Method for preparing chitosan from hericium erinaceus processing residues
Through multi-step processing of the residual residue of the cereal mushroom and ultrasonic assisted alkali solution method, chitosan with different deacetylation degrees was successfully prepared, which solved the problems of resource waste and environmental pollution, and achieved efficient and low-cost chitosan extraction.
Patent Information
- Application Number
- CN202510384352.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2025-06-06
AI Technical Summary
The existing technology is difficult to effectively utilize the surplus of erectus ceramide processing, resulting in waste of resources and environmental pollution. At the same time, the method of extraction of chitosan on commercial scale is time-consuming, low-efficiency, high-cost and unfriendly.
By removing polysaccharides, demineralized, protein-removing and decolorizing the residual powder of ceruleus, then sonicating in a high concentration of NaOH solution and undergoing an oil bath reaction, chitosan with different degrees of deacetylation was successfully prepared.
It realizes the efficient utilization of the residual residue of the cerule mushroom processing, and prepares high-purity and low-cost chitosan, which has a simple and easy-to-control process and high safety, making it suitable for promotion and application.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of food, and more specifically, relates to a method for preparing chitosan with different deacetylation degrees by utilizing Hericium erinaceus processing residues. Background Art
[0002] The rare mushroom Hericium erinaceus is a traditional medicinal and edible fungus that is deeply loved by consumers. Since Hericium erinaceus polysaccharides have multiple biological activities, the current application of Hericium erinaceus resources is mainly focused on the extraction of soluble Hericium erinaceus polysaccharides. However, Hericium erinaceus will produce a large amount of processing residues after polysaccharide extraction. There are currently few reports on its high-value utilization. The irrational disposal of agricultural product processing residues and by-products will cause great waste of resources and environmental pollution.
[0003] The main component of the Hericium erinaceus processing residue after polysaccharide extraction is chitin, which is of plant origin and does not contain allergens. It is the precursor of chitosan. Chitosan is the only natural macromolecular cationic polysaccharide. Its scientific name is β-(1-4)-2-amino-2-deoxy-β-D-glucan, which is mainly produced by deacetylation of chitin. The conversion process from chitin to chitosan is mainly the N-acetyl group (-NHCOCH 3 , -NHAC) is replaced by a hydrogen atom. Chitosan is one of the most abundant biomass resources in nature, second only to cellulose in reserves, and is widely distributed in the shells of crustaceans, the epidermis of insects, the skeletons of mollusks, and the cell walls of fungi. Currently, commercial chitosan mainly comes from marine crustaceans, whose source and growth environment are limited, and chitosan extracted from marine crustaceans is prone to allergenic risks. At present, the use of insect and fungal chitosan is relatively rare, and the acquisition of chitosan from Hericium erinaceus resources is slow.
[0004] The main methods for extracting chitosan are biological and chemical methods. The biological method mainly uses the metabolites produced by microorganisms to purify chitin, such as lactic acid and proteolytic enzymes from bacterial metabolism, which can directly demineralize and deproteinize it, but this technology is still in the laboratory stage and has not yet achieved maturity. The chemical method is the main method on a commercial scale, but it is time-consuming, inefficient, costly, and environmentally unfriendly. Summary of the invention
[0005] Based on this, the object of the present invention is to provide a method for preparing chitosan by utilizing the residues from processing Hericium erinaceus. The method is simple and efficient, and can prepare chitosan with different deacetylation degrees with a high yield.
[0006] The specific technical solutions for achieving the above-mentioned invention objectives include the following.
[0007] The first aspect of the present invention provides a method for preparing chitosan using Hericium erinaceus processing residues, comprising the following steps: sequentially performing polysaccharide removal, demineralization, deproteinization and decolorization treatments on Hericium erinaceus processing residue powder to obtain a precipitate, adding 40wt% to 60wt% NaOH solution to the precipitate, ultrasonically treating for 20min to 40min, and reacting in an oil bath at 85°C to 95°C for 4h to 6h.
[0008] The second aspect of the present invention provides chitosan prepared by the above preparation method.
[0009] In the present invention, the chitin obtained by sequentially removing polysaccharides, demineralizing, removing proteins and decolorizing the residue of Hericium erinaceus is dissolved in a high-concentration NaOH solution, and then ultrasonically treated for a certain period of time, and then combined with a high-temperature oil bath, Hericium erinaceus chitosan is successfully prepared, and chitosan with different deacetylation degrees can be prepared by controlling the concentration of the NaOH solution and the duration of the ultrasonic treatment. The Hericium erinaceus chitosan prepared by the present invention has a high yield (up to 25%) and is pure, and almost no other elements are contained therein.
[0010] The method for preparing chitosan by utilizing the residue from processing Hericium erinaceus of the present invention is simple and easy to control, not only treats the Hericium erinaceus processing waste, but also the obtained chitosan has no risk of allergies during use, has high safety, and is suitable for practical promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 The scanning electron microscope morphology images of chitin and chitosan prepared in Example 1 of the present invention and chitosan prepared in Examples 2 to 6 are shown.
[0012] Figure 2 The Fourier transform infrared spectra of the chitin and chitosan prepared in Example 1 of the present invention, the chitosan prepared in Examples 2 to 6, and the chitosan prepared in Comparative Examples 1 to 7 are shown.
[0013] Figure 3 These are optical photographs of chitin and chitosan prepared from the Hericium erinaceus processing residue HER in Example 1 of the present invention, and chitosan prepared in Examples 2 to 6. In the figure, HER, CT, CS-1, CS-2, CS-3, CS-4, CS-5, and CS-6 are represented from left to right.
[0014] Figure 4 These are optical photographs of chitosan prepared in Comparative Examples 1 to 7 of the present invention. In the figure, CK-1, CK-2, CK-3, CK-4, CK-5, CK-6, and CK-7 are represented from left to right.
[0015] Figure 5The X-ray photoelectron spectrum (A) and N1s spectrum (BG) of the chitin and chitosan prepared in Example 1 of the present invention, and the chitosan prepared in Examples 2 to 6. DETAILED DESCRIPTION
[0016] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.
[0017] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.
[0018] In some embodiments of the present invention, a method for preparing chitosan using Hericium erinaceus processing residue is disclosed, comprising the following steps: sequentially subjecting Hericium erinaceus processing residue powder to polysaccharide removal, demineralization, deproteinization and decolorization to obtain a precipitate, adding 40wt% to 60wt% NaOH solution to the precipitate, ultrasonically treating for 20min to 40min, and reacting in an oil bath at 85°C to 95°C for 4h to 6h.
[0019] In some embodiments, the concentration of the NaOH solution is 50 wt % to 60 wt %.
[0020] In some embodiments, the concentration of the NaOH solution is 58 wt % to 60 wt %.
[0021] In some embodiments, the ultrasonic treatment time is 30 min to 40 min.
[0022] In some embodiments, the ultrasonic treatment time is 35 min to 40 min.
[0023] In some embodiments, the temperature of the oil bath reaction is 88° C. to 92° C., and the time of the oil bath reaction is 4.5 h to 5.5 h.
[0024] In some embodiments, the frequency of the ultrasonic treatment is 30kHz to 50kHz, and the power of the ultrasonic treatment is 200W to 400W.
[0025] In some embodiments, the frequency of the ultrasonic treatment is 35kHz to 45kHz, and the power of the ultrasonic treatment is 250W to 350W.
[0026] In some embodiments, the frequency of the ultrasonic treatment is 38kHz to 42kHz, and the power of the ultrasonic treatment is 280W to 320W.
[0027] In some embodiments, the mass volume ratio of the precipitate to the NaOH solution is 1 g: 8 mL to 12 mL.
[0028] In some of the embodiments, after the oil bath reaction, a step of vacuum freeze-drying the precipitate is also included.
[0029] In some embodiments, the vacuum freeze-drying includes: pre-freezing at -20°C to -30°C for 10 hours to 14 hours, and then vacuum freeze-drying at -25°C to -35°C for 36 hours to 48 hours.
[0030] In some of the embodiments, the Hericium erinaceus processing residue powder is prepared by the following steps: the residue after polysaccharide is extracted from Hericium erinaceus is passed through a 80-100 mesh sieve.
[0031] In some embodiments, the polysaccharide removal comprises the following steps: dispersing the Hericium erinaceus processing residue powder in water and bathing it in water at 80° C. to 90° C. for 4 h to 6 h.
[0032] In some of the embodiments, the mass ratio of the Hericium erinaceus processing residue powder to water is 1:95-105.
[0033] In some of the embodiments, the demineralization includes the following steps: adding 0.8 mol / L to 1.2 mol / L hydrochloric acid solution to the precipitate after polysaccharide removal, stirring the reaction at room temperature for 10 h to 14 h, and the mass volume ratio of the precipitate to the hydrochloric acid solution is 1 g: 8 mL to 12 mL.
[0034] In some embodiments, the protein removal includes the following steps: washing the demineralized precipitate to neutrality, adding 3wt% to 5wt% NaOH solution, and reacting at 80°C to 90°C for 3h to 6h, and the mass volume ratio of the precipitate to the NaOH solution is 1g:8mL to 12mL.
[0035] In some of the embodiments, the precipitate is washed to neutrality using a 350-450 mesh filter cloth.
[0036] In some embodiments, the decolorization comprises the following steps: washing the precipitate after protein removal to neutrality, adding 0.8 mol / L to 1.2 mol / L NaClO at pH 3.5 to 4.5, 2 aqueous solution, react at 70℃~80℃ for 1.5h~2.5h, the precipitate and NaClO 2 The mass volume ratio of the aqueous solution is 1g:8mL~12mL.
[0037] In some of the embodiments, the precipitate is washed to neutrality using a 350-450 mesh filter cloth.
[0038] In some embodiments, a method for preparing chitosan using Hericium erinaceus processing residues comprises the following steps:
[0039] (1) Passing the Hericium erinaceus processing residue through an 80-100 mesh sieve to obtain Hericium erinaceus processing residue powder, dispersing the Hericium erinaceus processing residue powder in water at a mass ratio of 1:95-105, and immersing in a water bath at 80° C.-90° C. for 4 h-6 h;
[0040] (2) filtering the precipitate, adding 0.8 mol / L to 1.2 mol / L hydrochloric acid solution to the precipitate at a ratio of 1 g: 8 mL to 12 mL, and stirring at room temperature for 10 h to 14 h;
[0041] (3) filtering the precipitate, washing the precipitate to neutrality using a 350-450 mesh filter cloth, adding a 3 wt % to 5 wt % NaOH solution to the precipitate at a ratio of 1 g: 8 mL to 12 mL, and reacting at 80° C. to 90° C. for 3 h to 6 h;
[0042] (4) Filter the precipitate, wash the precipitate to neutrality using a 350-450 mesh filter cloth, and add 0.8 mol / L-1.2 mol / L NaClO at a pH of 3.5-4.5 to the precipitate at a ratio of 1 g: 8 mL-12 mL. 2 Aqueous solution, react at 70℃~80℃ for 1.5h~2.5h;
[0043] (5) filtering the precipitate, washing the precipitate with a 350-450 mesh filter cloth until it is neutral, adding a 40 wt % to 60 wt % NaOH solution to the precipitate at a ratio of 1 g: 8 mL to 12 mL, ultrasonically treating the precipitate for 20 min to 40 min, and reacting the precipitate in an oil bath at 85° C. to 95° C. for 4 h to 6 h;
[0044] (6) Filter the precipitate and freeze-dry it in vacuum to obtain the product.
[0045] In other embodiments of the present invention, chitosan prepared by the above preparation method is disclosed.
[0046] In the following examples of the present invention, the raw materials used, unless otherwise specified, are conventional commercially available products; the methods used, unless otherwise specified, are conventional methods in the art.
[0047] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.
[0048] Example 1 A method for preparing chitosan using Hericium erinaceus processing residue
[0049] This embodiment provides a method for preparing chitosan by using the residue from Hericium erinaceus processing and adopting an ultrasound-assisted alkali method, comprising the following steps:
[0050] 1. Removing polysaccharides: crush the Hericium erinaceus processing residue (HER, Hericium erinaceus obtained from the Hericium erinaceus cultivation site in Pingnan County, Fujian Province, the residue after extracting functional active polysaccharides) with a grinder, pass through a 100-mesh sieve to obtain fine powder of the Hericium erinaceus processing residue, weigh 100g of the Hericium erinaceus processing residue fine powder and disperse it in 1L of deionized water, place it in a constant temperature water bath at 85°C for 5h to remove the residual polysaccharides in the Hericium erinaceus processing residue, and after the water bath, centrifuge at 3000rpm to remove the supernatant;
[0051] 2. Demineralization: Add 1000 mL of 1 mol / L hydrochloric acid solution to the precipitate obtained in step 1, stir and react at room temperature for 12 hours to remove the minerals contained in the precipitate. After the reaction is completed, centrifuge at 3000 rpm to remove the supernatant;
[0052] 3. Protein removal: The precipitate obtained in step 2 was repeatedly washed with a 400-mesh filter cloth until the precipitate changed from acidic to neutral; then 1000 mL of a 4% NaOH solution was added to the precipitate, and the reaction was carried out at 85°C for 5 hours with continuous stirring to remove the protein in the precipitate. After the reaction was completed, the precipitate was centrifuged at 3000 rpm and the supernatant was removed;
[0053] 4. Decolorization: Wash the precipitate obtained in step 3 repeatedly with a 400-mesh filter cloth until the precipitate changes from alkaline to neutral; then add 1000 mL of 1 mol / L NaClO 2 Aqueous solution, adjusted NaClO 2 The aqueous solution is reacted at pH = 4 at 75°C for 2 hours to bleach and separate the pigments contained therein. After the reaction is completed, centrifuge at 3000 rpm to remove the supernatant; the obtained white precipitate is chitin (CT), the precursor of chitosan;
[0054] 5. Deacetylation: The precipitate obtained in step 4 is repeatedly washed with a 400-mesh filter cloth until the precipitate changes from acidic to neutral; then 10 mL of a 40% NaOH solution is added to 1 g of the precipitate, and the mixture is treated under ultrasonic conditions of 40 kHz and 300 W for 20 min, and then reacted in an oil bath at 90° C. for 5 h to perform a high-temperature concentrated alkali deacetylation reaction. After the reaction is completed, the mixture is cooled to room temperature; the mixture is centrifuged at 3000 rpm to remove the supernatant;
[0055] 6. Vacuum drying: The precipitate obtained in step 5 was repeatedly washed with a 400-mesh filter cloth until the precipitate changed from alkaline to neutral. The precipitate was spread on a culture dish, pre-frozen at -20°C for 12 hours, and then vacuum freeze-dried at -30°C for 48 hours to obtain chitosan, which was marked as CS-1 with a yield of 25%.
[0056] Example 2
[0057] Except that the ultrasonic treatment time in step 5 is 40 min, the other steps of this example are the same as those of example 1. The chitosan prepared in this example is marked as CS-2, and the yield is 22%.
[0058] Example 3
[0059] Except for using 50% by mass NaOH solution in step 5, the other steps of this embodiment are the same as those of embodiment 1. The chitosan prepared in this embodiment is marked as CS-3, and the yield is 23%.
[0060] Example 4
[0061] This example is the same as Example 1 except that in step 5, a 50% by mass NaOH solution is used for ultrasonic treatment for 40 minutes. The chitosan prepared in this example is labeled as CS-4, and the yield is 22%.
[0062] Example 5
[0063] Except for using 60% NaOH solution by mass in step 5, the other steps of this embodiment are the same as those of embodiment 1. The chitosan prepared in this embodiment is marked as CS-5, and the yield is 20%.
[0064] Example 6
[0065] This example is the same as Example 1 except that in step 5, a 60% by mass NaOH solution is used for ultrasonic treatment for 40 minutes. The chitosan prepared in this example is labeled as CS-6, and the yield is 20%.
[0066] Comparative Example 1
[0067] This comparative example is the same as Example 2 except that in step 5, after adding 10 mL of 40% NaOH solution to 1 g of precipitate, ultrasonic treatment is not performed and the reaction is directly carried out in an oil bath at 90° C. for 5 h. The product prepared in this comparative example is marked as CK-1.
[0068] Comparative Example 2
[0069] This comparative example is the same as Example 3 except that in step 5, 25 mL of 50% NaOH solution is added to 1 g of precipitate, and the mixture is treated with microwave (power of 700 W) for 30 min without oil bath reaction. The product prepared in this comparative example is marked as CK-2.
[0070] Comparative Example 3
[0071] This comparative example is the same as Example 2 except that the temperature of the oil bath reaction is 60° C. in step 5. The product prepared in this comparative example is marked as CK-3.
[0072] Comparative Example 4
[0073] This comparative example is the same as Example 6 except that in step 5, the ultrasonic treatment time is 15 min. The product prepared in this comparative example is marked as CK-4.
[0074] Comparative Example 5
[0075] This comparative example is the same as Example 6 except that in step 5, the ultrasonic treatment time is 45 min. The product prepared in this comparative example is marked as CK-5.
[0076] Comparative Example 6
[0077] This comparative example is the same as Example 6 except that in step 5, the mass fraction of the NaOH solution used is 30%. The product prepared in this comparative example is marked as CK-6.
[0078] Comparative Example 7
[0079] This comparative example is the same as Example 6 except that in step 5, the mass fraction of the NaOH solution used is 70%. The product prepared in this comparative example is marked as CK-7.
[0080] Performance Testing
[0081] 1. Scanning electron microscope SEM observation
[0082] The chitin CT prepared in Example 1 and the chitosan CS-1 to CS-6 prepared in Examples 1 to 6 were observed by scanning electron microscope (SEM). The SEM images are as follows: Figure 1 As shown. Figure 1 It can be seen that the surface morphology of chitin and chitosan prepared using the residual residue of the precious mushroom Hericium erinaceus is irregular and rough, and the product is stable and uniform.
[0083] 2. Fourier transform infrared spectrum
[0084] The Fourier transform infrared spectra of chitin CT prepared in Example 1, chitosan CS-1 to CS-6 prepared in Examples 1 to 6, and samples CK-1 to CK-7 prepared in Comparative Examples 1 to 7 are shown in FIG. Figure 2 As shown. Figure 2 It can be seen that at 1647cm -1 、1319cm -1 and 1255cm -1 Amide I, amide III, and amide IV groups were detected nearby. Compared with chitin CT, CS-1 to CS-6 and CK-1 to CK-7 were at 1564 cm -1 Amide II groups were also detected at the sites, which indicated that the chitosans CS-1 to CS-6 prepared in Examples 1 to 6 and the samples CK-1 to CK-7 prepared in Comparative Examples 1 to 7 were all chitosans.
[0085] By comparing the Fourier transform infrared spectra, it can be found that CS-2 has a -1 The peak of the amide II group at 1564 cm -1 The peak of the amide II group at is also significantly stronger than that of CK-2 (50% NaOH+microwave treatment).
[0086] 3. Optical images, sample colors and main performance indicators
[0087] The optical images of the raw material Hericium erinaceus processing residue HER of Example 1, the chitin prepared in Example 1, and the chitosan CS-1 to CS-6 prepared in Examples 1 to 6 are as follows: Figure 3 As shown, the optical images of chitosan CK-1 to CK-7 prepared in Comparative Examples 1 to 7 are as follows Figure 4 The sample colors and main performance indicators of each embodiment and comparative example are shown in Table 1.
[0088] Table 1
[0089]
[0090]
[0091] Depend on Figure 3 and Figure 4 It can be seen that the Hericium erinaceus processing residue (HER) after polysaccharide extraction can still retain its original color. Compared with the Hericium erinaceus processing residue (HER), after a series of extraction and preparation steps, the chitin (CT) and chitosan samples (CS-1 to CS-6) obtained all showed a pure white color, and the chitosan samples (CK-1 to CK-7) also showed a pure white color. By comparing and analyzing the L * value (brightness), a* Value (redness) and b * The values (yellowness) show that compared with the Hericium erinaceus processing residue (HER), the brightness of chitin CT and chitosan CS-1 to CS-6 is improved, and the redness and yellowness are significantly reduced. The brightness of chitosan CK-1 obtained without ultrasonic treatment and chitosan CK-2 obtained by concentrated alkali + microwave treatment is lower than that of other CK samples. These results are consistent with Figure 3 and Figure 4 The optical photographs shown are highly consistent.
[0092] The deacetylation degree (DD) and relative molecular weight of chitosan were determined by acid-base titration and viscosity method. The results showed that chitosan samples with different deacetylation degrees were successfully prepared by ultrasound-assisted alkali solution method. The deacetylation degrees of chitosan prepared in Examples 1 to 6 were 52.53±1.23%, 57.55±1.77%, 67.58±2.30%, 78.23±1.74%, 85.66±0.95% and 92.18±2.11%, respectively. With the increase of NaOH concentration and the extension of ultrasonic time, the deacetylation degree of the prepared chitosan sample was higher and the molecular weight was lower.
[0093] Chitosan CK-1 of Comparative Example 1 was prepared without ultrasonic treatment, and its deacetylation degree was 50.31±1.54%, which was significantly lower than the deacetylation degree (57.55±1.77%) of CS-2 of Example 2. This indicates that ultrasonic treatment after concentrated alkali treatment improves deacetylation efficiency.
[0094] The chitosan CK-2 of Comparative Example 2 was prepared by 50% NaOH solution + microwave treatment, and its deacetylation degree was 55.83±1.32%, which was significantly lower than that of CS-3 (67.58±2.30%) prepared by 50% NaOH solution + ultrasonic treatment in Example 3. It was proved that the chitosan prepared by concentrated alkali + ultrasonic treatment had better performance than the chitosan prepared by concentrated alkali + microwave treatment.
[0095] Chitosan CK-3 of Comparative Example 3 was prepared by concentrated alkali + ultrasonic treatment and then oil bath at 60°C, and its deacetylation degree was 50.64±1.53%, which was also significantly lower than that of CS-2 of Example 2. This indicates that concentrated alkali + ultrasonic treatment followed by high-temperature oil bath can better promote the deacetylation of chitin.
[0096] Chitosan CK-4 and chitosan CK-5 of comparative examples 4 and 5 were prepared by concentrated alkali treatment and then ultrasonic treatment for 15 min and 45 min, respectively. Comparison between CS-5 and CK-4 shows that the deacetylation degree of the chitosan prepared therefrom significantly decreases when the ultrasonic time is reduced to 15 min, from 85.66% to 51.81%. Comparison between CS-6 and CK-5 shows that the deacetylation degree of the chitosan prepared therefrom does not continue to increase when the ultrasonic time is extended to 45 min, but instead decreases to 77.56%.
[0097] Chitosan CK-6 and chitosan CK-7 of Comparative Examples 6 and 7 were prepared by treating with 30% and 70% NaOH, respectively, and then ultrasonically treating for 40 minutes. Comparison between CS-2 and CK-6 shows that, under the same ultrasonic time, the NaOH concentration decreased, and the deacetylation degree of the chitosan prepared therefrom decreased significantly, and the deacetylation degree was only 50.99%. Comparison between CS-6 and CK-7 shows that, under the same ultrasonic time, the NaOH concentration increased to 70%, and the deacetylation degree of the chitosan prepared therefrom did not continue to increase, but decreased to 77.45%, and its deacetylation degree was even lower than that of using 50% NaOH.
[0098] 4. Full spectrum of X-ray photoelectron spectrum
[0099] The X-ray photoelectron spectra of chitin prepared in Example 1 and chitosan CS-1 to CS-6 prepared in Examples 1 to 6 are as follows: Figure 5 As shown in A, Figure 5 As shown in A, chitin and chitosan samples with different deacetylation degrees all showed characteristic absorption peaks of three elements, O1s, N1s and C1s, at 529.4 eV, 399.1 eV and 282.8 eV, which indicates that the chitosan molecules prepared by the method of the present invention are pure, with almost no other elements, and the peak intensity of N1s at 399.1 eV in chitosan shows an increasing trend with the increase of deacetylation degree.
[0100] Gaussian fitting was performed on the regions where the N1s characteristic peaks were located. The N1s spectra of chitosan CS-1 to chitosan CS-6 were as follows: Figure 5 From the results, we can find that the N1s spectra of chitosan are divided into two sub-peaks, the red area and the green area correspond to C-NH 2 Bond and C-NHCOCH 3 The peak area comparisons of the two sub-peaks are 5:5, 5.5:4.5, 6:4, 7:3, 8:2, 9:1 (CN * :N * -COCH 3This result is consistent with the deacetylation degree of chitosan prepared in Examples 1 to 6 shown in Table 1.
[0101] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0102] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. A method for preparing chitosan using residues from Hericium erinaceus processing, characterized in that: The following steps are involved: The residual powder of Hericium erinaceus is subjected to polysaccharide removal, demineralization, deproteinization and decolorization treatment in sequence to obtain a precipitate, and then a 40wt% to 60wt% NaOH solution is added to the precipitate, and after ultrasonic treatment for 20min to 40min, the precipitate is reacted in an oil bath at 85°C to 95°C for 4h to 6h.
2. The method for preparing chitosan using residues from Hericium erinaceus processing according to claim 1, characterized in that: The concentration of the NaOH solution is 50 wt% to 60 wt%, preferably 58 wt% to 60 wt%.
3. The method for preparing chitosan using residues from Hericium erinaceus processing according to claim 1, characterized in that: The temperature of the oil bath reaction is 88° C. to 92° C., and the time of the oil bath reaction is 4.5 h to 5.5 h.
4. The method for preparing chitosan using residues from Hericium erinaceus processing according to claim 1, characterized in that: The ultrasonic treatment time is 30 min to 40 min, preferably 35 min to 40 min.
5. The method for preparing chitosan using residues from Hericium erinaceus processing according to claim 1, characterized in that: The frequency of the ultrasonic treatment is 30kHz to 50kHz, and the power of the ultrasonic treatment is 200W to 400W; preferably, the frequency of the ultrasonic treatment is 35kHz to 45kHz, and the power of the ultrasonic treatment is 250W to 350W; more preferably, the frequency of the ultrasonic treatment is 38kHz to 42kHz, and the power of the ultrasonic treatment is 280W to 320W.
6. The method for preparing chitosan by using residues from Hericium erinaceus processing according to any one of claims 1 to 5, characterized in that: The mass volume ratio of the precipitate to the NaOH solution is 1 g: 8 mL to 12 mL.
7. The method for preparing chitosan by using residues from Hericium erinaceus processing according to any one of claims 1 to 5, characterized in that: After the oil bath reaction, the step of vacuum freeze drying the precipitate is also included; preferably, the vacuum freeze drying includes: pre-freezing at -20°C to -30°C for 10h to 14h, and then vacuum freeze drying at -25°C to -35°C for 36h to 48h.
8. The method for preparing chitosan by using residues from Hericium erinaceus processing according to any one of claims 1 to 5, characterized in that: The Hericium erinaceus processing residue powder is prepared by the following steps: the residue after extracting polysaccharides from Hericium erinaceus is passed through an 80-100 mesh sieve; And / or, the polysaccharide removal comprises the following steps: dispersing the Hericium erinaceus processing residue powder in water, and bathing in water at 80°C to 90°C for 4h to 6h; preferably, the mass ratio of the Hericium erinaceus processing residue powder to water is 1:95 to 105; And / or, the demineralization comprises the following steps: adding 0.8 mol / L to 1.2 mol / L hydrochloric acid solution to the precipitate after polysaccharide removal, stirring and reacting at room temperature for 10 h to 14 h, wherein the mass volume ratio of the precipitate to the hydrochloric acid solution is 1 g: 8 mL to 12 mL; And / or, the protein removal comprises the following steps: washing the demineralized precipitate to neutrality, adding 3wt% to 5wt% NaOH solution, reacting at 80°C to 90°C for 3h to 6h, the mass volume ratio of the precipitate to the NaOH solution is 1g:8mL to 12mL; preferably, washing the precipitate to neutrality using a 350-450 mesh filter cloth; And / or, the decolorization comprises the following steps: after washing the precipitate after protein removal to neutrality, adding a NaClO2 aqueous solution with a pH of 3.5 to 4.5 and a 0.8 mol / L to 1.2 mol / L solution, reacting at 70°C to 80°C for 1.5h to 2.5h, the mass volume ratio of the precipitate to the NaClO2 aqueous solution is 1g:8mL to 12mL; preferably, washing the precipitate to neutrality using a 350-mesh to 450-mesh filter cloth.
9. The method for preparing chitosan using Hericium erinaceus processing residue according to claim 1, characterized in that: The following steps are involved: (1) The Hericium erinaceus processing residue is passed through an 80-100 mesh sieve to obtain the Hericium erinaceus processing residue powder, and the Hericium erinaceus processing residue powder is dispersed in water at a mass ratio of 1:95-105, and the Hericium erinaceus processing residue powder is water bathed at 80° C. to 90° C. for 4 h to 6 h; (2) filtering the precipitate, adding 0.8 mol / L to 1.2 mol / L hydrochloric acid solution to the precipitate at a ratio of 1 g: 8 mL to 12 mL, and stirring at room temperature for 10 h to 14 h; (3) filtering the precipitate, washing the precipitate to neutrality using a 350-450 mesh filter cloth, adding a 3 wt % to 5 wt % NaOH solution to the precipitate at a ratio of 1 g: 8 mL to 12 mL, and reacting at 80° C. to 90° C. for 3 h to 6 h; (4) filtering the precipitate, washing the precipitate to neutrality using a 350-450 mesh filter cloth, adding a 0.8 mol / L-1.2 mol / L NaClO2 aqueous solution at a pH of 3.5-4.5 to the precipitate at a ratio of 1 g: 8 mL-12 mL, and reacting at 70° C.-80° C. for 1.5 h-2.5 h; (5) filtering the precipitate, washing the precipitate with a 350-450 mesh filter cloth until it is neutral, adding a 40 wt % to 60 wt % NaOH solution to the precipitate at a ratio of 1 g: 8 mL to 12 mL, ultrasonically treating the precipitate for 20 min to 40 min, and reacting the precipitate in an oil bath at 85° C. to 95° C. for 4 h to 6 h; (6) Filter the precipitate and freeze-dry it in vacuum to obtain the product.
10. Chitosan prepared by the method according to any one of claims 1 to 9.