A method for extracting chitin from shrimp shells and its application.

Abstract

This invention belongs to the field of chitin extraction, and discloses a method and application for extracting chitin from shrimp shells. The extraction method of this invention employs a plasma + ultrasound-assisted acid-base method to extract chitin from shrimp shells. This method boasts excellent extraction efficiency and product purity, and is a simple, safe, and efficient novel method for chitin extraction. Furthermore, the raw materials used in this method are safe and readily available, employing edible-grade weak acid and weak base solutions, eliminating the need for high-risk strong acids and bases. In the deproteinization process, the shrimp shell powder is pre-treated with plasma, and ultrasound-assisted deproteinization is utilized during the process, improving deproteinization efficiency without causing food safety issues or environmental pollution. This method has significant application prospects in industry, agriculture, fisheries, medicine, cosmetics, and food processing.

Description

Technical Field

[0001] This invention belongs to the field of chitin extraction, specifically relating to a method and application for extracting chitin from shrimp shells. Background Technology

[0002] Chitosan, also known as chitin, is an animal-derived cellulose with numerous biochemical properties. It is considered a biomass source for alternatives to petroleum-based biofuels and other functional compounds, and is a novel environmentally friendly biopolymer material for the 21st century. Chitosan has a wide range of applications, playing a significant role in industry, agriculture, fisheries, medicine, and cosmetics. Industrially, it can be used in textiles, clothing, dyes, paper, and water treatment. In agriculture, it can be used as an insecticide and plant antiviral agent. In fisheries, it can be used as fish feed. In cosmetics, it can be used as a beauty agent, hair protectant, and moisturizer. In medical supplies, it can be used in contact lenses, artificial skin, sutures, artificial dialysis membranes, and artificial blood vessels. Furthermore, chitosan has anti-cancer properties, inhibiting cancer cell metastasis, enhancing immunity, and protecting the liver and detoxifying the body. It can also be made into chitosan capsules, which can improve digestion and absorption, reduce fat and cholesterol intake, lower blood pressure, regulate blood lipids, promote ulcer healing, enhance immunity, lower blood pressure, improve insulin utilization, and benefit the prevention and treatment of diabetes. Chitosan has broad application prospects and high commercial value.

[0003] Chitin is abundant in nature, widely distributed in the skin of crustaceans, the exoskeletons of insects, and the cell walls of fungi. Currently, most chitin extraction methods utilize marine sources such as shrimp and crab shells. The extraction process primarily involves decalcification and deproteinization, with deproteinization being a crucial step in extracting chitin from shrimp shells. The most common method is the traditional acid-base extraction method, but this method still has many problems, such as excessively strong acids or alkalis and slow degradation rates. While the traditional acid-base method has high deproteinization efficiency, it uses strong alkalis, posing safety concerns in the production of chitin-based products. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for extracting chitin from shrimp shells and its application, specifically employing the following technical solution:

[0005] According to a first aspect of the present invention, a method for extracting chitin from shrimp shells is provided, comprising the following steps:

[0006] Shrimp shell powder is first subjected to plasma irradiation treatment; then it is added to citric acid solution for decalcification treatment, heated and stirred until no bubbles are generated, filtered, and washed until neutral to obtain decalcified shrimp shell powder; then the decalcified shrimp shell powder is added to urea solution and subjected to ultrasonic heating treatment at 50 ℃-60 ℃, filtered, and washed until neutral to obtain deproteinized shrimp shell powder; then it is subjected to bleaching treatment, decolorization treatment, filtration, washing until neutral, and drying to obtain chitin.

[0007] This invention employs a plasma-assisted ultrasonic treatment method to extract chitin from shrimp chitin, representing a novel optimization of the chitin extraction process. This invention is the first to propose using a "plasma + ultrasound" assisted acid-base method to extract chitin from shrimp chitin. Unlike traditional acid-base extraction methods, this method uses a weak acid and weak base, achieving excellent extraction efficiency. It is a simple, safe, and efficient novel method for chitin extraction. This extraction method is simple to operate, requires minimal equipment, and has low production costs. Furthermore, the raw materials used are safe and readily available, eliminating the need for high-risk strong acids and bases. During the deproteinization process, the shrimp shell powder is pre-treated with plasma, and ultrasound-assisted deproteinization further improves efficiency without causing food safety issues or environmental pollution. This method has significant application prospects in industry, agriculture, fisheries, medicine, cosmetics, and the food industry.

[0008] Preferably, the shrimp shell powder has a mesh size of 50-200 mesh. Different mesh sizes affect the deproteinization and decalcification processes during chitin extraction, thus indirectly impacting the quality of the chitin.

[0009] Preferably, the plasma irradiation treatment is performed using a chemical vapor deposition system with a working power of 120 W-160 W and a treatment time of 2 min-4 min. When the working power is too low or the time is too short, the plasma treatment effect is poor, affecting the purity of the subsequent chitin product; when the power is too high or the time is too long, the shrimp shell powder is prone to scorching and burning, resulting in chitin loss.

[0010] Preferably, the ultrasonic heating treatment conditions are: ultrasonic power of 300 W-600 W and time of 3 h-5 h. Ultrasonic heating is used to deproteinize shrimp shell powder; when the power is too low or the time is too short, the deproteinization effect is poor; while when the power is too high or the time is too long, the degree of deproteinization is not significantly improved.

[0011] Preferably, in the citric acid solution, the mass ratio of citric acid to water is 12 g:(100 mL-120 mL). Acidity in the solution is more suitable for decalcification and elution to neutrality. The prepared citric acid solution is placed in a water bath and stirred continuously at a reaction temperature of 50 ℃-60 ℃ until no more bubbles are generated, thus completing the decalcification treatment of the shrimp shell powder.

[0012] Preferably, the mass ratio of urea to water in the urea solution is 72 g:(140 mL-150 mL). Adding urea solution can deproteinize shrimp shell powder; when there is excessive urea, it is difficult to wash off; when there is too little urea, the degree of deproteinization is poor.

[0013] Preferably, the bleaching process involves adding deproteinized shrimp shell powder to acetone and bleaching for 10-15 minutes; the ratio of deproteinized shrimp shell powder to acetone is 1 g:(10 mL-12 mL). If the acetone ratio is too high, bleaching will be difficult.

[0014] Preferably, the decolorization process involves adding bleached shrimp shell powder to a hydrogen peroxide solution and stirring until the shrimp shell powder turns white; the mass ratio of hydrogen peroxide to water is 30 g:(100 mL-120 mL). When the hydrogen peroxide concentration is too low, bleaching is not effective; while when the hydrogen peroxide concentration is too high, elution is difficult.

[0015] According to a second aspect of the present invention, chitin extracted from shrimp shells by the above method is also provided. The chitin extracted by the present invention has a yield of over 40% and a purity of 30%-60%, and food-grade weak acid and weak alkali solutions are used in the extraction process, making it a safe and green chitin product.

[0016] According to a third aspect of the invention, the use of chitosan in the preparation of fabrics, paper, fish feed, cosmetics, pesticides and / or anticancer drugs is also provided.

[0017] The beneficial effects of this invention are as follows: The extraction method of this invention uses a "plasma + ultrasound" assisted acid-base method to extract chitin from shrimp chitin. This method has excellent extraction efficiency and product purity, and is a simple, safe, and efficient novel method for extracting chitin. This extraction method is simple to operate, requires minimal equipment, and has low production costs. Furthermore, the raw materials used in this method are safe and readily available, using edible-grade weak acid and weak base solutions, eliminating the need for high-risk strong acids and bases. In the deproteinization process, the shrimp shell powder is pre-treated with plasma, and ultrasound-assisted deproteinization is used during the process, improving deproteinization efficiency without causing food safety issues or environmental pollution. This method has great application prospects in industry, agriculture, fisheries, medicine, cosmetics, and food industries. Attached Figure Description

[0018] Figure 1The images show chitin products obtained after different sieve fractions were treated with a weak acid and weak alkali using a combination of plasma and ultrasound. Among them, (A) passed through a 20-mesh sieve, (B) passed through a 40-mesh sieve, (C) passed through a 50-mesh sieve, (D) passed through a 60-mesh sieve, (E) passed through an 80-mesh sieve, (F) passed through a 100-mesh sieve, (G) passed through a 120-mesh sieve, (H) passed through a 150-mesh sieve, (I) passed through a 180-mesh sieve, and (J) passed through a 200-mesh sieve.

[0019] Figure 2 The images show infrared spectra of chitin samples processed using different methods; where 1—untreated 50-mesh crayfish shell powder chitin; 2—plasma-treated 50-mesh crayfish shell powder chitin; 3—untreated 100-mesh crayfish shell powder chitin; 4—plasma-treated 100-mesh crayfish shell powder chitin; 5—untreated 200-mesh crayfish shell powder chitin; 6—plasma-treated 200-mesh crayfish shell powder chitin; 7—commercially available chitin.

[0020] Figure 3 The images shown are scanning electron microscope (SEM) images of chitin samples treated with different methods. (A) Untreated 50-mesh crayfish shell powder chitin, 10.00 k SE; (B) Plasma-treated 50-mesh crayfish shell powder chitin, 10.00 k SE; (C) Untreated 100-mesh crayfish shell powder chitin, 10.00 k SE; (D) Plasma-treated 100-mesh crayfish shell powder chitin, 10.00 k SE; (E) Untreated 200-mesh crayfish shell powder chitin, 10.00 k SE; (F) Plasma-treated 200-mesh crayfish shell powder chitin, 10.00 k SE; (G) Commercially available chitin, 10.00 k SE. Detailed Implementation

[0021] The following will provide a clear and complete description of the concept and technical effects of the present invention in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, solution and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0022] Example 1

[0023] A chitin extracted from shrimp shell powder, the extraction method of which includes the following steps:

[0024] Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 50-mesh sieve.

[0025] Step 2: Place the shrimp shell powder in an oven and dry it until the net weight remains unchanged. Then, perform plasma treatment through a three-zone chemical vapor deposition system. The system's operating power is set to 160 W, and the treatment lasts for 2 minutes.

[0026] Step 3: Place 12 g of shrimp shell powder in a beaker, and then prepare a 12% citric acid solution by dissolving 12 g of solid citric acid in 100 g of water. Then add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60 ℃ water bath until no bubbles are generated. After decalcification, wash the shrimp shell powder with distilled water until it is neutral.

[0027] Step 4: Dissolve 86.4 g of urea in 180 mL of water to prepare a concentrated urea solution, add it to the decalcified shrimp shell powder, heat it in an ultrasonic cleaner at 60 ℃ with a working power of 300 W, and react for 5 h. Then filter the shrimp shell powder with distilled water and wash it until it is neutral.

[0028] Step 5: Add acetone at a ratio of 1:10 (w / v) and mix with the shrimp shells for 10 min.

[0029] Step 6: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white.

[0030] Step 7: Wash and dry the shrimp shell powder. After washing away the sediment, place it in an 80℃ oven to dry, and obtain the following: Figure 1 The chitin shown in (C) has the following electron micrograph. Figure 3 As shown in (B).

[0031] Example 2

[0032] A chitin extracted from shrimp shell powder, the extraction method comprising the following steps (compared to Example 1 without plasma treatment):

[0033] Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 50-mesh sieve.

[0034] Step 2: Place 12 g of shrimp shell powder in a beaker, and then prepare a 12% citric acid solution by dissolving 12 g of solid citric acid in 100 g of water. Then add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60 ℃ water bath until no bubbles are generated. After decalcification, wash the shrimp shell powder with distilled water until it is neutral.

[0035] Step 3: Dissolve 86.4 g of urea in 180 mL of water to prepare a concentrated urea solution, add it to the decalcified shrimp shell powder, heat it in an ultrasonic cleaner at 60 ℃ with a working power of 300 W, and react for 5 h. Then filter the shrimp shell powder with distilled water and wash it until it is neutral.

[0036] Step 4: Add acetone at a ratio of 1:10 (w / v) and mix with the shrimp shells for 10 min.

[0037] Step 5: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white.

[0038] Step 6: Wash and dry the shrimp shell powder. After washing the precipitate, dry it in an 80 ℃ oven to obtain chitin. Its electron micrograph is shown below. Figure 3 As shown in (A).

[0039] Example 3

[0040] A chitin extracted from shrimp shell powder, the extraction method comprising the following steps (the sieve size is adjusted to 100 mesh compared to Example 1):

[0041] Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 100-mesh sieve.

[0042] Step 2: Place the shrimp shell powder in an oven and dry it until the net weight remains unchanged. Then, perform plasma treatment through a three-zone chemical vapor deposition system. The system's operating power is set to 160 W, and the treatment lasts for 2 minutes.

[0043] Step 3: Place 12 g of shrimp shell powder in a beaker, and then prepare a 12% citric acid solution by dissolving 12 g of solid citric acid in 100 g of water. Then add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60 ℃ water bath until no bubbles are generated. After decalcification, wash the shrimp shell powder with distilled water until it is neutral.

[0044] Step 4: Dissolve 86.4 g of urea in 180 mL of water to prepare a concentrated urea solution, add it to the decalcified shrimp shell powder, heat it in an ultrasonic cleaner at 60 ℃ with a working power of 300 W, and react for 5 h. Then filter the shrimp shell powder with distilled water and wash it until it is neutral.

[0045] Step 5: Add acetone at a ratio of 1:10 (w / v) and mix with the shrimp shells for 10 min.

[0046] Step 6: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white.

[0047] Step 7: Wash and dry the shrimp shell powder. After washing away the sediment, place it in an 80℃ oven to dry, and obtain the following: Figure 1 The chitin shown in (F) has the following electron micrograph. Figure 3 As shown in (D).

[0048] Example 4

[0049] A chitin extracted from shrimp shell powder, the extraction method comprising the following steps (compared to Example 3 without plasma treatment):

[0050] Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 100-mesh sieve.

[0051] Step 2: Place 12 g of shrimp shell powder in a beaker, and then prepare a 12% citric acid solution by dissolving 12 g of solid citric acid in 100 g of water. Then add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60 ℃ water bath until no bubbles are generated. After decalcification, wash the shrimp shell powder with distilled water until it is neutral.

[0052] Step 3: Dissolve 86.4 g of urea in 180 mL of water to prepare a concentrated urea solution, add it to the decalcified shrimp shell powder, heat it in an ultrasonic cleaner at 60 ℃ with a working power of 300 W, and react for 5 h. Then filter the shrimp shell powder with distilled water and wash it until it is neutral.

[0053] Step 4: Add acetone at a ratio of 1:10 (w / v) and mix with the shrimp shells for 10 min.

[0054] Step 5: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white.

[0055] Step 6: Wash and dry the shrimp shell powder. After washing the precipitate, dry it in an 80 ℃ oven to obtain chitin. Its electron micrograph is shown below. Figure 3 As shown in (C).

[0056] Example 5

[0057] A chitin extracted from shrimp shell powder, the extraction method comprising the following steps (the sieve size is adjusted to 200 mesh compared to Example 1):

[0058] Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 200-mesh sieve.

[0059] Step 2: Place the shrimp shell powder in an oven and dry it until the net weight remains unchanged. Then, perform plasma treatment through a three-zone chemical vapor deposition system. The system's operating power is set to 160 W, and the treatment lasts for 2 minutes.

[0060] Step 3: Take 12g of shrimp shell powder that has passed through a 100-mesh sieve and place it in a beaker. Then prepare a 12% citric acid solution by dissolving 12g of solid citric acid in 100g of water. Add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60℃ water bath until no more bubbles are generated. After decalcification, filter and wash the shrimp shell powder until it is neutral.

[0061] Step 4: Dissolve 86.4 g of solid urea in 180 mL of water to prepare a concentrated urea solution. Add the solution to the decalcified shrimp shell powder and heat in an ultrasonic cleaner at 60 °C (300 W) for 5 h. After reaction, filter and wash the shrimp shell powder until neutral (the protein concentration during the deproteinization process needs to be analyzed using an ELISA reader with the Coomassie brilliant blue method until the absorbance reaches 0.30).

[0062] Step 5: Add acetone at a ratio of 1:10 (w / v) and mix with the shrimp shells for 10 min.

[0063] Step 6: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white.

[0064] Step 7: Wash and dry the shrimp shell powder. After washing away the sediment, place it in an 80℃ oven to dry, and obtain the following: Figure 1 The chitin shown in (J) has the following electron micrograph. Figure 3 As shown in (F).

[0065] Example 6

[0066] A chitin extracted from shrimp shell powder, the extraction method comprising the following steps (compared to Example 5 without plasma treatment):

[0067] Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 200-mesh sieve.

[0068] Step 2: Take 12g of shrimp shell powder that has passed through a 100-mesh sieve and place it in a beaker. Then prepare a 12% citric acid solution by dissolving 12g of solid citric acid in 100g of water. Add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60℃ water bath until no more bubbles are generated. After decalcification, filter and wash the shrimp shell powder until it is neutral.

[0069] Step 3: Dissolve 86.4 g of solid urea in 180 mL of water to prepare a concentrated urea solution. Add the solution to the decalcified shrimp shell powder and heat in an ultrasonic cleaner at 60 °C (300 W) for 5 h. After reaction, filter and wash the shrimp shell powder until neutral (the protein concentration during the deproteinization process needs to be analyzed using an ELISA reader with the Coomassie Brilliant Blue method until the absorbance reaches 0.30).

[0070] Step 4: Add acetone at a ratio of 1:10 (w / v) and mix with the shrimp shells for 10 min.

[0071] Step 5: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white.

[0072] Step 6: Wash and dry the shrimp shell powder. After washing the precipitate, dry it in an 80 ℃ oven to obtain chitin. Its electron micrograph is shown below. Figure 3 As shown in (E).

[0073] The chitin obtained in Examples 1-6 was subjected to infrared detection, such as... Figure 2 As shown, the products from top to bottom correspond to Example 1, Example 4, Example 3, Example 5, Example 2, commercially available chitin, and Example 6. The results show that the refractive index of chitin obtained by the extraction method of the present invention is generally higher than that of chitin that has not undergone plasma treatment.

[0074] The results of chitin yield, purity and protein content of three types of shrimp shell powder extracted by plasma (Examples 1, 3 and 5) and untreated (Examples 2, 4 and 6) combined with ultrasound-assisted weak acid and weak base method are shown in Table 1.

[0075] Table 1

[0076] Example Total mass of crude shrimp shell powder / g Refined chitin solid mass / g Chitosan yield / % Chitosan purity / % Protein content / % 1 13.28±0.04 5.63±0.05 42.39±0.12b 30.19±0.16e 30.80±0.08b 2 12.00±0.08 6.20±0.04 51.67±0.10a 24.77±0.14f 49.93±0.13a 3 12.00±0.06 5.14±0.04 42.83±0.07b 35.40±0.08c 20.13±0.08d 4 12.00±0.05 3.87±0.05 32.25±0.08c 33.73±0.09d 27.28±0.14c 5 18.55±0.05 8.15±0.05 43.93±0.15b 55.39±0.14a 15.87±0.16f 6 12.00±0.04 2.94±0.06 24.50±0.13d 53.80±0.11b 18.60±0.14e

[0077] In summary, the chitin obtained by the extraction method of the present invention is superior to the chitin that has not undergone plasma treatment in terms of yield, purity, and deproteinization. Moreover, as the sieve mesh size increases, the yield of chitin decreases, but the purity can reach more than 55%, and the deproteinization rate can reach 84%.

[0078] Although the description of the invention has been quite detailed and particularly of several described embodiments, it is not intended to limit it to any of these details or embodiments or any particular embodiment, but should be considered as providing a broad possible interpretation of the claims by referring to the appended claims and taking into account the prior art, thereby effectively covering the intended scope of the invention. Furthermore, the invention has been described above with respect to embodiments foreseeable by the inventors in order to provide a useful description, and non-substantial modifications to the invention that have not yet been foreseen may still represent equivalent modifications.

Claims

1. A method for extracting chitin from shrimp shells, characterized in that, Includes the following steps: Step 1: Wash the shrimp shells and dry them in an oven until the net weight remains unchanged. Crush them into powder and pass them through a 200-mesh sieve. Step 2: Place the shrimp shell powder in an oven and dry it until the net weight remains unchanged. Then, perform plasma treatment through a three-zone chemical vapor deposition system. The system's operating power is set to 160 W, and the treatment lasts for 2 minutes. Step 3: Take 12g of shrimp shell powder that has passed through a 100-mesh sieve and place it in a beaker. Then prepare a 12% citric acid solution by dissolving 12g of solid citric acid in 100g of water. Add the citric acid solution to the beaker containing the shrimp shell powder. Stir the beaker continuously with a glass rod in a 60℃ water bath until no more bubbles are generated. After decalcification, filter and wash the shrimp shell powder until it is neutral. Step 4: Dissolve 86.4 g of solid urea in 180 mL of water to prepare a concentrated urea solution, add it to the decalcified shrimp shell powder, heat it in an ultrasonic cleaner at 60 ℃ with a working power of 300 W, and react for 5 h. After that, filter and wash the shrimp shell powder until it is neutral. The protein concentration needs to be analyzed by an enzyme-linked immunosorbent assay (ELISA) reader using the Coomassie brilliant blue method until the absorbance reaches 0.

30. Step 5: Add acetone at a ratio of 1g:10ml and mix with the shrimp shells for 10 minutes. Step 6: Add an equal amount of 30% hydrogen peroxide solution to the shrimp shell powder that has been decalcified and deproteinized, and heat in a magnetically stirred water bath at 90 °C for 1 h until the shrimp shell powder turns white. Step 7: Wash and dry the shrimp shell powder, wash the precipitate and dry it in an 80 ℃ oven to obtain chitin; The yield of chitin obtained using the described extraction method was 43.93 ± 0.15%. b The chitin purity was 55.39 ± 0.14%. a The protein content was 15.87 ± 0.16%. f %.

2. A chitin extracted from shrimp shells, characterized in that, It is prepared by the method described in claim 1.

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