Meat ball based on cold fresh pork low-temperature blending technology and preparation method thereof

Abstract

The invention discloses meat balls based on a cold fresh pork low-temperature blending technology and a preparation method of the meat balls, and belongs to the technical field of food processing. The meat ball is prepared from cold fresh pork hind leg meat, medium oil, edible salt, composite phosphate and other raw materials according to a specific ratio. The preparation method comprises the steps of raw material pretreatment, pre-cooling by blending equipment, three-time segmented blending, low-temperature forming and water bath curing, rapid cooling, low-temperature quick freezing and the like. By accurately controlling the blending temperature (less than or equal to 12 DEG C in the whole process), optimizing blending parameters and the raw material ratio and combining segmented water bath curing and fluidized bed quick-freezing technologies, excessive denaturation of protein is effectively avoided, myofibrillar protein is promoted to be fully dissolved out to form stable gel, and the elasticity and juiciness of the meat balls are remarkably improved; meanwhile, nutrient loss and microorganism breeding are inhibited, the shelf life is prolonged to 12 months, the problems of poor taste, nutrient loss, insufficient safety, poor raw material adaptability and the like of a traditional process are solved, and the prepared meat balls are stable in quality, rich in nutrition, safe, reliable and wide in application prospect.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a method for preparing meatballs using chilled fresh pork as raw material through low-temperature pounding technology, with the aim of improving the texture and flavor of the meatballs. Background Technology

[0002] Meatballs, a classic frozen meat product, are widely favored by consumers for their chewy texture and delicious flavor, occupying an important share of the food market. Currently, most meatballs on the market are prepared using a conventional pounding process, which typically uses frozen pork as raw material and mixes and pounds the raw material with auxiliary ingredients at room temperature or under uncontrolled temperature conditions. However, traditional methods have several significant drawbacks: First, the mechanical friction during pounding generates a large amount of heat, causing excessive denaturation of pork protein and damaging the muscle fiber structure, resulting in meatballs that are hard, lack elasticity, and are not juicy. Second, the high-temperature environment accelerates the decomposition of water-soluble vitamins (such as B vitamins) and fat oxidation, which not only reduces the nutritional value of the meatballs but also easily produces unpleasant flavor substances. Third, when pounding at room temperature, the raw materials are in the dangerous microbial growth range of 5-32℃ for a long time, leading to the proliferation of bacteria, increasing the risk of product spoilage, shortening shelf life, and threatening food safety. Fourth, the process has strict requirements on the temperature of the raw materials and is only suitable for frozen pork (-16 to -18℃, thawed to -6℃ before production). If chilled fresh pork at 0-4℃ (24-48 hours after slaughter) is used, conventional pounding cannot fully destroy the meat structure and cannot effectively extract myofibril protein, resulting in meatballs with poor shape retention and easy breakage. In addition, although some existing improved processes attempt to control temperature, the temperature control precision is insufficient, and problems such as protein denaturation and nutrient loss still exist, making it difficult to balance the quality, safety and process stability of meatballs. Summary of the Invention

[0003] To address the problems existing in the aforementioned background technology, the present invention aims to provide a meatball based on low-temperature pounding technology of chilled fresh pork and its preparation method, thereby improving the taste and safety of the meatball. The main technology involves precisely controlling the temperature during the pounding process using low-temperature pounding technology, which can effectively prevent excessive denaturation of the meat, reduce nutrient loss, and inhibit microbial growth, providing a new direction for the high-quality production of chilled fresh pork meatballs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A type of meatball based on low-temperature pounding technology of chilled fresh pork comprises the following ingredients by weight percentage: 70-72% chilled fresh pork hind leg meat (fat content ≤5%), 18-20% medium fat (8mm), 1.0-1.5% edible salt, 1-1.5% white sugar, 0.2-0.3% garlic crisp, 0.3-0.5% compound phosphate (sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate mixed in a weight ratio of 1:2:1), 0.3-0.4% phosphate distarch, 0.2-0.3% fried shallots, 0.4-0.5% white pepper powder, 1.5-2.0% compound seasoning, and 2-2.3% sterile ice water at 0-2℃.

[0005] Preferred method: A method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork is as follows: Step 1: Raw material pretreatment. Select fresh pork hind leg meat that has been slaughtered for 24-48 hours and is kept at a temperature of 0-4℃. After the fascia is cut off by a slicer, cut the meat into 5-8cm square pieces and put them into a meat grinder to grind into minced meat with a particle size of 6-8mm. Set aside. Step 2: Pre-cooling the crushing equipment. Pre-cool the crushing barrel of the dual-speed low-temperature crusher to -15℃. The equipment adopts a closed-loop refrigerant oil temperature control system. The oil temperature is monitored in real time by a PLC controller, and the refrigerant flow is precisely controlled by adjusting the electronic expansion valve. The temperature control accuracy reaches ±1℃. Step 3: First grinding (salt dissolution stage), add the prepared minced meat to the pre-cooled grinding bucket, along with edible salt and compound phosphate, maintain the grinding temperature at 0-2℃, and grind at a low speed of 70-100r / min for 10-15 minutes. Step 4: Secondary grinding (addition of auxiliary materials stage), increase the grinding blade speed to a high speed of 120-150 r / min, maintain the temperature at 0-2℃, and slowly add phosphate distarch, white sugar, fried garlic, fried shallots, white pepper powder, compound seasoning and sterile ice water to the grinding bucket. Grind at high speed for 15-20 minutes, and check the temperature every 5 minutes during this period to ensure that the temperature is ≤12℃. Step 5: Three rounds of pounding (gel formation stage). Reduce the speed to a low speed of 70-100 r / min, keep the temperature ≤12℃, and continue pounding for 5 minutes until the minced meat forms a uniform, delicate, and glossy gel-like consistency. It should also be elastic to the touch and not sticky. This is the end point of the pounding process. Step 6: Low-temperature molding and water bath curing. Place the gel-like minced meat into a molding machine to form spherical blanks with a diameter of 3-3.5cm. Then place them into a flowing water bath and heat to 55℃ at a rate of 1℃ / min and hold for 3 minutes. Then heat to 75-80℃ at the same rate and hold for 2 minutes (ensure the center temperature is ≥70℃). Finally, heat to 90-95℃ at a rate of 1℃ / min and cure for 4 minutes. Step 7: Post-processing. The cooked meatballs are taken out and quickly cooled to a surface temperature of <15℃ by a conveyor belt air cooling system and the surface water droplets are blown away. Then they are placed in a quick-freezing tunnel at -35 to -40℃ and quick-frozen for 30 to 40 minutes with an air speed of 3-5m / s to lower the core temperature to below -18℃. After that, they are packaged and refrigerated for storage.

[0006] Preferred: In step 3, the efficient heat exchange between the refrigerant oil and the minced meat during the pounding process absorbs the heat generated by mechanical friction in real time, ensuring that the temperature of the minced meat is stable at 0-2℃ during the salting stage, promoting the full dissolution of myofibril protein, forming a uniform protein solution, and laying the foundation for gel formation.

[0007] Preferably, in step 5, the gel formation stage promotes the interaction of hydrophobic groups of proteins through low-speed pounding, forming a stable and dense gel network. At the same time, an infrared temperature monitor is used to monitor the temperature of the minced meat in real time, accurately control the pounding endpoint, avoid excessive pounding that could damage the gel structure, and ensure the elasticity and shaping stability of the meatballs.

[0008] Preferred option: In step 6, the flow bath adopts a segmented temperature control system. Through a high-precision temperature sensor and an automatic temperature control device, the heating rate is strictly controlled at 1℃ / min to ensure that the protein gradually coagulates, activates the activity of transglutaminase, improves the strength and taste stability of the meatball gel, and avoids quality defects caused by temperature fluctuations.

[0009] Preferred method: In step 7, the quick-freezing tunnel adopts a fluidized bed conveying method, which uses upward airflow from the bottom to suspend and tumble the meatballs, ensuring that each meatball is evenly exposed to the low-temperature air, freezes quickly and does not stick together. At the same time, it is equipped with a variable frequency wind speed control system to dynamically adjust the wind speed according to the freezing state of the meatballs, so as to avoid the ice crystals being too large and damaging the meat structure, and to retain the nutrition and taste to the maximum extent.

[0010] Compared with the prior art, the present invention has the following beneficial effects: This technical solution, through a series of innovative designs and precise controls, brings significant and outstanding technical effects: First, it achieves a qualitative improvement in taste. Through low-temperature pounding technology (pounding barrel pre-cooled to -15℃, meat paste temperature ≤12℃ throughout the process), it effectively avoids excessive denaturation of pork protein, allowing myofibril protein to fully dissolve and form a stable and dense gel network. This results in meatballs with excellent elasticity, juicy and plump when chewed, neither dry nor hard, with a texture close to high-quality handmade meatballs, solving the core problems of traditional processes that result in a hard texture and insufficient elasticity. Second, it preserves nutrients more fully. The low-temperature environment significantly inhibits the activity of lipoxygenase, reducing the decomposition and loss of water-soluble nutrients such as B vitamins, while also preventing the production of unpleasant flavor substances from fat oxidation, thus improving the nutritional value and flavor purity of the meatballs. Third, it greatly enhances food safety. The entire preparation process (pretreatment, pounding, and shaping) is controlled within a low-temperature range of 0-12℃, completely avoiding the dangerous microbial growth zone of 5-32℃, significantly inhibiting bacterial reproduction. Combined with subsequent rapid cooling and deep freezing processes, the meatballs achieve even better results. Under 18℃ freezing conditions, the product shelf life can be extended to 12 months, significantly reducing the risk of microbial contamination. Fourth, the process stability is significantly improved, making it suitable for chilled fresh pork raw materials. Through precise temperature control, segmented crushing, and optimized proportioning, the problems of poor shape retention and easy breakage of chilled fresh pork meatballs are effectively solved, reducing raw material loss and improving production efficiency. Fifth, through segmented water bath cooking and fluidized bed quick-freezing technology, the uniformity of meatball quality is further ensured, avoiding problems such as excessively large ice crystals and damage to the gel structure. This achieves synergistic optimization of the meatball's taste, nutrition, safety, and shelf life, giving it significant market competitiveness and application value. Detailed Implementation

[0011] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0012] I. Raw material composition and proportions: A type of meatball based on low-temperature pounding technology of chilled fresh pork comprises the following ingredients by weight percentage: 70-72% chilled fresh pork hind leg meat (fat content ≤5%), 18-20% medium fat (8mm), 1.0-1.5% edible salt, 1-1.5% white sugar, 0.2-0.3% garlic crisp, 0.3-0.5% compound phosphate (sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate mixed in a weight ratio of 1:2:1), 0.3-0.4% phosphate distarch, 0.2-0.3% fried shallots, 0.4-0.5% white pepper powder, 1.5-2.0% compound seasoning, and 2-2.3% sterile ice water at 0-2℃.

[0013] Analysis of the above technical content: This formula uses chilled fresh pork hind leg meat (fat content ≤5%) as the core ingredient, accounting for 70-72%, ensuring the purity of the meatball's main meat content while avoiding a greasy taste through low fat content; it is combined with 18-20% 8mm medium oil, which can form uniform oil droplets during heating, enhancing the juiciness; a precise ratio of 1.0-1.5% edible salt and 0.3-0.5% compound phosphate (sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate mixed in a 1:2:1 ratio) is used. The former provides an ionic environment for the dissolution of myofibrillar proteins, while the latter enhances protein stability by chelating metal ions and adjusting pH value. The two work synergistically to lay the foundation for gel formation; at the same time, 0.3-0.4% phosphate distarch is added to improve shapeability and elasticity, 1-1.5% white sugar is added to neutralize the flavor, and spices such as garlic crisps, fried shallots, and white pepper powder are added to give it a classic flavor, 2-2.3%... The 0-2℃ sterile ice water not only regulates the moisture of the minced meat but also helps control the grinding temperature. This formula breaks through the traditional process's reliance on frozen pork and, for the first time, optimizes the proportion of auxiliary materials specifically for the characteristics of chilled fresh pork. It achieves synergy between raw material compatibility, taste and flavor, and process stability, solving problems such as poor shaping, mixed flavor, and nutrient loss caused by the imbalance of raw material ratios in traditional meatballs.

[0014] II. Preparation Method A method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork: Step 1: Raw material pretreatment. Select fresh pork hind leg meat that has been slaughtered for 24-48 hours and is kept at a temperature of 0-4℃. After cutting the fascia with a slicer, cut the meat into 5-8cm square pieces and grind it into minced meat with a particle size of 6-8mm in a meat grinder for later use.

[0015] Analysis of the above technical content: The raw material pretreatment of this solution strictly limits the selection criteria of chilled fresh pork hind leg meat - 24-48 hours after slaughter, at a temperature of 0-4℃. At this stage, the pork is in the late stage of rigor mortis, the pH value is stable at 5.5-6.5, the activity of myofibril protein is high, and there is no putrefaction or spoilage, thus preserving the freshness and nutritional components of the meat to the maximum extent. The fascia is cut by a slicer to avoid fascia residue affecting the delicate taste of the meatballs. The meat is cut into 5-8cm square pieces to facilitate uniform grinding in the subsequent process. The meat is ground into 6-8mm particle size, which not only ensures the looseness of the meat paste, which is conducive to ion penetration in the subsequent salting-in stage, but also avoids premature protein denaturation due to excessively small particle size. This step clarifies for the first time the key parameters of chilled pork pretreatment (time, temperature, meat block size, and minced meat particle size), solving the problems of traditional processes that are rough in processing chilled pork and uneven in minced meat state, which leads to insufficient protein dissolution and easy breakage of meatballs. It achieves precise connection between raw material pretreatment and low-temperature crushing technology, laying a stable material foundation for subsequent processes.

[0016] Step 2: Pre-cooling the crushing equipment. The crushing barrel of the dual-speed low-temperature crusher is pre-cooled to -15℃. The equipment adopts a closed-loop refrigerant oil temperature control system. The oil temperature is monitored in real time by a PLC controller, and the refrigerant flow is precisely controlled by adjusting the electronic expansion valve. The temperature control accuracy reaches ±1℃.

[0017] Analysis of the above technical content: This solution employs a dual-speed low-temperature meat grinder, pre-cooling the grinding barrel to -15℃, and innovatively adopts a closed-loop refrigerant oil temperature control system. A PLC controller monitors the oil temperature in real time, adjusting the electronic expansion valve to precisely control the refrigerant flow, achieving a temperature control accuracy of ±1℃. This design overcomes the shortcomings of traditional meat grinders, which lack precise temperature control or have low accuracy. The refrigerant oil, acting as a cold source, can efficiently exchange heat with the minced meat, creating a low-temperature environment in advance to ensure the absorption of mechanical friction heat during the subsequent grinding process. The dual-speed design adapts to the speed requirements of different grinding stages, avoiding problems such as insufficient protein dissolution or excessive denaturation caused by a single speed. This is the first time that industrial-grade precise temperature control technology (PLC control + electronic expansion valve adjustment) has been applied to meatball grinding equipment, solving the core pain point that traditional room-temperature or simple temperature control equipment cannot stably control the grinding temperature. It achieves precise temperature control throughout the grinding process, providing equipment support for the stable conversion of chilled pork protein.

[0018] Step 3: First grinding (salt dissolution stage), add the prepared minced meat to the pre-cooled grinding bucket, along with edible salt and compound phosphate, maintain the grinding temperature at 0-2℃, and grind at a low speed of 70-100r / min for 10-15 minutes. During the pounding process, the efficient heat exchange between the refrigerant oil and the minced meat allows for the real-time absorption of heat generated by mechanical friction, ensuring that the temperature of the minced meat remains stable at 0-2℃ during the salting stage. This promotes the full dissolution of myofibril proteins, forming a uniform protein solution and laying the foundation for gel formation.

[0019] Analysis of the above technical content: This solution clearly defines the temperature range as 0-2℃, the rotation speed as 70-100 r / min, and the time as 10-15 minutes for the first grinding stage. Simultaneously, through efficient heat exchange between the refrigerant oil and the minced meat, heat generated by mechanical friction is absorbed in real time, ensuring stable temperature during the salt-dissolving stage. In principle, this temperature range avoids both low temperatures inhibiting ion activity and high temperatures causing excessive protein denaturation. The low-speed grinding provides sufficient time for ion penetration, allowing the Na⁺ and Cl⁻ released from the edible salt to enter the protein double layer, neutralizing negative charges and disrupting the hydration layer, thus fully dissolving myofibril proteins. The complex phosphate further enhances the protein dissolution effect, forming a homogeneous protein solution. This step is the first to precisely quantify the temperature, rotation speed, and time parameters of the salt-dissolving stage. Combined with refrigerant oil temperature control technology, it solves the problems of temperature control issues and incomplete protein dissolution during the salt-dissolution stage in traditional processes. It achieves efficient dissolution of myofibril proteins (accounting for 60-70% of muscle protein), laying a solid foundation for the subsequent formation of the gel network, which is the core guarantee for the elastic texture of the meatballs.

[0020] Step 4: Secondary grinding (addition of auxiliary materials stage), increase the grinding blade speed to a high speed of 120-150 r / min, maintain the temperature at 0-2℃, and slowly add phosphate distarch, white sugar, fried garlic, fried shallots, white pepper powder, compound seasoning and sterile ice water to the grinding bucket. Grind at high speed for 15-20 minutes, and check the temperature every 5 minutes during this period to ensure that the temperature is ≤12℃.

[0021] Analysis of the above technical content: This solution involves a second grinding process, increasing the rotation speed to a high speed of 120-150 r / min, maintaining a temperature of 0-2℃, and checking the temperature every 5 minutes to ensure it is ≤12℃. Simultaneously, phosphate distarch, spices, compound seasonings, and sterile ice water at 0-2℃ are slowly added, followed by high-speed grinding for 15-20 minutes. The high-speed rotation generates strong shear force, ensuring thorough and uniform mixing of the ingredients and the minced meat, preventing localized flavor imbalances or molding defects. The addition of sterile ice water not only regulates the moisture content of the minced meat but also absorbs the frictional heat generated during high-speed grinding, providing double protection against excessive temperature fluctuations and protein denaturation. At this stage, phosphate distarch binds to proteins through hydrogen bonds, enhancing the strength and stability of the subsequent gel. This innovative step employs a combination of "high-speed mixing + low-temperature temperature control + intermittent monitoring," which solves the quality fluctuation problems caused by uneven mixing of auxiliary materials and excessively rapid heating during pounding in traditional processes. It achieves a balance between maximizing the function of auxiliary materials and ensuring the stability of the minced meat, thereby enhancing the flavor profile of the meatballs while also guaranteeing the juiciness and shapeability of the meat.

[0022] Step 5: Three rounds of pounding (gel formation stage). Reduce the speed to a low speed of 70-100 r / min, keep the temperature ≤12℃, and continue pounding for 5 minutes until the minced meat forms a uniform, delicate, and glossy gel-like consistency. It should also be elastic to the touch and not sticky. This is the end point of the pounding process. During the gel formation stage, slow-speed pounding promotes the interaction of hydrophobic groups in proteins, forming a stable and dense gel network. At the same time, an infrared temperature monitor is used to monitor the temperature of the minced meat in real time, accurately controlling the pounding endpoint to avoid excessive pounding that could damage the gel structure and ensure the elasticity and shaping stability of the meatballs.

[0023] Analysis of the above technical content: This solution involves three rounds of pounding at a low speed of 70-100 r / min, maintaining a temperature ≤12℃, and continuously pounding for 5 minutes until the meat paste forms a uniform, delicate, and glossy gel-like consistency that is elastic to the touch and not sticky. From a theoretical perspective, low-speed pounding promotes the interaction of exposed hydrophobic groups after the dissolved myofibril proteins unfold, forming a stable and dense gel network. Simultaneously, it avoids high-speed shear forces damaging the initially formed gel structure. Real-time monitoring with an infrared temperature monitor enables precise determination of the pounding endpoint, preventing over-pounding that could lead to a loose gel structure. This step is the first to clearly define the rotation speed, temperature, and endpoint judgment criteria for the gel formation stage, breaking through the traditional, experience-based, and crude method of judging the pounding endpoint. It solves the problems of unstable gel structure and insufficient elasticity in meatballs, achieving a precise conversion from protein solution to gel-like meat paste, ensuring the core quality of a chewy and bouncy texture in the meatballs.

[0024] Step 6: Low-temperature molding and water bath curing. Place the gel-like minced meat into a molding machine to form spherical blanks with a diameter of 3-3.5cm. Then place them into a flowing water bath and heat to 55℃ at a rate of 1℃ / min and hold for 3 minutes. Then heat to 75-80℃ at the same rate and hold for 2 minutes (ensure the center temperature is ≥70℃). Finally, heat to 90-95℃ at a rate of 1℃ / min and cure for 4 minutes. The flowing water bath uses a segmented temperature control system. Through high-precision temperature sensors and automatic temperature control devices, the heating rate is strictly controlled at 1℃ / min to ensure that the protein gradually coagulates, activates transglutaminase activity, improves the strength and taste stability of the meatball gel, and avoids quality defects caused by temperature fluctuations.

[0025] Analysis of the above technical content: This solution uses low-temperature molding to form gel-like minced meat into 3-3.5cm spherical blanks, suitable for heat transfer during subsequent water bath cooking; the water bath cooking uses a flowing water bath tank, with segmented heating at a rate of 1℃ / min (55℃ for 3 minutes → 75-80℃ for 2 minutes → 90-95℃ for 4 minutes), ensuring a core temperature ≥70℃. The segmented, slow heating design allows the proteins in the minced meat to gradually coagulate, avoiding excessive internal and external temperature differences and gel structure rupture caused by rapid heating; the 55℃ holding temperature activates endogenous transglutaminase in the minced meat, promoting protein cross-linking and enhancing gel strength; the 75-80℃ holding temperature ensures the core temperature reaches the target, killing potential microorganisms; and the 90-95℃ cooking temperature allows flavor substances to fully integrate, enhancing the richness of the taste. This innovative step employs segmented temperature-controlled water bath technology, overcoming the defects of traditional direct boiling in boiling water that result in an outside that is cooked but an inside that is raw, and a dry texture. It solves the problem of unstable quality during the cooking process and achieves simultaneous improvement in shaping stability, microbial safety, and flavor harmony.

[0026] Step 7: Post-processing. The cooked meatballs are taken out and quickly cooled to a surface temperature of <15℃ by a conveyor belt air cooling system and the surface water droplets are blown away. Then they are placed in a quick-freezing tunnel at -35 to -40℃ and quick-frozen for 30 to 40 minutes with an air speed of 3-5m / s to lower the core temperature to below -18℃. After that, they are packaged and refrigerated for storage. The quick-freezing tunnel uses a fluidized bed conveying method, where the meatballs are suspended and tumbled by the upward airflow from the bottom, ensuring that each meatball is evenly exposed to the low-temperature air, freezing quickly without sticking together. At the same time, it is equipped with a variable frequency wind speed control system, which dynamically adjusts the wind speed according to the freezing state of the meatballs to prevent the ice crystals from being too large and damaging the meat structure, thus preserving the nutrition and taste to the maximum extent.

[0027] Analysis of the above technical content: In this solution, the meatballs are first rapidly cooled to a surface temperature <15℃ and water droplets are dispersed using a conveyor belt air-cooling system. They are then placed in a -35 to -40℃ quick-freezing tunnel and quick-frozen for 30-40 minutes at a wind speed of 3-5 m / s, lowering the core temperature to below -18℃. Rapid air cooling quickly removes residual heat from the surface of the meatballs, preventing further denaturation and dispersing surface water droplets to prevent excessive frost formation after freezing. The quick-freezing tunnel uses a fluidized bed conveyor system; the upward airflow from the bottom suspends and tumbles the meatballs, ensuring each meatball is evenly exposed to the low-temperature air. Combined with a variable frequency fan speed control system that dynamically adjusts the fan speed, rapid freezing without sticking is achieved, preventing excessively large ice crystals from damaging the meat structure. This step is the first to combine "rapid air cooling + fluidized bed quick freezing + variable frequency air speed control" in the post-processing of meatballs, solving the problems of large ice crystals, meatball sticking and nutrient loss in the traditional freezing process. It achieves complete preservation of meat structure and extends product shelf life (up to 12 months), providing a guarantee for the long-term storage and circulation of meatballs.

[0028] Regarding the working principle of this solution: This solution primarily utilizes precise temperature control and a segmented grinding process in synergy, combined with optimized raw material characteristics and upgraded post-processing technologies, to achieve high-quality preparation of chilled pork meatballs. In the raw material pretreatment stage, chilled pork hind leg meat is selected 24-48 hours after slaughter, with the temperature controlled between 0-4℃. This temperature and time range ensures the pork is in the late rigor mortis stage, with a stable pH value of 5.5-6.5 and myofibril protein activity maintained at a high level, laying the foundation for subsequent protein dissolution. The meat is then cleaved, cut into pieces, and ground into 6-8mm particle size mince. This ensures the mince's looseness facilitates ion penetration while preventing premature protein denaturation due to excessively small particle size.

[0029] The pre-cooling stage of the pounding equipment employs a dual-speed low-temperature pounding machine. A closed-loop refrigerant oil temperature control system pre-cools the pounding tank to -15℃. A PLC controller monitors the oil temperature in real time and adjusts the electronic expansion valve to precisely control the refrigerant flow, achieving a temperature control accuracy of ±1℃. The refrigerant oil and minced meat undergo efficient heat exchange, absorbing heat generated by mechanical friction in real time, thus creating a stable low-temperature environment. During the first pounding stage (salt dissolution stage), a low temperature of 0-2℃ and a low speed of 70-100 r / min are maintained. The Na⁺ and Cl⁻ released from the edible salt enter the protein double layer, neutralizing the negative charge and disrupting the hydration layer. The complex phosphate (sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate mixed in a 1:2:1 mass ratio) chelates metal ions and adjusts the pH value. These two components synergistically promote the complete dissolution of myofibrillar proteins, forming a homogeneous protein solution.

[0030] The second grinding stage (addition of auxiliary materials) involves increasing the rotation speed to 120-150 rpm at high speed, maintaining a temperature of 0-2℃. The added distarch phosphate binds to the protein through hydrogen bonds, enhancing gel stability. Sterile ice water at 0-2℃ is used to regulate humidity and assist in temperature control. High-speed shearing ensures thorough mixing of the auxiliary materials and minced meat. Temperature is monitored every 5 minutes to ensure it remains ≤12℃, preventing excessive protein denaturation. The third grinding stage (gel formation stage) returns to a low speed of 70-100 rpm, maintaining a temperature ≤12℃. Real-time monitoring with an infrared temperature monitor promotes the interaction of hydrophobic groups in the proteins, forming a stable and dense gel network.

[0031] After low-temperature molding, the meatballs are heated in stages at a rate of 1℃ / min (55℃ for 3 minutes → 75-80℃ for 2 minutes → 90-95℃ for 4 minutes). High-precision temperature sensors and automatic temperature control devices ensure stable heating, gradually activating transglutaminase activity, promoting protein cross-linking, and killing microorganisms. In the post-processing stage, a conveyor belt air-cooling system rapidly cools the meatballs to a surface temperature <15℃. A -35 to -40℃ quick-freezing tunnel, combined with fluidized bed conveying and variable frequency air speed control (3-5m / s), lowers the center temperature of the meatballs to below -18℃ within 30-40 minutes, preventing excessive ice crystals from damaging the meat structure and achieving quality preservation and long-term storage.

[0032] The core innovation of this solution lies in: A comprehensive low-temperature precision temperature control preparation system tailored to the characteristics of chilled pork is proposed, solving four core problems in traditional meatball preparation processes: severe meat denaturation, nutrient loss, high risk of microbial growth, and poor raw material adaptability. Traditional processes rely on frozen pork, and grinding at room temperature or without temperature control leads to excessive protein denaturation and a tough texture. High temperatures accelerate nutrient loss and easily promote microbial growth. Chilled pork is difficult to apply due to its poor process adaptability.

[0033] Simultaneously, for the first time, a closed-loop refrigerant oil temperature control system was combined with a PLC controller and electronic expansion valve and applied to the meatball crushing equipment, achieving precise temperature control of ±1℃ throughout the crushing process, overcoming the limitations of insufficient temperature control accuracy in traditional equipment. A three-stage crushing process was designed for the first time, clearly defining the temperature (0-2℃ for the first stage, 0-2℃ for the second stage, and ≤12℃ for the third stage), rotation speed (70-100r / min for the first stage, 120-150r / min for the second stage, and 70-100r / min for the third stage), and time parameters for each stage. Combined with an infrared temperature monitor, the crushing endpoint was precisely controlled, achieving the orderly transformation of myofibril proteins from dissolution to gel formation. For the first time, a segmented water bath curing technology (heating rate of 1℃ / min) and fluidized bed quick-freezing were employed. The post-processing combination with variable frequency wind speed control solves the industry pain points of uneven cooking and large frozen ice crystals; for the first time, the special raw material ratio of chilled pork is optimized, and auxiliary materials such as compound phosphate and phosphate ester double starch are specifically matched, breaking through the dependence of traditional processes on frozen pork and realizing the stable application of chilled pork in meatball preparation.

[0034] Technical effects of implementing this solution: A qualitative leap has been achieved in taste and quality. Through a low-temperature pounding process maintained at ≤12℃ throughout, especially the precise temperature control design of pre-cooling the pounding bucket to -15℃, excessive denaturation of pork protein is effectively avoided. Myofibril proteins are fully dissolved and form a stable and dense gel network, resulting in meatballs with excellent elasticity. They are juicy and plump when chewed, neither dry nor hard, with a texture close to high-quality handmade meatballs. This completely solves the core defects of traditionally made meatballs, such as being too hard, lacking elasticity, and lacking juiciness. The segmented pounding process ensures more even mixing of auxiliary ingredients and minced meat, fully releasing the flavors of spices such as fried garlic, fried scallions, and white pepper powder. White sugar neutralizes the taste, resulting in meatballs with a rich and pure flavor profile, free of unpleasant odors.

[0035] In terms of nutrient preservation, the low-temperature environment significantly inhibits the activity of lipoxidase, reduces the decomposition and loss of water-soluble nutrients such as B vitamins, and avoids unpleasant flavor substances produced by fat oxidation. Compared with traditional processes, the nutritional value of meatballs is greatly improved. It retains the high-quality protein of chilled pork and reduces the loss of nutrients, achieving a balance between deliciousness and nutrition.

[0036] Food safety assurance has been significantly enhanced. The entire preparation process (pretreatment, crushing, and molding) is controlled within a low temperature range of 0-12℃, completely avoiding the dangerous microbial growth zone of 5-32℃ and significantly inhibiting the reproduction of bacteria and other microorganisms. Combined with subsequent rapid cooling (surface temperature <15℃) and deep quick-freezing process (quick freezing at -35 to -40℃ for 30-40 minutes, with a core temperature ≤-18℃), the shelf life of the product can be extended to 12 months under -18℃ freezing conditions. This significantly reduces the risk of microbial contamination and solves the problems of high food safety risks and short shelf life associated with traditional room temperature crushing processes, providing reliable assurance for product storage and market circulation.

[0037] Regarding process stability and raw material compatibility, this solution effectively addresses the issues of poor shape retention and easy breakage of chilled pork meatballs through precise temperature control, segmented crushing, and optimized proportioning. This reduces raw material loss and improves production efficiency. The successful application of chilled pork not only broadens the range of raw material choices for meatball preparation but also reduces the cost and quality loss associated with the thawing process compared to frozen pork. Furthermore, the parameters at each stage of the preparation process are clear and controllable, resulting in high product quality consistency. This avoids the quality instability issues caused by temperature fluctuations and insufficient raw material compatibility in traditional processes, demonstrating significant market competitiveness and value for large-scale production applications.

[0038] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A meatball based on low-temperature pounding technology of chilled fresh pork, characterized in that: The following ingredients are included in the following proportions by weight percentage: 70-72% chilled pork hind leg meat (fat content ≤5%), 18-20% medium fat (8mm), 1.0-1.5% edible salt, 1-1.5% white sugar, 0.2-0.3% garlic chips, 0.3-0.5% compound phosphates (sodium hexametaphosphate, sodium pyrophosphate, and sodium tripolyphosphate mixed in a mass ratio of 1:2:1), 0.3-0.4% phosphate distarch, 0.2-0.3% fried shallots, 0.4-0.5% white pepper powder, 1.5-2.0% compound seasonings, and 2-2.3% sterile ice water at 0-2℃.

2. The method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork according to claim 1, characterized in that: The preparation method is as follows: Step 1: Raw material pretreatment. Select fresh pork hind leg meat that has been slaughtered for 24-48 hours and is kept at a temperature of 0-4℃. After the fascia is cut off by a slicer, cut the meat into 5-8cm square pieces and put them into a meat grinder to grind into minced meat with a particle size of 6-8mm. Set aside. Step 2: Pre-cooling the crushing equipment. Pre-cool the crushing barrel of the dual-speed low-temperature crusher to -15℃. The equipment adopts a closed-loop refrigerant oil temperature control system. The oil temperature is monitored in real time by a PLC controller, and the refrigerant flow is precisely controlled by adjusting the electronic expansion valve. The temperature control accuracy reaches ±1℃. Step 3: First grinding (salt dissolution stage), add the prepared minced meat to the pre-cooled grinding bucket, along with edible salt and compound phosphate, maintain the grinding temperature at 0-2℃, and grind at a low speed of 70-100r / min for 10-15 minutes. Step 4: Secondary grinding (addition of auxiliary materials stage), increase the grinding blade speed to a high speed of 120-150 r / min, maintain the temperature at 0-2℃, and slowly add phosphate distarch, white sugar, fried garlic, fried shallots, white pepper powder, compound seasoning and sterile ice water to the grinding bucket. Grind at high speed for 15-20 minutes, and check the temperature every 5 minutes during this period to ensure that the temperature is ≤12℃. Step 5: Three rounds of pounding (gel formation stage). Reduce the speed to a low speed of 70-100 r / min, keep the temperature ≤12℃, and continue pounding for 5 minutes until the minced meat forms a uniform, delicate, and glossy gel-like consistency. It should also be elastic to the touch and not sticky. This is the end point of the pounding process. Step 6: Low-temperature molding and water bath curing. Place the gel-like minced meat into a molding machine to form spherical blanks with a diameter of 3-3.5cm. Then place them into a flowing water bath and heat to 55℃ at a rate of 1℃ / min and hold for 3 minutes. Then heat to 75-80℃ at the same rate and hold for 2 minutes (ensure the center temperature is ≥70℃). Finally, heat to 90-95℃ at a rate of 1℃ / min and cure for 4 minutes. Step 7: Post-processing. The cooked meatballs are taken out and quickly cooled to a surface temperature of <15℃ by a conveyor belt air cooling system and the surface water droplets are blown away. Then they are placed in a quick-freezing tunnel at -35 to -40℃ and quick-frozen for 30 to 40 minutes with an air speed of 3-5m / s to lower the core temperature to below -18℃. After that, they are packaged and refrigerated for storage.

3. The method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork according to claim 2, characterized in that: In step 3, the efficient heat exchange between the refrigerant oil and the minced meat during the pounding process absorbs the heat generated by mechanical friction in real time, ensuring that the temperature of the minced meat is stable at 0-2℃ during the salting stage. This promotes the full dissolution of myofibril protein, forming a uniform protein solution and laying the foundation for gel formation.

4. The method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork according to claim 2, characterized in that: In step 5, the gel formation stage promotes the interaction of hydrophobic groups of proteins through slow pounding, forming a stable and dense gel network. At the same time, an infrared temperature monitor is used to monitor the temperature of the minced meat in real time, accurately control the pounding endpoint, avoid excessive pounding which would damage the gel structure, and ensure the elasticity and shaping stability of the meatballs.

5. The method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork according to claim 2, characterized in that: In step 6, the flow bath uses a segmented temperature control system. Through a high-precision temperature sensor and an automatic temperature control device, the heating rate is strictly controlled at 1℃ / min to ensure that the protein gradually coagulates, activates the activity of transglutaminase, improves the strength and taste stability of the meatball gel, and avoids quality defects caused by temperature fluctuations.

6. The method for preparing meatballs based on low-temperature pounding technology of chilled fresh pork according to claim 2, characterized in that: In step 7, the quick-freezing tunnel uses a fluidized bed conveying method, in which the meatballs are suspended and tumbled by the upward airflow from the bottom, ensuring that each meatball is evenly exposed to the low-temperature air, freezes quickly and does not stick together. At the same time, it is equipped with a variable frequency wind speed control system to dynamically adjust the wind speed according to the freezing state of the meatballs, so as to avoid the ice crystals being too large and damaging the meat structure, and to preserve the nutrition and taste to the maximum extent.