Metapenaeus ensis depurination method based on double-physical-field thermal processing and double-enzyme simulated digestion

Abstract

The invention discloses a metapenaeus ensis depurination process method based on double-physical-field thermal processing and double-enzyme simulated digestion. The method comprises the following steps: cleaning fresh metapenaeus ensis, removing shrimp lines, and absorbing moisture on the surface of the metapenaeus ensis by using special paper for a kitchen to obtain fresh metapenaeus ensis to be processed; the method comprises the following steps: putting a to-be-processed metapenaeus ensis meat pie into a micro steaming and baking integrated machine, carrying out hot air heating processing, then continuously carrying out high-temperature steam processing to obtain primary depurinated metapenaeus ensis meat, and then carrying out double-enzyme digestion treatment on the depurinated metapenaeus ensis meat to obtain secondary depurinated metapenaeus ensis. The two thermal processing modes are combined with double-enzyme digestion treatment to form the depurination method based on two-physical-field thermal processing and double-enzyme simulated digestion. The processing method provided by the invention has the effect of reducing the content of purine in the metapenaeus ensis, can be used for making low-purine metapenaeus ensis, and provides an experimental basis and a scientific basis for research on thermal physical field processing and reduction of the content of purine in food by an enzymic method.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a depurination method based on dual physical field thermal processing and dual enzyme simulated digestion. Background Art

[0002] As people pay more and more attention to healthy diet, reducing the purine content in food has become an important research direction in the field of food science. Purine is the final product of nucleic acid degradation metabolism in the body, and its excessive content is closely related to metabolic diseases such as gout and hyperuricemia. Therefore, the development of effective depurination methods is of great significance for improving food safety and preventing related diseases.

[0003] Existing depurination methods mainly include boiling, adsorption, salting-out-adsorption, alkaline treatment, ultrasonic treatment and microecological method. However, each of these methods has its own limitations. For example, although the boiling method is simple and easy, it will lead to a large loss of nutrients in food and cannot meet the needs of people who like non-boiled processed food; although the adsorption method, salting-out-adsorption method and other methods can remove some purines, the removal efficiency and safety need to be further improved; alkaline treatment, although the depurination effect is good, it will destroy the nutrients in food and produce toxic by-products, posing a potential threat to human health.

[0004] With the continuous advancement of science and technology, thermal processing technology and bio-enzyme method have gradually become new ways to reduce the purine content in food. Thermal processing technology can effectively control the purine in food by changing the microstructure and properties of the material. The bio-enzyme method uses the catalytic effect of enzymes, and the digestion technology has the advantages of mild reaction conditions, few by-products, and little damage to food nutrients. It can accurately degrade purine molecules in food.

[0005] Based on the above background, the present invention proposes a depurination method for shrimp based on dual physical field thermal processing and dual enzyme simulated digestion. The method combines the advantages of dual physical field thermal processing technology and dual enzyme simulated digestion technology, and realizes efficient and rapid removal of total purine content in food, especially hypoxanthine, through the action of physical field and catalytic action of enzyme. This method not only overcomes the limitations of existing depurination methods, but also utilizes the enzyme catalysis in dual enzyme simulated digestion technology to degrade purine molecules into harmless or low-toxic products. By optimizing the combination of technologies and parameter settings, the depurination effect can be further improved while retaining the nutrients in shrimp.

[0006] In summary, the present invention aims to provide a more efficient, safe and flexible method for depurinating shrimp to meet the dietary needs of patients with hyperuricemia and gout and promote the further development of food processing technology. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention aims to provide a depurination method for shrimp based on dual physical field thermal processing and dual enzyme simulated digestion, so as to solve the problems of nutrient loss and toxic by-product generation caused by traditional depurination methods, and achieve efficient and safe removal of purine components in shrimp.

[0008] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0009] The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion provided by the present invention comprises the following steps: (1) Wash the fresh shrimps, remove the shrimp threads, and then use kitchen paper to absorb the moisture on the surface of the shrimps to obtain the shrimp meat to be processed by heat; (2) placing the shrimp meat patties to be heat-processed in step (1) in a microwave oven, placing a temperature probe in the center of the shrimp meat, and setting upper and lower hot air heating; (3) After cooking with the upper and lower hot air heating program, immediately set the microwave oven program to the steam heating program for processing; (4) After cooking by the steam heating process, the heat-processed shrimp meat is immediately placed in the digestive juice for digestion.

[0010] Furthermore, in step (1), the fresh shrimps are produced under artificial breeding conditions and have a mass of 20-30 g per shrimp.

[0011] Furthermore, the power of the upper and lower hot air heating program in step (2) is 1450-1650 W, the program operating temperature is 130-150° C., the operating time is 170-190 s, the center temperature of the shrimp increases from 20-25° C. to 40-45° C., and the shrimp to be heat-processed is placed in a ceramic baking tray.

[0012] Furthermore, the power of the steam heating program in step (3) is 1400-1600 W, the program operating temperature is 138-142°C, the operating time is 50-70 s, the center temperature of the shrimp increases from 40-45°C to 65-70°C, and the shrimp to be heat-processed is placed in a ceramic baking tray.

[0013] Furthermore, the enzymes in the double enzyme digestion in step (4) are pepsin and gastric lipase, the digestive enzymes are pepsin and trypsin, the pepsin digestion time is 40-50 min, and the trypsin digestion time is 140-160 min.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Compared with the traditional single physical field or chemical method, the synergistic effect of the dual physical field in the method provided by the present invention can more effectively destroy the cell structure of the biomaterial and promote the release and decomposition of purine. At the same time, the dual enzyme simulated digestion further accelerates this process, significantly improving the depurination efficiency.

[0015] 2. Dual physical field thermal processing can usually complete the depurination process at a lower temperature and in a shorter time, reducing the damage to the quality of raw materials (such as color, taste, aroma, tissue state and taste, etc.) caused by high temperature and long-term treatment. Dual enzyme simulated digestion also helps to maintain the natural properties of raw materials with its mild and efficient characteristics.

[0016] 3. This method avoids the use of large amounts of chemical reagents and the production of harmful byproducts, thereby reducing environmental pollution. At the same time, the use of dual physical fields and dual enzymes are based on the principles of biophysics and biochemistry, which are more in line with the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a bar graph of the purine content of raw prawn meat and prawns processed by the dual physical field combination of upper and lower hot air + steam thermal processing in Example 1-3.

[0018] Figure 2 It is a graph of the purine content of shrimp after dual physical field combination processing in different orders in Example 1 and Comparative Example 2.

[0019] Figure 3 This is a graph of the purine content of shrimp after processing with three physical fields in different orders in comparative example 2-3.

[0020] Figure 4 This is a graph showing the purine content of shrimp after hot air heat processing at different temperatures in Examples 4-6.

[0021] Figure 5 This is a graph showing the purine content of shrimp after microwave heat processing at different intensities in Comparative Examples 7-9.

[0022] Figure 6 This is a graph showing the purine content of shrimp after steam heat processing at different temperatures in comparative examples 10-12.

[0023] Figure 7 It is a sensory evaluation diagram of the purine of shrimp after processing in Example 1 and different physical field combinations.

[0024] Figure 8 It is a graph of the depurine content of shrimp after double enzyme treatment in Example 1 and the untreated control.

[0025] Fig. 9 It is a graph showing the uric acid content generated by shrimps after being treated with the double enzyme method in Example 1 and the untreated control. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0027] Example 1 The method for depurinating shrimp based on dual physical field thermal processing comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed by double physical field superposition (140℃ upper and lower tube hot air heating + 140℃ steam heating) until the center temperature of the prawn meat reached 70℃, wherein the upper and lower tube hot air processing mode was the first physical field, the power of the upper and lower tube hot air processing was 1550 W, the running time was 180 s, the hot air temperature was 140℃, and the center temperature of the prawn meat increased from 25℃ to 45℃; the steam processing mode was the second physical field, the power of the steam heat processing was 1550 W, the heating temperature was 140℃, the running time was 60 s, and the center temperature of the prawn meat increased from 45℃ to 70℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, evaporated to dryness, and 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0028] Table 1 Parameters of double physical field combined processing of shrimp

[0029] Example 2 The method for depurinating shrimp based on dual physical field thermal processing comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed by double physical field superposition (135℃ upper and lower tube hot air heating + 142℃ steam heating) until the center temperature of the prawn meat reached 70℃, wherein the upper and lower tube hot air processing mode was the first physical field, the power of the upper and lower tube hot air processing was 1450 W, the running time was 190 s, the hot air temperature was 135℃, and the center temperature of the prawn meat increased from 25℃ to 43℃; the steam processing mode was the second physical field, the power of the steam heat processing was 1600 W, the heating temperature was 142℃, the running time was 50 s, the center temperature of the prawn meat increased from 43℃ to 70℃, and the prawn meat with the first depurination was obtained. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, evaporated to dryness, and 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0030] Table 2 Parameters of double physical field combined processing of shrimp

[0031] Example 3 The method for depurinating shrimp based on dual physical field thermal processing comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed by double physical field superposition (145℃ upper and lower tube hot air heating + 138℃ steam heating) until the center temperature of the prawn meat reached 70℃, wherein the upper and lower tube hot air processing mode was the first physical field, the power of the upper and lower tube hot air processing was 1650 W, the running time was 170 s, the hot air temperature was 145℃, and the center temperature of the prawn meat increased from 25℃ to 46℃; the steam processing mode was the second physical field, the power of the steam heat processing was 1400 W, the heating temperature was 138℃, the running time was 70 s, and the center temperature of the prawn meat increased from 46℃ to 70℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, evaporated to dryness, and 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0032] Table 3 Parameters of double physical field combined processing of shrimp

[0033] Example 4 The sensory evaluation standard of shrimp after dual physical field processing includes the following steps: Eight evaluators with certain professional backgrounds were selected to conduct sensory evaluation on the shrimp processed in the physical field. The evaluation criteria for the food are as follows.

[0034] Table 4 Sensory evaluation standards for shrimp

[0035] Example 5 The method for secondary release of purine from shrimp based on the double enzyme method comprises the following steps: Accurately weigh 5 g of minced purine-reducing physical field processed shrimp meat sample into a 50 mL centrifuge tube, add 4 mL SSF1.25× and 1 mL distilled water and place in a 37°C constant temperature shaker. The second stage, gastric digestion for 45 min. Add 8 mL SGF 1.25×, 0.667 mL pepsin solution, and 0.48 mL gastric lipase solution to the oral digestion system, and adjust the pH to 3. The third stage: intestinal digestion for 150 min. Add 8 mL SIF 1.25×, 5 mL trypsin solution, and 3 mL bile salt solution to the gastric digestion system, and adjust the pH to 7. The enzyme activities of pepsin, gastric lipase, and trypsin are 15000, 30000, and 250 U / mg, respectively. The system after in vitro simulated digestion was centrifuged at 8000 g and 4°C for 10 min and the supernatant A was collected. Take part of the supernatant A and mix it with 60% perchloric acid at a ratio of 10:1 v / v (the final concentration of perchloric acid is about 10:1). Then centrifuge at 8000 g and 4°C for 10 min to collect the supernatant B. HPLC is used to determine the purine concentration in the supernatant B. The purine content released into the solution after simulated digestion of the food is obtained by conversion. The degree of purine release can also be further obtained. The specific calculation formula is as follows: W= ×100 (3-1) DR= ×100 (3-2) In formula (3-1), W represents the purine content that can be released into the digestive fluid of shrimp after simulated digestion under the condition of 100 g dry weight, mg / 100g; C B represents the purine concentration in supernatant B, mg / L; V represents the volume of the digestion endpoint solution, 40 mL; m represents the dry weight corresponding to 5 g of sample.

[0036] In formula (3-2), M represents the total amount of purine obtained from shrimps under 100 g dry weight after purine reduction physical field processing. DR represents the secondary release degree of purine, that is, the proportion of free purine that can be released into the digestive fluid of shrimps after simulated digestion to the total amount of purine in the food.

[0037] Example 6 The method for secondary release of purine from shrimp based on the double enzyme method comprises the following steps: Accurately weigh 5 g of minced purine-reducing physical field processed shrimp meat sample into a 50 mL centrifuge tube, add 4 mL SSF1.25× and 1 mL distilled water and place in a 36°C constant temperature shaker. The second stage, gastric digestion for 40 min. Add 8 mL SGF 1.25×, 0.667 mL pepsin solution, and 0.48 mL gastric lipase solution to the oral digestion system, and adjust the pH to 3. The third stage: intestinal digestion for 160 min. Add 8 mL SIF 1.25×, 5 mL trypsin solution, and 3 mL bile salt solution to the gastric digestion system, and adjust the pH to 7. The enzyme activities of pepsin, gastric lipase, and trypsin are 15000, 30000, and 250 U / mg, respectively. The system after in vitro simulated digestion was centrifuged at 8000 g and 4°C for 10 min and the supernatant A was collected. Take part of the supernatant A and mix it with 60% perchloric acid at a ratio of 10:1 v / v (the final concentration of perchloric acid is about 10:1). Then centrifuge at 8000 g and 4°C for 10 min to collect the supernatant B. HPLC is used to determine the purine concentration in the supernatant B. The purine content released into the solution after simulated digestion of the food is obtained by conversion. The degree of purine release can also be further obtained. The specific calculation formula is as follows: W= ×100 (3-1) DR= ×100 (3-2) In formula (3-1), W represents the purine content that can be released into the digestive fluid of shrimp after simulated digestion under the condition of 100 g dry weight, mg / 100g; C B represents the purine concentration in supernatant B, mg / L; V represents the volume of the digestion endpoint solution, 40 mL; m represents the dry weight corresponding to 5 g of sample.

[0038] In formula (3-2), M represents the total amount of purine obtained from shrimps under 100 g dry weight after purine reduction physical field processing. DR represents the secondary release degree of purine, that is, the proportion of free purine that can be released into the digestive fluid of shrimps after simulated digestion to the total amount of purine in the food.

[0039] Example 7 The method for secondary release of purine from shrimp based on the double enzyme method comprises the following steps: Accurately weigh 5 g of minced purine-reducing physical field processed shrimp meat sample into a 50 mL centrifuge tube, add 4 mL SSF1.25× and 1 mL distilled water and place in a 36°C constant temperature shaker. The second stage, gastric digestion for 50 min. Add 8 mL SGF 1.25×, 0.667 mL pepsin solution, and 0.48 mL gastric lipase solution to the oral digestion system, and adjust the pH to 3. The third stage: intestinal digestion for 140 min. Add 8 mL SIF 1.25×, 5 mL trypsin solution, and 3 mL bile salt solution to the gastric digestion system, and adjust the pH to 7. The enzyme activities of pepsin, gastric lipase, and trypsin are 15000, 30000, and 250 U / mg, respectively. The system after in vitro simulated digestion was centrifuged at 8000 g and 4°C for 10 min and the supernatant A was collected. Take part of the supernatant A and mix it with 60% perchloric acid at a ratio of 10:1 v / v (the final concentration of perchloric acid is about 10:1). Then centrifuge at 8000 g and 4°C for 10 min to collect the supernatant B. HPLC is used to determine the purine concentration in the supernatant B. The purine content released into the solution after simulated digestion of the food is obtained by conversion. The degree of purine release can also be further obtained. The specific calculation formula is as follows: W= ×100 (3-1) DR= ×100 (3-2) In formula (3-1), W represents the purine content that can be released into the digestive fluid of shrimp after simulated digestion under the condition of 100 g dry weight, mg / 100g; C B represents the purine concentration in supernatant B, mg / L; V represents the volume of the digestion endpoint solution, 40 mL; m represents the dry weight corresponding to 5 g of sample.

[0040] In formula (3-2), M represents the total amount of purine obtained from shrimps under 100 g dry weight after purine reduction physical field processing. DR represents the secondary release degree of purine, that is, the proportion of free purine that can be released into the digestive fluid of shrimps after simulated digestion to the total amount of purine in the food.

[0041] Example 8 The depurinating double physical field processed shrimp produces uric acid effect after double enzyme digestion, including the following steps: A mother liquor with an XO enzyme activity of 1 U / mL was selected and added to supernatant A (Example 4) to make a final XO concentration of 0.1 U / mL. After vortex mixing, the mixture was incubated at 37°C for 45 min. After the incubation, the enzyme was inactivated in a boiling water bath for 10 min. After cooling to room temperature, the mixture was centrifuged at 8000 g and 4°C for 10 min. The supernatant was analyzed by the HPLC method in Example 1.

[0042] Comparative Example 1 The double physical field thermal processing method for depurinating shrimp comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave-steam-bake machine, and the temperature probe was placed in the center of the meat patty, and the prawns were processed by superposition of three physical fields (high-intensity microwave + 140°C steam heating) until the center temperature of the prawn meat reached 70°C, wherein the microwave processing mode was the first physical field, the microwave processing power was 1700 W, the operating time was 10 s, the frequency was 2450 MHz, and the center temperature of the prawn meat increased from 25°C to 45°C; the steam processing mode was the second physical field, the steam heat processing power was 1500 W, the heating temperature was 140°C, the operating time was 60 s, and the center temperature of the prawn meat increased from 45°C to 70°C, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0043] Table 5 Parameters of double physical field combined processing of shrimp

[0044] Comparative Example 2 The method for depurinating shrimp by three physical field thermal processing comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat pie, and the prawns were processed by superposition of three physical fields (high-intensity microwave + 140°C upper and lower tube hot air heating + 140°C steam heating) until the center temperature of the prawn meat reached 70°C, wherein the microwave processing mode was the first physical field, the microwave processing power was 1700 W, the running time was 5 s, the frequency was 2450 MHz, and the center temperature of the prawn meat increased from 25°C to 36°C; the upper and lower tube hot air processing mode was the second physical field, the upper and lower tube hot air processing power was 1550 W, the running time was 150 s, the hot air temperature was 140°C, and the center temperature of the prawn meat increased from 36°C to 56°C; the steam processing mode was the third physical field, the steam heat processing power was 1550 W, the heating temperature was 140°C, the running time was 45 s, the center temperature of the shrimp meat increased from 56°C to 70°C, and the shrimp meat with the first depurination was obtained. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, evaporated to dryness, and 10 mL of mobile phase A (pH 3.8 and containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution is ultrapure water) was added to dissolve the purine under the assistance of ultrasound, and after ultrasound, it was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the content of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0045] Table 6 Parameters of shrimp processing by three physical fields

[0046] Comparative Example 3 The method for depurinating shrimp by three physical field thermal processing comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat pie, and the prawns were processed by superposition of three physical fields (140°C upper and lower tube hot air heating + high-intensity microwave + 140°C steam heating) until the center temperature of the prawn meat reached 70°C, wherein the upper and lower tube hot air processing method was the first physical field, the power of the upper and lower tube hot air processing was 1550 W, the running time was 150 s, the hot air temperature was 140°C, and the center temperature of the prawn meat increased from 25°C to 36°C; the microwave processing method was the second physical field, the power of the microwave processing was 1700 W, the running time was 5 s, the frequency was 2450 MHz, and the center temperature of the prawn meat increased from 36°C to 56°C; the steam processing method was the third physical field, the power of the steam heat processing was 1550 W, the heating temperature was 140°C, the running time was 45 s, the center temperature of the shrimp meat increased from 56°C to 70°C, and the shrimp meat with the first depurination was obtained. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, evaporated to dryness, and 10 mL of mobile phase A (pH 3.8 and containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution is ultrapure water) was added to dissolve the purine under the assistance of ultrasound, and after ultrasound, it was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the content of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0047] Table 7 Parameters of shrimp processing by three physical fields

[0048] Comparative Example 4 The method for depurinating shrimp by upper and lower tube hot air heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed with a single physical field (100 ℃ upper and lower tube hot air heating) until the center temperature of the prawn meat reached 70 ℃, wherein the power of the upper and lower tube hot air processing was 1550 W, the operating time was 1060 s, the hot air temperature was 100 ℃, and the center temperature of the prawn meat increased from 25 ℃ to 70 ℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0049] Table 8 Parameters of single physical field combined processing of shrimp

[0050] Comparative Example 5 The method for depurinating shrimp by upper and lower tube hot air heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed with a single physical field (120℃ upper and lower tube hot air heating) until the center temperature of the prawn meat reached 70℃, wherein the power of the upper and lower tube hot air processing was 1550 W, the operating time was 710 s, the hot air temperature was 120℃, and the center temperature of the prawn meat increased from 25℃ to 70℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445× g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0051] Table 9 Parameters of single physical field combined processing of shrimp

[0052] Comparative Example 6 The method for depurinating shrimp by upper and lower tube hot air heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed with a single physical field (140 ℃ upper and lower tube hot air heating) until the center temperature of the prawn meat reached 70 ℃, wherein the power of the upper and lower tube hot air processing was 1550 W, the operating time was 440 s, the hot air temperature was 140 ℃, and the center temperature of the prawn meat increased from 25 ℃ to 70 ℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445× g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0053] Table 10 Parameters of single physical field combined processing of shrimp

[0054] Comparative Example 7 The method for depurinating shrimp by microwave heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed. The prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the patty. The prawns were heated in a single physical field (low-intensity microwave heating) until the center temperature of the prawn meat reached 70°C. The power of the microwave heat processing was 1700 W, the operating time was 120 s, and the center temperature of the prawn meat increased from 25°C to 70°C, thereby obtaining the prawn meat that had undergone the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0055] Table 11 Parameters of single physical field combined processing of shrimp

[0056] Comparative Example 8 The method for depurinating shrimp by microwave heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed. The prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the patty. The prawns were heated in a single physical field (medium-intensity microwave heating) until the center temperature of the prawn meat reached 70°C. The power of the microwave heat processing was 1700 W, the operating time was 30 s, and the center temperature of the prawn meat increased from 25°C to 70°C, thereby obtaining the prawn meat that had undergone the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0057] Table 12 Parameters of single physical field combined processing of shrimp

[0058] Comparative Example 9 The method for depurinating shrimp by microwave heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed. The prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the patty. The prawns were heated in a single physical field (high-intensity microwave heating) until the center temperature of the prawn meat reached 70°C. The power of the microwave heat processing was 1700 W, and the operating time was 20 s. The center temperature of the prawn meat increased from 25°C to 70°C, and the prawn meat that had undergone the first depurination was obtained. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0059] Table 13 Parameters of single physical field combined processing of shrimp

[0060] Comparative Example 10 The method for depurinating shrimp by steam heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed with a single physical field (100 ℃ steam heating) until the center temperature of the prawn meat reached 70 ℃, wherein the power of the steam heat processing was 1500 W, the operating time was 210 s, the operating temperature was 100 ℃, and the center temperature of the prawn meat increased from 25 ℃ to 70 ℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0061] Table 14 Parameters of single physical field combined processing of shrimp

[0062] Comparative Example 11 The method for depurinating shrimp by steam heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed with a single physical field (120 ℃ steam heating) until the center temperature of the prawn meat reached 70 ℃, wherein the power of the steam heat processing was 1500 W, the operating time was 195 s, the operating temperature was 120 ℃, and the center temperature of the prawn meat increased from 25 ℃ to 70 ℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0063] Table 15 Parameters of single physical field combined processing of shrimp

[0064] Comparative Example 12 The method for depurinating shrimp by steam heating comprises the following steps: About 100 g of fresh prawns were washed and deveined, and then the surface moisture of the fresh prawns was absorbed with kitchen paper to obtain the prawns to be heat-processed; the prawns to be heat-processed were put into a microwave oven, and the temperature probe was placed in the center of the meat patty, and the prawns were processed with a single physical field (140 ℃ steam heating) until the center temperature of the prawn meat reached 70 ℃, wherein the power of the steam heat processing was 1500 W, the operating time was 150 s, the operating temperature was 140 ℃, and the center temperature of the prawn meat increased from 25 ℃ to 70 ℃, thereby obtaining the prawn meat with the first depurination. 0.2 g of the low-purine shrimp sample obtained after the above processing was taken, and 11 mL of mixed acid (according to the volume ratio, trifluoroacetic acid: formic acid: water = 5:5:1) was added to hydrolyze at 90°C for 12 min; the hydrolyzed sample was rotary evaporated at 55°C, and after evaporation to dryness, 10 mL of mobile phase A (pH 3.8 and a mixed solution containing 0.2 mol / L potassium dihydrogen phosphate and 0.52 mmol / L sodium pentane sulfonate, the solvent of the mixed solution was ultrapure water) was added to dissolve purine under ultrasound assistance, and after ultrasound, the sample was centrifuged at 8445 × g at 4°C for 10 min, and the supernatant was filtered through a 0.22 μm aqueous phase filter membrane and analyzed by high performance liquid chromatography to determine the contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content.

[0065] Table 16 Parameters of single physical field combined processing of shrimp

[0066] Comparative Example 13 The sensory evaluation standards for shrimps processed by single physical field, double physical field and triple physical field include the following steps: Eight evaluators with certain professional backgrounds were selected to conduct sensory evaluation on the shrimp processed in the physical field. The evaluation criteria for the food are as follows.

[0067] Table 17 Sensory evaluation standards for shrimp

[0068] Comparative Example 14 The method for releasing purine from shrimp based on the double enzyme method comprises the following steps: Accurately weigh 5 g of minced unprocessed shrimp meat sample into a 50 mL centrifuge tube, add 4 mL SSF1.25× and 1 mL distilled water and place in a 37°C constant temperature shaker. The second stage, gastric digestion for 3 h. Add 8 mL SGF 1.25×, 0.667 mL pepsin solution, and 0.48 mL gastric lipase solution to the oral digestion system, and adjust the pH to 3. The third stage: intestinal digestion for 3 h. Add 8 mL SIF 1.25×, 5 mL trypsin solution, and 3 mL bile salt solution to the gastric digestion system, and adjust the pH to 7. The enzyme activities of pepsin, gastric lipase, and trypsin are 15000, 30000, and 250 U / mg, respectively. The system after in vitro simulated digestion was centrifuged at 8000 g and 4°C for 10 min and the supernatant A was collected. Take part of the supernatant A and mix it with 60% perchloric acid at a ratio of 10:1 v / v (the final concentration of perchloric acid is about 10:1). Then centrifuge at 8000 g and 4°C for 10 min to collect the supernatant B. HPLC is used to determine the purine concentration in the supernatant B. The purine content released into the solution after simulated digestion of the food is obtained by conversion. The degree of purine release can also be further obtained. The specific calculation formula is as follows: W= ×100 (3-1) DR= ×100 (3-2) In formula (3-1), W represents the purine content that can be released into the digestive fluid of shrimp after simulated digestion under the condition of 100 g dry weight, mg / 100g; C B represents the purine concentration in supernatant B, mg / L; V represents the volume of the digestion endpoint solution, 40 mL; m represents the dry weight corresponding to 5 g of sample.

[0069] In formula (3-2), M represents the total amount of purine obtained from shrimps under 100 g dry weight after purine reduction physical field processing. DR represents the secondary release degree of purine, that is, the proportion of free purine that can be released into the digestive fluid of shrimps after simulated digestion to the total amount of purine in the food.

[0070] The contents of four purines (guanine, xanthine, hypoxanthine and adenine) and the total purine content in the shrimp patties obtained in Examples 1-3 of the present invention and Comparative Examples 1-16 were analyzed and compared to obtain Figures 1 to 6 , as shown in the accompanying drawings of the specification; the sensory evaluation of the shrimp patties obtained in Example 4 of the present invention and Comparative Example 17 was Figure 7 , as shown in the accompanying drawings of the specification; the purine release diagram and uric acid generation effect in the second depurinized shrimp meat cake obtained in Examples 5 and 6 of the present invention, Figure 8-9 , as shown in the accompanying drawings of the specification.

[0071] Figure 1The purine content of raw shrimp and shrimp processed by the double physical field combination of upper and lower tube hot air processing + steam heat processing in Example 1-3 is a bar graph. Figure 1 It can be seen that compared with raw shrimp, the hypoxanthine content and total purine content of shrimp patties processed by the dual physical field combination of upper and lower tube hot air processing + steam heat processing in order are significantly reduced, and the total purine content can be reduced by 16.12%-16.85%.

[0072] Figure 2 The purine content of fresh shrimps and shrimps processed by the dual physical field combination of upper and lower tube hot air heating + steam heating and the dual physical field combination of high-intensity microwave + 140°C steam in Example 1 and Comparative Example 1 is shown in the figure. Figure 1 It can be seen that compared with fresh shrimp meat, the hypoxanthine content of shrimp meat processed by the dual physical field combination was significantly reduced (p<0.0001), and the hypoxanthine content of shrimp processed by the upper and lower tube hot air heating + steam heating dual physical field combination and high-intensity microwave + 140℃ steam dual physical field combination was reduced by 53.05% and 46.26% respectively; while the adenine content was significantly increased (p<0.0001), increasing by 32.53% and 61.92% respectively. Comprehensively considering the changes in hypoxanthine and adenine content, the total purine content of shrimp processed by the lower tube hot air heating + steam heating dual physical field combination and high-intensity microwave + 140℃ steam dual physical field combination was significantly reduced (p<0.05), decreasing by 16.23% and 10.81% respectively.

[0073] Figure 3 This is a bar graph of the purine content of shrimp after three physical field processing (Comparative Example 2, Comparative Example 3). Figure 3 It can be seen that compared with unprocessed shrimp meat, the hypoxanthine content of the shrimp processed by 140℃ upper and lower tube hot air + high-intensity microwave + 140℃ steam, high-intensity microwave + 140℃ upper and lower tube hot air + 140℃ steam was significantly reduced ( p<0.0001 ), decreased by 12.35% and 62.18% respectively, while the adenine content increased significantly ( p<0.0001 ), increased by 13.15% and 88.18% respectively. The above two changes in purine caused the total purine content to have a downward trend, but the statistics were not significant ( p>0.05 ).

[0074] Figure 4 The following is a bar graph showing the purine content of shrimps processed by upper and lower tube hot air physical fields (Comparative Example 4, Comparative Example 5, Comparative Example 6). Figure 4 It can be seen that compared with unprocessed shrimp meat, the physical field processing of upper and lower tube hot air at 100℃, 120℃, and 140℃ can significantly reduce the guanine and adenine contents in the shrimp (p<0.01), while the hypoxanthine content is significantly increased ( p<0.001). Compared with unprocessed shrimp meat, the total purine content of shrimp meat processed by 100℃ hot air physical field was not significantly different from that of unprocessed shrimp meat ( p >0.05), the total purine content of the upper and lower tube hot air heating physical field processing at 120℃ and 140℃ was significantly reduced ( p <0.05), decreased by 4.31%, 8.10% and 9.65% respectively.

[0075] Figure 5 This is a bar chart of the purine content of shrimp processed by microwave physical field (Comparative Example 4, Comparative Example 5, Comparative Example 6). Figure 5 As shown in the figure, compared with the unprocessed shrimp, high-intensity microwave physical field processing had no significant effect on the contents of guanine, adenine and hypoxanthine ( p >0.05); low-intensity microwave physical field processing can significantly increase the hypoxanthine and guanine contents in shrimp meat ( p <0.05), while reducing adenine content ( p <0.01); In addition, medium-intensity microwave physical field treatment can significantly increase the hypoxanthine and guanine contents of shrimp meat ( p <0.05); In summary, except for the obvious effect of low-intensity microwave physical field on the total purine content ( p <0.001), and medium-intensity and high-intensity microwave physical field treatments had no significant effect on the total purine content ( p> 0.05 ).

[0076] Figure 6 The effect of steam physical field on the purine content of shrimps was investigated. The three different temperatures of steam physical field treatment significantly reduced the adenine content of shrimps. p <0.001), while the 100℃ and 120℃ steam physical field treatments significantly increased the hypoxanthine content (p<0.001), increasing by 36.69% and 12.26% respectively, but the 140℃ treatment had no significant effect on the hypoxanthine content of the shrimp ( p >0.05); In addition, compared with unprocessed shrimp meat, 100℃ steam physical field treatment had no significant effect on the total purine content of shrimp ( p >0.05, while the 120℃ and 140℃ treatments significantly reduced the total purine content of shrimp ( p <0.001), which were reduced by 14.35% and 15.50%, respectively.

[0077] Figure 7It is a sensory evaluation diagram of the shrimp after being processed by different physical fields (Example 2, Comparative Example 13). It can be seen from the figure that the sensory characteristics of the shrimp after being processed by the physical field are good. The sensory characteristics of the shrimp after being processed by the single physical field of steam are slightly better than those of other physical fields. For the microwave physical field, the higher the microwave intensity, the better the shrimp meat, taste, flavor, tissue state, and color after the corresponding processing. For the shrimp after being processed by the dual physical field of upper and lower tube hot air heating + steam heating, the scores of various sensory indicators are also similar to those of the single physical field of steam, indicating that the upper and lower tube hot air heating + steam heating is suitable for the processing of low-purine shrimp products.

[0078] Figure 8 This is a graph of the purine content of the shrimp after the double physical field processing and double enzyme digestion. Compared with the undigested group, the guanine and adenine content released into the digestive fluid after simulated digestion in the unprocessed group and the double physical field processing group was significantly reduced ( p <0.05), while hypoxanthine showed an increasing trend, indicating that in addition to the release of hypoxanthine, other purines were converted into hypoxanthine during digestion. In addition, compared with the unprocessed group, the release of adenine and guanine in the dual physical field processed group increased significantly ( p <0.05), hypoxanthine release was significantly reduced ( p <0.01, but because the release of hypoxanthine is significantly higher than the sum of the first two, the total purine release from food is reduced ( p <0.01). The total purine release in the dual physical field processing group (46.54%) was significantly lower than that in the unprocessed group (64.64%) ( p <0.01), indicating that the amount of uric acid produced by the shrimp processed by the purine-reducing physical field after digestion may be reduced. Example 6 and Example 7 also have the same effect.

[0079] Fig. 9 This is the effect of dual physical field processing on the uric acid production of shrimp after dual enzyme digestion. After the shrimp was processed by dual physical field and then digested by dual enzymes, an experiment on the uric acid production in vitro was conducted. As shown in the figure, the uric acid production in the digestive fluid of shrimp in the dual physical field processing group was significantly lower than that in the unprocessed group, further proving that dual physical field processing combined with dual enzyme digestion of shrimp is an effective depurination method.

Claims

1. A method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion, characterized in that: The steps include: (1) removing the shrimp threads from fresh shrimps, and then absorbing moisture from the surface of the shrimps to obtain shrimp meat to be heat-processed; (2) placing the shrimp to be heat-processed in step (1) in a microwave oven, placing a temperature probe in the center of the shrimp meat, and setting a hot air upper and lower pipe heating program to run; (3) After the hot air upper and lower tube heating processing program is run, the program of the microwave steamer and oven is set to the high-temperature steam heating program to obtain depurinated shrimp patties; (4) The shrimp meat that has undergone the first depurination is subjected to a simulated digestion process to obtain shrimp meat in which purine is released for a second time.

2. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 1, characterized in that: The power of the hot air upper and lower pipe heating program in step (2) is 1450 - 1650 W.

3. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 2, characterized in that: The hot air upper and lower pipe heating program in step (2) runs for 170-190 seconds.

4. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 1, characterized in that: The temperature setting value of the hot air upper and lower pipe heating program in step (2) is 130 - 150 °C.

5. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 4, characterized in that: When the hot air upper and lower pipe heating program in step (2) is running, the center temperature of the meat patty rises from 20-25°C to 40-45°C.

6. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 1, characterized in that: The power setting value of the steam heating program in step (3) is 1400-1600 W.

7. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 6, characterized in that: The steam heating program in step (3) runs for 50-70 seconds, and the steam heating program in step (3) runs at a temperature of 138-142°C.

8. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 1, characterized in that: When the steam heating program in step (3) is running, the center temperature of the shrimp meat rises from 40-45°C to 65-70°C.

9. The method for depurinating shrimp based on dual physical field thermal processing and dual enzyme simulated digestion according to claim 1, characterized in that: During the in vitro simulated digestion in step (4), the digestive enzymes are pepsin and trypsin, the pepsin digestion time is 40-50 min, and the trypsin digestion time is 140-160 min.

10. The shrimp prepared by the shrimp depurination method based on dual physical field thermal processing and dual enzyme simulated digestion as described in any one of claims 1 to 9.

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