Preparation method of low-salt minced spanish mackerel gel based on egg white protein

Abstract

The invention discloses a preparation method of low-salt minced spanish mackerel gel based on egg white protein, and belongs to the field of food processing. The preparation method comprises the following steps: S1, blending spanish mackerel to obtain minced spanish mackerel meat; s2, adding salt into the minced spanish mackerel meat, and blending to obtain low-salt minced spanish mackerel meat; s3, egg white protein is added into the low-salt minced spanish mackerel for blending, and low-salt egg white protein-minced spanish mackerel is obtained; and S4, performing two-stage heating on the low-salt egg white protein-minced spanish mackerel fillet to obtain the low-salt minced spanish mackerel fillet gel. According to the preparation method disclosed by the invention, the egg white protein is used for replacing spanish mackerel protein, so that the texture property of the low-salt minced spanish mackerel gel is improved, the indexes such as gel strength, water binding capacity and cooking loss of the low-salt minced spanish mackerel gel are ideal, and the network structure is more uniform and compact.

Description

Technical Field

[0001] This invention belongs to the field of food processing, and specifically relates to a method for preparing low-salt mackerel surimi gel based on egg white protein. Background Technology

[0002] Surimi products, typically made from raw or frozen surimi, are processed through grinding, shaping, and gelation, with the addition of auxiliary materials such as salt, to create a gel-like food with a certain degree of elasticity. Surimi products are popular with consumers due to their rich content of essential amino acids and high protein content. Mackerel, an important marine economic fish, is often used to make surimi products because of its tender flesh and easy deboning. During the processing of surimi products, 2%-3% sodium chloride is added to help dissolve and unfold myofibrillar proteins, playing a crucial role in the gelation process. However, excessive salt intake increases the risk of chronic diseases such as hypertension and cardiovascular disease. Directly reducing the salt content often leads to a decline in the quality of the surimi gel, such as reduced water retention, decreased gel strength, and a looser structure. Therefore, there is an urgent need to develop a low-salt mackerel surimi gel product to meet people's health needs.

[0003] Egg white protein is widely used in the food industry due to its rich content of essential amino acids and excellent functional properties. Due to its unique protein structure, egg white protein can rapidly form a gel after a short heat treatment time under low temperature and low concentration conditions. Compared with other proteins such as soy protein isolate or whey protein isolate, egg white protein undergoes intermolecular cross-linking at relatively low temperatures, forming a stable gel network with high strength and good elasticity. This structure allows egg white protein to form a dense and uniform gel even at low concentrations (<3%, w / v), greatly improving its application flexibility and economic feasibility. Although existing technologies disclose the addition of egg white to squid paste, squid belongs to the cephalopod class, and its muscle fiber structure and protein thermal stability are significantly different from those of mackerel (red-fleshed fish). Squid tolerates relatively high initial heating temperatures (above 50°C), but this temperature range coincides with the active region of mackerel endogenous proteases; directly applying this method would lead to severe gel degradation. Furthermore, at salt concentrations as low as 0.5%-1%, mackerel myosin has extremely low solubility and a loose network structure. Simply adding egg white protein at this point not only fails to enhance the gel but also reduces gel strength because the egg white protein, acting as heterogeneous particles, blocks the weak fish protein network. Therefore, how to enable egg white protein to exert its gel-enhancing effect under harsh conditions of low salt and low solubility is the technical problem that this invention aims to solve. Summary of the Invention

[0004] [Technical Issues] When the salt concentration is as low as 0.5% to 1%, the solubility of mackerel myosin is insufficient, resulting in a loose fish paste gel network structure and a decrease in gel strength, texture and water retention. Simply adding egg white protein not only fails to enhance the gel, but also blocks the weak fish protein network due to the "occupancy effect" of egg white protein as heterogeneous particles, affecting the gel quality and overall quality of low-salt fish paste products.

[0005] [Technical Solution] To address the aforementioned problems, this invention provides a method for preparing low-salt mackerel surimi gel based on egg white protein. This method partially replaces mackerel protein with egg white protein to improve its quality. Under a low-salt environment (0.5-1%), the egg white protein is micronized using high-speed pulverization at 12,000-14,000 rpm, binding between the poorly soluble mackerel myofibril bundles to improve the gel properties of the low-salt mackerel surimi. This method has low production costs, requires no toxic or harmful reagents, and features a rational process design that facilitates the comprehensive utilization of raw materials. This preparation method solves the problem of poor gel properties inherent in low-salt surimi and lays the foundation for developing healthier low-salt surimi products.

[0006] The first objective of this invention is to provide a method for preparing a low-salt mackerel surimi gel based on egg white protein, comprising the following steps: S1. Crush the mackerel to obtain mackerel mince; S2. Add salt to the minced mackerel meat, pound it into a paste, and you will get low-salt mackerel paste. S3. Add egg white to the low-salt mackerel paste and pound it to obtain low-salt egg white protein-mackerel paste. S4. The low-salt egg white protein-mackerel surimi is heated in two stages to obtain low-salt mackerel surimi gel.

[0007] In one embodiment of the present invention, in step S1, the mackerel meat is cleaned mackerel meat that has been deheaded, deboned, and skinned.

[0008] In one embodiment of the present invention, in step S1, the rotation speed of the pounding is 1000~1200 rpm, the pounding time is 15~30 s, and the number of pounding is 2~4 times.

[0009] In one embodiment of the present invention, in step S2, the amount of salt added is 0.5 to 1% of the mass of the mackerel mince.

[0010] In one embodiment of the present invention, in step S2, the rotation speed of the pounding is 12000~14000 rpm, the pounding time is 1~2 min, and the number of pounding times is 2~4.

[0011] In one embodiment of the present invention, in step S2, the pulverizer is placed in an ice box for pulverizing. This prevents excessively high temperatures during the pulverizing process from causing protein denaturation.

[0012] In one embodiment of the present invention, in step S3, the amount of egg white protein added (calculated based on the percentage of 1-9% replacing mackerel protein) is 0.2-2.2% of the mass of mackerel surimi; preferably, the amount of egg white protein added in step S3 (calculated based on the percentage of 5% replacing mackerel protein) is 1.2% of the mass of mackerel surimi.

[0013] In one embodiment of the present invention, in step S3, the rotation speed of the pounding is 12000~14000 rpm, the pounding time is 1~2 min, and the number of pounding times is 2~4.

[0014] In one embodiment of the present invention, in step S3, the pulverizer is placed in an ice box for pulverizing. This prevents excessively high temperatures during the pulverizing process from causing protein denaturation.

[0015] In one embodiment of the present invention, in step S4, the heating is a two-stage heating: the first stage is heating at 30-50°C for 20-40 min, and the second stage is heating at 80-100°C for 10-30 min; the cooling is cooling in ice water at a temperature of 0-4°C for 5-15 min.

[0016] A second objective of this invention is to provide a low-salt mackerel surimi gel obtained by the preparation method described above.

[0017] A third objective of this invention is to provide the application of the aforementioned low-salt mackerel surimi gel in the food industry.

[0018] [Beneficial Effects] (1) The preparation method of the present invention uses egg white protein to replace mackerel protein, which improves the textural properties of low-salt mackerel surimi gel, and makes the gel strength, water holding capacity and cooking loss of low-salt surimi gel all show ideal effects, and the network structure is more uniform and dense.

[0019] (2) The preparation method of the present invention is simple, easy to implement, contains no additives, is green and safe, reduces costs, and is suitable for industrial production.

[0020] (3) In this invention, a high-speed pounding process of 12,000-14,000 rpm is used in a low-salt (0.5-1%) environment. Compared with conventional mixing, this process micronizes the egg white protein and binds it between the insufficiently soluble mackerel myofibril bundles. If a conventional speed such as ordinary beating is used, the egg white protein will clump together, hindering the gelation of the low-salt fish paste.

[0021] (4) In the case of low salt (0.5-1%) and without the use of phosphate, the present invention achieves texture properties comparable to or even better than those of the high salt control group by using only egg white protein through a specific process. Attached Figure Description

[0022] Figure 1 The gel strength of the low-salt mackerel surimi gels in Examples 1-5 and Comparative Examples 1-2 is given.

[0023] Figure 2 The water-holding capacity of low-salt mackerel surimi gels in Examples 1-5 and Comparative Examples 1-2 is shown.

[0024] Figure 3 The cooking loss of low-salt mackerel surimi gel in Examples 1-5 and Comparative Examples 1-2 is considered.

[0025] Figure 4 The apparent morphology and microstructure of low-salt mackerel surimi gels in Examples 1-5 and Comparative Examples 1-2 are shown. Detailed Implementation

[0026] The egg white protein used in the embodiments of this invention is from Jiangsu Kangde Egg Industry Co., Ltd.

[0027] Test methods 1. Determination of gel strength: The gel strength of shrimp paste gel was measured using a TA-XT Plus texture analyzer. The following parameters were set: a P / 0.5 metal spherical probe was used; gel strength testing mode was employed; the sample diameter was set to 20 mm; and the sample height to 10 mm. The testing speeds before, during, and after the test were set to 1.5 mm / s, 1.0 mm / s, and 1.0 mm / s, respectively; the compression ratio was 40%; and the trigger force was 5.0 g. The gel strength was calculated using the following formula. To ensure data reliability, all samples were tested six times, and the final results are expressed as mean ± standard deviation.

[0028] Calculate gel strength using the following formula: Gel strength (g·cm) = breaking force (g) × breaking distance (cm).

[0029] 2. Determination of textural properties: The textural properties of the surimi gel were evaluated using a TA-XT Plus texture analyzer. The following parameters were set: a P / 50 probe was used, TPA testing mode was employed, the sample diameter was 20 mm, and the sample height was 10 mm. Testing speeds were set to 1.5 mm / s, 1.0 mm / s, and 1.0 mm / s before, during, and after the test, respectively; the compression ratio was 40%, and the trigger force was 5.0 g. The textural properties were evaluated for hardness, elasticity, cohesiveness, and chewiness. To ensure data reliability, all samples were tested six times, and the final results are expressed as mean ± standard deviation.

[0030] 3. Determination of water retention capacity: Each fish paste gel sample was cut into small pieces weighing approximately 1g, and the initial weight was recorded as M1. Each piece was wrapped in 2-3 sheets of filter paper and placed in a 50 mL centrifuge tube. The water-holding capacity was determined by centrifugation (10000 rpm, 10 min, 4 ℃). After centrifugation, the sample surface was dried with filter paper, and the weight after centrifugation was recorded as M2. To ensure data reliability, all samples were tested three times in total. The final results are expressed as mean ± standard deviation.

[0031] Calculate water retention capacity using the following formula: WHC / % = M2 / M1 × 100.

[0032] 4. Determination of cooking loss: Each sample was divided into three equal groups and placed into 50 mL centrifuge tubes. The samples were accurately weighed and the mass before cooking was recorded as m1. After heat treatment and cooling, the samples were wiped dry with paper towels, weighed, and the mass after cooking was recorded as m2. The weight difference between the surimi gel before and after water bath heating, divided by the weight of the unheated gel, was used to calculate the cooking loss according to the following equation, expressed as percentiles. To ensure data reliability, all tests were performed three times, and the final results are expressed as mean ± standard deviation.

[0033] Calculate cooking loss using the following formula: Cooking loss (%) = (m1-m2) / m1.

[0034] 5. Determination of microstructure: The microstructure of the samples was observed using an SU8000 cold field scanning electron microscope. First, the surimi gel was placed on a copper sample holder, slightly protruding upwards to facilitate cryogenic fracture. The samples were cryogenically frozen in liquid nitrogen at -210 °C, then transferred from a vacuum chamber to a cryogenic preparation chamber for cryogenic fracture. Sublimation was performed at -60 °C for 40 min, followed by platinum sputtering at 10 mV for 60 s. Afterwards, the samples were transferred to the observation chamber for imaging observation at an accelerating voltage of 10 kV, and representative images from different fields of view were collected.

[0035] Example 1 A method for preparing low-salt mackerel surimi gel based on egg white protein, comprising the following steps: S1. Remove the head, skin, and bones from the mackerel to obtain clean mackerel meat; S2. Pound the clean mackerel meat at 1000 rpm for 15 seconds to obtain mackerel minced meat. S3. Add 1% salt by weight of the mackerel meat to the mackerel mince, and pound it three times at 14000 rpm for 40 seconds each time to obtain low-salt mackerel paste. S4. Add egg white protein to the low-salt mackerel paste. The amount of egg white protein added (calculated based on the percentage of 1% replacing mackerel protein) is 0.2% of the mass of mackerel paste. Pound at 14000 rpm three times, 40 seconds each time, to obtain low-salt egg white protein-mackerel paste. S5. Heat the low-salt egg white protein-mackerel paste at 40 ℃ for 30 min, then heat at 90 ℃ for 20 min, and quickly cool in ice water to obtain low-salt egg white protein-mackerel paste gel.

[0036] Example 2 A method for preparing low-salt mackerel surimi gel based on egg white protein differs from Example 1 in that, in step S4, the amount of egg white protein added (calculated based on the percentage of mackerel protein replacing 1%) is changed from 0.2% of the mackerel surimi mass to 0.7% of the mackerel surimi mass (calculated based on the percentage of mackerel protein replacing 3%).

[0037] Example 3 A method for preparing low-salt mackerel surimi gel based on egg white protein differs from Example 1 in that, in step S4, the amount of egg white protein added (calculated based on the percentage of mackerel protein replacing 1%) is changed from 0.2% of the mackerel surimi mass to 1.2% of the mackerel surimi mass (calculated based on the percentage of mackerel protein replacing 5%).

[0038] Example 4 A method for preparing low-salt mackerel surimi gel based on egg white protein differs from Example 1 in that, in step S4, the amount of egg white protein added (calculated based on the percentage of mackerel protein replacing 1%) is changed from 0.2% of the mackerel surimi mass to 1.7% of the mackerel surimi mass (calculated based on the percentage of mackerel protein replacing 7%).

[0039] Example 5 A method for preparing low-salt mackerel surimi gel based on egg white protein differs from Example 1 in that, in step S4, the amount of egg white protein added (calculated based on the percentage of mackerel protein replaced by 1%) is replaced with the amount of egg white protein added being 0.2% of the mass of mackerel surimi (calculated based on the percentage of mackerel protein replaced by 9%), which is 2.2% of the mass of mackerel surimi.

[0040] Comparative Example 1 Add 1% salt by weight of mackerel meat to the mackerel minced meat and pound it three times at 14000 rpm for 40 seconds each time to obtain a low-salt fish paste gel control group.

[0041] Comparative Example 2 Add 2.5% salt by weight of mackerel meat to the mackerel minced meat and pound it three times at 14000 rpm for 40 seconds each time to obtain a high-salt fish paste gel control group.

[0042] The obtained fish paste gel was subjected to performance testing, and the test results are as follows: Table 1. Effect of egg white protein substitution rate on the gel texture properties of low-salt mackerel surimi.

[0043] This invention discovers that, under low-salt conditions (0.5-1%), a high-speed pounding process at 12,000-14,000 rpm is effective. Compared to conventional mixing, this process micronizes the egg white protein, binding it between the poorly soluble myofibril bundles. If conventional speeds, such as ordinary beating, are used, the egg white protein will clump together, hindering gelation in the low-salt fish paste. The first stage of heating in this invention is strictly controlled at 30-50°C. This invention utilizes the mild conditions of 30-50°C to, on the one hand, leverage the unique low-temperature gelation characteristics of mackerel to induce the unfolding of myosin heavy chains, and on the other hand, avoids the highly active region of mackerel cathepsins (50-70°C), while simultaneously providing a time window for the incompletely denatured egg white protein to undergo disulfide bond exchange with the fish protein.

[0044] Table 1 shows the TPA test results for Examples 1-5, Comparative Example 1, and Comparative Example 2. As can be seen from Table 1, the hardness, cohesiveness, and chewiness of Examples 1-5 are significantly higher than those of Comparative Example 1 and Comparative Example 2. With the increase of egg white protein replacement rate, the hardness, cohesiveness, and chewiness of the low-salt surimi gel show a trend of first increasing and then decreasing. When the egg white protein replacement rate reaches 5% (Example 3), the hardness, elasticity, cohesiveness, and chewiness of the low-salt surimi gel reach their maximum, significantly increasing by 60.18%, 4.49%, 17.74%, and 100.03% respectively compared to the low-salt control group (Comparative Example 1). This may be because egg white protein acts as a filler in the low-salt mixed surimi gel, thereby improving its textural properties.

[0045] Figure 1 The results are the gel strength test results for Examples 1-5, Comparative Example 1, and Comparative Example 2. From... Figure 1 It can be seen that the gel strength of Examples 1-5 is significantly higher than that of Comparative Examples 1 and 2. When the egg white protein replacement rate reaches 5% (Example 3), the gel strength of the low-salt surimi reaches its maximum, increasing by 58.9% compared to the low-salt control group (Comparative Example 1) and by 22.75% compared to the high-salt control group (Comparative Example 2). However, further increasing the egg white protein replacement rate will lead to a decrease in gel strength, a result consistent with the TPA experiment results.

[0046] Figure 2 The results are the cooking loss test results for Examples 1-5, Comparative Example 1, and Comparative Example 2. From... Figure 2 It can be seen that the cooking loss rates of Examples 1-5 are significantly lower than those of Comparative Examples 1 and 2. Cooking loss reflects the water retention capacity during the formation of surimi gel; the lower the cooking loss value, the less water, protein, and other components are lost during heating. The cooking loss reached its minimum when the egg white protein replacement rate was 5% (Example 3), a reduction of 46.6% compared to the low-salt control group (Comparative Example 1). Adding egg white protein helps reduce the cooking loss of low-salt surimi gel.

[0047] Figure 3 The results are from the water-holding capacity tests of Examples 1-5, Comparative Example 1, and Comparative Example 2. Figure 3 It can be seen that the water-holding capacity of Examples 1-5 is significantly higher than that of Comparative Examples 1 and 2. The water-holding capacity reaches its maximum when the egg white protein replacement rate is 5% (Example 3), which is 21.19% higher than that of the low-salt control group (Comparative Example 1). The results indicate that adding egg white protein is beneficial for maintaining moisture in the gel and increasing the water-holding capacity of low-salt surimi gel.

[0048] Figure 4 The results show the apparent morphology and microstructure measurements of Examples 1-5, Comparative Example 1, and Comparative Example 2. From... Figure 4As can be seen from A, the samples in Comparative Example 1 and Comparative Example 2 have a rougher appearance and irregular pores. The sample with the smoothest and most uniform surface was achieved when the egg white protein replacement rate was 5% (Example 3). Figure 4 As can be seen from B, the gel networks of Comparative Example 1 and Comparative Example 2 exhibit a coarse structure with large and unevenly distributed pores. With the increase of egg white protein replacement rate, the structure of the low-salt composite gel gradually becomes more uniform and dense, and the pore size also decreases. At an egg white protein replacement rate of 5% (Example 3), the low-salt surimi gel has the densest network structure and the smallest pore size. The results indicate that adding EWP can make the gel network structure denser, thereby improving the textural properties and water-holding capacity of the low-salt surimi gel.

[0049] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing low-salt mackerel surimi gel based on egg white protein, characterized in that, Including the following steps: S1. Crush the mackerel to obtain mackerel mince; S2. Add salt to the minced mackerel meat, pound it into a paste, and you will get low-salt mackerel paste. S3. Add egg white to the low-salt mackerel paste and pound it to obtain low-salt egg white protein-mackerel paste. S4. The low-salt egg white protein-mackerel surimi is heated in two stages to obtain low-salt mackerel surimi gel.

2. The preparation method according to claim 1, characterized in that, In step S1, the pounding speed is 1000~1200rpm, the pounding time is 15~20s, and the number of poundings is 2~4.

3. The preparation method according to claim 1, characterized in that, In step S2, the amount of salt added is 0.5 to 1% of the mass of the mackerel mince.

4. The preparation method according to claim 1, characterized in that, In step S2, the pounding speed is 12000~14000 rpm, the pounding time is 1~2 min, and the number of pounding times is 2~4.

5. The preparation method according to claim 1, characterized in that, In step S3, the pounding speed is 12000~14000 rpm, the pounding time is 1~2 min, and the number of pounding times is 2~4.

6. The preparation method according to claim 1, characterized in that, In step S3, the pounding machine is placed in the ice box to perform the pounding operation.

7. The preparation method according to claim 1, characterized in that, In step S3, the amount of egg white protein added is 0.2-2.2% of the weight of the mackerel surimi.

8. The preparation method according to claim 1, characterized in that, In step S4, the heating is carried out in two stages: the first stage is heated at 30~50 ℃ for 20~40 min, and the second stage is heated at 80~100 ℃ for 10~30 min; the cooling is carried out in ice water at a temperature of 0~4 ℃ for 5~15 min.

9. The low-salt mackerel surimi gel obtained by any of the preparation methods described in claims 1 to 8.

10. The application of the low-salt mackerel surimi gel according to claim 9 in the food industry.

Images