Treatment method for reducing purine in tilapia aquatic products

Abstract

The invention discloses a treatment method for reducing purine in tilapia aquatic products. According to the method, through collaborative innovation of a multi-dimensional technology, the nutrition safety and market adaptability of the tilapia aquatic products are remarkably improved, and efficient degradation of purine is achieved on the basis of the synergistic effect of the natural plant extract and the functional polysaccharide in combination with a microwave-ultrasonic physical field coupling technology. The process not only can accurately regulate and control the molecular structure of purine, but also can effectively retain the natural color and elastic taste of the fillets, and avoids the problems of nutrition loss and texture hardening caused by traditional high-temperature processing. Meanwhile, through cooperation of low-temperature gradient drying and a vacuum fresh-keeping process, generation of harmful substances in the processing process is inhibited, the shelf life of the product is prolonged, a stable quality basis is provided for subsequent prefabricated production, and through establishment of standardized process parameters and an accurate detection system, it is ensured that the purine content of different batches of products is stable and controllable; the strict requirements of specific people on low-purine food are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of aquatic product preparation, and specifically relates to a method for treating tilapia aquatic products to reduce purine content. Background Art

[0002] The purine removal technology for tilapia is a treatment process that aims at the high purine content in tilapia and uses physical, chemical or biological methods to reduce its purine content. This technology mainly includes steps such as raw material pretreatment, enzymatic hydrolysis, fermentation, adsorption, etc. Through the action of specific enzyme preparations or microorganisms, the purine in tilapia is decomposed or transformed into harmless substances, and then the residual purine is removed by adsorbents, thereby effectively reducing the purine content of tilapia products and meeting the needs of patients with gout and hyperuricemia for low-purine foods. The application of this technology not only improves the food safety of tilapia but also broadens the market application range of tilapia, which is of great significance for promoting the healthy development of the fishery industry and improving the quality of people's lives.

[0003] However, traditional purine removal methods often rely on soaking in a single chemical reagent or long-term high-temperature cooking, which easily leads to protein denaturation, loose texture and flavor loss of aquatic products, and has low degradation efficiency and poor stability for purine; at the same time, the traditional process parameters are fuzzy and lack precise control, making it difficult to meet the standardized requirements of industrial production. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for treating tilapia aquatic products to reduce purine content in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: A method for treating tilapia aquatic products to reduce purine content, the method comprising the following steps:

[0006] S1: Wash the tilapia raw materials and slice them, remove the internal organs and surface impurities, and drain the water for later use.

[0007] S2: Immerse the fish slices in a composite solution containing 0.3% - 0.5% natural plant extract and 1% - 1.5% functional polysaccharide, and let them stand at 4°C for 30 - 45 minutes to promote the release of purine degradation precursor substances.

[0008] S3: Place the fish slices in a microwave device, set the power to 500 - 800W and the time to 3 - 5 minutes, and through the non-thermal effect, change the molecular structure of purine and inhibit the activity of endogenous enzymes, so that the purine content is reduced by 15% - 22%.

[0009] S4: Use an ultrasonic device with a frequency of 25 - 40kHz and an intensity of 200 - 300W to treat the fish slices for 10 - 15 minutes, and through the cavitation effect, destroy the stability of purine molecules and further reduce the purine content by 8% - 12%.

[0010] S5: Transfer the fish slices treated with microwave-ultrasonic wave to a low-temperature environment of 4-8 °C to drain, and remove the residual solution and free purines.

[0011] S6: Perform vacuum tumbling on the fish slices, add 0.1%-0.3% flavor enhancer and 0.05% antioxidant to balance flavor loss and extend the shelf life.

[0012] S7: Adopt a segmented drying process: in the first stage, hot air dry at 40 °C for 30 minutes to remove surface moisture; in the second stage, vacuum dry at 25 °C until the moisture content ≤ 12%.

[0013] S8: Cut and shape the dried fish slices, and use modified atmosphere packaging or vacuum packaging, and store them in a cold chain at -18 °C to retain the low-purine characteristics.

[0014] S9: Use high performance liquid chromatography rapid detection method to quantitatively analyze the purine content of the final product, and ensure that the total purine content ≤ 120mg / 100g.

[0015] In a preferred embodiment, in step S1, select fresh tilapia as the raw material, use flowing clean water to rinse the mucus and impurities on the fish body surface, and use a professional slicing device to cut along the muscle texture on the back of the fish body into uniform fish slices with a thickness of 5-7 mm. Remove the remaining internal organs, fish bones and black peritoneum of the fish slices to ensure that the raw materials are clean and free of residues. Place the treated fish slices in a stainless steel sieve to drain for 10-15 minutes until there is no obvious moisture on the surface, and reserve them for the next process.

[0016] In a preferred embodiment, in step S2, prepare a composite solution of 0.3%-0.5% natural plant extract (such as green tea polyphenol) and 1%-1.5% functional polysaccharide (such as chitosan), dissolve it in cold water at 4 °C and stir evenly. Immerse the drained fish slices completely in the solution, and the material-liquid ratio is 1:3 (the weight of the fish slices to the volume of the solution), and let it stand in a low-temperature environment of 4 °C for 30-45 minutes. Through the synergistic effect of plant active ingredients and polysaccharides in this process, promote the dissolution of purine precursor substances and inhibit the activity of oxidase.

[0017] In a preferred embodiment, in step S3, lay the soaked fish slices flat on a special microwave tray, ensure a single-layer distribution and avoid overlapping. Set the power of the microwave equipment to 500-800W, and the processing time to 3-5 minutes. The specific parameters are adjusted according to the thickness of the fish slices: 500W is suitable for processing 5-mm thin slices for 5 minutes, and 800W is suitable for processing 7-mm thick slices for 3 minutes. The non-thermal effect of microwave promotes the breakage of purine molecular structure, and at the same time, the high-temperature instantaneous action inhibits the activity of endogenous enzymes. After processing, the central temperature of the fish slices needs to be controlled at 65-70 °C to ensure bright white color and firm texture.

[0018] In a preferred embodiment, in step S4, an ultrasonic device with a frequency of 25 - 40 kHz and an intensity of 200 - 300 W is used. The microwave-treated fish fillets are placed in a sealed treatment tank, and 4°C cold water is injected until the fish fillets are completely covered. The ultrasonic generator is started and processed for 10 - 15 minutes. The microjets generated by the cavitation effect continuously impact the fish fillet tissue, further destroying the purine molecular bonding structure and accelerating the dissolution of free purines. The processed fish fillets need to be taken out immediately to avoid soft texture caused by long-term soaking.

[0019] In a preferred embodiment, in step S5, the fish fillets treated by microwave-ultrasonic combination are transferred to a low-temperature environment of 4 - 8°C and laid flat on a multi-layer stainless steel grid rack to drain for 30 - 40 minutes. Through the dual mechanisms of gravity and low temperature inhibiting the proliferation of microorganisms, the residual composite solution and the dissolved free purines on the surface of the fish fillets are removed. The end point of draining is judged by the criterion that there are no continuous water drops falling on the surface of the fish fillets and the touch is slightly moist and not sticky.

[0020] In a preferred embodiment, in step S6, the drained fish fillets are put into a vacuum tumbler, and 0.1% - 0.3% of the fish fillet weight of yeast extract is added as a flavor enhancer, and 0.05% of rosmarinic acid is added as an antioxidant. The vacuum degree of the tumbler is set at -0.08 MPa, the rotation speed is 12 r / min, and the tumbling time is 20 minutes. This process enables the flavoring components to uniformly penetrate into the gaps between the fish fillet muscle fibers, and at the same time discharges the residual purines through physical extrusion, improving the product flavor and extending the shelf life.

[0021] In a preferred embodiment, in step S7, a two-stage drying process is adopted: in the first stage, the fish fillets are placed in a hot air drying oven at 40°C with a wind speed of 2 m / s and dried for 30 minutes to quickly remove the surface moisture; in the second stage, they are transferred to a vacuum dryer at 25°C with a vacuum degree of -0.09 MPa and continuously dried until the water content of the fish fillets ≤ 12%. The drying time is controlled at 2 - 3 hours according to the thickness of the fish fillets. The low-temperature gradient drying avoids the re-dissolution of purines caused by high temperature, and at the same time maintains the elasticity and chewiness of the fish fillets.

[0022] In a preferred embodiment, in step S8, the dried fish fillets are cut into standard slices with a length of 5 cm and a width of 2 cm according to specifications, or made into surimi products through minced meat recombination technology. A gas packaging machine is used to fill with a mixed gas of CO2 and N2 (volume ratio 6:4), or a vacuum packaging machine is used to pump to a vacuum degree of -0.1 MPa. The packaged products are immediately transferred to a -18°C cold storage for preservation, and the temperature fluctuation during the whole cold chain transportation does not exceed ±2°C to ensure the stability of the low-purine characteristics.

[0023] In a preferred embodiment, in step S9, the purine content of the finished product is detected by high performance liquid chromatography: the chromatographic column is a C18 reverse phase column (250 mm × 4.6 mm, 5 μm), the mobile phase is 0.02 mol / L potassium dihydrogen phosphate buffer (pH 3.8) and methanol (97:3), the flow rate is 1.0 mL / min, and the detection wavelength is 254 nm. 3% of the samples are randomly selected from each batch, and after pretreatment, they are analyzed on the machine. The total purine content must be ≤ 120 mg / 100 g to pass the quality acceptance.

[0024] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0025] 1. In the present invention, through multi-dimensional technological collaborative innovation, the nutritional safety and market adaptability of tilapia aquatic products have been significantly improved. On the one hand, based on the synergistic effect of natural plant extracts and functional polysaccharides, combined with the microwave-ultrasonic physical field coupling technology, the efficient degradation of purines has been achieved. This process can not only precisely regulate the purine molecular structure, but also effectively retain the natural color and elastic texture of the fish fillets, avoiding the nutritional loss and texture hardening problems caused by traditional high-temperature processing. At the same time, the combination of low-temperature gradient drying and vacuum fresh-keeping technology not only inhibits the generation of harmful substances during the processing, but also extends the shelf life of the product, providing a stable quality basis for subsequent prefabricated production.

[0026] 2. In the present invention, through the establishment of standardized process parameters and a precise detection system, the purine content of products in different batches is ensured to be stable and controllable, meeting the strict requirements of specific populations for low-purine foods. On the basis of maintaining the original fresh flavor, the processed tilapia products have formed a more competitive health attribute in the market, opening up a new development direction for the deep processing field of aquatic products. The environmental friendliness and energy utilization efficiency of the entire technical process also provide a practical reference for the green transformation of the food processing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the process principle of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0029] Example:

[0030] Refer to Figure 1 , a method for treating tilapia aquatic products to reduce purines, the method comprising the following steps:

[0031] S1: Wash the tilapia raw materials and slice them. Remove the internal organs and surface impurities, and drain the water for later use.

[0032] S2: Immerse the fish slices in a composite solution containing 0.3% - 0.5% natural plant extract and 1% - 1.5% functional polysaccharide, and let them stand at 4°C for 30 - 45 minutes to promote the release of purine degradation precursor substances.

[0033] S3: Place the fish slices in a microwave device, set the power to 500 - 800W and the time to 3 - 5 minutes. Through non-thermal effects, change the purine molecular structure and inhibit the activity of endogenous enzymes, reducing the purine content by 15% - 22%.

[0034] S4: Use an ultrasonic device with a frequency of 25 - 40kHz and an intensity of 200 - 300W to process the fish slices for 10 - 15 minutes. Through cavitation effects, destroy the stability of purine molecules and further reduce the purine content by 8% - 12%.

[0035] S5: Transfer the fish slices treated by microwave - ultrasonic combination to a low-temperature environment of 4 - 8°C to drain, removing the residual solution and free purine.

[0036] S6: Conduct vacuum tumbling treatment on the fish slices, adding 0.1% - 0.3% flavor enhancer and 0.05% antioxidant to balance flavor loss and extend the shelf life.

[0037] S7: Adopt a segmented drying process: in the first stage, dry with hot air at 40°C for 30 minutes to remove surface moisture; in the second stage, conduct vacuum drying at 25°C until the moisture content ≤ 12%.

[0038] S8: Cut and shape the dried fish slices, and use modified atmosphere packaging or vacuum packaging, and store them in a cold chain at -18°C to retain the low-purine characteristics.

[0039] S9: Use high-performance liquid chromatography rapid detection method to quantitatively analyze the purine content of the final product, ensuring that the total purine content ≤ 120mg / 100g.

[0040] In step S1, select fresh tilapia as the raw material, use running water to wash the mucus and impurities on the fish body surface, and use a professional slicing device to cut along the muscle texture on the back of the fish body into uniform fish slices with a thickness of 5 - 7 mm. Remove the remaining internal organs, fish bones and black peritoneum of the fish slices to ensure that the raw materials are clean and residue-free. Place the processed fish slices in a stainless steel sieve to drain water for 10 - 15 minutes until there is no obvious water on the surface, and set aside for the next process.

[0041] In step S2, a composite solution of natural plant extract (such as green tea polyphenols) with a concentration of 0.3% - 0.5% and functional polysaccharide (such as chitosan) with a concentration of 1% - 1.5% is prepared, dissolved in cold water at 4°C and stirred evenly. The drained fish slices are completely immersed in the solution, with a material-liquid ratio of 1:3 (the ratio of the weight of fish slices to the volume of the solution), and left standing for 30 - 45 minutes in a low-temperature environment at 4°C. Through the synergistic effect of plant active ingredients and polysaccharides in this process, the dissolution of purine precursor substances is promoted and the activity of oxidase is inhibited.

[0042] In step S3, the soaked fish slices are laid flat on a microwave-special tray, ensuring a single-layer distribution to avoid overlapping. The power of the microwave device is set at 500 - 800W, and the processing time is 3 - 5 minutes. The specific parameters are adjusted according to the thickness of the fish slices: 500W is suitable for processing 5-mm-thin slices for 5 minutes, and 800W is suitable for processing 7-mm-thick slices for 3 minutes. The non-thermal effect of microwaves causes the molecular structure of purines to break, and at the same time, the instantaneous high-temperature effect inhibits the activity of endogenous enzymes. After processing, the central temperature of the fish slices needs to be controlled at 65 - 70°C to ensure a bright white color and a firm texture.

[0043] In step S4, an ultrasonic device with a frequency of 25 - 40 kHz and an intensity of 200 - 300W is used. The fish slices after microwave treatment are placed in a sealed treatment tank, and cold water at 4°C is injected until the fish slices are completely covered. The ultrasonic generator is started to process for 10 - 15 minutes. The micro-jet generated by the cavitation effect continuously impacts the fish slice tissue, further destroying the bonding structure of purine molecules and accelerating the dissolution of free purines. After processing, the fish slices need to be taken out immediately to avoid softening of the texture caused by long-term soaking.

[0044] Drain on a multi-layer stainless steel grid rack for 30 - 40 minutes. Through the dual mechanisms of gravity and low-temperature inhibition of microbial proliferation, the residual composite solution and dissolved free purines on the surface of the fish slices are removed. The end point of draining is judged by the criterion that there are no continuous water drops falling on the surface of the fish slices and the touch is slightly moist and not sticky.

[0045] In step S6, the drained fish slices are put into a vacuum tumbler, adding 0.1% - 0.3% of the fish slice weight of yeast extract as a flavor enhancer and 0.05% of rosmarinic acid as an antioxidant. The vacuum degree of the tumbler is set at -0.08 MPa, the rotation speed is 12 r / min, and the tumbling time is 20 minutes. This process allows the flavoring components to evenly penetrate into the muscle fiber gaps of the fish slices, and at the same time, residual purines are discharged through physical extrusion, improving the product flavor and extending the shelf life.

[0046] In step S7, a two-stage drying process is adopted: in the first stage, the fish slices are placed in a hot air drying oven at 40°C with a wind speed of 2 m / s and dried for 30 minutes to quickly remove the surface moisture; in the second stage, they are transferred to a vacuum dryer at 25°C with a vacuum degree of -0.09 MPa and continuously dried until the water content of the fish slices ≤ 12%. The drying time is controlled at 2 - 3 hours according to the thickness of the fish slices. The low-temperature gradient drying avoids the re-dissolution of purines caused by high temperature and maintains the elasticity and chewiness of the fish slices at the same time.

[0047] In step S8, the dried fish slices are cut into standard slices with a length of 5 cm and a width of 2 cm according to specifications, or made into surimi products through minced meat recombination technology. A gas flushing packaging machine is used to fill with a mixed gas of CO2 and N2 (volume ratio 6:4), or a vacuum packaging machine is used to pump to a vacuum degree of -0.1 MPa. The packaged products are immediately transferred to a cold storage at -18°C for storage, and the temperature fluctuation during the whole cold chain transportation does not exceed ±2°C to ensure the stability of the low-purine characteristics.

[0048] In step S9, the high-performance liquid chromatography method is used to detect the purine content of the finished products: the chromatographic column is a C18 reversed-phase column (250 mm × 4.6 mm, 5 μm), the mobile phase is 0.02 mol / L potassium dihydrogen phosphate buffer solution (pH 3.8) and methanol (97:3), the flow rate is 1.0 mL / min, and the detection wavelength is 254 nm. 3% of the samples are randomly selected from each batch, pretreated and then analyzed on the machine. The total purine content must ≤ 120 mg / 100 g to pass the quality acceptance.

[0049] It can be seen from the above that in the present invention, through the collaborative innovation of multi-dimensional technologies, the nutritional safety and market adaptability of tilapia aquatic products have been significantly improved. On the one hand, based on the synergistic effect of natural plant extracts and functional polysaccharides, combined with the microwave-ultrasonic physical field coupling technology, the efficient degradation of purines is realized. This process can not only accurately regulate the molecular structure of purines, but also effectively retain the natural color and elastic texture of the fish slices, avoiding the problems of nutrient loss and texture hardening caused by traditional high-temperature processing. At the same time, the cooperation of low-temperature gradient drying and vacuum fresh-keeping technology not only inhibits the generation of harmful substances during the processing, but also extends the shelf life of the products, providing a stable quality basis for subsequent prefabricated production.

[0050] In the present invention, through the establishment of standardized process parameters and a precise detection system, the purine content of products in different batches is ensured to be stable and controllable, meeting the strict requirements of specific populations for low-purine foods. On the basis of maintaining the original fresh flavor, the processed tilapia products have formed a more competitive health attribute in the market, opening up a new development direction for the deep processing field of aquatic products. The environmental friendliness and energy utilization efficiency of the whole set of technical processes also provide a practical reference for the green transformation of the food processing industry.

[0051] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing purine in tilapia aquatic products, characterized in that: The method comprises the following steps: S1: Raw material pretreatment: wash and slice the tilapia, remove impurities and drain; S2: Soaking in composite solution: The fish fillets were immersed in a 4°C solution containing 0.3%-0.5% natural plant extract and 1%-1.5% functional polysaccharide for 30-45 minutes; S3: Microwave treatment: 500-800W microwave treatment for 3-5 minutes to inhibit enzyme activity and degrade purine; S4: Ultrasonic treatment: 25-40kHz, 200-300W ultrasonic treatment for 10-15 minutes to destroy the purine structure; S5: Low temperature draining: remove residual liquid and free purine at 4-8℃; S6: Vacuum tumbling: Add 0.1%-0.3% flavor enhancer and 0.05% antioxidant to tumble and lock in freshness; S7: Staged drying: hot air drying at 40°C for 30 minutes, followed by vacuum drying at 25°C until the moisture content is ≤12%; S8: Packaging and storage: After cutting, use gas conditioning or vacuum packaging and store in a cold chain at -18℃; S9: Quality inspection: Total purine content determined by HPLC ≤ 120 mg / 100 g.

2. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S1, fresh tilapia is selected as a raw material, mucus and impurities on the surface of the fish body are washed with running clean water, and professional slicing equipment is used to cut the fish body into uniform fish fillets with a thickness of 5-7 mm along the muscle texture of the back of the fish body; the internal organs, fish bones and black peritoneum remaining in the fish fillets are removed to ensure that the raw materials are clean and free of residue; the processed fish fillets are placed in a stainless steel sieve to drain for 10-15 minutes until there is no obvious moisture on the surface, and then standby for the next process.

3. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S2, a composite solution of natural plant extracts with a concentration of 0.3% to 0.5% and functional polysaccharides with a concentration of 1% to 1.5% is prepared, dissolved in 4°C cold water and stirred evenly; the drained fish fillets are completely immersed in the solution with a material-liquid ratio of 1:3, and allowed to stand in a low temperature environment of 4°C for 30 to 45 minutes; this process promotes the dissolution of purine precursors and inhibits oxidase activity through the synergistic effect of plant active ingredients and polysaccharides.

4. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S3, the soaked fish fillets are spread on a microwave tray to ensure single-layer distribution and avoid overlap; the microwave equipment power is set to 500-800W, and the processing time is 3-5 minutes. The specific parameters are adjusted according to the thickness of the fish fillets: 500W is suitable for 5-mm thin slices for 5 minutes, and 800W is suitable for 7-mm thick slices for 3 minutes; the non-thermal effect of microwaves promotes the breakage of the purine molecular structure, and the instantaneous effect of high temperature inhibits the activity of endogenous enzymes. The center temperature of the fish fillets after processing needs to be controlled at 65-70°C to ensure a bright white color and a firm texture.

5. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S4, an ultrasonic device with a frequency of 25-40kHz and an intensity of 200-300W is used to place the microwave-treated fish fillets in a closed treatment tank, and 4°C cold water is injected until the fish fillets are completely covered; the ultrasonic generator is started for treatment for 10-15 minutes, and the microjets generated by the cavitation effect continuously impact the fish fillet tissue, further destroying the bonding structure of the purine molecules and accelerating the dissolution of free purine; the fish fillets need to be taken out immediately after treatment to avoid long-term soaking resulting in soft and rotten texture.

6. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S5, the fish fillets treated with microwave-ultrasound are transferred to a low-temperature environment of 4-8°C, and spread on a multi-layer stainless steel grid rack to drain for 30-40 minutes; the residual composite solution and dissolved free purine on the surface of the fish fillets are removed by the dual mechanism of gravity and low temperature inhibition of microbial proliferation; the end point of draining is determined by the absence of continuous water droplets falling on the surface of the fish fillets and the touch feeling being slightly moist and non-sticky.

7. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S6, the drained fish fillet is put into a vacuum tumbling machine, 0.1% to 0.3% of the weight of the fish fillet yeast extract is added as a flavor enhancer, and 0.05% of rosmarinic acid is added as an antioxidant; the vacuum degree of the tumbling machine is set to -0.08MPa, the speed is 12r / min, and the tumbling time is 20 minutes; This process allows the flavoring ingredients to evenly penetrate the gaps between the fish fillet muscle fibers, while at the same time removing residual purines through physical extrusion, improving the product flavor and extending the shelf life.

8. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In step S7, a two-stage drying process is adopted: in the first stage, the fish fillet is placed in a hot air drying oven at 40° C., with a wind speed of 2 m / s, and dried for 30 minutes to quickly remove surface moisture; In the second stage, the fish fillets are placed in a 25°C vacuum dryer with a vacuum degree of -0.09MPa and continue drying until the moisture content of the fish fillets is ≤12%. The drying time is controlled within 2-3 hours depending on the thickness of the fish fillets. Low-temperature gradient drying avoids the redissolution of purines caused by high temperature, while maintaining the elasticity and chewiness of the fish fillets.

9. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In the step S8, the dried fish fillets are cut into standard slices of 5 cm in length and 2 cm in width according to specifications, or minced meat is reorganized into fish paste products; a modified atmosphere packaging machine is used to fill the mixture of CO2 and N2, or a vacuum packaging machine is used to evacuate the mixture to a vacuum degree of -0.1 MPa; the packaged products are immediately transferred to a -18°C cold storage for storage, and the temperature fluctuation during the entire cold chain transportation process does not exceed ±2°C, ensuring the stability of the low-purine characteristics.

10. A method for reducing purine in tilapia aquatic products as claimed in claim 1, characterized in that: In step S9, high performance liquid chromatography is used to detect the purine content of the finished product: the chromatographic column is a C18 reverse phase column, the mobile phase is 0.02 mol / L potassium dihydrogen phosphate buffer and methanol, the flow rate is 1.0 mL / min, and the detection wavelength is 254 nm; 3% of the samples are randomly selected from each batch, and after pre-treatment, they are analyzed on the machine. The total purine content must be ≤120 mg / 100 g to pass the quality acceptance.

Images