Recovery process of polysaccharide in sweet tea residues and application of recovery process
By treating sweet tea residue with a eutectic solvent and a pulsed electric field to increase permeability and combining it with enzymatic hydrolysis, the problem of inefficient polysaccharide recovery from sweet tea residue was solved, resulting in a significant increase in polysaccharide yield.
Patent Information
- Application Number
- CN202511898410.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-03-03
AI Technical Summary
In sweet tea residue, cellulose, lignin and polysaccharides are tightly cross-linked through covalent and hydrogen bonds, forming a dense network structure. This results in low yield and long processing time for conventional water extraction, making it difficult to efficiently recover polysaccharides.
Sweet tea residue was treated with a low eutectic solvent and a pulsed electric field. The low eutectic solvent penetrated into the cell structure, swollen, and formed micropores. The pulsed electric field increased permeability, and the enzymatic hydrolysis broke weak bonds, thus improving the polysaccharide yield.
It significantly improved the polysaccharide yield, achieving efficient polysaccharide recovery with a yield of over 19%, which is superior to traditional methods.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of sweet tea residue recycling technology, specifically relating to a process for recovering polysaccharides from sweet tea residue and its application. Background Technology
[0002] Sweet tea residue is rich in fiber and polysaccharides (such as pectin and hemicellulose), and has high recycling value. However, as a remnant of plant cell walls, the cellulose and lignin in sweet tea residue are tightly cross-linked with the target polysaccharides (such as pectin and hemicellulose) through covalent and hydrogen bonds, forming a dense network structure that creates a natural "physical barrier." This results in low yield and long processing time for conventional water extraction methods. Summary of the Invention
[0003] To address the aforementioned problems, this invention provides a process for recovering polysaccharides from sweet tea residue and its application.
[0004] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a process for recovering polysaccharides from sweet tea residue, comprising the following steps: Sweet tea residue is pretreated, then enzymatically hydrolyzed, and then separated and purified. Pretreatment includes eutectic solvent synergistic pulsed electric field treatment; Eutectic solvents include choline chloride, sodium ethanolamine hydrochloride, and lactic acid.
[0005] In some possible implementations, the molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid is 1:(0.2~0.5):(1.5~1.8).
[0006] In some possible implementations, the water content of the eutectic solvent is 8% to 10%.
[0007] In some possible implementations, the preparation of the eutectic solvent includes the following steps: Choline chloride, sodium ethanolamine hydrochloride, and lactic acid were mixed and stirred at 80℃~90℃, and then water was added and stirring continued to obtain a eutectic solvent with a water content of 8%~10%.
[0008] In some possible implementations, the eutectic solvent-assisted pulsed electric field treatment includes the following steps: Apply a pulsed electric field to the mixture; The mixture includes the sweet tea residue and the eutectic solvent; The electric field strength of the pulsed electric field is 10kV / cm to 20kV / cm.
[0009] In some possible implementations, the solid-liquid ratio of the sweet tea residue to the eutectic solvent is 1 g: (15 ml ~ 20 ml).
[0010] In some possible implementations, the preparation of the mixture includes the following steps: The sweet tea residue and the eutectic solvent are mixed and stirred at 35°C to 40°C.
[0011] In some possible implementations, the pulse width of the pulsed electric field is 18 μs to 22 μs.
[0012] In some possible implementations, the pulse frequency of the pulsed electric field is 80 Hz to 120 Hz.
[0013] In some possible implementations, the duration of the applied pulsed electric field is 200 μs to 300 μs.
[0014] In some possible implementations, the enzymatic hydrolysis process includes the following steps: The pretreated wet sweet tea residue, buffer solution, and complex enzyme honeycomb blocks were mixed and then enzymatically hydrolyzed.
[0015] In some possible implementations, the solid-liquid ratio of the wet sweet tea residue, the complex enzyme in the complex enzyme cell block, and the buffer solution is 1g:(30U~35U):(18ml~22ml).
[0016] In some possible implementations, the pH of the buffer solution is 4 to 6.
[0017] In some possible implementations, the buffer solution is a citrate-disodium hydrogen phosphate buffer solution.
[0018] In some possible implementations, the complex enzyme cell block comprises a complex enzyme and a cell carrier; the complex enzyme is loaded on the cell carrier.
[0019] In some possible implementations, the enzymatic hydrolysis temperature is 40°C to 50°C.
[0020] In some possible implementations, the enzymatic hydrolysis time is 3 to 4 hours.
[0021] In some possible implementations, the stirring speed for the enzymatic hydrolysis is 100 rpm to 120 rpm.
[0022] In some possible implementations, the preparation of the composite enzyme cell block includes the following steps: The modified honeycomb carrier was coated with a slurry containing a composite enzyme. The compound enzyme mixture slurry includes a compound enzyme and a cross-linking agent.
[0023] In some possible implementations, the cellular carrier includes at least one of cellular carbon and cordierite cellular material.
[0024] In some possible implementations, the mass ratio of the complex enzyme to the cross-linking agent is 1:(0.03~0.07).
[0025] In some possible implementations, the crosslinking agent is glutaraldehyde.
[0026] In some possible implementations, the preparation of the modified cellular carrier includes the following steps: The cellular carrier is subjected to acidification followed by oxidation.
[0027] In some possible implementations, the complex enzyme includes pectinase, cellulase, and β-glucanase.
[0028] In some possible implementations, the preparation of the complex enzyme mixture slurry includes the following steps: After mixing pectinase, cellulase, β-glucanase and water, they are then mixed with the cross-linking agent.
[0029] In some possible implementations, the concentration of pectinase in the compound enzyme mixture is 15 U / g to 20 U / g.
[0030] In some possible implementations, the concentration of cellulase in the composite enzyme mixture slurry is 5 U / g to 8 U / g.
[0031] In some possible implementations, the concentration of β-glucanase in the complex enzyme mixture slurry is 10 U / g to 12 U / g.
[0032] In some possible implementations, the volume ratio of the composite enzyme mixture slurry to the modified cellular carrier is (100~200):1.
[0033] In some possible implementations, the coating process includes the following steps: The modified honeycomb carrier and the composite enzyme were mixed and impregnated in a slurry, and then dried to constant weight.
[0034] In some possible implementations, the separation and purification process includes the following steps: The clear liquid obtained after enzymatic hydrolysis was concentrated and then subjected to alcohol precipitation to obtain the product.
[0035] Secondly, the present invention provides an application of the above-mentioned polysaccharide recovery process from sweet tea residue in the field of polysaccharide recovery.
[0036] The present invention provides a process for recovering polysaccharides from sweet tea residue. The pretreatment includes treatment with a low eutectic solvent and a pulsed electric field, which allows the low eutectic solvent to penetrate into the cell structure of the sweet tea residue and cause it to swell. Applying a pulsed electric field can form reversible micropores in the cell membrane and cell wall of the sweet tea residue, greatly increasing permeability and allowing the low eutectic solvent to act more deeply, thereby inducing the breaking of weak bonds in the cell wall polysaccharides and thus increasing the polysaccharide yield (above 19%). Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.
[0038] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.
[0039] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.
[0040] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.
[0041] This invention provides a process for recovering polysaccharides from sweet tea residue, comprising the following steps: S10. Sweet tea residue is pretreated, then enzymatically hydrolyzed, and then separated and purified. Pretreatment includes eutectic solvent synergistic pulsed electric field treatment; Eutectic solvents include choline chloride, sodium ethanolamine hydrochloride, and lactic acid.
[0042] The polysaccharide recovery process from sweet tea residue provided in this invention includes a pretreatment process involving a eutectic solvent and a pulsed electric field. This allows the eutectic solvent to penetrate the cell structure of the sweet tea residue, causing it to swell. Applying a pulsed electric field can form reversible micropores in the cell membrane and cell wall of the sweet tea residue, greatly increasing permeability and allowing the eutectic solvent to act more deeply. This, in turn, induces the breakage of weak bonds in the cell wall polysaccharides, thereby increasing the polysaccharide yield.
[0043] In some embodiments, the preparation of sweet tea residue in step S10 above includes the following steps: S101. Dry the wet sweet tea residue until the moisture content is ≤8%, then crush and sieve it.
[0044] In some embodiments, in step S101 above, the drying temperature is 80°C to 90°C.
[0045] In some embodiments, in step S101 above, the sieve mesh size is 40 mesh.
[0046] In some embodiments, in step S10 above, the molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid in the eutectic solvent is 1:(0.2~0.5):(1.5~1.8).
[0047] In some embodiments, the CAS number for choline chloride is 67-48-1.
[0048] In some embodiments, the CAS number of lactic acid is 50-21-5.
[0049] In some embodiments, in step S10 above, the water content of the eutectic solvent is 8% to 10%.
[0050] In some embodiments, the preparation of the eutectic solvent in step S10 above includes the following steps: S102. Choline chloride, sodium ethanolamine hydrochloride and lactic acid are mixed and stirred at 80℃~90℃, then water is added and stirring is continued to obtain a eutectic solvent with a water content of 8%~10%.
[0051] In some embodiments, in step S10 above, the eutectic solvent-assisted pulsed electric field treatment includes the following steps: S103. Apply a pulsed electric field to the mixture; The mixture includes sweet tea residue and a eutectic solvent; The electric field strength of the pulsed electric field is 10kV / cm to 20kV / cm.
[0052] In the above-mentioned treatment with eutectic solvent and pulsed electric field, the eutectic solvent can penetrate into the cell structure of sweet tea residue and cause it to swell; applying a pulsed electric field can form reversible micropores in the cell membrane and cell wall of sweet tea residue, greatly increasing permeability, allowing the eutectic solvent to act more deeply, thereby inducing the breakage of weak bonds in cell wall polysaccharides.
[0053] In some embodiments, in step S103 above, the solid-liquid ratio of sweet tea residue and eutectic solvent is 1g:(15ml~20ml).
[0054] In some embodiments, in step S103 above, the preparation of the mixture includes the following steps: S1031. Sweet tea residue and eutectic solvent are mixed and stirred at 35℃~40℃.
[0055] In some embodiments, in step S1031 above, the stirring speed is 30 rpm to 50 rpm.
[0056] In some embodiments, in step S1031 above, the stirring time is 30 min to 40 min.
[0057] In some embodiments, in step S103 above, the pulse width of the pulsed electric field is 18μs~22μs.
[0058] In some embodiments, in step S103 above, the pulse frequency of the pulsed electric field is 80 Hz to 120 Hz.
[0059] In some embodiments, in step S103 above, the duration of applying the pulsed electric field is 200 μs to 300 μs.
[0060] In some embodiments, the eutectic solvent-assisted pulsed electric field treatment in step S10 above further includes the following steps: S104. Obtain wet sweet tea residue after applying a pulsed electric field.
[0061] In some embodiments, in step S104 above, obtaining the wet sweet tea residue after applying a pulsed electric field includes the following steps: S1041. The mixture after applying a pulsed electric field is mixed with water and then centrifuged to obtain wet sweet tea residue.
[0062] In some embodiments, in step S1041 above, the volume ratio of the mixture after applying the pulsed electric field to water is 1:(1.2~1.5).
[0063] In some embodiments, in step S1041 above, the supernatant from centrifugation is dehydrated and concentrated using a nanofiltration membrane (molecular weight cutoff 200 Da) to obtain a eutectic solvent. In this case, the eutectic solvent recovered from the supernatant can be mixed again with sweet tea residue for the aforementioned pretreatment.
[0064] In some embodiments, in step S10 above, the enzymatic hydrolysis treatment includes the following steps: S105. The pretreated wet sweet tea residue, buffer solution, and complex enzyme honeycomb blocks were mixed and then enzymatically hydrolyzed.
[0065] In the above enzymatic hydrolysis process, the composite enzyme honeycomb block can specifically sever the linkage between the cell wall network of sweet tea residue and the target polysaccharide, allowing the polysaccharide to dissolve in large quantities in the form of intact macromolecules. After enzymatic hydrolysis, there is no need to inactivate the enzyme; the composite enzyme honeycomb block can be directly removed, which is simple and convenient.
[0066] In some embodiments, in step S105 above, the solid-liquid ratio of wet sweet tea residue, complex enzyme in complex enzyme honeycomb block and buffer is 1g:(30U~35U):(18ml~22ml).
[0067] In some embodiments, in step S105 above, the pH value of the buffer solution is 4 to 6.
[0068] In some embodiments, in step S105 above, the buffer solution is citrate-disodium hydrogen phosphate buffer.
[0069] In some embodiments, in step S105 above, the complex enzyme cell block comprises a complex enzyme and a cell carrier; the complex enzyme is loaded on the cell carrier.
[0070] In some embodiments, the cellular carrier includes at least one of cellular carbon and cordierite cellular material.
[0071] In some embodiments, the preparation of the composite enzyme cell block in step S105 above includes the following steps: S1051. Coating treatment of a slurry containing a modified honeycomb carrier and a composite enzyme; The compound enzyme mixture slurry includes a compound enzyme and a cross-linking agent.
[0072] In some embodiments, in step S1051 above, the mass ratio of the complex enzyme to the cross-linking agent is 1:(0.03~0.07).
[0073] In some embodiments, in step S1051 above, the crosslinking agent is glutaraldehyde.
[0074] In some embodiments, the preparation of the modified cellular carrier in step S1051 above includes the following steps: S10511. The cellular carrier is subjected to acidification followed by oxidation treatment.
[0075] In the preparation of the modified honeycomb carrier, the acidification treatment is used to dissolve and remove ash from the honeycomb carrier and open the channels of the honeycomb carrier to expose more of the original surface. At the same time, oxygen-containing functional groups are introduced on the surface of the honeycomb carrier to provide a cleaner and more active surface for subsequent loading of the complex enzyme slurry. The oxidation treatment oxidizes the surface of the honeycomb carrier and improves the binding strength of the complex enzyme.
[0076] In some embodiments, in step S10511 above, the acidification treatment includes the following steps: S105111. Mix the cellular carrier and acidification solution and acidify.
[0077] In some embodiments, in step S105111 above, the acidification solution is hydrochloric acid or nitric acid solution.
[0078] In some embodiments, the concentration of the acidification solution is 0.9 mol / L to 1.5 mol / L.
[0079] In some embodiments, the solid-liquid ratio of the cellular carrier to the acidification solution is 1 g: (10 ml to 15 ml).
[0080] In some embodiments, in step S105111 above, the acidification temperature is 60°C to 80°C.
[0081] In some embodiments, in step S105111 above, the acidification time is 2h to 4h.
[0082] In some embodiments, the acidification treatment in step S10511 above further includes the following steps: S105112. Wash the acidified honeycomb carrier with water until the pH value of the water is neutral, and then dry it to constant weight.
[0083] In the above acidification process, water washing removes excess acidification solution, and drying removes residual water, thus fully exposing the active sites of the cellular carrier.
[0084] In some embodiments, in step S105112 above, the drying temperature is 100°C to 110°C.
[0085] In some embodiments, in step S10511 above, the oxidation treatment includes the following steps: S105113. The honeycomb carrier obtained by acidification is mixed with an oxidation solution for oxidation.
[0086] In some embodiments, in step S105113 above, the solid-liquid ratio of the acidified honeycomb carrier to the oxidation solution is 1g:(10ml~20ml).
[0087] In some embodiments, in step S105113 above, the oxidizing liquid is a hydrogen peroxide solution.
[0088] In some embodiments, the mass fraction of hydrogen peroxide in the hydrogen peroxide solution is 10% to 30%.
[0089] In some embodiments, in step S105113 above, the oxidation temperature is 40°C to 60°C.
[0090] In some embodiments, the oxidation time in step S105113 is 6h to 12h.
[0091] In some embodiments, in step S10511 above, the oxidation treatment further includes the following steps: S105114. Remove the oxidized honeycomb carrier, wash it with water until no H2O2 residue remains, and then dry it to constant weight.
[0092] In some embodiments, in step S105114 above, the drying temperature is 100°C to 110°C.
[0093] In some embodiments, the complex enzyme includes pectinase, cellulase, and β-glucanase.
[0094] In some embodiments, the preparation of the composite enzyme mixture slurry in step S1051 above includes the following steps: S10512. Mix pectinase, cellulase, β-glucanase and water, then mix with a cross-linking agent.
[0095] In some embodiments, in step S1051 above, the concentration of pectinase in the compound enzyme mixed slurry is 15 U / g to 20 U / g.
[0096] In some embodiments, in step S1051 above, the concentration of cellulase in the composite enzyme mixture slurry is 5 U / g to 8 U / g.
[0097] In some embodiments, in step S1051 above, the concentration of β-glucanase in the complex enzyme mixture slurry is 10 U / g to 12 U / g.
[0098] In some embodiments, in step S1051 above, the volume ratio of the composite enzyme mixture slurry to the modified cellar carrier is (100~200):1.
[0099] In some embodiments, in step S1051 above, the coating process includes the following steps: S10512. Modified cell carrier and composite enzyme mixed slurry are mixed, impregnated, and then dried to constant weight.
[0100] In some embodiments, in step S10512 above, the immersion treatment time is 10 min to 15 min.
[0101] In some embodiments, in step S10512 above, the drying temperature is 35°C to 40°C.
[0102] In some embodiments, in step S105 above, the enzymatic hydrolysis temperature is 40°C to 50°C.
[0103] In some embodiments, in step S105 above, the enzymatic hydrolysis time is 3h~4h.
[0104] In some embodiments, in step S105 above, the stirring speed for enzymatic hydrolysis is 100 rpm to 120 rpm.
[0105] In some embodiments, the separation and purification process in step S10 above includes the following steps: S106. After obtaining the clear liquid after enzymatic hydrolysis, it is concentrated and then subjected to alcohol precipitation to obtain the product.
[0106] In some embodiments, obtaining the supernatant after enzymatic hydrolysis in step S106 above includes the following steps: S1061. Filter the mixture after enzymatic hydrolysis to obtain a clear liquid.
[0107] The clarified liquid obtained after enzymatic hydrolysis is filtered to remove residues such as complex enzyme honeycomb blocks and wet sweet tea dregs. Since the complex enzyme honeycomb blocks are blocky, they can be removed without an inactivation step.
[0108] In some embodiments, in step S106 above, the concentration process includes the following steps: S1062. The clarified liquid is concentrated under reduced pressure at 50℃~60℃ to 0.1 to 0.2 times its original volume to obtain a concentrated liquid.
[0109] In some embodiments, in step S106 above, the alcohol precipitation treatment includes the following steps: S1063. The concentrate and anhydrous ethanol were mixed and then precipitated.
[0110] In some embodiments, in step S1063 above, the volume of anhydrous ethanol is 3 to 5 times the volume of the concentrate.
[0111] In some embodiments, in step S1063 above, the temperature of anhydrous ethanol is 3°C to 4°C.
[0112] In some embodiments, in step S1063 above, the temperature of the net settling is 3°C to 4°C.
[0113] In some embodiments, in step S1063 above, the settling time is 12h to 24h.
[0114] In some embodiments, obtaining the product in step S106 above includes the following steps: S1064. Obtain the precipitate after alcohol precipitation, wash it and dry it to constant weight.
[0115] In some embodiments, in step S1064 above, obtaining the precipitate after alcohol precipitation includes the following steps: S10641. Centrifuge the mixture after alcohol precipitation to obtain the precipitate.
[0116] In some embodiments, in step S10641 above, the centrifugal separation speed is 7000 rpm to 8000 rpm.
[0117] In some embodiments, in step S10641 above, the centrifugation time is 20 min to 30 min.
[0118] In some embodiments, in step S1064 above, washing includes the following steps: S10642. Wash with anhydrous ethanol followed by acetone.
[0119] In some embodiments, in step S10642 above, the anhydrous ethanol washing is performed 2 to 3 times.
[0120] In some embodiments, in step S10642 above, the volume ratio of anhydrous ethanol to precipitate used in a single wash is (1~2):1.
[0121] In some embodiments, in step S10642 above, the acetone washing is performed 2 to 3 times.
[0122] In some embodiments, in step S10642 above, the volume ratio of acetone to precipitate used in a single wash is (1~2):1.
[0123] In some embodiments, in step S1064 above, the drying temperature is 40°C to 50°C.
[0124] The following description, in conjunction with specific embodiments, provides further details.
[0125] Example 1 Example 1 provides a process for recovering polysaccharides from sweet tea residue, the steps of which are as follows: E10. Pretreatment of sweet tea residue E101. Preparation of Eutectic Solvents Choline chloride, sodium ethanolamine hydrochloride, and lactic acid were mixed and stirred at 80°C, and then water was added and stirring continued to prepare a eutectic solvent with a water content of 8%; wherein the molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid was 1:0.3:1.7.
[0126] E102. Preparation of Sweet Tea Leaves The wet sweet tea residue was dried at 80℃ until the moisture content was ≤8%, then crushed and passed through a 40-mesh sieve.
[0127] E103. Eutectic Solvent Synergistic Pulsed Electric Field Treatment E1031. Sweet tea residue and eutectic solvent are mixed and stirred at 35°C to obtain a mixture; wherein, the stirring speed is 40 rpm and the stirring time is 30 min.
[0128] E1032. Apply a pulsed electric field to the mixture; wherein the solid-liquid ratio of sweet tea residue and eutectic solvent is 1g:18ml, the electric field strength of the pulsed electric field is 15kV / cm, the pulse frequency is 100Hz, and the duration is 200μs.
[0129] E1033. The mixture after applying a pulsed electric field is mixed with water and then centrifuged to obtain wet sweet tea residue; wherein the volume ratio of the mixture to water is 1:1.3.
[0130] E20. Enzymatic hydrolysis treatment E201. Preparation of composite enzyme cellar blocks E2011. Preparation of Modified Cellular Carriers (1) Acidification treatment 1) Mix the honeycomb carrier and the acidification solution and acidify; The honeycomb carrier is honeycomb carbon, the acidification solution is nitric acid solution with a concentration of 1.2 mol / L, the solid-liquid ratio of the honeycomb carrier and the acidification solution is 1 g: 13 ml, the acidification temperature is 70℃, and the time is 3 h.
[0131] 2) Wash the acidified honeycomb carrier with water until the pH value of the water is neutral, and then dry it at 100°C to constant weight.
[0132] (2) Oxidation treatment 1) The honeycomb carrier obtained by acidification is mixed with an oxidation solution for oxidation; The solid-liquid ratio of the acidified honeycomb carrier to the oxidation solution was 1g:15ml. The oxidation solution was a hydrogen peroxide solution with a mass fraction of 20%. The oxidation temperature was 50℃ and the time was 10h.
[0133] 2) Remove the oxidized honeycomb carrier, wash it with water until no H2O2 residue remains, and then dry it at 110℃ to constant weight to obtain the modified honeycomb carrier.
[0134] E2012. Preparation of Compound Enzyme Mixture Slurry A complex enzyme consisting of pectinase, cellulase, and β-glucanase is mixed with water and then mixed with glutaraldehyde. The mass ratio of the compound enzyme to glutaraldehyde is 1:0.05; in the compound enzyme mixed slurry, the concentration of pectinase is 18 U / g, the concentration of cellulase is 7 U / g, and the concentration of β-glucanase is 10 U / g.
[0135] E2013. Coating Treatment The modified honeycomb carrier and the composite enzyme mixed slurry were mixed, impregnated, and then dried to constant weight to obtain the composite enzyme honeycomb block; The volume ratio of the compound enzyme mixture slurry to the modified honeycomb carrier was 150:1; the impregnation time was 15 min; and the drying temperature was 35℃.
[0136] E202. Enzymatic hydrolysis The pretreated wet sweet tea residue, citrate-disodium hydrogen phosphate buffer (pH 5), and complex enzyme honeycomb blocks were mixed and enzymatically hydrolyzed. The solid-liquid ratio of the complex enzyme and buffer solution in the wet sweet tea residue and complex enzyme honeycomb block was 1g:33U:18ml; the enzymatic hydrolysis temperature was 45℃, the time was 3h, and the stirring speed was 100rpm.
[0137] E30. Separation and purification process E301. Obtain the supernatant after enzymatic hydrolysis. The filtered enzymatically hydrolyzed mixture yields a clear liquid.
[0138] E302. Concentration Process The clear liquid was concentrated under reduced pressure at 50°C to 0.1 times its original volume to obtain the concentrated liquid.
[0139] E303. Alcohol Precipitation Treatment The concentrate was mixed with anhydrous ethanol at 4°C and then allowed to settle at 4°C for 18 hours. The volume of aqueous ethanol is four times that of the concentrated liquid.
[0140] E304. Obtaining Products E3041. Obtaining Precipitate The mixture after alcohol precipitation was centrifuged to obtain the precipitate; the centrifugation speed was 8000 rpm and the time was 20 min.
[0141] E3042. Washing The precipitate was washed twice with anhydrous ethanol and then twice with acetone. In the anhydrous ethanol washing process, the volume ratio of anhydrous ethanol to precipitate used in a single wash is 1:1; in the acetone washing process, the volume ratio of acetone to precipitate used in a single wash is 1:1.
[0142] E3043. Drying The washed precipitate was dried at 40°C to constant weight to obtain the polysaccharide product.
[0143] Example 2 Example 2 provides a process for recovering polysaccharides from sweet tea residue. The steps are basically the same as in Example 1, except that: In the preparation of the eutectic solvent in step E101, the molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid is 1:0.2:1.5.
[0144] In step E1032, a pulsed electric field is applied to the mixture. The solid-liquid ratio of the sweet tea residue and the eutectic solvent is 1g:15ml. The electric field strength of the pulsed electric field is 10kV / cm, the pulse frequency is 80 Hz, and the duration is 200μs.
[0145] Example 3 Example 3 provides a process for recovering polysaccharides from sweet tea residue. The steps are basically the same as in Example 1, except that: In the preparation of the eutectic solvent in step E101, the molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid is 1:0.5:1.8.
[0146] In step E1032, a pulsed electric field is applied to the mixture. The solid-liquid ratio of the sweet tea residue and the eutectic solvent is 1g:20ml. The electric field strength of the pulsed electric field is 20kV / cm, the pulse frequency is 120Hz, and the duration is 300μs.
[0147] Example 4 Example 4 provides a process for recovering polysaccharides from sweet tea residue. The steps are basically the same as in Example 1, except that: In the enzymatic hydrolysis of step E202, the solid-liquid ratio of the wet sweet tea residue, the complex enzyme in the complex enzyme honeycomb block, and the buffer solution is 1g:30U:18ml.
[0148] Example 5 Example 5 provides a process for recovering polysaccharides from sweet tea residue. The steps are basically the same as in Example 1, except that: In the enzymatic hydrolysis of step E202, the solid-liquid ratio of the wet sweet tea residue, the complex enzyme in the complex enzyme honeycomb block, and the buffer solution is 1g:35U:22ml.
[0149] Comparative Example 1 Comparative Example 1 provides a process for recovering polysaccharides from sweet tea residue, the steps of which are as follows: D10. Preprocessing The wet sweet tea residue was dried at 80℃ until the moisture content was ≤8%, then crushed and passed through a 40-mesh sieve to obtain dried sweet tea residue.
[0150] D20. Water extraction D201. Mixing: Mix dried sweet tea residue and water for 50 minutes to obtain a mixture; wherein, the solid-liquid ratio of dried sweet tea residue and water is 1:15.
[0151] D202. Heating extraction: Heat the mixture to 90°C and reflux for 2 hours.
[0152] D203. Solid-liquid separation: Centrifuge the refluxed mixture to obtain an aqueous extract; wherein the centrifugation speed is 6000 rpm and the time is 15 min.
[0153] D30. Concentrate The aqueous extract was concentrated under vacuum at 70°C to 0.2 times its original volume to obtain a concentrated solution.
[0154] D40. Alcohol precipitation The concentrate was mixed with anhydrous ethanol at 4°C and then allowed to settle at 4°C for 24 hours. The volume of aqueous ethanol is four times that of the concentrated liquid.
[0155] D50. Obtaining Products D501. Obtaining the precipitate The mixture after alcohol precipitation was centrifuged to obtain the precipitate; the centrifugation speed was 8000 rpm and the time was 20 min.
[0156] D502. Washing The precipitate was washed twice with anhydrous ethanol and then twice with acetone. In the anhydrous ethanol washing process, the volume ratio of anhydrous ethanol to precipitate used in a single wash is 1:1; in the acetone washing process, the volume ratio of acetone to precipitate used in a single wash is 1:1.
[0157] D503. Drying The washed precipitate was dried at 40°C to constant weight to obtain the polysaccharide product.
[0158] Comparative Example 2 Comparative Example 2 provides a process for recovering polysaccharides from sweet tea residue. The steps are basically the same as in Example 1, except that: In step E10, the pretreatment steps for sweet tea residue are as follows: (1) Preparation of eutectic solvent Choline chloride, sodium ethanolamine hydrochloride, and lactic acid were mixed and stirred at 80°C, and then water was added and stirring continued to prepare a eutectic solvent with a water content of 8%; wherein the molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid was 1:0.3:1.7.
[0159] (2) Preparation of sweet tea residue The wet sweet tea residue was dried at 80℃ until the moisture content was ≤8%, then crushed and passed through a 40-mesh sieve.
[0160] (3) Eutectic solvent synergistic ultrasonic treatment 1) Sweet tea residue and eutectic solvent were mixed and stirred at 35°C to obtain a mixture; wherein the stirring speed was 40 rpm and the stirring time was 30 min.
[0161] 2) Ultrasonic treatment of the mixture; wherein the solid-liquid ratio of sweet tea residue and eutectic solvent is 1g:18ml, the ultrasonic power is 300W, the ultrasonic temperature is 60℃, and the ultrasonic time is 50min.
[0162] 3) The ultrasonically treated mixture was mixed with water and then centrifuged to obtain wet sweet tea residue; wherein the volume ratio of the mixture to water was 1:1.3.
[0163] To verify the advancement of the polysaccharide recovery process from sweet tea residue provided in the embodiments of the present invention, the polysaccharide yield of the polysaccharide recovery processes from sweet tea residue provided in the embodiments and comparative examples of the present invention was determined, and the results are shown in Table 1 below.
[0164]
[0165] From Table 1 above, at least the following conclusions can be drawn: (1) In the examples and Comparative Example 1, the polysaccharide yield of the examples is above 19%, while the polysaccharide yield of Comparative Example 1 obtained by the traditional water extraction and alcohol precipitation method is only 10.69%. The polysaccharide recovery process in sweet tea residue provided by the present invention can significantly improve the extraction efficiency of polysaccharides in sweet tea residue.
[0166] (2) In the examples and comparative example 2, the polysaccharide yield of comparative example 2 was only 11.68%. It can be seen that ultrasound cannot significantly improve the extraction efficiency of polysaccharides from sweet tea residue. However, the polysaccharide recovery process from sweet tea residue provided in the embodiments of the present invention uses a low eutectic solvent combined with a pulsed electric field treatment before enzymatic hydrolysis, so that the low eutectic solvent penetrates into the cell structure of the sweet tea residue and causes it to swell. Applying a pulsed electric field can form reversible micropores in the cell membrane and cell wall of the sweet tea residue, greatly increasing permeability, allowing the low eutectic solvent to act more deeply, thereby triggering the breakage of weak bonds in the cell wall polysaccharides, and thus improving the polysaccharide yield.
[0167] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.
Claims
1. A process for recovering polysaccharides from sweet tea residue, characterized in that, Includes the following steps: Sweet tea residue is pretreated, then enzymatically hydrolyzed, and then separated and purified. Pretreatment includes eutectic solvent synergistic pulsed electric field treatment; Eutectic solvents include choline chloride, sodium ethanolamine hydrochloride, and lactic acid.
2. The process for recovering polysaccharides from sweet tea residue according to claim 1, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The molar ratio of choline chloride, sodium ethanolamine hydrochloride, and lactic acid is 1:0.2~0.5:1.5~1.8; (2) The water content of the eutectic solvent is 8%~10%; (3) The preparation of the eutectic solvent includes the following steps: Choline chloride, sodium ethanolamine hydrochloride, and lactic acid were mixed and stirred at 80℃~90℃, and then water was added and stirring continued to obtain a eutectic solvent with a water content of 8%~10%.
3. The process for recovering polysaccharides from sweet tea residue according to claim 1 or 2, characterized in that, The eutectic solvent-assisted pulsed electric field treatment includes the following steps: Apply a pulsed electric field to the mixture; The mixture includes the sweet tea residue and the eutectic solvent; The electric field strength of the pulsed electric field is 10kV / cm to 20kV / cm.
4. The process for recovering polysaccharides from sweet tea residue according to claim 3, characterized in that, It satisfies at least one of the following characteristics (1) to (5): (1) The solid-liquid ratio of the sweet tea residue and the eutectic solvent is 1g:15ml~20ml; (2) The preparation of the mixture includes the following steps: The sweet tea residue and the eutectic solvent are mixed and stirred at 35°C to 40°C; (3) The pulse width of the pulsed electric field is 18μs~22μs; (4) The pulse frequency of the pulsed electric field is 80 Hz to 120 Hz; (5) The duration of applying the pulsed electric field is 200μs~300μs.
5. The process for recovering polysaccharides from sweet tea residue according to claim 4, characterized in that, The enzymatic hydrolysis process includes the following steps: The pretreated wet sweet tea residue, buffer solution, and complex enzyme honeycomb blocks were mixed and then enzymatically hydrolyzed.
6. The process for recovering polysaccharides from sweet tea residue according to claim 5, characterized in that, It satisfies at least one of the following characteristics (1) to (7): (1) The solid-liquid ratio of the wet sweet tea residue, the complex enzyme in the complex enzyme honeycomb block and the buffer solution is 1g:30U~35U:18ml~22ml; (2) The pH value of the buffer solution is 4~6; (3) The buffer solution is citrate-disodium hydrogen phosphate buffer; (4) The composite enzyme honeycomb block comprises a composite enzyme and a honeycomb carrier; the composite enzyme is loaded on the honeycomb carrier; (5) The enzymatic hydrolysis temperature is 40℃~50℃; (6) The enzymatic hydrolysis time is 3h~4h; (7) The stirring speed for the enzymatic hydrolysis is 100 rpm to 120 rpm.
7. The process for recovering polysaccharides from sweet tea residue according to claim 6, characterized in that, The preparation of the composite enzyme honeycomb block includes the following steps: The modified honeycomb carrier was coated with a slurry containing a composite enzyme. The compound enzyme mixture slurry includes a compound enzyme and a cross-linking agent.
8. The process for recovering polysaccharides from sweet tea residue according to claim 7, characterized in that, It satisfies at least one of the following characteristics (1) to (4): (1) The honeycomb carrier includes at least one of honeycomb carbon and cordierite honeycomb; (2) The mass ratio of the composite enzyme to the cross-linking agent is 1:0.03~0.07; (3) The crosslinking agent is glutaraldehyde; (4) The preparation of the modified cellular carrier includes the following steps: The cellular carrier is subjected to acidification followed by oxidation. (5) The complex enzyme includes pectinase, cellulase and β-glucanase; (6) The preparation of the composite enzyme mixture slurry includes the following steps: After mixing pectinase, cellulase, β-glucanase and water, they are then mixed with the cross-linking agent; (7) The concentration of pectinase in the compound enzyme mixture is 15 U / g to 20 U / g; (8) The concentration of cellulase in the composite enzyme mixture slurry is 5 U / g to 8 U / g; (9) The concentration of β-glucanase in the composite enzyme mixture slurry is 10 U / g to 12 U / g; (10) The volume ratio of the composite enzyme mixture slurry to the modified honeycomb carrier is 100~200:1; (11) The coating process includes the following steps: The modified honeycomb carrier and the composite enzyme were mixed and impregnated in a slurry, and then dried to constant weight.
9. The process for recovering polysaccharides from sweet tea residue according to any one of claims 1 to 8, characterized in that, The separation and purification process includes the following steps: The clear liquid obtained after enzymatic hydrolysis was concentrated and then subjected to alcohol precipitation to obtain the product.
10. The application of a polysaccharide recovery process from sweet tea residue as described in any one of claims 1 to 9 in the field of polysaccharide recovery.