Preparation method of compound sausage of antarctic krill, tuna and collagen

Abstract

This invention belongs to the field of functional marine food processing technology, specifically involving a method for producing a composite sausage made from Antarctic krill, tuna, and collagen, comprising the following steps: (1) preparation of Antarctic krill meat, (2) preparation of tuna blood-infused meat, (3) preparation of low-temperature raw pork skin collagen paste, (4) preparation of krill-derived composite enzyme solution, (5) mixing of meat materials and low-temperature enzymatic hydrolysis, (6) low-temperature chopping, (7) sausage filling and quick-freezing, and (8) thawing and maturation of the product. This invention uses Antarctic krill meat, tuna blood-infused meat, and low-temperature raw pork skin collagen paste as core raw materials, and utilizes krill endogenous composite enzymes for low-temperature enzymatic hydrolysis to produce a composite sausage with uric acid-lowering function, high protein content, and high unsaturated fatty acid content, providing a safe, convenient, and daily-consumable functional marine food for people with hyperuricemia.

Description

Technical Field

[0001] This invention belongs to the field of functional marine food processing technology, specifically relating to a method for producing a composite sausage made from Antarctic krill, tuna, and collagen. Background Technology

[0002] Hyperuricemia is a metabolic disease caused by abnormal purine metabolism or insufficient uric acid excretion, mainly manifested as abnormally elevated serum uric acid levels. Currently used uric acid-lowering drugs such as allopurinol and febuxostat, while possessing strong anti-hyperuricemia activity, can cause adverse reactions such as allergies. Therefore, developing safe and effective natural functional foods to help alleviate hyperuricemia is of significant practical importance.

[0003] Antarctic krill (Euphausia superba) is rich in high-quality protein and a variety of unsaturated fatty acids, containing all the essential amino acids for the human body, making it a marine protein resource with great development potential. Current technologies utilize Antarctic krill to prepare uric acid-lowering products; however, these products are mainly small molecule peptides separated and purified after enzymatic hydrolysis, resulting in a limited product form. Tuna blood-infused meat (dark meat) refers to the dark reddish edge of the tuna flesh, and its nutritional value is higher than that of ordinary white meat. However, this dark meat contains a large amount of hemoglobin, and the heme and non-heme iron in hemoglobin promote lipid oxidation. During processing into meat products, this easily leads to discoloration, flavor degradation, and quality decline. Due to its strong fishy smell, blood-infused meat is currently mainly used for processing fishmeal feed, with its edible development and utilization severely insufficient. Pig skin is inexpensive, readily available, and rich in collagen, making it a high-quality edible collagen source. However, traditional pigskin collagen processing mostly uses acid or alkali extraction methods, which require a large amount of chemical reagents. Moreover, the extracted collagen is mostly added in the form of functional ingredients, but there are few existing technologies that use it directly as one of the main meat ingredients in the production of processed sausages.

[0004] Therefore, it is of great significance to develop a functional compound conditioning sausage with uric acid-lowering function, high protein content, and high unsaturated fatty acid content, using Antarctic krill meat, tuna blood-infused meat, and low-temperature raw pork skin paste as core raw materials. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for making a composite sausage made of Antarctic krill, tuna, and collagen.

[0006] A method for preparing a composite sausage made from Antarctic krill, tuna, and collagen includes the following steps: (1) Thaw the frozen Antarctic krill raw material at low temperature, and control the thawing temperature to not exceed 60°C. After thawing, remove the shell and collect the Antarctic krill meat. At the same time, collect the by-products. Store the shelled Antarctic krill meat at ultra-low temperature. As a preferred technical solution of the present invention, the thawing in step (1) includes microwave thawing, radio frequency thawing or low temperature running water thawing. The power of microwave thawing is 200-500W / kg, the frequency is 915MHz or 2450MHz, the thawing time is 5-20min, the shrimp body temperature is controlled at 40-55℃, and the enzyme activity is reduced by 40-60%.

[0007] In the above process, microwave thawing is used. When microwaves penetrate the frozen krill, water molecules rotate at high speed in an alternating electric field, generating heat through friction and achieving uniform thawing from the inside out. Simultaneously, the thermal and non-thermal effects of microwaves synergistically act on the cryogenic enzyme system within the Antarctic krill (mainly including trypsin, carboxypeptidase, and lipase), causing partial conformational changes in the enzyme proteins and achieving partial inactivation. Compared to natural thawing, this step can reduce enzyme activity by 40-60%, effectively minimizing protein loss due to enzymatic degradation during thawing and subsequent shelling.

[0008] (2) The tuna preserved at ultra-low temperature is cut and the blood-infused meat is removed under low temperature conditions of 0-4℃. During the cutting process, protective gas is used to protect the operation environment and the oxygen concentration is controlled to be below 1 vol%. After cutting, the blood-infused meat is minced into tuna blood-infused meat paste. As a preferred technical solution of the present invention, the protective gas in step (2) is argon, nitrogen or a mixture of nitrogen gas with an integral of 80-95% and carbon dioxide volume fraction of 5-20%; the protein content of the tuna blood meat is 75-81% dry basis, and the unsaturated fatty acid content accounts for 37-58% of the total fat.

[0009] In the above process, nitrogen is used as a protective gas to fix the color of the blood-soaked meat of red fish such as tuna. The principle is to inhibit the oxidation of myoglobin, the pigment in the red fish muscle. The extracted blood-soaked meat contains 75-81% protein (dry basis) and 37-58% unsaturated fatty acids, making it highly nutritious.

[0010] (3) Using defatted pig back skin as raw material, the pig skin is subjected to low-temperature crushing, low-temperature mud stirring, low-temperature acid emulsification and low-temperature mechanical micro-grinding in sequence at 0-10℃ to obtain low-temperature raw pig skin collagen paste. As a preferred technical solution of the present invention, the particle size of the material crushed at low temperature in step (3) is 2-5 mm, the low temperature acid emulsification is carried out by organic acid, the organic acid is food grade lactic acid, citric acid, malic acid or tartaric acid, the amount added is 0.5-2.0% of the mass of pig skin paste, the emulsification pH value is 5.0-6.0, the particle size of the material after low temperature mechanical micro-grinding is 50-200 μm; the protein content of the obtained low temperature raw pig skin collagen paste is ≥80% dry basis.

[0011] During the above operations, the material temperature is strictly controlled below 20℃ throughout the entire pigskin processing process to ensure the raw material condition, avoid collagen denaturation and microbial growth caused by high temperatures, and preserve the natural structure and gel-forming ability of pigskin collagen. No acid- or alkali chemical extraction is used during processing, achieving low-temperature physical processing of pigskin collagen.

[0012] (4) Grind the by-products collected in step (1) into shrimp head paste, add 4℃ low temperature reverse osmosis water for low temperature extraction, and obtain krill source complex enzyme solution by centrifugation; As a preferred technical solution of the present invention, the low temperature extraction temperature in step (4) is 4-10℃, the extraction time is 2-6h, the mass ratio of low temperature reverse osmosis water to shrimp head mud is 2:1-5:1, and the centrifugation conditions are 4℃, 3000-5000rpm for 10-20min; the krill source complex enzyme solution contains trypsin, chymotrypsin and carboxypeptidase.

[0013] In the above process, the highly active autolytic enzyme system within Antarctic krill is utilized to fully dissolve the endogenous proteases in the krill head through a low-temperature extraction method. During the extraction process, low-temperature reverse osmosis water effectively avoids the inhibition of enzyme activity by chloride ions and other contaminants in tap water, while also reducing bacterial contamination.

[0014] (5) Mix the Antarctic krill meat from step (1), the tuna blood-infused minced meat from step (2), the low-temperature raw pork skin collagen minced meat from step (3), and the krill-derived complex enzyme solution from step (4). Add ice water, salt, compound phosphate and spices, and carry out low-temperature enzymatic hydrolysis reaction at 10-25℃ for 8-16 hours. As a preferred technical solution of the present invention, the weight parts of each raw material in step (5) are as follows: 20-40 parts of Antarctic krill meat, 15-35 parts of tuna blood-infused minced meat, 20-40 parts of low-temperature raw pork skin collagen minced meat, 5-15 parts of krill-derived compound enzyme solution, 5-15 parts of ice water, 0.5-2.0 parts of salt, 0.1-0.5 parts of compound phosphate, and 0.5-2.0 parts of spices.

[0015] As a preferred technical solution of the present invention, exogenous alkaline protease or flavor protease is added in step (5).

[0016] During the above process, various endogenous proteases (trypsin, chymotrypsin, carboxypeptidase, etc.) in the krill-derived complex enzyme solution undergo moderate and limited hydrolysis of large-molecule proteins in the mixed meat under low-temperature conditions. This degrades some proteins into small-molecule peptides and free amino acids, while simultaneously releasing functional peptide components with uric acid-lowering activity. The low-temperature enzymatic hydrolysis conditions ensure the controllability of the process, avoiding the production of bitter peptides and textural degradation caused by excessive hydrolysis. Collagen in the pig skin collagen paste is partially degraded into collagen peptides during enzymatic hydrolysis, further enhancing the product's functionality and digestibility. Antarctic krill peptides exhibit significant XOD inhibitory activity, effectively reducing uric acid content. Through this low-temperature enzymatic hydrolysis step, small-molecule peptides with uric acid-lowering activity are generated in situ in the mixed meat, achieving the "endogenous" preparation of functional components without the need for externally purified peptide products, thus reducing production costs.

[0017] (6) The enzymatically hydrolyzed material is chopped at low temperature to obtain meat paste. During the chopping process, the material temperature is kept below 12°C. As a preferred technical solution of the present invention, the low-temperature chopping in step (6) includes low-speed chopping and high-speed chopping. The conditions for low-speed chopping are 500-1000 rpm for 3-5 min, and the conditions for high-speed chopping are 2000-3000 rpm for 2-4 min. During the chopping process, ice water is added in batches to keep the material temperature not exceeding 12°C.

[0018] The meat paste obtained by the above-mentioned low-temperature chopping is a uniform, delicate, and viscous paste with a uniform color and good viscoelasticity and water retention.

[0019] (7) The chopped meat paste is stuffed into sausage casings and then quick-frozen to produce frozen prepared composite meat sausages; As a preferred technical solution of the present invention, the quick-freezing process in step (7) includes tunnel quick-freezing, liquid nitrogen quick-freezing or plate quick-freezing.

[0020] During the above operation, the product is quickly passed through the maximum ice crystal formation zone (-1 to -5°C) to minimize the damage of ice crystals to the microstructure of the meat and maximize the preservation of the product's textural properties and the activity of its functional components. The quick-frozen product can be stored at temperatures below -18°C for 6 to 12 months.

[0021] (8) The composite sausage is thawed and cooked to obtain a composite sausage with uric acid reduction function. The composite sausage reduces serum uric acid level by 20-50%.

[0022] As a preferred technical solution of the present invention, the method of cooking the compound sausage in step (8) includes roasting, frying or steaming; the protein content of the cooked compound sausage is ≥20% wet basis or ≥60% dry basis, and the unsaturated fatty acid content accounts for more than 40% of the total fatty acid content.

[0023] The composite sausage prepared by this invention can significantly reduce serum uric acid levels in mice with hyperuricemia induced by a high-purine diet, with a reduction of 20-50% (in a dose-dependent manner); at the same time, it can significantly inhibit liver XOD activity, reduce serum creatinine and urea nitrogen levels, and has a protective effect on kidney function.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention is the first to integrate uric acid-lowering function with the preparation of a compound conditioning sausage. It organically combines the in-situ generation of Antarctic krill peptides with uric acid-lowering activity with the preparation process of the compound conditioning sausage. Through low-temperature enzymatic hydrolysis of the krill-derived compound enzyme solution, active peptide components with uric acid-lowering function are generated inside the sausage without the need for external purification of peptide products. Animal experiments have confirmed that the cooked compound sausage can significantly reduce serum uric acid levels in mice with high-purine diet-induced hyperuricemia by 20-50%, while inhibiting liver XOD activity and protecting kidney function. This provides a safe, convenient, and daily-consumable functional marine food for people with hyperuricemia.

[0025] (2) Low-temperature processing throughout the entire process maximizes the preservation of nutrients and bioactivity. From microwave thawing of Antarctic krill (≤60℃), low-temperature cutting of tuna blood-infused meat (0~4℃), low-temperature processing of pork skin collagen (≤20℃), low-temperature extraction of krill enzymes (4~10℃), low-temperature enzymatic hydrolysis of meat (10~25℃), to low-temperature chopping (≤12℃) and quick-freezing, the material temperature is controlled below 60℃ throughout the entire processing, with key steps controlled below 20℃. This low-temperature control effectively avoids protein denaturation, unsaturated fatty acid oxidation, and degradation of active substances, maximizing the preservation of the natural nutritional and functional properties of Antarctic krill, tuna blood-infused meat, and pork skin collagen.

[0026] (3) Scientific blending of multiple protein sources for comprehensive optimization of nutritional structure. This invention scientifically blends three high-quality protein sources: Antarctic krill meat (rich in ω-3 polyunsaturated fatty acids and astaxanthin), tuna blood-infused meat (high in protein, iron, and unsaturated fatty acids), and low-temperature raw pork skin collagen paste (rich in collagen and characteristic amino acids such as glycine and proline), forming a ternary protein combination of "marine animal protein + marine red-fleshed fish protein + terrestrial collagen". The resulting composite sausage has a high protein content (≥20%, on a wet basis), is rich in unsaturated fatty acids, has a balanced amino acid composition, and combines the gel-forming properties of animal muscle protein with the elastic texture of collagen. Its nutritional value and edible quality are significantly superior to traditional single-protein source sausages.

[0027] (4) High-value utilization of krill by-products to achieve "endogenous preparation" of compound enzyme solution. This invention innovatively utilizes Antarctic krill molting by-products (krill heads, etc.) to extract krill-derived compound enzyme solution at low temperature for subsequent low-temperature enzymatic hydrolysis and conditioning of mixed meat. Krill contains eight endogenous proteases with extremely high autolytic activity. The compound enzyme solution obtained by low-temperature reverse osmosis water extraction is rich in various active enzymes such as trypsin, chymotrypsin, and carboxypeptidase, eliminating the need to purchase commercial proteases and achieving "endogenous" preparation of the hydrolysate, significantly reducing production costs, and simultaneously realizing the high-value utilization of krill processing by-products.

[0028] (5) Nitrogen-protected processing of tuna blood-infused meat, breaking through the bottleneck of dark meat utilization. This invention uses a low-temperature segmentation process under nitrogen protection to process tuna blood-infused meat, controlling the oxygen concentration in the processing environment to below 1 vol%, effectively inhibiting the oxidation and ferritinization of myoglobin, and maintaining the natural color of the blood-infused meat. The blood-infused meat is directly applied to composite sausages in the form of low-temperature minced meat, overcoming the technical bottleneck of traditional processing where tuna blood-infused meat is difficult to eat due to its dark color, strong fishy smell, and easy oxidation, thus realizing the high-quality edible development of tuna blood-infused meat. Based on constant weight after drying, the protein content of the blood-infused meat is 75-81%, and the unsaturated fatty acid content accounts for 37-58% of the total fat, significantly improving the nutritional value of composite sausages.

[0029] (6) Low-temperature raw processing of pigskin collagen, achieving green processing through physical methods. This invention employs a four-step physical process—low-temperature crushing, low-temperature mixing, low-temperature acid emulsification, and low-temperature micro-grinding—to prepare pigskin collagen paste. The material temperature is controlled below 20°C throughout the process, and no acid-base chemical extraction is used, thus achieving green raw processing of pigskin collagen. The resulting pigskin collagen paste has a delicate texture and good water retention. During the low-temperature chopping process, it synergistically forms a dense and uniform gel network with myofibril protein, giving the composite sausage excellent elasticity, chewiness, and slicing properties. At the same time, characteristic amino acids such as glycine, proline, and hydroxyproline in pigskin collagen are released after enzymatic hydrolysis, further enriching the product's functionality.

[0030] (7) Low-temperature enzymatic hydrolysis generates uric acid-lowering active peptides in situ, achieving "endogenous" functional factors. This invention utilizes a krill-derived compound enzyme solution to perform an enzymatic hydrolysis reaction on mixed meat materials at a low temperature of 10-25℃ for 8-16 hours, moderately hydrolyzing the large molecular proteins in the raw materials into small molecular peptides and free amino acids. Studies have shown that Antarctic krill peptides have significant XOD inhibitory activity, significant uric acid-lowering function, and can regulate the expression of renal uric acid transport proteins and promote uric acid excretion. Through the low-temperature enzymatic hydrolysis process of this invention, functional peptide components with uric acid-lowering activity are generated in situ inside the sausage, avoiding the complex process of "enzymatic hydrolysis, separation and purification, and then addition" in traditional enzymatic hydrolysis processes, and achieving efficient "endogenous" functional factors.

[0031] (8) The product has excellent nutritional indicators and meets the trend of healthy consumption. The main nutritional indicators of the compound seasoned sausage (after roasting) prepared by this invention are as follows: protein content ≥20% (wet basis) or ≥60% (dry basis), unsaturated fatty acid content as a percentage of total fatty acid content ≥40%, collagen content ≥5%, and astaxanthin content ≥5mg / 100g. The product is low in fat and salt (sodium content ≤500mg / 100g), and does not contain artificial preservatives or pigments, meeting the needs of modern consumers for healthy, nutritious, and functional foods.

[0032] (9) The process is highly operable and suitable for industrial production. The parameters of each process step in this invention are clear, the equipment is universal, and the operation is controllable. It can be scaled up based on existing meat processing production lines. The frozen prepared product form is convenient for storage, transportation, and sales. End consumers only need to cook it simply before eating, which has broad market prospects. Detailed Implementation

[0033] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention. Example

[0034] This embodiment provides a method for preparing a composite sausage made from Antarctic krill, tuna, and collagen, including the following steps: (I) Preparation of Antarctic krill meat Take 50 kg of whole frozen Antarctic krill with a core temperature of -22°C. Place them in a microwave defrosting device with a microwave frequency of 915 MHz and a power of 350 W / kg. During the defrosting process, monitor the surface temperature of the shrimp in real time using an infrared thermometer, controlling the maximum temperature to not exceed 55°C. Defrost for 12 minutes, until the shrimp are completely thawed, soft to the touch, and free of ice crystals.

[0035] The total protease activity of shrimp samples before and after thawing was measured. The results showed that the total protease activity of shrimp after microwave thawing decreased by about 48% compared with that before thawing, which effectively achieved partial inactivation of the enzyme.

[0036] After thawing, the Antarctic krill were mechanically deshelled, and about 21 kg of deshelled Antarctic krill meat was collected; at the same time, about 9 kg of by-products such as shrimp heads were collected for the preparation of compound enzyme solution.

[0037] (II) Preparation of Tuna Blood-Meat Approximately 30 kg of tuna raw material, cryopreserved at -58℃, was taken out in a clean, low-temperature operating room at 2℃. About 8 kg of the blood-infused meat was then removed using a cryogenic cutting knife. Throughout the cutting process, the operating area and the surface of the fish meat were continuously purged with pure nitrogen (purity ≥99.9%) for protection, and the oxygen concentration inside the operating chamber was controlled below 0.8 vol%. The extracted blood-infused meat was a bright, dark red color with no obvious browning.

[0038] The blood-infused meat was ground into minced meat at 2°C using a meat grinder. The minced meat was then tested and found to contain 78.5% protein (dry basis), 9.2% fat (dry basis), and 52.3% unsaturated fatty acids.

[0039] (III) Preparation of Low-Temperature Raw Pigskin Collagen Paste Take 10 kg of carefully selected defatted pig back skin, wash it with clean water and scrape off the remaining fat. Soak it in food-grade sodium hypochlorite solution (effective chlorine concentration 50 ppm) for 5 minutes for disinfection, then rinse with clean water and drain.

[0040] At 4°C, pig back skin was crushed into pieces with a particle size of approximately 3mm using a crusher. The pieces were then added to a chopper and chopped at low speed for 5 minutes at 4°C until a paste was formed. 100g of food-grade lactic acid (1% addition) was added to the pig skin paste, and the mixture was stirred and emulsified at 4°C for 20 minutes, adjusting the pH to 5.5. The emulsified material was then fed into a micro-milling device and micro-milled at 4°C for 15 minutes to obtain a low-temperature raw pig skin collagen paste with a particle size of approximately 100–150μm. The material temperature was controlled below 10°C throughout the entire process.

[0041] The following analysis was conducted on a sample of pigskin collagen chyme: protein content 81.6% (dry basis), fat content 15.2% (dry basis), and ash content 0.8%.

[0042] (iv) Preparation of krill-derived compound enzyme solution Take 9 kg of shrimp heads and other byproducts collected in step (I) and grind them into a paste using a meat grinder at 4℃. Add 27 L (3 times the volume) of 4℃ low-temperature reverse osmosis water, stir well, and extract at 6℃ for 4 hours. After extraction, centrifuge at 4℃ and 4000 rpm for 15 minutes using a plate centrifuge, and collect approximately 28.5 L of supernatant, which is the krill-derived complex enzyme solution.

[0043] Using casein as a substrate, enzyme activity was determined using the Folin-phenol method. The results showed that the total protease activity of the complex enzyme solution was 1560 U / mL (pH 7.5, 40℃). The complex enzyme solution was stored at 4℃ for later use.

[0044] (v) Meat mixture and low-temperature enzymatic hydrolysis Weigh each raw material according to the following proportions by weight: • Antarctic krill meat: 30 servings (15kg) • Tuna blood and minced meat: 25 servings (12.5kg) • Low-temperature raw pork skin collagen paste: 30 portions (15kg) • Krill-derived compound enzyme solution: 10 portions (5 kg) • Ice water (2℃): 5 portions (2.5kg) • Salt: 1.2 portions (0.6 kg) • Complex phosphate (sodium tripolyphosphate:sodium pyrophosphate = 1:1): 0.3 parts (0.15 kg) • Natural spices (mixed white pepper powder, ginger powder, and garlic powder): 1.0 part (0.5 kg) The above raw materials were mixed at low speed in a mixer for 8 minutes, with the material temperature controlled at 12℃. After being mixed evenly, the mixture was transferred to a jacketed cooling enzymatic hydrolysis reactor and subjected to enzymatic hydrolysis at 18℃ for 12 hours.

[0045] The degree of protein hydrolysis (DH%) was measured before and after enzymatic hydrolysis. The results showed that after 12 hours of enzymatic hydrolysis, the degree of hydrolysis increased from 0% to 8.6%, indicating that the protein underwent moderate limited hydrolysis.

[0046] (vi) Low-temperature chopping After the enzymatic hydrolysis reaction is complete, the material is transferred to a chopper. The first stage is low-speed chopping (800 rpm) for 4 minutes, with 1.5 kg of ice water added; the second stage is high-speed chopping (2500 rpm) for 3 minutes, with the remaining 1 kg of ice water added in two batches, keeping the material temperature below 10°C during the chopping process.

[0047] End point of chopping: The material is a uniform, fine, viscous emulsified meat paste with a uniform light pink color, good gloss, and viscoelasticity.

[0048] (vii) Enemas and quick-freezing The chopped meat paste is stuffed into 20mm diameter collagen casings using a sausage stuffer, and then tied into sections every 12cm, for a total of about 120 sausages. The temperature of the meat paste is maintained at 12℃ during the stuffing process.

[0049] The enema-filled product is immediately placed in a tunnel-type quick-freezing machine at a freezing temperature of -40℃ for 60 minutes, until the core temperature of the product reaches below -20℃. The quick-frozen product is then vacuum-packed and stored at -18℃.

[0050] (viii) Product indicator testing Three frozen sausages were thawed at 4°C for 3 hours, then baked at 180°C for 10 minutes until the center temperature reached 78°C. The baked products were then tested. Nutritional composition (per 100g of roasted product): Protein 23.5g, Fat 12.8g (of which 5.8g is unsaturated fatty acid, accounting for 45.3%), Carbohydrates 3.2g, Moisture 58.6g, Ash 2.0g, Sodium 356mg, Astaxanthin 8.3mg.

[0051] Texture properties (TA.XT texture analyzer): Hardness 2.85 kg, elasticity 0.92, cohesiveness 0.78, chewiness 2.04 kg.

[0052] Sensory evaluation (10 ratings, out of 5): Color 4.3, Flavor 4.1, Texture 4.2, Overall Acceptability 4.3. The product has a uniform light pink color, with the unique fresh ocean aroma of Antarctic krill and tuna, no fishy smell, and a moderately chewy, juicy, and refreshing texture.

[0053] (ix) Verification of uric acid-lowering function Fifty male Kunming mice (weighing 18–22 g) were randomly divided into five groups of 10 mice each after one week of acclimatization.

[0054] Blank control group: Orally administered normal saline Model group: Inosine (500 mg / kg) + potassium oxonate (100 mg / kg) administered by gavage Positive control group: administered hypoxanthine + potassium oxonate + allopurinol (10 mg / kg) by gavage. Low-dose sausage group: Oral administration of hypoxanthine + potassium oxonate + homogenate of cooked sausage (equivalent to 2g / kg body weight of sausage). High-dose sausage group: Oral administration of hypoxanthine + potassium oxonate + homogenate of cooked sausage (equivalent to 5g / kg body weight of sausage) After 10 days of continuous gavage, the patients were fasted for 12 hours. Blood was collected from the orbital fossa to separate serum and measure uric acid and creatinine. Liver tissue was taken to measure xanthine oxidase (XOD) activity.

[0055] Experimental results: (1) Serum uric acid level (μmol / L): blank control group 128.6±10.5; model group 276.5±23.2; positive control group 158.3±15.8; low-dose sausage group 215.6±19.4 (22.0% decrease compared with model group, P<0.05); high-dose sausage group 172.8±14.3 (37.5% decrease compared with model group, P<0.01).

[0056] (2) Liver XOD activity (U / mg prot): blank control group 17.8±2.2; model group 43.6±3.8; positive control group 25.4±3.1; low-dose sausage group 36.2±3.3 (P<0.05); high-dose sausage group 28.5±2.9 (P<0.01).

[0057] (3) Serum creatinine (μmol / L): blank control group 27.5±3.1; model group 50.2±5.0; low-dose sausage group 33.7±4.3; high-dose sausage group 29.0±3.9. All sausage groups were significantly lower than the model group (P<0.05), indicating that they have a protective effect on renal function.

[0058] The above results indicate that the composite sausage prepared by this invention has a significant uric acid-lowering function, and the effect is dose-dependent. Example

[0059] The difference between this embodiment and Embodiment 1 is that: (1) Step (a) Microwave thawing parameters are adjusted to power 250W / kg, frequency 2450MHz, temperature not exceeding 50℃, and thawing time 18min. The enzyme activity reduction rate is about 42%.

[0060] (2) In step (5), the enzymatic hydrolysis reaction temperature is 12℃, and the reaction time is extended to 16h. The degree of hydrolysis reaches 10.3%.

[0061] (3) In step (5) of the ingredients, the amount of krill-derived compound enzyme solution added is increased to 12 parts, and 0.2% of alkaline protease (food grade, enzyme activity 200,000 U / g) is added to carry out endogenous-exogenous enzyme synergistic enzymatic hydrolysis.

[0062] Experimental results: (1) Serum uric acid level (μmol / L): blank control group 127.3±15.2; model group 275.0±18.5; positive control group 156.4±20.5; low-dose sausage group 203.2±17.8 (26.1% decrease compared with model group); high-dose sausage group 157.3±15.8 (42.8% decrease compared with model group).

[0063] (2) Liver XOD activity (U / mg prot): blank control group 17.4±4.2; model group 44.9±5.4; positive control group 25.1±3.6; low-dose sausage group 31.6±4.8; high-dose sausage group 23.0±3.5.

[0064] (3) Serum creatinine (μmol / L): blank control group 26.8±3.9; model group 51.5±7.3; low-dose sausage group 31.2±6.1; high-dose sausage group 27.0±5.5. All sausage dose groups were significantly lower than the model group, indicating that they have a protective effect on renal function.

[0065] In the uric acid-lowering experiment, the serum uric acid level in the high-dose sausage group (5g / kg) was reduced by 42.8% compared with the model group, which was better than Example 1. This may be related to the longer low-temperature enzymatic hydrolysis time and the synergistic effect of exogenous enzymes, which resulted in a higher yield of uric acid-lowering active peptides. Example

[0066] The difference between this embodiment and Embodiment 1 is that: (1) Step (3) Low-temperature acid emulsification uses food-grade citric acid (1.5% addition) to replace lactic acid, and adjusts the pH to 5.8.

[0067] (2) The proportion of ingredients in step (5) is adjusted as follows: 35 parts Antarctic krill meat, 20 parts tuna blood and meat paste, 35 parts pork skin collagen paste, 8 parts krill-derived compound enzyme solution, and 2 parts ice water.

[0068] (3) Step (VII) Quick freezing is carried out using liquid nitrogen quick freezing method, freezing temperature -80℃, freezing time 15min, and the core temperature reaches below -25℃.

[0069] Experimental results: (1) Serum uric acid level (μmol / L): blank control group 128.9±13.1; model group 277.1±20.6; positive control group 158.9±12.3; low-dose sausage group 218.1±16.7 (21.3% decrease compared with model group); high-dose sausage group 179.6±15.6 (35.2% decrease compared with model group).

[0070] (2) Liver XOD activity (U / mg prot): blank control group 18.1±3.4; model group 45.3±6.2; positive control group 24.8±4.7; low-dose sausage group 38.5±2.8; high-dose sausage group 30.7±3.6.

[0071] (3) Serum creatinine (μmol / L): blank control group 27.2±4.5; model group 50.9±6.2; low-dose sausage group 35.4±5.5; high-dose sausage group 31.3±4.8. All sausage dose groups were significantly lower than the model group, indicating that they have a protective effect on renal function.

[0072] The resulting product has a higher collagen content in pigskin, a more elastic and crisp texture, and a chewiness of 3.15 kg, making it suitable for consumers who prefer a chewier texture. In the uric acid-lowering experiment, the high-dose group showed a 35.2% reduction in serum uric acid levels compared to the model group, with stable results. Example

[0073] The difference between this embodiment and Embodiment 1 is that: (1) In step (iv), the extraction of the krill-derived complex enzyme solution was carried out using a low-temperature autolysis-exogenous enzyme-assisted method: after the shrimp head mud was induced to autolyze by ultraviolet irradiation (20W, distance 0.8m, irradiation for 15min), 0.1% low-temperature protease was added, and the enzyme was extracted by enzymatic hydrolysis at 10℃ for 3h. The enzyme activity of the obtained complex enzyme solution reached 1850U / mL.

[0074] (2) Step (ii) Nitrogen protection uses a mixture of nitrogen (90%) and carbon dioxide (10%), with the oxygen concentration controlled below 0.5 vol%.

[0075] (3) The product is steamed (100℃, 12min) instead of baked. After steaming, the product has a slightly higher moisture content (62.3%) and a softer and juicier texture.

[0076] Experimental results: (1) Serum uric acid level (μmol / L): blank control group 128.1±18.4; model group 276.3±20.7; positive control group 158.0±19.3; low-dose sausage group 216.6±19.4 (21.6% decrease compared with model group); high-dose sausage group 174.6±14.3 (36.8% decrease compared with model group).

[0077] (2) Liver XOD activity (U / mg prot): blank control group 17.9±4.1; model group 44.2±5.7; positive control group 25.0±4.2; low-dose sausage group 36.8±4.9; high-dose sausage group 29.3±3.4.

[0078] (3) Serum creatinine (μmol / L): blank control group 27.0±5.9; model group 50.1±7.7; low-dose sausage group 34.3±5.8; high-dose sausage group 30.1±4.6. All sausage dose groups were significantly lower than the model group, indicating that they have a protective effect on renal function.

[0079] In the uric acid-lowering experiment, the serum uric acid level in the high-dose steamed sausage group was 36.8% lower than that in the model group. There was no significant difference in uric acid-lowering effect compared with the roasted product, indicating that different cooking methods have no significant impact on the uric acid-lowering function of the product.

[0080] The above embodiments illustrate that the method of the present invention can be flexibly adapted to different production scales and product demands by adjusting process parameters, ensuring stable product quality and reliable uric acid-lowering effects.

Claims

1. A method for preparing a composite sausage made from Antarctic krill, tuna, and collagen. Its features are, Includes the following steps: (1) Thaw the frozen Antarctic krill raw material at low temperature, and control the thawing temperature to not exceed 60°C. After thawing, remove the shell and collect the Antarctic krill meat. At the same time, collect the by-products. Store the shelled Antarctic krill meat at ultra-low temperature. (2) The tuna preserved at ultra-low temperature is cut and the blood-infused meat is removed under low temperature conditions of 0-4℃. During the cutting process, protective gas is used to protect the operation environment and the oxygen concentration is controlled to be below 1 vol%. After cutting, the blood-infused meat is minced into tuna blood-infused meat paste. (3) Using defatted pig back skin as raw material, the pig skin is subjected to low-temperature crushing, low-temperature mud stirring, low-temperature acid emulsification and low-temperature mechanical micro-grinding in sequence at 0-10℃ to obtain low-temperature raw pig skin collagen paste. (4) Grind the by-products collected in step (1) into shrimp head paste, add 4℃ low temperature reverse osmosis water for low temperature extraction, and obtain krill source complex enzyme solution by centrifugation; (5) Mix the Antarctic krill meat from step (1), the tuna blood-infused minced meat from step (2), the low-temperature raw pork skin collagen minced meat from step (3), and the krill-derived complex enzyme solution from step (4). Add ice water, salt, compound phosphate and spices, and carry out low-temperature enzymatic hydrolysis reaction at 10-25℃ for 8-16 hours. (6) The enzymatically hydrolyzed material is chopped at low temperature to obtain meat paste. During the chopping process, the material temperature is kept below 12°C. (7) The chopped meat paste is stuffed into sausage casings and then quick-frozen to produce frozen prepared composite meat sausages; (8) The composite sausage is thawed and cooked to obtain a composite sausage with uric acid reduction function. The composite sausage reduces serum uric acid level by 20-50%.

2. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, The thawing in step (1) includes microwave thawing, radio frequency thawing or low temperature running water thawing. The power of microwave thawing is 200-500W / kg, the frequency is 915MHz or 2450MHz, the thawing time is 5-20min, and the shrimp body temperature is controlled at 40-55℃.

3. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, The protective gas in step (2) is argon, nitrogen, or a mixture of 80-95% nitrogen and 5-20% carbon dioxide; the protein content of the tuna blood-infused meat is 75-81% on a dry basis, and the unsaturated fatty acid content accounts for 37-58% of the total fat.

4. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, In step (3), the particle size of the material crushed at low temperature is 2-5 mm. The low-temperature acid emulsification is carried out by emulsification with organic acid, which is food-grade lactic acid, citric acid, malic acid or tartaric acid. The amount added is 0.5-2.0% of the mass of pig skin paste. The emulsification pH value is 5.0-6.

0. The particle size of the material after low-temperature mechanical micro-grinding is 50-200 μm. The protein content of the obtained low-temperature raw pigskin collagen paste is ≥80% on a dry basis.

5. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, In step (4), the low-temperature extraction temperature is 4-10℃, the extraction time is 2-6h, the mass ratio of low-temperature reverse osmosis water to shrimp head mud is 2:1-5:1, and the centrifugation conditions are 4℃, 3000-5000rpm for 10-20min; the krill-derived complex enzyme solution contains trypsin, chymotrypsin and carboxypeptidase.

6. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, The weight proportions of each raw material in step (5) are as follows: 20-40 parts Antarctic krill meat, 15-35 parts tuna blood and meat paste, 20-40 parts low-temperature raw pork skin collagen paste, 5-15 parts krill-derived compound enzyme solution, 5-15 parts ice water, 0.5-2.0 parts salt, 0.1-0.5 parts compound phosphate, and 0.5-2.0 parts spices.

7. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, In step (5), exogenous alkaline protease or flavor protease is added.

8. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, In step (6), low-temperature chopping includes low-speed chopping and high-speed chopping. The conditions for low-speed chopping are 500-1000 rpm for 3-5 min, and the conditions for high-speed chopping are 2000-3000 rpm for 2-4 min. During the chopping process, ice water is added in batches to keep the material temperature below 12°C.

9. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, The quick-freezing process in step (7) includes tunnel quick-freezing, liquid nitrogen quick-freezing or plate quick-freezing.

10. The method for preparing a composite sausage made from Antarctic krill, tuna, and collagen according to claim 1, characterized in that, The cooking methods for the compound sausage in step (8) include roasting, frying or steaming; the protein content of the cooked compound sausage is ≥20% wet basis or ≥60% dry basis, and the unsaturated fatty acid content accounts for more than 40% of the total fatty acid content.