Processing method of household dry-type cooked yak meat

Abstract

The invention relates to the technical field of yak meat product processing, and discloses a household dry-type ripened yak meat processing method, which comprises: carrying out static liquid discharge treatment on fresh yak meat, loading into a polymer semipermeable membrane ripened bag, vacuumizing, and sealing, so that the bag body is attached to the surface of a meat sample under negative pressure; placing the packaged meat sample in an air-cooled refrigerator in an overhead manner by using a support frame, and ensuring that the periphery and the bottom of the meat sample are in contact with airflow for low-temperature ripening; performing turn-over treatment every 2-4 days in the ripening process; and after ripening, opening the bag and cutting off a hard shell layer on the surface. By limiting the water vapor transmission rate of the ripening bag and cooperating with a specific temperature, humidity and wind speed environment, the method disclosed by the invention realizes directional balanced migration of meat sample moisture in a family environment, improves the tenderness of the meat by virtue of endogenous enzymolysis, and weakens the mutton smell of yak meat. The method is simple and convenient to operate, the technical problems that the ripening is easy to decay and the dehydration is uneven in a household environment are effectively solved, and the prepared finished product is obvious in ripening flavor and convenient for subsequent storage.

Description

Technical Field

[0001] This invention relates to the field of yak meat product processing technology, specifically a method for processing dry-aged yak meat for home use. Background Technology

[0002] Yak meat boasts high nutritional value due to its high protein, low fat content, and abundance of functional amino acids, vitamins, and minerals. However, the harsh growing environment at high altitudes results in a long growth cycle for yaks, leading to slow muscle development and low fat deposition efficiency. This results in a relatively coarse and tough texture, less tenderness, and a pronounced gamey odor, significantly limiting its popularity in the high-end consumer market.

[0003] Dry aging, a processing technique for improving meat quality, involves prolonged aging of fresh meat under controlled conditions. This utilizes the biochemical action of endogenous enzymes to enhance tenderness and induce unique flavors. While dry aging shows significant potential in improving the texture and flavor of yak meat, it demands extremely high precision in environmental parameters. Traditional industrial aging typically relies on expensive temperature and humidity control equipment and specialized sterilization systems. These systems are bulky, energy-intensive, and complex to maintain, making them unsuitable for direct application in ordinary home environments.

[0004] When attempting dry aging using a household air-cooled refrigerator, the temperature and humidity inside the refrigerator fluctuate drastically due to the compressor's start-stop cycle and frequent door opening and closing, making it difficult to form a uniformly thick and protective dry crust on the surface of the meat sample. If the surface dehydration rate does not match the internal moisture migration, the meat sample is highly susceptible to deep-seated spoilage. Furthermore, household refrigerators often contain multiple types of food stored together, leading to a high risk of cross-contamination and a lack of effective physical protection and mass transfer balancing methods. Existing simple home processing methods generally suffer from excessive dry loss of meat samples, a high risk of microbial contamination, and incomplete development of aged flavor, failing to guarantee the food safety and quality stability of the finished product. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for processing home-use dry-aged yak meat, aiming to solve the problems of high risk of microbial contamination, excessive moisture loss leading to excessive dryness, and incomplete flavor development during the aging period in home-use dry-aged yak meat.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for processing household dry-aged yak meat, comprising the following steps: Fresh yak meat is subjected to static drainage treatment until no obvious liquid flows out from the surface of the meat sample. After draining, the yak meat is placed into aging bags and vacuum-sealed to ensure that the aging bags adhere to the surface of the meat sample under negative pressure. The packaged meat sample was placed in an air-cooled refrigerator and supported by a support frame so that the sides and bottom of the meat sample were in contact with the airflow for low-temperature maturation. During the aging process, the meat samples are turned over periodically to ensure that the surface of the meat samples is in uniform contact with the air-cooled airflow; After aging, the aging bag is removed, and the hardened outer layer of the meat sample that has dried and changed color is cut off to obtain home-cooked dry-aged yak meat.

[0007] By employing the above technical solution, this invention utilizes the selective permeation characteristics of aging bags to allow yak meat to undergo complex biochemical evolution in a controlled interface environment, driven by the circulating airflow of a refrigerated refrigerator. The combination of static drainage and vacuum sealing pre-emptively removes free moisture from the surface of the meat sample and eliminates residual air within the packaging, which is crucial for inhibiting the initial proliferation of aerobic bacteria. The presence of a support frame eliminates ventilation dead zones caused by traditional placement methods, and, combined with regular turning, ensures that the mass transfer efficiency is more uniform across the surface of the meat sample.

[0008] The core logic of this processing method lies in utilizing the water vapor partial pressure difference between the inside and outside of the aging bag to induce the internal moisture of the meat sample to migrate outward in the form of water vapor. As moisture is lost, the surface muscle fibers of the meat sample undergo physical contraction and transform into a high-density, dry, hard shell. This hard shell, together with a semi-permeable membrane, forms a physical barrier that effectively prevents external microorganisms from penetrating deeper into the meat sample, while allowing metabolic gases generated internally to escape. Under a low-temperature environment lasting 10 to 21 days, deep proteolytic reactions occur inside the meat sample. Calcium-activated enzymes and cathepsins are released due to changes in cell membrane permeability, beginning to directionally degrade the skeletal proteins in myofibrils, causing the originally tight muscle structure to break down and significantly reducing the shear force of the meat sample. Along with the conversion of proteins into peptides and free amino acids, the tenderness of yak meat is improved, and flavor compounds accumulate significantly. Furthermore, the weak oxygen permeability of the aging bag allows for a moderate oxidation reaction of deep fats, and the resulting volatile compounds impart a unique aged aroma to the meat sample.

[0009] Regarding the setting of specific process parameters, this invention ensures the stability of the maturation process through multi-dimensional constraints: The selected polymer semi-permeable membrane curing bag has a water vapor permeability of 150 g / (m²). 2 ·24h) to 250g / (m 2Between 24 hours and 24 hours, this range ensures a dynamic match between the external dehydration rate and the internal moisture diffusion rate of the meat sample. If the permeability is too high, the surface of the meat sample will form a crust too quickly, preventing internal moisture from escaping; if the permeability is too low, the meat sample will remain in a state of high water activity for a long time, increasing the risk of spoilage.

[0010] During vacuum sealing, the vacuum pressure is set between -0.05MPa and -0.08MPa. The purpose is to achieve seamless negative pressure adhesion between the membrane and the meat surface. By completely eliminating air pockets at the interface, it prevents the oxidation and rancidity of fats or the local growth of microorganisms caused by local anaerobic environments.

[0011] The environmental parameters for the low-temperature aging stage were limited to a temperature of 3℃-5℃, a relative humidity of 60%-70%, and an air velocity of 0.4m / s-0.6m / s. This environmental combination simulates the kinetic conditions of an industrial aging chamber. In particular, the air velocity of about 0.5m / s can effectively maintain the water migration flux at the meat sample interface, allowing water loss and internal flavor development to proceed simultaneously.

[0012] Given the limitations of the microenvironment inside a home refrigerator, turning the meat over every 2-4 days has proven necessary. This process breaks up the ventilation obstruction caused by contact pressure on the support surface, ensuring uniform dehydration of the entire yak meat during the aging process and preventing the formation of slime or odors due to excessive local humidity.

[0013] The maturation period is controlled within 10-21 days because the tenderizing effect of yak meat is most obvious during this stage, and indicators such as amino acid nitrogen are in a period of rapid increase. If the maturation period is exceeded, the yield of finished products may drop significantly due to excessive dehydration.

[0014] The trimming thickness is set at 1.0cm-2.0cm to precisely remove the deteriorated surface layer caused by air drying and oxidation, exposing the tender and flavorful core meat inside. The remaining trimmed meat is frozen at -15℃ to -22℃ to stop the activity of endogenous proteases, thereby locking in the already formed maturation quality.

[0015] This invention provides a method for processing dry-aged yak meat for home use. It has the following beneficial effects: 1. This invention combines static drainage with vacuum sealing using a polymer semi-permeable membrane. When processed using a household air-cooled refrigerator, this invention can effectively shield against the intrusion of environmental bacteria. Because the surface free liquid is removed in advance and the residual air inside the packaging is eliminated, combined with the selective permeability of the semi-permeable membrane, the surface of the meat sample can be quickly dehydrated to form a physiologically dry hard shell. Thus, without the need for a professional aseptic aging room, the risk of spoilage during long-term storage of meat samples is significantly reduced, ensuring the safety of home cooking.

[0016] 2. The elevated design of the support frame and the periodic flipping operation in this invention solve the problem of ventilation obstruction caused by traditional placement methods from a physical perspective. This ensures that the entire surface of the yak meat can exchange heat and mass with the circulating airflow in the refrigerator. This method eliminates the humidity dead zone between the bottom of the meat sample and the contact surface, avoids the mucus or odor caused by local moisture accumulation, and ensures the uniformity of the hard shell layer formation, thereby improving the sensory quality of the finished product and the success rate of processing.

[0017] 3. This invention achieves a balance between the dehydration rate and the biochemical reaction rate of endogenous enzymes within the meat sample by limiting the permeability of the semi-permeable membrane and the maturation environment parameters. During the controlled low-temperature maturation period, the muscle fibers of yak meat undergo moderate degradation under the action of proteases, which not only significantly reduces the shear force of the meat, making it more tender, but also promotes the transformation of yak odor substances and the accumulation of flavor amino acids, giving the finished product a unique and rich aroma. Furthermore, the modified packaging method is suitable for the freezing conditions of home refrigerators, facilitating long-term storage. Attached Figure Description

[0018] Figure 1 This is a comparison chart of the hardness of various groups of samples in this invention; Figure 2 This is a comparison diagram of the chewability of various groups of samples in this invention; Figure 3 Radar chart showing the sensory evaluation of the processing technology of this invention and yak meat from different treatment groups; Figure 4 This is a comparison chart of the losses and yields during the maturation process of the present invention and each control group. Figure 5 This is a dynamic trend diagram showing the increase and decrease of the total number of microbial colonies in yak meat from different treatment groups during the aging process according to the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Examples 1-5: Example 1: This example provides a method for processing dry-aged yak meat for home use, including the following steps: (1) Select 5kg of fresh yak tenderloin, place it upside down in the original packaging at 0℃-4℃, and let it drain statically until there is no obvious liquid flowing out of the surface of the meat sample; (2) Operators shall wear disposable gloves and pack the drained yak tenderloin whole into a semi-permeable membrane aging bag. During the bagging process, direct contact between hands and the meat surface is strictly prohibited. The water vapor permeability of the semi-permeable membrane aging bag is 200 g / (m²). 2 ·24h); (3) A small household vacuum machine was used to vacuum seal the bagged meat sample. The vacuum pressure was set to -0.06MPa so that the ripening bag was tightly attached to the surface of the meat sample. (4) Place the sealed meat sample on a support rack inside the air-cooled refrigerator, ensuring ventilation from top to bottom and all sides; set the refrigerator parameters as follows: Temperature 4℃, relative humidity 65%, air velocity 0.5m / s; (5) The maturation period is 14 days, during which manual turning is carried out every 3 days to ensure uniform ventilation; (6) After aging, take out the meat sample, remove the aging bag, and use a knife to cut off the hard shell that has dried and turned black on the surface. The thickness of the cut shell is 1.5cm. Then cut the aging meat inside into slices with a thickness of 2.5cm along the vertical direction of the muscle fibers. This gives you household dry-aged yak meat. The leftover meat that is not to be eaten immediately is vacuum sealed and frozen at -18℃.

[0021] Example 2: This example provides a method for processing dry-aged yak meat for home use, including the following steps: (1) Select 4.5 kg of fresh yak tenderloin, and place it upside down in the original packaging at 0℃-4℃ to drain the surface blood. (2) Under aseptic conditions, the meat sample was placed into a semi-permeable membrane aging bag. The water vapor permeability of the semi-permeable membrane aging bag was 150 g / (m²). 2 ·24h); (3) Use a household vacuum sealer to perform vacuum sealing, with a vacuum pressure of -0.05MPa; (4) Place the meat sample on the support rack of the air-cooled refrigerator and adjust the environmental parameters as follows: Temperature 3℃, relative humidity 60%, air velocity 0.4m / s; (5) Continue to ripen for 14 days, turning the leaves over every 2 days; (6) After aging, remove the bag, cut off 1.0cm of the hard outer shell, and then cut into meat slices with a thickness of 2.2cm. Store the remaining meat frozen at -15℃.

[0022] Example 3: This example provides a method for processing dry-aged yak meat for home use, including the following steps: (1) Select 5.5 kg of fresh yak tenderloin, and invert it to drain the surface blood and tissue fluid; (2) Non-contact loading into a semi-permeable membrane curing bag, the water vapor permeability of the semi-permeable membrane curing bag is 250 g / (m 2·24h); (3) Vacuum sealing, with vacuum pressure controlled at -0.08MPa; (4) Place it on the support frame of the air-cooled refrigerator and adjust the environmental parameters as follows: Temperature 5℃, relative humidity 70%, air velocity 0.6m / s; (5) Continue to mature for 14 days, turning the leaves over every 4 days; (6) After aging, remove the bag, cut off 2.0cm of the hard outer shell, and then cut into slices with a thickness of 2.8cm. Store the remaining meat at -22℃.

[0023] Example 4: This example provides a method for processing dry-aged yak meat for home use, including the following steps: (1) Select 5 kg of fresh yak tenderloin and drain it according to the method in Example 1; (2) Pack the semi-permeable membrane curing bag into the bag without contact and then vacuum seal it; (3) Place the meat sample on the support rack of the air-cooled refrigerator and set the environmental parameters as follows: Temperature 4℃, relative humidity 65%, air velocity 0.5m / s; (4) The maturation period is shortened to 10 days, during which the leaves are turned over every 3 days; (5) After aging, remove the bag, cut off 1.2cm of the hard outer shell, and then cut into slices with a thickness of 2.5cm.

[0024] Example 5: This example provides a method for processing dry-aged yak meat for home use, including the following steps: (1) Select 5 kg of fresh yak tenderloin and drain it according to the method in Example 1; (2) Pack the semi-permeable membrane curing bag into the bag without contact and then vacuum seal it; (3) Place the meat sample on the support rack of the air-cooled refrigerator and set the environmental parameters as follows: Temperature 4℃, relative humidity 65%, air velocity 0.5m / s; (4) The maturation period is extended to 21 days, during which the leaves are turned over every 3 days; (5) After aging, remove the bag. Due to the extended aging time, the dried shell becomes thicker. Cut off 1.8cm of the hard shell on the surface and then cut it into meat slices with a thickness of 2.5cm.

[0025] Comparative Examples 1-5: Comparative Example 1: The difference compared to Example 1 is as follows: Fresh yak tenderloin was used and cooked directly without any dry aging process.

[0026] Comparative Example 2: The difference compared to Example 1 is as follows: In step (2), a regular airtight vacuum bag is used instead of a semi-permeable membrane curing bag, and the other steps and environmental parameters are the same.

[0027] Comparative Example 3: The difference compared to Example 1 is as follows: In step (2), no packaging bags are used. The yak tenderloin is placed directly on the refrigerator support rack for aging, and the other parameters are the same.

[0028] Comparative Example 4: The difference compared to Example 1 is as follows: In step (4), no support frame is used. The packaged meat sample is placed directly flat on the refrigerator shelf without being turned over.

[0029] Comparative Example 5: The difference compared to Example 1 is as follows: In step (3), the meat sample is simply put into a semi-permeable membrane bag and sealed without vacuuming, so that air is left inside the bag and the membrane does not stick tightly to the surface of the meat.

[0030] Test Examples 1-4: Test Example 1: Comparative Experiment of Texture Properties Analysis Sample pretreatment: Yak tenderloin meat after aging was taken from Examples 1-5 and Comparative Examples 1-4, and pan-fried under the aforementioned cooking conditions. After the meat samples cooled naturally to room temperature, they were cut into strips measuring 5cm x 3cm x 1.2cm parallel to the muscle fiber direction. Three parallel samples were prepared for each group to ensure the flatness of the test surface and avoid the formation of a crust due to uneven heating, which could affect the accuracy of the measurement.

[0031] Instrument parameter settings: A TA-XT plus texture analyzer was used, with a P / 36R cylindrical probe selected. The measurement mode was set to the double compression mode for texture property analysis. Specific parameter configurations are as follows: The initial velocity was 2 mm / s, the test velocity was 1 mm / s, and the post-test velocity was 1 mm / s. The trigger force was set to 20 g, the time interval between two compressions was 5 seconds, and the target compression ratio was set to 75%.

[0032] Measurement Procedure: Place the sample to be tested in the center of the texture analyzer base and start the test program. The probe compresses the meat sample vertically downwards, simulating the human chewing process. Record the relationship curve between probe displacement and force value. By analyzing the mechanical curves of the first and second cycles, extract two core evaluation indicators: hardness and chewiness. Hardness is taken as the peak force during the first compression cycle, while chewiness is calculated as the product of hardness, cohesiveness, and elasticity.

[0033] Table 1. Results of determination of texture parameters of yak meat in different treatment groups

[0034] Based on the data in Table 1, and in conjunction with the appendix... Figure 1 and attached Figure 2 It can be observed that the yak meat in each embodiment processed by the processing technology of the present invention shows a decreasing trend in terms of hardness and chewiness.

[0035] Combine Table 1 and Appendix Figure 1 (Hardness Comparison Chart) Analysis shows that the fresh yak meat in Comparative Example 1 had the highest hardness, exceeding 26,000g, exhibiting significant toughness and poor cutting feel. In contrast, the hardness of Example 1 decreased most drastically, stabilizing at around 14,218g, a reduction of nearly 45%. This change in macroscopic mechanical parameters confirms the effectiveness of the endogenous enzymatic tenderizing mechanism. Under a constant temperature of 4℃, the semi-permeable membrane aging bag maintained a suitable water activity inside the meat, enabling calcium-activated enzymes to specifically degrade the Z-disc structure and skeletal proteins in myofibril proteins. Since the Z-disc is a core node maintaining the physical integrity of the sarcomere, its weakening leads to a loosening of the muscle's spatial structure, thus macroscopically manifesting as a reduction in compressive resistance.

[0036] Combine Table 1 and Appendix Figure 2 (Comparison of chewability) Analysis shows that chewability reflects the energy required for meat samples to break down in the oral cavity and reach a swallowable state. Comparative Examples 1 and 2 (using ordinary vacuum bags) showed significantly higher chewability than the Example group. Comparative Example 2, due to the use of an airtight ordinary packaging bag, prevented the directional migration of moisture, leading to inhibition of endogenous enzyme activity by the accumulation of metabolic byproducts, and lacking the fiber structure remodeling resulting from controlled moisture loss. In contrast, Examples 1-5 utilized a semi-permeable membrane to allow moisture to diffuse outward in the form of vapor. This physical contraction, combined with the biochemical cleavage by endogenous enzymes, made muscle fibers easier to separate while breaking down.

[0037] Data comparison shows that Example 1, as the optimal parameter group, outperforms the other examples in all aspects. Examples 2 and 3, deviating from the optimal temperature range, experienced slight fluctuations in the enzymatic reaction rate, resulting in less tenderizing effects than Example 1. Comparative Example 4, lacking mechanical ventilation support and manual turning, suffered from uneven heat transfer due to stagnant airflow in some areas, partially offsetting the texture improvement effect of ripening.

[0038] In summary, this invention successfully triggered the evolution of the deep biochemical structure inside yak meat by regulating the osmotic pressure of a polymer semi-permeable membrane and achieving a kinetic balance with the air-cooled environment. Test data not only demonstrates the definitive advantage of this method in improving the "toughness" of yak meat, but also verifies the necessity of characteristics such as temperature, humidity, wind speed, and support operation for achieving unexpected tenderizing effects.

[0039] Test Example 2: Sensory Evaluation and Flavor Quality Analysis Evaluation Personnel Selection and Training: An evaluation team of 10 professionals with experience in food sensory evaluation was formed. Prior to the formal experiments, specialized training was provided on the unique gamey (fishy) odor of yak meat, the nutty / cheesy aroma produced by dry aging (aged flavor), juiciness, and overall acceptability. Standard samples at different aging levels were provided to standardize evaluation criteria, ensuring that evaluators could accurately identify and quantify various sensory indicators.

[0040] Sample Cooking Process: Take the trimmed meat slices from Examples 1-5 and Comparative Examples 1, 2, and 5. Use a constant-temperature pan-frying method, preheating the pan to 180°C without adding any seasonings. Fry each side for 2 minutes, ensuring the center temperature of the meat sample reaches approximately 72°C (medium-rare). After frying, cut the meat sample into 1.5cm x 1.5cm x 1.5cm cubes, place them on randomly numbered white ceramic plates, and keep them warm in a 60°C constant-temperature incubator to minimize aroma loss.

[0041] Sensory evaluation was conducted in a standard sensory evaluation laboratory. A 9-point scoring system was used (1 point represents very weak, and 9 points represent very strong). Each evaluator conducted blind tests on the samples in an independent cubicle, assessing the intensity of the gamey odor, the concentration of aged flavor, juiciness, and overall acceptability. Between samples, evaluators were required to rinse their mouths with warm water and soda crackers to eliminate any residual flavor interference.

[0042] Results Recording and Statistics: Raw data of ratings from 10 evaluators were collected, outliers with deviations from the mean exceeding 2 standard deviations were removed, and the arithmetic mean of the remaining valid ratings was taken as the final sensory score.

[0043] Table 2. Statistical table of sensory index evaluation of yak meat from different treatment groups

[0044] Based on the data in Table 2, and in conjunction with the appendix... Figure 3 As can be observed from the sensory evaluation radar chart shown, the processing technology of the present invention has a significant effect on improving the flavor characteristics of yak meat and enhancing its overall acceptability.

[0045] Combined with appendix Figure 3Neutron plot (a) analyzes the differences between Example 1 and Comparative Example 1 (fresh meat), showing a clear "axial reversal" characteristic in the graphic distribution. The evaluation trajectory of Comparative Example 1 is extremely biased towards the "yak muttony" axis, with a score as high as 8.42, while its projection area on the "aged flavor" and "overall acceptability" axes is extremely small. After being processed by this process, the center of gravity of the graphic of Example 1 shifts significantly, the muttony index is greatly reduced to 1.84, and the aged flavor index expands significantly to 8.56 on the periphery. This reshaping of the sensory trajectory verifies the effectiveness of the synergistic mechanism of physical dehumidification and biochemical transformation. During the 14-day dynamic aging period, the osmotic pressure gradient formed by the air-cooled circulation system and the semi-permeable membrane accelerates the controlled loss of moisture and crusting of the meat surface. The distinctive odor of yak meat mainly originates from branched-chain fatty acids in the tissue. Through the low-temperature and low-humidity interface constructed by this process, some volatile odor substances migrate and are expelled with moisture, while others are transformed by endogenous enzymes with precursor substances produced by protein degradation, thus achieving effective control of the original odor.

[0046] Combined with appendix Figure 3 Neutron plot (b) analyzes the advantages and disadvantages of this scheme compared to other processing techniques. Comparing Example 1 and Comparative Example 2 (wet aging), it is evident that while Comparative Example 2 shows some performance in "juiciness," it significantly collapses in the "aged flavor" dimension. This is because ordinary airtight vacuum bags block the moisture migration path, leading to the accumulation of metabolic byproducts within the tissue and dilution of flavor substances. Example 1, however, utilizes the selective permeability of a polymer semi-permeable membrane to allow moisture to escape in the form of vapor, achieving physical concentration of volatile aroma components. Furthermore, the graphic envelope area of ​​Example 1 in "overall acceptability" is much larger than that of Comparative Example 5 (non-vacuum packaging), demonstrating the protective effect of the vacuum negative pressure environment on sensory quality. The non-vacuum state results in residual air inside the bag, inducing oxidative rancidity of the fatty tissue, manifested in the radar plot as a decrease in the purity of the aged flavor and a rebound in the off-flavor score.

[0047] Regarding the succulence index, although dry aging involves a reduction in total moisture content, the score of Example 1 (7.12) was still significantly better than that of Comparative Example 1 (4.35). (See attached...) Figure 3 As can be seen from the axial proportions, this invention achieves flavor concentration without sacrificing juiciness. This is because the balance between mechanical ventilation and heat exchange ensures a moderate thickness of the surface dry crust (1.0-2.0 cm), which acts as a physical barrier, effectively reducing the water-holding capacity loss of deeper tissues. Simultaneously, the conversion of proteins into peptides and amino acids under enzymatic reactions enhances the hydrophilicity of muscle tissue at the microscopic level.

[0048] In summary, the quantitative scores in Table 2 and the attached... Figure 3The graphical representations collectively confirm the advanced nature of the present invention. By precisely adjusting temperature, humidity, and aerodynamic parameters, this process not only successfully eliminates the inherent unpleasant odor of yak meat but also induces a highly distinctive aged aroma spectrum, thus demonstrating the causal logic between the technical features and beneficial effects of the present invention from a sensory perspective.

[0049] Test Example 3: Determination of Processing Loss and Yield Initial mass determination: Before the meat samples of each example and comparative example were bagged and sealed, the mass of the original meat samples was determined using an electronic balance with a sensitivity of 0.1g, and recorded as follows. During the measurement process, it is necessary to ensure that the surface of the meat sample is completely drained to avoid interference from surface moisture on the original readings.

[0050] Post-aging quality determination: After the specified aging period, the meat sample is removed from the refrigerator support shelf, the aging bag is removed, and its overall weight is immediately measured and recorded. The mass loss at this point mainly stems from the controlled evaporation of water through the semipermeable membrane.

[0051] Post-trimming quality determination: Following the trimming thickness specified in each embodiment, a professional slitting tool was used to remove the hard outer layer (including the oxidized discoloration layer and the dehydrated hardened layer) from the surface of the meat sample until the inner, reddish-brown, soft, aged meat core was exposed. The weight of the trimmed edible meat was measured and recorded. .

[0052] Indicator Calculation: Based on the measured raw data, calculate the following three key indicators.

[0053] Maturation dry loss rate ; Trimming loss rate ; Final yield .

[0054] Table 3. Statistical table of processing loss and yield of yak meat in different treatment groups

[0055] Based on the data in Table 3, and in conjunction with the appendix... Figure 4 As can be seen from the processing quality composition distribution diagram shown, the semi-permeable membrane curing process used in this invention exhibits excellent finished product yield control while maintaining the quality characteristics of dry curing.

[0056] Combined with appendix Figure 4 Subfigure (a) analysis of absolute mass composition shows that the original meat samples in each group ( The weight remained around 5kg for all samples, but the weight distribution structure after maturation differed significantly. The black blocks at the bottom of the diagram represent the final product weight. The dark gray blocks in the middle represent trimming loss, while the light gray blocks at the top represent aging loss. The final product weight of Example 1 reached 3.65 kg, with its black blocks occupying the majority of the column's space. In contrast, the column of Comparative Example 3 (naked aging) showed significant "shrinkage," with the lowest black block height at only 2.62 kg. This clearly demonstrates that in the absence of a semi-permeable membrane physical barrier, the internal moisture of yak meat is directly exposed to the air-cooled circulating environment, escaping dramatically due to the humidity gradient, resulting in substantial dehydration and shrinkage of the meat sample.

[0057] Combined with appendix Figure 4 Analysis of the proportions in subfigure (b) shows that the aging dryness loss rate of Example 1 was controlled at approximately 14.14%, a value represented by the proportion of the top layer color block in the figure. This result confirms the selective permeation mechanism of the semi-permeable membrane, namely, that the micropores in the membrane structure provide effective physical resistance to water vapor migration. This controlled dynamic balance ensures both the appropriate dehydration required for flavor concentration and avoids irreversible texture loss in the meat sample due to excessive drying.

[0058] Regarding pruning losses, observe Figure 4 In subfigure (b), the proportion of dark gray patches in the middle layer is significantly lower in Example 1 (15.31%) than in Comparative Example 3 (30.13%). Mechanistic analysis indicates that the negative pressure adhesion between the semi-permeable membrane and the meat sample surface alters the surface oxygen partial pressure. Combined with a controlled water migration rate, this induces the formation of a dense and uniformly thick hard shell. This hard shell layer, acting as a physical sacrificial layer, effectively locks in the color and elasticity of the internal meat. In Comparative Example 3, due to excessively rapid and uneven surface water loss, the oxidative discoloration layer penetrates deeper into the core, reflected in the figure as a sharp expansion of the proportion of dark gray patches, forcing a substantial increase in trimming.

[0059] The yield data further highlights the economic feasibility of this approach. The final yield of Example 1 (bottom color block in sub-figure (b) of the attached figure) remained at 72.71%, while that of Comparative Example 3 was only 51.57%. Although Comparative Example 2 (ordinary vacuum bag) had the highest yield (97.85%), with the pillar almost entirely covered in black, it can be seen from Test Example 2 that it is essentially a wet-curing process due to the lack of a moisture migration path, and therefore cannot achieve the sensory gains unique to dry curing.

[0060] Furthermore, the data fluctuations in Examples 2 to 5 are as follows: Figure 4This is also clearly reflected in the data. In Example 5, due to the extended curing time of 21 days, the two gray patches above the pillars thickened significantly, resulting in a final yield rate of 62.97%. This indicates that a curing cycle of approximately 14 days achieves a better balance between quality improvement and economic losses. In Example 3, due to the higher ambient temperature and humidity, although the moisture migration path was shortened, the proportion of trimmed patches increased to 19.70%, which is directly related to the increased surface oxidation and thickening of the discoloration layer under high temperature conditions.

[0061] In summary, the measurement results in Table 3 are consistent with those in the appendix. Figure 4 The graphical representations together quantitatively verified the role of the innovative mechanism of this invention in improving processing efficiency. By precisely matching the semi-permeable membrane parameters with the air-cooling dynamic environment, this scheme successfully overcomes the technical barrier of excessive losses in traditional dry aging. While ensuring the evolution of yak meat flavor and tenderization effect, it significantly improves the return on edible meat, providing economic evidence to support the application of this process in a home environment.

[0062] Test Example 4: Microbial Safety Testing Sampling and Preparation: Meat samples from Examples 1, 2, 3, and 4 were aseptically sampled on days 0, 7, 14, and 21 of the maturation period. Using a sterile scalpel, three different sites were randomly selected on the surface of the meat sample, and surface tissue with a thickness of approximately 0.5 cm and a total weight of 25 g was obtained. The samples were placed in a sterile homogenizing bag containing 225 mL of sterile physiological saline and homogenized using a beater for 2 minutes to prepare a 1:10 sample stock solution.

[0063] Serial dilution and inoculation: Add 1 mL of the stock solution to 9 mL of sterile physiological saline, and perform serial dilutions 10-fold. Based on the expected bacterial load, select 2-3 consecutive suitable dilutions, and inoculate 1 mL of each dilution into Petri dish counting agar medium. Prepare 3 replicates for each dilution, and simultaneously prepare a blank control to monitor the sterility of the environment and reagents.

[0064] Culture and Counting: The inoculated culture medium was placed in a 30℃ incubator for 48 h ± 2 h. Plates with colony counts between 30-300 CFU were selected for counting. The total colony count for each group at different time points was recorded, and the arithmetic mean was calculated. Experimental results are presented in logarithmic form (log...). 10 (CFU / g) indicates the growth and decline trends of microorganisms during the maturation process.

[0065] Table 4. Dynamic changes in total bacterial count during aging of yak meat in different treatment groups.

[0066] Based on the data in Table 4, and in conjunction with the appendix... Figure 5 The dynamic change curve of total microbial colony count shown demonstrates that the processing technology of this invention has significant advantages in inhibiting microbial proliferation during the maturation process of yak meat and ensuring product safety.

[0067] Combined with appendix Figure 5 Subplot (a) analysis of the overall group trend shows that the initial total colony count (day 0) in each group is distributed within 3.4 log₂. 10 The levels were relatively low, around CFU / g. As the maturation period progressed, the slopes of the curves for each treatment group showed significant differentiation. The horizontal dashed line in the figure represents the safety threshold for meat spoilage (6.0 log...). 10 (CFU / g). The proliferation curve of Example 1 had the gentlest slope, and its total colony count remained below the safety limit throughout the entire 21-day experimental period, reaching only 4.31 log at the end of the process on day 14. 10 CFU / g. In contrast, the curve for Comparative Example 3 (naked ripening) crossed the safety limit around day 10, reaching 6.45 log on day 14. 10 CFU / g. This trajectory difference confirms the barrier effect of the semi-permeable membrane's physical barrier, which effectively prevents exogenous bacteria from the refrigerator environment from settling on the meat sample surface.

[0068] Combined with appendix Figure 5 Subfigure (b) focuses on analyzing the safety margins of this scheme and Comparative Example 4 (static placement). The vertical dotted lines in the figure mark the recommended end date of maturation (day 14). It can be clearly seen that at day 14, there is a significant longitudinal displacement deviation between Example 1 and Comparative Example 4. Due to the lack of ventilation assistance from the support frame and manual turning, the total colony count in Comparative Example 4 had risen to 6.12 log on day 14. 10 The concentration of CFU / g exceeded the safety limit. This phenomenon indicates that the bottom area where the meat sample contacted the refrigerator shelf experienced obstructed airflow, leading to reduced local heat exchange efficiency and increased humidity. This disrupted the formation of the protective hard shell layer, creating a microenvironment conducive to the growth of psychrophilic putrefactive bacteria. Example 1, through three-dimensional ventilation achieved by mechanical support and regular turning, ensured a uniform decrease in water activity across the entire surface of the meat sample, achieving overall inhibition of microbial growth through physical means.

[0069] Furthermore, comparing the curves of Example 1 and Comparative Example 2 (ordinary vacuum bag), it can be seen that the proliferation rate of Comparative Example 2 was significantly accelerated in the later stage of maturation (14-21 days), reaching nearly 7.0 log on by day 21. 10CFU / g. This is attributed to the fact that ordinary non-permeable packaging bags prevent the drainage of tissue exudate, creating a high-humidity microenvironment inside the bag and inducing logarithmic growth of microorganisms. In contrast, Example 1 utilizes the selective permeability of a semi-permeable membrane to allow water to escape as vapor, maintaining a dry layer with low water activity on the meat surface, thereby chemically restricting the metabolic activity of microorganisms.

[0070] In summary, the experimental data in Table 4 and the appendix Figure 5 The graphic trajectories together confirm the supporting role of the technical features of this invention in ensuring food safety. Through the physical shielding of the polymer semi-permeable membrane, the low water activity interface formed by controlled dehydration, and the environmental dynamic balance maintained by mechanical support and turning operations, this solution successfully controls the microbial risk of yak jerky aging within a safe threshold.

Claims

1. A method for processing dry-aged yak meat for home use, characterized in that, Includes the following steps: Fresh yak meat is subjected to static drainage treatment until no obvious liquid flows out from the surface of the meat sample. After draining, the yak meat is placed into aging bags and vacuum-sealed to make the aging bags adhere to the surface of the meat sample under negative pressure. The packaged meat sample was placed in an air-cooled refrigerator and supported by a support frame so that the sides and bottom of the meat sample were in contact with the airflow for low-temperature maturation. During the aging process, the meat samples are turned over periodically to ensure that the surface of the meat samples is in uniform contact with the air-cooled airflow. After aging, the aging bag is removed, and the hardened outer layer of the meat sample that has dried and changed color is cut off to obtain the home-cooked dry-aged yak meat.

2. The processing method for household dry-aged yak meat according to claim 1, characterized in that, The curing bag is a polymer semi-permeable membrane curing bag.

3. The processing method for household dry-aged yak meat according to claim 2, characterized in that, The water vapor permeability of the polymer semi-permeable membrane curing bag is 150 g / (m²). 2 ·24h) to 250g / (m 2 •24h).

4. The processing method for household dry-aged yak meat according to claim 1, characterized in that, The vacuum pressure for the vacuum sealing process is set to -0.05MPa to -0.08MPa.

5. A method for processing household dry-aged yak meat according to claim 1, characterized in that, The environmental parameters for the low-temperature maturation are set as follows: The temperature is 3℃-5℃, the relative humidity is 60%-70%, and the air velocity is 0.4m / s-0.6m / s.

6. A method for processing household dry-aged yak meat according to claim 5, characterized in that, The environmental parameters are set as follows: The temperature is 4℃, the relative humidity is 65%, and the air velocity is 0.5m / s.

7. A method for processing household dry-aged yak meat according to claim 1, characterized in that, The low-temperature maturation period is 10-21 days.

8. A method for processing household dry-aged yak meat according to claim 1, characterized in that, The meat samples are to be turned over every 2-4 days.

9. A method for processing household dry-aged yak meat according to claim 1, characterized in that, The thickness of the hard shell layer removed is 1.0cm-2.0cm.

10. A method for processing household dry-aged yak meat according to claim 1, characterized in that, After removing the hard outer layer, the meat sample is cut into slices along the direction perpendicular to the muscle fibers; the remaining material after cutting is repackaged and frozen at -15℃ to -22℃.

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