Salted egg yolk sausage and preparation method thereof

Abstract

The invention belongs to the technical field of meat product processing, and discloses a salted egg yolk sausage and a preparation method thereof. The salted egg yolk sausage comprises the following raw materials: sausage meat and salted egg yolk particles, wherein the surface layer of the salted egg yolk particle is provided with a reinforced surface layer formed by low-temperature and low-humidity treatment, and the surface of the particle is coated with a gel protective film formed by crosslinking sodium alginate and calcium ions. The salted egg yolk particles are subjected to low-temperature and low-humidity pretreatment, a compact reinforced surface layer is formed on the surface layer of the salted egg yolk particles, and the mechanical strength is remarkably improved. And the gel protection film coating the salted egg yolk particles has a three-dimensional network structure, so that the structure can be kept stable in the whole drying process, and the physical barrier effect is excellent. The film can effectively prevent the salted egg yolk from being broken under the mechanical action of follow-up mixing and filling, meanwhile, premature seeping of grease is continuously blocked in the whole drying stage, the greasy feeling of the product is remarkably reduced, and the integrity of salted egg yolk particles and the clear presentation of the flavor are ensured.

Description

Technical Field

[0001] This invention relates to the field of meat processing technology, specifically to a salted egg yolk sausage and its preparation method. Background Technology

[0002] Chinese sausage is a traditional Chinese meat product, known for its unique flavor and long shelf life, making it a favorite among consumers. To enrich the product portfolio and enhance perceived value, the industry has successively developed specialty sausages with various added ingredients. Among these, adding salted egg yolk granules to create "Golden Sand Sausage" or "Salted Egg Yolk Sausage" has become a popular innovation in recent years.

[0003] However, in current production practices, directly mixing salted egg yolk granules into sausage filling and traditionally drying them faces a series of long-standing technical challenges: First, the soft texture of salted egg yolk granules makes them prone to breakage and deformation during subsequent mechanical processing such as mixing and filling, resulting in a lack of a complete "granular texture" in the product, affecting both appearance and taste. Second, salted egg yolks are rich in oil, which has a low melting temperature. During the traditional sausage drying process (usually 45-55℃), the oil from the salted egg yolks melts and seeps into the meat filling in the early stages, not only causing the product surface to become oily and greasy, but also causing the salted egg yolk flavor to mix prematurely with the sausage flavor, resulting in a blurred and indistinct flavor profile and a loss of the expected flavor layers. Furthermore, salted egg yolk granules and sausage filling are systems with vastly different water activities and textures; the uncoordinated moisture migration during drying can affect the overall uniformity and stability of the product's texture.

[0004] Existing improvement solutions mostly focus on adjusting process parameters or adding stabilizers, but these are all passive adjustments and cannot fundamentally solve the inherent thermodynamic contradictions between salted egg yolk particles and sausage base. Therefore, there is an urgent need for an innovative system solution to simultaneously achieve physical protection of salted egg yolk particles, precise control of oil release, and layered flavor presentation.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The present invention aims to solve at least one of the above technical problems, and provides a salted egg yolk sausage with intact salted egg yolk particles, clear flavor layers, and stable quality, as well as a method for preparing the same.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: On one hand, the present invention provides a salted egg yolk sausage, the raw materials of which include sausage meat and salted egg yolk particles; wherein, the surface of the salted egg yolk particles has a reinforced surface layer formed by low temperature and low humidity treatment, and the surface of the particles is coated with a gel protective film formed by cross-linking of sodium alginate and calcium ions.

[0008] Preferably, the thickness of the gel protective film is 20-60 μm.

[0009] Preferably, the amount of salted egg yolk particles added accounts for 8%-12% of the total weight of the sausage filling.

[0010] On the other hand, the present invention provides a method for preparing the above-mentioned salted egg yolk sausage, comprising the following steps: pre-treating the surface of the salted egg yolk particles to form a reinforced surface layer with higher mechanical strength than the inner core; The surface of the pretreated salted egg yolk particles is coated with a gel protective film formed by cross-linking sodium alginate and calcium ions to obtain the treated salted egg yolk particles. Mix the processed salted egg yolk granules with the sausage filling and stuff the mixture into sausage casings; The sausages are dried after being filled.

[0011] Preferably, the surface pretreatment method is as follows: place the salted egg yolk particles in an environment with a temperature of 2-5℃ and a relative humidity of 25%-35% for 15-30 minutes to reduce the surface water activity to below 0.65.

[0012] Preferably, the coating method of the gel protective film is as follows: the surface-pretreated salted egg yolk particles are immersed in a sodium alginate solution with a concentration of 1.0%-1.5% for 30-60 seconds and then filtered; subsequently, they are immersed in a calcium chloride solution with a concentration of 2.0%-3.0% for cross-linking and curing for 20-40 seconds; after removal, they are quickly rinsed with clean water and drained to form a gel protective film on the surface of the particles.

[0013] Preferably, the immersion temperature of the sodium alginate solution is 40-50°C.

[0014] Preferably, the cross-linking and curing temperature of the calcium chloride solution is room temperature (20-25℃).

[0015] Preferably, the drying process is as follows: Rapid setting stage: temperature 55-60℃, time 1.5-2.5h; Dehydration and maturation stage: temperature 50-55℃, time 40-50h; Stable drying stage: temperature 45-48℃, time 20-25h.

[0016] More preferably, the temperature of the dehydration and maturation stage is set to 52-54°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a low-temperature, low-humidity pretreatment process to form a dense, reinforced surface layer on the salted egg yolk, followed by coating with a high-mechanical-strength sodium alginate-calcium ion gel membrane, providing dual physical protection for the salted egg yolk particles. This allows the particles to effectively withstand the mechanical shearing forces of subsequent mixing and filling, maintaining a salted egg yolk particle integrity rate of over 98% in the final product, resulting in a visually appealing "golden sandwich" effect.

[0018] Unlike traditional melting point-triggered coatings, the gel protective film used in this invention maintains its three-dimensional network solid structure throughout the entire sausage drying temperature range (45-75℃) without undergoing a phase change. This stable physical barrier effectively locks in the oil inside the salted egg yolk from start to finish, preventing it from prematurely and excessively seeping into the meat filling during the early and middle stages of drying, thereby significantly reducing the surface gloss and greasy feeling in the mouth of the final product.

[0019] This invention boasts excellent process compatibility and preserves the natural flavor: both sodium alginate and calcium chloride are food-grade additives, ensuring safety and harmlessness. The film-forming process is gentle, avoiding high-temperature melting, thus maximizing the preservation of the authentic flavor of the salted egg yolk. The resulting gel film is transparent and odorless, introducing no additional off-flavors and ensuring a pure and natural fusion of the sausage and salted egg yolk flavors. Furthermore, this process eliminates the need for complex drying procedures that precisely match the coating's melting point, making it more adaptable to existing sausage drying processes. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] The first embodiment of the present invention provides a salted egg yolk sausage, the raw materials of which include sausage meat and salted egg yolk particles; wherein, the surface of the salted egg yolk particles has a reinforced surface layer formed by low temperature and low humidity treatment, and the surface of the particles is coated with a gel protective film formed by cross-linking of sodium alginate and calcium ions.

[0022] The reinforced surface layer is formed by briefly surface-treating salted egg yolk particles in a low-temperature, low-humidity environment. Under these specific conditions, free water on the particle surface evaporates rapidly and selectively, causing the surface water activity to drop quickly to below 0.65, while the core remains relatively high. This dramatic water activity gradient, accompanied by a relative increase in surface salt and protein concentration, and the densification of the fat crystal network, together construct a dense physical barrier layer with significantly enhanced mechanical strength on the particle surface—the "reinforced surface layer."

[0023] The primary purpose of this reinforced surface is to address the industry-wide problem of salted egg yolk granules easily breaking due to mechanical forces (stirring, filling) during sausage processing. By giving the granules a robust "shell," it ensures that they maintain their intact cubic shape in all subsequent processing steps.

[0024] The gel protective film is formed in situ on the particle surface through an ionic cross-linking reaction. After the sodium alginate solution forms a uniform liquid film on the surface of the salted egg yolk particles, it comes into contact with calcium ions in the calcium chloride solution, and cross-linking occurs instantaneously, forming a strong, water-insoluble calcium alginate gel film. This film has a three-dimensional network structure, high mechanical strength, and good thermal stability, and remains intact throughout the temperature range of the entire sausage drying process. It acts like a "protective suit" for the salted egg yolk particles, effectively preventing the migration of internal oils and breakage caused by external forces.

[0025] The second embodiment of the present invention provides a method for preparing salted egg yolk sausage, comprising the following steps: S101, the surface of the salted egg yolk particles is pretreated to form a reinforced surface layer with higher mechanical strength than the inner core; S102, a gel protective film formed by cross-linking sodium alginate and calcium ions is coated on the surface of the pretreated salted egg yolk particles to obtain the treated salted egg yolk particles. S103: Mix the processed salted egg yolk granules with the sausage filling and stuff it into the casing; S104 is used to dry the sausages after they have been filled.

[0026] Step S101 aims to improve the integrity of salted egg yolk particles during subsequent mechanical processing (stirring, filling) and to establish a preliminary physical water-locking barrier for their internal oils.

[0027] The breakage and oil seepage of salted egg yolk particles stem from insufficient surface structural strength and high water activity. This invention employs a low-temperature, low-humidity, time-controlled treatment to rapidly evaporate free water from the particle surface. This results in a sharp decrease in surface water activity (Aw), a relative increase in salt and protein concentration, and a denser fat crystal network. These three factors work together to form a "high-strength outer shell" on the surface of the salted egg yolk particles, with significantly higher mechanical strength than the inner core. This outer shell exhibits higher shear modulus and lower oil migration, while retaining the internal oily, sandy texture.

[0028] The key to this step lies in the combined effect of temperature, relative humidity, and processing time. The processing temperature is 2-5℃, below the point where the salted egg yolk oil begins to soften significantly, ensuring the processing takes place in a solid state. A relative humidity of 25%-35% drives surface moisture evaporation. The processing time is 15-30 minutes; too short a time results in insufficient shell formation, while too long a time may lead to excessive dehydration extending inwards, affecting the texture of the core. After this surface pretreatment, the water activity of the surface layer (approximately 1mm depth) of the salted egg yolk particles should drop below 0.65, while the core remains above 0.72, creating a significant gradient. The compressive strength of the particles increases by more than 50% compared to before treatment.

[0029] This step can be completed in a temperature- and humidity-controlled fluidized bed device, using salted egg yolk particles cut into approximately 10 mm³ cubes.

[0030] Step S102 is one of the core improvements of this invention, aiming to apply a physical barrier film that is effective throughout all stages. The specific method is as follows: a) Preparation and coating with sodium alginate solution: Prepare a 1.0%-1.5% sodium alginate solution using purified water at 40-50℃, stirring until completely dissolved and free of bubbles. Immerse the pretreated salted egg yolk particles in the solution for 30-60 seconds, ensuring even surface coverage.

[0031] b) Draining: Remove the egg yolk particles and drain off the excess solution for about 1-2 minutes to control the thickness of the gel protective film.

[0032] c) Calcium chloride solution solidification: Immerse the filtered egg yolk particles in a 2.0%-3.0% calcium chloride solution at room temperature and gently stir for 20-40 seconds. An opaque gel film will instantly form on the surface. Timing is crucial in this step; too short a time will result in insufficient cross-linking and weak film strength; too long a time will result in an overly thick and rigid film, potentially affecting the texture.

[0033] d) Rinsing and draining: Quickly rinse the solidified egg yolk particles with clean water for 10-15 seconds to remove residual calcium ions on the surface and avoid bitterness. After rinsing, drain the surface water thoroughly and set aside.

[0034] The gel protective film formed by this method is approximately 20-60 μm thick, uniform and dense, and provides excellent resistance to mechanical impact and oil blocking properties for salted egg yolk particles.

[0035] The drying process in step S104 has been adjusted, removing the original "release and fusion stage" because the gel protective film acts as a barrier throughout the process, eliminating the need for temperature-triggered release. The adjusted process focuses more on the dehydration and maturation of the sausage itself. Rapid setting stage (55-60℃, 1.5-2.5h): rapidly coagulates and sets the proteins on the surface of the casing.

[0036] Dehydration and maturation stage (50-55℃, preferably 52-54℃, 40-50h): This stage is the main stage for sausage dehydration, color development, and flavor formation. The gel membrane is structurally stable at this temperature and can effectively prevent the seepage of salted egg yolk oil.

[0037] Stabilization drying stage (45-48℃, 20-25h): Further equalize moisture content and stabilize product quality.

[0038] The preparation method and effects of salted egg yolk sausage are described in detail below through several specific examples.

[0039] Example 1: Preparation method of salted egg yolk sausage Salted egg yolk particles cut into 10 mm³ were placed in a fluidized bed and air at a temperature of 2°C and a relative humidity of 30% was introduced. After 25 minutes of treatment, pre-treated salted egg yolk particles were obtained. The pretreated salted egg yolk granules were immersed in a 1.2% sodium alginate solution at 50℃ for 40 seconds, then drained for 90 seconds. Subsequently, they were immersed in a 2.5% calcium chloride solution at room temperature for 30 seconds for cross-linking and curing. After removal, they were quickly rinsed with water for 12 seconds and drained, forming a uniform gel protective film (approximately 35 μm thick) on the surface.

[0040] Mix the above-treated salted egg yolk granules with regular Cantonese sausage filling at low speed for 3 minutes at a ratio of 10% of the total weight of the sausage filling, and then stuff the mixture into natural pig casings.

[0041] Drying process: First, 65℃, relative humidity RH 65%, wind speed 0.8 m / s, for 2 hours; then 52.0℃, for 48 hours, with RH decreasing from 60% to 45% in stages; finally 47℃, RH 38%, for 22 hours.

[0042] Example 2: Preparation method of salted egg yolk sausage Salted egg yolk particles cut into 10 mm³ were placed in a fluidized bed and air at a temperature of 5°C and a relative humidity of 25% was introduced and treated for 15 minutes to obtain pretreated salted egg yolk particles. The pretreated salted egg yolk granules were immersed in a 1.5% sodium alginate solution at 45℃ for 30 seconds, then drained for 60 seconds. Subsequently, they were immersed in a 3.0% calcium chloride solution at room temperature for 20 seconds for cross-linking and curing. After removal, they were quickly rinsed with water for 10 seconds and drained, resulting in a uniform gel protective film (approximately 25 μm thick) on the surface.

[0043] Mix the above-treated salted egg yolk granules with regular Cantonese sausage filling at low speed for 4 minutes at a ratio of 9% of the total weight of the sausage filling, and then stuff the mixture into natural pig casings.

[0044] Drying process: First, 65℃, relative humidity RH 60%, wind speed 0.8 m / s, for 1.5 hours; then 53.5℃, for 42 hours, with RH continuously decreasing from 60% to 45%; finally 48℃, RH 35%, for 20 hours.

[0045] Example 3: Preparation method of salted egg yolk sausage Salted egg yolk particles cut into 10 mm³ were placed in a fluidized bed and air at a temperature of 3°C and a relative humidity of 35% was introduced. After 30 minutes of treatment, pre-treated salted egg yolk particles were obtained. The pretreated salted egg yolk granules were immersed in a 1.0% sodium alginate solution at 50°C for 60 seconds, then drained for 120 seconds. Subsequently, they were immersed in a 2.0% calcium chloride solution at room temperature for 40 seconds for cross-linking and curing. After removal, they were quickly rinsed with water for 15 seconds and drained, resulting in a uniform gel protective film (approximately 45 μm thick) on the surface.

[0046] Mix the above-treated salted egg yolk granules with regular Cantonese sausage filling at low speed for 2 minutes at a ratio of 11% of the total weight of the sausage filling, and then stuff the mixture into natural pig casings.

[0047] Drying process: First, 65℃, relative humidity RH 70%, wind speed 0.8 m / s, for 2.2 hours; then 51.0℃, for 50 hours, with RH decreasing from 60% to 45% in stages; finally 45℃, RH 40%, for 25 hours.

[0048] Comparative Example 1 Compared to Example 1, the only difference is that the gel membrane coating step is omitted (i.e., sodium alginate and calcium chloride treatment is not performed), and the salted egg yolk particles only undergo low-temperature and low-humidity pretreatment. The remaining processes and formulations are the same as in Example 1.

[0049] Comparative Example 2 Traditional process: Salted egg yolk particles are not pre-treated on the surface or coated with any protective film. They are directly mixed with minced meat and dried at a constant temperature of 55℃ for 72 hours using the traditional process.

[0050] Test case The salted egg yolk sausages obtained in the above embodiments and comparative examples were tested for indicators, as follows: 1. Integrity rate of salted egg yolk particles At least three sausages were randomly selected from the same batch of prepared sausages, and each was evenly sliced ​​into 5mm thick slices, resulting in at least 30 valid cross-sections. The sausage slices were laid flat on a white background, and images of all cross-sections were taken using a high-definition digital camera under fixed lighting and distance. The images were then manually interpreted by two trained evaluators.

[0051] Judgment criteria: Salted egg yolk particles are considered "intact" if their projected outline basically maintains the original cut cubic shape (such as a square or rectangle), with clear edges and no obvious breakage, collapse, or mixing with the meat filling to the point that the boundaries are indistinguishable. For particles with blurred boundaries, calipers can be used for measurement. If their dimensions in both vertical directions are greater than 70% of the original cut size (such as 10mm) and their shape is roughly regular, they can also be considered intact.

[0052] Salted egg yolk particle integrity rate = (total number of intact particles / total number of particles observed in cross-section) × 100%.

[0053] 2. Surface water activity Carefully separate the whole salted egg yolk particles from the finished or semi-finished product (particles treated before drying); use a precision scraper or blade to evenly scrape off 2g of surface material with a thickness of about 1.0±0.2mm from the surface of the particles. Quickly place the scraped surface material into the sample cup, ensuring the sample is flat, fills the sample cup completely, and has no gaps.

[0054] Quickly place the sample cup into the test chamber of the water activity meter, start the test according to the instrument's operating procedures, wait for the reading to stabilize at 25°C, and record the stable water activity reading. Perform each sample in parallel three times and take the average value.

[0055] 3. Oil seepage rate during the drying process Before the drying process begins, clean and dry the drying trays used to hold the sausages and weigh them. Lay a layer of aluminum foil of known weight on the drying trays to facilitate the collection of dripping grease. Record the total weight of the semi-finished sausages before they are put into the oven. After the drying process is completed, carefully collect all the grease that adheres to the surface of the sausages and drips onto the aluminum foil. You can gently wipe the sausages and scrape off the solidified grease on the aluminum foil. Weigh the collected oozing grease (W1).

[0056] Take salted egg yolk raw materials from the same batch as the production batch and homogenize them. Determine the percentage of fat content (C) according to the Soxhlet extraction method in GB 5009.6-2025 National Food Safety Standard - Determination of Fat in Food. Calculate the total weight (W0) of the salted egg yolk raw materials used and their theoretical total fat content (W0) based on the production formula. th = W0× C).

[0057] Oil penetration rate (%) = [W1 / W] th ] × 100%.

[0058] 4. Sensory evaluation The evaluation team consists of at least 10 trained and sensory-sensitive evaluators who are prohibited from eating or drinking (except for water) for one hour prior to the evaluation. Sample preparation: All sausages to be evaluated are cut into segments of similar length and weight and placed in separate heat-resistant steaming dishes labeled with random three-digit numbers. They are then steamed for 15 minutes. After steaming, they are immediately removed and allowed to cool to approximately 60°C. They are then uniformly sliced ​​into thin slices approximately 3 mm thick and placed in the corresponding numbered evaluation plates. It is essential to ensure that the time interval between the completion of cooking and the start of evaluation is consistent for all samples.

[0059] The evaluation process employed a completely blind test, with samples randomly numbered. The evaluation order was designed to be balanced to eliminate the order effect. A structured questionnaire was used, with core indicators including: ① Flavor layering: 1 point = flavor is singular or chaotic, indistinguishable; 3 points = two flavors can be perceived, but the integration is average, and the layers are vague; 5 points = flavor layers are very clear, with the sweet and salty wine aroma of the sausage and the oily and salty aroma of the salted egg yolk released sequentially and harmoniously. ② Oiliness: 1 point = very oily, with a strong lingering feeling in the mouth; 3 points = moderate oiliness; 5 points = refreshing, with almost no oiliness.

[0060] The evaluators tasted the samples one by one, rinsed their mouths with water during breaks, and scored independently. The mean score and standard deviation of each sample on each indicator were calculated to determine whether there were statistically significant differences in scores between different groups (p<0.05 was considered significant).

[0061] The test results are shown in Table 1.

[0062] Table 1 .

[0063] Results analysis: Particle integrity: The integrity rate of salted egg yolk particles in Examples 1-3 was significantly higher than that in the two comparative examples, approaching 99%, demonstrating the significant effectiveness of the dual protection strategy of "low-temperature and low-humidity pretreatment + gel protective film". Comparative Example 1 only underwent pretreatment, and although the integrity rate was improved, it was still insufficient, indicating that pretreatment alone cannot completely resist the mechanical forces in subsequent processing.

[0064] Oil barrier effect: The oil penetration rate of Examples 1-3 was extremely low (2.2%-2.8%), while the penetration rates of Comparative Example 1 and Comparative Example 2 using the conventional process were as high as 10.2% and 15.8%, respectively. This clearly demonstrates the continuous and effective physical barrier effect of the calcium alginate gel membrane throughout the drying process, which greatly reduces oil migration.

[0065] Sensory quality: The example group scored higher in "flavor layering" because the oil was effectively locked in, allowing the salted egg yolk flavor to be preserved more independently and forming a clearer layer with the sausage flavor. In terms of "greasiness," the example group scored significantly lower (more refreshing), and the sensory evaluation was completely consistent with the oil seepage rate data.

[0066] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A salted egg yolk sausage, characterized in that, The raw materials include Chinese sausage meat and salted egg yolk granules; wherein, the surface of the salted egg yolk granules has a reinforced surface layer formed by low temperature and low humidity treatment, and the surface of the granules is coated with a gel protective film formed by cross-linking of sodium alginate and calcium ions.

2. The salted egg yolk sausage as described in claim 1, characterized in that, The thickness of the gel protective film is 20-60 μm.

3. The salted egg yolk sausage as described in claim 1, characterized in that, The amount of salted egg yolk granules added accounts for 8%-12% of the total weight of the sausage filling.

4. A method for preparing salted egg yolk sausage, characterized in that, Includes the following steps: The surface of the salted egg yolk particles is pretreated to form a reinforced surface layer with higher mechanical strength than the inner core. The surface of the pretreated salted egg yolk particles is coated with a gel protective film formed by cross-linking sodium alginate and calcium ions to obtain the treated salted egg yolk particles. Mix the processed salted egg yolk granules with the sausage filling and stuff the mixture into sausage casings; The sausages are dried after being filled.

5. The preparation method according to claim 4, characterized in that, The surface pretreatment method is as follows: place the salted egg yolk particles in an environment with a temperature of 2-5℃ and a relative humidity of 25%-35% for 15-30 minutes to reduce the surface water activity to below 0.

65.

6. The preparation method according to claim 4, characterized in that, The coating method of the gel protective film is as follows: The pretreated salted egg yolk particles were immersed in a 1.0%-1.5% sodium alginate solution for 30-60 seconds and then filtered. Subsequently, they were immersed in a 2.0%-3.0% calcium chloride solution for cross-linking and curing for 20-40 seconds. After removal, rinse quickly with clean water and drain, forming a gel protective film on the surface of the particles.

7. The preparation method according to claim 6, characterized in that, The immersion temperature of the sodium alginate solution is 40-50℃.

8. The preparation method according to claim 6, characterized in that, The cross-linking and curing temperature of the calcium chloride solution is 20-25℃.

9. The preparation method according to claim 4, characterized in that, The drying process is as follows: Rapid setting stage: temperature 55-60℃, time 1.5-2.5h; Dehydration and maturation stage: temperature 50-55℃, time 40-50h; Stable drying stage: temperature 45-48℃, time 20-25h.

10. The preparation method according to claim 9, characterized in that, The temperature during the dehydration and maturation stage is 52-54℃.