High-freshness-retaining pickling method of duck gizzards

Abstract

The invention relates to the field of food processing, in particular to a high-freshness-retaining pickling method of duck gizzards. The preparation method comprises the following steps: screening and pre-treating, namely screening and pre-treating duck gizzards, and draining to obtain duck gizzards A; performing fishy smell removal and pre-pickling: kneading and stirring the duck gizzards A with pickling liquid for 3-5 minutes, taking out the duck gizzards A, and drying the duck gizzards A until the surface humidity is less than 30% to obtain duck gizzards B; performing fresh-keeping coating: performing double-sided spraying on the surfaces of the duck gizzards B through a fresh-keeping glue solution, and performing airing to obtain duck gizzards C; performing vacuum infiltration pickling: putting the duck gizzards C into the pickling liquid again, and performing vacuum infiltration pickling to obtain duck gizzards D; curing and sterilizing: mixing the duck gizzards D with marinating essence, cooking, cooling after cooking, adding a toner and a flavoring agent, uniformly mixing with the mixture, and sterilizing to obtain the high-freshness preserved duck gizzards; according to the process, the fullness and layering sense of the flavor of the finished product are enhanced through the three steps of deodorization and pre-pickling, fresh-keeping coating and vacuum infiltration pickling.

Description

Technical Field

[0001] This application relates to the field of food processing, and more specifically, to a method for preserving the freshness of duck gizzards through marinating. Background Technology

[0002] Poultry offal products, especially duck gizzards, are widely popular due to their unique taste and occupy a certain market share in the food processing industry. With consumers' increasing demands for food quality, the demand for high-quality duck gizzard products is growing, driving the continuous development of duck gizzard curing technology. However, the inherent strong odor of duck gizzards as offal, coupled with their dense muscle tissue, presents numerous challenges to the curing process, hindering the industrial production of high-quality duck gizzard products.

[0003] In existing technologies, two main methods are commonly used to remove the fishy smell and infuse flavor into the duck gizzards. One method involves prolonged soaking and marinating, using a high-concentration solution of salt, alcohol, and spices. This method utilizes the components of the marinade to remove the fishy smell and infuse flavor, allowing the marinade to fully penetrate the gizzard through prolonged soaking. The other method is high-intensity mechanical tumbling marinating, which uses a tumbler under normal pressure for extended periods to accelerate marinade penetration. This method uses mechanical force to allow the marinade to enter the gizzard more quickly, shortening the marinating time.

[0004] Existing technologies have significant drawbacks. Prolonged static soaking and marinating causes a large loss of valuable moisture, soluble proteins, free amino acids, and nucleotides—all essential umami substances—from the duck gizzard into the marinade, resulting in a dry, tough product with severe flavor loss, low yield, and low production efficiency. While high-intensity mechanical tumbling marinating can shorten the time, the intense mechanical action and full contact with air can easily lead to excessive damage to muscle fibers and increased product temperature, similarly exacerbating the loss of moisture and flavor substances, and potentially causing undesirable flavors due to oxidation. More importantly, incomplete initial deodorization can trap odorous substances inside the product during subsequent processing, resulting in an impure flavor. Therefore, existing technologies suffer from a difficulty in simultaneously achieving good taste, flavor, and efficiency. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical problems and provide a method for marinating duck gizzards with high preservation.

[0006] A high-preservation marinating method for duck gizzards is obtained through the following method: Screening and pretreatment: After screening and pretreatment, the duck gizzards are drained to obtain duck gizzard A; Pre-marinating to remove fishy smell: Mix duck gizzard A with the marinade for 3-5 minutes, then remove and dry until the surface moisture content is less than 30% to obtain duck gizzard B; Preservative coating: Apply a preservative adhesive to both sides of the surface of duck gizzard B, and let it dry to obtain duck gizzard C; Vacuum permeation marinating: Duck gizzard C is put back into the marinating liquid and tumbled and stirred at least once under vacuum. The tumbling and stirring process includes tumbling under vacuum for at least 10 minutes, then standing for at least 30 minutes, and then marinating at -2~2℃ for 2.5-4 hours to obtain duck gizzard D; Cooking and sterilization: Mix duck gizzards with braising spices and cook. After cooking, cool, add coloring agents and seasonings and mix evenly. Sterilize to obtain highly fresh marinated duck gizzards. The preservative adhesive solution is obtained by diluting a preservative adhesive in water. The preservative adhesive is composed of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan.

[0007] By adopting the above technical solution, the fishy smell can be efficiently removed in a stepwise manner while the flavor substances of duck gizzards are retained in a targeted manner. The initial pre-marinating process can effectively remove most of the fishy smell substances on the surface and shallow layer of the duck gizzards without causing a large loss of internal juices. The protective film formed by the subsequent preservation coating can effectively prevent the reverse diffusion of water-soluble flavor substances (free amino acids, flavor nucleotides) inside the duck gizzards into the marinating liquid, making the second marinating process an active flavor-enhancing process, which enhances the fullness and layering of the finished product's flavor. It can also synergistically optimize the texture and yield of duck gizzards, and the water-soluble mussel adhesive protein and carboxymethyl shell in the preservation gel can be combined to achieve the desired effect. The composite film formed by polysaccharides possesses barrier, water-retaining, and biocompatible properties. Combined with the vacuum permeation marinating process, it achieves "only flavor infusion and minimal water loss," resulting in a "crisp, chewy, and juicy" texture for the duck gizzards and increasing yield. The components of the preservative adhesive work synergistically: water-soluble mussel adhesive protein ensures complete coverage of the protective film, honey extract enhances the film's water retention, cellulose derivatives provide mechanical strength, and carboxymethyl chitosan imparts antibacterial properties to the film. Together with the low-temperature marinating process, they inhibit microbial growth, extend shelf life, and comprehensively ensure the stable quality of the duck gizzards from marinating to the finished product.

[0008] This composite membrane system is not an inert barrier. It interacts with the components on the surface of the duck gizzard and in the marinade to form a "dynamic preservation system". It comprehensively ensures the quality stability from marinating to the finished product from three dimensions: physical barrier, moisture retention and microbial inhibition.

[0009] In summary, this application has successfully and synergistically solved a series of interconnected technical problems in traditional methods, such as incomplete removal of fishy odor, severe loss of flavor, dry and hard texture, and low yield, through the creative combination of a specific pickling process and a specific preservative adhesive. The result is a high-preservation pickled duck gizzard product with full flavor, superior taste, and stable quality.

[0010] Preferably, the pickling solution is obtained by the following method: Weigh out the water-retaining agent and edible salt, dissolve them in water, add the flavoring agent, mix well, then add the deodorizing and preservative agent and mix well to obtain the pickling liquid.

[0011] The core advantage of the above technical solution lies in the specific formulation sequence design of the marinating liquid: by first constructing a stable water-retaining ion system, and then introducing flavor substances and easily deactivated deodorizing components step by step, this process is precisely coupled with the deodorizing pre-marinating and vacuum permeation marinating steps in the overall process. This design can optimize the action sequence and efficiency of each functional component at the molecular level, effectively avoiding mutual interference between different components, thereby achieving a synergistic effect of highly efficient deodorization, high moisture retention, and high flavor retention, providing core technical support for the stable quality of the final product.

[0012] Furthermore, the water-retaining agent is selected from soy protein isolate (CAS No. 9010-10-0). This type of soy protein isolate has excellent water-retaining and emulsifying properties. Its hydrophilic groups can firmly bind water, while its hydrophobic groups can promote the compatibility of oil and aqueous system. It forms a synergistic effect with other raw materials such as edible salt and flavoring agents in the pickling solution, significantly improving the overall effect of water locking, flavor adsorption and system stability during the pickling process.

[0013] Preferably, the amount of coating is controlled to be 5-8g of preservative adhesive per 100g of duck gizzard.

[0014] By adopting the above technical solution, the amount of preservative adhesive sprayed is controlled at 5-8g per 100g of duck gizzard. This creates a profound synergistic effect with the specially formulated preservative adhesive components and the unique "step-by-step marinating" process, which helps to obtain duck gizzard products with high water retention, high flavor retention rate, and excellent taste. This demonstrates the high creativity and precise controllability of the method. By combining screening and pretreatment, deodorizing pre-marinating, preservative coating, vacuum penetration marinating, maturation and sterilization, and specific preservative adhesives, efficient step-by-step deodorization and targeted retention of flavor substances can be achieved, optimizing texture and yield. The multifunctional synergistic effect of preservative adhesives can be leveraged to solve the problems of incomplete deodorization, serious flavor loss, dry and hard texture, and low yield in traditional methods, resulting in high-preservation marinated duck gizzard products with full flavor, superior taste, and stable quality.

[0015] Preferably, the flavoring agent is one or more of the following: white sugar, monosodium glutamate, and disodium inosinate.

[0016] By adopting the above technical solution, duck gizzards are first screened, pre-treated, deodorized and pre-marinated, coated with preservative, vacuum-permeable marinated, cooked and sterilized. A preservative adhesive solution is prepared by diluting a preservative adhesive composed of water-soluble mussel adhesive protein, honey extract, cellulose derivatives and carboxymethyl chitosan in water. Then, one or more of white sugar, monosodium glutamate and disodium inosinate are selected as flavoring agents. Combined with the step-by-step marinating process, preservative coating and precise order of feeding, multiple mechanisms such as biochemical umami synergy, sensory science taste balance and food chemical thermal reaction aroma generation work synergistically on the preserved duck gizzards to create a high-quality marinated duck gizzard product with rich and prominent umami, full and harmonious flavor layers and natural and rich aroma.

[0017] Preferably, the deodorizing and preservative is a combination of one or more of the following: white wine, ginger powder, deodorizing powder, and ethyl maltol.

[0018] By adopting the above technical solution, duck gizzards are screened, pre-treated, drained, kneaded with marinade for 3-5 minutes, dried until surface moisture is less than 30%, sprayed with preservative liquid on both sides and dried, then tumbled and stirred under vacuum, left to stand, and marinated at low temperature. Finally, they are cooked with braising essence, cooled, and then mixed with coloring agents and seasonings, sterilized, and the deodorizing and preservative agents are selected from one or more of the following: white wine, ginger powder, deodorizing powder, and ethyl maltol. This constitutes a multi-stage, multi-target, and functionally complementary synergistic deodorizing and preservative system. Through the synergistic effect of multiple physicochemical properties such as volatility, adsorption, masking, and antibacterial properties, and precisely embedded in the process framework of "pre-marinating-film formation-vacuum marinating", it achieves all-round and three-dimensional deodorizing and preservative effects from the surface to the inside and from physical to chemical, producing a synergistic effect and ultimately ensuring the high purity, fullness, and stability of the flavor of the finished duck gizzards.

[0019] Preferably, the colorant is red yeast rice and / or red chili pepper.

[0020] By adopting the above technical solution, in the cooking and sterilization steps of marinating duck gizzards, red yeast rice and / or red chili peppers are used as colorants. Combined with screening and pretreatment, deodorizing pre-marinating, preservation coating, vacuum penetration marinating and other steps, as well as preservation adhesive and marinating liquid composed of specific components and mixed in specific proportions, it can play a coloring role in marinating duck gizzards while achieving efficient step-by-step deodorization and targeted retention of flavor substances, synergistic optimization of texture and yield, and leveraging the multi-functional synergistic effect of preservation adhesives.

[0021] Preferably, the seasoning is oil-soluble chili oil and / or spicy compound oil.

[0022] Furthermore, by weight, the seasoning consists of 0.015 parts of oil-soluble chili oil and 0.15 parts of spicy compound oil.

[0023] By adopting the above technical solution, specifically selecting oil-soluble chili essential oil and / or spicy compound oil as seasonings, and combining them with the "step-by-step marinating" process and the "preservation coating" step, a multi-stage, multi-target, and functionally complementary synergistic deodorization and preservation system is formed. Through the synergistic effect of multiple physicochemical properties such as volatility, adsorption, masking, and antibacterial properties, and precisely embedded in the process framework of "pre-marinating-film formation-vacuum marinating", a comprehensive and three-dimensional deodorization and preservation is achieved from the surface to the inside, from physical to chemical, resulting in a synergistic effect and ultimately ensuring the high purity, fullness, and stability of the flavor of the finished duck gizzard.

[0024] Preferably, the weight ratio of the water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan is 1:(1-3):(2.5-5):(0.5-1).

[0025] By adopting the above technical solution, duck gizzards undergo screening and pretreatment, deodorizing pre-marinating, preservation coating, vacuum penetration marinating, maturation and sterilization. The preservation adhesive is prepared by diluting a water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan in a weight ratio of 1:(1-3):(2.5-5):(0.5-1) in water. This allows for efficient, stepwise deodorization and targeted retention of flavor substances in the duck gizzards, enhancing the fullness and complexity of the finished product's flavor. It also synergistically optimizes texture and yield, resulting in a "crisp, chewy, and juicy" texture, increasing yield by at least 15%. The components of the preservation adhesive work synergistically to construct a "dynamic preservation system," comprehensively ensuring quality stability from marinating to the finished product. Preferably, the cellulose derivative is calcium carboxymethyl cellulose.

[0026] By adopting the above technical solution, the selected and pre-treated duck gizzards are marinated through steps such as deodorizing pre-marinating, preservation coating, vacuum permeation marinating, maturation and sterilization. The preservation adhesive is obtained by diluting a preservation adhesive containing a specific weight ratio of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan in water at a weight ratio of 1:10. Among them, the cellulose derivative is calcium carboxymethyl cellulose, which can achieve efficient stepwise deodorization and targeted retention of flavor substances, making the finished product full-bodied and with a strong sense of layering. It synergistically optimizes the texture and yield, forming a crisp, chewy, and juicy texture, and improving the yield. The components of the preservation adhesive work synergistically to ensure quality stability from three dimensions: physical barrier, moisture retention, and microbial inhibition. Finally, a high-preservation marinated duck gizzard product with full flavor, superior taste, and stable quality is obtained.

[0027] Preferably, the weight ratio of the preservative adhesive to water is 1:10.

[0028] By adopting the above technical solutions, combining screening and pretreatment, deodorizing pre-marinating, preservation coating, vacuum penetration marinating, maturation and sterilization, and a preservation adhesive composed of water-soluble mussel adhesive protein, honey extract, cellulose derivatives and carboxymethyl chitosan, the preservation adhesive is mixed with water at a weight ratio of 1:10 to obtain a preservation solution. This ensures that the preservation solution has a suitable concentration and performance, and better forms a dense protective film with water retention and antibacterial functions on the surface of the duck gizzard. In synergy with other marinating steps, it effectively removes the fishy smell of the duck gizzard, retains the internal flavor substances, optimizes the texture and yield of the duck gizzard, and comprehensively ensures the quality stability of the duck gizzard from marinating to the finished product.

[0029] In summary, this application includes at least one of the following beneficial technical effects: 1. Through a three-step process of "pre-marinating to remove fishy smell → preservative coating → vacuum penetration marinating", most of the fishy smell substances on the surface and shallow layer of duck gizzard are effectively removed. At the same time, the protective film formed by the preservative coating can prevent the precious water-soluble flavor substances inside the duck gizzard from diffusing back into the marinade, thus enhancing the fullness and layering of the finished product's flavor. 2. The water-soluble mussel adhesive protein, honey extract, cellulose derivatives, and carboxymethyl chitosan in the preservative solution are combined to form a composite film on the surface of the duck gizzard. Combined with the vacuum permeation marinating process, it achieves "only flavor in, little water out", allowing the myofibrils to fully swell without excessive loss, resulting in a "crisp and chewy, juicy inside" texture. 3. The specially formulated preservative solution utilizes the synergistic effect of its components: water-soluble mussel adhesive protein ensures complete protective film coverage, honey extract enhances water retention, cellulose derivatives provide mechanical strength, and carboxymethyl chitosan imparts antibacterial properties. Together with the low-temperature pickling process, these components inhibit microbial growth and extend shelf life. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the embodiments.

[0031] Sources of some raw materials: Water-soluble mussel adhesive protein, CAS No. 3047117-55-2; Honey extract CAS number 91052-92-5; The cellulose derivative is calcium carboxymethyl cellulose, CAS No.: 9050-04-8 Carboxymethyl chitosan CAS No.: 83512-85-0; Soy protein isolate CAS number: 9010-10-0; Disodium inosinate CAS No.: 12111-11-4; MSG CAS No.: 32221-81-1; The deodorizing powder contains caramel ethyl maltol, brand name Jijie, with an effective ingredient content of 99%. Ethyl maltol CAS No.: 4940-11-8; Red yeast rice is red; The brand of oil-soluble capsicum extract is Shenghe Chemical, model XH5280L7SLAY; Spicy compound oil is made by mixing rapeseed oil, peanut oil, chili powder, Sichuan pepper powder, and white pepper powder in a weight ratio of 6:3:0.5:0.3:0.2, heating and sautéing the mixture until fragrant, and then cooling it. Example

[0032] Example 1 A high-preservation marinating method for duck gizzards is obtained through the following method: Preparation of the pickling liquid: Weigh out 0.2 kg of water-retaining agent (soy protein isolate) and 0.075 kg of edible salt according to weight (kg), dissolve them in 1 kg of water, add all the flavoring agents, mix well, then add all the deodorizing and preservative agents and mix well to obtain the pickling liquid.

[0033] The preservative adhesive solution is obtained by diluting 1 kg of preservative adhesive in 10 kg of water (make sure it is thoroughly mixed and the solid particles are completely dissolved).

[0034] The preservative adhesive is composed of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan in a weight ratio of 1:1:2.5:0.5. The cellulose derivative is calcium carboxymethyl cellulose.

[0035] Screening and pretreatment: Select fresh duck gizzards, manually remove the fascia, blood vessels and residual impurities on the surface of the duck gizzards, rinse with clean water 3 times to remove surface blood, and then put them in a draining basket to drain, controlling the surface moisture content ≤15% to avoid dilution of the subsequent marinade concentration, to obtain duck gizzard A; Pre-marinating to remove fishy smell: Put 5kg of duck gizzard A and all the marinade into a tumbler and knead for 3 minutes at a speed of 10r / min. After removing the duck gizzards, let them air dry naturally until the surface moisture content is 25% to obtain duck gizzard B. Preservative Coating: Spread all duck gizzards B evenly on a conveyor belt, and spray both sides of the duck gizzard surface with a colloid spraying device. The spraying amount is controlled at 5g of preservative adhesive per 100g of duck gizzard. After spraying, let it stand for 5 minutes to allow the preservative adhesive to form a uniform and airtight protective film on the surface of the duck gizzard. This film can prevent water-soluble proteins such as sarcoplasmic proteins from seeping out. Spray the surface of duck gizzard B with preservative glue solution on both sides, and air dry at 30℃ and 50% humidity (until the surface is dry, and its surface moisture content is about 10%) to obtain duck gizzard C. Vacuum permeation marinating: Place the duck gizzards C back into the tumbler, start the equipment to vacuum to the set pressure of 0.06MPa, then tumble and stir for 10 minutes at a speed of 5r / min, then let stand for 30 minutes, then tumble for another 30 minutes and repeat the operation twice. Then pour the duck gizzards from the tumbler into a special frame according to the weight requirements and marinate at -2℃ for 3 hours to ensure that the marinade penetrates evenly and to avoid damage to the duck gizzard cells due to pressure changes, thus obtaining duck gizzard D.

[0036] Cooking and sterilization: Mix all the duck gizzards D with 0.015kg of braising essence evenly and put them into a steam jacketed kettle for cooking (first heat at 100℃ for 15 minutes to quickly set the surface of the duck gizzards and initially absorb the flavor of the essence; then adjust to 90℃ for constant temperature cooking for 25 minutes). After cooking, quickly transfer them to a vacuum cooling machine and set the cooling temperature to 4℃ to quickly reduce the core temperature of the duck gizzards from 90℃ to below 10℃. Then add all the coloring agent and all the seasoning agent and mix them evenly with the cooled duck gizzards to evenly cover the surface of the duck gizzards. After coloring and seasoning, put the duck gizzards into a high-temperature sterilizer and set the temperature to 121℃, the pressure to 0.15MPa, and the sterilization time to 10 seconds to obtain highly fresh marinated duck gizzards.

[0037] The flavoring agent consists of 0.2 kg of white sugar, 0.1 kg of monosodium glutamate, and 0.01 kg of disodium nucleotides. The deodorizing and preservative agent consists of 0.04 kg of liquor, 0.015 kg of ginger powder, 0.03 kg of deodorizing powder, and 0.01 kg of ethyl maltol. The seasoning consists of 0.015 kg of oil-soluble chili oil and 0.15 kg of spicy compound oil; The colorant consists of 0.005 kg of red yeast rice and 0.010 kg of red chili peppers.

[0038] Example 2 The difference between Example 2 and Example 1 lies in the process parameters, as detailed below: In the pre-marinating process to remove fishy smell, knead and mix for 4 minutes; in the vacuum penetration marinating process, marinate at 1℃ for 2.5 hours; spray 6g of preservative liquid on every 100g of duck gizzards.

[0039] Example 3 The difference between Example 3 and Example 1 lies in the process parameters, as detailed below: In the pre-marinating process to remove fishy smell, knead and mix for 5 minutes; in the vacuum penetration marinating process, marinate at 2℃ for 4 hours; spray 8g of preservative liquid on every 100g of duck gizzards.

[0040] Example 4 The difference between Example 4 and Example 1 is that the weight ratio of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan is 1:2:3:0.6.

[0041] Example 5 The difference between Example 5 and Example 1 is that the weight ratio of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan is 1:3:5:0.5.

[0042] Comparative Example

[0043] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that water-soluble mussel adhesive protein was replaced with an equal amount of honey extract.

[0044] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the honey extract was replaced with an equal amount of water-soluble mussel adhesive protein.

[0045] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the cellulose derivative and carboxymethyl chitosan were replaced with honey extract in equal amounts.

[0046] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that step 2 (pre-marinating to remove fishy smell) is omitted; the duck gizzard A is directly coated with a preservative coating.

[0047] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that step 3 (preservative coating) is omitted; the duck gizzards B are directly vacuum-infused and marinated.

[0048] Experimental methods

[0049] I. Texture and Taste Testing Texture analysis (TPA) was used. Instrument: Texture analyzer (TA-XTPlus), P / 50 cylindrical probe.

[0050] Samples: High-preservation marinated duck gizzards obtained from Examples 1-5 and Comparative Examples 1-5.

[0051] Parameters: Test speed 2mm / s, compression ratio 50%, interval time 5s.

[0052] Indicators: hardness, elasticity, shear force.

[0053] Operating steps: Cut the sample into 1cm³ cubes, compress at a speed of 1mm / s, and compress at a rate of 50%. When the hardness is 500-1000g, the shear force is 1.8-2.3kg·f, and the elasticity is ≥0.85, it is considered that the texture and taste are qualified. If any one of the hardness, elasticity, or shear force fails to meet the above standards, it is considered that the texture and taste are unqualified.

[0054] II. Food Safety 2-1. Total bacterial count determination: According to GB4789.2-2022, the plate counting method is adopted.

[0055] Operating procedure: Take 25g of high-preservation marinated duck gizzards, add 225mL of sterile physiological saline to homogenize, dilute to the appropriate concentration, take 1mL and spread it on a plate, incubate at 37℃ for 48h, and count the number of colonies.

[0056] Results analysis: Total bacterial count ≤10 4 A CFU / g level is considered acceptable, reflecting the inhibitory effect of the pickling process on microorganisms.

[0057] 2-2 Detection of pathogenic bacteria (Salmonella, Staphylococcus aureus): Salmonella: According to GB4789.4-2016, the three-stage enrichment method is used.

[0058] Staphylococcus aureus: The Baird-Parker plate method was used according to GB4789.10-2016.

[0059] Results analysis: The absence of pathogenic bacteria (Salmonella and Staphylococcus aureus) indicates that the product is qualified, ensuring product safety.

[0060] When both 2-1 and 2-2 above are qualified, it is recorded as food safety qualified.

[0061] III. Detection of Umami Retention Rate Samples: Duck gizzard A (blank), duck gizzard D obtained from Examples 1-5 and Comparative Examples 1-5.

[0062] Pretreatment: After homogenization, precipitate the protein with 5% TCA, centrifuge and collect the supernatant.

[0063] Detection: High performance liquid chromatography (HPLC) was used, according to GB / T20374-2006; 3-1. Free amino acids: The total amount of 16 amino acids was determined using an amino acid analyzer (ninhydrin method).

[0064] 3-2. Flavor nucleotides: IMP and GMP content determined by HPLC.

[0065] Calculation: Retention rate = (Content after marinating (Duck gizzard D) / Content of fresh sample (Duck gizzard A)) × 100%.

[0066] The retention rates of umami substances are as follows: Grade A: ≥93%; Grade B: 90% ≤ B < 93%; Grade C: 85% ≤ B < 90%; Grade D: 80% ≤ B < 85%; Grade E: ≤80%.

[0067] 3-3, Water retention rate Samples: Duck gizzard A (blank), and high-preservation marinated duck gizzards obtained from Examples 1-5 and Comparative Examples 1-5.

[0068] Sampling rules: For each sample group (duck gizzard A, Examples 1-5, Comparative Examples 1-3), the "random multi-point sampling method" was used. Three whole duck gizzards were randomly selected from the same batch of samples. The broth and seasoning particles attached to the surface of each duck gizzard were removed (they were gently wiped with sterile absorbent paper to avoid squeezing and causing moisture loss). Then, each duck gizzard was cut into four equal parts along the length. About 10g of meat was randomly selected from each part (avoiding areas with dense tendons and membranes to ensure sample homogeneity) to form three parallel samples of the sample group. The mass of each parallel sample was controlled at (10.00±0.02)g.

[0069] Moisture content test: Take a pre-weighed stainless steel sample pan (mass m0), place the pretreated duck gizzard sample (parallel sample) into the pan, and weigh the total mass of the sample and sample pan using an analytical balance, recording it as "m1" accurate to 0.0001g. Place the sample pan containing the sample into an electrically heated constant temperature drying oven preheated to 105℃, open the ventilation valve to allow the humidity inside the oven to be evenly discharged, close the oven door, and maintain a constant temperature of 105℃ for drying for 4 hours. After drying, remove the sample pan with sterile crucible tongs, quickly place it into a glass desiccator, tighten the lid, and cool to room temperature (approximately 30 minutes, to avoid excessive cooling time causing the sample to absorb moisture). Then, weigh the total mass of the sample pan and the dried sample using an analytical balance, recording it as "m2".

[0070] The moisture content (w) of each sample group is calculated using the following formula, with the result rounded to two decimal places: w = (m1-m2) / (m1-m0) × 100% Water retention rate (R): Calculation method: Based on the moisture content of the blank group (duck gizzard A), the water retention rate (R) of Examples 1-5 and Comparative Examples 1-3 is calculated to reflect the process's ability to retain moisture in duck gizzards. The result is rounded to one decimal place: R = (wsample / wblank) × 100%. A water retention rate greater than 90% is considered qualified, otherwise it is unqualified.

[0071] IV. Sensory Evaluation Samples: High-preservation marinated duck gizzards obtained from Examples 1-5 and Comparative Examples 1-5.

[0072] A sensory evaluation panel of 10 people (half male and half female, aged 18-40) was formed to score the samples based on four dimensions: color, smell, taste, and flavor (1-9 points).

[0073] Results analysis: Calculate the average total score. Those with an average total score ≥ 35 are considered to have passed the sensory evaluation.

[0074] The specific experimental data are shown in Table 1. Table 1. Experimental data of Examples 1-5 and Comparative Examples 1-5

[0075] Based on Example 1 and Comparative Examples 1-3 and Table 1, it can be seen that the umami retention rate (C / D) of Comparative Examples 1-3 is lower than that of Example 1 (B). Comparative Examples 1 and 3 both show unqualified sensory properties and water retention rate. Comparative Examples 1-3 also show unqualified texture and taste. However, Example 1 is qualified in all aspects. Therefore, it can be concluded that the preservative adhesive of this application, which consists of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan, has a synergistic effect and further improves the overall performance of duck gizzard after marinating.

[0076] Comparing Example 1 and Comparative Example 4 with Table 1, it can be seen that Comparative Example 4 omits step 2 (pre-marinating to remove fishy smell); the duck gizzard A is directly coated for preservation, resulting in substandard sensory qualities, texture, and taste. Furthermore, the umami retention rate is consistent with that of Example 1. This indicates that the pre-marinating process for removing fishy smell in this application not only removes fishy smell and improves taste, but also minimizes the loss of umami substances due to the glue, the emulsification and water retention effects of soy protein isolate in the marinade, and the activation effect on the duck gizzard during the pre-marinating process, thus facilitating subsequent preservation coating.

[0077] Comparing Example 1 and Comparative Example 5, it can be seen that the umami retention rate (E) of Comparative Example 5 is lower than that of Example 1. The sensory properties, water retention, texture and taste of Comparative Example 1 and Comparative Example 3 are all unqualified. This shows that the use of the preservation coating process in step 3 of this application in combination with the preservation adhesive of this application has a better effect and further improves the overall performance of the duck gizzard after marinating.

[0078] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for highly preserving the freshness of duck gizzards through marinating, characterized in that, Obtained by the following method: Screening and pretreatment: After screening and pretreatment, the duck gizzards are drained to obtain duck gizzard A; Pre-marinating to remove fishy smell: Mix duck gizzard A with the marinade for 3-5 minutes, then remove and dry until the surface moisture content is less than 30% to obtain duck gizzard B; Preservative coating: Apply a preservative adhesive to both sides of the surface of duck gizzard B, and let it dry to obtain duck gizzard C; Vacuum permeation marinating: Duck gizzard C is put back into the marinating liquid and tumbled and stirred at least once under vacuum. The tumbling and stirring process includes tumbling under vacuum for at least 10 minutes, then standing for at least 30 minutes, and then marinating at -2~2℃ for 2.5-4 hours to obtain duck gizzard D; Cooking and sterilization: Mix duck gizzards with braising spices and cook. After cooking, cool, add coloring agents and seasonings and mix evenly. Sterilize to obtain highly fresh marinated duck gizzards. The preservative adhesive solution is obtained by diluting a preservative adhesive in water. The preservative adhesive is composed of water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan.

2. The high-preservation marinating method for duck gizzards according to claim 1, characterized in that, The pickling solution is obtained by the following method: Weigh out the water-retaining agent and edible salt, dissolve them in water, add the flavoring agent, mix well, then add the deodorizing and preservative agent and mix well to obtain the pickling liquid.

3. The high-preservation marinating method for duck gizzards according to claim 1, characterized in that: The amount of coating is controlled to be 5-8g of preservative adhesive per 100g of duck gizzard.

4. The high-preservation marinating method for duck gizzards according to claim 1, characterized in that: The flavoring agent is one or more of the following: white sugar, monosodium glutamate, and disodium inosinate.

5. A high-preservation marinating method for duck gizzards according to claim 1, characterized in that: The deodorizing and preservative agent is a combination of one or more of the following: liquor, ginger powder, deodorizing powder, and ethyl maltol.

6. A high-preservation marinating method for duck gizzards according to claim 1, characterized in that: The colorant is red yeast rice and / or red chili pepper.

7. A high-preservation marinating method for duck gizzards according to claim 1, characterized in that... The seasoning is oil-soluble chili oil and / or spicy compound oil.

8. A method for high-preservation marinating of duck gizzards according to any one of claims 1-7, characterized in that: The weight ratio of the water-soluble mussel adhesive protein, honey extract, cellulose derivative, and carboxymethyl chitosan is 1:(1-3):(2.5-5):(0.5-1).

9. A high-preservation marinating method for duck gizzards according to claim 8, characterized in that: The cellulose derivative is calcium carboxymethyl cellulose.

10. A high-preservation marinating method for duck gizzards according to claim 1, characterized in that: The weight ratio of the preservative adhesive to water is 1:10.

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