material mass, as shown in the attached figure. Figures 1-2 As shown;

[0061] (3) Add the approximately 300 kg of leaf vein gum filaments obtained after kneading in (2) to the enzymatic hydrolysis tank of the Eucommia gum enzymatic hydrolysis purification machine, and add biological enzymes for enzymatic hydrolysis. The specific operation is as follows:

[0062] S1 Lipase hydrolysis: First, add the first buffer solution to the hydrolysis tank. The first buffer solution is a citric acid and trisodium citrate buffer solution with a pH of 8.2. The amount of purified water added is 450 kg. Then, add 6 kg of lipase and continuously hydrolyze for 10 h at 36℃ and 26 rpm. Filter the hydrolysate to obtain the residual Eucommia ulmoides gum filaments after hydrolysis.

[0063] S2 pectinase hydrolysis: Add the second buffer solution (citric acid and trisodium citrate buffer solution with pH 3.8) to the residual Eucommia ulmoides gum filaments after S1 hydrolysis. Add 400 kg of purified water, then add 6 kg of pectinase, and continuously hydrolyze for 10 h at 50℃ and 28 rpm. Filter the hydrolysate to obtain the hydrolyzed residual Eucommia ulmoides gum filaments.

[0064] After stepwise enzymatic hydrolysis with the two enzymes mentioned above, the remaining Eucommia ulmoides gum strands are shown in the attached figure. Figure 3 As shown.

[0065] Since most of the plant tissue has been destroyed during the enzymatic hydrolysis process using lipase and pectinase, and the volume of the gum clumps has been significantly reduced, a second batch of 250 kg of gum clumps after pectinase hydrolysis is added to the purification tank to repeat the previous enzymatic hydrolysis.

[0066] Two batches of Eucommia ulmoides leaf vein filament bundles after enzymatic hydrolysis were unloaded from the self-unloading enzymatic hydrolysis purifier and transferred to a second self-unloading enzymatic hydrolysis purifier.

[0067] S3 protease hydrolysis: Add 400 kg of buffer solution III (pH 3.2) to the residual Eucommia ulmoides gum filaments after S2 hydrolysis. Then add 5 kg of protease and hydrolyze continuously at 45℃ and 30 rpm for 16 h. Filter the hydrolysate to obtain the hydrolyzed residual Eucommia ulmoides gum filaments.

[0068] S4 Cellulase hydrolysis: Add 300 kg of buffer solution IV (pH 6.4) to the residual Eucommia ulmoides gum filaments after S3 hydrolysis. Then add 3 kg of cellulase and hydrolyze continuously at 50℃ and 30 rpm for 16 h. Filter the hydrolysate to obtain the hydrolyzed residual Eucommia ulmoides gum filaments.

[0069] After the above four enzymatic hydrolysis steps, the condition of the Eucommia ulmoides gum filaments is as follows: Figure 4 As shown.

[0070] (4) Add 200 kg of clean water to the residual gum filaments obtained in (3), and wash continuously for 1 hour under neutral conditions at 50°C and 30 rpm. Collect the washing liquid in a solution tank, then add 300 kg of clean water and 10 kg of natural soap powder, and wash for 8 hours at 50°C and 35 rpm to obtain relatively pure Eucommia gum, as shown in the attached figure. Figure 5 As shown.

[0071] (5) The Eucommia ulmoides gum obtained in (4) was repeatedly shaken and washed with clean water, dehydrated and dried using an industrial centrifuge, and then washed with 200 kg of purified water at 50°C and 35 rpm for 1 hour to obtain anhydrous Eucommia ulmoides gum, as shown in the attached figure. Figure 6 As shown.

[0072] The extraction rate of Eucommia ulmoides gum obtained using the method of this invention is 96%. Furthermore, the purity of the obtained Eucommia ulmoides gum was tested by Fair Testing Technology (Tianjin) Co., Ltd., and a corresponding test report was provided, as attached. Figure 7 As shown, the purity of the Eucommia ulmoides extract obtained by the method of the present invention is 98.94%.

[0073] Appendix Figures 1-2 The results showed that after rubbing fresh Eucommia leaves, the resulting rubbed filaments were dark brown. This indicates that the cuticle of the fresh leaves is easily damaged by rubbing, and the green leaf tissue is exposed to air and oxidizes. The drug component of aucubin is oxidized to dark brown. Similarly, the rubbed leaf vein filaments also changed color, turning dark brown.

[0074] From the appendix Figure 3 The results show that using only lipase and pectinase to degrade the rubbed Eucommia gum filaments results in significant degradation. Since the raw Eucommia leaves are fresh, the cuticle layer on the surface of the fresh leaves is severely damaged and peeled off after being rubbed, squeezed, and rubbed. The leaf mesophyll loses the protection of the cuticle layer and turns dark brown, allowing the leaf mesophyll tissue to fully contact and be degraded by the enzymes. The Eucommia gum with yellow plant pigment attached is then better released in the enzymatic hydrolysate. However, the degree of enzymatic hydrolysis using only these two enzymes is limited. As shown in the figure, the veins of the Eucommia leaves are still clearly visible. Therefore, other enzyme preparations must be used for further enzymatic hydrolysis of the gum filaments.

[0075] When four specific biological enzymes are used for degradation, the eucommia gum in machine-kneaded tea leaves is almost completely released. Figure 4 It can also be seen that the filaments of Eucommia gum are tangled together, and the purification level is also improved.

[0076] After enzymatic hydrolysis, the eucommia gum is washed with a natural soap powder solution, such as... Figure 5-6 As shown, the yellow color of Eucommia gum is quite obvious, and there are no plant residues, powders, or other impurities in it, indicating that the purity of Eucommia gum has been greatly improved.

[0077] Examples 2-5

[0078] Based on Example 1, parameters such as the pH of the buffer solution and the amount of enzyme preparation added were adjusted respectively. The pH of the buffer solution and the amount of each enzyme preparation added in each example are shown in Table 1 below.

[0079] In the following examples, the methods for detecting the yield and purity of Eucommia ulmoides gum are as follows:

[0080] Eucommia gum yield (%) = mass of Eucommia gum filaments (kg) / mass of Eucommia raw material (kg);

[0081] Purity of Eucommia gum (%) = Mass of dry Eucommia gum (kg) / Mass of Eucommia gum filaments (kg);

[0082] Table 1 shows the parameter settings in Examples 2-5.

[0083]

[0084] Comparative Example 1

[0085] Unlike Example 1, (1) uses dried Eucommia ulmoides leaves as raw material and uses hand rubbing instead of a rubbing machine to rub the dried Eucommia ulmoides leaves. All other operations are the same as in Example 1.

[0086] (1) Use dried green Eucommia ulmoides leaves as raw material;

[0087] (2) Rub the dried Eucommia ulmoides leaves by hand to obtain fragments of dried Eucommia ulmoides leaves and coarse gum from the leaf veins, as shown in the attached image. Figures 8-9 As shown.

[0088] (3) Add the leaf vein gum filaments obtained after kneading in (2) to the enzymatic hydrolysis tank of the Eucommia gum enzymatic hydrolysis purification machine, and add biological enzymes for enzymatic hydrolysis. The enzymatic hydrolysis steps are the same as in Example 1.

[0089] The condition of the Eucommia ulmoides gum filaments after enzymatic hydrolysis by lipase and pectinase is shown in the attached figure. Figure 10 As shown in the attached figure, the condition of the Eucommia ulmoides gum filaments after enzymatic hydrolysis by protease and cellulase is as follows. Figure 11 As shown.

[0090] (4) The Eucommia ulmoides gum filaments obtained in (3) were washed and purified using a natural soap powder aqueous solution to obtain relatively pure Eucommia ulmoides gum, as shown in the attached image. Figure 12 As shown.

[0091] (5) The Eucommia ulmoides gum obtained in (4) is repeatedly shaken and washed with clean water, and then dried in a ventilated place to obtain anhydrous Eucommia ulmoides gum, as shown in the attached figure. Figure 13 As shown.

[0092] From the appendix Figures 8-9 As can be seen, compared with the dark brown Eucommia ulmoides powder obtained by rubbing fresh Eucommia ulmoides leaves in Example 1, the powder obtained by rubbing dried Eucommia ulmoides leaves by hand and the Eucommia ulmoides gum are both greenish-blue. Therefore, it can be proved that the cuticle layer on the surface of dried Eucommia ulmoides leaves is thick, strong and pressure resistant, and has not been damaged by rubbing. It still has a luster and can protect the leaf pulp from external oxidation.

[0093] Appendix Figure 10 The results showed that after hand-rubbing the dried leaves and then hydrolyzing them with lipase and pectinase, almost no exposed Eucommia gum could be observed. The possible reason is that hand-rubbing causes less damage to the cuticle of the dried Eucommia leaves. As a result, the fragments of the dried leaves are protected and blocked by the intact cuticle, making it difficult for biological enzymes to penetrate. Therefore, there are no obvious signs of degradation and erosion in the leaf mesophyll and vein tissues. The Eucommia gum in the petioles and veins is not fully exposed. The petioles and vein tissues with high gum content in the Eucommia leaves are intact, and the Eucommia gum filaments are still wrapped in these tissues and cannot be released. The efficiency of enzymatic hydrolysis is extremely low.

[0094] Appendix Figure 11 The results show that even after enzymatic hydrolysis with protease and cellulase, the artificially rubbed Eucommia ulmoides leaves, due to the barrier effect of the cuticle, are protected from external erosion by biological enzymes, preventing the degradation and erosion of leaf tissue. No exposed Eucommia ulmoides gum filaments are observed in the image, and a large amount of plant tissue remains on the gum filaments. This is in contrast to Example 1. Figure 4 This result undoubtedly confirms the crucial, important, and necessary role of rubbing in breaking down the cuticle layer on the leaf surface.

[0095] Furthermore, after hand-rubbed dried Eucommia leaves are sequentially enzymatically hydrolyzed by four enzymes, the cuticle layer prevents complete degradation by the enzymes. The cuticle layer and plant debris adhere to the Eucommia gum. Even after washing with a natural soap powder solution, the resulting Eucommia gum still contains a large amount of dark brown, difficult-to-separate Eucommia leaf fragments. Even after further repeated washing with water and drying, the Eucommia gum still has a high impurity content and low purity. (See attached image.) Figures 12-13 As shown.

[0096] Compared with Example 1, the Eucommia gum obtained in this comparative example has an extraction rate of 88% and a purity of 85.09%. The physicochemical properties and various functions of low-purity Eucommia gum are greatly reduced, and its use value is not high.

[0097] Comparative Example 2

[0098] Unlike Example 1, fresh Eucommia ulmoides leaves were used. In (2), the Eucommia ulmoides leaves were not rubbed and were directly enzymatically hydrolyzed. The yield of Eucommia ulmoides gum was 90% and the purity was 83.12%. Moreover, due to the low enzymatic hydrolysis efficiency of the enzyme preparation, the enzymatic hydrolysis time and consumption of the enzyme preparation were greatly increased, and the production cost increased by 60%.

[0099] Comparative Example 3

[0100] Unlike Example 1, fresh green leaves of Eucommia ulmoides were used. In (2), hand rubbing was used instead of a rubbing machine to rub the Eucommia ulmoides leaves. The yield of Eucommia ulmoides gum was 92% and the purity was 91.25%. This increased the labor cost, and the cost increased by nearly 40%.

[0101] Comparative Example 4

[0102] Unlike Example 1, (1) uses dried Eucommia ulmoides leaves as raw material. The leaves are directly rubbed and enzymatically hydrolyzed using a rubbing machine. The yield of Eucommia ulmoides gum is 88%, and the purity is 90.36%. Due to the thick cuticle and high hardness of the dried leaves, the enzymatic hydrolysis is more difficult, so the consumption of enzyme preparations is doubled, which in turn increases the production cost by 100%.

[0103] Comparative Example 5

[0104] Unlike Example 1, in (3), the four enzymes were directly mixed together and added to the gum filaments obtained in (2) for enzymatic hydrolysis. The hydrolysis temperature was 50°C, the pH was 4.8, and the hydrolysis time was 62 hours, with two 1-hour pauses in between. As a result, the yield of Eucommia gum was 86% and the purity was 78.09%.

[0105] Comparative Example 6

[0106] Unlike Example 1, (3) uses not only the four enzymes from Example 1 for stepwise enzymatic hydrolysis, but also alkaline xylanase and acidic xylanase for stepwise enzymatic hydrolysis, in order to further improve the purity of the extracted Eucommia gum. The specific operation is as follows:

[0107] First, 1% alkaline xylanase was used to enzymatically hydrolyze the solid xylan group in a sodium citrate buffer solution at pH 7.2 for 48 hours at 50°C and 32 rpm. After pouring out the hydrolysate, the enzyme was replaced with 1% acidic xylanase and enzymatically hydrolyzed in a sodium citrate buffer solution at pH 4.8 for 36 hours at 50°C and 28 rpm. The remaining steps were the same as in Example 1.

[0108] The yield of Eucommia gum was 96%, and the purity was 99.00%. However, due to the further increase in the depth of enzymatic hydrolysis and the increase in the types of enzymes, the cost of enzymatic hydrolysis increased by 160%.

[0109] Comparative Example 7

[0110] Compared with Example 1, in step (4), natural soap powder was not used for cleaning, and the extraction rate of Eucommia gum obtained was 95%, the purity was 72.30%, and the impurity content was very high.

[0111] The extraction rate and purity of Eucommia gum obtained from the above-mentioned comparative examples of the present invention were determined, as shown in Table 2 below.

[0112] Table 2 shows the extraction rate and purity of Eucommia ulmoides gum in Comparative Examples 1-7.

[0113]

[0114]

[0115] As can be seen from the data in the table above, in Comparative Example 1, using dried Eucommia ulmoides leaves as raw material and manually kneading the leaves, the extraction rate of Eucommia ulmoides gum was only 88%, and the purity was only 85.09%. The reasons for this phenomenon are as follows: on the one hand, compared with fresh leaves, the outer cuticle of dried Eucommia ulmoides leaves is thicker and harder, making it more difficult to break down, thus making it more difficult to extract the Eucommia ulmoides gum component; on the other hand, manual kneading is less effective than mechanical kneading.

[0116] In Comparative Example 2, fresh Eucommia ulmoides leaves were used, but without kneading, and enzymatic hydrolysis was performed directly. The yield of Eucommia ulmoides gum was low, only 90%, and the purity was also low, only 83.12%. This indicates that mechanical kneading also has a significant effect on improving the yield and purity of Eucommia ulmoides.

[0117] In Comparative Example 3, it can be seen that the yield of Eucommia gum was higher than that in Comparative Example 2 by 2 percentage points compared with that without kneading, and the purity also increased from 83.12% to 91.25%, which fully demonstrates the necessity of kneading.

[0118] In Comparative Example 4, using dried leaves as raw material, even after mechanical kneading, the yield of Eucommia gum was 88%, the purity was 90.36%, and the enzyme consumption doubled, resulting in a 100% increase in the final production cost. This indicates that kneading must be done promptly when the leaves are fresh.

[0119] In Comparative Example 5, although fresh green leaves were used as raw material and mechanical kneading was employed, the extraction rate and purity of Eucommia gum obtained by using mixed enzymatic hydrolysis of Eucommia leaves were not high. This was mainly due to the interaction between the mixed enzyme preparations. The optimal pH range and the most suitable temperature for the enzyme preparations to play their role were different. Therefore, the enzymatic hydrolysis effect of each enzyme was somewhat restricted at specific temperatures and pH levels, resulting in a low yield and purity of Eucommia gum.

[0120] In Comparative Example 6, fresh green leaves were used as raw material, and mechanical kneading was used as an aid. Alkaline xylanase and acid xylanase were added for further enzymatic hydrolysis. Although the extraction rate and purity of Eucommia gum were improved compared with Example 1, the production cost increased by 160%.

[0121] Comparative Example 8, based on Example 1, did not use natural soap powder solution for washing the obtained Eucommia gum. Obviously, the purity of Eucommia gum was only 72.30%, and the impurity content was relatively high.

Claims

1. A process for extracting high-purity Eucommia ulmoides gum, characterized in that, The steps include the following: (1) Pretreatment of Eucommia ulmoides leaves: When the Eucommia ulmoides leaves are fresh green leaves, the pretreatment is as follows: take fresh green Eucommia ulmoides leaves, sort them, and air-dry them to remove dust. When the Eucommia ulmoides leaves are dried Eucommia ulmoides leaves, the pretreatment is as follows: sort the dried Eucommia ulmoides leaves, air-dry them to remove dust, and then soak them in clean water to soak and expand them. A large amount of water seeps into the leaves, making them swollen, soft and loose, and then they are kneaded. (2) The Eucommia ulmoides leaves that have undergone pretreatment in (1) are kneaded using a kneading machine. First, the Eucommia ulmoides leaves are deeply folded and curled into strips. Then, the leaf pulp is crushed, the leaf pulp cells are broken, and the leaf pulp is separated from the gum-containing veins until the Eucommia ulmoides gum filaments are tangled into filament balls. The remaining leaf vein gum filament balls account for 22-28% of the raw material mass. (3) The Eucommia ulmoides gum filaments obtained after kneading in (2) are subjected to stepwise enzymatic hydrolysis using four biological enzymes. The hydrolysate is filtered out to obtain residual Eucommia ulmoides gum filaments. The order of enzymatic hydrolysis is: lipase, pectinase, protease, cellulase. (4) The residual Eucommia ulmoides gum filaments obtained in (3) were cleaned with a natural soap powder aqueous solution; (5) The Eucommia ulmoides gum obtained in (4) is repeatedly shaken and washed with clean water, centrifuged and dehydrated to obtain anhydrous Eucommia ulmoides gum.

2. The extraction process for high-purity Eucommia ulmoides gum as described in claim 1, characterized in that, In (3), based on the weight of Eucommia ulmoides leaves, the weight of lipase and pectinase is 1.8~2.2%, and the weight of protease and cellulase is 0.8~1.5%.

3. The extraction process for high-purity Eucommia ulmoides gum as described in claim 1, characterized in that, (4) The mass concentration of the natural soap powder aqueous solution is 4%~8%, the water temperature during washing is 45~50℃, the stirring is carried out during washing, the stirring speed is 30~40rpm, and the washing time is 8~10h.

4. The extraction process for high-purity Eucommia ulmoides gum as described in claim 1, characterized in that, (5) The Eucommia ulmoides fibers were dehydrated and spun dry using an industrial centrifuge.

5. The extraction process for high-purity Eucommia ulmoides gum as described in claim 1, characterized in that, The steps include the following: (1) Fresh Eucommia ulmoides leaves are used as raw materials, and are selected and air-separated for dust removal; (2) The fresh green leaves of Eucommia ulmoides that have been pretreated in (1) are rubbed using a rubbing and separating machine. First, the Eucommia ulmoides leaves are rubbed until they are deeply folded and curled into strips. Then, the leaf pulp is rubbed to break up the leaf pulp cells and separate the leaf pulp from the leaf vein gum until the Eucommia ulmoides gum filaments are tangled into filaments. The remaining leaf vein gum filament filament clumps account for 22-28% of the raw material mass. (3) The Eucommia ulmoides gum filaments obtained after kneading in (2) are subjected to stepwise enzymatic hydrolysis using biological enzymes. The hydrolysate is filtered out to obtain residual solid Eucommia ulmoides gum filaments. The biological enzymes are, in order: lipase, pectinase, protease, and cellulase. The weight of lipase and pectinase is 1.8-2.2% and the weight of protease and cellulase is 0.8-1.5% based on the weight of Eucommia ulmoides leaves. (4) The residual Eucommia ulmoides gum filaments obtained in (3) were washed with a natural soap powder aqueous solution. The water temperature during washing was 45~50℃. The mixture was stirred during washing at a speed of 30~40 rpm and the washing time was 8~10 h. (5) The Eucommia gum obtained in (4) is repeatedly shaken and washed with clean water, and then dehydrated and dried in an industrial centrifuge to obtain anhydrous Eucommia gum.

6. The extraction process for high-purity Eucommia ulmoides gum as described in claim 5, characterized in that, In (3), the specific steps of the stepwise enzymatic hydrolysis are as follows: S1 Lipase hydrolysis: First, add the first buffer solution to the Eucommia ulmoides filaments obtained after kneading in (2), then add lipase, and hydrolyze for 8-15 h at 30-45℃ and 26-30 rpm. Filter the hydrolysate to obtain the residual Eucommia ulmoides filaments after hydrolysis. S2 pectinase hydrolysis: Add buffer solution II to the residual Eucommia ulmoides gum filaments after S1 hydrolysis, then add pectinase, and hydrolyze for 8-15 h at 40-50℃ and 26-30 rpm. Filter the hydrolysate to obtain the hydrolyzed residual Eucommia ulmoides gum filaments. S3 protease hydrolysis: Add buffer solution III to the residual Eucommia ulmoides gum filaments after S2 hydrolysis, then add protease, and hydrolyze for 10-20 h at 30-50℃ and 26-30 rpm. Filter the hydrolysate to obtain the hydrolyzed residual Eucommia ulmoides gum filaments. S4 Cellulase hydrolysis: Add buffer solution IV to the residual Eucommia ulmoides gum filaments after S3 hydrolysis, then add cellulase, and hydrolyze for 10-20 h at 40-60℃ and 26-30 rpm. Filter the hydrolysate to obtain the hydrolyzed residual Eucommia ulmoides gum filaments.

7. The extraction process for high-purity Eucommia ulmoides gum as described in claim 6, characterized in that, The buffer solutions I through IV are all buffer solutions containing citric acid and trisodium citrate, and the pH of buffer solution I is 7.8 to 8.5; the pH of buffer solution II is 3.0 to 4.5; the pH of buffer solution III is 3.0 to 4.0; and the pH of buffer solution IV is 5.2 to 6.8.

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