Preparation method of salmon roe composite extract

Abstract

The invention belongs to the technical field of biological medicines, and relates to a preparation method of a salmon roe composite extract, which comprises the following steps: (1) raw material pretreatment; (2) ultrasonic-pulsed electric field combined wall breaking; (3) directional hydrolysis with a compound enzyme; (4) combining aqueous two-phase extraction with ultrafiltration concentration; and (5) freeze-drying and forming. The salmon roe composite extract which is loose, easy to store and high in purity is prepared, the whole process is low in temperature and free of strong chemical reagent treatment, protein activity, unsaturated fatty acid integrity and heat-sensitive components such as vitamins are reserved to the maximum extent, and the product is high in biological activity; the salmon roe nutritional ingredient extraction method has the advantages that the salmon roe nutritional ingredient extraction rate is increased evidently by the aid of ultrasonic-pulsed electric field synergistic wall breaking, compound enzyme precise matching directional hydrolysis and two-aqueous-phase ultrafiltration combined innovative processes, efficient extraction is realized, operation is controllable, equipment universality is high, and industrial large-scale production is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedicine and relates to a method for preparing a salmon roe composite extract. Background Art

[0002] Salmon roe is rich in nutrients such as protein, unsaturated fatty acids (such as EPA, DHA), phospholipids, vitamins and various minerals, and has extremely high nutritional value and health benefits.

[0003] The salmon roe compound extract is rich in high-quality protein and bioactive peptides, which can be quickly absorbed by the human body and can be used as the core raw material of sports nutrition food. After high-intensity training, athletes' muscles are damaged and their physical energy is greatly consumed. The active peptides in the extract help muscle repair, reduce fatigue, and accelerate physical recovery. The phospholipids and unsaturated fatty acids in the salmon roe compound extract are natural moisturizing and skin repair factors. In high-end creams and essences, phospholipids form a lipid bilayer structure, simulate the skin's natural barrier, firmly lock in skin moisture, and enhance the skin's moisturizing ability.

[0004] Salmon roe extract is pure and highly biocompatible, and can be used as a sustained-release drug carrier in the medical field. Its special molecular structure is used to encapsulate drug molecules, achieve slow and precise drug release, prolong drug efficacy, and reduce drug toxicity and side effects; in wound dressings, the antibacterial and anti-inflammatory components of the extract inhibit the growth of wound bacteria, and proteins and active peptides promote cell proliferation and tissue repair, accelerate wound healing, reduce scar formation, improve patient healing comfort, and help upgrade the quality of medical consumables.

[0005] Traditional salmon roe processing focuses on caviar production, and a large number of supplementary nutrients are not fully utilized; the existing salmon roe extract preparation methods have complex processes, low extraction efficiency, large nutrient loss, poor product purity, or the introduction of chemical reagent residues that affect quality and safety. Therefore, it is of great practical significance to develop an efficient, green, and innovative preparation process for salmon roe composite extracts. Summary of the invention

[0006] In view of the deficiencies of the above-mentioned prior art, the present invention provides a method for preparing a salmon roe composite extract, and the specific technical scheme is as follows: A method for preparing a salmon roe composite extract comprises the following steps: (1) Raw material pretreatment: Select frozen salmon roe with ovarian membrane, thaw them gradually, wash them with physiological saline, and then soak them in a mixed aqueous solution of vitamin C and chitosan for 30 to 45 minutes for antioxidant and antibacterial treatment, then remove them and drain them for later use; (2) Combined cell wall breaking by ultrasound and pulsed electric field: The pretreated salmon roe was subjected to ultrasonic treatment for 10 to 15 minutes, followed by pulsed electric field treatment for 5 to 8 minutes for combined cell wall breaking; (3) Complex enzyme directional hydrolysis: add phosphate buffer to the salmon roe after the cell wall breaking treatment, and then add trypsin, papain and flavor protease in sequence, and hydrolyze for 3-4 hours at 45-50°C and stirring speed of 180-220 r / min to obtain the hydrolyzate; (4) Two-phase aqueous extraction combined with ultrafiltration concentration: A two-phase aqueous system consisting of polyethylene glycol and potassium phosphate or ammonium sulfate is added to the hydrolyzate, stirred evenly, and then allowed to stand for 20 to 30 minutes to separate into layers. The upper phase solution is taken and concentrated by ultrafiltration through an ultrafiltration membrane to remove small molecular impurities and excess water to obtain a preliminary concentrated composite extract; (5) Freeze-drying: The preliminary concentrated composite extract is pre-frozen at -50 to -40°C for 3 to 4 hours, and then vacuum freeze-dried to obtain the salmon roe composite extract powder.

[0007] The preparation method of the salmon roe composite extract of the present invention comprises the following steps: in step (1), gradient thawing is used to make the salmon roe intact and fresh-keeping, vitamin C in the mixed aqueous solution inhibits lipid oxidation in the salmon roe, and chitosan constructs a physical antibacterial barrier to synergistically protect color and preserve freshness; in step (2), ultrasonic treatment is used to initially loosen the salmon roe cells, ultrasonic cavitation and the electroporation effect of the pulsed electric field synergistically act to efficiently break the salmon roe cell wall and cell membrane, and release intracellular substances. Compared with traditional mechanical crushing, the cell wall breaking is more thorough and the energy consumption is low; in step (3), multiple enzymes of the composite enzyme (trypsin, papain and flavor protease) act synergistically to accurately cut proteins into small molecular active peptides, retain biological activity, and improve hydrolysis efficiency. The invention relates to a novel method for preparing the salmon roe composite extract and a novel method for preparing the salmon roe composite extract. The invention relates to a ... and a novel method for preparing the salmon roe composite extract. The invention relates to a method for preparing the salmon roe composite extract and a novel method for preparing the salmon roe composite extract and a novel method for preparing the salmon roe composite extract and a novel method for preparing the salmon roe composite extract and a novel method for preparing the salmon

[0008] Furthermore, in the step (1), after the salmon roe is gradiently thawed, it is washed 2 to 3 times with physiological saline at 35 to 45° C. to remove surface impurities and mucus, and then rinsed with 0.8 to 1 wt % sterile saline.

[0009] Furthermore, in the step (1), a multi-stage countercurrent cleaning method is adopted during the washing of salmon roe with physiological saline.

[0010] Pass the salmon roe through multiple cleaning tanks in turn, with the water flowing in the opposite direction of the movement of the salmon roe. This can more effectively remove impurities, mucus and blood on the surface of the salmon roe.

[0011] Furthermore, in step (1), the mixed aqueous solution of vitamin C and chitosan contains 0.3-0.5 wt % of vitamin C and 0.2-0.3 wt % of chitosan.

[0012] Furthermore, in step (2), the frequency of the ultrasonic treatment is 20-30 kHz, the power is 300-400 W, the electric field intensity of the pulse electric field treatment is 20-30 kV / cm, the pulse width is 20-30 μs, and the pulse frequency is 500-800 Hz.

[0013] Furthermore, in step (3), the pH of the phosphate buffer is 7-8, and the amount added is 1.5-2 times the mass of the salmon roe; the amount of trypsin added is 0.4-0.6% of the mass of the salmon roe, the amount of papain added is 0.3-0.4% of the mass of the salmon roe, and the amount of flavor protease added is 0.2-0.3% of the mass of the salmon roe.

[0014] The invention adopts papain, trypsin and flavor protease in combination and controls the ratio, dosage, enzymolysis time, enzymolysis temperature and stirring speed of the enzymes, so that the enzymes are fully in contact with the substrates, the advantages of each enzyme are fully utilized, the enzymolysis efficiency is improved, and the length of the peptide chain is effectively controlled; papain is used as a main hydrolase to firstly perform large-area preliminary hydrolysis on salmon roe protein to provide a basis for subsequent enzymatic cutting; trypsin is followed up in a suitable ratio to perform cutting on specific positions of the preliminary hydrolysis product to produce more types of small peptides; and the flavor protease is finally used to process the end of the peptide chain, which not only refines the polypeptide but also improves the flavor.

[0015] Furthermore, in the step (4), the mass ratio of polyethylene glycol to potassium phosphate is (1.5-2):1, the molecular weight cutoff of the ultrafiltration membrane is 10 kDa, and the target molecular weight is further purified.

[0016] Furthermore, in the step (4), the polyethylene glycol is PEG4000, PEG6000 or PEG8000, preferably PEG4000.

[0017] Furthermore, in step (5), the vacuum degree of the vacuum freeze-drying is 10-30 Pa, the temperature is -30--20°C, and the time is 12-20 hours.

[0018] Furthermore, in the step (1), frozen salmon roe with ovarian membranes of good freshness and integrity are selected, and salmon roe with poor color or size that does not meet the requirements are removed through a high-resolution camera and image recognition software, such as the diameter of red salmon roe is 6-7 mm, and the diameter of pink salmon roe is 4-5 mm.

[0019] When selecting salmon roe, in addition to considering the freshness and integrity of the salmon roe, optical sorting technology can also be used to more accurately screen out high-quality salmon roe based on the color, size and other characteristics of the salmon roe. Salmon roe with poor color may indicate that the nutrients are damaged, and salmon roe that do not meet the size requirements may affect the uniformity of subsequent processing.

[0020] Furthermore, in the step (4), in the ultrafiltration concentration step using an ultrafiltration membrane, a multi-stage ultrafiltration system is used, first using an ultrafiltration membrane with a molecular weight cutoff of 10-20 kDa, and then using an ultrafiltration membrane with a molecular weight cutoff of 5-10 kDa.

[0021] According to the molecular weight distribution of the target extract, ultrafiltration membranes with different molecular weight cutoffs are set to gradually remove small molecular impurities and excess water, thereby improving the concentration efficiency and extract purity.

[0022] The beneficial effects of the present invention are: The method for preparing the salmon roe composite extract provided by the present invention overcomes the defects of the prior art, retains the nutritional components of salmon roe to the greatest extent, achieves efficient extraction, obtains high-purity and multifunctional composite extracts, meets the raw material needs of multiple fields such as food, health products, and cosmetics, and expands the salmon roe deep processing industry chain.

[0023] The present invention uses low temperature and no strong chemical reagent treatment throughout the process, which retains the protein activity, unsaturated fatty acid integrity and heat-sensitive components such as vitamins to the greatest extent, and the product has high biological activity. Through the innovative process of ultrasound-pulse electric field synergistic combined wall breaking, complex enzyme precise matching directional hydrolysis, and two-phase aqueous ultrafiltration, the extraction rate of salmon roe nutrients is significantly improved, and the operation is controllable, the equipment has strong versatility, and it is easy to scale up industrial production. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below in conjunction with embodiments. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention.

[0025] Embodiment 1: A method for preparing a salmon roe composite extract comprises the following steps: (1) Raw material pretreatment: 10 kg of frozen, fresh and intact salmon roe with ovarian membranes were selected and gradient thawed at -10°C / 2h~-4°C / 2h~4°C / 10h. After gradient thawing, the roe was washed three times with physiological saline at 40°C in a countercurrent washing manner with the water flow direction opposite to the movement direction of the salmon roe to remove surface impurities and mucus, and obtain plump and round salmon roe particles; after being taken out, the roe was rinsed with 1wt% sterile saline, and then immersed in a mixed aqueous solution containing 0.4wt% vitamin C and 0.3wt% chitosan for 35 minutes for antioxidant and antibacterial treatment, and then taken out and drained for later use; (2) Combined cell wall breaking by ultrasound and pulsed electric field: The pretreated salmon eggs were placed in a reaction container and first subjected to ultrasonic treatment at a frequency of 25 kHz and a power of 350 W for 12 minutes to initially loosen the salmon egg cells; then the cells were switched to a pulsed electric field with an electric field strength of 25 kV / cm, a pulse width of 25 μs, and a pulse frequency of 600 Hz for 6 minutes for combined cell wall breaking treatment; (3) Composite enzyme directional hydrolysis: 18 kg of pH 7 phosphate buffer was added to the salmon roe material after the combined cell wall breaking treatment, and 50 g of trypsin, 35 g of papain, and 25 g of flavor protease were added in sequence. The mixture was hydrolyzed at 48 ° C and a stirring speed of 200 r / min for 3.5 hours to obtain a hydrolyzate; (4) Two-phase aqueous extraction combined with ultrafiltration concentration: The hydrolyzate was added to 10 L of a two-phase aqueous system consisting of polyethylene glycol (PEG4000) and potassium phosphate in a mass ratio of 1.8:1. After stirring evenly, the mixture was allowed to stand for 25 minutes to separate into layers. The target extract was concentrated in the upper phase. The upper phase solution was concentrated by ultrafiltration through an ultrafiltration membrane with a molecular weight cutoff of 10 kDa to remove small molecular impurities and excess water, thereby obtaining a preliminary concentrated composite extract. (5) Freeze-drying: The preliminary concentrated composite extract was pre-frozen at -45°C for 3.5 hours, and then placed in a vacuum freeze dryer at a vacuum degree of 20 Pa and a temperature of -25°C for 16 hours to obtain the salmon roe composite extract powder.

[0026] Embodiment 2: A method for preparing a salmon roe composite extract comprises the following steps: (1) Raw material pretreatment: 1 kg of frozen, fresh and intact salmon roe with ovarian membranes was selected, and gradient thawing was performed at -10°C / 2h~-4°C / 2h~4°C / 10h. After gradient thawing, the roe was washed three times with physiological saline at 40°C in a countercurrent washing manner with the water flow direction opposite to the movement direction of the salmon roe to remove surface impurities and mucus, and obtain plump and round salmon roe particles; after being taken out, the roe was rinsed with 1wt% sterile saline, and then immersed in a mixed aqueous solution containing 0.4wt% vitamin C and 0.3wt% chitosan for 35 minutes for antioxidant and antibacterial treatment, and then taken out and drained for later use; (2) Combined cell wall breaking by ultrasound and pulsed electric field: The pretreated salmon eggs were placed in a reaction container and first subjected to ultrasonic treatment at a frequency of 20 kHz and a power of 300 W for 10 minutes to initially loosen the salmon egg cells; then the cells were switched to a pulsed electric field with an electric field strength of 20 kV / cm, a pulse width of 20 μs, and a pulse frequency of 500 Hz for 5 minutes to perform a combined cell wall breaking treatment; (3) Composite enzyme directional hydrolysis: 1.5 kg of pH 7 phosphate buffer was added to the salmon roe material after the combined cell wall breaking treatment, and 4 g of trypsin, 3 g of papain, and 3 g of flavor protease were added in sequence. The mixture was hydrolyzed at 45° C. and a stirring speed of 180 r / min for 3 hours to obtain a hydrolyzate; (4) Two-phase aqueous extraction combined with ultrafiltration concentration: The hydrolyzate was added to 1 L of a two-phase aqueous system consisting of polyethylene glycol (PEG4000) and potassium phosphate in a mass ratio of 1.5:1, stirred evenly and allowed to stand for 25 minutes to separate into layers. The target extract was enriched in the upper phase. The upper phase solution was concentrated by ultrafiltration through an ultrafiltration membrane with a molecular weight cutoff of 10 kDa to remove small molecular impurities and excess water to obtain a preliminary concentrated composite extract. (5) Freeze-drying: The preliminary concentrated composite extract was pre-frozen at -40°C for 3 hours, and then placed in a vacuum freeze dryer at a vacuum degree of 20 Pa and a temperature of -25°C for 12 hours to obtain the salmon roe composite extract powder.

[0027] Comparative Example 1: A method for preparing a salmon roe composite extract comprises the following steps: (1) Raw material pretreatment: 10 kg of frozen, fresh and intact salmon roe with ovarian membranes were selected and gradient thawed at -10°C / 2h~-4°C / 2h~4°C / 10h. After gradient thawing, the roe was washed three times with physiological saline at 40°C in a countercurrent washing manner with the water flow direction opposite to the movement direction of the salmon roe to remove surface impurities and mucus, and obtain plump and round salmon roe particles; after being taken out, the roe was rinsed with 1wt% sterile saline, and then immersed in a mixed aqueous solution containing 0.4wt% vitamin C and 0.3wt% chitosan for 35 minutes for antioxidant and antibacterial treatment, and then taken out and drained for later use; (2) Combined cell wall breaking by ultrasound and pulsed electric field: The pretreated salmon eggs were placed in a reaction container and first subjected to ultrasonic treatment at a frequency of 25 kHz and a power of 350 W for 12 minutes to initially loosen the salmon egg cells; then the cells were switched to a pulsed electric field with an electric field strength of 25 kV / cm, a pulse width of 25 μs, and a pulse frequency of 600 Hz for 5 minutes to perform a combined cell wall breaking treatment; (3) Enzymatic hydrolysis: 15 kg of pH 7 phosphate buffer and 100 g of trypsin were added to the salmon roe material after cell wall breaking, and hydrolyzed at 48° C. and a stirring speed of 200 r / min for 3.5 hours to obtain a hydrolyzate; (4) Two-phase aqueous extraction combined with ultrafiltration concentration: The hydrolyzate was added to 10 L of a two-phase aqueous system consisting of polyethylene glycol (PEG4000) and potassium phosphate in a mass ratio of 1.8:1. After stirring evenly, the mixture was allowed to stand for 25 minutes to separate into layers. The target extract was concentrated in the upper phase. The upper phase solution was concentrated by ultrafiltration with an ultrafiltration membrane with a molecular weight cutoff of 10 kDa to remove small molecular impurities and excess water, thereby obtaining a preliminary concentrated composite extract. (5) Freeze-drying: The preliminary concentrated composite extract was pre-frozen at -45°C for 3.5 hours, and then placed in a vacuum freeze dryer at a vacuum degree of 20 Pa and a temperature of -25°C for 16 hours to obtain the salmon roe composite extract powder.

[0028] Comparative Example 2 A method for preparing a salmon roe composite extract comprises the following steps: (1) Raw material pretreatment: 10 kg of frozen, fresh and intact salmon roe with ovarian membranes were selected and gradient thawed at -10°C / 2h~-4°C / 2h~4°C / 10h. After gradient thawing, the roe was washed three times with physiological saline at 40°C in a countercurrent washing manner with the water flow direction opposite to the movement direction of the salmon roe to remove surface impurities and mucus, and obtain plump and round salmon roe particles; after being taken out, the roe was rinsed with 1wt% sterile saline, and then immersed in a mixed aqueous solution containing 0.4wt% vitamin C and 0.3wt% chitosan for 35 minutes for antioxidant and antibacterial treatment, and then taken out and drained for later use; (2) Cell wall breaking treatment: The pre-treated salmon eggs were subjected to cell wall breaking treatment in a high-speed homogenizer for 10 min; (3) Composite enzyme directional hydrolysis: add 18 kg of pH 7 phosphate buffer to the salmon roe material after cell wall breaking, add 50 g of trypsin, 35 g of papain, and 25 g of flavor protease in sequence, and hydrolyze at 48°C and stirring speed of 200 r / min for 3.5 hours to obtain a hydrolyzate; (4) Two-phase aqueous extraction combined with ultrafiltration concentration: The hydrolyzate was added to 10 L of a two-phase aqueous system consisting of polyethylene glycol (PEG4000) and potassium phosphate in a mass ratio of 1.8:1. After stirring evenly, the mixture was allowed to stand for 25 minutes to separate into layers. The target extract was concentrated in the upper phase. The upper phase solution was concentrated by ultrafiltration through an ultrafiltration membrane with a molecular weight cutoff of 10 kDa to remove small molecular impurities and excess water, thereby obtaining a preliminary concentrated composite extract. (5) Freeze-drying: The preliminary concentrated composite extract was pre-frozen at -45°C for 3.5 hours, and then placed in a vacuum freeze dryer at a vacuum degree of 20 Pa and a temperature of -25°C for 16 hours to obtain the salmon roe composite extract powder.

[0029] Test experiment 1. Comparison of wall-breaking effects The cell wall breaking of salmon eggs in the embodiment and the comparative example was observed under a microscope, and the percentage of intact cells was counted. The results are shown in Table 1: Table 1 Comparison of wall-breaking effects in the examples and comparative examples

[0030] Examples 1 and 2 use ultrasound-pulse electric field combined wall breaking, and the proportion of intact cells is extremely low, indicating that the wall breaking effect is significant and the intracellular substances can be fully released; although Comparative Example 1 uses some advanced wall breaking methods, the subsequent hydrolysis step is changed, which affects the feedback of the early wall breaking effect, and there are still many intact cells, proving that the combined wall breaking technology has obvious advantages; Comparative Example 2 uses traditional mechanical wall breaking, and due to problems such as uneven mechanical shear force, a large number of cells are not effectively broken.

[0031] 2. Comparison of hydrolysis degree High performance liquid chromatography (HPLC) was used to measure the proportion of small molecular active peptides with a molecular weight less than 10 kDa in the hydrolyzates of the examples and comparative examples. The results are shown in Table 2: Table 2 Comparison of hydrolysis degree in Examples and Comparative Examples

[0032] In Examples 1 and 2, multiple enzymes cooperate to precisely cut proteins through composite enzyme directional hydrolysis to generate a large number of small molecule active peptides; in Comparative Example 1, single enzyme hydrolysis lacks the synergistic effect of multiple enzymes and cannot efficiently and precisely cut proteins, resulting in the production of small molecule active peptides far lower than in the examples, highlighting the superiority of composite enzyme hydrolysis; in Comparative Example 2, the cell wall is not completely broken, which affects the contact between the enzyme and the substrate, and the degree of hydrolysis is limited.

[0033] 3. Extract purity comparison The impurity content in the extracts of the examples and comparative examples was measured by gel filtration chromatography, and the purity of the extracts was calculated. The results are shown in Table 3: Table 3 Comparison of the purity of the extracts in the examples and comparative examples

[0034] The embodiment adopts two-phase aqueous extraction combined with ultrafiltration concentration, and utilizes the selective distribution of two-phase aqueous solution and the precise separation characteristics of ultrafiltration to effectively remove small molecule impurities and excess water, thereby greatly improving the purity of the extract; the comparative example has more impurities introduced due to poor initial wall breaking and hydrolysis effects, and the subsequent separation means cannot fully make up for the initial defects, and the purity is significantly lower than that of the embodiment.

[0035] In summary, the method for preparing the salmon roe composite extract provided by the present invention performs better than the traditional process in terms of wall breaking effect, hydrolysis degree and extract purity, and has broad application prospects and industrial value.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a salmon roe composite extract, characterized in that: The steps include: (1) Raw material pretreatment: Select frozen salmon roe with ovarian membrane, thaw them gradually, wash them with physiological saline, and then soak them in a mixed aqueous solution of vitamin C and chitosan for 30 to 45 minutes for antioxidant and antibacterial treatment, then remove them and drain them for later use; (2) Combined cell wall breaking by ultrasound and pulsed electric field: The pretreated salmon roe was subjected to ultrasonic treatment for 10 to 15 minutes, followed by pulsed electric field treatment for 5 to 8 minutes for combined cell wall breaking; (3) Complex enzyme directional hydrolysis: add phosphate buffer to the salmon roe after the cell wall breaking treatment, and then add trypsin, papain and flavor protease in sequence, and hydrolyze for 3-4 hours at 45-50°C and stirring speed of 180-220 r / min to obtain the hydrolyzate; (4) Two-phase aqueous extraction combined with ultrafiltration concentration: A two-phase aqueous system consisting of polyethylene glycol and potassium phosphate or ammonium sulfate is added to the hydrolyzate, stirred evenly, and then allowed to stand for 20 to 30 minutes to separate into layers. The upper phase solution is taken and concentrated by ultrafiltration through an ultrafiltration membrane to remove small molecular impurities and excess water to obtain a preliminary concentrated composite extract; (5) Freeze-drying: The preliminary concentrated composite extract is pre-frozen at -50 to -40°C for 3 to 4 hours, and then vacuum freeze-dried to obtain the salmon roe composite extract powder.

2. The method for preparing the salmon roe composite extract according to claim 1, characterized in that: In the step (1), after the salmon roe is gradiently thawed, it is washed 2 to 3 times with physiological saline at 35 to 45° C. to remove surface impurities and mucus, and then rinsed with 0.8 to 1 wt % sterile saline.

3. The method for preparing the salmon roe composite extract according to claim 2, characterized in that: In the step (1), the mixed aqueous solution of vitamin C and chitosan contains 0.3-0.5 wt % of vitamin C and 0.2-0.3 wt % of chitosan.

4. The method for preparing the salmon roe composite extract according to claim 1, characterized in that: In the step (2), the frequency of ultrasonic treatment is 20-30 kHz, and the power is 300-400 W.

5. The method for preparing the salmon roe composite extract according to claim 4, characterized in that: In the step (2), the electric field intensity of the pulse electric field treatment is 20-30 kV / cm, the pulse width is 20-30 μs, and the pulse frequency is 500-800 Hz.

6. The method for preparing the salmon roe composite extract according to claim 1, characterized in that: In the step (3), the pH of the phosphate buffer is 7-8, and the amount added is 1.5-2 times the mass of the salmon roe.

7. The method for preparing the salmon roe composite extract according to claim 6, characterized in that: In the step (3), the amount of trypsin added is 0.4-0.6% of the mass of the salmon roe, the amount of papain added is 0.3-0.4% of the mass of the salmon roe, and the amount of flavor protease added is 0.2-0.3% of the mass of the salmon roe.

8. The method for preparing the salmon roe composite extract according to claim 1, characterized in that: In the step (4), the mass ratio of the polyethylene glycol to potassium phosphate is (1.5-2):

1.

9. The method for preparing the salmon roe composite extract according to claim 8, characterized in that: In the step (4), the molecular weight cut-off of the ultrafiltration membrane is 10 kDa.

10. The method for preparing the salmon roe composite extract according to claim 1, characterized in that: In the step (5), the vacuum degree of the vacuum freeze drying is 10-30 Pa, the temperature is -30-20° C., and the time is 12-20 hours.

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