Fish skin albumen glue and preparation method thereof

Abstract

The invention discloses fish skin albumen glue and a preparation method thereof, and belongs to the technical field of food processing. The method comprises the following steps: by taking fish skin as a raw material, carrying out extrusion treatment on the fish skin; sequentially carrying out ultrasonic preliminary degreasing treatment and NaHCO3 solution two-step degreasing treatment on the extruded fish skin; performing quick-freezing and unfreezing treatment on the fish skin subjected to the two-step degreasing treatment; and performing gelatin extraction treatment on the quick-frozen and unfrozen fish skin to obtain the fish skin albumen glue. The preparation method has the advantages of simple preparation process, no pollution in the treatment process, greenness and environmental protection, and the prepared fish skin albumen glue is transparent, free of impurities and relatively good in gel property.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to fish skin protein glue and a preparation method thereof. Background Art

[0002] Gelatin, whose main component is a high-molecular-weight polypeptide polymer, contains 20 essential amino acids for the human body and is the product of the condensation of multiple amino acids in a certain proportion. The main sources of gelatin are currently mammals such as pigs and cattle. However, due to various factors, the use of mammalian protein gelatin has been restricted. Therefore, people have begun to focus on developing protein gelatin from other sources to replace mammalian protein gelatin. The main alternative source is fish protein gelatin.

[0003] my country is a major freshwater fish farming country, with annual output ranking first in the world. The freshwater fish farming industry is developing rapidly, and the output is increasing year by year. The processing of freshwater aquatic products is still at a relatively low level, with an utilization rate of only 30% to 50%, resulting in a large number of by-products such as fish scales, fish bones, and fish skin, resulting in a large amount of waste of high-quality resources. Among them, fish skin is rich in collagen and is often used as a raw material for extracting fish protein glue. However, due to the high fat content of fish skin, the degreasing process is very cumbersome and will also cause a large amount of water resources to be wasted, which restricts the utilization of fish skin. Therefore, it is urgent to develop an environmentally friendly fish skin degreasing and extraction technology to improve the utilization rate of fish skin. Summary of the invention

[0004] The purpose of the invention is to provide a method for preparing fish skin protein glue, which can solve the problem that the utilization of fish skin protein glue is limited due to the complicated fish skin degreasing process.

[0005] In order to achieve the above object, the present invention is achieved as follows: In a first aspect, the present invention provides a method for preparing fish skin protein glue, the method comprising: Using fish skin as raw material, the fish skin is subjected to extrusion treatment; The fish skin after the extrusion treatment is subjected to ultrasonic preliminary degreasing treatment and NaHCO3 solution two-step degreasing treatment in sequence; The fish skin after the two-step defatting treatment is subjected to quick freezing and thawing treatment; The fish skin after quick freezing and thawing is subjected to gelatin extraction treatment to obtain fish skin protein glue.

[0006] Furthermore, the ultrasonic preliminary degreasing treatment specifically includes: adding the fish skin after the extrusion treatment into the AEO-9 solution according to the first material-liquid ratio to perform ultrasonic treatment, so as to obtain the fish skin after the ultrasonic preliminary degreasing treatment.

[0007] Furthermore, the first material-liquid ratio is 1 g:5 mL~1 g:10 mL; and the mass fraction of the AEO-9 solution is 0.5%~2%.

[0008] Furthermore, during the ultrasonic treatment process, the ultrasonic treatment power is 100W~300W; and the ultrasonic treatment time is 30min~60min.

[0009] Furthermore, the two-step degreasing treatment with NaHCO3 solution specifically includes: adding the fish skin after the preliminary ultrasonic degreasing treatment into the NaHCO3 solution and soaking it according to the second material-liquid ratio to obtain the fish skin after the two-step degreasing treatment with NaHCO3 solution.

[0010] Furthermore, the second material-liquid ratio is 1g:3mL~1g:5mL; the concentration of NaHCO3 solution is 0.3mol / L~0.8mol / L; and the two-step degreasing treatment time of NaHCO3 solution is 6h~8h.

[0011] Furthermore, during the extrusion process, the extrusion pressure is 300kg~500kg; and the extrusion time is 10min~30min.

[0012] Furthermore, during the quick freezing and thawing process, the quick freezing temperature is -75°C~-80°C, and the quick freezing time is 60min~180min; the thawing temperature is 25°C~35°C, and the thawing time is 60min~180min.

[0013] Furthermore, the gelatin extraction process specifically includes: adding the fish skin after quick freezing and thawing into deionized water, and heating and extracting; wherein, the extraction temperature is 60°C~80°C; and the extraction time is 1h~3h.

[0014] In a second aspect, the present invention provides a fish skin protein glue, which is prepared by the above method.

[0015] The present invention has at least the following beneficial effects: (1) The present invention adopts a two-step degreasing method including ultrasonic preliminary degreasing and NaHCO3 solution two-step degreasing, which has a good degreasing effect.

[0016] (2) The process of the present invention is simple and does not generate pollution during the treatment process, which has the advantages of being green and environmentally friendly.

[0017] (3) The fish skin protein gel extracted by the present invention is transparent and free of impurities and has good gel properties. DETAILED DESCRIPTION

[0018] The technical solutions in the present invention will be described clearly and completely in conjunction with the embodiments below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] An embodiment of the present invention provides a method for preparing fish skin protein glue, the method comprising: Using fish skin as raw material, the fish skin is subjected to extrusion treatment; The fish skin after the extrusion treatment is subjected to ultrasonic preliminary degreasing treatment and NaHCO3 solution two-step degreasing treatment in sequence; The fish skin after the two-step defatting treatment is subjected to quick freezing and thawing treatment; The fish skin after quick freezing and thawing is subjected to gelatin extraction treatment to obtain fish skin protein glue.

[0020] In some embodiments of the present application, in the extrusion process, the extrusion pressure is 300kg~500kg; the extrusion time is 10min~30min, and the purpose of the extrusion process is to preliminarily destroy the fish skin structure, which is conducive to the subsequent degreasing process to produce a better degreasing effect.

[0021] In some embodiments of the present application, the specific steps of ultrasonic preliminary degreasing treatment are adding the fish skin after extrusion treatment to the AEO-9 solution according to the first material-liquid ratio, and ultrasonically treating it to obtain the fish skin after ultrasonic preliminary degreasing treatment.

[0022] In this embodiment, the first material-liquid ratio is 1 g:5 mL to 1 g:10 mL; the mass fraction of the AEO-9 solution is 0.5% to 2%; the ultrasonic treatment power is 100 W to 300 W; and the ultrasonic treatment time is 30 min to 60 min.

[0023] It is worth mentioning that the chemical name of AEO-9 solution is fatty alcohol polyoxyethylene ether (N=9), which is a non-ionic surfactant with strong emulsifying and dispersing effects. It can effectively remove grease and impurities on the surface of fish skin. When using AEO-9 solution and ultrasonic treatment at the same time, the oil layer and cell structure on the surface of fish skin can be destroyed through the action of ultrasonic waves, making it easier for grease to fall off the fish skin, significantly improving the degreasing efficiency and quality. However, the power and duration of ultrasonic treatment should be appropriate to avoid affecting the structure and properties of collagen.

[0024] At the same time, AEO-9 solution does not contain harmful substances such as APEO, is environmentally friendly, has good biodegradability, and can reduce pollution to the environment. Ultrasonic treatment is also a technical means with the advantages of simple operation, low energy consumption, and no pollution.

[0025] In some embodiments of the present application, the specific steps of the two-step degreasing treatment with NaHCO3 solution are to add the fish skin after the preliminary ultrasonic degreasing treatment into the NaHCO3 solution according to the second material-liquid ratio and soak it to obtain the fish skin after the two-step degreasing treatment with NaHCO3 solution.

[0026] In this embodiment, the second material-liquid ratio is 1 g:3 mL~1 g:5 mL; the concentration of the NaHCO3 solution is 0.3 mol / L~0.8 mol / L; and the two-step degreasing treatment time of the NaHCO3 solution is 6 h~8 h.

[0027] It is worth noting that in the degreasing process of fish skin, NaHCO3 solution can react with the oil on the fish skin to produce water-soluble sodium fatty acids and glycerol. These products can be easily washed off the surface of the fish skin, thereby achieving the purpose of degreasing. In addition, NaHCO3 solution can also neutralize the acidic substances on the surface of the fish skin, adjust the pH value, and provide suitable environmental conditions for subsequent treatment. Selecting NaHCO3 solution for two-step degreasing can further remove residual oil and impurities on the fish skin and improve the degreasing effect. At the same time, NaHCO3 solution also has the advantages of low cost, easy access, and environmental friendliness.

[0028] In some embodiments of the present application, in the quick freezing and thawing process of fish skin, the quick freezing temperature is -75°C~-80°C, and the quick freezing time is 60min~180min; the thawing temperature is 25°C~35°C, and the thawing temperature time is 60min~180min.

[0029] It is worth mentioning that the quick freezing process can make the collagen in the fish skin more easily released, thereby improving the extraction efficiency of protein glue. The quick freezing and thawing process can also have a positive effect on the quality of protein glue. For example, by setting the quick freezing and thawing conditions, protein glue with specific physical and chemical properties can be obtained, such as higher gel strength and good stability.

[0030] In some embodiments of the present application, the gelatin extraction process specifically includes: adding the fish skin after quick freezing and thawing into deionized water and heating for extraction; wherein the extraction temperature is 60°C~80°C; and the extraction time is 1h~3h.

[0031] In this embodiment, the control of extraction temperature and time is very important for the yield and quality of protein glue. The purpose of heated extraction is to fully dissolve and release collagen and improve the extraction efficiency of protein glue. Selecting appropriate extraction conditions can also ensure the quality of protein glue and obtain protein glue products with specific physical and chemical properties to meet different application requirements.

[0032] It can be seen that the present invention has at least the following beneficial effects: (1) The present invention adopts a two-step degreasing method including ultrasonic preliminary degreasing and NaHCO3 solution two-step degreasing, which has a good degreasing effect.

[0033] (2) The process of the present invention is simple and does not generate pollution during the treatment process, which has the advantages of being green and environmentally friendly.

[0034] (3) The fish skin protein gel extracted by the present invention is transparent and free of impurities and has good gel properties.

[0035] Some typical embodiments and comparative examples are introduced below.

[0036] Example 1 (1) Extrusion treatment: 98.15 g of fresh fish skin was washed, drained, cut into small pieces of 1 cm × 1 cm, and placed in an extrusion device at an extrusion pressure of 400 kg for 22 min.

[0037] (2) Ultrasonic preliminary degreasing treatment (AEO-9 solution): The extruded fish skin was placed in an AEO-9 solution with a mass fraction of 1% and a solid-liquid ratio of 1 g:5 mL. Ultrasonic treatment was performed at the same time. The ultrasonic treatment power was 250 W and the ultrasonic treatment time was 60 min.

[0038] (3) Two-step degreasing treatment with NaHCO3 solution: After the fish skin has been initially degreased by ultrasonic wave, wash and drain it, then put it into 0.5 mol / L NaHCO3 solution with a solid-liquid ratio of 1 g:4 mL. The soaking time is 6 h, and the NaHCO3 solution is replaced every 2 h. After the soaking is completed, remove the fish skin and wash it until it is neutral.

[0039] (4) Quick freezing and thawing treatment: The fish skin after two-step defatting was placed in a -80℃ refrigerator for quick freezing for 123 minutes, and then quickly placed in 30℃ water for thawing for 122 minutes.

[0040] (5) Extraction of protein glue: The fish skin after quick freezing and thawing was added with deionized water at a solid-liquid ratio of 1 g:4 mL, and extracted in a water bath at 80°C for 3 h. The protein glue solution obtained after filtration with gauze and suction was freeze-dried to obtain a 40.73 protein glue product.

[0041] Example 2 (1) Extrusion treatment: 99.27 g of fresh fish skin was washed, drained, cut into small pieces of 1 cm × 1 cm, and placed in an extrusion device at an extrusion pressure of 400 kg for 21 min.

[0042] (2) Ultrasonic preliminary degreasing treatment (AEO-9 solution): The extruded fish skin was placed in an AEO-9 solution with a mass fraction of 1% and a solid-liquid ratio of 1 g:5 mL. Ultrasonic treatment was performed at the same time. The ultrasonic treatment power was 150 W and the ultrasonic treatment time was 30 min.

[0043] (3) Two-step degreasing treatment with NaHCO3 solution: After the fish skin has been initially degreased by ultrasonic wave, wash and drain it, then put it into a 0.5 mol / L NaHCO3 solution with a solid-liquid ratio of 1 g:4 mL. The soaking time is 6 h, and the NaHCO3 solution is replaced every 2 h. After the soaking is completed, remove the fish skin and wash it until it is neutral.

[0044] (4) Quick freezing and thawing treatment: The fish skin after two-step defatting was placed in a -80℃ refrigerator for quick freezing for 122 minutes, and then quickly placed in 30℃ water for thawing for 121 minutes.

[0045] (5) Extraction of protein glue: The fish skin after quick freezing and thawing was added with deionized water at a solid-liquid ratio of 1 g:4 mL, and extracted in a water bath at 80°C for 3 h. The protein glue solution obtained after filtration through gauze and suction was freeze-dried to obtain 37.33 g of protein glue product.

[0046] Example 3 (1) Extrusion treatment: 100.36 g of fresh fish skin was washed, drained, cut into small pieces of 1 cm × 1 cm, and placed in an extrusion device at an extrusion pressure of 400 kg for 20 min.

[0047] (2) Ultrasonic preliminary degreasing treatment (AEO-9 solution): The extruded fish skin was placed in an AEO-9 solution with a mass fraction of 1% and a solid-liquid ratio of 1 g:5 mL. Ultrasonic treatment was performed at the same time. The ultrasonic treatment power was 250 W and the ultrasonic treatment time was 60 min.

[0048] (3) Two-step degreasing treatment with NaHCO3 solution: After the fish skin has been initially degreased by ultrasonic wave, wash and drain it, then put it into a 0.5 mol / L NaHCO3 solution with a solid-liquid ratio of 1 g:5 mL. The soaking time is 4 h, and the NaHCO3 solution is replaced every 2 h. After the soaking is completed, remove the fish skin and wash it until it is neutral.

[0049] (4) Quick freezing and thawing treatment: The fish skin after two-step defatting was placed in a -80℃ refrigerator for quick freezing for 121 min, and then quickly placed in 30℃ water for thawing for 122 min.

[0050] (5) Extraction of protein glue: The fish skin after quick freezing and thawing was added with deionized water at a solid-liquid ratio of 1 g:4 mL, and extracted in a water bath at 80°C for 3 h. The protein glue solution obtained after filtration through gauze and suction was freeze-dried to obtain 38.59 g of protein glue product.

[0051] Comparative Example 1 (1) Preliminary degreasing treatment: 97.57 g of fresh fish skin was washed and drained, then extracted and degreased in 20% by volume isopropanol at 4 °C for 24 h, washed with water and drained thoroughly. (2) Second-step degreasing treatment: The fish skin after preliminary degreasing was immersed in a 5% sodium chloride solution with a solid-liquid ratio of 1 g:5 ml and stirred continuously for 12 h to remove the impurities in the fish skin. The solution was changed every 2 h, and the fish skin was rinsed with deionized water and drained.

[0052] (3) Quick freezing and thawing treatment: The fish skin after two-step defatting was placed in a -80℃ refrigerator for quick freezing for 121 minutes, and then quickly placed in 30℃ water for thawing for 121 minutes.

[0053] (4) Extraction of protein glue: The fish skin after quick freezing and thawing was soaked in 0.2 mol / L hydrochloric acid solution for 30 min at a solid-liquid ratio of 1 g:5 mL. The skin was washed with water until the pH value was 4-5. Deionized water was added at a solid-liquid ratio of 1 g:4 mL and the skin was extracted in a water bath at 80 °C for 3 h. The protein glue solution obtained after filtration through gauze and suction was freeze-dried to obtain 20.37 g of protein glue product.

[0054] Comparative Example 2 (1) Extrusion treatment: 98.38 g of fresh fish skin was washed, drained, cut into small pieces of 1 cm × 1 cm, and placed in an extrusion device at an extrusion pressure of 400 kg for 21 min.

[0055] (2) Degreasing treatment: The squeezed fish skin is placed in a 0.2 mol / L NaOH solution for degreasing, with a solid-liquid ratio of 1 g:4 ml and a soaking time of 182 min. After soaking, the fish skin is washed until it is neutral.

[0056] (3) Quick freezing and thawing treatment: The fish skin after two-step defatting is placed in a -80℃ refrigerator for quick freezing for 123 minutes, and then quickly placed in 30℃ water for thawing for 120 minutes.

[0057] (4) Extraction of protein glue: The fish skin after quick freezing and thawing was added with deionized water at a solid-liquid ratio of 1 g:4 mL, and extracted in a water bath at 80°C for 3 h. The protein glue solution obtained by filtration with gauze and suction was freeze-dried to obtain 29.63 g of protein glue product.

[0058] Comparative Example 3 (1) Extrusion treatment: 99.73 g of fresh fish skin was washed, drained, cut into small pieces of 1 cm × 1 cm, and placed in an extrusion device at an extrusion pressure of 400 kg for 20.5 min.

[0059] (2) Ultrasonic preliminary degreasing treatment (detergent water): The squeezed fish skin is then placed in a 0.5% by mass detergent water for degreasing, with a material-liquid ratio of 1 g:5 ml, and ultrasonic treatment is performed at the same time, with an ultrasonic power of 250 W and an ultrasonic time of 1 h; (3) After two-step degreasing treatment with NaHCO3 solution for 1 hour, wash the fish skin that has been initially degreased and put it into a 0.5 mol / L NaHCO3 solution with a solid-liquid ratio of 1 g:4 mL. The soaking time is 6 hours, and the NaHCO3 solution is replaced every 2 hours. After the soaking is completed, remove the fish skin and wash it until it is neutral.

[0060] (4) Quick freezing and thawing treatment: The fish skin after two-step defatting was placed in a -80℃ refrigerator for quick freezing for 120 min, and then quickly placed in 30℃ water for thawing for 121 min.

[0061] (5) Extraction of protein glue: The fish skin after quick freezing and thawing was added with deionized water at a solid-liquid ratio of 1 g:4 mL, and extracted in a water bath at 80°C for 3 h. The protein glue solution obtained after filtration through gauze and suction was freeze-dried to obtain 34.63 g of protein glue product.

[0062] Result analysis: The final processing results show that there is basically no oil floating on the surface of the protein glue solution extracted by the method described in Examples 1 to 3, while there is still oil floating on the surface of the protein glue solution extracted by the method described in Comparative Examples 1 to 3.

[0063] The protein glue product obtained by freeze-drying the protein glue solution was weighed, and the yield of fish skin protein glue and the degreasing rate of fish skin were calculated.

[0064] The yield of fish skin protein glue is calculated using the following formula: , Wherein, Yield represents the yield, M represents the weight of the fish skin protein glue after drying (g), and M0 represents the weight of the fish skin (g).

[0065] Fat removal rate: The fat removal rate of fish skin is calculated using the method in GB5009.6-2016 National Food Safety Standard Determination of Fat in Food.

[0066] The yields of fish skin protein glue and the degreasing rates of fish skin of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below.

[0067] Table 1 The yield of fish skin protein glue (%) and the degreasing rate of fish skin (%) By comparing the yield of fish skin protein glue and the degreasing rate of fish skin in Example 1 and Example 2, it can be seen that the ultrasonic treatment power and time will significantly affect the yield of fish skin protein glue and the degreasing rate of fish skin. The ultrasonic treatment power of 250 W and the ultrasonic treatment time of 60 min can produce better degreasing effect and higher fish skin protein glue yield.

[0068] By comparing the yield of fish skin protein glue and the degreasing rate of fish skin in Example 1 and Example 3, it can be seen that the solid-liquid ratio and immersion time of NaHCO3 solution will also significantly affect the yield of fish skin protein glue and the degreasing rate of fish skin. A solid-liquid ratio of 1g:4mL and an immersion time of 6h can produce better degreasing effect and a higher yield of fish skin protein glue.

[0069] By comparing the yield of fish skin protein glue and the degreasing rate of fish skin in Example 1 and Comparative Example 1, it can be seen that whether to use extrusion treatment and two-step degreasing method will also significantly affect the yield of fish skin protein glue and the degreasing rate of fish skin. Compared with the method provided in Comparative Example 1, the method adopted in Example 1 has obviously more significant degreasing effect and higher fish skin yield.

[0070] By comparing the yield of fish skin protein glue and the degreasing rate of fish skin in Example 1 and Comparative Example 2, it can be seen that the choice of degreasing method will also affect the degreasing effect of the method used in Example 1 compared with the method provided in Comparative Example 2, and the fish skin yield is higher.

[0071] By comparing the yield of fish skin protein glue and the degreasing rate of fish skin in Example 1 and Comparative Example 3, it can be seen that the selection of solution type during the ultrasonic preliminary degreasing treatment will also affect the final yield of fish skin protein glue and the degreasing rate of fish skin. Compared with the selection of detergent water with a mass fraction of 0.5%, the selection of AEO-9 solution with a mass fraction of 1% has obviously better degreasing effect and higher fish skin yield.

[0072] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for preparing fish skin protein glue, characterized in that: The method comprises the following steps: Using fish skin as raw material, extruding the fish skin; The fish skin after the extrusion treatment is subjected to ultrasonic preliminary degreasing treatment and NaHCO3 solution two-step degreasing treatment in sequence; The fish skin after the two-step defatting treatment is subjected to quick freezing and thawing treatment; The fish skin after quick freezing and thawing is subjected to gelatin extraction treatment to obtain fish skin protein gelatin.

2. The method according to claim 1, characterized in that The ultrasonic preliminary degreasing treatment specifically includes: The fish skin after the extrusion treatment is added into the AEO-9 solution according to the first material-liquid ratio for ultrasonic treatment to obtain the fish skin after the ultrasonic preliminary degreasing treatment.

3. The method according to claim 2, characterized in that The first material-liquid ratio is 1 g:5 mL to 1 g:10 mL; and the mass fraction of the AEO-9 solution is 0.5% to 2%.

4. The method according to claim 2, characterized in that: During the ultrasonic treatment process, the ultrasonic treatment power is 100W-300W; and the ultrasonic treatment time is 30min-60min.

5. The method according to claim 1, characterized in that The two-step degreasing treatment of NaHCO3 solution specifically includes: The fish skin subjected to the ultrasonic preliminary degreasing treatment is added to the NaHCO3 solution and soaked according to the second material-liquid ratio to obtain the fish skin subjected to the NaHCO3 solution two-step degreasing treatment.

6. The method according to claim 5, characterized in that The second material-liquid ratio is 1g:3mL~1g:5mL; the concentration of the NaHCO3 solution is 0.3mol / L~0.8mol / L; the two-step degreasing treatment time of the NaHCO3 solution is 6h~8h.

7. The method according to any one of claims 1 to 6, characterized in that During the extrusion process, the extrusion pressure is 300kg-500kg; and the extrusion time is 10min-30min.

8. The method according to any one of claims 1 to 6, characterized in that During the quick freezing and thawing process, the quick freezing temperature is -75°C to -80°C, and the quick freezing time is 60min to 180min; the thawing temperature is 25°C to 35°C, and the thawing time is 60min to 180min.

9. The method according to any one of claims 1 to 6, characterized in that The rubber extraction process specifically includes: The fish skin after quick freezing and thawing is added into deionized water and heated for extraction; wherein the extraction temperature is 60° C. to 80° C. and the extraction time is 1 h to 3 h.

10. A fish skin protein glue, characterized in that: The fish skin protein glue is prepared by the method according to any one of claims 1 to 9.

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