Fat-reducing braised pork processing method based on ultrasonic penetration and phase change temperature control and application

Abstract

The application discloses a kind of processing method and application of fat-reducing stewed pork based on ultrasonic penetration and phase change temperature control, which includes raw material pretreatment, ultrasonic-assisted low-fat penetration pickling, short-time blanching, oil-free low-temperature stir-frying, phase change temperature control stewing, gradient temperature rising juice collection steps.The application strengthens mass transfer through ultrasonic cavitation effect, simultaneously realizes uniform penetration of flavor substances and pre-solubility of fat;Combined with phase change material precise constant temperature stewing, maintain the state of micro-boiling not violent boiling, reduce fat emulsification and muscle protein denaturation, build a multi-level synergistic fat reduction system.The total fat content of the obtained stewed pork is reduced by 32%~38% compared with traditional process, the shear force is reduced by 15%~22%, the meat is soft and glutinous, the flavor is rich and uniform, and the health attribute is significantly improved.The process parameters of the method are quantifiable and controllable, the product consistency is high, it is suitable for industrialized continuous production, and meets the dietary consumption demand of low-fat and healthy.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, and in particular relates to a method and application of fat-reducing braised pork processing based on ultrasonic permeation and phase change temperature control. Background Technology

[0002] Braised pork belly is a highly representative traditional Chinese meat product. It is made from pork belly through multiple processes such as blanching, stir-frying, braising, and reducing the sauce. With its bright red color, tender and juicy texture, and rich soy sauce flavor, it is loved by consumers and is an important category in the industrialization and standardization of Chinese cuisine.

[0003] Traditional braised pork belly is high in fat, with conventionally prepared braised pork belly typically containing over 30% total fat and high cholesterol, which conflicts significantly with current consumer demands for low-fat and healthy diets. The process lacks standardization; the cooking temperature and time are highly dependent on operator experience, resulting in significant temperature fluctuations and substantial differences in fat content, texture, and flavor intensity between batches, making it difficult to achieve consistent quality in large-scale industrial production. Furthermore, it's difficult to balance fat reduction with quality. Extended cooking times to reduce fat content often lead to excessive denaturation of muscle proteins and tough, aging meat fibers. Simultaneously, high-temperature, vigorous boiling accelerates the loss of flavor compounds and nutrients, failing to simultaneously meet the multiple requirements of fat reduction, tenderness, and flavor retention.

[0004] Existing technologies for improving the fat reduction processing of braised pork mainly employ methods such as long-term stewing and oil draining, low-fat seasoning formulas, enzymatic degreasing, and high-pressure degreasing. Long-term stewing and oil draining promotes fat dissolution by extending the high-temperature simmering time. While simple to operate, the processing cycle is over 2 hours, resulting in low production efficiency. Furthermore, the continuous high temperature can damage the meat's tissue structure, leading to a soft and mushy texture. Enzymatic degreasing uses lipases to break down fat in muscle and adipose tissue, but its degreasing efficiency is limited. Enzyme residues can easily remain and alter the original flavor of the meat, posing risks of flavor degradation and food safety. High-pressure degreasing accelerates fat extraction using a high-pressure environment, increasing the degreasing rate. However, the high pressure severely damages the integrity of muscle fibers, resulting in a tough, chewy texture that fails to retain the traditional soft and tender texture of braised pork. Overall, existing fat reduction technologies all have significant shortcomings, failing to achieve a balance between fat reduction effectiveness, taste quality, and production efficiency. Summary of the Invention

[0005] Therefore, this invention provides a method and application for processing low-fat braised pork based on ultrasonic infiltration and phase change temperature control, which solves the problems of high fat content, reliance on experience in cooking, and poor consistency of traditional braised pork.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control, comprising the following steps:

[0007] (1) Raw material pretreatment: Select pork belly, remove the skin and cut it into pieces. Soak it in water to remove blood and drain it for later use.

[0008] (2) Ultrasonic-assisted low-fat penetrating marinating: Prepare a marinating solution containing low-fat additives and flavor components. Mix the meat pieces with the marinating solution and place them in an ultrasonic reactor. Penetrating marinating is completed through the action of the ultrasonic field, and flavor substances are simultaneously penetrated and fat is pre-dissolved.

[0009] (3) Short blanching: Blanch the marinated meat pieces in boiling water, skim off the blood foam, rinse and drain.

[0010] (4) Low-oil shaping and stir-frying: Use a pot to stir-fry the meat pieces at a low temperature. No additional cooking oil is added during the stir-frying process. The meat pieces rely on their own fat to be released. After stir-frying, pour out the released oil to complete the initial fat reduction and surface shaping.

[0011] (5) Phase change temperature controlled braising and stewing: After stir-frying, put the meat pieces into the phase change temperature controlled cooking equipment, add the seasoning broth, and stew at a phase change temperature of 92±3℃ in a closed constant temperature, keeping it at a gentle boil and not boiling violently.

[0012] (6) Gradient heating to reduce the sauce: After stewing, the phase change temperature is increased to 98±2℃ to reduce the sauce. After the sauce is thick and evenly coats the meat pieces, it is removed from the pot and cooled to obtain the finished product of low-fat braised pork.

[0013] This invention constructs a graded fat reduction system through the coupling effect of ultrasonic-assisted penetration and phase change temperature control. Utilizing the cavitation effect of the ultrasonic field, some fat cell structures are disrupted in advance during the marinating stage, achieving pre-dissolution of fat and rapid, uniform penetration of flavor substances. Initial fat reduction is achieved by releasing free surface fat through low-temperature, oil-free stir-frying. The latent heat and constant temperature characteristics of the phase change material stabilize the stewing temperature range, avoiding excessive emulsification of fat and excessive denaturation of muscle proteins caused by high-temperature, violent boiling. Finally, gradient heating ensures flavor adhesion while controlling the final oil content, forming a continuous fat reduction and quality control path of pre-dissolution, initial separation, and controlled retention, balancing fat reduction effectiveness with product taste, flavor, and quality.

[0014] As a preferred method for processing lean braised pork belly based on ultrasonic infiltration and phase change temperature control, in step (1), the pork belly is cut into 3-4cm cubes and soaked in water for at least 30 minutes. The 3-4cm cube size matches the optimal path for subsequent ultrasonic infiltration and stewing mass transfer. If the size is too small, the meat will easily break apart and lose its elasticity during stewing. If the size is too large, it will prolong the time for flavor penetration and fat dissolution, reducing processing efficiency. Soaking in water for more than 30 minutes allows the blood and soluble proteins inside the meat to dissolve fully through osmotic pressure, reducing the amount of blood foam generated during subsequent stewing, reducing the fishy smell of the finished product, and preventing blood from mixing into the broth and affecting the color and flavor purity of the finished product.

[0015] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (2), the marinade consists of the following components by mass: 100 parts water, 5-8 parts cooking wine, 3-5 parts light soy sauce, 1-2 parts ginger slices, 1-2 parts scallion segments, 0.5-1 parts xylitol, 0.1-0.3 parts compound phosphate, and 0.2-0.5 parts konjac glucomannan. The flavor substances in the cooking wine, scallions, and ginger can penetrate into the muscle tissue to mask the fishy smell of the meat, while the light soy sauce provides a basic salty and savory flavor. Xylitol replaces traditional sucrose to provide a sweet taste, while reducing the calorie load of the finished product, thus meeting the needs of a healthy diet. The compound phosphate can improve the water-holding capacity of muscle protein, avoid excessive water loss during subsequent heating, which would lead to tough meat, and improve the tenderness and yield of the meat. Konjac glucomannan, as a water-soluble dietary fiber, can form a thin hydrophilic protective film on the surface of meat, reducing excessive fat dissolution and nutrient loss during stewing, while enhancing the meat's moisture and tender texture, thus complementing the fat reduction process.

[0016] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (2), the mass ratio of meat chunks to marinade is 1:1.5~1:2; the ultrasonic field processing parameters are: frequency 20~40kHz, power 150~300W, processing temperature 20~30℃, and processing time 20~40min. This material-to-liquid ratio range ensures that the meat chunks are completely immersed in the marinade, providing a uniform liquid environment for ultrasonic mass transfer and avoiding uneven penetration caused by insufficient material. Low-frequency ultrasound of 20~40kHz generates a strong cavitation effect, forming microjets and microchannels inside the muscle tissue, breaking the mass transfer resistance of the cell membrane, and accelerating the diffusion of flavor substances into the meat chunks. The power range of 150~300W can ensure penetration and fat dissolving efficiency while avoiding excessive power that could damage the integrity of muscle fibers and prevent the meat from becoming soft and losing its elasticity. A processing temperature of 20-30℃ maintains the stability of flavor compounds in the marinade while preventing premature denaturation of muscle proteins due to elevated temperatures, thus ensuring the tenderness of the product. A processing time of 20-40 minutes allows for even penetration of flavor compounds and moderate pre-dissolution of fat, avoiding damage to the meat structure caused by excessive processing time.

[0017] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (2), the mass ratio of meat chunks to marinade is 1:1.8; the ultrasonic treatment parameters are: frequency 28kHz, power 200W, treatment temperature 25℃, and treatment time 30min. This set of parameters represents the optimal matching conditions for ultrasonic penetration and fat pre-dissolution. The 1:1.8 material-to-liquid ratio ensures immersion while controlling the amount of marinade, reducing raw material costs and subsequent waste liquid treatment load. The 28kHz ultrasonic frequency has moderate cavitation intensity, which can form a uniform microchannel structure in the muscle tissue, ensuring both the penetration depth and uniformity of flavor substances without causing excessive damage to muscle fibers. The synergistic effect of 200W power and 30min treatment time allows the fat pre-dissolution efficiency to reach its peak, while the flavor components in the marinade penetrate to the center of the meat chunks, avoiding uneven flavor inside and outside. At room temperature of 25℃, no additional heating or cooling is required, which meets the energy consumption control requirements of industrial production, while maintaining the stability of the physicochemical properties of each component in the pickling system.

[0018] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (3), the marinated pork pieces are blanched in boiling water for 3-5 minutes, and then rinsed with warm water. Short blanching in boiling water allows the muscle protein on the surface of the pork to quickly denature and coagulate, locking in the flavor substances and moisture inside the pork, preventing a large loss of nutrients and flavor components during subsequent stewing. The 3-5 minute blanching time effectively removes residual blood and soluble impurities without overcooking the pork, ensuring efficient flavor absorption during subsequent stewing. Rinsing with warm water prevents the pork from shrinking drastically due to temperature differences, preventing the surface from hardening and the loss of internal juices, maintaining the elasticity and tenderness of the pork, and washing away surface blood and impurities to ensure the pure color of the finished product.

[0019] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (4), a non-stick pan or a phase change temperature-controlled pan is used for stir-frying for 3-5 minutes. After stir-frying until the surface of the meat pieces is slightly yellow, all the extracted oil is poured out. During the low-temperature stir-frying process, the fat cells on the surface of the meat pieces rupture due to heat, and free fat is continuously extracted. No additional cooking oil is needed to achieve surface frying and shaping, thus reducing the intake of external oil from the source. The stir-frying time of 3-5 minutes can form a uniform caramelized layer on the surface of the meat pieces, giving the finished product a caramelized flavor and a bright red appearance, while avoiding excessive fat extraction and dry meat due to excessive stir-frying time. Pouring out all the extracted oil can directly reduce the total fat content of the finished product, completing the initial fat reduction step. The non-stick pan or phase change temperature-controlled pan can achieve low-temperature uniform heating, avoiding local overheating that causes the meat pieces to burn, and ensuring the controllability and consistency of the stir-frying process.

[0020] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (5), the seasoning broth includes water, dark soy sauce, rock sugar, star anise, cinnamon, and bay leaves; the amount of seasoning broth added covers 2 / 3 of the pork pieces; the constant temperature stewing time is 50-80 minutes. Among them, dark soy sauce provides color and basic soy sauce aroma, rock sugar harmonizes the flavor and enhances the gloss, and spices such as star anise, cinnamon, and bay leaves give the finished product a complex spice flavor, forming the typical flavor characteristics of traditional braised pork. Adding the seasoning broth to cover 2 / 3 of the pork pieces can form steam convection heating in a closed stewing environment, which not only ensures that the pork pieces are in full contact with the seasoning liquid, but also avoids excessive dilution of the flavor by the broth, and at the same time reduces the amount of water evaporation during the stewing process. The constant temperature stewing time of 50-80 minutes allows the fat inside the pork pieces to gradually dissolve, while the muscle fibers slowly degrade under gentle heating conditions, forming a soft and tender texture, ensuring that the flavor substances fully penetrate into the inside of the pork pieces.

[0021] As a preferred method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control, in step (5), the phase change temperature is 92℃ and the constant temperature stewing time is 60min. The constant temperature range of 92℃ is in a state of slight boiling, which can ensure the heat transfer efficiency of the stewing process, allowing the fat to gradually dissolve and the muscle fibers to degrade appropriately, while avoiding the aggravation of fat emulsification, turbidity of the soup, and excessive denaturation of proteins caused by violent boiling. At this temperature, the phase change material maintains a constant temperature through the release and absorption of latent heat of solid-liquid phase change, controlling the temperature fluctuation within a very small range, eliminating the impact of temperature fluctuations in traditional stewing on product quality, and improving batch-to-batch consistency. The stewing time of 60min is the optimal balance point between fat dissolution and meat tenderization, which can make the finished product have a soft and tender texture, while controlling the amount of fat dissolution within a reasonable range to avoid excessive fat loss leading to bland flavor.

[0022] As a preferred method for processing lean braised pork based on ultrasonic penetration and phase change temperature control, in step (6), the simmering time is 10-20 minutes; after cooling, the finished product can be eaten directly or vacuum-packed; in step (6), the phase change temperature is 98℃ and the simmering time is 15 minutes. Raising the temperature to 98℃ can accelerate the evaporation rate of water in the broth, so that the seasoning broth gradually concentrates and evenly coats the surface of the meat, improving the gloss and flavor concentration of the finished product. A simmering time of 10-20 minutes can make the broth reach a suitable consistency, avoiding insufficient simmering that results in a weak flavor, or excessive simmering that results in a bitter taste and a rebound in oil content. 98℃ and 15 minutes are the optimal simmering parameters, which ensure the broth adheres to the wall and prevent secondary oil production and meat aging due to excessive temperature and time. Vacuum packaging isolates oxygen and microorganisms, extends the shelf life of the finished product, and meets the needs of industrial distribution. The ready-to-eat form is suitable for catering terminals and fresh consumption scenarios, covering different application channels.

[0023] This invention also provides a low-fat braised pork product, prepared using the aforementioned low-fat braised pork processing method based on ultrasonic infiltration and phase change temperature control. This product, prepared through the above-mentioned graded fat reduction and quality control process, significantly reduces total fat content while retaining the tender texture and rich soy sauce flavor of traditional braised pork. Cholesterol content and calorie load decrease simultaneously, aligning with contemporary healthy eating trends. Furthermore, the process parameters are fully controllable, ensuring high batch-to-batch quality consistency. It can be served as a ready-to-eat dish to meet daily consumption needs, or as a pre-prepared food product suitable for diverse scenarios of industrialized catering and convenient home consumption.

[0024] The present invention has the following advantages:

[0025] This invention utilizes ultrasonic cavitation to disrupt the structure of some fat cells, achieving pre-dissolution of fat during the marinating stage; it employs oil-free, low-temperature stir-frying to extract and directly remove surface free fat; and it combines this with phase-change constant-temperature micro-boiling stewing to avoid excessive emulsification and reflux of fat caused by vigorous boiling. Compared to traditional processes, the total fat content of the finished product is reduced by 32%~38%, and the cholesterol content is reduced by 18%~25%, significantly reducing the burden of oil intake and aligning with the trend of healthy eating.

[0026] The phase change temperature control technology of this invention stabilizes the stewing temperature in the micro-boiling range of 92±3℃, avoiding excessive denaturation of muscle proteins and aging of meat fibers caused by high-temperature and violent boiling. The shear force of the finished product is reduced by 15%~22%, and the meat is tender, juicy, and not dry or mushy. Ultrasonic-assisted marinating enhances the mass transfer efficiency of flavor substances, allowing the seasoning components to penetrate evenly into the meat, solving the problem of uneven flavor inside and outside the meat in traditional processes. Gradual heating and reducing the sauce ensures that the sauce is thick and coats the meat, fully preserving the bright red color and rich soy sauce flavor of the braised pork.

[0027] The cavitation effect and microjet action of ultrasound in this invention can form mass transfer microchannels in muscle tissue, which greatly improves the penetration rate of the marinade and reduces the marinating time to 20-40 minutes, which is significantly better than the several hours of traditional static marinating. The stable constant temperature heating mode of phase change temperature control improves heat exchange efficiency, and the stewing time is significantly shortened compared with traditional processes, thereby improving overall processing efficiency and reducing production energy consumption and time costs. Attached Figure Description

[0028] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0029] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0030] Figure 1 This is a schematic diagram of the process for processing lean braised pork based on ultrasonic infiltration and phase change temperature control provided in an embodiment of the present invention;

[0031] Figure 2This is a bar chart showing the comparison of fat content, shear force, sensory score, and fat loss rate for Examples 1, 2, 3, and the comparative examples.

[0032] Figure 3 The above are radar charts showing the overall quality of Examples 1, 2, 3 and the comparative examples. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0034] Example 1

[0035] See Figure 1 Example 1 is the optimal implementation method, and the specific preparation steps are as follows:

[0036] Raw material pretreatment: Select fresh pork belly with skin, remove the skin and cut it into uniform cubes of 3.5cm. Weigh 635g of meat cubes and soak them in clean water at room temperature for 30 minutes to fully remove blood and soluble impurities. Then, take them out and drain the surface water for later use.

[0037] Ultrasonic-assisted low-fat penetrating marinating: Prepare the marinating solution by weight as follows: 1000g water, 60g cooking wine, 40g light soy sauce, 15g ginger slices, 15g scallion segments, 8g xylitol, 2g food-grade compound phosphate, and 3g konjac glucomannan. Stir until the soluble components are completely dissolved. Place the drained meat pieces and marinating solution into the ultrasonic reactor at a weight ratio of 1:1.8. Set the ultrasonic frequency to 28kHz, ultrasonic power to 200W, and system temperature to 25℃. Perform ultrasonic treatment for 30 minutes to simultaneously complete the penetration of flavor substances and pre-dissolution of fat.

[0038] Briefly blanch to remove blood foam: Put the ultrasonically marinated meat pieces into boiling water and blanch for 4 minutes, continuously skimming off the blood foam floating on the surface. After blanching, remove the meat pieces, rinse them with warm water to remove any remaining impurities, and drain them again for later use.

[0039] Oil-free low-temperature stir-frying for shaping: Place the drained meat pieces into a preheated non-stick pan at a suitable temperature. Do not add any additional cooking oil throughout the process. Stir-fry at a low temperature for 4 minutes until the surface of the meat pieces turns a uniform light yellow. Stir occasionally to ensure even heating. After stir-frying, pour off all the free oil that has been extracted to complete the initial fat reduction and surface shaping.

[0040] Phase change temperature controlled braising and stewing: Transfer the stir-fried meat pieces into the phase change temperature controlled cooking equipment, add the seasoning broth made by mixing water, dark soy sauce, rock sugar, star anise, cinnamon, and bay leaves in the usual braising seasoning ratio, and the broth should cover 2 / 3 of the meat pieces' volume; set the phase change temperature control point of the equipment to 92℃, and stew at a constant temperature for 60 minutes under sealed conditions, maintaining a gentle simmer throughout the process.

[0041] Gradient heating and reducing sauce: After stewing, raise the phase change temperature control point to 98℃ and continue to reduce the sauce at a constant temperature for 15 minutes until the sauce is thick and evenly coats the surface of the meat pieces; after turning off the heat, remove the meat pieces and let them cool naturally to room temperature to obtain the finished low-fat braised pork, which can be eaten directly or stored in the refrigerator after vacuum packaging.

[0042] Example 2

[0043] This embodiment adjusts some process parameters, and the specific preparation steps are as follows:

[0044] Raw material pretreatment: Select fresh pork belly with skin from the same batch as in Example 1, remove the skin and cut it into uniform cubes of 3cm. Weigh 762g of the meat cubes and soak them in clean water at room temperature for 30 minutes to fully remove blood and soluble impurities. Then, take them out and drain the surface water for later use.

[0045] Ultrasonic-assisted low-fat penetrating marinating: Prepare the marinating solution by weight as follows: 1000g water, 50g cooking wine, 30g light soy sauce, 10g ginger slices, 10g scallion segments, 5g xylitol, 1g food-grade compound phosphate, and 2g konjac glucomannan. Stir until the soluble components are completely dissolved. Place the drained meat pieces and marinating solution into the ultrasonic reactor at a weight ratio of 1:1.5. Set the ultrasonic frequency to 35kHz, ultrasonic power to 250W, and system temperature to 28℃. Perform ultrasonic treatment for 25 minutes to simultaneously complete the penetration of flavor substances and pre-dissolution of fat.

[0046] Briefly blanch to remove blood foam: Put the ultrasonically marinated meat pieces into boiling water and blanch for 3 minutes. During the process, continuously skim off the blood foam and impurities that float to the surface. After blanching, take out the meat pieces and rinse them with 30-40℃ warm water to remove any remaining foam and impurities. Drain the surface water again and set aside.

[0047] Oil-free low-temperature stir-frying for shaping: Place the drained meat pieces into a preheated non-stick pan. Do not add any additional cooking oil. Stir-fry at a low temperature for 3 minutes, turning occasionally to ensure that all sides of the meat pieces are heated evenly. Stir-fry until the surface of the meat pieces turns a uniform light yellow color. Then, pour out all the free oil that has separated in the pan to remove it. This completes the initial fat reduction and surface shaping.

[0048] Phase change temperature controlled braising and stewing: Transfer the stir-fried meat pieces into the phase change temperature controlled cooking equipment, add the seasoning broth made by mixing water, dark soy sauce, rock sugar, star anise, cinnamon, and bay leaves in the usual braising seasoning ratio, and the broth should cover 2 / 3 of the meat pieces' volume; set the phase change temperature control point of the equipment to 90℃, and stew at a constant temperature for 70 minutes under sealed conditions, maintaining a gentle simmer throughout the process to avoid excessive emulsification and reflux of fat.

[0049] Gradient heating and reducing sauce: After stewing, raise the phase change temperature control point to 97℃ and continue to reduce the sauce at a constant temperature for 12 minutes until the sauce is thick and evenly coats the surface of the meat pieces; after turning off the heat, remove the meat pieces and let them cool naturally to room temperature to obtain the finished low-fat braised pork, which can be eaten directly or stored in the refrigerator after vacuum packaging.

[0050] Example 3

[0051] This embodiment adjusts some process parameters, and the specific preparation steps are as follows:

[0052] Raw material pretreatment: Select fresh pork belly with skin from the same batch as in Example 1, remove the skin and cut it into uniform cubes of 4cm. Weigh 571.5g of the meat cubes and soak them in clean water at room temperature for 30 minutes to fully remove blood and soluble impurities. Then, take them out and drain the surface water for later use.

[0053] Ultrasonic-assisted low-fat penetrating marinating: Prepare the marinating solution, by weight, as follows: 1000g water, 80g cooking wine, 50g light soy sauce, 20g ginger slices, 20g scallion segments, 10g xylitol, 3g food-grade compound phosphate, and 5g konjac glucomannan. Stir until the soluble components are completely dissolved. Place the drained meat pieces and marinating solution into the ultrasonic reactor at a weight ratio of 1:2. Set the ultrasonic frequency to 25kHz, ultrasonic power to 180W, and system constant temperature to 22℃. Perform ultrasonic treatment for 35 minutes to simultaneously complete the penetration of flavor substances and pre-dissolution of fat.

[0054] Briefly blanch to remove blood foam: Put the ultrasonically marinated meat pieces into boiling water and blanch for 5 minutes. During the process, continuously skim off the blood foam and impurities that float to the surface. After blanching, take out the meat pieces and rinse them with 30-40℃ warm water to remove any remaining foam and impurities. Drain the surface water again and set aside.

[0055] Oil-free low-temperature stir-frying for shaping: Place the drained meat pieces into a preheated non-stick pan. Do not add any additional cooking oil. Stir-fry at a low temperature for 5 minutes, turning occasionally to ensure that all sides of the meat pieces are heated evenly. Stir-fry until the surface of the meat pieces turns a uniform light yellow color. Then, pour out all the free oil that has separated in the pan to remove it. This completes the initial fat reduction and surface shaping.

[0056] Phase change temperature controlled braising and stewing: Transfer the stir-fried meat pieces into the phase change temperature controlled cooking equipment, add the seasoning broth made from water, dark soy sauce, rock sugar, star anise, cinnamon, and bay leaves in the usual braising seasoning ratio, and the broth should cover 2 / 3 of the meat pieces' volume; set the equipment's phase change temperature control point to 94℃, and stew at a constant temperature for 55 minutes under sealed conditions, maintaining a gentle simmer throughout the process to prevent excessive emulsification and reflux of fat.

[0057] Gradient heating and reducing sauce: After stewing, raise the phase change temperature control point to 99℃ and continue to reduce the sauce at a constant temperature for 18 minutes until the sauce is thick and evenly coats the surface of the meat pieces; after turning off the heat, remove the meat pieces and let them cool naturally to room temperature to obtain the finished low-fat braised pork, which can be eaten directly or stored in the refrigerator after vacuum packaging.

[0058] Comparative Example 1

[0059] Using the traditional home-style braised pork recipe as a control, the specific preparation steps are as follows:

[0060] Select fresh pork belly with skin from the same batch as in Example 1, remove the skin and cut it into uniform cubes of 3.5cm. Weigh out the same amount of pork cubes as in Example 1, put them into boiling water and blanch for 5 minutes, continuously skimming off any blood foam that rises to the surface. After blanching, remove the pork cubes, rinse them with warm water to remove any surface impurities, and drain them for later use. Add vegetable oil and rock sugar to a wok, heat over low heat while stirring constantly until the rock sugar is completely melted and turns a reddish-brown color. Quickly add the blanched pork pieces to the wok and stir-fry continuously to coat each piece of meat evenly with the caramelized sugar. Then add light soy sauce, dark soy sauce, and cooking wine for seasoning. Add ginger slices, scallion segments, star anise, cinnamon, bay leaves, and other spices and stir-fry until fragrant. Add enough water to completely cover the pork pieces. Heat over high heat until the broth boils, then reduce to the lowest heat, cover, and simmer for 120 minutes, checking the remaining broth occasionally to prevent it from drying out and burning. After simmering, turn up the heat to high and reduce the sauce for 10 minutes, stirring constantly to prevent the bottom from becoming mushy. Continue until the sauce is thick and evenly coats the pork pieces. Turn off the heat and remove from the wok. Let it cool naturally to room temperature to obtain a traditional braised pork control sample.

[0061] Effect verification

[0062] The finished products of Examples 1-3 and Comparative Example 1 were subjected to quality index testing. The fat content was determined using the Soxhlet extraction method according to GB5009.6-2016 "National Food Safety Standard - Determination of Fat in Food". Shear force was tested using a texture analyzer for tenderness. Sensory evaluation was conducted by 10 qualified food tasters, considering five dimensions: color, aroma, flavor, taste, and texture, with a maximum score of 100 points. The fat reduction rate was calculated based on Comparative Example 1. The test results are shown in Table 1.

[0063]

[0064] Table 1. Comprehensive evaluation and comparison results of Examples 1, 2, 3 and the comparative examples.

[0065] See Figure 2 The fat content of Comparative Example 1 (traditional process) was 33.7%, while the fat content of the three examples was 21.3%, 22.7%, and 22.1%, respectively, all significantly lower than the comparative example, with a reduction of 32% to 37%. This indicates that the method described in this invention can effectively promote the precipitation and removal of fat during the processing of braised pork, achieving a significant fat reduction effect. Shear force is a key mechanical indicator for measuring the tenderness of meat products; the lower the value, the softer the meat. The shear force of Comparative Example 1 was 49.2 N, while the three examples reduced it to the range of 38.5 to 41.2 N, a reduction of approximately 16% to 22%. This shows that the fat reduction treatment did not lead to dry meat; on the contrary, due to the water retention control and low-temperature slow cooking process, the muscle fibers were moderately softened, resulting in a more tender and smooth texture.

[0066] Ten professional tasters scored the samples based on five dimensions: color, aroma, flavor, mouthfeel, and texture (out of 100 points). Comparative Example 1 scored 83 points, while the three examples all scored between 89 and 92 points, representing an improvement of 7% to 11%. Example 1, with a score of 92, ranked first, indicating that under the optimal parameter combination, the product achieved superior levels in flavor intensity, color uniformity, and overall palatability. The fat reduction rates of the three examples were 36.8%, 32.6%, and 34.4%, respectively, with an average of approximately 34.6% (shown by the orange dotted line in the figure). The data showed minimal fluctuation across the three sets, indicating good stability and repeatability of the process parameters within the set range.

[0067] See Figure 3 A radar chart (spider plot) was used to overlay the four indicators after normalizing them to the 0-1 range, allowing for a comprehensive comparison of the overall quality performance of each sample. Specifically, fat content and shear force were negative indicators (reverse-processed during normalization), while sensory scores and fat loss rate were positive indicators (higher was better). Figure 3 It can be seen from this that

[0068] Example 1 (blue solid line) covers the largest area and reaches its peak in both fat reduction rate (36.8%) and sensory score (92 points), demonstrating the best overall performance. Example 2 (light blue solid line) is slightly inferior to Example 1 in sensory score (89 points vs. 92 points), but its fat content and shear strength remain at a low level. Example 3 (light blue solid line) has moderate indicators and balanced overall quality. Comparative Example 1 (orange-red dashed line) covers the smallest area and is inferior in fat content, shear strength, and sensory score, with no data available only for fat reduction rate (represented by baseline value). In summary, the process described in this invention achieves significant fat reduction while also improving tenderness and sensory quality. All three examples exhibit good overall quality within the parameter range, verifying the feasibility and robustness of the process.

[0069] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control, characterized in that, Includes the following steps: (1) Raw material pretreatment: Select pork belly, remove the skin and cut it into pieces. Soak it in water to remove blood and drain it for later use. (2) Ultrasonic-assisted low-fat penetrating marinating: Prepare a marinating solution containing low-fat additives and flavor components. Mix the meat pieces with the marinating solution and place them in an ultrasonic reactor. Penetrating marinating is completed through the action of the ultrasonic field, and flavor substances are simultaneously penetrated and fat is pre-dissolved. (3) Short blanching: Blanch the marinated meat pieces in boiling water, skim off the blood foam, rinse and drain. (4) Low-oil shaping and stir-frying: Use a pot to stir-fry the meat pieces at a low temperature. No additional cooking oil is added during the stir-frying process. The meat pieces rely on their own fat to be released. After stir-frying, pour out the released oil to complete the initial fat reduction and surface shaping. (5) Phase change temperature controlled braising and stewing: After stir-frying, put the meat pieces into the phase change temperature controlled cooking equipment, add the seasoning broth, and stew at a phase change temperature of 92±3℃ in a closed constant temperature, keeping it at a gentle boil and not boiling violently. (6) Gradient heating to reduce the sauce: After stewing, the phase change temperature is increased to 98±2℃ to reduce the sauce. After the sauce is thick and evenly coats the meat pieces, it is removed from the pot and cooled to obtain the finished product of low-fat braised pork.

2. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (1), cut the pork belly into 3-4cm cubes and soak them in water for at least 30 minutes.

3. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (2), the marinating liquid is composed of the following components by mass: 100 parts water, 5-8 parts cooking wine, 3-5 parts light soy sauce, 1-2 parts ginger slices, 1-2 parts scallion segments, 0.5-1 parts xylitol, 0.1-0.3 parts compound phosphate, and 0.2-0.5 parts konjac glucomannan.

4. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (2), the mass ratio of meat chunks to marinade is 1:1.5~1:2; the ultrasonic field treatment parameters are: frequency 20~40kHz, power 150~300W, treatment temperature 20~30℃, and treatment time 20~40min.

5. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 4, characterized in that, In step (2), the mass ratio of meat chunks to marinade is 1:1.8; the ultrasonic treatment parameters are: frequency 28kHz, power 200W, treatment temperature 25℃, and treatment time 30min.

6. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (3), the marinated meat pieces are blanched in boiling water for 3-5 minutes, and then rinsed with warm water.

7. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (4), a non-stick pan or a phase change temperature control pan is used for stir-frying. The stir-frying time is 3-5 minutes. After stir-frying until the surface of the meat pieces is slightly yellow, pour out all the extracted oil.

8. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (5), the seasoning broth includes water, dark soy sauce, rock sugar, star anise, cinnamon, and bay leaves; the amount of seasoning broth added covers 2 / 3 of the meat pieces; the constant temperature simmering time is 50~80 minutes; In step (5), the phase change temperature is 92℃ and the constant temperature stewing time is 60min.

9. The method for processing lean braised pork based on ultrasonic infiltration and phase change temperature control according to claim 1, characterized in that, In step (6), the simmering time is 10-20 minutes; after cooling, the finished product can be eaten directly or vacuum packaged; in step (6), the phase change temperature is 98°C and the simmering time is 15 minutes.

10. A low-fat braised pork product, characterized in that, The braised pork was prepared using the method for reducing fat based on ultrasonic infiltration and phase change temperature control as described in any one of claims 1 to 9.

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