Preparation method of egg yolk phospholipid polypeptide powder and application of egg yolk phospholipid polypeptide powder in blood fat regulation

Abstract

The invention discloses a preparation method of egg yolk phospholipid polypeptide powder and application of the egg yolk phospholipid polypeptide powder in blood fat regulation. The preparation method comprises the following steps: (1) carrying out enzymolysis treatment; (2) deslagging and separating; (3) ultrasonic enzymolysis; (4) thermal reaction treatment; (5) performing pasteurization; (6) low-temperature spray drying; and (7) deoiling and crushing treatment: performing powder granulation on the dried egg yolk zymolyte in the step (6), performing supercritical carbon dioxide deoiling, and performing crushing treatment to obtain the egg yolk phospholipid polypeptide powder. Compared with egg yolk phospholipid, the egg yolk phospholipid polypeptide prepared by the invention has good dissolution dispersibility and oxidation stability.

Description

Technical Field

[0001] The invention relates to the field of functional food raw materials, and in particular to a preparation method of egg yolk phospholipid polypeptide powder and application of the powder in blood lipid regulation. Background Art

[0002] Egg yolk lecithin is a phospholipid mixture mainly composed of phosphatidylcholine, usually in the form of a light yellow waxy solid or paste. It has significant effects on regulating blood lipids, softening blood vessels, and preventing cardiovascular diseases such as arteriosclerosis, myocardial infarction and cerebral hemorrhage. When egg yolk lecithin is used as a functional food raw material, its application in special dietary foods, health foods, biomedicine and other fields is greatly limited due to problems such as easy oxidation and poor solubility and dispersion. According to the information recently released by the National Health Commission's government service platform, the newly added egg yolk phospholipid protein (named "egg yolk lecithin" when accepted) in the "Catalogue of New Food Raw Materials for Termination of Review" in the Food Regulation Inspection can be used as a food raw material, and the food safety indicators are implemented in accordance with the ready-to-eat egg products in my country's national food safety standards.

[0003] Egg yolk phospholipid protein is a food raw material rich in egg yolk phospholipids, which is made from egg yolk powder through granulation, supercritical CO2 extraction, separation and other processes. The main components are protein (≥40.0g / 100g) and phospholipids (≥24.0g / 100g). Patent CN 116268409 A "Application of Egg Yolk Lecithin in Assisting the Lowering of Serum Triglycerides" applied by the initiator of the new food raw material egg yolk phospholipid protein discloses an egg yolk phospholipid product (phospholipid mass percentage greater than 24.2%) obtained by granulation and supercritical CO2 extraction with egg yolk powder as raw material. The product has a good effect in assisting the lowering of blood lipids. However, the egg yolk phospholipid-rich product obtained after supercritical CO2 extraction contains a large amount of insoluble egg yolk protein, which is not conducive to its effective dissolution and dispersion, which not only affects the sensory experience and stability of the product, but also greatly limits its wide application in solid beverages, special dietary foods and other food fields that require good solubility. Summary of the invention

[0004] [Technical issues]

[0005] The purpose of the present invention is to provide an egg yolk phospholipid polypeptide powder and application thereof in blood lipid regulation, so as to solve the problem of insufficient solubility of egg yolk phospholipid protein, a current new food raw material.

[0006] [Technical solution]

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] The first object of the present invention is to provide a method for preparing egg yolk phospholipid polypeptide powder, comprising the following steps:

[0009] (1) Enzymatic hydrolysis: Mix the egg yolk liquid with water, then add the complex enzyme and perform enzymatic hydrolysis at 40-50°C for 3-8 hours;

[0010] (2) slag separation: filtering the egg yolk solution after enzymatic hydrolysis in step (1) to separate the soluble enzymatic hydrolyzate and the insoluble matter;

[0011] (3) Ultrasonic enzymatic hydrolysis: the insoluble matter obtained in step (2) is dispersed in purified water, and then alkaline protease is added, and ultrasonic enzymatic hydrolysis is performed at 45-55° C. for 2-4 hours to obtain a soluble enzymatic hydrolyzate;

[0012] (4) thermal reaction treatment: adding polydextrose, inulin or oligofructose to the soluble enzymatic hydrolysate obtained in step (3) and inducing the reaction at 55-75° C. for 0.5-2 h;

[0013] (5) pasteurization: combining the soluble enzymatic hydrolysate from step (2) and the soluble enzymatic hydrolysate treated in step (4) and then performing pasteurization;

[0014] (6) low temperature spray drying: subjecting the pasteurized enzymatic hydrolysate in step (5) to low temperature spray drying;

[0015] (7) De-oiling and pulverizing: the egg yolk hydrolysate dried in step (6) is powdered and granulated, then de-oiled with supercritical carbon dioxide, and pulverized to obtain the egg yolk phospholipid polypeptide powder.

[0016] In one embodiment of the present invention, in step (1), the mass ratio of egg yolk liquid to water is 1:0.5-2;

[0017] In one embodiment of the present invention, in step (1), the complex enzyme is a mixture of neutral protease and papain; the enzyme activity ratio of neutral protease to papain is 2:1, and the added amount of the complex enzyme is 4000U / g protein-8000U / g protein.

[0018] In one embodiment of the present invention, in step (1), the protein content is measured and then the complex enzyme is added in proportion.

[0019] In one embodiment of the present invention, in step (1), the plate is preheated to the enzymolysis temperature and pumped into the enzymolysis tank for enzymolysis reaction.

[0020] In one embodiment of the present invention, in step (2), filtration is performed using an automatic slag discharge precision filter with a working pressure of 0.1-0.3 MPa and a filtration accuracy of 1-10 μm.

[0021] In one embodiment of the present invention, in step (3), the mass ratio of insoluble matter to water is 1:5-15; the enzymatic hydrolysis conditions are: enzymatic hydrolysis pH 8-10, alkaline protease addition amount 3000-6000U / g protein, ultrasonic intensity 0.1-1W / cm 2 .

[0022] In one embodiment of the present invention, in step (4), the amount of polydextrose, inulin or oligofructose is 2-5% of the solid matter in the soluble enzymatic hydrolysate.

[0023] In one embodiment of the present invention, in step (5), the pasteurization temperature is 68-75° C. and the time is 2-5 min.

[0024] In one embodiment of the present invention, in step (6), the conditions for low-temperature spray drying are an inlet air temperature of 120-135°C, an outlet air temperature of 65-70°C, and a feed flow rate of 50-100 kg / h.

[0025] In one embodiment of the present invention, in step (7), the powder is granulated using a ring die or flat die granulator, and the granulation diameter is 1-3 mm.

[0026] In one embodiment of the present invention, in step (7), the supercritical carbon dioxide deoiling treatment conditions are: supercritical pressure of 20-29 MPa, temperature of 42-48° C., and carbon dioxide flow rate of 800-1000 L / h.

[0027] In one embodiment of the present invention, in step (7), the pulverization process is ultrafine pulverization, and the pulverization mesh size is 50-200 meshes.

[0028] The second object of the present invention is to provide an egg yolk phospholipid polypeptide powder prepared by the above preparation method.

[0029] The third object of the present invention is to provide an application of the egg yolk phospholipid polypeptide powder in the preparation of a blood lipid regulating composition.

[0030] In one embodiment of the present invention, the blood lipid regulating composition is a functional food, a health food or a medicine.

[0031] [Beneficial Effects]

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention prepares an egg yolk phospholipid polypeptide product with good dissolution and dispersion performance and high oxidation stability by means of the combined use of aqueous enzyme method and supercritical extraction technology.

[0034] The present invention improves the problem of partial insoluble precipitate of egg yolk that cannot be effectively hydrolyzed by neutral protease by means of ultrasound alkaline protease synergistic enzymolysis technology, and realizes the full resource polypeptide transformation of egg yolk protein.

[0035] In the preparation process of the present invention, water-soluble dietary fibers such as polydextrose are added, which not only improves the nutritional value of the egg yolk phospholipid polypeptide, but also can generate a thermal reaction with the ultrasonic enzymatic hydrolyzate to form an egg yolk phospholipid polypeptide product with a stronger antioxidant effect.

[0036] Compared with single egg yolk phospholipid or egg yolk phospholipid protein, the egg yolk phospholipid polypeptide of the present invention has good solubility, dispersibility and oxidation stability. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Without departing from the spirit and essence of the present invention, modifications or replacements made to the method, steps or conditions of the present invention all belong to the scope of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0038] Detection method:

[0039] (1) Powder solubility determination

[0040] Accurately weigh 5 g of sample into a beaker, add 10 mL of deionized water, stir at 25 °C for 30 min to fully dissolve, centrifuge at 4000 r / min for 15 min, pour the supernatant into an evaporating dish with a known constant weight (m1), then evaporate to dryness in a 90 °C water bath, and then dry in a 105 °C oven to constant weight (m2).

[0041] The solubility can be calculated according to the following formula:

[0042]

[0043] (2) Determination of polypeptide content The following method was used for determination.

[0044] Mix the 50 mg / mL sample solution with an equal volume of 10% trichloroacetic acid (TCA), centrifuge at 5000 r / min for 10 min, take the supernatant and dilute to 25 mL with 5% TCA solution. Then mix with biuret reagent at a ratio of 1:4. After incubation at 28°C for 30 min, measure the absorbance at 540 nm, obtain the peptide concentration in the sample solution according to the standard curve, and then calculate the peptide content.

[0045] BSA standard curve: y = 0.0524x + 0.0554, R2 = 0.9997

[0046] (3) ABTS free radical scavenging rate

[0047] Weigh 0.0384 g of ABTS and dilute it to 10 mL as reagent 1, and weigh 0.0134 g of potassium persulfate and dilute it to 10 mL as reagent 2. Mix reagent 1 and reagent 2 in a ratio of 1:1 and shake well. After 12 hours at room temperature and away from light, use it as ABTS working solution. Take an appropriate amount of ABTS working solution and dilute it with 95% ethanol (about 20 to 30 times) until the absorbance at 734 nm is within 0.70±0.02 to use as ABTS solution.

[0048] A1: 0.2 ml sample (1 mg / mL) + 3.8 ml ABTS solution;

[0049] A0: 0.2 ml deionized water + 3.8 ml ABTS solution;

[0050] The mixture was allowed to stand at room temperature for 6 min and the absorbance was measured at 734 nm.

[0051]

[0052] (4) Determination of malondialdehyde content (thiobarbituric acid method)

[0053] The secondary oxidation product malondialdehyde of egg yolk phospholipid polypeptide powder stored at 60°C for 12 days was determined. Thiobarbituric acid solution (TBA solution) is composed of 15% trichloroacetic acid, 0.375% thiobarbituric acid and 1.76% HCl. During the test, 2mL TBA solution was added to a stoppered test tube, 1mL sample (or x amount of sample and 1-xmL water) was added, and deionized water was used as a blank sample. Vortex mix evenly, place in a boiling water bath for 15 minutes, then immediately place in a cold water bath for 10 minutes, centrifuge at 3000rpm at 25°C for 15 minutes, and then place in the dark for 10 minutes, pass through a 0.22μm water film, and take the supernatant to measure the absorbance at a wavelength of 532nm.

[0054] The standard curve (y=0.7262x+0.0037, R 2 =0.9997) for quantification.

[0055] (5) Protein content

[0056] Refer to GB 5009.5-2016.

[0057] (6) Fat content and phospholipid content

[0058] Accurately weigh sample M0 (about 5 g, accurate to 1 mg) and put it into a cylindrical filter paper. Place the filter paper tube in a Soxhlet extraction tube and heat reflux with chloroform-methanol solution in a water bath at about 70°C. Extract for 2-3 hours to allow the fat in the sample to enter the solvent. The residue obtained after rotary evaporation to recover the solvent is the fat (crude fat), and its mass is recorded as M.

[0059]

[0060] The determination of phospholipid content in fat refers to GB / T 5537-2008, and the percentage of phospholipids in the sample is calculated according to the following formula

[0061]

[0062] In the formula: X is the phospholipid content, the unit is g / g.

[0063] (7) Degree of hydrolysis

[0064] The o-phthalaldehyde method (OPA) was used to determine the hydrolysis degree of the sample. The preparation method of OPA was to weigh 200 mg SDS and 7.620 g sodium tetraborate and dissolve them in 150 mL deionized water, then add OPA (160 mg was weighed and dissolved in 4 mL ethanol solution in a dark place) and mix the solution evenly, then add 176 mg and make the volume to 200 mL. The enzymatic solution was diluted 200 times, 400 μL of the sample was added to 3 mL of OPA reagent, reacted at room temperature for 2 minutes, and the absorbance was measured at 340 nm. Serine was used as the standard curve, and the degree of hydrolysis was calculated according to the formula.

[0065]

[0066] In the formula, C-converted serine concentration is calculated by substituting the sample absorbance value into the standard curve, mmol / L;

[0067] N-dilution multiple;

[0068] V-volume of hydrolyzed deoiled egg yolk supernatant solution, L;

[0069] m-mass of protein participating in hydrolysis, g;

[0070] For egg yolk protein, α is 1.00; β is 0.40; and htot is 8.

[0071] (8) Molecular weight distribution

[0072] Sample treatment: Prepare a sample solution with a concentration of 5 mg / mL, filter it through a water-based microporous filter membrane (0.45 μm) and inject it. The liquid phase conditions are as follows: chromatographic column: TSKgel G2000SWxl liquid chromatography column; mobile phase: water / acetonitrile / trifluoroacetic acid (40:60:0.07); flow rate: 1 mL / min; column temperature: 25°C; detection wavelength: 214 nm.

[0073] The standards were cytochrome C (12384 Da), bovine insulin (5733.49 Da), bacitracin (1421.69 Da), reduced glutathione (307.32 Da), and glycine (75.07 Da).

[0074] Standard curve: y = -0.5409x + 7.218, R2 = 0.9853.

[0075] (9) Evaluation of lipid-lowering function

[0076] Experimental design: The mice were randomly divided into groups, with 8 mice in the blank group and 10 mice in each of the other groups. They were blank group, model group, and experimental group. The blank group was male C57BL / 6J mice fed with ordinary feed, and the other groups were male C57BL / 6JGpt DIO mice fed with high-fat feed. After a 1-week adaptation period, the mice were used for the experiment. Days 8 to 38: The blank group and the model group were gavaged with 0.2 ml of normal saline, and the other groups were gavaged with the corresponding amount (once a day). Day 39: The mice were fasted overnight, anesthetized with isoflurane, and blood was collected from the eyeballs and the mice were killed by cervical dislocation. The blood of the mice was collected for determination.

[0077] Experimental Group 1: Sample of Example 1 (1500 mg / kg), Experimental Group 2: Egg yolk phospholipids (ethanol extract of the sample of Example 1 (solid-liquid ratio 1:10), the extract was vacuum dried), Experimental Group 3: Egg yolk polypeptide (ethanol residue of the sample of Example 1 (solid-liquid ratio 1:10), the residue was vacuum dried).

[0078] Index determination methods: Serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined using corresponding commercial kits (Nanjing Jiancheng, China). Serum malondialdehyde content (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were determined using ELISA kits.

[0079] Example 1

[0080] A method for preparing egg yolk phospholipid polypeptide powder comprises the following steps:

[0081] (1) Enzymatic hydrolysis: The egg yolk liquid was diluted with water at a ratio of 1:0.5, preheated to the enzymatic hydrolysis temperature on a plate, and then pumped into an enzymatic hydrolysis tank for composite enzymatic hydrolysis. The enzymatic hydrolysis conditions were: a neutral protease and papain activity ratio of 2:1, a total enzyme activity of 4000 U / g protein, an enzymatic hydrolysis temperature of 45°C, and a hydrolysis time of 8 h.

[0082] (2) Slag separation: The egg yolk liquid after enzymatic hydrolysis in step (1) is separated into soluble enzymatic hydrolysate and insoluble matter by an automatic slag removal precision filter, with a filtration pressure of 0.3 MPa and a filtration accuracy of 1 μm;

[0083] (3) Ultrasonic enzymatic hydrolysis: The insoluble matter obtained in step (2) was diluted with purified water at a ratio of 1:5 and then subjected to ultrasonic enzymatic hydrolysis to obtain an enzymatic product. The ultrasonic enzymatic hydrolysis conditions were as follows: enzymatic hydrolysis pH was 10, the amount of alkaline protease added was 3000 U / g protein, the enzymatic hydrolysis temperature was 55° C., the enzymatic hydrolysis time was 4 h, and the ultrasonic intensity was 1 W / cm 2 ;

[0084] (4) thermal reaction treatment: adding 5% polydextrose by mass to the enzymatic hydrolysate obtained in step (3) and inducing the reaction at 75° C. for 0.5 h;

[0085] (5) Pasteurization: The enzymatic hydrolysates in steps (2) and (4) are combined and pasteurized at 75° C. for 2 min.

[0086] (6) Low-temperature spray drying: The enzymatic hydrolysate after pasteurization in step (5) is subjected to low-temperature spray drying, with an inlet air temperature of 120° C., an outlet air temperature of 65° C., and a feed flow rate of 50 kg / h;

[0087] (7) De-oiling and pulverizing: The dried egg yolk hydrolysate in step (6) is powdered and granulated, and then de-oiled and pulverized using supercritical carbon dioxide. The granulation is performed using a ring die granulator with a granulation diameter of 1 mm. The supercritical carbon dioxide de-oiling treatment conditions are 20 MPa, a temperature of 42° C., and a carbon dioxide flow rate of 800 L / h. The pulverization is performed using low-temperature ultrafine pulverization with a pulverization mesh size of 200 mesh.

[0088] The basic indicators and blood lipid-lowering evaluation of the product obtained in this example are shown in Tables 1 and 2 below, respectively.

[0089] Table 1

[0090] index Example 1 Protein content (g / 100g) 52.8±1.7 Fat content (g / 100g) 36.3±2.2 Phospholipid content (g / 100g) 26.5±2.2 Degree of hydrolysis (%) 22.5±0.5 MW>1000Da 2.5 500<MW≤1000Da 12.2 200<MW≤500Da 38.2 MW≤200Da 47.1

[0091] Table 2

[0092] TC TG LDL-C HDL-C MDA SOD GSH-Px blank 2.43 0.62 0.83 1.80 11.43 84.75 148.50 Model 5.09 0.79 1.74 1.30 32.14 53.94 100.35 Experimental Group 1 4.45 0.71 1.25 1.38 26.55 69.45 118.50 Experimental Group 2 4.55 0.74 1.35 1.33 30.15 56.56 105.45 Experimental Group 3 4.78 0.76 1.52 1.31 26.66 69.48 117.80

[0093] From the results in Table 1, it can be seen that the egg yolk phospholipid polypeptide protein and phospholipid content obtained in Example 1 are relatively high, and the molecular weight of the obtained polypeptides is mostly less than 500Da.

[0094] From the results in Table 2, it can be seen that the egg yolk phospholipid polypeptide sample in experimental group 1 has the best lipid-lowering effect, especially in TC and LDL-C, and its antioxidant index is also better than that of experimental groups 2 and 3, indicating that the coexistence of phospholipids and polypeptides in the egg yolk phospholipid polypeptide product is beneficial to its functional activity. Comparing experimental groups 1, 2 and 3, it can be seen that egg yolk phospholipids have a better lipid-lowering effect, while egg yolk polypeptides have a better antioxidant effect.

[0095] Example 2

[0096] A method for preparing egg yolk phospholipid polypeptide powder comprises the following steps:

[0097] (1) After the egg yolk liquid is diluted with water in a ratio of 1:1, it is preheated to the enzymatic hydrolysis temperature on a plate and then pumped into an enzymatic hydrolysis tank for enzymatic hydrolysis. The enzymatic hydrolysis conditions are: the ratio of neutral protease to papain is 2:1, the total enzyme activity is 8000 U / g protein, the enzymatic hydrolysis temperature is 55°C, and the hydrolysis time is 3 h;

[0098] (2) The egg yolk liquid after enzymatic hydrolysis in step (1) is separated into soluble enzymatic hydrolysate and insoluble matter by an automatic slag removal precision filter, the filtration pressure is 0.2 MPa, and the filtration accuracy is 5 μm;

[0099] (3) The insoluble matter obtained in step (2) was diluted with purified water at a ratio of 1:15 and then subjected to ultrasonic enzymatic hydrolysis to obtain an enzymatic product. The ultrasonic enzymatic hydrolysis conditions were as follows: enzymatic hydrolysis pH was 9, alkaline protease addition amount was 5000 U / g protein, enzymatic hydrolysis temperature was 50° C., enzymatic hydrolysis time was 3 h, and ultrasonic intensity was 0.1 W / cm 2 ;

[0100] (4) thermal reaction treatment: adding 3% inulin by mass to the enzymatic hydrolysate obtained in step (3), and inducing the reaction at 68° C. for 1 h;

[0101] (5) combining the enzymatic hydrolysates from steps (2) and (4) and performing pasteurization at 70° C. for 4 min;

[0102] (6) subjecting the sterilized enzymatic hydrolysate in step (5) to low-temperature spray drying, with an inlet air temperature of 130° C. and an outlet air temperature of 68° C.;

[0103] (7) The dried egg yolk hydrolysate in step (6) is powdered and granulated, and then deoiled with supercritical carbon dioxide and pulverized. The granulation is performed using a ring die granulator with a granulation diameter of 2 mm. The supercritical carbon dioxide deoiling treatment conditions are 25 MPa, a temperature of 45° C., and a carbon dioxide flow rate of 900 L / h. The pulverization treatment is performed using a low-temperature ultrafine pulverization treatment with a pulverization mesh size of 200 mesh.

[0104] Example 3

[0105] A method for preparing egg yolk phospholipid polypeptide powder comprises the following steps:

[0106] (1) After the egg yolk liquid is diluted with water at a ratio of 1:2, it is preheated to the enzymatic hydrolysis temperature on a plate and then pumped into an enzymatic hydrolysis tank for enzymatic hydrolysis. The enzymatic hydrolysis conditions are as follows: the ratio of neutral protease to papain activity is 2:1, the total enzyme activity is 5000 U / g protein, the enzymatic hydrolysis temperature is 50°C, and the hydrolysis time is 6 h;

[0107] (2) The egg yolk liquid after enzymatic hydrolysis in step (1) is separated into soluble enzymatic hydrolysate and insoluble matter by an automatic slag removal precision filter, the filtration pressure is 0.2 MPa, and the filtration accuracy is 10 μm;

[0108] (3) The insoluble matter obtained in step (2) was diluted with purified water at a ratio of 1:10 and then subjected to ultrasonic enzymatic hydrolysis to obtain an enzymatic product. The ultrasonic enzymatic hydrolysis conditions were as follows: enzymatic hydrolysis pH 8, alkaline protease addition amount 6000U / g protein, enzymatic hydrolysis temperature 45°C, enzymatic hydrolysis time 2h, and ultrasonic intensity 0.1W / cm 2 ;

[0109] (4) thermal reaction treatment: adding 2% oligofructose by mass to the hydrolysate obtained in step (3), and inducing the reaction at 55° C. for 2 h;

[0110] (5) combining the enzymatic hydrolysates from steps (2) and (4) and pasteurizing them at 68° C. for 5 min;

[0111] (6) subjecting the sterilized enzymatic hydrolysate in step (5) to low-temperature spray drying, with an inlet air temperature of 135° C. and an outlet air temperature of 70° C.;

[0112] (7) The dried egg yolk hydrolysate in step (6) is powdered and granulated, and then deoiled with supercritical carbon dioxide and pulverized. The granulation is performed using a ring die granulator with a granulation diameter of 3 mm. The supercritical carbon dioxide deoiling treatment conditions are 29 MPa, a temperature of 48° C., and a carbon dioxide flow rate of 1000 L / h. The pulverization treatment is performed using a low-temperature ultrafine pulverization treatment with a pulverization mesh size of 200 mesh.

[0113] Comparative Example 1

[0114] Refer to Example 1, the only difference is that step (1) enzymatic hydrolysis and step (3) ultrasonic enzymatic hydrolysis are not performed.

[0115] Comparative Example 2

[0116] Refer to Example 1, the only difference is that the enzymatic hydrolysis conditions of step (1) and step (3) are swapped.

[0117] Comparative Example 3

[0118] Referring to Example 1, the only difference is that the slag separation step of step (2) is not performed, and after the enzymatic hydrolysis of step (1) is completed, the enzymatic hydrolysis process of step (3) is directly performed.

[0119] Comparative Example 4

[0120] Refer to Example 1, except that the thermal reaction treatment in step (4) is not performed.

[0121] The physical and chemical indicators of the samples obtained in Examples 1-3 and Comparative Examples 1-4 are shown in Table 3 below.

[0122] Table 3

[0123]

[0124]

[0125] As shown in Table 3, the egg yolk phospholipid polypeptides obtained in Examples 1-3 have extremely high solubility, correspondingly high peptide content, high ABTS free radical scavenging rate, and the generation of malondialdehyde can be significantly inhibited during storage.

[0126] By comparing Example 1 and Comparative Example 1, it can be seen that without enzymatic hydrolysis treatment, the solubility and peptide content of the experimental sample are extremely low, and the corresponding ABTS free radical scavenging rate and the inhibitory effect of malondialdehyde generation are also poor, indicating that the two enzymatic hydrolysis treatments in Implementation 1 can greatly improve the solubility, peptide content, free radical scavenging ability and storage stability of the egg yolk phospholipid polypeptide product.

[0127] By comparing Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, the egg yolk dilution is first hydrolyzed with alkaline protease, and then the insoluble matter is hydrolyzed with the composite enzyme, but the effect is not good. The solubility of the egg yolk phospholipid polypeptide sample finally obtained is significantly lower than that of Example 1, which indicates that the composite enzyme cannot effectively hydrolyze the insoluble matter after the hydrolysis by alkaline protease, while the alkaline protease can effectively hydrolyze the insoluble matter after the hydrolysis by the composite enzyme.

[0128] By comparing Example 1 and Comparative Example 3, it can be seen that the ultrasonic alkaline protease hydrolysis process in Comparative Example 3 is not specifically performed on the composite enzyme hydrolysis residue, the hydrolysis efficiency is reduced to a certain extent, and the solubility and peptide content of the finished product are also relatively low.

[0129] By comparing Example 1 and Comparative Example 4, it can be seen that when no thermal reaction treatment is performed in Comparative Example 3, the peptide content of the egg yolk phospholipid polypeptide will be slightly increased, which is related to the fact that the ultrasonic hydrolysate and the water-soluble dietary fiber are not subjected to thermal reaction, and the ABTS free radical scavenging rate will decrease to a certain extent, and the malondialdehyde content will also increase to a certain extent, indicating that the thermal reaction of the ultrasonic hydrolysate and the water-soluble dietary fiber can generate a reaction product with strong antioxidant properties, which is beneficial to improving the storage stability of the egg yolk phospholipid polypeptide.

Claims

1. A method for preparing egg yolk phospholipid polypeptide powder, characterized in that: The following steps are involved: (1) Enzymatic hydrolysis: Mix the egg yolk liquid with water, then add the complex enzyme and perform enzymatic hydrolysis at 40-50°C for 3-8 hours; (2) slag separation: filtering the egg yolk solution after enzymatic hydrolysis in step (1) to separate the soluble enzymatic hydrolyzate and the insoluble matter; (3) Ultrasonic enzymatic hydrolysis: the insoluble matter obtained in step (2) is dispersed in purified water, and then alkaline protease is added, and ultrasonic enzymatic hydrolysis is performed at 45-55° C. for 2-4 hours to obtain a soluble enzymatic hydrolyzate; (4) thermal reaction treatment: adding polydextrose, inulin or oligofructose to the soluble enzymatic hydrolysate obtained in step (3) and inducing the reaction at 55-75° C. for 0.5-2 h; (5) pasteurization: combining the soluble enzymatic hydrolysate from step (2) and the soluble enzymatic hydrolysate treated in step (4) and then performing pasteurization; (6) low temperature spray drying: subjecting the pasteurized enzymatic hydrolysate in step (5) to low temperature spray drying; (7) De-oiling and pulverizing: the egg yolk hydrolysate dried in step (6) is powdered and granulated, then de-oiled with supercritical carbon dioxide, and pulverized to obtain the egg yolk phospholipid polypeptide powder.

2. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of egg yolk liquid to water is 1:0.5-2; The complex enzyme is a mixture of neutral protease and papain; the added amount of the complex enzyme is 4000U / g protein-8000U / g protein.

3. The preparation method according to claim 1, characterized in that: In step (2), the filtration is performed using an automatic slag discharge precision filter with a working pressure of 0.1-0.3 MPa and a filtration accuracy of 1-10 μm.

4. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of insoluble matter to water is 1:5-15; the enzymatic hydrolysis conditions are: enzymatic hydrolysis pH 8-10, alkaline protease addition amount 3000-6000U / g protein, ultrasonic intensity 0.1-1W / cm 2 .

5. The preparation method according to claim 1, characterized in that: In step (4), the amount of polydextrose, inulin or oligofructose is 2-5% of the solid matter in the soluble enzymatic hydrolysate.

6. The preparation method according to claim 1, characterized in that: In step (5), the pasteurization temperature is 68-75° C. and the time is 2-5 min.

7. The preparation method according to claim 1, characterized in that: In step (6), the conditions for low-temperature spray drying are an inlet air temperature of 120-135°C, an outlet air temperature of 65-70°C, and a feed flow rate of 50-100 kg / h.

8. The preparation method according to claim 1, characterized in that: In step (7), the powder is granulated using a ring die or flat die granulator, and the granulation diameter is 1-3 mm; the supercritical carbon dioxide deoiling treatment conditions are: supercritical pressure of 20-29 MPa, temperature of 42-48° C., and carbon dioxide flow rate of 800-1000 L / h; and the pulverization treatment adopts ultrafine pulverization treatment, and the pulverization mesh number is 50-200 mesh.

9. Egg yolk phospholipid polypeptide powder prepared by the preparation method according to any one of claims 1 to 8.

10. An application of the egg yolk phospholipid polypeptide powder according to claim 9, characterized in that: Application in the preparation of blood lipid regulating compositions.

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