High-whiteness high-yield frozen surimi processing technology

Abstract

The present application belongs to the technical field of surimi processing, and discloses a high-whiteness and high-yield frozen surimi processing technology, which mainly comprises the following steps: three times of removing, cleaning, meat picking and primary rotary screen dehydration of raw fish; spiral press water filtration; ice water mixing in meat collecting tank; secondary rotary screen dehydration; fine filtration, dehydration auxiliary ingredient chopping and mixing and quick freezing. The present application does not need to consume a large amount of rinsing water, can greatly save water consumption, reduce factory production cost, does not produce rinsing wastewater, thereby reducing the cost of factory sewage treatment; can fully squeeze out the blood water in fish meat particles, ensure that the fish meat fibers are not damaged, reduce endogenous protease, hemoglobin and lipids in fish meat, and further improve the content of salt-soluble protein in fish meat, so as to improve the gel properties and whiteness of frozen surimi.

Description

Technical Field

[0001] This invention relates to the field of fish paste production and processing, specifically to a high-whiteness, high-yield frozen fish paste processing technology. Background Technology

[0002] The rinsing process, a crucial step in the industrial production of frozen surimi, aims to remove water-soluble proteins such as hemoglobin and cathepsins, as well as lower-density substances like fat and scales, using water as a carrier. This process can improve the purity of surimi myofibrillar proteins to some extent, while simultaneously washing away some endogenous proteases that cause gel deterioration during surimi maturation. This enhances the gel strength of the surimi, giving it good gel properties, improving its sensory quality and whiteness, and reducing quality degradation caused by fat and protein oxidation during frozen storage. However, traditional rinsing processes involve mixing fish meat with 3-5 times its volume of ice water in a rinsing tank, stirring, and then allowing it to stand for a period before draining the top layer of oil and blood. This method not only consumes a large amount of production water but also generates rinsing wastewater, further increasing the company's wastewater treatment burden. In recent years, wastewater treatment has become an increasingly prominent issue in the surimi industry. On the one hand, this processing method not only causes excessive loss of nutrients in the fish meat, but also wastes water resources due to the large amount of rinsing water used. At the same time, the wastewater after rinsing is prone to causing serious environmental pollution. On the other hand, the traditional rinsing process requires the fish meat to stand in the rinsing tank for 5-10 minutes, which prolongs the fish paste processing cycle and reduces production efficiency.

[0003] Application number CN202010392746.7 discloses a continuous surimi production system and a method for preparing surimi. This method uses a horizontal decanter centrifuge to separate the solid and liquid components of harvested fish meat, obtaining fish meat solids and removing water-soluble substances, blood, and a small amount of fat from the fish meat itself. However, the centrifugal force generated by high-speed rotation can cause shear damage to the fish meat, which is detrimental to protein expression after concentration and processing into surimi. Furthermore, the horizontal decanter centrifuge has high construction and maintenance costs, placing pressure on factories in terms of equipment procurement and maintenance. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a high-whiteness, high-yield frozen surimi processing technology, which mainly solves the problems of excessive water consumption, insufficient processing continuity, large equipment footprint, cumbersome employee operation procedures and low automation in existing surimi processing production processes, resulting in low whiteness and low yield of the surimi.

[0005] To address the aforementioned industry challenges, this invention application adopts the following technical solution:

[0006] A high-whiteness, high-yield frozen fish paste processing technology includes the following steps:

[0007] S1. The raw fish is headed, tailed, scaled, and gutted, then cleaned and meated. The meat is mixed with ice water and pumped to the first set of rotary screens by a pumping pump to pre-dehydrate the fish meat 1.

[0008] S2. In step S1, the fish meat 1 is put into a screw press dehydrator for rapid squeezing and filtration to obtain fish meat 2 with a certain water content;

[0009] S3. In step 2, the fish meat 2 is transferred to the meat collection tank by a screw, and ice water is added to mix it to obtain fish meat 3;

[0010] S4. In step 3, the fish meat 3 is pumped to the second set of rotary screens by a pumping pump to pre-dehydrate and obtain fish meat 4.

[0011] S5. In step 4, the fish meat 4 is finely filtered by a fine filter to remove fish skin, fish bones, fish tendons and fish scales and other residues. The finely filtered fish meat is then dehydrated in a dehydrator to obtain fish meat 5.

[0012] S6. In step 5, the fish meat 5 is chopped and mixed with auxiliary materials, then plated and quick-frozen to obtain frozen fish paste.

[0013] Furthermore, in step 2, the filter screen at the feed inlet of the screw press dewatering machine has a mesh size of 2-2.5 mm, and the filter screen at the discharge outlet has a mesh size of 1.3-1.5 mm.

[0014] Furthermore, the screw press dewatering machine described in step 2 has a length of 3-5m, a diameter of 500-700mm, and a length-to-diameter ratio between 5:1 and 8:1.

[0015] Furthermore, in step 2, the compression ratio between the feed end and the discharge end of the screw press dehydration is between 4:1 and 3:1.

[0016] Furthermore, the processing frequency of the screw press dehydrator described in step 2 is 40-60Hz.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] 1. The spiral press dewatering machine used in this invention is different from the traditional rinsing process. It does not require a large amount of rinsing water, which can save water consumption to a great extent, reduce factory production costs, and avoid generating a large amount of rinsing wastewater, thus reducing the cost of wastewater treatment in the factory.

[0019] 2. The spiral press dehydrator used in this invention can fully squeeze out the blood from the fish meat particles, ensuring that the fish meat fibers are not damaged while reducing the endogenous proteases, hemoglobin, and lipids in the fish meat. This, in turn, increases the content of salt-soluble proteins in the fish meat, thereby improving the gel properties and whiteness of the frozen fish paste. Unlike traditional rinsing methods, since no settling is required, the finely chopped fish meat will not be carried away by the rinsing water, increasing the yield of frozen fish paste.

[0020] 3. The screw press dehydrator used in this invention replaces the traditional rinsing tank for processing, achieving continuous dynamic rinsing. This not only allows for timely processing of fish meat and enhances continuous production, but also avoids fish meat remaining on-site and affecting its freshness. Simultaneously, this method uses a screw to rapidly compress the fish meat, increasing the processing rate from approximately 4t / h in the traditional rinsing process to approximately 6t / h in this invention, shortening the overall processing cycle of frozen fish paste. Furthermore, the screw press dehydrator has a high degree of automation, requiring no on-site worker supervision, while the traditional rinsing process often requires 2-3 people to operate the rinsing tanks, increasing labor costs.

[0021] 4. The various process steps in this invention are inseparable and synergistic, forming an indispensable whole. Only under the process conditions of this invention—namely, first rotary screen dehydration, then screw press filtration, ice-water mixing in the meat collection tank, second rotary screen dehydration, fine filtration, dehydration followed by chopping and mixing of auxiliary materials, and quick-freezing—can water consumption be saved, the gel properties, whiteness, and yield of frozen fish paste be improved, the fish meat processing rate be increased, the frozen fish paste processing time be shortened, and production efficiency be improved. The aforementioned processes synergistically save water, improve the whiteness and yield of fish paste, shorten the frozen fish paste processing time, improve production efficiency, and reduce labor costs. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a flowchart of the processing technology of the present invention.

[0024] Figure 2 Comparison chart of whiteness and gel strength of frozen fish paste produced in Examples 1, 2, 3 and Control Example 1. Detailed Implementation

[0025] To better understand the present invention, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. However, those skilled in the art will understand that the following embodiments are not intended to limit the scope of protection of the present invention, and any changes and variations made on the basis of the present invention are within the scope of protection of the present invention.

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0027] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0028] Test method:

[0029] 1. Determination of gel strength and whiteness of frozen fish paste:

[0030] The strength and whiteness of frozen surimi gel were tested according to Appendix A and Appendix B of GB / T 36187-2018, and the results are calculated as average value and standard deviation.

[0031] 2. Calculation of frozen fish paste yield:

[0032] The total mass of the raw fish is W1, the yield of frozen fish paste is W2, and the formula for calculating the yield A of frozen fish paste is:

[0033]

[0034] Example 1

[0035] Reference Figure 1 The above describes a high-whiteness, high-yield frozen fish paste processing technology, which includes the following steps:

[0036] S1. Fresh raw fish are manually headed and tailed, scaled by a scaler, gutted and cleaned, and the meat is mixed with ice water and pumped to the first set of rotary screens for pre-dehydration to obtain fish meat 1.

[0037] S2. In step S1, fish meat 1 is put into a screw press dehydrator for rapid squeezing and dehydration to obtain fish meat 2 with a certain water content;

[0038] S3. In step 2, fish meat 2 is transferred to the meat collection tank by a screw to obtain fish meat 3, which is then mixed with ice water to obtain fish meat 3;

[0039] S4. In step 3, the fish meat 3 is pumped to the second set of rotary screens by a pumping pump to pre-dehydrate and obtain fish meat 4.

[0040] S5. In step 4, the fish meat 4 is filtered by a fine filter to remove fish skin, fish bones, fish tendons and fish scales and other residues. The filtered fish meat is then dehydrated in a dehydrator to obtain fish meat 5.

[0041] S6. In step 5, the fish meat 5 is processed through processes such as chopping and mixing with auxiliary materials, plating and quick-freezing to obtain frozen fish paste.

[0042] In this embodiment, it should be specifically noted that the feed inlet filter screen of the screw press dewatering machine in step S2 has a mesh size of 2mm, and the discharge outlet filter screen has a mesh size of 1.3mm. The screw press dewatering machine is 4m long, 600mm in diameter, and has a length-to-diameter ratio of 7:1. The compression ratio between the screw press dewatering machine cavity and the extrusion screw is 4:1, and the equipment operating frequency is 50Hz. During the auxiliary material chopping stage, the amount of water added is controlled to keep the moisture content of the fish paste within the range of 76-76.5%.

[0043] Example 2

[0044] A high-whiteness, high-yield frozen fish paste processing technology includes the following steps:

[0045] S1. Fresh raw fish are manually headed and tailed, scaled by a scaler, gutted and cleaned, and the meat is mixed with ice water and pumped to a rotary screen for pre-dehydration to obtain fish meat 1.

[0046] S2. In step S1, fish meat 1 is put into a screw press dehydrator for rapid squeezing and dehydration to obtain fish meat 2 with a certain water content;

[0047] S3. In step 2, fish meat 2 is transferred to the meat collection tank by a screw to obtain fish meat 3. Ice water is continuously sprayed above the screw to increase the water content of the fish meat.

[0048] S4. In step 3, the fish meat 3 is pumped to the second set of rotary screens by a pumping pump to pre-dehydrate and obtain fish meat 4.

[0049] S5. In step 4, the fish meat 4 is filtered by a fine filter to remove fish skin, fish bones, fish tendons and fish scales and other residues. The filtered fish meat is then dehydrated in a dehydrator to obtain fish meat 5.

[0050] S6. In step 5, the fish meat 5 is processed through processes such as chopping and mixing with auxiliary materials, plating and quick-freezing to obtain frozen fish paste.

[0051] In this embodiment, it should be specifically noted that the feed inlet filter screen of the screw press dewatering machine in step S2 has a mesh size of 3mm, and the discharge outlet filter screen has a mesh size of 1.7mm. The screw press dewatering machine is 4m long, 600mm in diameter, and has a length-to-diameter ratio of 7:1. The compression ratio between the screw press dewatering machine cavity and the extrusion screw is 4:1, and the equipment operating frequency is 50Hz. During the auxiliary material chopping stage, the amount of water added is controlled to keep the moisture content of the fish paste within the range of 76-76.5%.

[0052] Example 3

[0053] A high-whiteness, high-yield frozen fish paste processing technology includes the following steps:

[0054] S1. Fresh raw fish are manually headed and tailed, scaled by a scaler, gutted and cleaned, and the meat is mixed with ice water and pumped to the first set of rotary screens for pre-dehydration to obtain fish meat 1.

[0055] S2. In step S1, fish meat 1 is put into a screw press dehydrator for rapid squeezing and dehydration to obtain fish meat 2 with a certain water content;

[0056] S3. In step 2, fish meat 2 is transferred to the meat collection tank by a screw to become fish meat 3. Ice water is continuously sprayed above the screw to increase the water content of the fish meat.

[0057] S4. In step 3, the fish meat 3 is pumped to the second set of rotary screens by a pumping pump to pre-dehydrate and obtain fish meat 4.

[0058] S5. In step 4, the fish meat 4 is filtered by a fine filter to remove fish skin, fish bones, fish tendons and fish scales and other residues. The filtered fish meat is then dehydrated in a dehydrator to obtain fish meat 5.

[0059] S6. In step 5, the fish meat 5 is processed through processes such as chopping and mixing with auxiliary materials, plating and quick-freezing to obtain frozen fish paste.

[0060] In this embodiment, it should be specifically noted that the feed inlet filter screen of the screw press dewatering machine in step S2 has a mesh size of 2mm, and the discharge outlet filter screen has a mesh size of 1.3mm. The screw press dewatering machine is 2m long, 500mm in diameter, and has a length-to-diameter ratio of 4:1. The compression ratio between the screw press dewatering machine cavity and the extrusion screw is 4:1, and the equipment operating frequency is 50Hz. During the auxiliary material chopping stage, the amount of water added is controlled to keep the moisture content of the fish paste within the range of 76-76.5%.

[0061] Compare with Example 1

[0062] The traditional frozen fish paste rinsing process uses the following steps:

[0063] Fresh raw fish undergoes manual head and tail removal, scale removal using a scaler, manual scrubbing of the internal organs and black membrane, and bubbling cleaning. Following this, the fish meat is processed into fillets. The fillets are mixed with ice water and pumped through a slurry pump to a first-stage rotary screen for filtration, then into a rinsing tank. Ice water is added simultaneously until the tank is full. The stirring blades are then turned off, and the mixture is left to stand for 10 minutes to remove the top layer of floating oil and blood. Filtration is stopped when the fillets are visible. The fillets are then pumped through a slurry pump to a second-stage rotary screen for further filtration. After this second filtration, the fillets are further filtered in a fine filter and then transferred to a dehydrator for dehydration. The dehydrated fish meat is then chopped with auxiliary ingredients, trayed, and quick-frozen to obtain frozen fish paste. During the auxiliary ingredient chopping stage, the amount of water added is controlled to maintain the fish paste's moisture content within the range of 76-76.5%.

[0064] The gel strength and whiteness of the frozen fish paste produced in Examples 1, 2, 3, and Control Example 1 were measured, and the results are as follows: Figure 2 As shown. From Figure 2 As can be seen, the gel strengths of the frozen fish paste produced in Examples 1, 2, 3, and Control Example 1 were 395.5 g·cm, 375.2 g·cm, 368.1 g·cm, and 320.7 g·cm, respectively, and the whitenesses were 55.1, 53.3, 53.4, and 52.2, respectively. Compared with Control Example 1, the production methods of Examples 1-3 can improve the gel strength and whiteness of frozen fish paste to a certain extent, thereby giving the fish paste products better texture and color. Unlike Control Example 1, which used a large amount of ice water to mix and stir the fish meat and then let it stand to dissolve the hemoglobin and other coloring substances in the fish meat, and separated the blood and water from the fish meat by the sedimentation of the fish meat itself, thereby improving the whiteness of the fish meat and reducing substances such as cathepsins in the fish meat that are not conducive to the formation of fish paste gel. In Examples 1-3, a variable-diameter screw and a mesh screen with smaller apertures are used to create a gradual compression environment, which moderately squeezes the fish meat. This can promote the rupture of capillaries near the muscle cells of the fish meat to a certain extent, thereby promoting the dissolution of hemoglobin into the free water of the fish meat cells. This further removes water-soluble proteins such as hemoglobin and myoglobin from the fish meat, resulting in a better effect on improving the whiteness of the fish meat and reducing the action of tissue proteases during the surimi gel formation stage. Therefore, physical extrusion is superior to the method of analyzing the separation of fish meat and blood by weight. In Example 2, because the filter screen at the inlet of the screw press dehydrator has a pore size of 3mm and the filter screen at the outlet has a pore size of 1.7mm, the larger pore size leads to poor extrusion of some fish meat, resulting in poor separation of blood and water, and consequently, lower surimi gel strength and whiteness. In Example 3, the screw press dehydrator is 2m long and 500mm in diameter with a length-to-diameter ratio of 4:1. The fish meat is processed for a shorter time in the screw press dehydrator, and the fish meat is not fully squeezed in the cavity, resulting in incomplete blood extraction. This causes the gel strength and whiteness of the finished fish paste to decrease compared to the fish paste in Example 1.

[0065] Table 1 shows the yield and water consumption per ton of frozen fish paste produced using four processing methods: Example 1, Example 2, Example 3, and Comparative Example 1. Compared to the traditional rinsing process used in Comparative Example 1, which removes the surface oil and blood, resulting in the loss of finely chopped fish meat and fat, the processing methods in Examples 1-3 can retain the fat in the fish meat to a certain extent, further improving the yield of frozen fish paste. On the other hand, fish meat processed using the traditional rinsing process absorbs a large amount of water and expands during the settling stage in ice water, resulting in fish meat with a high water content. This requires more time for dehydration in the subsequent stage, and prolonged compression of the fish meat in the dehydrator causes some small pieces of fish meat to escape from the filter mesh, resulting in the loss of fish meat protein, which reduces the yield of fish paste to a certain extent and causes economic losses. At the same time, in Comparative Example 1, a large amount of ice water is required to mix and stir the fish meat during the rinsing stage, resulting in an average water consumption per ton of fish paste that is higher than in Examples 1-3.

[0066] Table 1. Yield and water consumption per ton of fish paste under four processing modes

[0067]

[0068]

[0069] In summary, the various process steps in this invention are inseparable and synergistic, forming an indispensable whole. Only under the process conditions of this invention—namely, a first rotary screen pre-dehydration, followed by screw pressing filtration, ice-water mixing in the meat collection tank, a second rotary screen pre-dehydration, fine filtration, dehydration, chopping and mixing of auxiliary materials, and quick-freezing—can water consumption be saved, the gel properties, whiteness, and yield of frozen fish paste be improved, the fish meat processing rate be increased, the frozen fish paste processing time be shortened, and production efficiency be improved. The aforementioned processes work synergistically, effectively saving water consumption, improving the whiteness and yield of fish paste, shortening the frozen fish paste processing time, increasing production efficiency, and reducing labor costs.

[0070] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A high-whiteness, high-yield frozen fish paste processing technology, comprising the following steps: S1. The raw fish is headed, tailed, scaled, and gutted, then cleaned and meated. The meat is mixed with ice water and pumped to the first set of rotary screens by a pumping pump to pre-dehydrate the fish meat 1. S2. In step S1, the fish meat 1 enters the screw press dehydrator and is quickly squeezed and filtered to obtain fish meat 2 with a certain water content. The screw press dehydrator has a filter screen with a mesh size of 2mm at the feed port and a filter screen with a mesh size of 1.3mm at the discharge port. It is 4m long, 600mm in diameter, and has a length-to-diameter ratio of 7:

1. The compression ratio between the feed port and the discharge port of the screw press dehydrator is 4:

1. S3. In step 2, the fish meat 2 is transferred to the meat collection tank by a screw, and ice water is added to mix it to obtain fish meat 3; S4. In step 3, the fish meat 3 is pumped to the second set of rotary screens by a pumping pump to pre-dehydrate and obtain fish meat 4. S5. In step 4, the fish meat 4 is finely filtered by a fine filter to remove fish skin, fish bones, fish tendons and fish scale residue. The finely filtered fish meat is then dehydrated in a dehydrator to obtain fish meat 5. S6. In step 5, the fish meat 5 is chopped and mixed with auxiliary materials, then plated and quick-frozen to obtain frozen fish paste.

2. The frozen fish paste processing technology according to claim 1, characterized in that, The processing frequency of the screw press dehydrator in step 2 is 40-60Hz.

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