Preparation method of egg yolk phosphatide polypeptide powder and application thereof in blood lipid regulation

Abstract

The application discloses a preparation method of egg yolk phospholipid polypeptide powder and application of the egg yolk phospholipid polypeptide powder in blood lipid regulation, and comprises the following steps: (1) enzymolysis treatment; (2) residue separation; (3) ultrasonic enzymolysis; (4) heat reaction treatment; (5) pasteurization; (6) low-temperature spray drying; (7) oil removal and crushing treatment: after the egg yolk enzymolysis material dried in step (6) is granulated into powder, the egg yolk enzymolysis material is subjected to supercritical carbon dioxide oil removal and crushing treatment, so that the egg yolk phospholipid polypeptide powder is obtained. The egg yolk phospholipid polypeptide prepared by the method has good solubility, dispersibility and oxidation stability compared with egg yolk phospholipid.

Description

Technical Field

[0001] This invention relates to the field of functional food ingredients, and in particular to a method for preparing egg yolk phospholipid polypeptide powder and its application in blood lipid regulation. Background Technology

[0002] Egg yolk phospholipids are a mixture of phosphatidylcholine-based phospholipids, typically appearing as a pale yellow waxy solid or paste. They are effective in regulating blood lipids, softening blood vessels, and preventing cardiovascular diseases such as arteriosclerosis, myocardial infarction, and cerebral hemorrhage. However, when used as a functional food ingredient, egg yolk phospholipids face significant limitations in applications such as special dietary foods, health foods, and biomedicine due to their susceptibility to oxidation and poor solubility and dispersibility.

[0003] Egg yolk phospholipid protein is a food ingredient rich in egg yolk phospholipids, produced from egg yolk powder through processes such as granulation, supercritical CO2 extraction, and separation. Its main components are protein (≥40.0g / 100g) and phospholipids (≥24.0g / 100g). CN116268409 A, "An Application of Egg Yolk Lecithin in Assisting in Lowering Serum Triglycerides," discloses an egg yolk phospholipid product (phospholipid mass percentage greater than 24.2%) obtained from egg yolk powder using granulation and supercritical CO2 extraction. This product has a good effect in assisting in lowering 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. This not only affects the sensory experience and stability of the product but also greatly limits its widespread application in solid beverages, special dietary foods, and other food fields requiring good solubility. Summary of the Invention

[0004] [Technical Issues]

[0005] The purpose of this invention is to provide an egg yolk phospholipid polypeptide powder and its application in blood lipid regulation, so as to solve the problem of insufficient solubility of egg yolk phospholipid protein.

[0006] [Technical Solution]

[0007] To achieve the above technical objectives, the present invention adopts the following technical solution:

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

[0009] (1) Enzymatic hydrolysis: Mix egg yolk liquid with water, then add compound enzyme, and hydrolyze at 40-50 ℃ for 3-8 h;

[0010] (2) Slag separation: The egg yolk liquid after enzymatic hydrolysis in step (1) is filtered to separate soluble enzymatic hydrolysate and 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. The mixture is ultrasonically hydrolyzed at 45-55 °C for 2-4 h to obtain soluble enzymatic hydrolysate.

[0012] (4) Thermal reaction treatment: Add polydextrose, inulin or fructooligosaccharide to the soluble enzymatic hydrolysate obtained in step (3), and induce the reaction at 55-75 °C for 0.5-2 h;

[0013] (5) Pasteurization: The soluble enzymatic hydrolysate from step (2) is combined with the soluble enzymatic hydrolysate treated in step (4) and then pasteurized.

[0014] (6) Low-temperature spray drying: The enzymatic hydrolysate after pasteurization in step (5) is subjected to low-temperature spray drying;

[0015] (7) Deoiling and pulverizing treatment: The egg yolk hydrolysate dried in step (6) is granulated into powder and then deoiled by 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 and papain is 2:1, and the amount of complex enzyme added is 4000 U / g protein – 8000 U / g protein.

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

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

[0020] In one embodiment of the present invention, in step (2), the filtration is carried out by 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: pH 8-10, alkaline protease dosage of 3000-6000 U / g protein, and ultrasonic intensity of 0.1-1 W / cm². 2 .

[0022] In one embodiment of the present invention, in step (4), the amount of polydextrose, inulin or fructooligosaccharide used is 2-5% of the solid content 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 ℃, an outlet air temperature of 65-70 ℃, and a feed flow rate of 50-100 kg / h.

[0025] In one embodiment of the present invention, in step (7), the powder granulation is carried out 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 ℃, and carbon dioxide flow rate of 800-1000 L / h.

[0027] In one embodiment of the present invention, in step (7), the pulverization process adopts ultra-fine pulverization, with a pulverization mesh size of 50-200 mesh.

[0028] The second objective of this invention is to provide an egg yolk phospholipid polypeptide powder prepared by the above-described method.

[0029] A third objective of this invention is to provide an application of the above-mentioned egg yolk phospholipid polypeptide powder in the preparation of a lipid-regulating composition.

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

[0031] [Beneficial Effects]

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

[0033] This invention utilizes a combination of aqueous enzymatic method and supercritical extraction technology to prepare egg yolk phospholipid polypeptide products with good solubility and dispersion properties and high oxidative stability.

[0034] This invention improves the problem of insoluble precipitates in egg yolk that cannot be effectively hydrolyzed by neutral proteases by using ultrasonic alkaline protease synergistic enzymatic hydrolysis technology, and realizes the full-resource peptide transformation of egg yolk protein.

[0035] The addition of water-soluble dietary fiber such as polydextrose during the preparation process of this invention not only enhances the nutritional value of egg yolk phospholipid peptides, but also allows them to undergo a thermal reaction with the ultrasonic enzymatic hydrolysate to form egg yolk phospholipid peptide products with stronger antioxidant effects.

[0036] Compared to single egg yolk phospholipids or egg yolk phospholipid proteins, the egg yolk phospholipid polypeptides of this invention have good solubility, dispersibility, and oxidative stability. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement this invention. However, the embodiments are not intended to limit the invention. Modifications or substitutions made to the methods, steps, or conditions of this invention without departing from the spirit and substance of this invention are all within the scope of this 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) Determination of powder solubility

[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 (m1) with known constant weight, then evaporate to dryness in a 90 °C water bath, and then dry in a 105 °C oven to constant weight (m2).

[0041] Solubility can be calculated using the following formula:

[0042] Solubility (g / 100mL water) =

[0043] (2) The polypeptide content was determined by the following method.

[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, and then dilute the supernatant to 25 mL with 5% TCA solution. Next, mix with biuret reagent at a 1:4 ratio. After incubation at 28 ℃ for 30 min, measure the absorbance at 540 nm. Determine the peptide concentration in the sample solution based on 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 bring the volume to 10 mL to obtain Reagent 1. Weigh 0.0134 g of potassium persulfate and bring the volume to 10 mL to obtain Reagent 2. Mix Reagent 1 and Reagent 2 in a 1:1 ratio and shake well. After 12 h at room temperature in the dark, use it as the 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. This solution is then used as the 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] After standing at room temperature for 6 minutes, the absorbance was measured at 734 nm.

[0051] ABTS clearance rate (%) =

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

[0053] Malondialdehyde, a secondary oxidation product of egg yolk phospholipid polypeptide powder stored at 60 °C for 12 days, was determined. The thiobarbituric acid solution (TBA solution) consisted of 15% trichloroacetic acid, 0.375% thiobarbituric acid, and 1.76% HCl. For testing, 2 mL of TBA solution was added to a stoppered test tube, followed by 1 mL of sample (or x parts sample and 1-x mL water), with deionized water as a blank. The mixture was vortexed until homogeneous, heated in a boiling water bath for 15 min, and immediately placed in a cold water bath for 10 min. The mixture was then centrifuged at 3000 rpm at 25 °C for 15 min, and then allowed to stand in the dark for 10 min. The sample was filtered through a 0.22 µm water film, and the absorbance of the supernatant was measured at 532 nm.

[0054] The standard curve obtained using 1,1,3,3-tetraethoxypropane as the standard (y=0.7262x+0.0037, R) 2 Quantification was performed using a value of 0.9997.

[0055] (5) Protein content

[0056] Refer to GB 5009.5-2016.

[0057] (6) Fat content and phospholipid content

[0058] Accurately weigh sample M0 (approximately 5g, accurate to 1 mg) into a cylindrical filter paper tube. Place the filter paper tube into a Soxhlet extraction tube and use a chloroform-methanol solution to heat and reflux in a water bath at approximately 70°C for 2-3 hours. This allows 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 fats shall be in accordance with GB / T 5537-2008. The percentage of phospholipids in the sample shall be calculated according to the following formula.

[0061]

[0062] In the formula: X represents the phospholipid content, in g / g.

[0063] (7) Degree of hydrolysis

[0064] The degree of hydrolysis of the samples was determined using the o-phthalaldehyde (OPA) method. The OPA preparation method was as follows: 200 mg of SDS and 7.620 g of sodium tetraborate were dissolved in 150 mL of deionized water. Then, 160 mg of OPA (dissolved in 4 mL of ethanol solution in the dark) was added and mixed thoroughly. Finally, 176 mg of OPA was added, and the volume was adjusted to 200 mL. The enzymatic hydrolysate was diluted 200-fold, and 400 μL of sample was added to 3 mL of OPA reagent. The reaction was carried out at room temperature for 2 min, and the absorbance was measured at 340 nm. A standard curve was prepared using serine, and the degree of hydrolysis was calculated using the formula.

[0065]

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

[0067] N - Dilution factor;

[0068] V - Volume of hydrolyzed and degreased egg yolk supernatant, L;

[0069] m - the mass of the protein involved in hydrolysis, in grams;

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

[0071] (8) Molecular weight distribution

[0072] Sample preparation: Prepare a sample solution with a concentration of 5 mg / mL, filter it through an aqueous microporous membrane (0.45 μm), and then inject the sample. The liquid chromatography conditions are as follows: Column: TSKgel G2000SWxl liquid chromatography column; Mobile phase: water / acetonitrile / trifluoroacetic acid (40:60:0.07); Flow rate: 1 mL / min; Column temperature: 25 ℃; 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: Mice were randomly divided into three groups: a control group (n=8) and other groups (n=10 each). These groups were the control group, model group, and experimental group. The control group consisted of male C57BL / 6J mice fed a standard diet, while the other groups consisted of male C57BL / 6JGpt DIO mice fed a high-fat diet. After a one-week acclimatization period, the mice were used in the experiment. From day 8 to 38: The control and model groups were administered 0.2 ml of physiological saline by gavage, while the other groups received the corresponding amount via gavage (once a day). On day 39: Mice were fasted overnight, anesthetized with isoflurane, and euthanized by cervical dislocation after blood collection from the eyeballs. Blood was collected for analysis.

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

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

[0079] Example 1

[0080] A method for preparing egg yolk phospholipid polypeptide powder includes 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 compound enzymatic hydrolysis. The enzymatic hydrolysis conditions were: neutral protease and papain activity ratio of 2:1, total enzyme activity of 4000 U / g protein, enzymatic hydrolysis temperature of 45℃, and hydrolysis time of 8h.

[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 separation precision filter. The filtration pressure is 0.3 MPa and the filtration accuracy is 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 the hydrolysate. The ultrasonic enzymatic hydrolysis conditions were as follows: hydrolysis pH was 10, alkaline protease was added at a rate of 3000 U / g protein, hydrolysis temperature was 55℃, hydrolysis time was 4h, and ultrasonic intensity was 1 W / cm. 2 ;

[0084] (4) Thermal reaction treatment: Add 5% polydextrose to the enzymatic hydrolysate obtained in step (3) by mass percentage, and induce the reaction at 75 ℃ for 0.5 h;

[0085] (5) Pasteurization: The enzymatic hydrolysates from steps (2) and (4) are combined and then 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 ℃, an outlet air temperature of 65 ℃, and a feed flow rate of 50 kg / h.

[0087] (7) Deoiling and pulverizing treatment: The egg yolk hydrolysate dried in step (6) is granulated into powder and then deoiled and pulverized using supercritical carbon dioxide. The granulation is carried out using a ring die granulator with a granulation diameter of 1 mm. The supercritical carbon dioxide deoiling treatment conditions are 20 MPa, 42 ℃, and carbon dioxide flow rate of 800 L / h. The pulverizing treatment is carried out using low-temperature ultrafine pulverization with a pulverization mesh of 200 mesh.

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

[0089] Table 1

[0090]

[0091] Table 2

[0092]

[0093] As can be seen from the results in Table 1, the egg yolk phospholipid polypeptides obtained in Example 1 have high protein and phospholipid content, and most of the polypeptides have a molecular weight of less than 500 Da.

[0094] As shown in Table 2, the egg yolk phospholipid peptide sample in experimental group 1 exhibited the best lipid-lowering effect, especially in terms of TC and LDL-C. Its antioxidant index was also superior to that of experimental groups 2 and 3, indicating that the simultaneous presence of phospholipids and peptides in the egg yolk phospholipid peptide product is beneficial to its functional activity. Comparing experimental groups 1, 2, and 3, it is clear that egg yolk phospholipids have a better lipid-lowering effect, while egg yolk peptides have a better antioxidant effect.

[0095] Example 2

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

[0097] (1) After diluting the egg yolk liquid with water at a ratio of 1:1, it was preheated to the enzymatic hydrolysis temperature by a plate and then pumped into an enzymatic hydrolysis tank for enzymatic hydrolysis. The enzymatic hydrolysis conditions were: neutral protease and papain activity ratio of 2:1, total enzyme activity of 8000 U / g protein, enzymatic hydrolysis temperature of 55 ℃, and hydrolysis time of 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 discharge 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 the hydrolysate. The ultrasonic enzymatic hydrolysis conditions were as follows: hydrolysis pH of 9, alkaline protease addition of 5000 U / g protein, hydrolysis temperature of 50 ℃, hydrolysis time of 3 h, and ultrasonic intensity of 0.1 W / cm 2 ;

[0100] (4) Thermal reaction treatment: Add 3% inulin to the enzymatic hydrolysate obtained in step (3) by mass percentage, and induce the reaction at 68 ℃ for 1 h;

[0101] (5) Combine the enzymatic hydrolysates from steps (2) and (4) and pasteurize them at 70 °C for 4 min.

[0102] (6) The enzymatic hydrolysate sterilized in step (5) is subjected to low-temperature spray drying with an inlet air temperature of 130 ℃ and an outlet air temperature of 68 ℃.

[0103] (7) After drying the egg yolk hydrolysate in step (6), the powder was granulated and then deoiled by supercritical carbon dioxide and pulverized. The granulation was carried out by a ring die granulator with a granulation diameter of 2 mm. The supercritical carbon dioxide deoiling conditions were 25 MPa, 45 °C, and 900 L / h. The pulverization was carried out by low-temperature ultrafine pulverization with a pulverization mesh of 200 mesh.

[0104] Example 3

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

[0106] (1) After diluting the egg yolk liquid with water at a ratio of 1:2, it was preheated to the enzymatic hydrolysis temperature by a plate and then pumped into an enzymatic hydrolysis tank for enzymatic hydrolysis. The enzymatic hydrolysis conditions were: neutral protease and papain activity ratio of 2:1, total enzyme activity of 5000 U / g protein, enzymatic hydrolysis temperature of 50 ℃, and hydrolysis time of 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 discharge 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 the hydrolysate. The ultrasonic enzymatic hydrolysis conditions were as follows: hydrolysis pH 8, alkaline protease addition of 6000 U / g protein, hydrolysis temperature of 45 ℃, hydrolysis time of 2 h, and ultrasonic intensity of 0.1 W / cm 2 ;

[0109] (4) Thermal reaction treatment: Add 2% oligofructose to the enzymatic hydrolysate obtained in step (3) by mass percentage, and induce the reaction at 55 ℃ for 2 h;

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

[0111] (6) The enzymatic hydrolysate sterilized in step (5) is spray-dried at low temperature with an inlet air temperature of 135°C and an outlet air temperature of 70°C.

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

[0113] Comparative Example 1

[0114] Referring 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] Referring to Example 1, the only difference is that the enzymatic hydrolysis conditions in steps (1) and (3) are interchanged.

[0117] Comparative Example 3

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

[0119] Comparative Example 4

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

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

[0122] Table 3

[0123]

[0124] As shown in Table 3, the egg yolk phospholipid peptides obtained in Examples 1-3 have extremely high solubility, correspondingly high peptide content, high ABTS free radical scavenging rate, and significantly inhibited malondialdehyde generation during storage.

[0125] Comparing Example 1 and Comparative Example 1, it can be seen that without enzymatic hydrolysis, the solubility and peptide content of the experimental samples are extremely low, and the corresponding ABTS free radical scavenging rate and malondialdehyde generation inhibition effect are also poor. This indicates that the two enzymatic hydrolysis treatments in Example 1 can greatly improve the solubility, peptide content, free radical scavenging ability and storage stability of egg yolk phospholipid peptide products.

[0126] Comparing Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, the effect of first hydrolyzing the egg yolk dilution with alkaline protease and then hydrolyzing the insoluble matter with the complex enzyme was not good. The solubility of the egg yolk phospholipid polypeptide sample obtained was significantly lower than that in Example 1. This indicates that the complex enzyme cannot effectively hydrolyze the insoluble matter after alkaline protease hydrolysis, while alkaline protease can effectively hydrolyze the insoluble matter after complex enzyme hydrolysis.

[0127] Comparing Example 1 and Comparative Example 3, it can be seen that the ultrasonic alkaline protease hydrolysis process in Comparative Example 3 was not specifically targeted at the hydrolysis residue of the complex enzyme, resulting in a certain reduction in hydrolysis efficiency and relatively low solubility and peptide content of the finished product.

[0128] Comparing Example 1 and Comparative Example 4, it can be seen that in Comparative Example 3, when no thermal reaction treatment is performed, the peptide content of egg yolk phospholipid peptides will be slightly increased. This is related to the fact that the ultrasonic enzymatic hydrolysate and water-soluble dietary fiber did not undergo thermal reaction. The ABTS free radical scavenging rate will decrease to a certain extent, and the malondialdehyde content will also increase to a certain extent. This indicates that the thermal reaction between the ultrasonic enzymatic hydrolysate and water-soluble dietary fiber can generate reaction products with strong antioxidant properties, which is beneficial to improving the storage stability of egg yolk phospholipid peptides.

Claims

1. A method for preparing egg yolk phospholipid polypeptide powder, characterized in that, Includes the following steps: (1) Enzymatic hydrolysis: Mix egg yolk liquid with water, then add compound enzyme, and hydrolyze at 40-50 ℃ for 3-8 h; The mass ratio of egg yolk liquid to water is 1:0.5-2; the compound enzyme is a mixture of neutral protease and papain; the amount of compound enzyme added is 4000 U / g protein – 8000 U / g protein; (2) Slag separation: The egg yolk liquid after enzymatic hydrolysis in step (1) is filtered to separate soluble enzymatic hydrolysate and insoluble matter; (3) Ultrasonic enzymatic hydrolysis: The insoluble matter obtained in step (2) is dispersed in purified water, and then alkaline protease is added. The mixture is ultrasonically hydrolyzed at 45-55℃ for 2-4 h to obtain soluble enzymatic hydrolysate. The mass ratio of insoluble matter to water is 1:5-15; the enzymatic hydrolysis conditions are: pH 8-10, alkaline protease dosage of 3000-6000 U / g protein, and ultrasonic intensity of 0.1-1 W / cm². 2 ; (4) Thermal reaction treatment: Add polydextrose, inulin or fructooligosaccharide to the soluble enzymatic hydrolysate obtained in step (3), and induce the reaction at 55-75 °C for 0.5-2 h; The amount of polydextrose, inulin, or fructooligosaccharide used is 2-5% of the solid content in the soluble enzymatic hydrolysate; (5) Pasteurization: The soluble enzymatic hydrolysate from step (2) is combined with the soluble enzymatic hydrolysate treated in step (4) and then pasteurized. (6) Low-temperature spray drying: The enzymatic hydrolysate after pasteurization in step (5) is subjected to low-temperature spray drying; (7) Deoiling and pulverizing treatment: The egg yolk hydrolysate dried in step (6) is granulated into powder and then deoiled by supercritical carbon dioxide and pulverized to obtain the egg yolk phospholipid polypeptide powder. Powder granulation uses a ring die or flat die granulator with a granulation diameter of 1-3 mm; the supercritical carbon dioxide deoiling treatment conditions are: supercritical pressure of 20-29 MPa, temperature of 42-48℃, and carbon dioxide flow rate of 800-1000 L / h; the pulverization treatment uses ultrafine pulverization with a pulverization mesh of 50-200 mesh.

2. The preparation method according to claim 1, characterized in that, In step (2), filtration is carried out 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.

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

4. 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℃, an outlet air temperature of 65-70℃, and a feed flow rate of 50-100 kg / h.

5. An egg yolk phospholipid polypeptide powder prepared by the preparation method according to any one of claims 1-4.

6. An application of the egg yolk phospholipid polypeptide powder according to claim 5, characterized in that, Application in the preparation of lipid-regulating compositions.

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