Processing method and system of minced fillet product added with salted duck egg white

Abstract

The invention relates to a processing method and system of a surimi product added with salted duck egg white. The method comprises the following steps: separating, rinsing and dehydrating fish meat to obtain a surimi base material; the preparation method comprises the following steps: putting salted duck egg white into a pre-treatment unit, ventilating and whipping through jet circulation in a stirring state, and controlling the temperature to be 4-10 DEG C, so as to prepare micro-puffed slurry containing uniform micro-bubbles; after a minced fillet base material is subjected to empty grinding and salt grinding, adding the slurry and auxiliary materials at low temperature, and mixing to obtain mixed minced fillet; and after forming, gelatinizing and curing to obtain the minced fillet product. The system comprises a surimi preparation unit, a pretreatment unit, a mixing and chopping unit and a gelation and curing unit. According to the invention, the salted duck egg white is beaten into micro-puffed slurry in advance and then mixed with the surimi, so that the problem that the taste is slightly hard due to direct addition is solved, large-proportion addition of the salted duck egg white can be realized, the cost is reduced, the prepared surimi product is moderate in gel strength, good in whiteness and fine and smooth in taste, and the sensory quality of the surimi product is basically consistent with that of a traditional pure surimi product.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a method and system for processing surimi products with added salted duck egg white. Background Technology

[0002] Surimi products (such as fish shumai, fish balls, fish cakes, and fish tofu) are popular among consumers due to their high nutritional value and delicious taste. However, the high production cost of traditional pure surimi products limits their market penetration. To meet the needs of different consumer groups, developing new, low-cost, and nutritious surimi products has become an industry trend.

[0003] Salted duck egg white is a major byproduct of salted egg yolk processing, with large yields and low prices. Studies have shown that adding an appropriate amount of salted duck egg white to surimi can not only inhibit the activity of endogenous heat-activated proteases in fish and improve the gel properties of surimi, but also effectively reduce raw material costs and enhance the product's market competitiveness. Therefore, the application of salted duck egg white in surimi products has significant economic value and promising prospects for promotion.

[0004] Currently, some companies are experimenting with adding salted duck egg whites directly to surimi production. However, because surimi processing requires rapid chopping at low temperatures, the beating speed is relatively slow and the time is short. Directly added salted duck egg whites cannot be fully whipped, resulting in uneven distribution within the surimi and difficulty in forming a stable bubble structure. This ultimately leads to a hard texture and coarse consistency in the surimi product. To avoid a decline in product quality, manufacturers must strictly control the amount of salted duck egg whites added, typically adding only small amounts, making it difficult to achieve significant cost reduction and efficiency gains.

[0005] To address the aforementioned issues, current technologies lack a processing method or dedicated system that can simultaneously achieve a high proportion of salted duck egg white to reduce production costs while maintaining the gel strength, texture, and sensory quality of surimi products. Therefore, developing a processing technology and supporting system capable of effectively pre-treating salted duck egg white to ensure its uniform dispersion and formation of a stable microporous structure in surimi is a pressing problem that needs to be solved. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the first objective of this invention is to provide a method for processing surimi products with added salted duck egg white. The method involves pre-aerating and whipping the salted duck egg white to prepare a micro-expanded slurry containing uniformly distributed micro-bubbles, which is then mixed with surimi. This allows for the addition of salted duck egg white in a large proportion, resulting in surimi products with moderate gel strength, a delicate texture, and sensory quality that is essentially consistent with traditional pure surimi products.

[0007] The second objective of this invention is to provide a surimi product processing system with added salted duck egg white, for implementing the above-mentioned processing method, including a surimi preparation unit, a salted duck egg white pretreatment unit, a mixing and chopping unit, and a gelling and maturation unit, wherein the pretreatment unit adopts a jet circulation ventilation whipping device, which can quickly whip the salted duck egg white into a micro-expanded slurry at low temperature.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for processing surimi products with added salted duck egg white includes the following steps: Fish meat is processed by harvesting, rinsing, and dehydrating to obtain fish paste base material; Salted duck egg whites are placed in a pretreatment unit and aerated and whipped under stirring conditions using jet circulation. The whipping temperature is controlled at 4-10℃ to prepare a micro-expanded salted duck egg white slurry containing uniformly distributed micro-bubbles. After the fish paste base is pounded in the air and then salted, the micro-puffed salted duck egg white slurry and auxiliary materials are added under low temperature conditions and mixed evenly to obtain mixed fish paste. After the mixed fish paste is shaped, it is subjected to gelation treatment and maturation treatment in sequence to obtain fish paste products.

[0009] Preferably, the whipping temperature of salted duck egg whites is 5℃.

[0010] According to one example, during the aeration and stirring process, the stirring is first carried out at a low speed of 60-120 rpm for 2-3 minutes, and then the stirring speed is increased to 300-500 rpm. At the same time, compressed air with a pressure of 0.03-0.05 MPa is circulated through the ejector and the aeration is continuously circulated for 6-10 minutes.

[0011] According to one example, the rinsing is a three-stage rinsing process, which involves rinsing with clean water, brine with a mass concentration of 0.3%, and clean water in sequence; the moisture content of the fish paste base after dehydration is 80-85%.

[0012] According to one example, the empty grinding time is 4-5 minutes; the salt grinding time is 5-8 minutes, and the amount of salt added is 2-2.5% of the mass of the surimi base.

[0013] According to one example, the low-temperature condition is a temperature controlled at 4-10°C; the auxiliary materials include starch, sugar and compound phosphate, which are added in amounts of 5-10%, 1-4% and 0.1-0.35% of the mass of the surimi base material, respectively, and water is added at 8-12% of the mass of the surimi base material.

[0014] According to one example, the amount of micro-puffed salted duck egg white slurry added is 15%-35% of the mass of the fish paste base.

[0015] Preferably, the amount of micro-puffed salted duck egg white slurry added is 20% of the mass of the fish paste base.

[0016] According to one example, the gelation treatment is to stand at 50°C to 55°C for 30-50 minutes; the aging treatment is to immerse in water at 90-95°C for 20-25 minutes.

[0017] A surimi product processing system for adding salted duck egg white to implement the processing method includes: The surimi preparation unit includes a meat extraction device, a rinsing device, and a dehydration device, used to process fish meat into surimi base material; A pretreatment unit is used to aerate and whip salted duck egg whites, the pretreatment unit comprising: The tank has an inlet at the top and an outlet at the bottom, and a liquid outlet and a liquid inlet are formed on the side of the tank. A stirring assembly includes a rotating shaft and at least one blade disposed on the rotating shaft, the upper end of the rotating shaft being rotatably connected to the top of the tank. A jet assembly includes a pump body and an ejector arranged in series. The input end of the pump body is connected to the liquid outlet of the tank through a first pipeline, and the output end of the ejector is connected to the liquid inlet of the tank through a second pipeline. The ejector also has an air inlet. A temperature control assembly includes a jacket fitted onto the outer wall of the tank body, the jacket defining a medium cavity between the jacket and the tank body, and a medium inlet and a medium outlet communicating with the medium cavity respectively formed on the jacket. A mixing and chopping unit is connected to the fish paste preparation unit and the pretreatment unit, respectively. It is used to mix the fish paste base material with the micro-expanded salted duck egg white slurry and auxiliary materials after air pounding and salt pounding to obtain mixed fish paste. A gelling and maturation unit is connected to the mixing and chopping unit. The gelling and maturation unit is used to perform gelling and maturation treatments on the mixed fish paste after it is shaped, so as to obtain fish paste products.

[0018] According to one example, the outlet end of the second pipe extends horizontally toward the central axis of the tank and then bends upward, the outlet end of the second pipe is located below the blade, and the outlet end of the second pipe has a plurality of air outlet holes formed thereon.

[0019] According to one example, the stirring assembly further includes a drive motor fixed to the top of the tank, and the output shaft of the drive motor is drively connected to the upper end of the rotating shaft.

[0020] The present invention has the following advantages: This invention pre-treats salted duck egg whites with jet-circulating aeration and whipping at a low temperature of 4-10℃, preparing them into a micro-expanded slurry containing uniformly distributed microbubbles. This allows the pre-whipped salted duck egg whites to be added to fish paste, avoiding the problems of insufficient whipping due to slow chopping speed and short time in traditional direct addition methods. The pre-treated micro-expanded salted duck egg white slurry is evenly distributed in the fish paste, with a stable bubble structure, resulting in a final fish ball gel strength of 2392 g·cm, which is essentially equivalent to pure fish paste fish balls and significantly superior to fish balls made by directly adding untreated salted duck egg whites.

[0021] This invention enables the high-proportion addition of salted duck egg white, with an addition amount reaching 15-35% of the fish paste base material. This effectively reduces the raw material cost of fish paste products and provides a new way to utilize salted duck egg white, a byproduct of salted egg yolk processing, thus reducing environmental pollution and resource waste. Whiteness testing showed that the fish balls prepared by this invention had a significantly higher whiteness value than those made by directly adding untreated salted duck egg white. Folding tests indicated that the fish balls prepared by this invention did not crack after being folded three times, exhibiting toughness comparable to pure fish paste fish balls.

[0022] The fish balls prepared by this invention have excellent sensory quality. They are white in color, smooth in surface, dense in cross-section without large air pores, elastic, refreshing and non-sticky, have a fishy aroma and virtually no fishy smell from salted egg white, and a normal saltiness. Their sensory quality is basically consistent with traditional pure fish paste fish balls. After 15 days of refrigerated storage, all quality indicators remain stable, demonstrating good shelf-life stability. Furthermore, the processing system provided by this invention has a reasonable structure and is suitable for the production of various fish paste products such as fish paste shumai, fish balls, fish cakes, and fish tofu. It can also be applied to the pretreatment of other egg whites such as salted egg whites and salted goose egg whites. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the method for processing surimi products with added salted duck egg white according to the present invention.

[0024] Figure 2 This is a process flow diagram of the preparation steps of the surimi base material of the present invention.

[0025] Figure 3 This is a process flow diagram of the salted duck egg white pretreatment steps of the present invention.

[0026] Figure 4 This is a process flow diagram of the mixing, gelation and maturation steps of the present invention.

[0027] Figure 5 This is a schematic diagram of the surimi product processing system of the present invention.

[0028] Figure 6 This is a schematic diagram of the preprocessing unit of the present invention.

[0029] Figure 7 This is a schematic diagram of the jet assembly of the present invention.

[0030] Figure 8 This is a cross-sectional photo of the fish balls prepared in Example 1 of the present invention after being refrigerated for 1 day.

[0031] Figure 9 This is a cross-sectional photo of the fish balls prepared in Example 2 of the present invention after being refrigerated for 1 day.

[0032] Figure 10 This is a cross-sectional photo of the fish balls prepared in Example 3 of the present invention after being refrigerated for 1 day.

[0033] Figure 11 This is a cross-sectional photograph of the fish balls prepared in Comparative Example 1 of this invention after being refrigerated for 1 day.

[0034] Figure 12 This is a cross-sectional photograph of the fish balls prepared in Comparative Example 2 of this invention after being refrigerated for 1 day.

[0035] Figure 13 This is a cross-sectional photo of the fish balls prepared in Example 1 of this invention after being refrigerated for 15 days.

[0036] Figure 14 This is a cross-sectional photograph of the fish balls prepared in Comparative Example 1 of this invention after being refrigerated for 15 days.

[0037] In this system, A is the pretreatment unit, 1 is the tank, 101 is the feed inlet, 102 is the discharge outlet, 103 is the liquid outlet, 104 is the liquid inlet, 2 is the stirring assembly, 201 is the rotating shaft, 202 is the impeller, 203 is the drive motor, 3 is the jet assembly, 301 is the pump body, 302 is the jet injector, 302a is the air inlet, 303 is the first pipeline, 304 is the second pipeline, 304a is the air outlet, 4 is the temperature control assembly, 401 is the jacket, 401a is the medium inlet, 401b is the medium outlet, 402 is the medium chamber, 403 is the temperature control element, B is the surimi preparation unit, C is the mixing and chopping unit, and D is the gelation and ripening unit. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field. Test methods in the following embodiments that do not specify specific experimental conditions are generally performed under conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the present invention are all commercially available. Example

[0039] Reference Figure 1-4 The present application discloses a method for processing surimi products with added salted duck egg white, the specific steps of which are as follows: Preparation of fish paste base: Select frozen silver carp (260 kg), thaw below 10℃, extract meat with a meat extractor, rinse three times in sequence with clean water, 0.3% brine, and clean water, centrifuge to dehydrate to a moisture content of 85%, and obtain 100 kg of fish paste base.

[0040] Salted duck egg white pretreatment: Take 20kg of salted duck egg white refrigerated at 5℃ and place it in pretreatment unit A. First, adjust the stirring speed of the stirring paddle to 60rpm and stir at low speed for 3 minutes. Then, increase the stirring speed to 500rpm and simultaneously circulate compressed air at a pressure of 0.05MPa through the ejector 302. Continuously circulate and beat for 10 minutes to prepare a micro-expanded salted duck egg white slurry containing uniformly distributed microbubbles.

[0041] Mixing and chopping: Pour 100kg of fish paste base into a chopping pot and pound it empty for 5 minutes. Add 2.5kg of salt and continue pounding for 8 minutes. Then, under low temperature conditions of 4-10℃, add 20kg of the prepared micro-puffed salted duck egg white slurry, along with 5kg of starch, 3kg of white sugar, 0.3kg of compound phosphate, and 10kg of water. Continue stirring for 8 minutes until the mixture is evenly mixed to obtain the mixed fish paste.

[0042] Gelation and Curing: The mixed fish paste is formed into fish balls using a molding machine. The formed fish balls are placed in a gelation tunnel and first allowed to stand at 55°C for 40 minutes for gelation treatment. Then, they are transferred to a curing device and soaked in water at 93°C for 20 minutes for curing treatment.

[0043] Cooling and Packaging: The cooked fish balls are cooled to room temperature by spraying them with cold water, drained, and then packaged using a vacuum packaging machine and stored at 4°C. Example

[0044] Preparation of fish paste base: Select frozen silver carp (260 kg), thaw below 10℃, extract meat with a meat extractor, rinse three times in sequence with clean water, 0.3% brine, and clean water, centrifuge to dehydrate to a moisture content of 85%, and obtain 100 kg of fish paste base.

[0045] Salted duck egg white pretreatment: Take 20kg of salted duck egg white refrigerated at 5℃ and place it in pretreatment unit A. First, adjust the stirring speed of the stirring paddle to 120rpm and stir at low speed for 3 minutes. Then, increase the stirring speed to 300rpm and simultaneously circulate compressed air at a pressure of 0.03MPa through the ejector 302. Continue to circulate and beat for 6 minutes to prepare a micro-expanded salted duck egg white slurry containing uniformly distributed microbubbles.

[0046] Mixing and chopping: Pour 100kg of fish paste base into a chopping pot and pound it empty for 4 minutes. Add 2.5kg of salt and continue pounding for 5 minutes. Then, under low temperature conditions of 4-10℃, add 20kg of the prepared micro-puffed salted duck egg white slurry, along with 5kg of starch, 3kg of white sugar, 0.3kg of compound phosphate, and 10kg of water. Continue stirring for 8 minutes until the mixture is evenly mixed to obtain the mixed fish paste.

[0047] Gelation and Curing: The mixed fish paste is formed into fish balls using a molding machine. The formed fish balls are placed in a gelation tunnel and first allowed to stand at 50°C for 40 minutes for gelation treatment. Then, they are transferred to a curing device and immersed in 95°C water for 20 minutes for curing treatment.

[0048] Cooling and Packaging: The cooked fish balls are cooled to room temperature by spraying them with cold water, drained, and then packaged using a vacuum packaging machine and stored at 4°C. Example

[0049] Preparation of fish paste base: Select frozen silver carp (235 kg), thaw below 10℃, extract meat with a meat extractor, rinse three times in sequence with clean water, 0.3% brine, and clean water, centrifuge to dehydrate to a moisture content of 85%, and obtain 90 kg of fish paste base.

[0050] Salted duck egg white pretreatment: Take 30kg of salted duck egg white refrigerated at 5℃ and place it in pretreatment unit A. First, adjust the stirring speed of the stirring paddle to 60rpm and stir at low speed for 3 minutes. Then, increase the stirring speed to 500rpm and simultaneously circulate compressed air at a pressure of 0.05MPa through the ejector 302. Continue to circulate and beat for 8 minutes to prepare a micro-expanded salted duck egg white slurry containing uniformly distributed microbubbles.

[0051] Mixing and chopping: Pour 90kg of fish paste base into a chopping pot and pound it empty for 4 minutes. Add 2.0kg of salt and continue pounding for 6 minutes, keeping the temperature at a low temperature of 4-10℃. Then add 30kg of the prepared micro-puffed salted duck egg white slurry, along with 5kg of starch, 3kg of white sugar, 0.3kg of compound phosphate, and 10kg of water. Continue stirring for 8 minutes until the mixture is evenly mixed to obtain the mixed fish paste.

[0052] Gelation and Curing: The mixed fish paste is formed into fish balls using a molding machine. The formed fish balls are placed in a gelation tunnel and first allowed to stand at 55°C for 40 minutes for gelation treatment. Then, they are transferred to a curing device and soaked in 90°C water for 20 minutes for curing treatment.

[0053] Cooling and Packaging: The cooked fish balls are cooled to room temperature by spraying them with cold water, drained, and then packaged using a vacuum packaging machine and stored at 4°C.

[0054] Comparative Example 1 The same fish paste base and auxiliary materials as in Example 1 (5 kg starch, 3 kg white sugar, 0.3 kg compound phosphate, 10 kg water) were used, but instead of adding micro-puffed salted duck egg white slurry, 20 kg of fish paste base with the same weight as salted duck egg white in Example 1 was directly added. Fish balls were prepared according to the same empty pounding, salt pounding, mixing and chopping, gelling and cooking process as in Example 1, and stored at 4°C.

[0055] Comparative Example 2 Fish balls were prepared using the same surimi base and auxiliary materials as in Example 1 (5 kg starch, 3 kg white sugar, 0.3 kg compound phosphate, and 10 kg water), but an equal weight (20 kg) of untreated salted duck egg white was added directly to replace the micro-puffed salted duck egg white slurry in Example 1. The fish balls were prepared using the same empty pounding, salt pounding, mixing and chopping, gelling and cooking process as in Example 1, and stored at 4°C.

[0056] Example 1 of effect verification Fish balls prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 (refrigerated at 4°C for 1 day), and fish balls prepared in Examples 1 and Comparative Example 1 (refrigerated for 15 days) were selected. A 3mm thick slice was cut from the middle of each fish ball, and the L value (brightness), a value (red-green value), and b value (yellow-blue value) were measured using a WSD-3 fully automatic whiteness meter. Each sample was measured three times, and the average value was taken. The Hunter whiteness (Wh) was calculated using the following formula: Calculation formula:

[0057] The measurement results are shown in Table 1.

[0058] Table 1. Results of whiteness test for fish balls.

[0059] sample L a b Wh Example 1: Refrigerated for 1 day 77.76 -0.26 6.52 76.82 Example 2: Refrigerated for 1 day 76.65 -0.31 7.5 75.47 Example 3: Refrigerated for 1 day 77.37 -1.42 7.33 76.17 Comparison 1 (Refrigerated for 1 day) 75.65 -0.46 8.72 74.13 Comparison 2 (refrigerated for 1 day) 69.84 -1.33 7.69 68.85 Example 1: Refrigerated for 15 days 75.65 1.47 8.54 74.15 Comparison Example 1 (Refrigerated for 15 days) 74.93 1.13 9.86 73.04 As shown in Table 1, after refrigeration for one day, the whiteness values ​​(Wh = 75.47-76.82) of the fish balls in Examples 1-3 with added pretreated salted duck egg white were all higher than those in Comparative Example 1 (Wh = 74.13) without added salted duck egg white, and significantly higher than those in Comparative Example 2 (Wh = 68.85) with directly added untreated salted duck egg white. This indicates that the micro-puffed salted duck egg white slurry prepared by the method of the present invention can effectively improve the whiteness of the fish balls. After refrigeration for 15 days, the whiteness value (Wh = 74.15) of the fish balls in Example 1 was still higher than that in Comparative Example 1 (Wh = 73.04), and both only showed slight yellowing, indicating that the fish balls prepared by the method of the present invention have good whiteness stability during refrigerated storage.

[0060] Example 2 of effect verification Fish balls prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2, which were refrigerated at 4℃ for 1 day, and fish balls prepared in Examples 1 and Comparative Example 1, which were refrigerated for 15 days, were selected. A 3mm thick slice was cut from the middle of each fish ball and subjected to a folding test (folded 2 or 3 times). After holding the slice for 30 seconds, the presence and degree of cracking were observed. Nine fish ball slices were taken from each sample for testing, and the results are shown in Table 2.

[0061] Table 2. Results of the fish ball folding test.

[0062] sample Folding test results Test Results Example 1: Refrigerated for 1 day Fold in half 3 times No cracks were found in any of the 9 samples. Example 2: Refrigerated for 1 day Fold in half 3 times No cracks were found in any of the 9 samples. Example 3: Refrigerated for 1 day Fold in half twice Two of the nine samples were cracked. Comparison 1 (Refrigerated for 1 day) Fold in half 3 times No cracks were found in any of the 9 samples. Comparison 2 (refrigerated for 1 day) Fold in half twice Two of the nine samples were cracked. Example 1: Refrigerated for 15 days Fold in half 3 times No cracks were found in any of the 9 samples. Comparison 1 (refrigerated for 15 days) Fold in half 3 times No cracks were found in any of the 9 samples. As shown in Table 2, after refrigeration for one day, the fish ball slices of Examples 1 and 2 did not crack after being folded three times, exhibiting toughness comparable to Comparative Example 1 (pure fish paste). However, two samples of the fish ball slices of Example 3 (with salted duck egg white added at approximately 33% of the fish paste weight) and Comparative Example 2 (with untreated salted duck egg white added directly) cracked after being folded twice, indicating that excessive salted duck egg white addition or direct addition without pretreatment can lead to decreased toughness and brittleness of the fish balls. After refrigeration for 15 days, the fish ball slices of Examples 1 and 1 still did not crack after being folded three times, demonstrating that the fish balls prepared by the method of this invention have good toughness stability during refrigerated storage.

[0063] Example 3 of effect verification Fish balls prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2, refrigerated at 4℃ for 1 day, and fish balls prepared in Examples 1 and Comparative Example 1, refrigerated for 15 days, were selected. After being placed at room temperature, the breaking strength (g) and indentation depth (mm) of the fish paste gel were measured using a QTS-25 texture analyzer. The product of the two was the gel strength (g·cm). The measurement conditions were: TA41 cylindrical probe, detection speed 30 mm / min, and pressure distance 25 mm. Each sample was measured 3 times, and the average value was taken. The results are shown in Table 3.

[0064] Table 3. Results of fish ball gel strength test.

[0065] sample gel strength (g·cm) Example 1: Refrigerated for 1 day 2392 Example 2: Refrigerated for 1 day 2270 Example 3: Refrigerated for 1 day 2237 Comparison 1 (Refrigerated for 1 day) 2478 Comparison 2 (refrigerated for 1 day) 1931 Example 1: Refrigerated for 15 days 2275 Comparison 1 (refrigerated for 15 days) 2328 As shown in Table 3, after refrigeration for 1 day, the gel strength of the fish balls in Example 1 was 2392 g·cm, which was basically equivalent to that of Comparative Example 1 (pure fish paste, 2478 g·cm). The gel strengths of Examples 2 and 3 were 2270 g·cm and 2237 g·cm, respectively, slightly lower than Comparative Example 1 but still at a high level. The gel strength of Comparative Example 2 (directly added untreated salted duck egg white) was only 1931 g·cm, significantly lower than other samples, indicating that untreated salted duck egg white significantly reduces the gel strength of the fish balls. After refrigeration for 15 days, the gel strength of the fish balls in Example 1 was 2275 g·cm, and that of Comparative Example 1 was 2328 g·cm. The difference between the two was not significant, and the decrease was smaller compared to the corresponding samples refrigerated for 1 day, indicating that the fish balls prepared by the method of this invention have good gel strength stability during refrigerated storage. In summary, the method of this invention, which pre-whips salted duck egg white into a slightly puffed slurry before mixing it with fish paste, can effectively maintain the gel strength of the fish balls, making them essentially the same as pure fish paste fish balls. This is significantly better than the method of directly adding untreated salted duck egg white.

[0066] Example 4 of effect verification Fish balls prepared by Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 that were refrigerated at 4°C for 1 day, and fish balls prepared by Examples 1 and Comparative Example 1 that were refrigerated for 15 days were selected. After cooking, each sample was divided into 10 equal portions for sensory evaluation.

[0067] Ten evaluators (5 males and 5 females) with relevant knowledge and experience in this field were selected to conduct sensory descriptions of the fish balls in four aspects: appearance, texture, smell, and taste. The results are shown in Table 4.

[0068] Table 4. Sensory evaluation results.

[0069] sample Sensory characteristics description Example 1: Refrigerated for 1 day It is white in color, smooth in surface, and has a dense cross-sectional structure without large air pores; it has good elasticity, is refreshing and not sticky, and has a slightly grainy texture; it has a fishy aroma, with virtually no fishy smell from salted egg white, and a normal saltiness. Example 2: Refrigerated for 1 day It is white in color, has a dense cross-sectional structure with no large air pores, and a smooth surface; it has good elasticity, is refreshing and not sticky, and has a slightly grainy texture; it has a fishy aroma, with virtually no fishy smell from salted egg white, and a normal saltiness. Example 3: Refrigerated for 1 day The color is white with a grayish tinge. The cross-section is relatively dense with no large air pores and the surface is relatively smooth. It has good elasticity, is refreshing and not sticky, and has a grainy texture. It has a fishy aroma, a salted egg white fishy smell, and is slightly salty. Comparison 1 (Refrigerated for 1 day) It is off-white in color, with a relatively dense cross-section structure, no large air pores, and a relatively smooth surface; it has good elasticity, is refreshing and not sticky, and has a grainy texture; it has a fishy aroma, no fishy smell of salted egg white, and a normal saltiness. Comparison 2 (refrigerated for 1 day) The color is grayish-white, the cross-section is relatively dense with large air pores, and the surface is slightly rough; it has poor elasticity, is refreshing and not sticky, and has an uneven texture; it has a fishy aroma, a salted egg white fishy smell, and a normal saltiness. Example 1: Refrigerated for 15 days It is white in color, smooth in surface, and has a dense cross-sectional structure without large air pores; it has good elasticity, is refreshing and not sticky, and has a slightly grainy texture; it has a fishy aroma, with virtually no fishy smell from salted egg white, and a normal saltiness. Comparison Example 1 (Refrigerated for 15 days) The color is white with a slight yellow tinge. The cross-section is relatively dense with no large air pores and the surface is relatively smooth. It has good elasticity, is refreshing and not sticky, and has a grainy texture. It has a fishy aroma, no fishy smell of salted egg white, and a normal saltiness. As shown in Table 4, after refrigeration for one day, the fish balls of Examples 1 and 2 were similar to Comparative Example 1 (pure fish paste) in appearance, elasticity, texture, and flavor, with no obvious salted egg white fishy smell and normal saltiness. The fish balls of Example 3 were slightly grayish in color, had a slight salted egg white fishy smell, and were slightly salty, indicating that the excessive amount of salted duck egg white added (approximately 33% of the weight of the fish paste) would have a certain impact on sensory quality. The fish balls of Comparative Example 2 had a rough surface, large air pores, poor elasticity, and a salted egg white fishy smell, indicating that directly adding untreated salted duck egg white would significantly reduce the sensory quality of the fish balls. After refrigeration for 15 days, the sensory quality of the fish balls of Examples 1 and 1 was basically the same as that after refrigeration for one day, indicating that the fish balls prepared by the method of the present invention have good sensory stability during refrigerated storage. In summary, by using the method of this invention to pre-whip salted duck egg whites into a slightly puffed slurry and add an appropriate amount, the resulting fish balls are basically consistent with pure fish paste fish balls in terms of appearance, texture, smell, and taste. This effectively solves the problems of hard texture and obvious fishy smell caused by directly adding salted duck egg whites.

[0070] Example 5 of effect verification Fish balls prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2, refrigerated at 4°C for 1 day, and fish balls prepared in Examples 1 and Comparative Example 1, refrigerated for 15 days, were selected. A 3mm thick slice was cut from the middle of each fish ball and placed in a container for photographic observation. The cross-sectional photographs of the fish balls from Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2, refrigerated for 1 day, are shown below. Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 The cross-sectional photos of the fish balls from Example 1 and Comparative Example 1, which were refrigerated for 15 days, are shown below. Figure 13 and Figure 14 .from Figure 8-14 As can be seen, the fish balls in Examples 1 and 2 have a dense cross-sectional structure with small and uniform pores, similar to the cross-sectional shape of Comparative Example 1 (pure fish paste); the fish balls in Example 3 have a relatively dense cross-sectional structure, but with a slightly granular feel; the fish balls in Comparative Example 2 have obvious large pores and an uneven structure. After refrigeration for 15 days, the cross-sectional shape of the fish balls in Examples 1 and Comparative Example 1 is basically the same as that after refrigeration for 1 day, with no significant changes.

[0071] Reference Figure 5This application also provides a surimi processing system for adding salted duck egg white to implement the processing method. The system generally includes a surimi preparation unit B, a pretreatment unit A, a mixing and chopping unit, and a gelling and maturation unit D. The surimi preparation unit B processes raw fish meat into surimi base material after extraction, rinsing, and dehydration. The pretreatment unit A is used to perform aeration and whipping treatment on the salted duck egg white. The salted duck egg white is pre-stirred at low speed by the stirring component 2 in the tank 1, and then compressed air is circulated through the jet component 3 for high-speed aeration and whipping. Simultaneously, the whipping temperature is controlled at 4-10℃ by the temperature control component 4, resulting in a micro-expanded salted duck egg white slurry containing uniformly distributed microbubbles. The mixing and chopping unit is connected to both the surimi preparation unit B and the pretreatment unit A, and is used to air-pound and salt-pound the surimi base material, then mix it evenly with the micro-expanded salted duck egg white slurry and auxiliary materials under low-temperature conditions to obtain mixed surimi. The gelation and maturation unit D is connected to the mixing and chopping unit. The gelation and maturation unit D is used to perform gelation and maturation treatments on the mixed fish paste after it is shaped, so as to obtain fish paste products.

[0072] The fish paste preparation unit B mainly includes a meat extraction device, a rinsing device, and a dehydration device connected in sequence. The meat extraction device is used to separate the fish meat from the bones and skin, and can be a roller meat extractor, a belt meat extractor, or a platen meat extractor. For example, a roller meat extractor uses a pressing mechanism to press the fish meat into a porous roller, and the fish meat is sent out by a screw conveyor inside the roller, while the bones are scraped off by a scraper.

[0073] The rinsing unit is used to remove water-soluble proteins, fats, and blood from minced fish to improve the elasticity and whiteness of the surimi products. The rinsing unit can be a vertical rinsing tank equipped with a blade agitator, using an intermittent operation method to rinse the fish meat multiple times. In actual production lines, the rinsing unit typically consists of multiple rinsing machines and rotary screens, for example, using a first and second rinsing machine for two rinsing processes to ensure thorough removal of fish oil and blood.

[0074] Dehydration devices are used to remove excess water from fish meat after rinsing. Centrifugal dehydrators or press dehydrators can be used. Centrifugal dehydrators use centrifugal force to separate water from the fish meat, while press dehydrators use pressure generated by a variable-pitch screw to squeeze water out of the fish meat through a sieve. In addition, there are screw extrusion dehydrators, which consist of a fish paste inlet, a dehydration cylinder, a dehydrator main shaft, and a turbine. The fish meat rotates inside the cylinder, and water is discharged through numerous small holes on the outer wall of the cylinder.

[0075] Continue to refer to Figure 6 and Figure 7The pretreatment unit A mainly includes a vertically arranged tank 1, a stirring assembly 2, a jetting assembly 3, and a temperature control assembly 4. The tank 1 holds the salted duck egg whites to be processed. It has an inlet 101 at the top for receiving the salted duck egg whites and an outlet 102 at the bottom for discharging the micro-expanded salted duck egg white slurry after aeration and whipping. The sides of the tank 1 have liquid outlets 103 and liquid inlets 104, which connect to the jetting assembly 3 to form a circulation path for the salted duck egg whites. The bottom of the tank 1 is equipped with multiple support legs, raising the bottom of the tank 1 a certain distance from the ground to facilitate connection between the outlet 102 and downstream units. In addition, the upper part of the tank 1 is equipped with a spare port for installing temperature sensors, pressure gauges, or for use as a cleaning port.

[0076] A stirring assembly 2 is installed inside the tank 1 and is used to mechanically stir the salted duck egg whites to assist in whipping. The stirring assembly 2 includes a rotating shaft 201 and at least one impeller 202 fixedly mounted on the rotating shaft 201. The upper end of the rotating shaft 201 is rotatably connected to a shaft hole formed in the top of the tank 1. The stirring assembly 2 also includes a drive motor 203, which is fixedly mounted on the top of the tank 1, and the output shaft of the drive motor 203 is drivenly connected to the upper end of the rotating shaft 201 to drive the rotating shaft 201 to rotate.

[0077] The number and arrangement of the blades 202 can be adjusted according to the whipping requirements, such as two, three, four, etc. In this embodiment, there are four blades 202, which are evenly distributed circumferentially at the same height of the rotating shaft 201 to form a blade group. Each blade 202 is twisted at a certain angle relative to the radial plane of the rotating shaft 201, and the twisting direction of the four blades 202 is the same, so as to generate axial thrust during rotation and promote the up-and-down circulation of the material in the tank 1. The twisting angle of the blades 202 can be the same, or it can be set to different angles according to the fluid dynamics requirements. In addition, two blade groups arranged vertically can be configured on the rotating shaft 201 to form a more complex flow field in the salted duck egg white in the tank 1 and improve the uniformity of bubble dispersion.

[0078] Continue to refer to Figure 7 The jet assembly 3 includes a pump body 301 and an ejector 302 arranged in series, used to achieve circulating aeration and whipping of salted duck egg whites. The input end of the pump body 301 is connected to the liquid outlet 103 of the tank 1 through a first pipe 303, and the output end of the ejector 302 is connected to the liquid inlet 104 of the tank 1 through a second pipe 304. The ejector 302 also has an air inlet 302a for connecting to a compressed air source.

[0079] In one embodiment, the ejector 302 is internally arranged with a nozzle, an intake chamber, a mixing throat, and a diffuser in sequence along the fluid flow direction. The pump 301 extracts the salted duck egg white from the tank 1 and delivers it to the nozzle of the ejector 302 via the first pipeline 303. The cross-sectional area of ​​the nozzle gradually shrinks, converting the pressure energy of the liquid into kinetic energy, forming a high-speed jet. When the high-speed flowing liquid passes through the intake chamber, a negative pressure zone is formed around the nozzle outlet according to Bernoulli's principle, thereby drawing in external air through the air inlet 302a. The drawn-in air and the high-speed liquid flow collide and shear violently in the mixing throat, breaking into microbubbles and forming a gas-liquid mixture. The gas-liquid mixture then enters the diffuser, where the cross-sectional area gradually expands, the flow velocity decreases, and the pressure rises, promoting further dispersion and stabilization of the bubbles. Finally, it returns to the tank 1 via the second pipeline 304. This cycle repeats, resulting in a large number of microbubbles evenly distributed in the salted duck egg white, forming a micro-expansion state.

[0080] The outlet end of the second pipe 304 extends into the interior of the tank 1. After extending horizontally towards the central axis of the tank 1, the outlet end of the second pipe 304 bends upwards, positioning itself below the impeller 202. This arrangement allows the gas-liquid mixture returning to the tank 1 to be directly sprayed onto the area of ​​the stirring impeller 202. The shearing force generated by the rotation of the impeller 202 further breaks up any large bubbles that may be merging, while simultaneously promoting uniform bubble dispersion within the tank 1. Furthermore, the outlet end of the second pipe 304 has multiple air outlets 304a, causing the gas-liquid mixture to be ejected in multiple fine streams, avoiding concentrated spraying caused by a single large orifice and improving the uniformity of bubble distribution.

[0081] Reference Figure 6 and Figure 7 The temperature control component 4 includes a jacket 401 fitted onto the outer wall of the tank 1. A sealed medium cavity 402 is defined between the jacket 401 and the tank 1 to contain a circulating temperature-controlled medium. The jacket 401 has a medium inlet 401a and a medium outlet 401b communicating with the medium cavity 402. By introducing a circulating cooling medium into the medium cavity 402, the temperature of the salted duck egg whites inside the tank can be maintained between 4-10℃, ensuring effective whipping while inhibiting microbial growth. The cooling medium can be chilled water, ethylene glycol solution, etc.

[0082] The jacket 401 covers the side and bottom walls of the tank 1, forming a three-dimensional enclosure. The medium inlet 401a is located at the upper part of the jacket 401, and the medium outlet 401b is located at the bottom of the jacket 401. This arrangement allows the temperature-controlled medium to flow from top to bottom, filling the entire medium cavity 402 before being discharged from the bottom. The discharge port 102 of the tank 1 extends through the bottom of the jacket 401 to the outside, and a sealing element, such as a sealing ring or welded seal, is provided at the penetration point to prevent the temperature-controlled medium in the medium cavity 402 from leaking along the gap between the discharge port 102 and the jacket 401. Similarly, the first pipeline 303 and the second pipeline 304 respectively penetrate the side wall of the jacket 401 and connect to the liquid outlet 103 and the liquid inlet 104 of the tank 1, and corresponding sealing structures are also provided at the penetration points.

[0083] A temperature control element 403 may also be configured within the medium chamber 402. The temperature control element 403 can be selected from one or more combinations of a temperature sensor, a heater, or a cooling coil. For example, a temperature sensor can be installed within the medium chamber 402 to monitor the temperature of the temperature-controlled medium in real time and connect to an external control system. Based on the feedback signal, the flow rate or temperature of the medium at the medium inlet 401a can be adjusted to control the temperature of the liquid inside the tank. When rapid heating or auxiliary temperature control is required, a heater or cooling coil can be added to the medium chamber 402 as a supplementary means of active temperature control.

[0084] In one embodiment, the mixing and chopping unit can employ equipment such as a chopper, a pulping machine, or a pounding machine. Choppers mainly include ordinary choppers, variable frequency high-speed choppers, vacuum choppers, and spherical vacuum choppers. Pulping machines use high-speed rotating impellers to mix and pulp materials, suitable for the initial processing of fish paste. Pounding machines use crushing and kneading actions to fully dissolve fish protein, forming a fish paste gel with good viscoelasticity. In this embodiment, the mixing and chopping unit preferably uses a variable frequency high-speed chopper. By adjusting the chopping speed and chopping time, the fish paste base material, micro-puffed salted duck egg white slurry, and auxiliary materials are fully mixed and emulsified, ensuring that the final fish paste product has good gel strength and a delicate texture.

[0085] In one embodiment, the gelation and maturation unit D includes a gelation device and a maturation device. The gelation device can be one of a gelation tunnel, a constant temperature gelation machine, and a gel setting machine. For example, the gelation tunnel is a long box structure with a conveyor belt, a temperature control system, and an insulation layer inside, forming temperature zones along the conveying direction. The constant temperature gelation machine mainly includes a box, a heating device, a temperature sensor, and a shelf. The gel setting machine is a vertical structure with multiple conveyor belts and a steam heating system.

[0086] The maturation equipment can employ one of the following: a hot water immersion device, a steam heating device, or a microwave heating device. For example, the hot water immersion device includes a cooking pot and an automatic continuous cooking machine. The cooking pot consists of a pot body, heating elements, a temperature controller, an inlet, and an outlet. The automatic continuous cooking machine includes a water tank, a conveyor belt, a hot water circulation system, and a temperature control unit. The steam heating equipment includes a steaming chamber and a continuous cooking machine. The steaming chamber is a sealed chamber with steam nozzles and a material rack inside. The continuous cooking machine has a tunnel-type structure with steam nozzles arranged at the top and bottom. The microwave heating equipment includes a microwave heating box and a continuous microwave heater. The microwave heating box consists of a metal cavity, a microwave generator, a waveguide, and a material tray. The continuous microwave heater has a conveyor belt and multiple sets of microwave generators arranged along the conveying direction. In this embodiment, the gelation and maturation unit D can be a combination of a gelation tunnel and an automatic continuous cooking machine.

[0087] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for processing surimi products with added salted duck egg white, characterized in that, Includes the following steps: Fish meat is processed by harvesting, rinsing, and dehydrating to obtain fish paste base material; Salted duck egg whites are placed in a pretreatment unit and aerated and whipped under stirring conditions using jet circulation. The whipping temperature is controlled at 4-10℃ to prepare a micro-expanded salted duck egg white slurry containing uniformly distributed micro-bubbles. After the fish paste base is pounded in the air and then salted, the micro-puffed salted duck egg white slurry and auxiliary materials are added under low temperature conditions and mixed evenly to obtain mixed fish paste. After the mixed fish paste is shaped, it is subjected to gelation treatment and maturation treatment in sequence to obtain fish paste products.

2. The processing method according to claim 1, characterized in that, During the aeration and fermentation process, the mixture is first stirred at a low speed of 60-120 rpm for 2-3 minutes, and then the stirring speed is increased to 300-500 rpm. At the same time, compressed air with a pressure of 0.03-0.05 MPa is circulated through the ejector and the air circulation is continued for 6-10 minutes.

3. The processing method according to claim 1, characterized in that, The rinsing process is a three-stage rinsing process, which involves rinsing with clean water, salt water with a mass concentration of 0.3%, and clean water in sequence; after dehydration, the moisture content of the surimi base material is 80-85%.

4. The processing method according to claim 1, characterized in that, The empty grinding time is 4-5 minutes; the salt grinding time is 5-8 minutes, and the amount of salt added is 2-2.5% of the mass of the fish paste base.

5. The processing method according to claim 1, characterized in that, The low-temperature condition is a temperature controlled at 4-10℃; the auxiliary materials include starch, sugar and compound phosphate, which are added at amounts of 5-10%, 1-4% and 0.1-0.35% of the mass of the surimi base material, respectively, and water is added at 8-12% of the mass of the surimi base material.

6. The processing method according to claim 1, characterized in that, The amount of micro-puffed salted duck egg white slurry added is 15%-35% of the mass of the fish paste base.

7. The processing method according to claim 1, characterized in that, The gelation treatment is to stand at 50°C to 55°C for 30-50 minutes; the maturation treatment is to immerse in water at 90-95°C for 20-25 minutes.

8. A surimi product processing system for adding salted duck egg white for implementing the processing method according to any one of claims 1-7, characterized in that, include: The surimi preparation unit includes a meat extraction device, a rinsing device, and a dehydration device, used to process fish meat into surimi base material; A pretreatment unit is used to aerate and whip salted duck egg whites, the pretreatment unit comprising: The tank has an inlet at the top and an outlet at the bottom, and a liquid outlet and a liquid inlet are formed on the side of the tank. A stirring assembly includes a rotating shaft and at least one blade disposed on the rotating shaft, the upper end of the rotating shaft being rotatably connected to the top of the tank. A jet assembly includes a pump body and an ejector arranged in series. The input end of the pump body is connected to the liquid outlet of the tank through a first pipeline, and the output end of the ejector is connected to the liquid inlet of the tank through a second pipeline. The ejector also has an air inlet. A temperature control assembly includes a jacket fitted onto the outer wall of the tank body, the jacket defining a medium cavity between the jacket and the tank body, and a medium inlet and a medium outlet communicating with the medium cavity respectively formed on the jacket. A mixing and chopping unit is connected to the fish paste preparation unit and the pretreatment unit, respectively. It is used to mix the fish paste base material with the micro-expanded salted duck egg white slurry and auxiliary materials after air pounding and salt pounding to obtain mixed fish paste. A gelling and maturation unit is connected to the mixing and chopping unit. The gelling and maturation unit is used to perform gelling and maturation treatments on the mixed fish paste after it is shaped, so as to obtain fish paste products.

9. The processing system according to claim 8, characterized in that, The outlet end of the second pipe extends horizontally toward the central axis of the tank and then bends upward. The outlet end of the second pipe is located below the blade, and multiple air outlet holes are formed at the end of the outlet end of the second pipe.

10. The processing system according to claim 8, characterized in that, The stirring assembly also includes a drive motor, which is fixed to the top of the tank and the output shaft of the drive motor is connected to the upper end of the rotating shaft.

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