Method for improving local black pig pork flavor based on microbial fermentation

Abstract

The invention discloses a local black pig pork flavor improvement method based on microbial fermentation, and relates to the technical field of microbial fermentation, and the method comprises the following specific steps: raw material pretreatment, enzymolysis treatment, low-salt pickling, sectional dynamic fermentation and post-treatment. The pork can be subjected to mild enzymolysis through neutral protease, micropores are formed in the surface of a pork matrix to expand microbial action sites, then the pork subjected to enzymolysis is treated through the compounded low-salt pickling liquid, salt in the low-salt pickling liquid can construct a low-permeability environment to inhibit infectious microbe colonization, and then the pork is subjected to enzymolysis; the white granulated sugar can provide a carbon source for subsequent strain metabolism, the composite phosphate can maintain the structural stability of muscle protein, the vitamin C can delay oxidation of myoglobin, the whole set of treatment process can achieve synchronous achievement of matrix modification, infectious microbe inhibition and matrix protection, and a stable early-stage foundation is built for subsequent fermentation. And the strain can start metabolism on a clean matrix with multiple acting sites.

Description

Technical Field

[0001] This invention relates to the field of microbial fermentation technology, specifically to a method for improving the flavor of local black pig pork based on microbial fermentation. Background Technology

[0002] Local black pigs are a superior native breed developed through long-term selective breeding. With their firm meat and even distribution of intramuscular fat, they have a unique competitive advantage in the high-end meat product market and are highly favored by consumers who pursue the original flavor of ingredients. As residents' meat consumption upgrades, they place higher demands on the flavor diversity and eating experience of local black pig pork products. Related processing industries are also ushering in industry opportunities for quality upgrading. However, their natural muscle fiber characteristics also bring certain challenges to subsequent processing. The market's demand for flavor improvement technologies that are adapted to their characteristics is becoming increasingly urgent.

[0003] However, existing technologies for flavor improvement of local black pig pork mostly employ single fermentation or simple enzymatic hydrolysis and curing processes, without forming a synergistic pretreatment system. During direct fermentation, the number of microbial sites in the pork matrix is ​​limited, resulting in insufficient conversion of flavor substances. Enzymatic hydrolysis alone can easily damage the meat structure, while low-salt curing alone cannot provide favorable matrix conditions for subsequent fermentation. At the same time, traditional fermentation is mostly based on a single temperature mode, which cannot take into account the proliferation of microorganisms, flavor accumulation, and meat quality preservation. This can easily lead to spoilage caused by the growth of miscellaneous bacteria, or the meat may become loose due to excessive protease action, making it difficult to achieve a balanced optimization of flavor and meat quality. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for improving the flavor of local black pig pork based on microbial fermentation. This invention uses neutral protease to gently enzymatically hydrolyze pork, forming micropores on the surface of the pork matrix to expand the microbial action sites. Then, the enzymatically hydrolyzed pork is treated with a compound low-salt curing solution. The salt in the low-salt curing solution can create a hypotonic environment to inhibit the colonization of miscellaneous bacteria, white sugar can provide a carbon source for subsequent microbial metabolism, compound phosphate can maintain the stability of muscle protein structure, and vitamin C can delay myoglobin oxidation. The entire process can achieve simultaneous matrix modification, microbial inhibition, and matrix protection, laying a stable foundation for subsequent fermentation and allowing microorganisms to initiate metabolism on a clean matrix with multiple action sites.

[0005] To solve the above-mentioned technical problems, this invention provides the following technical solution: a method for improving the flavor of local black pig pork based on microbial fermentation, the specific steps of which are as follows: Raw material pretreatment: Select local black pig pork, remove visible fat and connective tissue, and cut the processed pork into chunks; Enzymatic hydrolysis: Prepare a protease solution, spray the protease solution evenly on the surface of the pork chunks, and then place the pork under specific conditions for enzymatic hydrolysis; Low-salt curing: Prepare a low-salt curing solution, apply the solution evenly to the surface of the enzymatically hydrolyzed pork, and then place the pork under specific conditions for curing. Segmented dynamic fermentation: Prepare fermentation starter, inoculate the fermentation starter onto the surface of the marinated pork, and then put the pork into the fermentation equipment for fermentation in stages; Post-processing: After fermentation is complete, open the fermentation equipment and take out the pork. Wipe the surface of the pork with sterile gauze to remove any fermentation residues. Then, vacuum pack the pork.

[0006] Furthermore, in the raw material pretreatment, cutting the treated pork into chunks specifically involves cutting it into rectangular blocks of 3cm×3cm×2cm-5cm×5cm×3cm.

[0007] Furthermore, in the enzymatic hydrolysis process, the steps for preparing the protease solution are as follows: a neutral protease with an enzyme activity of 10,000-15,000 U / g is selected, and the neutral protease is dissolved in distilled water to prepare a protease solution with a mass concentration of 0.8-1.2%; the steps for uniformly spraying the protease solution are as follows: 8-12 mL of protease solution is sprayed per 100g of pork chunks; the steps for enzymatic hydrolysis under specific conditions are as follows: the pork after being sprayed with the protease solution is placed at 20-25℃ for 1.5-2 hours for enzymatic hydrolysis.

[0008] Furthermore, in the enzymatic hydrolysis process, the pH value is dynamically controlled simultaneously: when preparing a protease solution with a mass concentration of 0.8-1.2%, the pH value of the protease solution is adjusted to 7.0-7.5 using sterile hydrochloric acid or sodium hydroxide solution; after 0.5-0.7 hours of enzymatic hydrolysis, the pH value of the pork surface is detected every 0.3-0.4 hours using a sterile surface pH meter, and the pH value of the pork surface is maintained at 7.0-7.2 by adding sterile phosphate buffer with a concentration of 0.1-0.2 mol / L.

[0009] Furthermore, in the low-salt curing process, the steps for preparing the low-salt curing solution are as follows: according to the mass fractions, take 2-3 parts of salt, 1-1.5 parts of white sugar, 0.3-0.5 parts of compound phosphate, 0.05-0.1 parts of vitamin C, and 10-15 parts of water, mix thoroughly and stir until completely dissolved to obtain the low-salt curing solution; the step of evenly applying the low-salt curing solution is as follows: apply 10-15g of low-salt curing solution to every 100g of enzymatically hydrolyzed pork; the step of curing under specific conditions is as follows: place the pork coated with the low-salt curing solution into a sterile preservation box and cure at 4-6℃ for 8-10 hours.

[0010] Furthermore, in the segmented dynamic fermentation, the step of preparing the fermentation strain is as follows: Lactobacillus plantarum and Saccharomyces cerevisiae are mixed in a mass ratio of 2.7:1-3.3:1 to obtain the fermentation strain.

[0011] Furthermore, in the segmented dynamic fermentation, the inoculation step of the fermentation strain is as follows: the fermentation strain is inoculated into sterile physiological saline, stirred to make a uniform and non-agglomerated bacterial suspension, and then the bacterial suspension is evenly sprayed on the surface of the cured pork at an inoculation amount of 0.02-0.05% of the weight of the cured pork.

[0012] Furthermore, in the segmented dynamic fermentation, the fermentation process is carried out in stages as follows: the pork after being sprayed with bacterial suspension is placed in a fermentation device, which is a fermentation box equipped with a temperature sensor, a humidity sensor, and a temperature and humidity control unit. The first stage is carried out at 15-20℃ and 75-80% relative humidity. The second stage is carried out at 25-30℃ and 80-85% relative humidity. The third stage is carried out at 10-12℃ and 70-75% relative humidity.

[0013] Furthermore, in the segmented dynamic fermentation, the first stage of fermentation takes 22-26 hours, the second stage takes 46-50 hours, and the third stage takes 70-74 hours. During the fermentation process, the pork is turned over every 9-15 hours.

[0014] Furthermore, in the post-processing, the step of vacuum packaging the pork is as follows: the wiped pork is placed in a food-grade vacuum packaging bag, and the pork is sealed using a vacuum packaging machine with a vacuum degree of -0.095 to -0.1 MPa.

[0015] Compared with existing technologies, this method for improving the flavor of local black pig pork based on microbial fermentation has the following beneficial effects: I. This invention utilizes neutral protease to gently enzymatically hydrolyze pork, forming micropores on the surface of the pork matrix to expand the microbial action sites. The hydrolyzed pork is then treated with a compound low-salt curing solution. The salt in the low-salt curing solution creates a hypotonic environment to inhibit the colonization of miscellaneous bacteria, the white sugar provides a carbon source for subsequent microbial metabolism, the compound phosphate maintains the stability of muscle protein structure, and the vitamin C delays myoglobin oxidation. The entire process achieves simultaneous matrix modification, microbial inhibition, and matrix protection, laying a stable foundation for subsequent fermentation and allowing microorganisms to initiate metabolism on a clean matrix with multiple action sites.

[0016] II. This invention involves inoculating a mixed strain of Lactobacillus plantarum and Saccharomyces cerevisiae in a specific ratio onto the surface of treated pork, and then using a gradient temperature and humidity to control the fermentation process in stages. The low-temperature stage allows the strain to slowly adapt to the substrate environment and form a dominant microbial community. The medium-temperature stage activates the strain to secrete proteases and lipases, which decompose myofibrillar proteins and triglycerides to generate flavor precursors. The low-temperature maturation stage promotes the esterification reaction of flavor substances. At the same time, the turning during the fermentation process ensures uniform fermentation in all parts of the substrate. The entire fermentation process can match the metabolic rhythm of the strain with the generation and integration of flavor substances, allowing the pork substrate to complete the hierarchical accumulation of flavor while retaining its structural integrity.

[0017] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0019] Figure 1 A flowchart of a method for improving the flavor of local black pig pork based on microbial fermentation; Figure 2 A framework diagram of a method for improving the flavor of local black pig pork based on microbial fermentation; Figure 3 This is a flowchart of the segmented dynamic fermentation process in a method for improving the flavor of local black pig pork based on microbial fermentation. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0021] Example 1: In a small-batch pilot production scenario, using a method to improve the flavor of local black pig pork based on microbial fermentation, in the aseptic operating area of ​​the meat product R&D center, operators wearing aseptic work clothes, gloves, and masks retrieved 10 kg of fresh local black pig tenderloin from the cold chain storage. A sterile, leak-proof mat was laid on the operating table. First, visible fat and connective tissue from the surface and intermuscular spaces were removed piece by piece, using sterile tweezers to assist in the separation. Then, using sterilized stainless steel knives, the processed tenderloin was cut into 3cm × 3cm × 2cm rectangular blocks. Figure 1 As shown, the cut meat pieces are neatly placed in sterile stainless steel containers and temporarily stored in a 10°C transfer refrigerator for later use.

[0022] In the solution preparation area, a neutral protease with an enzyme activity of 10000 U / g was selected as the enzymatic hydrolysis reagent. First, 8g of neutral protease was weighed using an electronic balance. Then, 992mL of sterile distilled water was poured into a sterile glass mixing jar and stirred at low speed. Simultaneously, the neutral protease powder was slowly added to the water, and stirring continued for 10 minutes until the powder was completely dissolved. The pH value of the solution was then measured using a sterile pH meter and adjusted to 7.0 with sterile hydrochloric acid solution, preparing a 0.8% protease solution. The protease solution was then transferred to a sterile quantitative sprayer. Meat pieces were removed from the transfer container in batches and evenly spread on a sterile operating table. Following a ratio of 8mL of protease solution per 100g of pork, each piece was thoroughly sprayed, ensuring no area was missed. After spraying, the meat pieces were returned to the transfer container and transferred to a constant temperature incubator. The incubator temperature was adjusted to 20℃. In this closed environment without external airflow disturbance, the meat pieces underwent enzymatic hydrolysis for 1.5 hours. Figure 2 As shown, after 0.5 hours of enzymatic hydrolysis, the pH value was measured every 0.3 hours by lightly touching the surface of the meat block with a sterile surface pH meter. The pH value of the pork surface was stabilized at 7.0 by adding 0.1 mol / L sterile phosphate buffer, ensuring that the neutral protease could function in the optimal pH environment.

[0023] In the marinade preparation area, the raw materials are first weighed according to their respective weight proportions: 2 parts salt, 1 part white sugar, 0.3 parts compound phosphate, 0.05 parts vitamin C, and 10 parts water. Based on the processing scale of 10 kg of enzymatically hydrolyzed pork, the specific weights of each raw material are then determined as follows: 100 g salt, 50 g white sugar, 15 g compound phosphate, 2.5 g vitamin C, and 500 g water. These raw materials are then sequentially added to a sterile stainless steel mixing tank and stirred for 10 minutes until all raw materials are completely dissolved. A uniform and transparent low-salt marinade is formed. Then, the enzymatically hydrolyzed meat pieces are removed from the incubator. Using a sterile silicone brush, 10g of low-salt marinade is applied evenly to the surface of the meat pieces, according to the ratio of 10g of low-salt marinade to 100g of enzymatically hydrolyzed pork. The coated meat pieces are then placed in layers into sterile preservation boxes lined with breathable sterile gauze. The sterile preservation boxes are then moved into a 4°C refrigerated marinating cabinet for 10 hours of marinating in this stable temperature environment. The cabinet door is not opened during the marinating period to maintain environmental stability.

[0024] In the inoculum preparation room, 2.7g of *Lactobacillus plantarum* and 1g of *Saccharomyces cerevisiae* were weighed and placed in the same sterile Erlenmeyer flask. The flask was gently shaken to thoroughly mix the inoculum, resulting in a fermentation mixture with a mass ratio of 2.7:1. 500mL of sterile physiological saline was added to the flask, and the mixture was stirred for 15 minutes using a sterile magnetic stirrer to prepare a uniform, non-agglomerated bacterial suspension. Based on the actual weight of the cured pork, an inoculum rate of 0.02% was determined, requiring 20mL of the bacterial suspension to be sprayed. The bacterial suspension was transferred to a sterile sprayer and sprayed thoroughly onto the cured pork pieces. The pork pieces were then transferred to… The meat is transferred to a fermentation chamber equipped with a temperature sensor, humidity sensor, and temperature and humidity control unit. The fermentation chamber is first set to 15°C and 75% relative humidity for 22 hours for the first stage of fermentation. After the first stage, the fermentation chamber is set to 25°C and 80% relative humidity for 46 hours for the second stage of fermentation. After the second stage, the temperature is set to 10°C and 70% relative humidity for 70 hours for the third stage of low-temperature maturation fermentation. Throughout the fermentation process, the operator opens the fermentation chamber door every 9 hours and gently turns the meat pieces with sterile tools to ensure a consistent fermentation environment for all parts.

[0025] After the third stage of fermentation is completed, the fermentation box emits a beeping sound. The operator opens the fermentation box door and takes out all the meat pieces, placing them on a sterile workbench. Using sterile gauze, the operator gently wipes away the fermentation residues adhering to the surface of the meat pieces, controlling the pressure to avoid damaging the meat fiber structure. The wiped meat pieces are then placed one by one into a food-grade vacuum packaging bag. After the packaging bag passes the sterility test, it is sent to the vacuum packaging machine, which is set to a vacuum degree of -0.095MPa. The vacuum packaging machine is started to complete the vacuum sealing packaging. The packaged product is transferred to the finished product temporary storage area, resulting in a small batch of experimental flavor-improved local black pork tenderloin.

[0026] In summary, using local black pig tenderloin as raw material, a small-batch experimental process for improving pork flavor was successfully completed in the aseptic operating environment of the meat product R&D center. First, the black pig tenderloin underwent standardized pretreatment, removing excess tissue and cutting it into regular pieces. Then, a neutral protease was used to prepare an enzymatic hydrolysate, which was sprayed evenly. The pieces were then placed under suitable conditions for enzymatic hydrolysis. Afterward, the hydrolyzed pieces were marinated in a low-salt curing solution. A microbial culture, a mixture of *Lactobacillus plantarum* and *Saccharomyces cerevisiae*, was inoculated onto the surface of the pieces. A multi-stage, gradient temperature and humidity fermentation process was employed, with the pieces being turned regularly to ensure uniform fermentation. Finally, the product underwent aseptic wiping and vacuum packaging to obtain the experimental flavor-improved product. The entire process strictly adhered to aseptic operating procedures and established process logic, providing reliable small-batch experimental data support for subsequent process validation work.

[0027] Example 2: In the pilot production of medium-batch industrialized products, and in the scenario of improving the flavor of local black pig pork based on microbial fermentation, 15kg of fresh local black pig hind leg meat is conveyed on the assembly line in the standardized aseptic production workshop of the meat processing plant. Operators use deboning and degreasing tools to complete the initial processing of the hind leg meat, separating large pieces of fat from connective tissue. The processed hind leg meat is sent to aseptic stainless steel meat cutting equipment, which cuts the hind leg meat into 5cm×5cm×3cm rectangular blocks according to the preset program. The cut meat blocks are uniform in size and have no broken edges. They are then uniformly collected into aseptic food-grade plastic turnover containers and temporarily stored in the workshop's transit cold storage at 8℃ for later use.

[0028] In the semi-automatic solution preparation section of the workshop, a neutral protease with an enzyme activity of 15000 U / g was selected. 18g of the protease was weighed using an electronic scale and added to 982mL of sterile distilled water. The mixing tank was started with a fixed-speed stirring program to completely dissolve the neutral protease. The pH value of the solution was then detected by an online pH detection component and adjusted to 7.5 with sterile sodium hydroxide solution, forming a protease solution with a mass concentration of 1.2%. The protease solution was transported to the quantitative spraying unit via sterile pipeline. Meat pieces in the transfer containers were delivered to the spraying station in batches, according to a dosage of 100... A 12 mL atomized solution was sprayed onto each piece of pork. The sprayed pork was then transferred to a constant-temperature enzymatic hydrolysis chamber, where the temperature was adjusted to 25°C. In this undisturbed, sealed environment, the pork underwent enzymatic hydrolysis for 1.5 hours. After 0.7 hours of hydrolysis, the pH value of the pork surface was measured every 0.4 hours using a sterile surface pH meter. The pH value of the pork surface was maintained at 7.2 by adding 0.2 mol / L sterile phosphate buffer, ensuring the stability of protease activity during the hydrolysis process.

[0029] On the semi-automatic marinade preparation line, the raw material ratio is first set according to the mass parts: 3 parts salt, 1.5 parts white sugar, 0.5 parts compound phosphate, 0.1 parts vitamin C, and 15 parts water. Then, considering the processing scale of 15 kg of enzymatically hydrolyzed pork, the specific mass of each raw material is determined to be 225 g salt, 112.5 g white sugar, 37.5 g compound phosphate, 7.5 g vitamin C, and 1125 g water. All raw materials are sequentially added to the mixing tank and stirred at low speed for 15 minutes. After the mixture is completely dissolved to form a uniform low-salt marinade, the enzymatically hydrolyzed meat pieces are sent to the marinating and coating station, which is equipped with a rotating sterile silicone brush roller. The low-salt marinade is applied evenly to the surface of the meat pieces at a rate of 15g per 100g of enzymatically hydrolyzed pork. The coated meat pieces are then layered and placed into sterile preservation boxes and sent to a 6℃ cold storage marinating room. The room is equipped with multiple temperature control probes, and the staff records the temperature every 2 hours to ensure that the ambient temperature does not fluctuate during the 8-hour marinating process.

[0030] In the bacterial culture preparation workshop, 3.3g of *Lactobacillus plantarum* and 1g of *Saccharomyces cerevisiae* were weighed and mixed at a mass ratio of 3.3:1 using a mixing device. Then, 800mL of sterile physiological saline was added to the mixing container, and the mixture was stirred for 20 minutes to prepare a uniform bacterial suspension without agglomeration. Based on the actual weight of the cured pork, an inoculation rate of 0.05% was determined, requiring 75mL of the bacterial suspension to be sprayed. The bacterial suspension was then evenly sprayed onto the surface of the cured pork pieces through a pipeline spraying assembly. Figure 3 As shown, the sprayed meat chunks are then placed in a fermentation chamber equipped with multiple temperature and humidity sensors and an independent temperature and humidity control unit. The fermentation chamber is first set to 20°C and 80% relative humidity for 26 hours for the first stage of fermentation. After the first stage, the fermentation chamber parameters are switched to 30°C and 85% relative humidity for 50 hours for the second stage of fermentation. After the second stage, the parameters are switched to 12°C and 75% relative humidity for 74 hours for the third stage of fermentation. Throughout the fermentation process, every 15 hours, staff wearing sterile equipment enter the workshop to turn the meat chunks using a mechanical turning rack to ensure a balanced fermentation environment in all parts of the meat.

[0031] Once fermentation is complete, the fermentation box beeps, and the meat chunks are removed from the fermentation box and transferred to the post-processing station. Sterile gauze is used to gently wipe away any fermentation residue from the surface of the meat chunks, maintaining their integrity throughout the process. The cleaned meat chunks are then manually placed one by one into food-grade vacuum packaging bags, which are then fed into a vacuum packaging machine. The vacuum level is set to -0.1 MPa, and the machine is started to complete the vacuum sealing. The packaged products are then uniformly transported to the finished product storage area for inspection, ultimately yielding a medium-batch, industrial-scale trial production of flavor-improved local black pig hind leg meat.

[0032] In summary, using local black pig hind leg meat as raw material, a medium-batch industrial-scale pilot production of pork flavor improvement was conducted in a standardized aseptic production workshop. The process relied on semi-automatic production equipment to advance each stage. First, the raw material was cleaned and cut into standardized pieces using tools and equipment. Then, a neutral protease was used to prepare an enzymatic hydrolysate, which was then quantitatively atomized and sprayed onto the meat pieces. The meat pieces were then placed in a stable environment to complete the enzymatic hydrolysis. Next, a low-salt curing solution was used to cure the meat pieces at a constant temperature. A mixed bacterial culture was then inoculated onto the surface of the meat pieces. A multi-stage, gradient temperature and humidity fermentation process was employed, with the meat pieces being turned periodically. Finally, aseptic wiping and vacuum packaging yielded the flavor-improved product for industrial-scale pilot production, ready for testing. This process is suitable for the actual needs of medium-batch production, balancing process stability and production efficiency, and laying a practical foundation for the large-scale implementation of the technology.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for improving the flavor of local black pig pork based on microbial fermentation, characterized in that, The specific steps of this method are as follows: Raw material pretreatment: Select local black pig pork, remove visible fat and connective tissue, and cut the processed pork into chunks; Enzymatic hydrolysis: Prepare a protease solution, spray the protease solution evenly on the surface of the pork chunks, and then place the pork under specific conditions for enzymatic hydrolysis; Low-salt curing: Prepare a low-salt curing solution, apply the solution evenly to the surface of the enzymatically hydrolyzed pork, and then place the pork under specific conditions for curing. Segmented dynamic fermentation: Prepare fermentation starter, inoculate the fermentation starter onto the surface of the marinated pork, and then put the pork into the fermentation equipment for fermentation in stages; Post-processing: After fermentation is complete, open the fermentation equipment and take out the pork. Wipe the surface of the pork with sterile gauze to remove any fermentation residues. Then, vacuum pack the pork.

2. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 1, characterized in that, In the raw material pretreatment, the processed pork is cut into blocks, specifically into rectangular blocks of 3cm×3cm×2cm-5cm×5cm×3cm.

3. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 1, characterized in that, In the enzymatic hydrolysis process, the steps for preparing the protease solution are as follows: a neutral protease with an enzyme activity of 10,000-15,000 U / g is selected, and the neutral protease is dissolved in distilled water to prepare a protease solution with a mass concentration of 0.8-1.2%; the steps for uniformly spraying the protease solution are as follows: 8-12 mL of protease solution is sprayed per 100g of pork chunks; the steps for enzymatic hydrolysis under specific conditions are as follows: the pork after being sprayed with the protease solution is placed at 20-25℃ for 1.5-2 hours for enzymatic hydrolysis.

4. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 3, characterized in that, During the enzymatic hydrolysis process, the pH value is dynamically controlled simultaneously: when preparing a protease solution with a mass concentration of 0.8-1.2%, the pH value of the protease solution is adjusted to 7.0-7.5 using sterile hydrochloric acid or sodium hydroxide solution; after 0.5-0.7 hours of enzymatic hydrolysis, the pH value of the pork surface is measured every 0.3-0.4 hours using a sterile surface pH meter, and the pH value of the pork surface is maintained at 7.0-7.2 by adding sterile phosphate buffer solution with a concentration of 0.1-0.2 mol / L.

5. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 1, characterized in that, The steps for preparing the low-salt curing solution are as follows: Take 2-3 parts salt, 1-1.5 parts white sugar, 0.3-0.5 parts compound phosphate, 0.05-0.1 parts vitamin C, and 10-15 parts water by weight, mix thoroughly and stir until completely dissolved to obtain the low-salt curing solution; The step of evenly applying the low-salt curing solution is as follows: Apply 10-15g of low-salt curing solution to every 100g of enzymatically hydrolyzed pork; The step of curing under specific conditions is as follows: Place the pork coated with the low-salt curing solution in a sterile preservation box and cure at 4-6℃ for 8-10 hours.

6. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 1, characterized in that, In the segmented dynamic fermentation, the steps for preparing the fermentation strain are as follows: Lactobacillus plantarum and Saccharomyces cerevisiae are mixed at a mass ratio of 2.7:1-3.3:1 to obtain the fermentation strain.

7. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 6, characterized in that, In the segmented dynamic fermentation, the inoculation steps of the fermentation strain are as follows: the fermentation strain is inoculated into sterile physiological saline, stirred to make a uniform and non-agglomerated bacterial suspension, and then the bacterial suspension is evenly sprayed on the surface of the cured pork at an inoculation amount of 0.02-0.05% of the weight of the cured pork.

8. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 7, characterized in that, In the segmented dynamic fermentation, the fermentation process is carried out in stages as follows: the pork after being sprayed with bacterial suspension is placed in a fermentation device, which is a fermentation box equipped with a temperature sensor, a humidity sensor and a temperature and humidity control unit. The first stage is carried out at 15-20℃ and 75-80% relative humidity. The second stage is carried out at 25-30℃ and 80-85% relative humidity. The third stage is carried out at 10-12℃ and 70-75% relative humidity.

9. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 1, characterized in that, In the segmented dynamic fermentation, the first stage of fermentation takes 22-26 hours, the second stage takes 46-50 hours, and the third stage takes 70-74 hours. During the fermentation process, the pork is turned over every 9-15 hours.

10. The method for improving the flavor of local black pig pork based on microbial fermentation according to claim 1, characterized in that, In the post-processing, the vacuum packaging step of the pork is as follows: the wiped pork is placed in a food-grade vacuum packaging bag, and the pork is sealed by a vacuum packaging machine with a vacuum degree of -0.095 to -0.1 MPa.

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