A method for processing cooked mutton

Abstract

The present application relates to the technical field of food processing, and particularly relates to a processing method for cooked mutton, comprising the following steps: obtaining fresh mutton raw materials; performing pre-treatment before fermentation on the fresh mutton raw materials; adding a compound bacterial solution to the pre-treated fresh mutton raw materials and performing fermentation, so as to hydrolyze the amine substances in the mutton, and obtain fermented mutton; immersing the fermented mutton in a compound gel solution and performing vacuum impregnation, so as to selectively remove the free amine substances after fermentation, and obtain mutton with amine removed; after ingredient and curing treatment, the mutton with amine removed is cooked at 80 DEG C to 85 DEG C for 10 min to 15 min, and cooked mutton products are obtained; wherein the compound bacterial solution is composed of Staphylococcus carnosus, Pediococcus pentosaceus, Lactococcus lactis and calcium chloride solution. The present application degrades the branched short-chain fatty acids causing amine in mutton by the microbial amine reduction method, while the branched long-chain fatty acids with physiological activity are retained.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a processing method for cooked mutton. Background Technology

[0002] Branched-chain fatty acids (BCFAs) are a class of saturated fatty acids containing methyl or other alkyl side chains in their carbon chain backbone. They are widely found in bio-lipids in nature, especially in ruminant adipose tissue and dairy products, with most originating from bacteria in the animal's digestive system. Compared to straight-chain fatty acids, BCFAs exhibit superior physicochemical properties due to their unique molecular structure, including lower melting and freezing points, and enhanced oxidative and thermal stability. Furthermore, studies have confirmed that these substances possess physiological activities such as anti-cancer, anti-inflammatory, and lipid metabolism regulation, demonstrating significant application value in functional foods and pharmaceuticals. Ruminant animal products (such as beef, fat, and milk from cattle and sheep) are the main dietary source of BCFAs for humans. However, the consumption level of dairy products among Chinese residents is significantly lower than that in Europe and the United States, making the need to supplement related nutrients through the development of functional foods rich in BCFAs increasingly urgent. Against this backdrop, mutton, as an important ruminant meat resource, deserves special attention for its nutritional value and development potential.

[0003] Lamb is rich in high-quality protein, B vitamins, and essential trace elements such as iron, zinc, and selenium. It also boasts advantages such as low fat content, low cholesterol levels, and tender, easily digestible meat. In 2022, my country's total output of pork, beef, lamb, and poultry reached 96.63 million tons, with lamb production reaching 5.18 million tons, ranking first globally. However, lamb only accounted for 5.3% of total meat production, far lower than other livestock meats. This production bottleneck is directly related to insufficient consumption, and one of the core factors restricting consumption is the characteristic flavor of lamb—often described in international studies as "animal flavor," "rotten flavor," or "metallic flavor," while Chinese consumers generally refer to it as "muttony smell." This flavor has become a key limiting factor affecting consumer acceptance and industry development. Studies have shown that the gamey odor of mutton mainly originates from 4-alkyl branched-chain fatty acids deposited in adipose tissue, including 4-methyloctanoic acid (MOA), 4-ethyloctanoic acid (EOA), and 4-methylnonanoic acid (MNA). Although the absolute content of these compounds in the tissue is not high, their high volatility significantly affects flavor perception. Among them, MOA has the highest concentration and the lowest sensory threshold, contributing the most to the gamey odor; EOA is second; and MNA has a relatively smaller impact due to its large concentration fluctuations. Microbial deodorization technology has become a research hotspot in recent years due to its high safety, mild action, and significant effects. This technology involves inoculating specific bacterial fermentation agents, utilizing the secreted lipases to selectively degrade the gamey fatty acids, altering their configuration and form. Simultaneously, peptides, amino acids, and fatty acid degradation products generated from protein hydrolysis by proteases can form flavor substances through Maillard reactions and oxidation pathways, reducing the intensity of the gamey odor while maintaining the edible quality of mutton.

[0004] It is worth noting that branched-chain fatty acids (BCFAs) include a class of components with significant biological activity: 13-methyltetradecanoic acid (13-MTD). This substance is a long-chain saturated branched-chain fatty acid (15 carbon atoms in total, with a tetradecanoic acid parent structure and a methyl branch at the 13th carbon). Multiple studies have confirmed that it can effectively induce apoptosis in various types of human cancer cells, exhibiting strong anti-cancer activity. However, existing mutton-reducing technologies, particularly microbial methods, focus on degrading short-chain BCFAs that cause mutton odor, but simultaneously destroy other physiologically active long-chain BCFAs (such as 13-MTD), leading to the loss of nutritional functions in mutton. While reducing the mutton odor, no mechanism for retaining or enriching functional BCFAs has been established, limiting the development of high-value-added mutton products.

[0005] Chinese Patent Publication No. CN107801926A discloses a method for removing the mutton's odor and cooking it. The steps are as follows: (1) Cut the mutton into small pieces, soak it in lightly salted water for 8-12 minutes, and rinse it with water after taking it out; (2) Apply the mutton deodorizing agent to the rinsed mutton, let it stand for 5-10 minutes, soak it in water for 20-30 minutes, and rinse it with water again after taking it out; the deodorizing agent is composed of the following components in parts by weight: 3 parts alfalfa extract, 3 parts protease, 4 parts sodium bicarbonate, 2 parts soy isoflavones, and 1 part vitamin B12; (3) Boil the mutton in water at 80-95℃ for 4-8 minutes, and drain it after taking it out; (4) Steam the drained mutton with water, and stir-fry it after cooking with seasonings. In order to verify the effect of the present invention, the fatty acid content of fresh mutton and mutton treated by the method of the present invention was determined. The results showed that the method of the present invention can reduce the fatty acid content of fresh mutton by 88%-92%, and has a significant deacidification effect.

[0006] Therefore, the methods for removing the mutton's odor and cooking it have the following problems: the enzymatic deodorization method focuses on degrading the short-chain BCFAs that cause the odor, but it will simultaneously destroy other physiologically active long-chain BCFAs (such as 13-MTD), resulting in the loss of the mutton's nutritional functions. Summary of the Invention

[0007] Therefore, the present invention provides a processing method for cooked mutton to overcome the problem that in the prior art, the microbial deodorization method degrades the short-chain branched fatty acids that cause mutton odor, which simultaneously destroys other physiologically active long-chain branched fatty acids, resulting in the loss of the nutritional function of mutton.

[0008] To achieve the above objectives, the present invention provides a processing method for cooked mutton, comprising:

[0009] Step S1: Obtain fresh mutton raw material and pre-treat the fresh mutton raw material before fermentation to obtain pre-treated mutton raw material;

[0010] Step S2: Detect the initial concentration of muttony substances in the pretreated mutton raw material and cut it into pieces to obtain pretreated mutton chunks. The size of the pretreated mutton chunks and the fermentation time are determined based on the initial concentration of muttony substances.

[0011] Step S3: Add compound bacterial solution to the pretreated mutton chunks and ferment them to hydrolyze the mutton's gamey substances and obtain fermented mutton.

[0012] Step S4: Immerse the fermented mutton in a composite gel solution and vacuum impregnate it to selectively remove free muttony substances after fermentation, and obtain deodorized mutton. The pressure breathing interval during the gel deodorization process is determined based on the pre-treated mutton chunks and the meat looseness of the fermented mutton.

[0013] Step S5: After marinating the deodorized mutton with seasonings, steam it at 80°C to 85°C for 10 to 15 minutes to obtain the cooked mutton product.

[0014] The compound bacterial solution is composed of Staphylococcus carinatum, Pediococcus pentosaceus, Lactococcus lactis, and calcium chloride solution.

[0015] Furthermore, the mass ratio of Staphylococcus carinatum, Pediococcus pentosaceus, and Lactococcus lactis in the compound bacterial solution is 6:3:1, and the total mass of the compound bacterial solution is 0.1% to 1% of the mass of the fresh mutton raw material.

[0016] Furthermore, the composite gel solution is a citrus pectin-cellulose composite gel solution, wherein the mass ratio of citrus pectin to nanocellulose crystals is 3:1 to 5:1.

[0017] Further, in step S2, the confidence level of the initial mutton odor concentration is verified, and the cutting size and fermentation time of the pretreated mutton raw material are determined based on the verified initial mutton odor concentration, wherein the initial mutton odor concentration is the total concentration of 4-methyloctanoic acid and 4-ethyloctanoic acid.

[0018] Further, step S3 includes:

[0019] Step S31: The freeze-dried bacterial powder composed of Staphylococcus aureus, Pediococcus pentosaceus and Lactococcus lactis in a mass ratio of 6:3:1 is reconstituted with 0.1 mmol / L CaCl2 solution and activated at 32°C for 30 min to obtain the composite bacterial solution;

[0020] Step S32: Inject the compound bacterial solution into the fresh mutton raw material and let it stand at 4°C for 20 minutes to allow the compound bacterial solution to diffuse naturally in the fresh mutton raw material.

[0021] Step S33: Place the fresh mutton raw material after injecting the compound bacterial solution into a tumbler, add 2% salt, and tumble intermittently at a vacuum of -0.09MPa and 4°C to promote the penetration of the compound bacterial solution.

[0022] Step S34: Place the tumbled fresh mutton raw material in a fermentation chamber for fermentation to obtain the fermented mutton.

[0023] Further, step S34 includes:

[0024] Step S341: The environment is maintained at 30°C and 85% relative humidity for 1 to 2 hours to promote bacterial growth.

[0025] Step S342: Based on the fermentation time, fermentation is carried out in an environment with a temperature of 25°C and a relative humidity of 90% to hydrolyze the muttony odor substances through the specific lipase secreted by the cells.

[0026] Step S343: In an environment with a temperature of 50°C and a relative humidity of 75% for 20 to 30 minutes, non-specific enzymes are inactivated to obtain the fermented mutton.

[0027] Furthermore, step S342 also includes spraying atomized citric acid solution onto the fresh mutton raw material to increase the diacetyl production of the lactococcus lactis.

[0028] The amount of citric acid solution added is 0.2% of the total mass of the fresh mutton raw material.

[0029] Further, step S4 includes:

[0030] Step S41: Obtain the meat looseness of the pretreated mutton chunks and the meat looseness of the fermented mutton.

[0031] Step S42: Determine the corrected pressure breathing interval during the gel deodorization process based on the rate of change in meat tenderness and the baseline pressure breathing interval;

[0032] Step S43: Immerse the fermented mutton in the citrus pectin-cellulose composite gel solution under vacuum according to the modified pressure breathing interval;

[0033] Step S44: Monitor the turbidity of the citrus pectin-cellulose composite gel solution in real time;

[0034] Step S45: When the increase in turbidity exceeds the turbidity growth threshold, the soaking is terminated to obtain the deodorized mutton.

[0035] Furthermore, the rate of change in the degree of meat loosening is determined based on the ratio of the degree of meat loosening of the pretreated mutton chunks to the degree of meat loosening of the fermented mutton.

[0036] Furthermore, step S45 also includes:

[0037] After soaking is terminated, the concentration of surface and internal mutton odor substances in the deodorized mutton is measured. The odor ratio is determined based on the surface and internal mutton odor substance concentrations, and the basal pressure breathing interval is adjusted for the next gel deodorization process.

[0038] The turbidity growth threshold is set based on the verified initial concentration of the odorant.

[0039] Compared with the prior art, the beneficial effect of the present invention is that while efficiently degrading the short-chain branched fatty acids that cause mutton odor in mutton, it selectively retains and enriches the long-chain branched fatty acids (13-MTD) with anti-cancer activity, thereby achieving a synergistic improvement in mutton odor suppression and functional component enhancement, breaking through the bottleneck of existing mutton odor reduction technology in terms of damage to nutritional active components.

[0040] Furthermore, this invention utilizes short-chain specific lipases secreted by Staphylococcus aureus to directionally hydrolyze 4-methyloctanoic acid (MOA) and 4-ethyloctanoic acid (EOA) and other muttonylic acid-causing substances, combined with the acid production of Pediococcus pentosus to inhibit the synthesis of muttony odor precursors, thereby achieving deep degradation of muttony odor substances. At the same time, esters and ketones produced by the metabolism of the microbial community synergistically enhance the richness and mellowness of the meat flavor, eliminating the chemical residues and off-flavors of traditional processes.

[0041] Furthermore, this invention ensures thorough deodorization and universal retention of nutritional activity by adjusting the fermentation time and turbidity threshold in real time based on the initial odor concentration.

[0042] Furthermore, the present invention utilizes the diacetyl generated by the metabolism of Lactococcus lactis to form a heat-stable adduct with 13-MTD. This adduct maintains its structural integrity during subsequent cooking and gelation processes, avoiding hydrolysis by other enzymes. After entering the human intestine, the adduct is specifically recognized by β-oxidase and releases free 13-MTD, ensuring the bioavailability of its anticancer activity.

[0043] Furthermore, this invention utilizes a calcium ion-activated citrus pectin-cellulose composite gel network to selectively capture free odor substances through a dual action of pore size sieving and chemical bonding, while physically preventing the loss of functional components.

[0044] Furthermore, this invention achieves a precise balance between deodorization and nutrient retention by dynamically setting the fermentation time and turbidity growth threshold based on the initial odor concentration. At the same time, the secondary utilization of calcium ions in enzyme activation and gel cross-linking significantly reduces the cost of auxiliary materials and avoids the problem of texture hardening caused by excessive addition.

[0045] Furthermore, this invention utilizes the protease secreted by Pediococcus pentosaceus to soften muscle fiber bundles, thereby enhancing the tenderness and juiciness of cooked mutton. Simultaneously, the acidic environment created inhibits the proliferation of spoilage bacteria, extends the product's shelf life, and reduces reliance on preservatives. Attached Figure Description

[0046] Figure 1 This is a flowchart of the processing method for cooked mutton according to the present invention;

[0047] Figure 2 This is a flowchart of step S3 of the processing method for cooked mutton according to the present invention;

[0048] Figure 3This is a flowchart of step S34 of the processing method for cooked mutton according to the present invention;

[0049] Figure 4 This is a flowchart of step S5 of the processing method for cooked mutton according to the present invention. Detailed Implementation

[0050] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0051] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0052] Please see Figures 1-4 The flowcharts shown are respectively the processing method for cooked mutton according to the present invention, the processing method for cooked mutton according to the present invention step S3, the processing method for cooked mutton according to the present invention step S34, and the processing method for cooked mutton according to the present invention step S5. The processing method for cooked mutton according to an embodiment of the present invention includes:

[0053] Step S1: Obtain fresh mutton raw material and pre-treat the fresh mutton raw material before fermentation to obtain pre-treated mutton raw material;

[0054] In one specific embodiment, six-month-old Albas cashmere goats were selected. The pretreatment before fermentation was as follows: the carcass was aged at 0℃~4℃ for 24 hours after slaughter, the hind leg meat or tenderloin was taken, visible fat and fascia were removed, and the meat was immersed in water containing 1% sodium bicarbonate at 4℃. The meat was then treated with a vacuum curing machine (-0.05MPa, pressure breathing interval 1min) for 10min~15min to remove blood and some precursors of muttony smell.

[0055] Understandably, the pre-fermentation process, using a vacuum marinating machine to create negative pressure, causes air to expand and escape from the interstitial spaces of the mutton tissue, while simultaneously damaging some cell structures and increasing tissue porosity. Periodic pressure changes accelerate solution penetration and squeeze out internal blood. At the same time, sodium bicarbonate, once dissolved, becomes weakly alkaline. This alkaline environment alters the structure of muscle proteins, causing myofibrils to swell and become looser, which increases the water-holding capacity and permeability of the muscle tissue. More importantly, the alkaline environment can slightly hydrolyze fats (producing free fatty acids) and neutralize some free acidic muttony odor substances, helping to convert some fat-soluble muttony odor precursors into more water-soluble forms (such as fatty acid salts).

[0056] Step S2: Detect the initial concentration of muttony substances in the pretreated mutton raw material and cut it into pieces to obtain pretreated mutton chunks. The size of the pretreated mutton chunks and the fermentation time are determined based on the initial concentration of muttony substances.

[0057] Specifically, in step S2, the confidence level of the initial mutton odor concentration is verified, and the cutting size and fermentation time of the pretreated mutton raw material are determined based on the verified initial mutton odor concentration. The initial mutton odor concentration is the total concentration of 4-methyloctanoic acid and 4-ethyloctanoic acid.

[0058] In one specific embodiment, 100g of mutton subcutaneous fat sample was taken, and the concentration of short-chain mutton odor substances in the sample was detected by gas chromatography-mass spectrometry (GC-MS) as the initial mutton odor substance concentration of the pretreated mutton raw material.

[0059] Preferably, the detection process for the concentration of the short-chain odor substance is as follows: the sample is crushed, homogenized at 5000 r / min for 5 min, wrapped in filter paper and placed in a Soxhlet extractor, and extracted continuously at a constant temperature of 60°C for 6 h using petroleum ether as solvent. The organic solvent in the extract is removed by a rotary evaporator to obtain a transparent and viscous crude fatty oil.

[0060] The initial concentration of mutton odor substances in the pretreated fresh mutton raw material was obtained by gas chromatography-mass spectrometry. Preferably, the chromatographic column was: Temperature program: initial temperature 100℃, hold for 2 min, increase to 220℃ at 6.0℃ / min, hold for 10 min; carrier gas (He) flow rate 1.0 mL / min, injection port temperature 270℃; split ratio 10:1; sample injection volume 1.0 μL; transfer line temperature 230℃; ion source temperature 220℃; electron impact (EI) ion source; electron energy 70 eV; selective ion scanning mode (SIM); data were processed and statistically analyzed using a gas chromatography-mass spectrometry (GC-MS) workstation to obtain the total concentration of 4-methyloctanoic acid (MOA) and 4-ethyloctanoic acid (EOA), which was recorded as the initial concentration of odor substances.

[0061] Preferably, the confidence level verification is a Grubbs test, α=0.05. After removing outliers, the mean is taken as the initial concentration of the muttony smell substance after verification, denoted as C0, with the unit being mg / kg.

[0062] It is understood that the above-described embodiments are existing technologies, and those skilled in the art can make adaptive adjustments to the methods and parameters of the above-described embodiments according to the actual situation, which will not be elaborated here.

[0063] In one specific embodiment, when cutting the mutton raw material into pieces, it is preferred to cut along the direction perpendicular to the muscle texture to avoid damaging the integrity of the muscle fibers; after cutting, it is quickly placed in a 4°C environment to prevent the oxidation of mutton odor precursors.

[0064] The specific formula for calculating the cut size of the pre-treated mutton raw material is as follows:

[0065] ;

[0066] Among them, L max This refers to the maximum size of the cut mutton pieces, that is, the maximum value of any dimension of the cut mutton pieces, whether it is the length, width, or height, expressed in centimeters (cm).

[0067] Understandably, at low concentrations, the larger meat chunk size (8cm) preserves the integrity of the muscle structure, avoids excessive cutting leading to juice loss, and simultaneously meets the basic penetration requirements of the bacterial solution. At high concentrations, the smaller meat chunk size (5cm) exposes more fat interfaces, allowing the Staphylococcus aureus lipase in the compound bacterial solution to fully contact the odor precursors and solve the problem of incomplete degradation of deep fats. Traditional fixed-size cutting in high-odor raw materials easily results in "surface deodorization but core residue," while dynamic size adjustment significantly improves the uniformity of deodorization. At the same time, the chunk size is a prerequisite for subsequent "meat looseness" testing. Under a unified size benchmark, the degree of muscle fiber relaxation caused by tumbling and fermentation is comparable. When the size is too large, the looseness test is easily interfered with by edge effects, leading to distortion of the vacuum impregnation breathing interval calculation. This provides accurate input for subsequent "pressure breathing interval correction based on meat looseness," avoiding a decrease in gel adsorption efficiency.

[0068] In a specific embodiment, the formula for calculating the fermentation time is as follows:

[0069] ,

[0070] Where T represents the fermentation time, in hours (h).

[0071] Understandably, based on publicly available data, consumers can accept a odor concentration of ≤6mg / kg, and during processing, it must be reduced to at least 10% below this value, i.e., ≤0.6mg / kg;

[0072] In the formula, based on several historical experimental data, when the initial concentration C0 ≤ 20 mg / kg, 2 hours of fermentation can reduce the concentration of mutton odor substances to 0.6 ± 0.08 mg / kg (meeting the standard); 0.04 is the overall enzymatic hydrolysis rate of MOA and EOA measured based on several historical experimental data. When the initial concentration C0 > 20 mg / kg, the fermentation time needs to be extended; 100 mg / kg is the metabolic saturation point of the microbial community measured based on historical experimental data. When C0 = 100 mg / kg, the maximum allowable fermentation time of 6.2 hours is reached.

[0073] It is understandable that the concentration of mutton odor substances (total concentration of MOA and EOA) can vary from 10mg / kg to 200mg / kg depending on breed, age of sheep, feed and part of the sheep. If a uniform fermentation time is used, when the concentration of mutton odor substances is low, over-fermentation will cause 13-MTD to be hydrolyzed by miscellaneous enzymes. When the concentration of mutton odor substances is high, insufficient enzymatic hydrolysis will lead to excessive mutton odor residue.

[0074] Step S3: Add compound bacterial solution to the pretreated mutton chunks and ferment them to hydrolyze the mutton's gamey substances and obtain fermented mutton.

[0075] The compound bacterial solution is composed of Staphylococcus carinatum, Pediococcus pentosaceus, Lactococcus lactis, and calcium chloride solution.

[0076] Specifically, the mass ratio of Staphylococcus carinatum, Pediococcus pentosaceus, and Lactococcus lactis in the compound bacterial solution is 6:3:1, and the total mass of the compound bacterial solution is 0.1% to 1% of the mass of the fresh mutton raw material.

[0077] Specifically, step S3 includes:

[0078] Step S31: The freeze-dried bacterial powder composed of Staphylococcus aureus, Pediococcus pentosaceus and Lactococcus lactis in a mass ratio of 6:3:1 is reconstituted with 0.1 mmol / L CaCl2 solution and activated at 32°C for 30 min to obtain the composite bacterial solution;

[0079] In one specific embodiment, the Staphylococcus aureus, the Pediococcus pentosaceus, and the Lactococcus lactis are derived from the China Industrial Microbial Culture Collection Center (CICC). The culture collection number of Staphylococcus aureus is CICC25173, that of Pediococcus pentosaceus is CICC 22227, and that of Lactococcus lactis is CICC25270.

[0080] Step S32: Inject the compound bacterial solution into the fresh mutton raw material and let it stand at 4°C for 20 minutes to allow the compound bacterial solution to diffuse naturally in the fresh mutton raw material.

[0081] In one specific embodiment, the compound bacterial solution is evenly injected into mutton tissue using a multi-needle syringe. After injection, the meat is placed in a 4°C environment and left to stand for 20 minutes. The temporary expansion of the intermuscular fiber gaps under low temperature conditions (expansion rate of 18% to 22%) promotes the natural penetration of the bacterial solution along the muscle perimysium. Preferably, the injection depth is 2 cm to 3 cm and the number of injection points is 10.

[0082] Step S33: Place the fresh mutton raw material after injecting the compound bacterial solution into a tumbler, add 2% salt, and tumble intermittently at a vacuum of -0.09MPa and 4°C to promote the penetration of the compound bacterial solution.

[0083] In one specific embodiment, mutton injected with bacterial solution is placed into a tumbler, and edible salt equal to 2% of the weight of the fresh mutton is added. The tumbler is then intermittently tumbled under a vacuum of -0.09 MPa and a temperature of 4°C. Preferably, the tumbler is paused for 5 minutes every 10 minutes of operation, for a total duration of 40 minutes.

[0084] Understandably, the vacuum environment creates a negative pressure gradient between myofibrils, increasing the rate of bacterial permeation and ensuring that the bacteria are evenly distributed deep within the muscle.

[0085] Step S34: Place the tumbled fresh mutton raw material in a fermentation chamber for fermentation to obtain the fermented mutton.

[0086] Specifically, step S34 includes:

[0087] Step S341: The environment is maintained at 30°C and 85% relative humidity for 1 to 2 hours to promote bacterial growth.

[0088] It is understandable that step S341 is the activation period of enzymatic hydrolysis, which is used to promote cell growth and secretion of basic enzyme systems.

[0089] Step S342: Based on the fermentation time, fermentation is carried out in an environment with a temperature of 25°C and a relative humidity of 90% to hydrolyze the muttony odor substances through the specific lipase secreted by the cells.

[0090] Specifically, step S342 further includes spraying atomized citric acid solution onto the fresh mutton raw material to increase the diacetyl production of the lactococcus lactis.

[0091] The amount of citric acid solution added is 0.2% of the total mass of the fresh mutton raw material.

[0092] Understandably, the citric acid solution provides Lactococcus lactis with a carbon source other than glucose, which produces additional pyruvate through lysis, artificially increasing the supply of pyruvate in the cell. This "forces" Lactococcus lactis to shift its metabolic flow more towards the α-acetolactate synthesis pathway, ultimately leading to a significant increase in diacetyl production.

[0093] It is understandable that step S342 is the target phase of enzymatic hydrolysis, used to induce specific lipases to hydrolyze the muttony odor substances, while protecting 13-MTD by forming a thermostable adduct between diacetyl produced by Lactococcus lactis and the carboxyl group of 13-MTD.

[0094] Step S343: The non-specific enzymes are inactivated by maintaining an environment at 42°C and 75% relative humidity for 20 to 30 minutes to obtain the fermented mutton.

[0095] It is understandable that step S343 is the termination period of enzymatic digestion, used to inactivate non-specific enzymes.

[0096] It is understandable that Staphylococcus aureus secretes short-chain specific lipases that preferentially degrade MOA / EOA (chain length C8, C10). Meanwhile, Staphylococcus aureus is placed in a 0.1 mmol / L Ca solution. 2+ In solution, induced expression of Ca 2+ Dependent lipase, enhancing its selectivity for MOA / EOA (Ca... 2+ (It chelates with branched carboxyl groups) to achieve efficient degradation of short-chain muttony substances.

[0097] Lactococcus lactis synthesizes large amounts of diacetyl via a citric acid fortification pathway. This substance forms a thermostable adduct with the carboxyl group of 13-MTD. The ketone group of diacetyl encapsulates the carboxyl group of 13-MTD, blocking the catalytic site of lipase. At the same time, the resulting adduct has a melting point of 85℃~90℃, making it resistant to subsequent cooking processes. After human ingestion, in the small intestine, intestinal β-oxidase specifically recognizes the ketone-enol structure of the adduct, hydrolyzes it to release free 13-MTD. The diacetyl protection mechanism only changes the physical form of 13-MTD (resisting digestive degradation) without destroying its chemical structure and biological function. Ultimately, it is efficiently released and absorbed in the intestine, and its nutritional value is fully preserved.

[0098] Pediococcus pentosaceus lowers the pH to 5.4–5.6 by producing acid, inhibiting the synthesis of branched-chain aldehydes, a precursor to the gamey odor. At the same time, its secreted proteases break down myofibrillar protein, thus improving the tenderness of the meat.

[0099] Step S4: Immerse the fermented mutton in a composite gel solution and vacuum impregnate it to selectively remove free muttony substances after fermentation, and obtain deodorized mutton. The pressure breathing interval during the gel deodorization process is determined based on the pre-treated mutton chunks and the meat looseness of the fermented mutton.

[0100] Specifically, the composite gel solution is a citrus pectin-cellulose composite gel solution, wherein the mass ratio of citrus pectin to nanocellulose crystals is 3:1 to 5:1.

[0101] Specifically, step S4 includes:

[0102] Step S41: Obtain the meat looseness of the pretreated mutton chunks and the meat looseness of the fermented mutton.

[0103] In one specific embodiment, a texture analyzer puncture probe (3 mm in diameter) was used to vertically puncture the center of the pretreated mutton chunks at a rate of 1 mm / s, avoiding puncturing fat or fascia. The peak puncture force (unit: N) was recorded, and the average value was taken after three repetitions. This value was recorded as the looseness degree D1 of the pretreated mutton chunks (this embodiment was completed before the mutton was fermented to remove the muttony smell). The center puncture force of the fermented mutton chunks was measured in the same way and recorded as the looseness degree D2 of the fermented mutton chunks.

[0104] Understandably, the peak puncture force directly represents the degree of loosening; the smaller the force value, the softer the meat.

[0105] Step S42: Determine the corrected pressure breathing interval during the gel deodorization process based on the rate of change in meat tenderness and the baseline pressure breathing interval;

[0106] Specifically, the rate of change in meat tenderness is determined based on the ratio of the meat tenderness of the pretreated mutton chunks to the meat tenderness of the fermented mutton.

[0107] In a specific embodiment, the formula for calculating the rate of change of meat tenderness is as follows:

[0108] ,

[0109] Where R is the rate of change of meat tenderness, which is dimensionless.

[0110] Understandably, the R value characterizes the degree of meat deterioration caused by fermentation; the further R is from 1, the greater the degree of meat deterioration caused by fermentation.

[0111] In one specific embodiment, the formula for calculating the corrected pressure breathing interval is as follows:

[0112] ,

[0113] Wherein, t1 is the modified pressure breathing interval, in minutes (min); t0 is the basic pressure breathing interval, in minutes (min), preferably 5 min for the first preparation of deodorized mutton; f is the looseness response coefficient, in minutes (min), with a value range of 0.5 min to 2 min, preferably 1.5 min.

[0114] Step S43: Immerse the fermented mutton in the citrus pectin-cellulose composite gel solution under vacuum according to the modified pressure breathing interval;

[0115] In one specific embodiment, a vacuum pickling machine is used with a vacuum pressure of -0.05 MPa; the vacuum is drawn to the target pressure, maintained for t1 time, and then released to normal pressure and maintained for 10 seconds; the vacuum pickling ends when the increase in turbidity exceeds the turbidity growth threshold.

[0116] Understandably, the rate of change in meat tenderness (R) is a direct quantitative indicator of changes in the myofibril network structure. During fermentation, the protease secreted by Pediococcus pentosus hydrolyzes myofibrillar proteins (such as myosin cross-links), leading to an expansion of the intermuscular gaps (manifested as a decrease in puncture force D2, R < 1). This structural change directly affects the permeation efficiency of the gel solution under vacuum conditions. An R value close to 1 indicates that the meat remains very firm after enzymatic hydrolysis, with minimal changes in the intermuscular gaps. This results in greater resistance to the diffusion of gel molecules into the meat, requiring a smaller pressure breathing interval to enhance the external gel renewal frequency and prevent surface adsorption saturation. The smaller the R value, the longer the single vacuum treatment time needs to be to ensure sufficient infiltration. The coefficient f is set based on a mathematical model constructed from the gel diffusion rate, diffusion coefficient, and myofibril porosity. Its range and optimal value are determined based on several historical experimental data, which will not be elaborated here.

[0117] In one specific embodiment, the composite gel solution is prepared as follows:

[0118] Citrus pectin (esterification degree ≤ 50%) and nanocellulose crystals (diameter 50±10nm) were mixed at a mass ratio of 3:1 to 5:1; deionized water was added to prepare a 5% (w / v) gel solution, and the pH was adjusted to 5.5±0.1 (citric acid-sodium citrate buffer system); 0.05mol / L CaCl2 was added to initiate cross-linking to obtain the citrus pectin-cellulose composite gel solution.

[0119] The fermented mutton is immersed in a composite gel solution and vacuum impregnated according to the modified pressure breathing interval; preferably, the meat-to-liquid ratio is 1:2, that is, 2L of composite gel solution is used for every 1kg of fermented mutton.

[0120] It is understandable that citrus pectin is rich in galacturonic acid, whose free carboxyl group (-COOH) ionizes into -COO at pH 5.5. - It forms ionic bonds with the free short-chain muttony odor substances (MOA / EOA, containing carbonyl groups) after enzymatic hydrolysis.

[0121] Cellulose nanocrystals can construct porous networks of 5nm–10nm. MOA / EOA molecules (≈1.2nm) easily enter the pores, while 13-MTD (≈1.8nm) can be partially blocked. This can be achieved through Ca... 2+ Cross-linking with pectin carboxyl groups forms an "egg-box structure," shrinking the gel pore size from 5nm-10nm to 2nm-3nm, completely blocking the entry of 13-MTD (molecular size ≈ 1.8nm).

[0122] This invention utilizes a citrus pectin-cellulose composite gel to selectively adsorb free short-chain odor substances after enzymatic hydrolysis, achieving a thorough removal of the odor. Simultaneously, it employs Ca... 2+ Cross-linked pectin-cellulose, a physical barrier method that shrinks the gel pore size, retains 13-MTD in the flesh.

[0123] Step S44: Monitor the turbidity of the citrus pectin-cellulose composite gel solution in real time;

[0124] In one specific embodiment, an online turbidity meter (such as HACH 2100N) is used to detect the turbidity of the solution in real time, in NTU; data is recorded every 2 minutes, and a turbidity-time curve is plotted.

[0125] Step S45: When the increase in turbidity exceeds the turbidity growth threshold, the soaking is terminated to obtain the deodorized mutton.

[0126] Specifically, step S45 further includes:

[0127] After soaking is terminated, the concentration of muttony substances on the surface and inside of the deodorized mutton is measured. The uniformity of deodorization is determined based on the concentration of muttony substances on the surface and inside, and the basal pressure breathing interval is adjusted in the next gel deodorization process.

[0128] The turbidity growth threshold is set based on the verified initial concentration of the odorant.

[0129] In one specific embodiment, the formula for calculating the turbidity growth threshold is as follows:

[0130] ,

[0131] Wherein, Z is the turbidity growth threshold in NTU; k is the turbidity linearity coefficient in NTU·kg / mg, with a value range of 0.7NTU·kg / mg to 0.9NTU·kg / mg, preferably 0.8NTU·kg / mg; and a is the background calibration constant in NTU, preferably 6NTU.

[0132] Understandably, the turbidity linearity coefficient k was calibrated based on several historical experimental data. At turbidity, approximately adsorption Gel; the background calibration constant 'a' is determined based on several historical experimental data. It represents the extreme value of turbidity fluctuation in the blank gel solution to avoid accidental termination.

[0133] It is understandable that the increase in turbidity directly reflects the amount of odorous substances adsorbed by the gel. When the increase in turbidity exceeds the turbidity growth threshold, it indicates that the gel adsorption is close to saturation. Continued soaking can easily lead to the dissociation of adsorbed MOA and the physical retention of 13-MTD due to prolonged contact.

[0134] In one specific embodiment, the surface 2 mm of tissue from a 50g piece of deodorized mutton was taken, and the concentration of surface muttony substances was measured using the same method as in step S2, denoted as C1; the central part of a 50g piece of deodorized mutton (avoiding the injection path) was taken, and the concentration of internal muttony substances was measured using the same method as in step S2, denoted as C. 2，

[0135] ,

[0136] in, , is the basal pressure breathing interval for the next gel deodorization process, in minutes (min); b is the uniformity adjustment coefficient, with a value ranging from 0.05 to 0.15, preferably, the uniformity adjustment coefficient b is 0.1.

[0137] It is understandable that the ratio of the surface muttony smell concentration to the internal muttony smell concentration, i.e., the muttony smell removal uniformity, is the core indicator characterizing the uniformity of gel muttony smell removal. When the muttony smell removal uniformity > 1, it indicates that the surface muttony smell residue is higher than the interior, reflecting that the vacuum breathing interval is too short, causing the gel to only be renewed on the surface, and the deep muttony smell substances are not fully adsorbed. When the muttony smell removal uniformity < 1, it indicates that the internal muttony smell removal is insufficient, reflecting that the single vacuum treatment time is too long, causing the gel to saturate prematurely on the surface. The introduction of the logarithmic function correction model stems from the nonlinear relationship between gel adsorption efficiency and muttony smell concentration gradient. When the surface muttony smell concentration is the same as the internal muttony smell concentration (i.e., the muttony smell removal uniformity equals 1), it indicates that the baseline pressure breathing interval is already optimal and no further adjustment is needed. The optimal value of b, 0.10, was calibrated through several muttony smell removal uniformity tests, which will not be elaborated here.

[0138] Step S5: After marinating the deodorized mutton with seasonings, steam it at 80°C to 85°C for 10 to 15 minutes to obtain the cooked mutton product. Example 1

[0139] Six-month-old Albas cashmere goats from the same batch were selected. After slaughter, the carcasses were aged at 4°C for 24 hours. The hind leg meat was taken, and visible fat and fascia were removed. The meat was then immersed in water containing 1% sodium bicarbonate at 4°C and treated for 10 minutes using a vacuum curing machine (-0.05MPa, pressure breathing interval of 1min). The initial concentration of odor substances (MOA+EOA) was measured to be 23.6mg / kg, and the data was confirmed to be valid by Grubbs test.

[0140] Based on the initial concentration of 23.6 mg / kg, the calculated cut size is 8 cm, and the pieces are cut into pieces accordingly.

[0141] Based on the initial concentration of 23.6 mg / kg, the fermentation time was calculated to be 2.144 h according to the formula;

[0142] Based on the initial concentration of 23.6 mg / kg, the turbidity growth threshold calculated using the formula is 24.88 NTU;

[0143] The looseness D1 of the pretreated mutton chunks was determined to be 41N using a texture analyzer with a puncture probe.

[0144] Weigh out the freeze-dried bacterial powder (Staphylococcus carinatum: Pediococcus pentosaceus: Lactococcus lactis = 6:3:1 mass ratio), the total amount being 0.6% of the mutton mass. Redissolve in 0.1 mmol / L CaCl2 solution and activate in a 32℃ constant temperature water bath for 30 min;

[0145] The bacterial solution was injected using a multi-needle syringe (2.5 cm deep, 10 injection points) and allowed to stand at 4°C for 20 minutes.

[0146] Add 2% salt by weight of mutton and knead intermittently under vacuum of -0.09 MPa and 4°C (work for 10 minutes, pause for 5 minutes, total time 40 minutes).

[0147] Maintain a temperature of 30℃ and a relative humidity of 85% for 1.5 hours;

[0148] The temperature was 25℃ and the relative humidity was 90% for 2.144 hours, during which time a 0.2% citric acid solution was sprayed.

[0149] Treat at 42℃ and 75% relative humidity for 25 minutes;

[0150] The degree of loosening (D2) of fermented mutton was determined to be 34 N using a texture analyzer puncture probe.

[0151] Based on D1 and D2, the corrected pressure breathing interval is calculated to be 5.26 min using the formula.

[0152] Citrus pectin (45% esterification) and nanocellulose crystals were mixed at a mass ratio of 4:1 to prepare a 5% aqueous solution. 5 mmol / L calcium chloride was added to adjust the pH to 5.5.

[0153] Fermented mutton and gel liquid were placed in a vacuum marinating machine at a mass-to-volume ratio of 1:2 and soaked under a vacuum pressure of -0.05 MPa. The vacuum was then drawn to the target pressure and maintained for 5.26 min before being released to atmospheric pressure and maintained for 10 s. Turbidity was monitored in real time, and the soaking was terminated when the threshold of 24.88 NTU was reached (the actual turbidity at the termination was 25.1 NTU).

[0154] The uniformity of mutton removal was determined by measuring the concentration of surface and internal mutton odor substances in the deodorized mutton, with a value of 1.12.

[0155] Based on a deodorization uniformity of 1.12, the basal pressure breathing interval for the next gel deodorization process is calculated to be 5.06 min according to the formula.

[0156] Rinse with purified water, drain, marinate with ingredients, steam at 85℃ for 10 minutes, cool to room temperature and then package. Example 2

[0157] The initial concentration of the odor-causing substance was 25.2 mg / kg; the mass ratio of Staphylococcus carinatum: Pediococcus pentosaceus: Lactococcus lactis was 7:2:1, and the rest was the same as in Example 1. Example 3

[0158] The initial concentration of the odor-causing substance was 26.1 mg / kg; the mass ratio of Staphylococcus carinatum: Pediococcus pentosaceus: Lactococcus lactis was 5:4:1, and the rest was the same as in Example 1. Example 4

[0159] The initial concentration of the odor-causing substance was 22.2 mg / kg; the mass ratio of Staphylococcus carinatum: Pediococcus pentosaceus: Lactococcus lactis was 6.5:3:0.5, and the rest was the same as in Example 1. Example 5

[0160] The initial concentration of the odor-causing substance was 30.1 mg / kg; the mass ratio of Staphylococcus carinatum: Pediococcus pentosaceus: Lactococcus lactis was 5.5:4:0.5, and the rest was the same as in Example 1. Example 6

[0161] The initial concentration of the odor-causing substance was 28.8 mg / kg; the freeze-dried bacterial powder was prepared using a pure aqueous solution instead of a calcium chloride solution, and the rest was the same as in Example 1. Example 7

[0162] The initial concentration of the odor-causing substance was 20.5 mg / kg; the gel deodorization step was omitted, and the rest was the same as in Example 1. Example 8

[0163] The initial concentration of the odor-causing substance was 29.5 mg / kg; the fermentation time was fixed at 2 hours, and the rest was the same as in Example 1. Example 9

[0164] The initial concentration of the odor-causing substance was 16.2 mg / kg; the fixed turbidity threshold was 20 turbidity units, and the rest was the same as in Example 1. Example 10

[0165] The initial concentration of the odor-causing substance was 25.5 mg / kg; the pressure interval during gel deodorization was 5 min, and the rest was the same as in Example 1.

[0166] Detection method:

[0167] Detection of residual odor substances:

[0168] Methods: GB5009.168-2016 Gas chromatography-mass spectrometry;

[0169] Conditions: Column: DB-WAX (60m × 0.25mm × 0.25μm);

[0170] Temperature program: 50℃ (2 min) to 10℃ / min to 240℃ (10 min);

[0171] Quantitative ions: MOAm / z74, EOAm / z117.

[0172] 13-MTD Retention Rate Detection:

[0173] Methods: UPLC-MS / MS was used to detect the adducts (m / z 241.216 to 152.104).

[0174] Conditions: Column: ACQUITY UPLC BEH C18 (2.1×100mm, 1.7μm);

[0175] Mobile phase: A: 0.1% formic acid solution; B: acetonitrile;

[0176] Ion source: Electrospray negative ion (ESI) - ).

[0177] Hardness testing:

[0178] Instrument: Texture analyzer TA.XT Plus;

[0179] Parameters: Probe: P / 5 cylindrical (5 mm diameter), Test rate: 1 mm / s, Compression ratio: 50%;

[0180] Indicator: Peak force during initial compression.

[0181] Sensory evaluation:

[0182] Standard: GB / T 22210-2008 Sensory Evaluation Specification for Meat and Meat Products;

[0183] Indicators: Odor intensity (0-5 points), meat tenderness (0-5 points), total score (0-10 points);

[0184] Judging panel: 10 qualified trainees (double-blind test).

[0185] Please refer to Table 1 for the experimental results.

[0186] Table 1. Detection results of Examples 1-10

[0187] ;

[0188] This demonstrates that when the bacterial ratio strictly follows Staphylococcus carinatum: Pediococcus pentosaceus: Lactococcus lactis = 6:3:1 (Example 1), both the degradation rate of muttony odor substances and the retention rate of 13-MTD reach optimal levels. The dominant role of Staphylococcus carinatum ensures efficient hydrolysis of short-chain muttony acids; the appropriate proportion of Pediococcus pentosaceus maintains an acidic environment, inhibiting the synthesis of muttony odor precursors without affecting the symbiotic relationship of the microbial community; and the precise ratio of Lactococcus lactis ensures saturated diacetyl production, achieving complete protection of 13-MTD. Breaking this ratio (as in Examples 2-5) will trigger a chain reaction of imbalances: excessive Staphylococcus carinatum leads to excessive hydrolysis of the meat (abnormally increased firmness); insufficient Lactococcus lactis sharply reduces diacetyl synthesis, resulting in significant loss of 13-MTD during subsequent processing; and excessive Pediococcus pentosaceus causes excessively low pH, inhibiting the activity of the core lipase. This proves that the stated ratio is the balance point for synergistic microbial function.

[0189] In Example 6, where calcium ions were omitted, the residual odor increased several times over, and the 13-MTD retention rate plummeted. This stems from the absence of the dual effects of calcium ions: during fermentation, the calcium-deficient Staphylococcus aureus lipase cannot accurately identify short-chain odor acids, leading to a significant reduction in degradation efficiency; during the gel deodorization stage, the lack of calcium cross-linking enlarges the pore size of the pectin-cellulose network, resulting in a loss of size sieving ability, and short-chain odor acids are simultaneously adsorbed along with 13-MTD adducts. More seriously, the lack of calcium signaling leads to insufficient synthesis of diacetyl, and 13-MTD loses its protective barrier. This indicates that calcium ions are a key medium throughout the entire chain of "targeted deodorization—component protection."

[0190] The control groups with fixed fermentation time (Example 8) or fixed turbidity threshold (Example 9), while capable of processing raw materials with specific muttony odor concentrations, showed vulnerability to concentration fluctuations. The fixed fermentation time group resulted in incomplete degradation of high-odor muttony meat, while causing over-fermentation of low-odor muttony meat, leading to meat hardening. The fixed turbidity threshold group prematurely terminated deodorization in low-odor raw materials, leaving residual odor substances, while in high-odor raw materials, it caused gel adsorption saturation and rupture, resulting in the loss of functional components. Only by dynamically adjusting parameters based on the initial concentration, as in Example 1, can the deodorization requirements of different raw materials be accurately matched, achieving uniform quality.

[0191] In Example 7, which omitted the gel deodorization process, although the odor degradation met the standards during fermentation, the odor intensity rebounded after cooking, resulting in a significant deterioration in sensory scores. This is because the free odor substances remaining from fermentation volatilized and escaped during heat treatment. The composite gel, through a dual mechanism of "pore size sieving + chemical bonding," thoroughly captures free odor molecules, while its food-grade raw material properties avoid the risk of chemical solvent residue. More importantly, the gel treatment significantly improves meat tenderness because the microporous structure it forms promotes moisture retention, partially offsetting the muscle fiber contraction effect caused by fermentation.

[0192] In Example 10, where the calculation of the pressure interval during gel deodorization was omitted, the residual concentration of muttony substances rebounded to some extent compared to Example 1, and the 13-MTD retention rate also decreased. This indicates that the gel diffusion rate and the porosity of the muscle fibers of the enzymatically hydrolyzed mutton did not match well, resulting in insufficient gel penetration or saturation of gel surface adsorption, which in turn led to insufficient adsorption of free muttony substances and physical retention of some 13-MTD.

[0193] All control groups that modified the core process exhibited excessive total bacterial counts or flavor defects. For example, the calcium-free group required extended fermentation time due to insufficient lipase activity, leading to the proliferation of miscellaneous bacteria; the group with unbalanced microbial strains weakened its antibacterial ability due to improper pH control. Only by fully implementing this process (Example 1), through segmented fermentation temperature and timing control, citric acid-enhanced diacetyl synthesis, and the physical antibacterial barrier of the gel, can a balance between deep deodorization and microbial safety and flavor optimization be achieved.

[0194] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A processing method for cooked mutton, characterized in that, include: Step S1: Obtain fresh mutton raw material and pre-treat the fresh mutton raw material before fermentation to obtain pre-treated mutton raw material; Step S2: Detect the initial concentration of muttony substances in the pretreated mutton raw material and cut it into pieces to obtain pretreated mutton chunks. The size of the pretreated mutton chunks and the fermentation time are determined based on the initial concentration of muttony substances. Step S3: Add compound bacterial solution to the pretreated mutton chunks and ferment them to hydrolyze the mutton's gamey substances and obtain fermented mutton. Step S4: Immerse the fermented mutton in a composite gel solution and vacuum impregnate it to selectively remove free muttony substances after fermentation, and obtain deodorized mutton. The pressure breathing interval during the gel deodorization process is determined based on the pre-treated mutton chunks and the meat looseness of the fermented mutton. Step S5: After marinating the deodorized mutton with seasonings, steam it at 80°C to 85°C for 10 to 15 minutes to obtain the cooked mutton product. The compound bacterial solution is composed of Staphylococcus aureus, Pediococcus pentosaceus, Lactococcus lactis, and calcium chloride solution. The mass ratio of Staphylococcus aureus, Pediococcus pentosaceus, and Lactococcus lactis in the compound bacterial solution is 6:3:1, and the total mass of the compound bacterial solution is 0.1% to 1% of the mass of the fresh mutton raw material. The composite gel solution is a citrus pectin-cellulose composite gel solution, wherein the mass ratio of citrus pectin to nanocellulose crystals is 3:1 to 5:

1. In step S2, the confidence level of the initial mutton odor concentration is verified, and the cutting size and fermentation time of the pretreated mutton raw material are determined based on the verified initial mutton odor concentration. The initial mutton odor concentration is the total concentration of 4-methyloctanoic acid and 4-ethyloctanoic acid. Step S4 includes: Step S41: Obtain the meat looseness of the pretreated mutton chunks and the meat looseness of the fermented mutton. Step S42: Determine the corrected pressure breathing interval during the gel deodorization process based on the rate of change in meat tenderness and the baseline pressure breathing interval; Step S43: Immerse the fermented mutton in the citrus pectin-cellulose composite gel solution under vacuum according to the modified pressure breathing interval; Step S44: Monitor the turbidity of the citrus pectin-cellulose composite gel solution in real time; Step S45: When the increase in turbidity exceeds the turbidity growth threshold, the soaking is terminated to obtain the deodorized mutton. The rate of change in meat tenderness is determined based on the ratio of the meat tenderness of the pretreated mutton chunks to the meat tenderness of the fermented mutton. The turbidity growth threshold is set based on the verified initial concentration of the odor-causing substance; The specific formula for calculating the corrected pressure breathing interval is as follows: ， Where t1 is the corrected pressure breathing interval in minutes (min); t0 is the basic pressure breathing interval in minutes (min), and for the first preparation of deodorized mutton, it is taken as 5 min; f is the looseness response coefficient in minutes (min), and f is taken as 1.5 min.

2. The processing method for cooked mutton according to claim 1, characterized in that, Step S3 includes: Step S31: The freeze-dried bacterial powder composed of Staphylococcus aureus, Pediococcus pentosaceus and Lactococcus lactis in a mass ratio of 6:3:1 is reconstituted with 0.1 mmol / L CaCl2 solution and activated at 32°C for 30 min to obtain the composite bacterial solution; Step S32: Inject the compound bacterial solution into the fresh mutton raw material and let it stand at 4°C for 20 minutes to allow the compound bacterial solution to diffuse naturally in the fresh mutton raw material. Step S33: Place the fresh mutton raw material after injecting the compound bacterial solution into a tumbler, add 2% salt, and tumble intermittently at a vacuum of -0.09MPa and 4°C to promote the penetration of the compound bacterial solution. Step S34: Place the tumbled fresh mutton raw material in a fermentation chamber for fermentation to obtain the fermented mutton.

3. The processing method for cooked mutton according to claim 2, characterized in that, Step S34 includes: Step S341: The environment is maintained at 30°C and 85% relative humidity for 1 to 2 hours to promote bacterial growth. Step S342: Based on the fermentation time, fermentation is carried out in an environment with a temperature of 25°C and a relative humidity of 90% to hydrolyze the muttony odor substances through the specific lipase secreted by the cells. Step S343: In an environment with a temperature of 50°C and a relative humidity of 75% for 20 to 30 minutes, non-specific enzymes are inactivated to obtain the fermented mutton.

4. The processing method for cooked mutton according to claim 3, characterized in that, Step S342 further includes spraying atomized citric acid solution onto the fresh mutton raw material to increase the diacetyl production of the lactococcus lactis. The amount of citric acid solution added is 0.2% of the total mass of the fresh mutton raw material.

5. The processing method for cooked mutton according to claim 1, characterized in that, Step S45 further includes: After soaking is terminated, the concentration of muttony substances on the surface and inside of the deodorized mutton is measured. The muttony ratio is determined based on the concentration of muttony substances on the surface and inside, and the basal pressure breathing interval is adjusted in the next gel deodorization process.

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