A method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology

Abstract

The present invention belongs to the field of food technology, and in particular to a method for recovering protein in fish paste rinsing waste liquid based on low-temperature plasma technology. First, fish meat is taken and fish paste is obtained by chopping and mixing; the fish paste is added to water for mixing and rinsing, and the supernatant obtained by centrifugation is the fish paste rinsing liquid; then the input power of the plasma device is adjusted to 300-800W, the muzzle of the plasma device is placed below the liquid level of the fish paste rinsing liquid, the power is turned on, and air is used as the gas source to excite the plasma so that the plasma acts evenly on the fish paste rinsing liquid, and the processing time is 2-6min; the treated rinsing liquid is centrifuged to obtain a precipitate after standing in an environment with a temperature of less than 10°C, i.e., the recovery of protein in the fish paste rinsing liquid is realized. The present invention utilizes low-temperature plasma to treat the fish paste rinsing liquid, improves the recovery rate of protein, reduces the process flow of protein recovery, and avoids secondary pollution in the recovery process, with broad application prospects.

Description

Technical Field

[0001] The invention belongs to the field of food technology, and in particular relates to a method for recovering protein from fish paste rinsing waste liquid based on low-temperature plasma technology. Background Art

[0002] In recent years, surimi products have become increasingly popular with consumers due to their high protein content, low fat content, and tender, refreshing taste. Surimi products are made from frozen surimi, which is crushed, formed, and gelled to create a gel-like food with a certain elasticity. Surimi is made from fish meat, which is then processed through meat extraction, rinsing, fine filtering, dehydration, chopping, and freezing. Traditional surimi processing requires rinsing, which removes fishy substances, pigments, fat, and some inorganic salts from the fish, improving the gel properties and increasing whiteness. However, rinsing also causes the loss of nutrients such as water-soluble protein, fat, and inorganic salts. The protein lost during rinsing accounts for approximately one-third of the water-soluble protein in fish. Furthermore, rinsing consumes a lot of water. According to statistics, the production of one ton of surimi products generates approximately eight tons of rinsing liquid. The resulting wastewater must also be treated before it can be discharged, increasing production costs. Recycling protein from rinsing wastewater can reduce resource waste, improve the utilization rate of by-products in surimi processing, and reduce environmental pollution, which has certain economic and environmental benefits.

[0003] Currently, the main methods for recovering protein from surimi rinses include membrane separation, flocculation, and isoelectric precipitation. Comparing the three methods, membrane separation has a better recovery effect, but there is the problem of membrane contamination; flocculation is simple to operate and has a high recovery rate, but there are problems such as flocculants causing secondary contamination in the subsequent processing of the recovered protein and high costs during use; and isoelectric precipitation has the advantages of simple operation and low price, but the recovery effect is poor.

[0004] As an emerging non-thermal processing technology, low-temperature plasma has been applied to wastewater treatment. It is considered to be a friendly and green technical means. It only requires discharge equipment and air to treat water bodies and has no side effects on water bodies. Therefore, this technology is a research hotspot in wastewater treatment, but there are currently few reports on its application in protein. Summary of the Invention

[0005] The present invention treats the surimi rinsing liquid with low-temperature plasma for different times, and objectively evaluates the feasibility of the method according to the protein recovery rate.

[0006] The present invention includes the procedures of preparing surimi rinsing liquid, treating the rinsing liquid with low-temperature plasma, recovering protein precipitation, and data processing. The specific operation steps are as follows:

[0007] A method for recovering protein from surimi rinse liquid using plasma is carried out according to the following steps:

[0008] (1) Minced fish: minced fish meat is minced and mixed to make minced fish;

[0009] (2) Preparation of surimi rinse liquid: surimi is added to water for mixing and rinsing, and then centrifuged to obtain the supernatant, which is the surimi rinse liquid;

[0010] (3) Low-temperature plasma treatment of the surimi rinsing liquid: First, adjust the parameters of the plasma equipment and set the input power to 300-800W. Then, place the muzzle of the plasma equipment below the liquid level of the surimi rinsing liquid, turn on the power, use air as the gas source, and excite the plasma so that the plasma acts evenly on the surimi rinsing liquid. The treatment time of the surimi rinsing liquid is 2-6 minutes.

[0011] (4) Protein recovery: The rinse liquid after low-temperature plasma treatment is allowed to stand in an environment with a temperature below 10°C and then centrifuged. The precipitate obtained after centrifugation is collected to achieve protein recovery in the surimi rinse liquid.

[0012] Preferably, the ratio of surimi to water in step (2) is 1 g:5 mL; the water is distilled water.

[0013] Preferably, the rinsing time in step (2) is 5-10 minutes.

[0014] Preferably, the centrifugal conditions in step (2) are: 8000 r / min at 4° C., for 10-15 min.

[0015] Preferably, the processing parameter in step (3) is an output power of 300-800W.

[0016] Preferably, the height of the rinsing liquid in step (3) is 15-20 cm.

[0017] Preferably, in step (3), the muzzle is fixed 10-15 mm below the level of the rinse liquid.

[0018] Preferably, the processing time in step (3) is optimally 4 minutes.

[0019] Preferably, the standing temperature in step (4) is preferably 0-4°C, and the standing time is 6 hours.

[0020] Preferably, the centrifugation condition in step (4) is: centrifugation at 8000 r / min for 10-15 min at 4°C.

[0021] Determination of protein recovery rate: The supernatant obtained by centrifugation in step (4) was placed in a 20°C water bath and allowed to stand for 90 minutes, then centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected to measure the protein concentration; finally, the protein concentrations in the original rinse solution and the supernatant were determined by the biuret method. The protein recovery rate was calculated as follows:

[0022]

[0023] Where: C0 is the protein concentration in the original surimi rinse, mg / mL; C1 is the protein concentration in the supernatant, mg / mL.

[0024] Finally, the protein recovery rate was used to evaluate the effect of low-temperature plasma treatment on protein recovery in surimi rinse liquid.

[0025] Beneficial effects:

[0026] The present invention utilizes low-temperature plasma technology to precipitate and recover protein in the surimi rinsing liquid after preparing the surimi rinsing liquid. Compared with the traditional method for recovering protein in the surimi rinsing liquid, the surimi rinsing liquid is directly treated by low-temperature plasma equipment, thereby increasing the recovery rate of protein in the surimi rinsing liquid, shortening the process flow of protein recovery, and improving the efficiency of protein recovery (the highest protein recovery rate after treating the rinsing waste liquid with low-temperature plasma is 88.23%), avoiding secondary pollution in the recovery process, being green and environmentally friendly, and providing a feasible method for recovering by-products in the industrial production of surimi, thereby further realizing high-value production of surimi.

[0027] Low-temperature plasma treatment can effectively improve the recovery rate of protein in surimi rinsing liquid, but its treatment time is crucial; when the low-temperature plasma treatment time is 2-4 minutes, as the low-temperature plasma treatment time increases, the protein recovery rate increases from 79.63% to 88.23%, an increase of 8.6%. This is because after the surimi rinsing liquid is treated with low-temperature plasma, active ingredients will be produced in the rinsing liquid, which will cause the protein in the rinsing liquid to oxidize. Oxidation causes the protein structure to unfold and the hydrophobic amino acids on the protein surface are exposed, causing the surface hydrophobicity of the protein to change. As the low-temperature plasma treatment time increases, the low-temperature plasma treatment time increases. The active ingredients produced in the process enhance the attachment of water micelles to protein molecules, increase the hydrophobicity of the protein surface, help induce protein-protein interaction, thereby promoting the formation of protein aggregates and improving the precipitation recovery rate of the protein; on the other hand, when the low-temperature plasma treatment time is extended from 4 min to 6 min, the protein recovery rate decreases with the increase of low-temperature plasma treatment time, decreasing by 9.97%. This is because as the low-temperature plasma treatment time of fish paste rinsing liquid increases, it causes excessive oxidation of the protein in the rinsing liquid, which has a negative impact on the aggregation stability of the protein, causes the protein aggregates to break, and reduces the protein precipitation recovery rate. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope. Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art of the present invention. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of conflict with any incorporated document, the content of this specification shall prevail.

[0030] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0031] The raw material used for preparing the fish paste is fresh silver carp purchased from Zhenjiang RT-Mart Supermarket.

[0032] Example 1:

[0033] The present invention includes the following procedures: preparation of surimi rinsing liquid, low-temperature plasma treatment of the rinsing liquid, protein precipitation recovery, data processing, etc. The specific production process is as follows:

[0034] A method for recovering protein from surimi rinse liquid using plasma is carried out according to the following steps:

[0035] (1) Surimi: knock silver carp unconscious, peel and remove boneless fish meat manually, and chop with a chopper for 3 minutes to obtain surimi;

[0036] (2) Preparation of surimi rinse solution: surimi was mixed with distilled water at a ratio of 1:5 (w / v, g / mL) and rinsed for 5 min. The mixture was centrifuged at 8000 rpm for 15 min at 4°C. The supernatant was used as the surimi rinse solution.

[0037] (3) Low-temperature plasma treatment of the surimi rinsing liquid: Use a PG-1000ZD low-temperature plasma spray gun device, adjust the parameters of the plasma device, set the input power to 500 W, place the surimi rinsing liquid under the muzzle of the plasma device, fix the muzzle of the device 10 mm below the horizontal surface of the rinsing liquid, turn on the power, use air as the gas source, excite the plasma, and allow the plasma to act evenly on the surimi rinsing liquid. Under this condition, treat the rinsing liquid for 2 min;

[0038] (4) Protein recovery: The rinse liquid after low-temperature plasma treatment was allowed to stand for 6 h at 4°C and then centrifuged. The relevant conditions were: centrifugation at 8000 r / min for 15 min at 4°C, and the precipitate obtained after centrifugation was collected to achieve protein recovery in the surimi rinse liquid.

[0039] (5) The supernatant obtained by centrifugation in step (4) was placed in a 20°C water bath and allowed to stand for 90 minutes, then centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected to measure the protein concentration; finally, the protein concentrations in the original rinse solution and the supernatant were determined by the biuret method, and the protein recovery rate was calculated as follows:

[0040]

[0041] Where: C0 is the protein concentration in the original surimi rinse, mg / mL; C1 is the protein concentration in the supernatant, mg / mL.

[0042] (6) The protein recovery rate was determined to be 79.63%.

[0043] Example 2:

[0044] The present invention includes the following procedures: preparation of surimi rinsing liquid, low-temperature plasma treatment of the rinsing liquid, protein precipitation recovery, data processing, etc. The specific production process is as follows:

[0045] A method for recovering protein from surimi rinse liquid using plasma is carried out according to the following steps:

[0046] (1) Fish surimi: knock silver carp unconscious, remove the skin and remove the boneless fish meat manually, and chop it with a chopper for 3 minutes to obtain fish surimi.

[0047] (2) Preparation of surimi rinse solution: surimi was rinsed with distilled water at a ratio of 1:5 (w / v, g / mL) for 5 min, centrifuged at 8000 rpm for 15 min at 4°C, and the supernatant was used as the surimi rinse solution.

[0048] (3) Low-temperature plasma treatment of the surimi rinsing liquid: Use a PG-1000ZD low-temperature plasma spray gun device, adjust the parameters of the plasma device, set the input power to 500 W, place the surimi rinsing liquid under the muzzle of the plasma device, fix the muzzle of the device 10 mm below the horizontal surface of the rinsing liquid, turn on the power, use air as the gas source, excite the plasma, and allow the plasma to act evenly on the surimi rinsing liquid. Under this condition, treat the rinsing liquid for 4 min;

[0049] (4) Protein recovery: The rinse liquid after low-temperature plasma treatment was allowed to stand for 6 h at 4°C and then centrifuged at 8000 r / min for 15 min at 4°C. The precipitate obtained after centrifugation was collected to achieve protein recovery in the surimi rinse liquid.

[0050] (5) The supernatant obtained by centrifugation in step (4) was placed in a 20°C water bath and allowed to stand for 90 minutes, then centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected to measure the protein concentration; finally, the protein concentrations in the original rinse solution and the supernatant were determined by the biuret method, and the protein recovery rate was calculated as follows:

[0051]

[0052] Where: C0 is the protein concentration in the original surimi rinse, mg / mL; C1 is the protein concentration in the supernatant, mg / mL.

[0053] (6) The protein recovery rate was determined to be 88.23%.

[0054] Example 3:

[0055] The present invention includes the following procedures: preparation of surimi rinsing liquid, low-temperature plasma treatment of the rinsing liquid, protein precipitation recovery, data processing, etc. The specific production process is as follows:

[0056] A method for recovering protein from surimi rinse liquid using plasma is carried out according to the following steps:

[0057] (1) Surimi: Buy fresh silver carp from supermarkets, knock them unconscious, peel them, and remove the boneless fish meat by hand. Chop them in a chopper for 3 minutes to obtain surimi.

[0058] (2) Preparation of surimi rinse solution: surimi was rinsed with distilled water at a ratio of 1:5 (w / v, g / mL) for 5 min, centrifuged at 8000 rpm for 15 min at 4°C, and the supernatant was used as the surimi rinse solution.

[0059] (3) Low-temperature plasma treatment of the surimi rinsing liquid: Use a PG-1000ZD low-temperature plasma spray gun device, adjust the parameters of the plasma device, set the input power to 500 W, place the surimi rinsing liquid under the muzzle of the plasma device, and fix the muzzle of the device 10 mm below the horizontal surface of the rinsing liquid; turn on the power, use air as the gas source, excite the plasma, and allow the plasma to act evenly on the surimi rinsing liquid. Under this condition, treat the rinsing liquid for 6 min.

[0060] (4) Protein recovery: The rinse liquid after low-temperature plasma treatment was allowed to stand for 6 h at 4°C and then centrifuged at 8000 r / min for 15 min at 4°C. The precipitate obtained after centrifugation was collected to achieve protein recovery in the surimi rinse liquid.

[0061] (5) The supernatant obtained by centrifugation in step (4) was placed in a 20°C water bath and allowed to stand for 90 minutes, then centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected to measure the protein concentration; finally, the protein concentrations in the original rinse solution and the supernatant were determined by the biuret method, and the protein recovery rate was calculated as follows:

[0062]

[0063] Where: C0 is the protein concentration in the original surimi rinse, mg / mL; C1 is the protein concentration in the supernatant, mg / mL.

[0064] (6) The protein recovery rate was determined to be 78.26%.

[0065] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Therefore, although this specification has described the present invention in detail with reference to the above embodiments, it should be understood by those skilled in the art that the present invention may still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology, characterized in that: The following steps are involved: (1) Take fish meat and chop and mix it to make fish paste; (2) Preparation of surimi rinsing liquid: add surimi into water for mixing and rinsing, then centrifuge to obtain the supernatant, which is the surimi rinsing liquid; (3) Low-temperature plasma treatment of surimi rinsing liquid: First, adjust the parameters of the plasma equipment and set the input power to 300-800 W. Then, place the muzzle of the plasma equipment below the liquid level of the surimi rinsing liquid, turn on the power, use air as the gas source, and excite the plasma so that the plasma acts evenly on the surimi rinsing liquid. The treatment time of the surimi rinsing liquid is 2-6 minutes. (4) Protein recovery: The rinse liquid after low-temperature plasma treatment is allowed to stand in an environment with a temperature below 10°C and then centrifuged. The precipitate obtained after centrifugation is collected to achieve protein recovery in the surimi rinse liquid.

2. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: In step (2), the ratio of surimi to water is 1 g:5 mL; the water is distilled water.

3. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: The rinsing time in step (2) is 5-10 min.

4. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: The centrifugal conditions in step (2) are: 8000 r / min at 4°C for 10-15 min.

5. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: The height of the rinsing liquid in step (3) is 15-20 cm.

6. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: In step (3), the muzzle is fixed 10-15 mm below the level of the rinse liquid.

7. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: The processing time in step (3) is 4 min.

8. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: The standing temperature in step (4) is 0-4°C and the standing time is 6 h.

9. The method for recovering protein from surimi rinsing wastewater based on low-temperature plasma technology according to claim 1, characterized in that: The centrifugal conditions in step (4) are: 8000 r / min at 4°C for 10-15 min.

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