Method for extracting chitin from mushroom residues by using ultrasonic-assisted deep-eutectic solvent

Abstract

The invention discloses a method for extracting chitin from shiitake mushroom residues by using an ultrasonic-assisted deep-eutectic solvent, which belongs to the technical field of polysaccharide extraction and comprises the following steps: preparing dried shiitake mushroom powder, preparing the deep-eutectic solvent and extracting the chitin. According to the method for extracting the chitin from the mushroom residues through the ultrasonic-assisted deep-eutectic solvent, the natural deep-eutectic solvent serves as the solvent, ultrasonic synergistic extraction is adopted, the chitin extraction rate and the product purity are greatly improved, the extraction efficiency is high, the method is easy to operate, the process is easy to control, and the method is environmentally friendly, low in production cost and suitable for industrial production. A new thought is provided for further utilization of mushroom processing waste resources.

Description

Technical Field

[0001] The invention belongs to the technical field of polysaccharide extraction, and in particular is a method for extracting chitin from mushroom residues with the assistance of an ultrasonic wave and a low eutectic solvent. Background Art

[0002] Shiitake mushrooms have a unique flavor and are rich in protein, amino acids, minerals, and a variety of bioactive ingredients such as polysaccharides and sterols. During the production process of shiitake mushrooms, a large amount of waste, namely shiitake mushroom residue, is generated. At present, there is a lack of effective utilization of shiitake mushroom residue, which not only wastes a lot of valuable resources, but also causes environmental pollution if improperly handled. Therefore, developing methods or ways to utilize shiitake mushroom residues to achieve "waste into treasure" is of great significance for the healthy development of the shiitake mushroom industry. Chitin, also known as chitosan, is a high molecular polymer composed of β-(1,4)-2-acetylamino-2-deoxy-D-glucose residues, with a molecular weight ranging from tens of thousands to millions. Chitin is one of the most abundant biomass resources in nature and is widely distributed in the shells of crustaceans, insect epidermis, and fungal cell walls. Shiitake mushrooms are one of the common sources of chitin. Therefore, developing a method for efficiently extracting chitin from shiitake mushroom residues can realize the development and utilization of shiitake mushroom waste resources and increase the added value of the shiitake mushroom industry.

[0003] At present, the extraction methods of chitin can be mainly divided into chemical methods and biological methods. Among them, the chemical method is a common method for preparing chitin on a commercial scale, but this method is costly, has low extraction efficiency, and is environmentally unfriendly. The biological extraction method mainly utilizes microorganisms or hydrolytic enzyme systems for extraction, which is greener and more environmentally friendly than the chemical method, but the technology is not yet mature and mainly remains in laboratory-scale research, making it difficult to achieve industrialization.

[0004] Deep eutectic solvent (DES) extraction is a green extraction method developed in recent years, which has the advantages of simple preparation, low cost, biodegradability, and no pollution. As a new type of green medium, DES is generally composed of hydrogen bond donors and hydrogen bonds through intermolecular hydrogen bonding to form a uniform and stable mixture. At present, it has gradually been used in the field of extraction of bioactive substances. Summary of the invention

[0005] The purpose of the present invention is to provide a method for extracting chitin from shiitake mushroom residues with an ultrasound-assisted deep eutectic solvent, which solves the problems of low extraction efficiency, high cost, and environmental unfriendliness in traditional extraction methods. In order to improve the extraction efficiency, the present invention uses ultrasound to accelerate mass transfer during the extraction process, assists DES extraction, improves the extraction efficiency, and realizes the development and utilization of shiitake mushroom waste resources.

[0006] Technical solution: A method for extracting chitin from mushroom residues using an ultrasonic-assisted deep eutectic solvent, comprising the following steps:

[0007] S1. Preparation of dried mushroom powder: drying, crushing and sieving the raw materials of mushroom residue to obtain dryness;

[0008] S2. Preparation of low eutectic solvent: uniformly mix the hydrogen bond acceptor and the hydrogen bond donor in a certain molar ratio, stir until a transparent and uniform solvent system is formed, cool to room temperature, add distilled water, mix evenly and set aside;

[0009] S3, chitin extraction: mixing the dried shiitake mushroom powder and the low eutectic solvent prepared in S2 in a certain proportion, and performing ultrasonic-assisted extraction. After the extraction, filtering, washing, drying and sieving are performed to obtain shiitake mushroom chitin.

[0010] Furthermore, the specific operation of S1 is: removing impurities from the mushroom residue raw material, drying in a 55°C oven, crushing with a multifunctional crusher after drying, sieving through a 100-mesh sieve, and putting the obtained mushroom dry powder into a sealed bag and storing it in a dryer. Drying in a 55°C oven, if the temperature is too high, it will easily change color and turn black, and if the temperature is too low, the drying time will be too long.

[0011] Furthermore, in S2, the stirring conditions are: magnetic stirring at 80°C to 85°C for 2h to 3h.

[0012] Furthermore, in S2, the hydrogen bond acceptor is choline chloride, and the hydrogen bond donor is one of acetic acid, lactic acid, glycerol, urea and thiourea; and the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:(1-2).

[0013] Furthermore, in S2, the mass of the added distilled water is 10% to 40% of the sum of the mass of the hydrogen bond acceptor and the hydrogen bond donor.

[0014] Further, in S3, the dried shiitake mushroom powder and the low eutectic solvent prepared in S2 are mixed in a certain proportion, and ultrasonic-assisted extraction is performed. After the extraction is completed, the suspension is filtered with a 400-mesh filter cloth, washed with distilled water for several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain shiitake mushroom chitin. The 400-mesh sieve is selected to minimize the solid residue in the filtrate; the 100-mesh sieve is used to sieve the solid powder to obtain a relatively uniform powder.

[0015] Furthermore, in S3, the solid-liquid ratio of shiitake mushroom dry powder to the low eutectic solvent prepared in S2 is 10 mL / g to 40 mL / g, the extraction time is 30 min to 120 min; the extraction temperature is 25° C. to 65° C., and the ultrasonic power is 120 W.

[0016] Beneficial effects:

[0017] 1) The preparation method of the low eutectic solvent of the present invention is simple, the extraction process is easy to control, the energy consumption is low, the cost is low, the extraction time is short, the extraction efficiency is high, and the extraction process is green and environmentally friendly.

[0018] 2) The present invention adopts ultrasound to assist the low eutectic reagent to extract chitin from shiitake mushroom residue, which is more conducive to increasing the mass transfer rate and improving the chitin extraction efficiency. The method of the present invention plays an important role in promoting the development and high-value utilization of shiitake mushroom waste resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 are the chitin extraction rates and chitin purity of different deep eutectic solvents, where A, B, C, D, and E represent five DES reagents, namely, choline chloride-acetic acid, choline chloride-lactic acid, choline chloride-glycerol, choline chloride-urea, and choline chloride-thiourea;

[0020] Figure 2 The effects of different water addition amounts (10%, 20%, 30%, 40%, w / w) on the chitin extraction rate and chitin purity of the deep eutectic solvent;

[0021] Figure 3 The effects of different extraction temperatures (25℃, 35℃, 45℃, 55℃) on the chitin extraction rate and chitin purity of the deep eutectic solvent;

[0022] Figure 4 The effects of different extraction liquid-to-solid ratios (10 mL / g, 20 mL / g, 30 mL / g, 40 mL / g) on ​​the chitin extraction rate and chitin purity of the deep eutectic solvent;

[0023] Figure 5 The effect of different extraction times (30min, 60min, 90min, 120min) on the chitin extraction rate and chitin purity of low eutectic solvent. DETAILED DESCRIPTION

[0024] The technical scheme of the present invention is described in detail below by way of examples, but the protection scope of the present invention is not limited to the examples. In the following examples, the reagents described are commercially available unless otherwise specified, and the following experimental methods and detection methods are conventional experimental methods and detection methods unless otherwise specified.

[0025] Example 1

[0026] This embodiment is a method for extracting chitin from mushroom residues with the assistance of a deep eutectic solvent using ultrasound, which is carried out in the following steps:

[0027] S1: Preparation of dried mushroom powder: remove impurities from the mushroom residue raw material, dry it in an oven at 55°C, crush it with a multifunctional crusher after drying, sieve it through a 100-mesh sieve, put it into a sealed bag, and store it in a desiccator.

[0028] S2: Preparation of low eutectic solvent: The low eutectic solvent was prepared by the heating stirring method. According to Table 1, the hydrogen bond acceptor (choline chloride) and the hydrogen bond donor (acetic acid, lactic acid, glycerol, urea, thiourea) were uniformly mixed in a certain molar ratio, and magnetically stirred at 80°C to 85°C for 2h to 3h until a transparent uniform solution system was formed. The mixture was cooled to room temperature, 20% (w / w) distilled water was added, and the mixture was mixed uniformly to obtain low eutectic solvents A, B, C, D, and E.

[0029] Table 1. Composition and ratio of different deep eutectic solvents

[0030]

[0031] S3: Chitin extraction: The low eutectic solvents A, B, C, D, and E prepared in S2 were mixed with dried shiitake mushroom powder at a liquid-to-solid ratio of 20 mL / g, and ultrasonic-assisted extraction was performed at 55°C for 60 min at 120 W. After the extraction, the suspension was filtered with a 400-mesh filter cloth, washed with distilled water several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain the chitin of each shiitake mushroom.

[0032] S4: Chitin purity and extraction rate analysis: Shiitake chitin was dissolved in 1 mol / L NaOH solution, hydrolyzed at 120℃ for 30 min, centrifuged at 10000 r / min for 10 min, and the supernatant was taken to determine its protein content, the purity of shiitake chitin was calculated, and the chitin extraction rate was calculated based on the extraction amount. The results are shown in Figure 1 .

[0033] Example 2

[0034] This embodiment is a method for extracting chitin from mushroom residues with the assistance of a deep eutectic solvent using ultrasound, which is carried out in the following steps:

[0035] S1: Same as Example 1.

[0036] S2: Preparation of low eutectic solvent: The low eutectic solvent was prepared by heating and stirring method. Choline chloride and acetic acid were uniformly mixed in a molar ratio of 1:2, and magnetically stirred at 80℃~85℃ for 2h~3h until a transparent and uniform system was formed. The mixture was cooled to room temperature, and 10%, 20%, 30%, and 40% (w / w) distilled water were added respectively and mixed uniformly to obtain each group of low eutectic solvents.

[0037] S3: Chitin extraction: The low eutectic solvents with different water contents prepared in S2 were mixed with dried shiitake mushroom powder at a liquid-to-solid ratio of 20 mL / g, and ultrasonic-assisted extraction was performed at 55°C for 60 min at 120 W. After the extraction, the suspension was filtered with a 400-mesh filter cloth, washed with distilled water several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain the chitin of each shiitake mushroom.

[0038] S4: Same as Example 1, the results are shown in Figure 2 .

[0039] Example 3

[0040] This embodiment is a method for extracting chitin from mushroom residues with the assistance of a deep eutectic solvent using ultrasound, which is carried out in the following steps:

[0041] S1: Same as Example 1.

[0042] S2: Preparation of low eutectic solvent: A low eutectic solvent was prepared by a heating stirring method. Choline chloride and acetic acid were uniformly mixed in a molar ratio of 1:2, and magnetically stirred at 80°C to 85°C for 2h to 3h until a transparent and uniform system was formed. The mixture was cooled to room temperature, and 20% (w / w) distilled water was added and mixed uniformly for later use.

[0043] S3: Chitin extraction: The low eutectic solvent prepared in S2 was mixed with dried shiitake mushroom powder at a liquid-to-solid ratio of 20 mL / g, and 120 W ultrasonic-assisted extraction was performed at 25°C, 35°C, 45°C, and 55°C for 60 min. After the extraction, the suspension was filtered with a 400-mesh filter cloth, washed with distilled water several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain the chitin of each shiitake mushroom.

[0044] S4: Same as Example 1, the results are shown in Figure 3 .

[0045] Example 4

[0046] This embodiment is a method for extracting chitin from mushroom residues with the assistance of a deep eutectic solvent using ultrasound, which is carried out in the following steps:

[0047] S1: Same as Example 1.

[0048] S2: Same as Example 1.

[0049] S3: Chitin extraction: The low eutectic solvent prepared in S2 was mixed with dried shiitake mushroom powder at a liquid-to-solid ratio of 10 mL / g, 20 mL / g, 30 mL / g, and 40 mL / g, respectively, and 120 W ultrasonic-assisted extraction was performed at 55°C for 60 min. After the extraction, the suspension was filtered with a 400-mesh filter cloth, washed with distilled water several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain the chitin of each shiitake mushroom.

[0050] S4: Same as Example 1, the results are shown in Figure 4 .

[0051] Example 5

[0052] This embodiment is a method for extracting chitin from mushroom residues with the assistance of a deep eutectic solvent using ultrasound, which is carried out in the following steps:

[0053] S1: Same as Example 1.

[0054] S2: Same as Example 1.

[0055] S3: Chitin extraction: The low eutectic solvent prepared in S2 was mixed with dried shiitake mushroom powder at a liquid-to-solid ratio of 20 mL / g, and 120 W ultrasonic-assisted extraction was performed at 55°C for 30 min, 60 min, 90 min, and 120 min, respectively. After the extraction, the suspension was filtered with a 400-mesh filter cloth, washed with distilled water several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain the chitin of each shiitake mushroom.

[0056] S4: Same as Example 1, the results are shown in Figure 5 .

[0057] According to the method provided by the present invention, the extraction effects of five DES reagents, namely, choline chloride-acetic acid, choline chloride-lactic acid, choline chloride-glycerol, choline chloride-urea and choline chloride-thiourea, on chitin from shiitake mushroom residues were investigated. In addition to the molar ratio in Example 1, the present invention also tested a variety of molar ratios. When choline chloride:acetic acid=1:1 and choline chloride:acetic acid=1:3, the extraction rate was higher than that when choline chloride:acetic acid=1:2, and it was determined that the extraction effect was best when the choline chloride-acetic acid ratio was 1:2.

[0058] According to the method provided by the present invention, the effects of four factors, namely, the amount of water added (10%, 20%, 30%, 40%, w / w), the extraction temperature (25°C, 35°C, 45°C, 55°C), the liquid-to-solid ratio (10mL / g, 20mL / g, 30mL / g, 40mL / g), and the extraction time (30min, 60min, 90min, 120min), on the extraction of chitin from shiitake mushroom residues by choline chloride-acetic acid (1:2) were investigated. The experimental results showed that under the conditions of 20% of water added, 55°C of extraction temperature, 30mL / g of liquid-to-solid ratio, and 90min of extraction time, the extraction rate and purity of chitin from shiitake mushroom residues were both high.

[0059] In summary, the method for extracting chitin from shiitake mushroom residues using an ultrasound-assisted low eutectic solvent provided by the present invention avoids the use of concentrated acid, strong alkali and other extraction solvents, has the advantages of simple preparation, controllable extraction process, low cost, high extraction efficiency, high product purity, low pollution and green environmental protection, and can be used for the development of shiitake mushroom waste resources.

[0060] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for extracting chitin from mushroom residues using an ultrasound-assisted deep eutectic solvent. It is characterized in that The steps include: S1. Preparation of dried mushroom powder: drying, crushing and sieving the raw materials of mushroom residue to obtain dryness; S2. Preparation of low eutectic solvent: uniformly mix the hydrogen bond acceptor and the hydrogen bond donor in a certain molar ratio, stir until a transparent and uniform solvent system is formed, cool to room temperature, add distilled water, mix evenly and set aside; S3, chitin extraction: mixing the dried shiitake mushroom powder and the low eutectic solvent prepared in S2 in a certain proportion, and performing ultrasonic-assisted extraction. After the extraction, filtering, washing, drying and sieving are performed to obtain shiitake mushroom chitin.

2. The method according to claim 1, It is characterized in that The specific operation of S1 is: Impurities in the mushroom residue raw material are removed, and the mushroom residue is dried in an oven at 55°C. After drying, it is crushed by a multifunctional crusher and sieved through a 100-mesh sieve. The obtained mushroom dry powder is put into a sealed bag and stored in a desiccator.

3. The method according to claim 1, It is characterized in that In S2, the stirring conditions are: magnetic stirring at 80°C to 85°C for 2h to 3h.

4. The method according to claim 1, It is characterized in that In S2: the hydrogen bond acceptor is choline chloride, the hydrogen bond donor is one of acetic acid, lactic acid, glycerol, urea and thiourea; the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:(1-2).

5. The method according to claim 1, It is characterized in that In S2, the mass of the added distilled water is 10% to 40% of the sum of the mass of the hydrogen bond acceptor and the mass of the hydrogen bond donor.

6. The method according to claim 1, It is characterized in that In S3, the dried shiitake mushroom powder and the low eutectic solvent prepared in S2 are mixed in a certain proportion, and ultrasonic-assisted extraction is performed. After the extraction, the suspension is filtered with a 400-mesh filter cloth, washed with distilled water for several times, freeze-dried, and passed through a 100-mesh sieve after drying to obtain shiitake mushroom chitin.

7. The method according to claim 1, It is characterized in that In S3, the solid-liquid ratio of shiitake mushroom dry powder to the low eutectic solvent prepared in S2 is 10mL / g to 40mL / g, the extraction time is 30min to 120min; the extraction temperature is 25℃ to 65℃, and the ultrasonic power is 120W.

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