A hairtail fish surimi gel containing tuna fish bones prepared by an extrusion puffing technique

Abstract

The present invention provides a hairtail fish mince gel containing tuna fish bones prepared by an extrusion puffing technology and a preparation method thereof. The present invention uses a single-screw extrusion puffing technology with low energy consumption and high efficiency to prepare nano tuna fish bones, which is conducive to large-scale and high-yield production. The present invention can significantly improve the quality of fish mince gel and is expected to replace inorganic calcium salts such as calcium chloride as a new type of gel strengthener; the present invention can solve problems such as poor calcium supplementation effect, low absorption rate, and residue in the body to form stones in calcium supplementation products on the market, so as to meet people's needs for efficient calcium supplementation.

Description

Technical Field

[0001] The present invention relates to the field of biotechnology, and particularly to a hairtail fish mince gel containing tuna fish bones prepared by extrusion puffing technology. Background Art

[0002] Tuna is a world-recognized high-end marine economic fish. However, a large amount of by-products are generated during the processing of tuna, among which fish bones are the main solid by-products, accounting for 20%-30% of the total fish body mass. Tuna fish bones are rich in calcium compounds (57.2%) and proteins (33.1%) and have high bioavailability, being potential sources of low-cost bio-calcium and bone collagen peptides. However, most of the fish bones are used for animal feed or directly discarded during the production and processing, resulting in serious waste of aquatic resources.

[0003] Research shows that making fish bones into powder can significantly improve the edible value and economic value of fish bones. The properties such as the release degree, fluidity, solubility, conductivity, and water-holding capacity of calcium ions and phosphate groups in fish bone powder will increase with the decrease of its particle size. In addition, if the fish bone particle size is too large, such as greater than 100 μm, it will produce a strong sandy feeling, while when the particle size is reduced to the ultra-fine powder grade (<100 μm), there is almost no sandy feeling. Ultra-fine powders can be further divided into micron-sized (1-100 μm), sub-micron (0.1-1.0 μm), and nano-sized (1-100 nm) according to particle size. Among them, the huge specific surface area of nano-particles and sub-micron particles endows them with strong bioavailability and has been gradually applied to fields such as food production and drug preparation. However, the strong network structure composed of calcium, phosphate groups, and collagen fibers in fish bones makes it difficult to ultra-finely pulverize them. At present, researchers often use ball milling to prepare high-purity nano-sized fish bone powder, and use air jet milling and colloid mill methods to prepare ultra-fine fish bone powder such as micron-sized or sub-micron-sized. However, these methods all have problems such as long time consumption, high energy consumption, and low production efficiency, and have great limitations in production scale. Summary of the Invention

[0004] In view of the above problems, the present invention provides a hairtail fish mince gel containing tuna fish bones prepared by extrusion puffing technology and its preparation method.

[0005] On the one hand, the present invention provides a hairtail fish mince gel containing tuna fish bones prepared by extrusion puffing technology, which includes the following. Calculated by mass percentage, the proportions of each component in the hairtail fish mince gel are as follows: hairtail fish mince (with a moisture content of 74.19%): 75.55%, NaCl: 2.5%, water: 21.95%, and the total weight of the three is 100%; the addition amount of EE-FB is 0.75% of the total weight of hairtail fish mince, NaCl, and water.

[0006] Among them, the tuna nano fish bone EE-FB prepared based on the extrusion puffing technology is prepared by the following method:

[0007] 1) Cut the fish bones into small sections about 5 cm long, blanch them in boiling water for 20 min, rinse them thoroughly with tap water, dry them at 70 °C, and preliminarily crush the fish bones with a pulverizer.

[0008] 2) Mix the preliminarily crushed fish bones, rice, and corn starch evenly, and process them under the conditions of 130 °C and 400 rpm with a single-screw extruder. The obtained product is pulverized again with a pulverizer to obtain the extruded puffing fish bone powder EE-FB.

[0009] Preferably, the EE-FB is EE-FB(40.00%), and the EE-FB(40.00%) means that the weight percentages of the preliminarily crushed fish bones: rice: corn starch in step 2) are 40.00%: 52.50%: 7.50%.

[0010] The present invention uses the single-screw extrusion puffing technology with low energy consumption and high efficiency to prepare tuna nano fish bones, which is conducive to large-scale and high-yield production.

[0011] On the other hand, the present invention provides a preparation method of the fish mince gel containing the tuna fish bones prepared by the extrusion puffing technology, which includes the following steps:

[0012] 1) The frozen hairtail fish mince is thawed overnight at 4 °C, chopped and chopped for 2 min, and salted with NaCl for 2 min.

[0013] 2) Add EE-FB, add ice water, adjust the moisture content, and chop for 3 min. The production temperature is controlled below 10 °C.

[0014] 3) After the fish mince is enema-molded, it is gelatinized by the two-stage heating method, and stored at 4 °C after being cooled with ice water.

[0015] Preferably, the proportions of the components in the hairtail fish mince gel in the above steps are as follows: frozen hairtail fish mince (moisture content is 74.19%): 75.55%, NaCl: 2.5%, water: 21.95%, and the total weight of the three is 100%; the addition amount of EE-FB is 0.75% of the total weight of the hairtail fish mince, NaCl, and ice water.

[0016] Preferably, the two-stage heating method in step 3) means heating at 40 °C for 30 min and heating at 90 °C for 20 min.

[0017] The present invention has the following advantages:

[0018] (1) Compared with the existing technologies which have problems such as long time consumption, high energy consumption, high production cost and being not conducive to large-scale production, the present invention adopts a single-screw extrusion puffing technology with low energy consumption to improve the preparation rate of nano fish bones; it has the characteristics of high efficiency and low energy consumption.

[0019] (2) The present invention can significantly improve the quality of surimi gel and is expected to replace inorganic calcium salts such as calcium chloride to become a new type of gel strengthener; the present invention can solve the problems in calcium supplement products on the market such as poor calcium supplement effect, low absorption rate, and residue in the body causing stones, etc., so as to meet people's demand for efficient calcium supplementation. Description of the Drawings

[0020] Figure 1 (a) is a graph of the particle size of extruded and puffed fish bone powder with different fish bone powder ratios, (b) is a morphology graph of N-FB and EE-FB, (c) is a graph of the particle size of N-FB and EE-FB, and (d) is a particle size distribution graph of N-FB and EE-FB.

[0021] Figure 2 is the FT-IR graph of N-FB and EE-FB.

[0022] Figure 3 is a surimi gel graph.

[0023] Figure 4 is (a) a graph of the effects of adding NaCl, rice + corn starch, N-FB, CaCl2 and EE-FB on the water holding capacity and cooking loss of surimi gel; (b) is a graph of the effects of adding NaCl, rice + starch, N-FB (40.00%), CaCl2 and EE-FB (40.00%) on the relaxation time of surimi gel.

[0024] Figure 5 (a) is a graph of the effects of adding NaCl, rice + starch, N-FB (40.00%), CaCl2 and EE-FB (40.00%) on the storage modulus of surimi gel; (b) is a graph of the effects of adding NaCl, rice + starch, N-FB (40.00%), CaCl2 and EE-FB (40.00%) on the loss modulus of surimi gel.

[0025] Figure 6 is the chemical force of adding NaCl, rice + starch, N-FB (40.00%), CaCl2 and EE-FB (40.00%) on surimi gel.

[0026] Figure 7 is a graph of the effects of adding NaCl, rice + starch, N-FB (40.00%), CaCl2 and EE-FB (40.00%) on the secondary structure.

[0027] Figure 8 SEM images of surimi gels added with NaCl, rice + starch, N-FB (40.00%), CaCl2, and EE-FB (40.00%). ((a) NaCl, (b) rice + starch, (c) 0.75% N-FB (40.00%), (d) 0.2% CaCl2, (e) 0.75% EE-FB (40.00%). Detailed implementation manners

[0028] Example 1

[0029] 1) Cut the fish bones into small pieces about 5 cm long, blanch them in boiling water for 20 min, rinse them thoroughly with tap water, dry them at 70 °C, and preliminarily crush the fish bones using a pulverizer;

[0030] 2) According to the mass percentages in Table 1, mix the preliminarily crushed fish bones (0 - 40.00%), rice, and corn starch evenly, and then process them using a single-screw extruder under the conditions of 130 °C and a rotation speed of 400 rpm. The obtained product is crushed again using a pulverizer to obtain extruded expanded fish bone powder EE-FB with different proportions of fish bone powder content;

[0031] Table 1

[0032] Fish bone meal / % Rice / % Corn starch / % 0.00 87.50 12.50 5.00 83.13 11.87 10.00 78.75 11.25 15.00 74.38 10.62 20.00 70.00 10.00 25.00 65.63 9.37 30.00 61.25 8.75 35.00 56.87 8.13 40.00 52.50 7.50

[0033] Use a laser particle size distribution analyzer to measure the particle size of the fish bone powder, and compare and study the particle size of EE-FB with different proportions of fish bone powder content.

[0034] Measurement of the particle size of fish bone powder

[0035] That is, use pure water as the dispersion medium, use 2% (NaPO3)6 as the dispersant, and ultrasonicate for 15 min to make the sample disperse evenly. Analyze the results using Zetasizer Software. The particle size of the fish bone powder is expressed by the average diameter and particle size distribution. The particle size diagrams of extruded expanded fish bone powder with different proportions of fish bone powder content are shown in Figure 1 a. The particle size of the extruded expanded fish bone powder is inversely proportional to the fish bone powder content. Considering its calcium content, the extrusion conditions are determined as follows: preliminarily crushed fish bones (40.00%), rice (52.50%), and corn starch (7.50%).

[0036] Example 2

[0037] 1) Mix the preliminarily crushed fish bones (40.00%), rice (52.50%), and corn starch evenly according to the mass percentages, and then process them using a single-screw extruder under the conditions of 130 °C and a rotation speed of 400 rpm. The obtained product is crushed again using a pulverizer to obtain extruded expanded fish bone powder EE-FB (40.00%);

[0038] 2) According to the mass percentage, take the preliminarily crushed fish bones (40.00%), rice (52.50%), and corn starch (7.50%). First, process the rice and starch with a single-screw extrusion expander at 130 °C and a rotation speed of 400 rpm. Then, mix them evenly with the preliminarily crushed fish bones and use a pulverizer to crush them to obtain the unextruded and expanded fish bone powder N-FB (40.00%).

[0039] A comparative study was conducted on the extruded and expanded fish bone powder EE-FB (40.00%) and the unextruded and expanded fish bone powder N-FB (40.00%). The diagrams of the fish bone powder before and after the extrusion and expansion treatment of the fish bone powder are shown in Figure 1b. The extruded and expanded fish bone powder has a darker color than the unextruded one. The particle size results are as shown in Figure 1 Figures 1c and 1d. The results show that the average particle size of the unextruded and expanded fish bone powder N-FB (40.00%) is 465.03 nm, of which only 10.80% is less than 100 nm (nanoscale), and 17.24% of the fish bone powder particles have a particle size higher than 1000 nm (micrometer scale, with a gritty feeling). After extrusion and expansion, the average particle size of the fish bone powder EE-FB (40.00%) reaches 308.07 nm, which is significantly smaller than that of the N-FB (40.00%) group. Approximately 59.41% of the fish bone powder particles belong to the sub-micrometer scale (100 - 1000 nm), and approximately 40.59% of the fish bone powder particles belong to the nanoscale (1 - 100 nm).

[0040] Example 3

[0041] Use an FT-IR spectrometer to comparatively analyze the chemical structures of the two groups of fish bone powders, EE-FB (40.00%) and N-FB (40.00%). Mix approximately 1 mg of fish bone powder with KBr (1:100, w / w), manually press it into a translucent thin slice, use blank KBr as the scanning background, and the FT-IR scanning range is 400 - 4000 cm -1 , with a resolution of 2 cm -1 , and scan 64 times.

[0042] Figure 2 These are the FT-IR results of N-FB (40.00%) and EE-FB (40.00%). The spectra of the two are basically the same, and both expose many hydroxyl groups and phosphate groups. Thus, it can be seen that the extrusion and expansion process under high temperature and high pressure does not destroy the original groups and structures of the fish bones.

[0043] Example 4

[0044] Compare and study the main chemical components of two groups of fish bone meal, EE-FB (40.00%) and N-FB (40.00%). The moisture content of the samples was determined by the direct drying method in GB 5009.3-2016 "Determination of Moisture in Foods"; the crude protein content of the samples was determined by the Kjeldahl method in GB 5009.5-2016 "Determination of Protein in Foods"; the fat content of the samples was determined by the Soxhlet extraction method in GB 5009.6-2016 "Determination of Fat in Foods"; the ash content of the samples was determined by the total ash determination method in GB 5009.4-2016 "Determination of Ash in Foods"; the calcium content of the samples was determined by GB 5009.268-2016 "Determination of Multi-elements in Foods".

[0045] The determination results of the moisture, crude protein, fat, ash and calcium element contents of two groups of fish bone meal, unextruded and expanded (N-FB) (40.00%) and extruded and expanded EE-FB (40.00%), are shown in Table 2. The contents of each component in the EE-FB (40.00%) group were significantly lower than those in the N-FB (40.00%) group, but the ash contents of the two groups were the highest, and the protein contents were the second highest. The main component of the ash is hydroxyapatite, which contains abundant mineral elements such as calcium and phosphorus, and the calcium content in the EE-FB (40.00%) group reached 40.00% of the total ash content, higher than 37.06% in the N-FB (40.00%) group. It can be seen that extrusion and expansion can efficiently produce submicron-nano fish bone meal, which has finer particle size and is a protein raw material rich in calcium source, and is more suitable for the development of high-value products.

[0046] Table 2 Basic components and contents of fish bone meal (%)

[0047]

[0048] Note: Different lowercase letters in the same column indicate significant differences (P<0.05), the same below.

[0049] Example 5

[0050] The frozen hairtail surimi (with a moisture content of 74.19%) was thawed overnight at 4°C, chopped and chopped for 2 min, salted with NaCl for 2 min, and ice water was added. The weight ratio of frozen hairtail surimi: NaCl: ice water was 75.55%: 2.5%: 21.95%, and five parallel groups were made;

[0051] One group was not added with anything (NaCl group), and the other four groups were respectively added with 1.125% rice + corn starch (the used was 0.00% fish bone: 87.50% rice: 12.50% corn starch in Table 1 of Example 1), 0.75% N-FB (40.00%), 0.2% CaCl2, and 0.75% EE-FB (40.00%) based on the total mass of hairtail surimi gel. (Both N-FB and EE-FB were calculated based on the amount of fish bone powder, and the calcium content of 0.2% CaCl2 was equivalent to that of fish bone powder). After chopping for 3 min, the production temperature was controlled below 10 °C. After the surimi was enema-formed into surimi paste, it was gelated into surimi gel by the two-stage heating method (40 °C - 30 min; 90 °C - 20 min), and stored at 4 °C after being cooled with ice water. The effects of fish bone powder prepared with different components on the properties of surimi gel were studied by comparison.

[0052] Measurement of surimi gel color difference

[0053] The test samples were cut into cylinders with a thickness of 20 mm and equilibrated at room temperature for 30 min. The L* (brightness), a* (red / green), and b* (yellow / blue) values of surimi gels of the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group (the first to fifth groups respectively) were measured using a color difference meter. According to the formula W = 100 - [(100 - L*)2 + a*2 + b*2] 1 / 2 the whiteness value was calculated. The results are as Figure 2 and Table 3.

[0054] As can be seen from Table 3, compared with the NaCl surimi gel group, there was no significant difference in the L* (brightness) of the surimi gel in the 0.2% CaCl2 group, the b* (yellowness) value decreased significantly, and the W (whiteness) increased significantly; there were no significant differences in L*, a*, b*, and W of the surimi gel in the rice + starch group; while the L* and W of the surimi gel groups of 0.75% N-FB (40.00%) and 0.75% EE-FB (40.00%) decreased significantly, and b* increased significantly. In comparison, the color difference change of the EE-FB (40.00%) surimi gel group was greater ( Figure 3 ).

[0055] Table 3

[0056]

[0057] Measurement of the texture properties of fish bone gel

[0058] Cut the sample to be tested into 20×20 mm cylinders. Use a P / 0.5S spherical probe to measure the gel strength of surimi gels in the NaCl group, rice + starch group, 0.75% N-FB(40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB(40.00%) group. The speeds before, during, and after the test are 1.0 mm·s -1 、1.0 mm·s -1 、10 mm·s -1 , the trigger force is 5 g, the deformation is 50%, measure and record the breaking force (g) and deformation amount (mm). The gel strength of surimi is expressed as: gel strength = breaking force (g) × breaking distance (mm). Use a cylindrical aluminum probe with a diameter of 35 mm (P / 35) to conduct two-cycle compression tests on the gel cylinder. The speeds before, during, and after the test are 1.0 mm·s -1 、1.0 mm·s -1 、10 mm·s -1 , the trigger force is 5.0 g, the deformation amount is 50%, the pressing height is 10 mm, measure and analyze the hardness, elasticity, chewiness, and adhesiveness of the sample. The results are shown in Table 4.

[0059] As can be seen from Table 4, the breaking force and breaking distance of the surimi gel added with 0.75% EE-FB(40.00%) are the largest, and its gel strength is also the strongest (1249.65±14.09 g·mm), which is significantly higher than other groups. Compared with the NaCl surimi gel group, the hardness, elasticity, chewiness, and adhesiveness of the surimi added with 0.75% EE-FB(40.00%) are significantly increased; while the hardness, chewiness, and adhesiveness of the surimi gel added with rice + starch are significantly decreased; adding 0.75% N-FB(40.00%) can significantly enhance the strength, hardness, chewiness, and adhesiveness of surimi, but cannot enhance its elasticity; adding 0.2% CaCl2 can significantly increase the strength, elasticity, chewiness, and adhesiveness of surimi gel, but at the same time, it also causes a decrease in the hardness of surimi gel. Through comprehensive analysis, 0.75% EE-FB(40.00%) has the best effect on improving the texture properties of surimi.

[0060] Table 4

[0061]

[0062] Determination of water holding capacity and cooking loss rate of fish gel

[0063] Accurately weigh 3.0 g (W1) of surimi gel samples from the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group respectively. After wrapping with three layers of filter paper, centrifuge at 4 °C and 5000×g for 15 min in a 50 mL centrifuge tube, weigh again (W2), and calculate the water holding capacity (WHC) according to the formula: WHC (%) = W2 / W1 × 100.

[0064] Weigh the sliced surimi samples of each group (m1) and put them into a sealed cooking bag. Keep them in a constant temperature water bath at 90 °C for 20 min. Quickly take out the surimi gel, gently wipe off the surface liquid and weigh again (m2). Calculate the cooking loss rate according to the formula: cooking loss rate (%) = (m1 - m2) / m1 × 100.

[0065] The results of the water holding capacity and cooking loss rate of surimi gels in different treatment groups are as Figure 4 shown in a. The water holding capacity of the surimi gel added with 0.75% EE-FB (40.00%) is significantly higher than that of other groups, while the cooking loss is significantly lower than that of other groups; the water holding capacity of the surimi gel added with CaCl2 is significantly lower than that of other groups, while the cooking loss is significantly higher than that of other groups; the water holding capacity and cooking loss rate of the surimi gels in the 0.75% N-FB (40.00%), NaCl, and rice + starch groups are all at the same intermediate level. Therefore, 0.75% EE-FB (40.00%) can improve the water holding capacity of surimi gel and the strength of the gel network structure during thermal processing.

[0066] Low-field nuclear magnetic resonance measurement of surimi gel

[0067] Take the surimi gel samples of the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group with a height of 2.5 cm and place them in a nuclear magnetic tube. Measure the transverse relaxation time constant T2 using a nuclear magnetic resonance analyzer, and calculate the proportion of different types of water content according to the peak areas in the obtained relaxation time T2 spectrum.

[0068] Figure 4b is the low-field nuclear magnetic resonance results of different processed surimi gels. The calculation results show that the bound water content in the surimi gels added with rice + starch, 0.75% N-EB (40.00%), 0.2% CaCl2, and 0.75% EE-FB (40.00%) increased by 1.06%, 3.08%, 0.39%, and 1.72% respectively compared with the NaCl group. That is, EE-FB (40.00%) can maximize the interaction between the gel network and water molecules, promoting the transformation of free water in surimi gels into more stable bound water. This is consistent with the results of water-holding capacity and cooking loss rate, corroborating that EE-FB can effectively improve the water-holding capacity of surimi gels.

[0069] Determination of rheological properties of surimi gels

[0070] The storage modulus (G’) and loss modulus (G”) of surimi gels in the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group were measured using a rheometer. That is, the surimi gel was evenly smeared on the test platform, sealed with silicone oil, and measured using the temperature scanning mode. The measurement parameters were: oscillation frequency of 1 Hz, strain of 2%, parallel plate spacing of 1000 μm, heating scanning range of 20 - 90 °C, and heating rate of 4 °C·min -1 .

[0071] The results are shown in Figure 5 , and the change trends of G’ and G” of the surimi gel proteins in the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group are as Figure 4As shown, the storage modulus value (G’) of each group of surimi gels was always greater than the loss modulus (G”), indicating that they had high elasticity. During the process of temperature rising from 20 °C to 90 °C, the surimi groups such as the NaCl group, the rice + starch group, and the 0.2% CaCl2 group showed similar rheological properties, that is, the G’ value reached the lowest point at 55 - 60 °C, then slowly increased, and basically remained unchanged after 80 °C. In contrast, the surimi gels of the 0.75% N-FB (40.00%) group and the 0.75% EE-FB (40.00%) group both reached the lowest point at about 43 °C, then increased sharply, and reached the maximum G’ value at 55 °C and 80 °C respectively. Among them, the maximum G’ value of the EE-FB group of surimi gel could reach 11136.5 Pa, much higher than other groups. At the same time, the change trend of G” in different treatment groups was similar to that of G’. The G” value of the EE-FB group of surimi gel protein was the largest and significantly higher than other groups. The results of the rheological properties of surimi gel protein showed that the EE-FB (40.00%) group had the highest protein cross-linking density, so it could show the best protein gel elasticity (Table 4), that is, EE-FB (40.00%) could improve the rheological properties of surimi gel protein to the greatest extent.

[0072] Determination of Chemical Forces in Surimi Gel

[0073] Accurately weigh 3.0 g of surimi gel samples from the NaCl group, the rice + starch group, the 0.75% N-FB (40.00%) group, the 0.2% CaCl2 group, and the 0.75% EE-FB (40.00%) group, and mix and homogenize them with 10 mL of different chemical force-destroying reagents such as SA (0.05 mol·L -1 NaCl), SB (0.6 mol·L -1 NaCl), SC (0.6 mol·L -1 NaCl + 1.5 mol·L -1 urea), SD (0.6 mol·L -1 NaCl + 8 mol·L -1 urea), SE (0.6 mol·L -1 NaCl + 8 mol·L -1 urea + 0.05 mol·L -1 β-mercaptoethanol), stir at 4 °C for 1 h and then centrifuge, and measure the protein concentration in the supernatant. The chemical forces are expressed by the difference in protein concentration in the supernatant between groups: the ionic bond is the difference between SB and SA, the hydrogen bond is the difference between SC and SB, the hydrophobic force is the difference between SD and SC, and the disulfide bond is the difference between SE and SD.

[0074] During the formation of surimi gel protein, the changes in chemical forces such as ionic bonds, hydrophobic interactions, and disulfide bonds, which are closely related in the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group, are as follows Figure 6 shown. Compared with the NaCl group, the ionic bonds in the 0.75% EE-FB (40.00%) group decreased (decreased by 1.08 g·L -1 ), but still remained at a relatively high level. The ionic bond contents in the rice + starch group, 0.75% N-FB, and 0.2% CaCl2 groups decreased by 7.24, 4.04, and 2.11 g·L -1 , respectively. 0.75% EE-FB (40.00%) and 0.2% CaCl2 can significantly enhance the hydrophobic interactions and disulfide bonds of surimi gel, and the enhancing effect of 0.75% EE-FB (40.00%) is the most significant. The disulfide bond content in the N-FB (40.00%) group did not change significantly and the hydrophobic interaction decreased significantly; the hydrophobic interaction in the rice + starch group did not change significantly and the disulfide bond content decreased significantly. Ionic bonds are mainly used to stabilize the aggregation between proteins, and hydrophobic interactions and disulfide bonds are the main forces supporting the gel structure. Therefore, 0.75% EE-FB (40.00%) can optimize the structure of surimi gel protein to the greatest extent and promote the formation of its gel network. At the same time, the SEM results of the surimi gel protein in the 0.75% EE-FB (40.00%) group also proved that 0.75% EE-FB (40.00%) can make surimi form a dense gel network structure ( Figure 8 e), while there are some enlarged voids in the surimi gel after 0.75% N-FB (40.00%), which is consistent with the above results of surimi gel strength (Table 4) and water holding capacity ( Figure 3 ), indicating once again that submicron-nano scale fish bone powder is beneficial to the formation of gel network structure.

[0075] FT-IR determination of surimi gel

[0076] After freeze-drying the surimi gel samples of the NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group, 1 mg of the dried sample was mixed and ground with KBr and then pressed into a tablet. The FT-IR absorption spectrum range was 400 - 4000 cm -1 , the resolution was 2 cm -1 , and it was scanned 64 times. Deconvolution, second derivative, and Gaussian curve fitting were performed on the amide I band in the obtained spectrum to obtain the relative content changes of the protein secondary structure.

[0077] Compared with the NaCl surimi gel group, the α-helix and β-fold content in the secondary structure of surimi gel protein in the rice + starch group increased significantly ( Figure 7 ). The β-folding content of the three groups of surimi gels with the addition of 0.75% N-FB (40.00%), 0.2% CaCl2, and 0.75% EE-FB (40.00%) increased significantly by 0.30%, 2.06%, and 2.34%, respectively, among which the α-helix content of the 0.75% EE-FB (40.00%) group decreased significantly. It can be seen that EE-FB (40.00%) can maximize the increase of β-folding and reduce the effect of α-helix, thereby enhancing the strength of surimi gel.

[0078] SEM observation of surimi gel

[0079] The prepared surimi gel samples of NaCl group, rice + starch group, 0.75% N-FB (40.00%) group, 0.2% CaCl2 group, and 0.75% EE-FB (40.00%) group were cut into small pieces with a blade with a thickness of 1 mm, fixed with glutaraldehyde solution, washed with phosphate buffer, and sequentially dehydrated with ethanol, replaced with tert-butanol, freeze-dried, and gold-sprayed. The microstructure of the surimi gel was observed at an acceleration voltage of 3 kV and amplified 10,000 times.

[0080] Effects of NaCl, rice + starch, 0.75% N-FB (40.00%), 0.2% CaCl2, and 0.75% EE-FB (40.00%) on the microstructure of surimi gel Figure 8 As shown in the figure, the microstructure of the surimi in the NaCl group was porous and uneven, 0.75% EE-FB (40.00%) made the surimi form a dense gel network structure, while the surimi gel after 0.75% N-FB (40.00%) had some larger voids, which was consistent with the above-mentioned surimi gel strength (Table 3) and water holding capacity ( Figure 4 a) The results are consistent, which indicates that submicron-nanoscale fish bone powder is conducive to the formation of gel network structure.

[0081] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A hairtail fish mince gel containing tuna fish bones prepared by an extrusion puffing technique, characterized in that It includes the following raw materials. Calculated by mass percentage, the raw materials are as follows: Hairtail fish mince: 75.55%, NaCl: 2.5%, water: 21.95%, and the total weight of the three is 100%; The addition amount of EE-FB is 0.75% of the total weight of hairtail fish mince, NaCl and water; the tuna nano fish bone EE-FB prepared based on the extrusion puffing technology is prepared by the following method: 1) Cut the fish bones into small pieces about 5 cm long, blanch them in boiling water for 20 min, rinse them clean with tap water, dry them at 70 °C, and preliminarily crush the fish bones with a pulverizer; 2) Mix the preliminarily crushed fish bones, rice, and corn starch evenly, and process them with a single-screw extruder under the conditions of 130 °C and a rotation speed of 400 rpm. The obtained product is crushed again with a pulverizer to obtain EE-FB.

2. The cutlassfish surimi gel containing tuna fish bones prepared by an extrusion puffing technique according to claim 1, wherein In step 2), the weight percentage of the preliminarily crushed fish bones: rice: corn starch is 40.00%: 52.50%: 7.50%.

3. The preparation method of surimi gel containing tuna fish bones prepared by extrusion puffing technology according to claim 1, characterized in that It includes the following steps: 1) Frozen fish mince is thawed overnight at 4 °C, chopped and chopped for 2 min, and salted with NaCl and chopped for 2 min; 2) Add EE-FB, add ice water, adjust the moisture content, and chop for 3 min, and control the production temperature below 10 °C; 3) After the fish mince is enema-molded, it is gelatinized by the two-stage heating method, and stored at 4 °C after being cooled with ice water.

4. The preparation method of surimi gel containing tuna fish bones prepared by extrusion puffing technology according to claim 3, characterized in that The two-stage heating method in step 3) refers to heating at 40 °C for 30 min and heating at 90 °C for 20 min.

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