Squid salad processing method based on gradient temperature curing

Abstract

This invention relates to the field of aquatic product deep processing technology, and discloses a squid salad processing method based on gradient temperature cooking. The squid salad is made from cooked squid rings, mixed vegetables, and a salad dressing containing a specific compound emulsifying stabilizer. The processing method includes: subjecting pre-treated squid to acoustic-thermal coupled gradient cooking, sequentially undergoing three stages: ultrasonic-assisted low-temperature sol-gelation, silent medium-temperature heat-induced gelation, and high-temperature safe setting; subsequently, immediately immersing it in an ice-water mixture for gradient heat-blocking cooling, draining, and then mixing with the dressing. This invention effectively solves the problems of severe moisture loss and tough texture in traditional processes by precisely controlling the timing of ultrasonic intervention and three-stage temperature control, combined with the heat shock effect, giving the product a crispy exterior and tender interior texture. Simultaneously, the use of compound stabilizers improves the emulsification stability and water-holding capacity of the dressing in a high-humidity matrix, increasing the yield of the finished product.

Description

Technical Field

[0001] This invention relates to the field of deep processing technology for aquatic products, specifically a squid salad processing method based on gradient temperature cooking. Background Technology

[0002] Squid, a cephalopod aquatic product that is high in protein and low in fat, has muscle tissue mainly composed of dense myofibril protein and low connective tissue content. In the development of salad-style cold dishes using squid, the cooking process and sauce preparation are two key aspects that determine the final product quality.

[0003] Existing squid cooking processes mostly employ high-temperature boiling or atmospheric pressure steam heating. Because squid muscle fibers are extremely sensitive to heat, under continuous high-temperature heat, myosin and actin undergo violent denaturation and contraction, causing a large amount of water to be squeezed out from within the muscle fiber network. This drastic dehydration effect not only reduces the product yield but also causes the muscle tissue to shrink and harden, ultimately resulting in a dry, tough texture with high chewing resistance, making it difficult to balance cooking safety and tenderness. Furthermore, simple heat conduction heating methods are insufficient to achieve orderly protein gelation and cannot construct a three-dimensional gel network that effectively retains water.

[0004] In terms of the cooling process, traditional processing typically involves natural cooling or cooling with running water at room temperature after heating. Due to the thermal inertia within biological tissues, the core temperature cannot drop rapidly in a short time, causing residual heat to continue acting on the proteins, leading to excessive denaturation. This slow cooling process fails to form a dense, contractile layer on the surface of the squid, resulting in a product that lacks the crisp texture characteristic of cold salads, leading to an overall texture that is either soft or tough, lacking depth and dimension.

[0005] In the formulation of dressings, salad products require dressings with good coating properties and stability. However, cooked squid typically contains high levels of moisture on its surface and inside. During mixing with dressings and subsequent refrigeration, moisture migration can disrupt the original emulsion balance of the dressing. Conventional salad dressings, upon contact with a high-moisture matrix, are prone to oil-water interface film rupture, leading to aggregation and stratification. This results in water separation and dilution of the dressing, affecting not only the product's appearance but also accelerating the loss of flavor compounds and the growth of microorganisms, thus limiting the shelf-life stability of prepared foods. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a squid salad processing method based on gradient temperature cooking, which solves the problems of low cooking yield, tough and chewy meat, and easy separation and stratification of salad dressing when it comes into contact with a moist substrate in existing squid salad processing.

[0007] To achieve the above objectives, the present invention provides the following technical solution: Firstly, the present invention provides a squid salad processing method based on gradient temperature cooking, employing the following technical solution: A method for processing squid salad based on gradient temperature cooking includes the following steps: S1. Raw material pretreatment: Cut the thawed squid into pieces, soak them in the seasoning solution, and drain. S2, Acoustic-thermal coupling gradient ripening: (1) Acoustic-thermal synergistic zone: Immerse the squid in a medium at 53-57°C and simultaneously turn on ultrasonic-assisted treatment for 10-15 minutes. The medium is the conditioning liquid described in step S1. (2) Heat field dominance zone: Place the squid in a medium of 73-77℃, turn off the ultrasonic waves, and let it stand to cook for 5-8 minutes; (3) Safety barrier zone: Place the squid in a medium at 90-95℃ and heat for 60-90 seconds; S3, Gradient thermal blockade: After step S2, immediately immerse the squid in a mixture of ice and water at 0-4℃ to cool until the core temperature drops below 10℃, then drain to obtain cooked squid rings; S4. Mixing: Mix the cooked squid rings, mixed vegetables and salad dressing evenly to get the mixed squid salad; The salad dressing is made from the following components by weight percentage: 35%-40% vegetable oil, 20%-25% water, 8%-10% flavoring acid, 10%-12% pasteurized egg yolk liquid, 5%-8% white sugar, 1%-1.5% edible salt, and 0.8%-1.2% compound emulsifying stabilizer, with the remainder being seasoning ingredients and water.

[0008] By employing the above technical solutions, and utilizing the synergistic effects of acoustic-thermal coupling gradient ripening, gradient thermal blocking technology, and a specific emulsification system, precise control of squid texture and stability of the product system were achieved. The specific physicochemical mechanisms are as follows: Staged protein structure regulation: Acoustothermal synergistic sol-gelation: In the temperature range of 53-57℃, myosin is in the early stage of thermal sol-gelation. The cavitation effect and microjets generated by ultrasound are introduced to disrupt the quaternary structure of myofibrils, break some non-covalent bonds, and promote the dissociation of the myosin head from the thick filaments and its moderate unfolding, exposing more reactive sites and enhancing the protein's hydration capacity.

[0009] Silent thermally induced gelation: In the temperature range of 73-77℃, the unfolded protein molecules begin to cross-link and form a gel network. Turning off the ultrasound at this stage is crucial because the gel network formed at this stage is still unstable; violent mechanical vibrations can disrupt the connections between network nodes, leading to a loose structure and decreased water-holding capacity. The static thermal field ensures the orderly construction of the three-dimensional gel network and the fixation of water.

[0010] High-temperature setting and sterilization: Short-term heating in the 90-95℃ temperature range completes the final protein denaturation and setting, and achieves food-grade sterilization, while avoiding excessive dehydration caused by prolonged high temperature.

[0011] Heat shock surface modification: After high-temperature cooking, the squid is immediately placed in a 0-4℃ environment. This significant temperature difference creates a heat shock effect on the surface of the squid. The surface muscle fibers instantly contract and densify, forming a highly dense physical barrier that effectively locks in the internal juices and gives the product an outer crispness. At the same time, the heat in the center is rapidly removed, preventing the continuous denaturation of internal proteins due to thermal inertia and maintaining the tenderness of the internal meat.

[0012] Construction of high-strength interfacial membranes: For cooked squid matrices with high water activity, conventional sauces are prone to oil-water interface instability. The sauce in this solution, through specific composite components, forms an adsorption layer with high viscoelastic modulus at the oil-water interface and constructs a continuous three-dimensional network structure, which can resist osmotic pressure changes caused by water migration and prevent the sauce from demulsifying and separating.

[0013] Preferably, the composite emulsifying stabilizer comprises the following components in parts by weight: 40-50 parts modified corn starch, 15-20 parts xanthan gum, 10-15 parts guar gum, 15-20 parts soy protein isolate, and 5-10 parts dispersion carrier. More preferably, the modified corn starch is acetylated distarch phosphate; and the dispersion carrier is maltodextrin. By employing the above technical solution, a multi-layered stable colloidal network is constructed: Steric hindrance effect: Soy protein isolate acts as a surfactant adsorbed onto the surface of oil droplets, xanthan gum and guar gum synergistically increase the viscosity of the aqueous phase, and modified starch granules fill the continuous phase. This multiphase distribution creates strong steric hindrance, restricting the Brownian motion and aggregation of oil droplets.

[0014] Moisture migration blocking: Acetylated distarch phosphate has excellent freeze-thaw stability and water retention. Combined with the network structure of hydrophilic colloids, it can effectively bind free water in the system and prevent external (squid surface) water from penetrating into the sauce, thereby maintaining the kinetic stability of the emulsion system.

[0015] Preferably, the composite emulsifying stabilizer is prepared by the following method: The powdered components are placed in a mixer and mixed at 18-22 rpm for 15-20 minutes at a temperature of 20-25°C and a relative humidity of <40%, until the CV value of the mixing uniformity is less than 5%, and then passed through an 80-mesh sieve. By adopting the above technical solution, physical mixing is carried out under mild conditions of low shear and low humidity, preventing the hydrophilic colloids from absorbing moisture and clumping, as well as the denaturation of heat-sensitive proteins. This ensures that each component is uniformly distributed in a microscopic dispersion state, allowing for simultaneous dissolution and synergistic effects during subsequent hydration.

[0016] Preferably, in step S1, the thickness or width of the cut squid is controlled between 0.8cm and 1.2cm; the conditioning solution consists of the following components by mass percentage: sodium chloride 0.8%-1.2%, sodium citrate 0.2%-0.3%, sodium bicarbonate 0.05%-0.1%, with the remainder being water; the pH of the conditioning solution is adjusted to 7.2-7.5; and the material-to-liquid ratio during soaking is 1:2 to 1:3. By adopting the above technical solution, adjusting the pH of the system to be slightly alkaline and introducing salts with specific ionic strength causes the myofibrillar protein lattice structure to expand due to electrostatic repulsion, increasing the swelling degree of the muscle fibers and providing a structural basis for moisture retention during the subsequent acoustic and thermal curing process.

[0017] Preferably, in the acoustic-thermal synergy zone stage of step S2, the frequency of the ultrasonic wave is controlled at 28kHz-40kHz, and the power density is controlled at 0.3-0.5W / cm². 2 The operating mode is continuous wave mode. By adopting the above technical solution, low-frequency ultrasound is selected mainly to utilize its strong cavitation physical effect rather than thermal effect, which can effectively penetrate the myofibril membrane and promote the dissolution of myosin without causing protein denaturation due to local overheating.

[0018] Preferably, in step S3, "immediately" means within 5 seconds after the end of step S2; the cooling time is 8-12 minutes; after draining, centrifugal dehydration is used to remove surface water, with a centrifugal speed of 800-1000 rpm. By adopting the above technical solution, the time lag of heat blocking intervention is strictly controlled, eliminating the influence of thermal inertia; appropriate centrifugal dehydration removes surface free water to facilitate sauce adhesion while avoiding damage to internal bound water, maintaining the juiciness of the product.

[0019] Preferably, in step S4, the salad dressing is prepared as follows: (1) Aqueous phase dissolution: Mix water, flavoring acid solution, white sugar, edible salt, egg yolk liquid and compound emulsifying stabilizer, and hydrate by stirring at low speed; (2) High shear emulsification: Turn on the high shear emulsifier and set the speed to 10,000-12,000 rpm; (3) Oil phase addition: Under shear conditions, slowly add vegetable oil in thin threads to the aqueous phase over 5-8 minutes; (4) Homogenization: Continue shearing for 2-3 minutes to form a semi-solid sauce. By adopting the above technical solution, the oil phase is dispersed into micron-sized droplets by high shear force, which promotes the rapid adsorption of the composite emulsifying stabilizer at the newly formed oil-water interface, forming a dense and elastic interfacial film to prevent droplet aggregation.

[0020] Preferably, in step S1, if the selected squid raw material is Peruvian stem squid with thicker flesh, the processing time in the acoustic-thermal synergistic zone stage of step S2 is extended to 15-18 minutes, and the ultrasonic frequency is 25-30kHz. By adopting the above technical solution, considering the characteristics of Peruvian stem squid's large muscle fibers and dense connective tissue, a lower frequency (25-30kHz) with deeper penetration and extended treatment time are used to ensure that the physical field energy can penetrate deep into the muscle center, achieving uniform tenderization.

[0021] Preferably, in step S4, the weight ratio of the cooked squid rings, mixed vegetables, and salad dressing is: 50-60 parts cooked squid rings, 25-30 parts mixed vegetables, and 15-20 parts salad dressing. Following step S4, the process further includes: quantitatively modifying atmosphere packaging the prepared squid salad and immediately storing it in a cold storage at 0-4°C. By adopting the above technical solution, this specific ratio achieves optimal rheological matching of the solid and liquid phases, ensuring that the sauce can completely coat the ingredients with an appropriate thickness to form a physical protective film, preventing matrix dehydration or sauce separation. Combined with the low-oxygen, antibacterial microenvironment created by modified atmosphere packaging and low-temperature refrigeration, it effectively synergistically blocks the lipid oxidation chain reaction, inhibits microbial growth and enzyme activity, thereby extending shelf life while maintaining the sensory quality of the product.

[0022] This invention provides a method for processing squid salad based on gradient temperature cooking. It has the following beneficial effects: 1. This invention solves the problems of severe muscle fiber contraction and moisture loss caused by traditional high-temperature cooking by constructing a three-stage gradient process that combines ultrasound-assisted low-temperature sol-gelation, silent medium-temperature core maturation, and high-temperature instantaneous setting. The first stage utilizes the ultrasonic cavitation effect to promote the dissolution and unfolding of myosin; the second stage uses a silent thermal field to avoid mechanical vibration damaging the formed gel network; and the third stage rapidly sterilizes and sets the gel. While ensuring food safety, this process maximizes the retention of internal moisture in the squid, reduces the shear force of the finished product, and significantly increases the yield compared to traditional processes.

[0023] 2. This invention employs gradient heat-blocking technology, introducing an ice-water quenching step immediately after high-temperature cooking. The significant temperature difference generates a heat shock effect, rapidly terminating the continued denaturation of proteins by residual heat and preventing meat aging. Simultaneously, it causes the squid's surface muscle fibers to contract and densify instantly, locking in internal juices. This treatment imparts excellent surface crispness and internal juiciness to the finished salad, overcoming the shortcomings of traditional natural cooling processes that result in a soft or dry texture.

[0024] 3. This invention prepares a specialized composite emulsifying stabilizer by compounding modified starch, hydrocolloids (xanthan gum, guar gum), and soy protein isolate. Utilizing the synergistic effect among the components, a high-strength emulsifying interfacial film and a three-dimensional network structure are constructed, enhancing the water-holding capacity and coating ability of the sauce. Even after mixing with moist cooked squid and vegetables, the sauce maintains a uniform and stable semi-solid state, effectively preventing oil-water separation and ensuring the sensory quality and shelf-life stability of the product. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Preparation Examples 1-3: Preparation Example 1: This preparation example provides a composite emulsifying stabilizer in which the proportions of each component are in the middle of the preferred range, thereby achieving optimal emulsifying stability and suitable mouthfeel viscosity.

[0027] The specific formula consists of: 45 parts acetylated distarch phosphate, 17.5 parts xanthan gum, 12.5 parts guar gum, 18 parts soy protein isolate (SPI), and 7 parts maltodextrin.

[0028] The preparation method is as follows: First, accurately weigh the raw material powders as specified above. Second, add the weighed raw materials into a V-type mixer all at once, controlling the workshop ambient temperature at 22℃ and the relative humidity at 35%. Start the mixer, set the speed to 20 rpm, and the mixing time to 18 minutes. Finally, sieve the mixed powder through an 80-mesh stainless steel standard sieve to remove any possible small lumps, collect the sieve-passing material, and obtain a grayish-white, free-flowing composite emulsion stabilizer powder, which is then sealed and packaged for later use.

[0029] Preparation Example 2: This preparation example provides a composite emulsifying stabilizer, which is suitable for applications requiring high coating ability.

[0030] The specific formula consists of: 40 parts acetylated distarch phosphate, 20 parts xanthan gum, 15 parts guar gum, 15 parts soy protein isolate, and 10 parts maltodextrin.

[0031] The preparation method is as follows: First, accurately weigh the raw material powders as specified above. Second, put the raw materials into a multi-dimensional motion mixer and mix for 20 minutes at 22 rpm under normal temperature and low humidity conditions (temperature 25℃, humidity <40%) to ensure that the high proportion of colloids is evenly dispersed with other components. Finally, pass the mixture through an 80-mesh sieve, collect the finished product, and seal it for storage.

[0032] Preparation Example 3: This preparation example provides a composite emulsifying stabilizer, which is suitable for situations where a refreshing taste is desired and excessive thickening is avoided.

[0033] The specific formula consists of: 50 parts acetylated distarch phosphate, 15 parts xanthan gum, 10 parts guar gum, 20 parts soy protein isolate, and 5 parts maltodextrin.

[0034] The preparation method is as follows: First, accurately weigh the raw material powders as specified above. Second, put the raw materials into a V-type mixer and mix for 15 minutes at 18 rpm under an environment of 20°C and 30% relative humidity. Finally, pass the mixture through an 80-mesh sieve to remove impurities and lumps, obtaining the finished powder, which is then sealed for later use.

[0035] Examples 1-4: Example 1: This embodiment uses Argentine squid as raw material, combined with the composite emulsifying stabilizer obtained in Example 1, and includes the following steps: S1. Raw Material Pretreatment and Preparation of Conditioning Solution: Select frozen Argentine squid, thaw under running water to a core temperature of -1℃, remove the viscera and skin, and cut into squid rings approximately 1.0cm wide. Prepare the conditioning solution (by weight percentage): sodium chloride 1.0%, sodium citrate 0.25%, sodium bicarbonate 0.08%, with the remainder being water, and adjust the pH to 7.4. Immerse the squid rings in the conditioning solution at a ratio of 1:2.5, soak for 18 minutes, and then drain.

[0036] S2, Acoustic-thermal coupling gradient ripening: (1) Acoustic-thermal synergy zone: The squid rings were immersed in a conditioning liquid medium at 55°C (ultrasonic constant temperature water bath), and the ultrasonic waves were turned on at a frequency of 40kHz and a power density of 0.4W / cm³. 2 Continuous wave mode processing for 12 minutes; (2) Hot zone: Quickly transfer to a medium at 75°C, turn off the ultrasonic waves, and let it ripen silently for 6 minutes; (3) Safety barrier zone: Quickly transfer to a medium at 95°C and heat for 75 seconds.

[0037] S3, Gradient Thermal Blocking: After step S2, immediately immerse the squid in a 2°C ice-water mixture within 3 seconds and cool for 8 minutes until the core temperature drops below 10°C. After draining, centrifuge at 900 rpm for 45 seconds to remove water.

[0038] S4. Mixing and Packaging: By weight, take 55 parts of cooked squid rings, 28 parts of mixed vegetables (including shredded red and yellow bell peppers and onions, rinsed with 1% salt water), and 17 parts of the salad dressing prepared above. Gently mix evenly at 12°C, pack in a controlled atmosphere package, and immediately store in a 0-4°C cold storage.

[0039] Example 2: This embodiment aims to verify the technical feasibility under low temperature and low frequency conditions, and in conjunction with the composite emulsion stabilizer obtained in Example 3, includes the following steps: Preparation of salad dressing: By weight percentage, take 35% vegetable oil, 25% water, 8% flavoring acid solution, 10% pasteurized egg yolk liquid, 5% white sugar, 1% edible salt, 1.2% of the compound emulsifying stabilizer of Preparation Example 3, and the remainder is auxiliary materials. The preparation process is the same as in Example 1.

[0040] Squid salad preparation steps: S1. Raw material pretreatment: Argentine squid is cut into 0.8cm wide squid rings. Preparation solution: Sodium chloride 0.8%, sodium citrate 0.2%, sodium bicarbonate 0.05%, pH adjusted to 7.2. Material-to-liquid ratio 1:2, soak for 15 minutes and drain.

[0041] S2, Acoustic-thermal coupling gradient ripening: (1) Acoustic-thermal synergy zone: temperature 53℃, ultrasonic frequency 28kHz (emphasizing physical cavitation), power density 0.3W / cm³ 2 Processing time: 10 minutes; (2) Hot zone: Temperature 73℃, turn off the ultrasonic waves, let it stand for 5 minutes to mature; (3) Safety barrier zone: temperature 90℃, heating for 60 seconds.

[0042] S3, Gradient thermal blockage: Immediately immerse in a 0°C ice-water mixture, cool for 8 minutes, drain, and centrifuge to remove water (800 rpm).

[0043] S4. Mixing and Packaging: By weight, take 60 parts of cooked squid rings, 25 parts of mixed vegetables, and 15 parts of salad dressing and mix well. Pack and refrigerate as in Example 1.

[0044] Example 3: This embodiment aims to verify the process stability under higher temperatures and energy inputs, and in conjunction with the composite emulsion stabilizer obtained in Example 2, includes the following steps: Preparation of salad dressing: By weight percentage, take 40% vegetable oil, 20% water, 10% flavoring acid solution, 12% pasteurized egg yolk solution, 8% white sugar, 1.5% edible salt, 0.8% of the compound emulsifying stabilizer from Example 2, and the remainder as auxiliary materials. The preparation process is the same as in Example 1.

[0045] Squid salad preparation steps: S1. Raw material pretreatment: Argentine squid is cut into 1.2cm wide squid rings. Preparation solution: Sodium chloride 1.2%, sodium citrate 0.3%, sodium bicarbonate 0.1%, pH adjusted to 7.5. Material-to-liquid ratio 1:3, soak for 20 minutes and drain.

[0046] S2, Acoustic-thermal coupling gradient ripening: (1) Acoustic-thermal synergy zone: temperature 57℃, ultrasonic frequency 40kHz, power density 0.5W / cm² 2 Processing time: 15 minutes; (2) Heat field dominant zone: temperature 77℃, turn off ultrasonic waves, let stand and mature for 8 minutes; (3) Safety barrier zone: temperature 95℃, heating for 90 seconds.

[0047] S3, Gradient thermal blockade: Immediately immerse in 4°C ice water, cool for 12 minutes, drain, and centrifuge to remove water (1000 rpm).

[0048] S4. Mixing and Packaging: By weight, take 50 parts of cooked squid rings, 30 parts of mixed vegetables, and 20 parts of salad dressing and mix well. Pack and refrigerate as in Example 1.

[0049] Example 4: This embodiment aims to demonstrate the adaptability of the method to different varieties of squid with thicker flesh. The raw material is changed to Peruvian squid, and the composite emulsifying stabilizer obtained in Preparation Example 1 is used. The method includes the following steps: Preparation of salad dressing: The formula and preparation process are exactly the same as in Example 1.

[0050] Squid salad preparation steps: S1. Raw material pretreatment: Select Peruvian squid, thaw and skin it, and cut it into squid pieces approximately 1.2-1.5 cm thick. The preparation solution formula is the same as in Example 1. The soaking time is extended to 25 minutes.

[0051] S2, Acoustic-thermal coupling gradient ripening: (1) Acoustic-thermal synergy zone: temperature 55℃. Turn on ultrasonic waves, frequency 28kHz (stronger penetration), power density 0.5W / cm³. 2The processing time has been extended to 18 minutes; (2) Hot zone: Temperature 75℃, turn off the ultrasonic waves, let it stand and mature for 10 minutes; (3) Safety barrier zone: temperature 95℃, heating for 90 seconds.

[0052] S3, Gradient thermal blockade: Immediately immerse in a 0-2℃ ice-water mixture, cool for 15 minutes to ensure the core temperature drops below 10℃, then centrifuge to dehydrate.

[0053] S4. Mixing and Packaging: By weight, take 55 parts of cooked squid pieces, 28 parts of mixed vegetables, and 17 parts of salad dressing and mix well. Pack and refrigerate as in Example 1.

[0054] Comparative Examples 1-5: Comparative Example 1: Compared with Example 1, the difference is that this comparative example does not use the acoustic-thermal coupling and gradient temperature cooking process. The specific operation is as follows: the pre-treated squid rings are directly put into boiling water at 100°C and cooked for 2 minutes until fully cooked. After being taken out, they are naturally cooled at room temperature. The remaining raw material processing and subsequent mixing steps are the same as in Example 1.

[0055] Comparative Example 2: Compared with Example 1, the difference is that the ultrasonic generator was not turned on throughout the process. That is, during the first stage (55°C) heating process, only static water bath heat conduction was used for treatment, and no 40kHz ultrasonic wave was applied. The remaining temperature gradient, time parameters and operating steps were the same as in Example 1.

[0056] Comparative Example 3: Compared to Example 1, the difference lies in that the ultrasonic treatment time covers both the first and second stages. Specifically, when entering the second stage (75°C) of core curing, the ultrasonic generator was not turned off, but continued to operate at 40kHz and 0.4W / cm². 2 The ultrasonic radiation continues until the end of this stage, only being turned off during the high temperature of the third stage. All other parameters are the same as in Example 1.

[0057] Comparative Example 4: Compared with Example 1, the difference is that the second stage (75°C) medium-temperature core curing step is omitted. Specifically, after the first stage (55°C) ultrasonic-assisted treatment, the squid rings are directly and quickly transferred to the third stage (95°C) high-temperature water bath for 2 minutes of heating, and the remaining steps are the same as in Example 1.

[0058] Comparative Example 5: Compared with Example 1, the difference lies in the cooling method. Specifically, after the third stage of maturation, the squid rings are removed and drained, and then allowed to cool naturally at room temperature (25°C) until the core temperature reaches the target. The rapid cooling step using a 0-4°C ice-water mixture is omitted, while the rest is the same as in Example 1.

[0059] Test Example 1-2: Test Example 1: Physicochemical Indicators and Objective Data Testing Experimental materials: The samples to be tested were squid rings from Examples 1-4 and Comparative Examples 1-5 that had undergone complete processing, drained and cooled to 4°C.

[0060] Test method: Finished product yield: Weigh the fresh squid precisely and record the weight as follows: After undergoing the appropriate ripening, cooling, and draining processes (to remove surface free water), it is weighed accurately again and recorded as follows. Calculation formula: This indicator reflects the ability of the muscle fiber network to retain internal moisture during processing.

[0061] Shear force measurement: Measured using a TA.XTPlus texture analyzer. Probe model: HDP / BS (Warner-Bratzler BladeSet). Parameter settings: Pre-measurement speed 2.0 mm / s, test speed 1.0 mm / s, post-measurement speed 10.0 mm / s, trigger force 5 g. Procedure: Select a section of sample with uniform thickness and place the squid muscle fiber direction perpendicular to the blade movement direction. Record the maximum peak force (g) required for the probe to cut the sample. Each sample was measured in parallel 10 times, and the maximum and minimum values ​​were discarded before taking the average. This index directly characterizes the tenderness of the meat; the lower the value, the more tender the meat. However, it needs to be combined with centrifugal water loss rate to determine whether the softness is due to structural disintegration.

[0062] Centrifugal water loss rate: Take approximately 5.0g of the chopped sample and record it as follows: Wrap the sample in filter paper and place it in a centrifuge tube. Centrifuge at 4000 rpm for 15 minutes at 4°C. Remove the sample and weigh it again, recording the weight as follows. Calculation formula: This index is used to characterize the stability of protein gel networks. A higher value indicates a weaker ability of the gel network to bind water, or that the network structure has been damaged.

[0063] Test results: The physicochemical test data of each group of samples are shown in Table 1. Table 1. Summary of physicochemical properties of each example and comparative sample Results Analysis and Conclusions: Based on the data in Table 1 and the acoustic-thermal coupling gradient ripening mechanism of this invention, the following analytical conclusions are drawn: The promoting effect of acoustic-thermal coupling on gel network construction: Comparing Example 1 and Comparative Example 2, under the same temperature gradient, the introduction of ultrasound assistance (Example 1) increased the yield by approximately 11.8% and reduced the centrifugal water loss rate by approximately 50%. This indicates that the introduction of low-frequency ultrasound in the first stage (55°C) effectively disrupted the myosin aggregates using the microjets generated by the cavitation effect, promoting their dissolution and unfolding from the myofibrils, forming a denser gel network with strong water-holding capacity. Comparative Example 2 lacked physical field assistance and relied solely on thermal diffusion, resulting in uneven gelation and relatively greater water loss.

[0064] The criticality of the timing of ultrasound application: Comparative Example 3 continued to apply ultrasound in the second stage (75°C). Although the shear force was extremely low (245.7 g), the centrifugal water loss rate was as high as 10.92%. This indicates that the low shear force at this point was not due to benign tenderization, but rather because the continuous mechanical vibration shattered the already formed gel network, leading to the disintegration of the muscle tissue structure and a significant decrease in water-holding capacity. This result confirms the necessity of limiting the second stage of ultrasound to be turned off in this invention, i.e., maintaining a silent thermal field to stabilize the structure during actin denaturation and gel fixation.

[0065] Synergistic effect of temperature gradient: In Comparative Example 4, the 75°C intermediate temperature transition zone was missing, resulting in a surge in shear force to 890.3g and a decrease in yield. This was because actin did not undergo the slow denaturation adaptation in the intermediate temperature zone and directly encountered the high temperature of 95°C, causing violent contraction and dehydration. Example 1, through three-stage temperature control, achieved stepwise and orderly denaturation of different protein components, ensuring ripening while avoiding fiber hardening.

[0066] Effects of thermal blockade on texture: Although the yield of Comparative Example 5 was similar to that of Example 1 (due to the same heating process), the shear force (362.4g) was significantly higher than that of Example 1 (295.3g). This indicates that without the 0-4°C ice-cold step, the residual heat in the center would continue to act, causing excessive protein denaturation, increasing the toughness of the meat, and failing to achieve the optimal tenderness index.

[0067] In summary, the process parameter combination shown in Example 1 (55℃ ultrasonic sol + 75℃ silent curing + 95℃ setting + ice cream) achieved the best balance between yield, tenderness and structural stability, and its physicochemical data were superior to those of the traditional process and the control group with a single variable missing.

[0068] Test Example 2: Sensory Evaluation Test This section evaluates the sensory quality of the squid salad samples prepared in each embodiment and comparative example, aiming to quantify the impact of different process parameters on the final eating experience of the product using statistical methods. Evaluation team formation: The evaluation team consisted of 12 professionals trained in food sensory evaluation systems. All evaluators were familiar with the textural characteristics of processed seafood and had not consumed any irritating foods within two hours prior to the test.

[0069] Evaluation criteria and methods: A double-blind testing method was used, and samples were submitted after being randomly coded. Pure water and unflavored soda crackers were provided between each round of testing to remove any lingering taste. A 10-point scoring system was used, with the specific dimensions defined as follows: Tenderness: The degree of resistance that teeth encounter when cutting muscle fibers during chewing. A higher score indicates less resistance and a softer, more tender texture.

[0070] Juiciness: The amount of juice released from the sample during chewing and the feeling of moisture in the mouth. The higher the score, the stronger the juiciness.

[0071] Crispness: The instantaneous breaking sensation and rebound feedback experienced upon the first bite. A higher score indicates a crisper texture, without any mushy or mushy feeling.

[0072] Overall acceptability: A comprehensive evaluation based on flavor, texture, and appearance.

[0073] Test results: The sensory evaluation statistics of each group of samples are shown in Table 2.

[0074] Table 2 Summary of sensory quality scores for samples in each group Results Analysis and Conclusions: Based on the sensory rating data in Table 2 and the technical mechanism of this invention, the analysis is as follows: Synergistic effect of physical field and gel network: Example 1 achieved the highest scores in all indicators, verifying the effectiveness of the combination of acoustic-thermal coupling, gradient ripening, and heat-blocking processes. Compared with Comparative Example 2 (without ultrasound), Example 1 showed improved tenderness and juiciness scores (approximately 2.6 and 2.7 points respectively). This indicates that the ultrasonic cavitation effect in the first stage effectively improved the solubility of myosin and the water-holding capacity of the gel, allowing the finished product to retain internal moisture while reducing chewing resistance.

[0075] Excessive physical field damage to texture: Comparative Example 3 (full-process ultrasound) exhibited a highly characteristic score distribution: a high tenderness score (8.9) but an extremely low crispness score (3.4), resulting in a significant decrease in overall acceptability (5.2). Evaluators reported that this group of samples had a soft, mushy texture, a loose structure, and lacked chewiness. This result corroborates the high centrifugal water loss rate in Test Example 1, confirming that failing to turn off ultrasound in the second stage causes the formed gel network to break down, reducing firmness but sacrificing the crispness characteristic of squid products.

[0076] The decisive role of heat-blocking process in crispness: Comparative Example 5 (without ice cream) showed acceptable tenderness and juiciness, but its crispness score (4.2) was lower than that of Example 1 (9.4). The data indicates that the rapid cooling step from 0-4°C, by causing instantaneous contraction of the surface layer of muscle fibers through sudden cooling, is crucial for creating the unique texture of crisp on the outside and tender on the inside. If this step is omitted, the slow cooling process will cause excessive softening of collagen, resulting in a product with a soft rather than crisp texture.

[0077] The necessity of temperature gradient: Comparative Example 4 (lacking medium temperature) had a tenderness score of only 5.1, close to that of conventional cooking (Comparative Example 1). This indicates that the lack of transitional ripening at 75℃ caused actin to contract and harden rapidly at high temperatures, resulting in a rough texture. Even the initial ultrasonic treatment could not compensate for the textural loss caused by the later thermal denaturation.

Claims

1. A method for processing squid salad based on gradient temperature curing, characterized by, Includes the following steps: S1. Raw material pretreatment: Cut the thawed squid into pieces, soak them in the seasoning solution, and drain. S2, Acoustic-thermal coupling gradient ripening: (1) Acoustic-thermal synergistic zone: Immerse the squid in a medium at 53-57°C and simultaneously turn on ultrasonic-assisted treatment for 10-15 minutes; the medium is the conditioning liquid described in step S1; (2) Heat field dominance zone: Place the squid in a medium of 73-77℃, turn off the ultrasonic waves, and let it stand to cook for 5-8 minutes; (3) Safety barrier zone: Place the squid in a medium at 90-95℃ and heat for 60-90 seconds; S3, Gradient thermal blockade: After step S2, immediately immerse the squid in a mixture of ice and water at 0-4℃ to cool until the core temperature drops below 10℃, then drain to obtain cooked squid rings; S4. Mixing: Mix the cooked squid rings, mixed vegetables and salad dressing evenly to get the mixed squid salad; The salad dressing is made from the following components by weight percentage: 35%-40% vegetable oil, 20%-25% water, 8%-10% flavoring acid, 10%-12% pasteurized egg yolk liquid, 5%-8% white sugar, 1%-1.5% edible salt, and 0.8%-1.2% compound emulsifying stabilizer, with the remainder being seasoning ingredients and water.

2. The gradient temperature curing based processing method of squid salad according to claim 1, characterized in that, The composite emulsifying stabilizer comprises the following components in parts by weight: 40-50 parts modified corn starch, 15-20 parts xanthan gum, 10-15 parts guar gum, 15-20 parts soy protein isolate, and 5-10 parts dispersing carrier.

3. The squid salad processing method based on gradient temperature cooking according to claim 2, characterized in that, In the composite emulsifying stabilizer, the modified corn starch is acetylated distarch phosphate; the dispersion carrier is maltodextrin.

4. The squid salad processing method based on gradient temperature cooking according to claim 2, characterized in that, The composite emulsifying stabilizer is prepared by the following method: Place the powder components in a mixer and mix them at 18-22 rpm for 15-20 minutes in an environment with a temperature of 20-25℃ and a relative humidity of <40% until the uniformity of mixing (CV value) is less than 5%. Then, pass the mixture through an 80-mesh sieve to obtain the final product.

5. The squid salad processing method based on gradient temperature cooking according to claim 1, characterized in that, In step S1, the thickness or width of the cut squid is controlled between 0.8cm and 1.2cm; the conditioning solution is composed of the following components by mass percentage: sodium chloride 0.8%-1.2%, sodium citrate 0.2%-0.3%, sodium bicarbonate 0.05%-0.1%, and the balance is water; the pH of the conditioning solution is adjusted to 7.2-7.5; the ratio of material to solution during soaking is 1:2 to 1:

3.

6. The squid salad processing method based on gradient temperature cooking according to claim 1, characterized in that, In the acoustic-thermal synergistic zone phase of S2 step, the frequency of the ultrasonic wave is controlled to be 28 kHz-40 kHz, the power density is controlled to be 0.3-0.5 W / cm 2 , and the working mode is continuous wave mode.

7. The squid salad processing method based on gradient temperature cooking according to claim 1, characterized in that, In step S3, "immediately" means within 5 seconds after step S2 ends; the cooling time is 8-12 minutes; after draining, centrifugation is used to remove surface water, with a centrifugation speed of 800-1000 rpm.

8. The squid salad processing method based on gradient temperature cooking according to claim 1, characterized in that, In step S4, the salad dressing is prepared as follows: (1) Aqueous phase dissolution: Mix water, flavoring acid solution, white sugar, edible salt, egg yolk liquid and compound emulsifying stabilizer, and hydrate by stirring at low speed; (2) High shear emulsification: Turn on the high shear emulsifier and set the speed to 10,000-12,000 rpm; (3) Oil phase addition: Under shear conditions, add vegetable oil to the aqueous phase over a period of 5-8 minutes; (4) Homogenize: Continue cutting for 2-3 minutes to form a semi-solid sauce.

9. The squid salad processing method based on gradient temperature cooking according to claim 1, characterized in that, In step S1, if the selected squid raw material is Peruvian squid with thicker flesh, the processing time in the acoustic-thermal synergistic zone stage of step S2 is extended to 15-18 minutes, and the ultrasonic frequency is 28kHz-40kHz.

10. The squid salad processing method based on gradient temperature cooking according to claim 1, characterized in that, In step S4, the weight ratio of the cooked squid rings, mixed vegetables and salad dressing is: 50-60 parts cooked squid rings, 25-30 parts mixed vegetables and 15-20 parts salad dressing. The step S4 is followed by: quantitative modified atmosphere packaging of the mixed squid salad and then immediately storing it in a cold storage at 0-4°C.

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