Soluble chitin extracted from natural traditional Chinese medicine maggot and preparation method thereof

Abstract

The invention relates to soluble chitin extracted from natural traditional Chinese medicine maggot and a preparation method thereof.The soluble chitin is obtained by extracting chitin of maggot powder through an alkaline method and then conducting modification through a modifying agent, the modifying agent is selected from one or more of 1, 2-epoxypropane and ethylene oxide, and the modifying agent is selected from one or more of 1, 2-epoxypropane and ethylene oxide. The mass / mol ratio of the maggot powder to the modifier is 1g: (0.05-0.2 mol). Compared with the prior art, the chitin extraction rate is high, the chitin is modified to be water-soluble, and the use occasion of the chitin is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of soluble chitosan preparation, and relates to soluble chitosan extracted from a natural Chinese medicine, wormwood, and a preparation method thereof. Background Art

[0002] Chitin, also known as chitin, chitosan, and chitosan, is a natural high molecular weight polysaccharide, mainly distributed in the shells of crustaceans, insect shells, and the cell walls of some lower plants (such as fungi) in nature. Chitosan is the product of chitosan being treated with concentrated alkaline solution and then deacetylated. It is also known as chitosan and deacetylated chitosan, and its chemical name is (1,4)-2-amino-2-deoxy-β-D-glucan.

[0003] In 1991, medical nutrition and food research institutions in Japan, the United States, and Europe defined it as the sixth element of life after carbohydrates, proteins, fats, vitamins, and minerals. Therefore, the modification research of chitin, chitosan, and their derivatives will be a hot topic for researchers in the future. This shows that the various excellent properties of chitin and chitosan and their abundant resources will surely give them a wider application prospect.

[0004] In recent years, interest in chitin / chitosan from insects has grown steadily. Studies have shown that insects contain about 10-15% chitin, and the chitin content in the shells of some insects after molting is as high as 40%. Although the content of insect chitin is slightly lower than that of crustaceans, it has some unique advantages. First, insects are numerous on the earth, widely distributed, have high reproduction rates and are easy to cultivate. Insect-derived chitosan can effectively solve the seasonal changes and geographical limitations of shrimp and crab chitosan, which is particularly important for land-based countries. Secondly, the extraction of chitosan from insects can be done using mild conditions, rather than the harsh conditions required for crustacean extraction. In addition, studies have shown that insect chitosan has higher purity, less minerals, proteins, and heavy metal residues than shrimp and crab chitosan. Therefore, insects can be used as an unconventional but feasible source of chitosan.

[0005] Grain worms, also known as maggots, grain worms, and water daffodils, are distributed throughout the country and have high yields. Usually, a pair of male and female flies can reproduce 266.6 billion flies in a summer, and 15 tons can be obtained as raw materials for chitin. Grain worms are rich in nutrients, containing high levels of oil, protein, chitin and other substances, and have great prospects for development and utilization. At present, there are many reports on the extraction and preparation of chitin and chitosan from crustaceans such as shrimps and crab shells, silkworm pupae, crickets and other insects at home and abroad, but there are few reports on the extraction of chitin and chitosan from grain worm pupae. The chitosan content in grain worm pupae is higher than that in shrimp and crab shells, while the carbonate and heavy metal content is low, the pigment is less, and the quality is far better than that in shrimp and crab shells. Therefore, in the current situation where the chitosan market is in short supply, it is of great significance to develop grain worm chitosan resources. Chitosan is insoluble in water, acid, alkali and almost all organic solvents. Because the low water solubility greatly limits its application, chitosan needs to be further modified.

[0006] Patent CN105384850A discloses a method for preparing chitosan from maggots, which includes cleaning and removing impurities from maggots, drying and crushing, subcritical extraction and degreasing, focused ultrasonic cycle extraction and deproteinization, decalcification, and horizontal spiral centrifugation to obtain chitosan. However, the yield of chitosan obtained in this patent is low and the product quality is poor; at the same time, the experimental method has too high requirements on equipment and high energy consumption.

[0007] Patent CN118027247A discloses a method for extracting chitin from black soldier fly larvae, comprising the following steps: drying and grinding black soldier fly larvae, sieving to obtain insect powder; adding organic solvent to the insect powder, extracting at 55-65°C for 2-4h, and then drying at 100-110°C for 1-3h to obtain defatted powder; first irradiating the defatted powder with plasma, then adding urea solution, ultrasonic treatment once, then adding alkaline protease solution, ultrasonic treatment twice, centrifuging and drying the precipitate to obtain deproteinized powder; adding acid solution to the deproteinized powder, stirring for 1-3h, filtering, washing the filter residue with water until neutral, and drying to obtain crude chitin. However, the patent adopts enzymatic hydrolysis, which is relatively costly. Summary of the invention

[0008] The purpose of the present invention is to overcome at least one defect of the above-mentioned prior art and provide a soluble chitosan extracted from a natural Chinese medicine, the grain worm, and a preparation method thereof. The chitosan of the present invention has a high extraction rate, and the modification to water-soluble chitosan greatly improves the application occasions of chitosan.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] One of the technical solutions of the present invention is to provide a soluble chitosan extracted from a natural Chinese medicine grain worm. The soluble chitosan is obtained by extracting chitosan from grain worm powder by an alkali method and then modifying it with a modifier. The modifier is selected from one or more of 1,2-propylene oxide and ethylene oxide. The mass / molar ratio of the grain worm powder to the modifier is 1g:(0.05-0.2mol).

[0011] One of the technical solutions of the present invention is to provide a method for preparing soluble chitosan extracted from the natural Chinese medicine worm, the method comprising the following steps:

[0012] S1. Sieve the grain insect powder to obtain fine insect powder;

[0013] S2, adding alkaline solution to the fine insect powder, mixing and reacting evenly to obtain grain insect homogenate;

[0014] S3, repeatedly freezing and thawing the grain insect homogenate to obtain a coarse dispersion of chitosan;

[0015] S4, adding the modifier solution to the chitosan crude dispersion to react fully to obtain a chitosan modified solution;

[0016] S5, adding an acidic solution to the chitosan modified solution to adjust the pH;

[0017] S6. The chitosan modified liquid is diafiltration and freeze-dried to obtain soluble chitosan extracted from the natural Chinese medicine Osmanthus flavus.

[0018] Furthermore, in step S2, the first solute of the alkaline solution is selected from one or more strong bases of sodium hydroxide (NaOH) and potassium hydroxide (KOH), the second solute is urea, the solvent is water, and the mass / mole / volume ratio of the fine insect powder, the first solute, the second solute and the solvent is 1g:(0.01-0.08mol):(0.05-0.3mol):(30-45mL).

[0019] Furthermore, in step S4, the solvent of the modifier solution is water with a concentration of 20-40 mol / L, and the volume / molar ratio of the chitosan crude dispersion to the modifier is (30-45 mL): (0.05-0.2 mol).

[0020] Furthermore, the mesh size of the sieving in step S1 is 50 to 70 meshes.

[0021] Furthermore, in step S2, the temperature of the mixed reaction is 0-10° C., and the time is 20-40 min.

[0022] Furthermore, in step S3, the temperature of repeated freezing and thawing is -90 to -70°C, the single time is 12 to 48 hours, the interval time is 6 to 24 hours, and the number of times is 2 to 4 times.

[0023] Furthermore, in step S4, the reaction temperature is 0 to 10° C. and the reaction time is 12 to 48 hours.

[0024] Furthermore, in step S5, the acidic solution is a hydrochloric acid aqueous solution, the concentration of the acidic solution is 0.5-1.5 mol / L, and the pH is adjusted to 7-8.

[0025] Further, the molecular weight of the dialysis filtration in step S6 is 10000-20000 kDa, and the time is 48-120 h;

[0026] The freeze-drying temperature is -70 to -50°C and the time is 48 to 96 hours.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The chitosan extraction process of the present invention is simple, the equipment is conventional, and the insoluble chitosan is further modified to increase the water solubility, which greatly improves the use occasions of chitosan and meets the requirements of green and environmentally friendly production;

[0029] (2) The chitosan extraction rate of the present invention is higher than that of the conventional extraction method, and the chitosan is modified to be water-soluble, which greatly increases the utilization of chitosan, which can not only turn fly maggots into treasure, but also create higher economic benefits; and the ash content is low, the yield is high, and the decalcification process can be omitted, the method is simple, and the process is controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic flow chart of a method for preparing soluble chitosan extracted from the natural Chinese medicine worm in an embodiment of the present invention;

[0031] Figure 2 This is a diagram showing the appearance of soluble chitin extracted from the natural Chinese medicine Ophiopogon japonicus in Example 1 of the present invention;

[0032] Figure 3 This is a diagram showing the dissolution of soluble chitin extracted from the natural Chinese medicine Oxytricha quinata in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0034] Unless otherwise specified, the equipment used in the following examples are all conventional equipment in the art; the reagents used are all commercially available products or prepared by conventional methods in the art unless otherwise specified. Anything not described in detail in the following examples can be achieved by conventional experimental means in the art.

[0035] Embodiment 1:

[0036] A soluble chitin extracted from a natural Chinese medicine, wormwood, and a preparation method thereof, such as Figure 1 As shown, the specific steps are as follows:

[0037] S1. Pass the fresh grain insect powder through a 60-mesh sieve to obtain fine insect powder;

[0038] S2, add sodium hydroxide urea mixed solution to 1g of fine insect powder, sodium hydroxide (McLean, NaOH) 1.4g (0.035mol), urea (McLean) 7g (0.12mol), water 35mL in potassium hydroxide urea mixed solution, stir thoroughly at 4°C for 30min under ice bath condition until complete reaction, and obtain grain insect homogenate;

[0039] S3, placing the grain insect homogenate in a -80°C refrigerator, transferring the grain insect homogenate from the -80°C refrigerator to room temperature for 12 hours every 24 hours, repeating the freeze-thaw cycle 3 times to obtain a coarse dispersion of chitosan;

[0040] S4, add 2 mL of 2 g / mL (34 mol / L) 1,2-propylene oxide (McLean) aqueous solution dropwise to the chitosan crude dispersion under ice bath conditions, react at 4°C for 24 h to obtain a chitosan modified solution;

[0041] S5, adding 1 mol / L dilute hydrochloric acid aqueous solution (Sinopharm Group) to the chitin modified solution to adjust the pH to 7.6;

[0042] S6. Filter the chitosan modified liquid to remove the precipitate, take the supernatant, dialysis filter for 72 hours, the dialysis molecular weight is 14000 kDa, filter the supernatant, freeze-dry at -60°C for 72 hours until it becomes sponge-like, and obtain 0.1g of soluble chitosan extracted from the natural Chinese medicine Osmanthus flavus. The chitosan extraction rate is 10% and the maximum solubility is 3g / L.

[0043] Embodiment 2:

[0044] A soluble chitosan extracted from a natural Chinese medicine, Ophiopogon japonicus, and a preparation method thereof are substantially the same as those in Example 1, except that in step S2, 1.4 g (0.035 mol) of NaOH, 7 g (0.12 mol) of urea, and 35 mL of water in a sodium hydroxide-urea mixed solution are replaced by 2 g (0.036 mol) of potassium hydroxide (McLean, KOH), 7 g (0.12 mol) of urea, and 40 mL of water in a potassium hydroxide-urea mixed solution, 2 mL of a 2 g / mL (34 mol / L) 1,2-propylene oxide aqueous solution in step S4 is replaced by 4 mL of a 1.5 g / mL (34 mol / L) ethylene oxide (Sinopharm Group) aqueous solution, the pH of the solution is adjusted from 7.6 to 7.8 in step S5, and the dialysis filtration time is increased from 72 h to 96 h in step S6, thereby obtaining 0.08 g of soluble chitosan extracted from the natural Chinese medicine, with a chitosan extraction rate of 8% and a maximum solubility of 2 g / L.

[0045] like Figure 2 As shown, it can be seen that the soluble chitosan prepared after dialysis and freeze-drying in the embodiment is light yellowish white, spongy and has a light texture.

[0046] 3 mg of the soluble chitosan in Example 1 was added to 1 mL of water and completely dissolved. Figure 3 As shown, it can be seen that the soluble chitosan aqueous solution in the embodiment is transparent and light yellow.

[0047] Comparative Example:

[0048] Chitosan (Aladdin).

[0049] The chitosan in the comparative example is soluble in concentrated formic acid and methanesulfonic acid, but insoluble in water, organic solvents, weak acids and alkaline solutions. Compared with the standard chitosan in the comparative example, the solubility of the soluble chitosan in the embodiment is greatly improved in the same volume of water.

[0050] The preparation process and preparation results of the soluble chitosan in the examples are compared, see Table 1.

[0051] Table 1 Comparison of preparation process and preparation results of soluble chitosan in the examples

[0052] Example Modification reagents Alkaline reagents Yield Maximum solubility 1 1,2-Propylene oxide NaOH / Urea 10％ 3g / L 2 Ethylene oxide KOH / Urea 8％ 2g / L

[0053] As shown in Table 1, it can be concluded that in Example 1, 1,2-propylene oxide and sodium hydroxide are used as reaction system reagents, and the soluble chitosan prepared has a higher yield and higher solubility.

[0054] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A soluble chitin extracted from a natural Chinese medicine, Ophiopogon japonicus, characterized in that: The soluble chitosan is obtained by extracting chitosan from grain insect powder by an alkali method and then modifying it with a modifier, wherein the modifier is selected from one or more of 1,2-propylene oxide and ethylene oxide, and the mass / molar ratio of the grain insect powder to the modifier is 1g:(0.05-0.2mol).

2. A method for preparing soluble chitosan extracted from the natural Chinese medicine worm as claimed in claim 1, characterized in that: The method comprises the following steps: S1. Sieve the grain insect powder to obtain fine insect powder; S2, adding alkaline solution to the fine insect powder, mixing and reacting to obtain grain insect homogenate; S3, repeatedly freezing and thawing the grain insect homogenate to obtain a coarse dispersion of chitosan; S4, adding the modifier solution to the chitosan crude dispersion to react and obtain a chitosan modified solution; S5, adding an acidic solution to the chitosan modified solution to adjust the pH; S6. The chitosan modified liquid is diafiltration and freeze-dried to obtain soluble chitosan extracted from the natural Chinese medicine Osmanthus flavus.

3. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Ophiopogon japonicus, according to claim 2, characterized in that: In step S2, the first solute of the alkaline solution is selected from one or more strong bases of sodium hydroxide and potassium hydroxide, the second solute is urea, and the solvent is water. The mass / mole / volume ratio of the fine insect powder, the first solute, the second solute and the solvent is 1g:(0.01-0.08mol):(0.05-0.3mol):(30-45mL).

4. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Ophiopogon japonicus, according to claim 2, characterized in that: In step S4, the solvent of the modifier solution is water with a concentration of 20-40 mol / L, and the volume / molar ratio of the chitosan crude dispersion to the modifier is (30-45 mL): (0.05-0.2 mol).

5. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Ophiopogon japonicus, according to claim 2, characterized in that: The mesh size of the sieving in step S1 is 50 to 70 meshes.

6. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Oxytricha quinata, according to claim 2, characterized in that: The temperature of the mixed reaction in step S2 is 0-10° C. and the time is 20-40 min.

7. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Oxytricha quinata, according to claim 2, characterized in that: The temperature of repeated freezing and thawing in step S3 is -90 to -70°C, the single time is 12 to 48 hours, the interval time is 6 to 24 hours, and the number of times is 2 to 4 times.

8. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Oxytricha quinata, according to claim 2, characterized in that: The reaction temperature in step S4 is 0-10° C. and the reaction time is 12-48 hours.

9. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Oxytricha quinata, according to claim 2, characterized in that: In step S5, the acidic solution is a hydrochloric acid aqueous solution, the concentration of the acidic solution is 0.5-1.5 mol / L, and the pH is adjusted to 7-8.

10. The method for preparing soluble chitosan extracted from a natural Chinese medicine, Oxytricha quinata, according to claim 2, characterized in that: The molecular weight of the dialysis filtration in step S6 is 10000-20000 kDa, and the time is 48-120 h; The freeze-drying temperature is -70 to -50°C and the time is 48 to 96 hours.

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