Method for unfreezing pseudosciaena crocea based on three-frequency orthogonal ultrasonic-assisted technology

Abstract

The invention discloses a method for unfreezing pseudosciaena crocea based on a three-frequency orthogonal ultrasonic-assisted technology. The method specifically comprises the following steps: S1, unfreezing frozen pseudosciaena crocea by using a three-frequency orthogonal ultrasonic-assisted unfreezing treatment group with the ultrasonic power of 220w; s2, in the thawing process, continuously monitoring and recording the temperature of the center of the sample in real time by using a T-shaped thermocouple; s3, when the temperature of the center of the pseudosciaena crocea sample rises to 4 + / -1 DEG C, unfreezing is completed, and the pseudosciaena crocea sample is taken out; and S4, dividing the experiment into five groups, namely a three-frequency orthogonal ultrasonic-assisted thawing treatment group with the ultrasonic power of 195W, an ultrasonic-assisted thawing treatment group with the ultrasonic power of 220W, an ultrasonic-assisted thawing treatment group with the ultrasonic power of 245W and the like. The three-frequency orthogonal ultrasonic-assisted thawing technology disclosed by the invention can improve the water holding capacity of the fish meat, effectively inhibit the lipid oxidation degree, reduce the aggregation degree of protein and reduce the denaturation degree of the protein.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic-assisted technology, and in particular to a method for thawing large yellow croaker based on three-frequency orthogonal ultrasonic-assisted technology. Background Technology

[0002] Ultrasound is a sound wave with frequencies exceeding human hearing, ranging from 20 kHz to 500 MHz. Depending on the application frequency, it can be divided into low-frequency ultrasound and high-frequency ultrasound. Low-frequency ultrasound has higher energy and is widely used in food processing and storage. Cavitation is the main physical mechanism by which ultrasound works in liquid media. Cavitation generally includes three stages: the formation, growth, and violent collapse of cavitation bubbles. When ultrasound is introduced into a container filled with liquid, tens of thousands of tiny bubbles, or cavitation bubbles, are generated due to the vibration of the liquid. These bubbles grow in the negative pressure zone created by the longitudinal propagation of ultrasound waves and rapidly collapse in the positive pressure zone, thus being compressed and stretched under alternating positive and negative pressures. At the moment the bubbles are compressed until they collapse, a huge instantaneous pressure is generated, typically reaching tens to hundreds of megapascals. When this collapse occurs near the solid surface, it generates microjets with specified pressure (100 MPa), temperature (5000 K), and velocity (400 km / s) characteristics, thereby increasing the mass transfer rate. Furthermore, ultrasound can also induce micro-stirring in liquids, thereby altering mass transfer.

[0003] Ultrasonic-assisted thawing is an emerging thawing technology that has been shown to reduce thawing time while maintaining the quality of frozen foods. The rapid thawing effect of ultrasonic-assisted thawing can be attributed to: (i) high-frequency oscillations caused by the attenuation of ultrasound waves in the medium, which are converted into heat energy; (ii) the use of ultrasound-induced microjets to enhance heat and mass transfer, thereby reducing heat and mass transfer resistance at the ice / liquid interface; and (iii) the vibrational energy provided by ultrasound waves being absorbed by the food during ultrasonic-assisted thawing. Ultrasonic absorption in the frozen portion of the food is much greater than in the thawing portion, especially at the junction of thawing and uncrywing areas. Only appropriate ultrasound power can improve the quality of thawed foods. Compared to single-frequency ultrasound devices, multi-frequency ultrasound devices can produce higher levels of mechanical disturbance and cavitation yield. Furthermore, the use of dual-frequency ultrasound enables a wider range of energy dissipation. Multi-frequency ultrasonic-assisted thawing technology has been shown to improve thawing speed, maintain the stability of myogenic fibers, and reduce lipid oxidation. However, high-power ultrasound can damage the tissue and protein structure of frozen foods. Summary of the Invention

[0004] This invention provides a method for thawing large yellow croaker based on three-frequency orthogonal ultrasound-assisted technology. The effects of three-frequency orthogonal ultrasound-assisted thawing technology on the quality characteristics of large yellow croaker, such as thawing loss, cooking loss, water holding capacity, LF-NMR, MRI, TBA, protein solubility, and surface hydrophobicity, are studied. The cavitation effect and mechanical vibration generated by ultrasound can accelerate the melting of ice crystals and improve the water holding capacity of fish meat. At the same time, it can effectively inhibit the degree of lipid oxidation and reduce the degree of protein aggregation and denaturation. Therefore, ultrasound-assisted technology is applied to the thawing process of large yellow croaker.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The three-frequency orthogonal ultrasound-assisted thawing method includes the following steps:

[0007] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0008] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0009] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed.

[0010] As a preferred embodiment, the large yellow croaker has a body length of approximately 35±5.0cm.

[0011] As a preferred embodiment, the body weight is approximately 500g ± 20g.

[0012] As a preferred embodiment, the victim was killed by striking the head with a heavy object before the experiment, then rinsed, vacuum-packed, and frozen.

[0013] The application of the above-mentioned three-frequency orthogonal ultrasound-assisted thawing method in fish thawing.

[0014] The method for thawing large yellow croaker based on three-frequency orthogonal ultrasound-assisted technology includes the following steps:

[0015] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0016] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0017] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0018] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0019] Beneficial effects: The three-frequency orthogonal ultrasound-assisted thawing technology of the present invention can improve the water-holding capacity of fish meat and effectively inhibit lipid oxidation, reduce protein aggregation and reduce protein denaturation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the thawing loss of each experimental group in Embodiment 1 of the present invention.

[0021] Figure 2 This is a schematic diagram of the water-holding capacity of each experimental group in Embodiment 2 of the present invention.

[0022] Figure 3 This is a schematic diagram of the cooking loss in each experimental group in Embodiment 3 of the present invention.

[0023] Figure 4 This is a schematic diagram of the transverse relaxation spectra of each experimental group in Embodiment 4 of the present invention.

[0024] Figure 5 This is a schematic diagram of nuclear magnetic resonance imaging of each experimental group in Embodiment 4 of the present invention.

[0025] Figure 6 This is a schematic diagram of the TBA content in each experimental group in Example 5 of the present invention.

[0026] Figure 7 This is a schematic diagram of protein solubility in each experimental group in Example 6 of the present invention.

[0027] Figure 8 This is a schematic diagram of the surface hydrophobicity of each experimental group in Embodiment 7 of the present invention.

[0028] Figure 9 This is a schematic diagram of the ultrasonic device of the present invention. Detailed Implementation

[0029] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0032] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0033] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0034] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0035] Other parameters are as follows: The large yellow croaker is about 35±5.0cm in length and about 500g±20g in weight. Before the experiment, it was killed by hitting its head with a heavy object, then rinsed, vacuum-packed and frozen.

[0036] Frozen large yellow croaker were subjected to different thawing treatments, followed by thawing loss measurements. Water loss during thawing and the stability of water content in the thawed samples can be reflected by thawing loss. Compared to the control group (FWT), the thawing loss of the TOUAT-treated groups was reduced, with the TOUAT-220W group showing the best performance (approximately 2.6%). This is because the cavitation effect and mechanical vibration generated by ultrasound accelerate ice crystal melting, reducing mechanical damage to muscle fibers from ice crystals during thawing, thereby reducing juice loss. Furthermore, TOUAT-220 ultrasound treatment further inhibited thawing loss by promoting uniform water migration and reducing local water accumulation. The results show that the 220W tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz) ultrasound-assisted thawing treatment group (TOUAT-220) can optimize thawing efficiency, maintain fish meat integrity, and improve the water-holding capacity of the fish meat. Figure 1 As shown.

[0037] Example 2

[0038] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0039] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0040] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0041] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0042] Other parameters are as follows: The large yellow croaker is about 35±5.0cm in length and about 500g±20g in weight. Before the experiment, it was killed by hitting its head with a heavy object, then rinsed, vacuum-packed and frozen.

[0043] Water-holding capacity reflects the water loss and remaining water stability in fish tissue after thawing. For example... Figure 2 As shown, TOUAT treatment significantly improved the water-holding capacity of fish meat. The water-holding capacity of the TOUAT-220 ultrasonic treatment group reached 80%, which was about 10% higher than that of the control group. The improvement in water-holding capacity is closely related to the myofibrillar protein structure and water distribution. Ultrasound enhances the binding ability of proteins to water molecules by disrupting the protein aggregation state and exposing more hydrophilic groups, thereby improving the water-holding capacity of fish meat. The results indicate that TOUAT-220 has a positive effect on improving the water-holding capacity of large yellow croaker.

[0044] Example 3

[0045] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0046] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0047] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0048] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0049] Other parameters are as follows: The large yellow croaker is about 35±5.0cm in length and about 500g±20g in weight. Before the experiment, it was killed by hitting its head with a heavy object, then rinsed, vacuum-packed and frozen.

[0050] Cooking loss reflects the loss of water in fish tissue after thawing and the stability of the remaining water content. For example... Figure 3 As shown, cooking loss decreased with increasing ultrasonic power, with the TOUAT-220 treatment group exhibiting the lowest loss (approximately 11%), significantly lower than the control group (17%). TOUAT-220 treatment may reduce water and soluble substance loss during cooking by inhibiting the oxidative aggregation of myofibrillar proteins and maintaining the stability of their network structure. Furthermore, the ultrasound-induced microfluidic effect promotes protein molecule unfolding and re-crosslinking, enhancing thermal stability and further reducing cooking loss. The results indicate that TOUAT-220 has a positive effect on improving the water-holding capacity of large yellow croaker. In this example, a 220W tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz) ultrasound-assisted technique was used for the thawing process of frozen large yellow croaker.

[0051] Example 4

[0052] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0053] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0054] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0055] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0056] Other parameters are as follows: The large yellow croaker is about 35±5.0cm in length and about 500g±20g in weight. Before the experiment, it was killed by hitting its head with a heavy object, then rinsed, vacuum-packed and frozen.

[0057] LF-NMR reflects the state of water distribution in a sample, where T22 represents the fixed water content. The T22 peak is highest in the 220W ultrasound-assisted thawing group (TOUAT-220), and then significantly shortens with increasing ultrasound power. This indicates that ultrasound treatment alters the water distribution. The higher T22 peak reflects tighter binding of water to myofibril proteins and reduced fluidity, consistent with the structure of water-holding capacity. The mechanical energy generated by ultrasound promotes the redistribution of water between muscle fibers, reducing the damage to cell structure caused by large ice crystal formation, thereby maintaining water binding capacity. Furthermore, MRI images show that the water distribution in the TOUAT-220 ultrasound-treated group is more uniform, with reduced local water accumulation, further validating the optimizing effect of ultrasound treatment on water migration. The ultrasound-induced microfluidic effect can disrupt protein aggregation, exposing more hydrophilic groups and enhancing their binding ability to water molecules, thereby increasing the proportion of bound water. Simultaneously, the uniform water distribution shown on MRI is due to the unblocking effect of ultrasound on water channels between muscle fibers, reducing local tissue collapse caused by ice crystal compression. The results showed that the 220W tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz) ultrasound-assisted thawing treatment group (TOUAT-220) could accelerate thawing while maintaining the dynamic balance of water and protein. Figure 4 , 5 As shown.

[0058] Example 5

[0059] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0060] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0061] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0062] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0063] Other parameters are as follows: The large yellow croaker is about 35±5.0cm in length and about 500g±20g in weight. Before the experiment, it was killed by hitting its head with a heavy object, then rinsed, vacuum-packed and frozen.

[0064] TBA (Total Bioassay) assesses the degree of lipid oxidation in fish by detecting secondary oxidation products. TOUAT-220 treatment significantly reduced the TBA value in large yellow croaker (P<0.05). The TBA value of the control group (FWT) was 0.17 mg MDA / kg, while the TBA value of the ultrasound-assisted thawing group (TOUAT-220) with a 220W tri-frequency orthogonal (horizontal 20, 28 kHz + vertical 40 kHz) was reduced to 0.12 mg MDA / kg, indicating that ultrasound-assisted thawing effectively inhibited lipid oxidation. The cavitation effect of ultrasound reduces the accumulation of secondary oxidation products such as malondialdehyde (MDA) by disrupting the free radical generation pathway in the oxidation chain reaction. Furthermore, high-frequency vibration accelerates the diffusion of antioxidant components (such as endogenous enzymes) in the thawing medium, further delaying the oxidation process. This result is closely related to the increased protein solubility and changes in surface hydrophobicity, indicating that ultrasound treatment indirectly inhibits lipid oxidation by protecting protein structure. The results showed that ultrasound-assisted thawing treatment (TOUAT-220) with a tri-frequency orthogonal (horizontal 20, 28 kHz + vertical 40 kHz) power of 220 W effectively inhibited lipid oxidation. Figure 6 As shown.

[0065] Example 6

[0066] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0067] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0068] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0069] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0070] Other parameters are as follows: The large yellow croaker is about 35±5.0cm in length and about 500g±20g in weight. Before the experiment, it was killed by hitting its head with a heavy object, then rinsed, vacuum-packed and frozen.

[0071] TOUAT-220 sonication significantly improved the solubility of myofibrillar proteins (P<0.05). The solubility of the control group (FWT) was 60%, while that of the TOUAT-220-treated group increased to 68%. This indicates that the mechanical shearing effect of ultrasound disrupts protein aggregates and promotes the dispersion of myofibrillar protein monomers. Simultaneously, the ultrasound-induced microfluidic effect weakens hydrophobic interactions and hydrogen bonds, reducing the formation of insoluble aggregates. The results show that TOUAT-220 sonication exposes the hydrophilic groups of proteins, enhancing their ability to bind to water molecules, thereby improving solubility. The equilibrium effect of TOUAT-220 sonication was the most significant. This result is consistent with the increased water-holding capacity and decreased TBA value, indicating that TOUAT-220 sonication optimizes protein functional properties at the molecular level, such as… Figure 7 As shown.

[0072] Example 7

[0073] Step S1: The frozen large yellow croaker was thawed using an ultrasonic-assisted thawing treatment group with an ultrasonic power of 220W and three orthogonal frequencies (horizontal 20, 28kHz + vertical 40kHz).

[0074] Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time;

[0075] Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed (TOUAT-220).

[0076] Step S4: The experiment was divided into five groups: a 195W ultrasonic-assisted thawing group (TOUAT-195) with tri-frequency orthogonal (horizontal 20, 28kHz + vertical 40kHz), a 220W ultrasonic-assisted thawing group (TOUAT-220), a 245W ultrasonic-assisted thawing group (TOUAT-245), a 270W ultrasonic-assisted thawing group (TOUAT-270), and a control group without ultrasonic treatment (running water thawing FWT).

[0077] TOUAT-220 treatment significantly reduced the surface hydrophobicity of myofibrillar proteins (P<0.05). The surface hydrophobicity of the control group (FWT) was much higher than that of the TOUAT-200-treated group, indicating that ultrasound induced the exposure of hydrophobic groups inside the protein. This is related to ultrasound disrupting the protein structure, leading to molecular unfolding. Enhanced hydrophobicity is usually associated with improved protein functional properties (such as emulsification). The results show that TOUAT-220 can balance hydrophobic group exposure and protein stability. In summary, TOUAT-220 treatment improves functionality while maintaining protein structural stability, such as… Figure 8 As shown.

[0078] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A three-frequency orthogonal ultrasound-assisted thawing method, characterized in that, Specifically, the steps include the following: Step S1: The frozen large yellow croaker was thawed using a three-frequency orthogonal ultrasound-assisted thawing treatment group with an ultrasonic power of 220W. Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time; Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, the thawing is complete, and the sample is removed.

2. The three-frequency orthogonal ultrasound-assisted thawing method according to claim 1, characterized in that, The large yellow croaker is about 35±5.0cm in length.

3. The three-frequency orthogonal ultrasound-assisted thawing method according to claim 1, characterized in that, Body weight is approximately 500g ± 20g.

4. The three-frequency orthogonal ultrasound-assisted thawing method according to claim 1, characterized in that, Before the experiment, the victims were struck on the head with a heavy object to kill them. They were then rinsed, vacuum-packed, and frozen.

5. Application of the above-mentioned three-frequency orthogonal ultrasound-assisted thawing method in fish thawing.

6. A method for thawing large yellow croaker based on three-frequency orthogonal ultrasound-assisted technology, characterized in that, Specifically, the steps include the following: Step S1: The frozen large yellow croaker was thawed using a three-frequency orthogonal ultrasound-assisted thawing treatment group with an ultrasonic power of 220W. Step S2: During the thawing process, use a T-type thermocouple to continuously monitor and record the temperature at the center of the sample in real time; Step S3: When the temperature at the center of the large yellow croaker sample rises to 4±1℃, thawing is complete, and the sample is removed. Step S4: The experiment was divided into five groups: a 195W tri-frequency orthogonal ultrasound-assisted thawing treatment group, a 220W ultrasound-assisted thawing treatment group, a 245W ultrasound-assisted thawing treatment group, a 270W ultrasound-assisted thawing treatment group, and a control group without ultrasound treatment.

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