A method for processing grilled fish fillets

Abstract

The application discloses a kind of grilled fish processing method, belong to aquatic product processing field.The traditional grilled fish is prone to curling and breaking, dry and hard in taste, and has no identification problem, the present application provides the following scheme: raw material fish is ground into minced meat after being cut and debarbed, filled into mold and compressed into shape under pressure;Under-18 DEG C to-30 DEG C, quick freezing and setting for 1-4 hours;After taking out, brush oil, bake both sides at 135 DEG C-145 DEG C low temperature;Natural air-drying for 10-20 minutes;Mechanical pressure loose with grooved opposite rotating pull loose roller, make fish muscle fiber puffy;Finally, use 370 DEG C-400 DEG C high temperature soldering iron to imprint text or pattern on the surface.The application is prepared by compression, freezing pore, physical texture reconfiguration technology of loose, and the fish piece shape is complete, the taste is crisp and loose, and has clear and durable identification.

Description

Technical Field

[0001] This invention relates to the field of deep processing technology for aquatic products, specifically to a method for processing grilled fish slices. Background Technology

[0002] Grilled fish slices have become an important category in the snack food market due to their high quality protein, unsaturated fatty acids, and portability. Currently, the mainstream processing technology for commercially available grilled fish slices (such as application publication number 102450693A) is: raw material thawing → pre-treatment → slicing → deodorizing → seasoning → high-temperature baking → packaging.

[0003] However, the above-mentioned traditional process has the following technical defects that are difficult to overcome: (1) Poor morphological integrity: The fish slices cut directly are of uneven thickness, and the rate of moisture evaporation is inconsistent during high-temperature baking, resulting in severe curling, scorching of the edges, or even breakage of the fish slices. The yield is usually only 70%-85%; (2) Deterioration of taste: The traditional process uses direct high-temperature baking at 150℃-250℃, which causes the fish muscle fibers to lose water and shrink rapidly, and the protein to denature excessively, resulting in a dry and hard texture and difficulty in chewing, which is especially unsuitable for the elderly and children; (3) Loss of nutrients: High-temperature baking for a long time causes a large amount of heat-sensitive nutrients (such as EPA, DHA, and taurine) in the fish slices to be oxidized and decomposed; (4) Serious homogenization of products: The existing products have a single appearance and lack effective anti-counterfeiting and brand identification methods.

[0004] To address the above issues, the industry has tried adding phosphate water-retaining agents or oils to improve the taste, but the effects are limited and introduce additional chemical additives. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of the prior art and provide a method for processing grilled fish fillets. This invention involves grinding and recombining fish meat, compressing and shaping it, combined with freeze-drying microcrystallization, gradient temperature-controlled grilling, and mechanical stretching. This process rearranges the fish muscle fibers to form a loose, porous structure, ultimately resulting in grilled fish fillets that are regularly shaped, crispy, retain high nutritional value, and have clear branding markings.

[0006] To achieve the above objectives, a method for processing grilled fish fillets is provided, comprising the following steps: S1: Slicing and Deboning: After removing the skin, scales, and internal organs of the raw fish, fillet the fish along the spine from both sides of the body and remove the bones. There are no strict restrictions on the type of raw fish. Generally, larger fish are used as raw fish to facilitate slicing, such as cod, mullet, filefish, and pomfret, but they are not limited to these.

[0007] S2: Grinding and Mincing: Put the cleaned fish fillets obtained in step S1 into a meat grinder or colloid mill and grind them into a minced state. Control the degree of grinding so that the diameter of the fish meat particles is no larger than 2-5mm. During the grinding process, the material temperature must be kept ≤10℃ to prevent protein denaturation.

[0008] S3: Compression Molding: The ground fish paste is filled into the molding mold according to the predetermined weight. A pressure of 0.5-2 MPa is applied by hydraulic or mechanical pressure blocks to compact the paste and hold the pressure for 10-30 seconds to produce compressed raw fish slices of uniform thickness. Through compression, the fish muscle fibers are physically compressed, internal air bubbles are expelled, and a dense and uniform embryo is formed.

[0009] S4: Freezing and Microcrystallization: The compressed fish fillets, along with the mold, are placed in a freezer for quick freezing and shaping. The freezing temperature is controlled at -18℃ to -30℃, and the freezing time is 1-4 hours. Preferably, the freezing rate is 5-10℃ / min.

[0010] The ice crystals formed below -18℃ are fine and uniform microcrystals (diameter <50μm), which will not puncture the cell wall and can form a uniform ice crystal network skeleton inside the fish fillet. This skeleton melts during the subsequent baking process, creating uniform capillary channels inside the fish fillet, while ensuring that the fish fillet maintains a perfect geometric shape during thawing and transfer, and prevents curling.

[0011] S5: Thawing and oiling: Remove the frozen and shaped fish fillets from the mold. They do not need to be completely thawed. Spread them directly on the heating conveyor platform of the fish grilling machine. Brush a layer of vegetable oil (such as soybean oil, olive oil or rapeseed oil) evenly on the surface of the fish fillets. The amount of oil should be 1%-3% of the weight of the fish fillets.

[0012] S6: Gradient Temperature Control Baking: Set the heating platform temperature of the fish grill to 135℃-145℃. First, place the fish fillets with one side facing the heating source and bake for 3-8 minutes, then flip them over and bake for another 3-8 minutes on the other side. Low-temperature slow baking ensures that the fish fillets are heated evenly inside and out, preventing the surface from burning too quickly. The internal moisture evaporates slowly, and combined with the microporous network formed by freezing, the fish meat tissue slowly unfolds.

[0013] S7: Evenly dry: Take out the roasted fish fillets and place them on a well-ventilated and clean drying rack to air dry naturally for 10-20 minutes. This allows excess oil on the surface of the fish fillets to evaporate and the residual moisture inside the fish fillets to be redistributed evenly, preventing the outside from being dry while the inside is still wet.

[0014] S8: Mechanical loosening: The dried fish fillets are fed into a loosening processing device. The loosening processing device includes two opposing fixed frames and a first loosening roller and a second loosening roller arranged from top to bottom between the two fixed frames. The two ends of the first loosening roller and the second loosening roller are respectively mounted on the two fixed frames through bearings. One end of the first loosening roller is fixedly connected to a first gear, and the same end of the second loosening roller is fixedly connected to a second gear. The first gear and the second gear mesh with each other. The first loosening roller is connected to a drive motor, which drives the first loosening roller to rotate and drives the second loosening roller to rotate in the opposite direction through gear meshing. One end of the second loosening roller extends to the outside of the second gear and is fixedly connected to a handle. Several radial grooves are equidistantly opened on the surface of the two rollers along the axial direction. When the two rollers rotate in opposite directions, the fish fillets are subjected to periodic compression and release, and the muscle fibers are torn into a fluffy filamentous structure. The volume of the fish fillets expands by 20%-40%, and the texture changes from hard to loose.

[0015] S9: High-Temperature Branding: The special branding iron is heated to 370℃-400℃. The working surface of the branding iron is provided with raised pre-set text (such as "Dalian" or "Seafood") or specific graphics (such as waves or fish shapes). The branding iron is pressed vertically down, so that the raised surface makes close contact with the surface of the fish fillet for 3-10 seconds. The high temperature causes the protein on the contact surface to caramelize and carbonize instantly, forming a clear dark brown mark, which has the advantages of being durable, non-fading, and not staining the packaging bag.

[0016] Preferably, in step S6, to enhance the flavor, a seasoning liquid can be sprayed onto the surface of the fish fillets before or during baking. The seasoning liquid contains 5%-15% white sugar, 2%-5% salt, and natural spice extracts.

[0017] Preferably, in step S8, the depth of the radial groove is 2-5 mm, the spacing is 5-10 mm, and the rotational linear speed of the stretching roller is 5-20 m / min.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Zero breakage and perfect slice shape: Through the physical locking technology of "grinding and reorganization and freezing and shaping", the problem of fish slice edge curling and breakage in the traditional slicing process is completely eliminated, and the finished product slice integrity rate can reach more than 98%; (2) Crispy and melt-in-your-mouth texture: By using the composite texture reconstruction technology of "microcrystalline ice core pore making and mechanical roller pressing and loosening", the original dense and hard fish protein network is transformed into a loose and porous fiber cluster structure, making the product crispy and melt-in-your-mouth, solving the problem of difficulty in eating for the elderly and children. (3) High nutrient retention: The mild baking temperature of 135-145℃, combined with freezing pretreatment, effectively reduces the thermal oxidation loss of unsaturated fatty acids (EPA / DHA) in fish meat. Compared with traditional processes, the nutrient retention rate is significantly improved. (4) It has both anti-counterfeiting and branding functions: the carbonized mark formed by high temperature branding is clear, beautiful and durable. It can be used as a corporate trademark or place of origin mark, and has both brand promotion and anti-counterfeiting traceability functions, which greatly enhances the added value of the product. Attached Figure Description

[0019] Figure 1 This is an overall flow chart of the compression molding process for roasted fish fillets according to the present invention; Figure 2 This is a schematic diagram of the structure of the stretching device used in step S8 of the present invention; Figure 3 This is a perspective view of the soldering iron head in step S9 of the present invention; Figure 4 This is a schematic diagram of the grilled fish slices product of the present invention; In the figure, 1-fixed frame, 2-first pull roller, 3-second pull roller, 4-first gear, 5-second gear, 6-drive motor, 7-handle, 8-radial groove, 9-soldering iron body, 10-protrusion. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Example 1 Please see Figures 1-4 As shown, the purpose of this solution is to provide a method for processing grilled fish fillets, including the following steps: S1: Slicing and deboning: Take frozen cod and thaw it at 4℃ for 12 hours. Remove the head, skin, scales, and internal organs. Take the white meat from the back and manually remove the fine bones to obtain clean fish fillets.

[0023] S2: Grinding and mincing: Place the cleaned fish fillets into a meat grinder with a perforated plate diameter of 4mm and grind them 3 times to obtain fine fish mince. The material temperature is controlled below 8℃ throughout the grinding process.

[0024] S3: Compression molding: Take 150g of fish paste, fill it into a stainless steel mold, press it with 1MPa pressure for 15 seconds, and compact it into shape.

[0025] S4: Freezing and microcrystal shaping: The mold is sent into a quick-freezing chamber and cooled to -25°C at a rate of 8°C / min for 3 hours.

[0026] S5: Thawing and oiling: Remove the frozen fish fillets from the mold, lay them flat on the conveyor belt of the fish grilling machine, and brush the surface with soybean oil equal to 2% of the weight of the fish fillets.

[0027] S6: Gradient Temperature Control Baking: Set the heating plate temperature of the fish grill to 140℃. Grill the fish fillets for 5 minutes on one side, then flip and grill the other side for 5 minutes.

[0028] S7: Air dry: Remove the fish fillets and place them on a stainless steel wire rack. Let them air dry naturally at room temperature (25℃, 50% relative humidity) for 15 minutes.

[0029] S8: Mechanical loosening: The dried fish fillets are fed into a loosening processing device. The loosening processing device includes two opposing fixed frames 1 and a first loosening roller 2 and a second loosening roller 3 positioned between the two fixed frames from top to bottom. The two ends of the first and second loosening rollers are respectively mounted on the two fixed frames via bearings. One end of the first loosening roller is fixedly connected to a first gear 4, and the same end of the second loosening roller is fixedly connected to a second gear 5. The first and second gears mesh with each other. The first loosening roller is connected to a drive motor 6, which drives the first loosening roller to rotate and, through gear meshing, drives the second loosening roller to rotate in the opposite direction. One end of the second loosening roller extends to the outside of the second gear and is fixedly connected to a handle 7. Several radial grooves 8 are equidistantly spaced along the axial direction on the surfaces of the two rollers. The depth of the radial grooves is 3 mm, and the spacing is 8 mm. The rotational linear speed of the loosening rollers is 10 m / min. As the two rollers rotate in opposite directions, the fish fillets are subjected to periodic compression and release, tearing the muscle fibers into a fluffy filamentous structure. The fish fillets expand in volume by 30%, and their texture changes from hard to loose.

[0030] S9: High-temperature branding: Heat the branding iron 9 with the raised "Dalian" logo 10 to 380℃. Press it vertically down on the center of the fish fillet, hold the pressure for 5 seconds, and then lift it up. A clear dark brown text mark will appear on the surface of the fish fillet.

[0031] Example 2 Unlike Example 1, in step (4), the freezing temperature is -18°C and the freezing time is 4 hours; in step (6), the baking temperature is 135°C and the baking time on one side is 8 minutes; in step (8), the gap between the stretching rollers is set to 60% of the thickness of the fish fillet; in step (9), the branding temperature is 370°C and the holding time is 10 seconds. Other steps and parameters are the same as in Example 1.

[0032] Example 3 Unlike Example 1, the raw fish was replaced with fresh mullet, which was directly pre-treated without freezing; in step (4), the freezing temperature was -30℃ and the freezing time was 1.5 hours; in step (6), the baking temperature was 145℃ and the baking time on one side was 3 minutes; in step (8), the gap between the stretching rollers was set to 80% of the thickness of the fish fillet; in step (9), the branding temperature was 400℃ and the holding time was 3 seconds. Other steps and parameters were the same as in Example 1.

[0033] Comparative Example 1 (Traditional sectioning process) According to the method of the embodiment in application publication number CN102450693A, cod is directly cut into raw fish slices with a thickness of about 5mm by hand, without compression or freezing for shaping, and directly seasoned and baked in an oven at 250℃ for 15 minutes, without stretching or branding.

[0034] Comparative Example 2 (without freeze-setting step) The only difference from Example 1 is that step (4) freezing and shaping is omitted, and the product is directly brushed with oil and baked after grinding and compression. The remaining steps are exactly the same as in Example 1.

[0035] Comparative Example 3 (without the stretching step) The only difference from Example 1 is that step (8) loosening is omitted. The remaining steps are exactly the same as in Example 1.

[0036] Comparative Example 4 (without compression molding step) The only difference from Example 1 is that step (3) compression molding is omitted, and the ground fish paste is directly frozen and shaped. The remaining steps are exactly the same as in Example 1.

[0037] The following indicators were tested on the roasted fish slices obtained in Examples 1-3 and Comparative Examples 1-4, and the results are shown in Table 1: As can be seen from the data in Table 1: Compared with Comparative Example 1, the process of the present invention significantly improves the integrity rate of the slices, reduces the hardness by nearly half, and significantly improves the nutrient retention rate, indicating that the combination of compression freezing and low-temperature baking effectively improves the shape and nutrition.

[0038] Compared with Example 1, although both had a high integrity rate, Comparative Example 2, which was not frozen and set, showed a significantly increased thickness shrinkage rate during baking, and the edges of the fish fillets exhibited slight wavy deformation. Its crispness score was significantly lower than that of Example 1. This indicates that freezing and setting are crucial for maintaining precise geometry and internal microporous structure.

[0039] Compared with Example 1 and Comparative Example 3, the unstretched fish fillets were significantly harder, resulting in a dry, hard texture that was difficult to chew. This demonstrates that the stretching step is a key method for reducing hardness and achieving a crisp texture, and its synergistic effect with freezing to create pores is far superior to either treatment alone.

[0040] Compared with Example 1 and Comparative Example 4, although the fish fillets that were not compressed were frozen and shaped, the fish meat paste was not compacted, resulting in a large number of air bubbles and a loose structure inside. As a result, the integrity of the fillet shape was significantly reduced after baking, and the hardness was also higher. This shows that compression molding and freezing and shaping need to work together to ensure that the fish fillet body is dense and uniform, providing an ideal basic structure for subsequent baking and fluffing.

[0041] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for processing grilled fish fillets, characterized in that, Includes the following steps: S1: Slicing and deboning: After removing the skin, scales and internal organs of the raw fish, cut the fish meat off both sides of the fish along the spine and remove the fish bones. S2: Grinding and mincing: Grind the fish meat obtained in step S1 into a minced state; S3: Compression molding: The ground fish paste is filled into a molding mold, pressure is applied to compact it and the pressure is maintained to make compressed sashimi; S4: Freezing and shaping: Place the compressed fish fillets in a freezer and freeze at -18℃ to -30℃ for 1-4 hours; S5: Brush with oil: Take out the frozen and shaped fish fillets, lay them flat on the heating platform of the fish grill, and brush vegetable oil on the surface of the fish fillets; S6: Baking: Set the heating platform temperature of the fish grill to 135℃-145℃, grill one side of the fish fillet for 3-8 minutes, flip it over and grill the other side for 3-8 minutes; S7: Air dry: Remove the baked fish fillets and air dry naturally for 10-20 minutes; S8: Loosening: The dried fish fillets are sent into a loosening processing device for loosening. S9: Branding: Heat the branding iron to 370℃-400℃ and press it onto the surface of the fish fillet for 3-10 seconds to form text or pattern markings.

2. The method for processing grilled fish fillets according to claim 1, characterized in that, The compression molding pressure in step S3 is 0.5-2 MPa, and the holding time is 10-30 seconds.

3. The method for processing grilled fish fillets according to claim 1, characterized in that, The cooling rate for freezing in step S4 is 5-10℃ / min.

4. The method for processing grilled fish fillets according to claim 1, characterized in that: The amount of oil brushed in step S5 is 1%-3% of the fish fillet's weight.

5. The method for processing grilled fish fillets according to claim 1, characterized in that: The loosening processing equipment in step S8 includes two fixed frames arranged opposite each other and a first loosening roller and a second loosening roller arranged from top to bottom between the two fixed frames. The two ends of the first loosening roller and the second loosening roller are respectively mounted on the two fixed frames by bearings. One end of the first loosening roller is fixedly connected to a first gear, and the same end of the second loosening roller is fixedly connected to a second gear. The first gear and the second gear mesh with each other. The first stretching roller is connected to the drive motor. The motor drives the first stretching roller to rotate and drives the second stretching roller to rotate in the opposite direction through gear meshing. One end of the second stretching roller extends to the outside of the second gear and is fixedly connected to a handle. Several radial grooves are equidistantly opened on the surface of the two rollers along the axial direction. When the two rollers rotate in opposite directions, the fish fillet is stretched by pressure when it passes through the gap between the two rollers.

6. The method for processing grilled fish fillets according to claim 5, characterized in that: The radial grooves have a depth of 2-5 mm and a spacing of 5-10 mm, and the linear speed of the stretching roller is 5-20 m / min.

7. The method for processing grilled fish fillets according to claim 1, characterized in that, In step S6, a seasoning liquid is sprayed onto the surface of the fish fillets before or during baking. The seasoning liquid contains 5%-15% white sugar and 2%-5% salt.

8. A type of grilled fish fillet, characterized in that, The roasted fish fillet, processed by any one of claims 1-7, has a regular geometric shape, a carbonized brand mark on the surface, and a loose and porous fibrous structure inside.

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