Application of wheat germ protein hydrolysate in preparation of product for inhibiting grease absorption

Abstract

The invention belongs to the technical field of functional food and medicine, and particularly relates to application of wheat germ protein hydrolysate in preparation of products for inhibiting grease absorption, the wheat germ protein hydrolysate comprises peptide fragments with molecular weight smaller than 1000 Da, GRAVY value larger than 0 and isoelectric point smaller than 6, the inhibition rate of the wheat germ protein hydrolysate to grease cholesterol micelle solubility can reach 55% or above, and the inhibition rate of the wheat germ protein hydrolysate to grease cholesterol micelle solubility can reach 55% or above. The wheat germ protein prepared by using the method is resistant to gastrointestinal digestion, can obviously inhibit Caco-2 cells from absorbing and transporting cholesterol, and can be used for preparing products for inhibiting oil absorption, so that the application field of the wheat germ protein is expanded, and effective increment of wheat processing byproducts and effective utilization of resources are realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of functional food or medicine, and particularly relates to application of wheat germ protein enzymolysis product in preparation of oil absorption inhibiting product. BACKGROUND

[0002] With the improvement of living standards, people's diet and living habits have changed. Long-term intake of high-sugar and high-fat food and lack of exercise lead to an increasing number of people with high blood lipid levels and cholesterol homeostasis disorders, thereby increasing the risk of atherosclerosis, heart disease, cardiovascular and cerebrovascular diseases, obesity, diabetes, fatty liver, osteoporosis and cancer. Maintaining cholesterol homeostasis in the body can effectively prevent the occurrence of cardiovascular and cerebrovascular diseases. Current common cholesterol-lowering drugs include statins (competitive HMGCR inhibitors), ezetimibe (cholesterol absorption inhibitors), bile acid sequestrants, fibrates (phenoxy acid lipid-regulating drugs) and niacin. Although the use of these drugs can significantly reduce plasma cholesterol levels, long-term use may cause side effects such as headache, muscle weakness, liver dysfunction and other adverse effects, which is not conducive to human health. Therefore, it is necessary to find some new natural blood lipid-lowering active ingredients with obvious blood lipid-lowering effect, safety and reliability, and economy.

[0003] Wheat germ has various physiological active ingredients, and the proportion of amino acids is reasonable, so it is a very valuable natural protein resource. However, the presence of wheat germ in the flour industry can seriously affect the quality and storage period of flour, and producers mostly strive to remove it to the greatest extent, which causes great waste of this high-quality resource. Wheat germ peptides, as a high-quality new plant resource and nutritional source, are welcomed by people and are widely used in various researches. At present, the research on wheat germ peptides is mostly focused on their antioxidant and blood pressure-lowering effects, and there is little research on their blood lipid-lowering effect, and the technology is lacking. Therefore, it is crucial to find a suitable processing method and application to improve the added value of wheat germ peptides. SUMMARY

[0004] In view of the problems in the prior art, the application provides application of wheat germ protein enzymolysis product in preparation of oil absorption inhibiting product by exploring the new function of the wheat germ protein enzymolysis product. The wheat germ protein enzymolysis product contains a peptide segment with a molecular weight less than 1000 Da, a GRAVY value greater than 0 and an isoelectric point less than 6. The test verification shows that the inhibition rate of the oil cholesterol micelle solubility is more than 55%, the wheat germ protein enzymolysis product is resistant to gastrointestinal digestion, can significantly inhibit the absorption and transport of cholesterol by Caco-2 cells, and can be used for preparing oil absorption inhibiting product, thereby expanding the application field of wheat germ protein, realizing effective value-added of wheat processing by-products and effective utilization of resources.

[0005] The inhibiting oil absorption product includes food or medicine, the food includes ordinary food, health food, special medical purpose formula food, the medicine includes hypolipidemic drug, is used for realizing or improving the efficacy of controlling blood lipid.

[0006] Further, the inventors provide a preparation method of the above wheat germ protein hydrolysate, comprising the following steps: (1) Extracting wheat germ protein: crushing defatted wheat germ, adding deionized water, adjusting pH and temperature to extract protein, taking supernatant and adding amylase to remove starch, adjusting pH to 4.0 to precipitate protein, washing the precipitate, adding deionized water to the precipitate, adjusting pH to neutral, stirring and dissolving to obtain a wheat germ protein solution.

[0007] (2) Enzymatic hydrolysis: diluting the wheat germ protein solution, adjusting pH and temperature, then adding protease to the protein solution, hydrolyzing, inactivating the enzyme after hydrolysis, and separating to obtain supernatant, which is the wheat germ protein hydrolysate.

[0008] (3) Enriching functional peptides: treating the wheat germ protein hydrolysate with ultrafiltration membrane and macroporous resin to obtain the wheat germ protein hydrolysate.

[0009] Preferably, in step (1), the ratio of defatted wheat germ powder to deionized water is 1:10-1:30 (g / mL); the pH is 6-12, and the temperature is 40-65°C; the supernatant is obtained by filtration or centrifugation; the amylase is one or both of high-temperature α-amylase and β-amylase, the hydrolysis pH is 5.0-7.0, the hydrolysis temperature is 40-70°C, the hydrolysis time is 0.5-3 h, and the enzyme addition amount is 2-50 U per milliliter of supernatant; the washing frequency of the precipitate is 2 times.

[0010] Preferably, in step (2), the concentration of the diluted wheat germ protein is 5-15% (5-15 g of wheat germ protein in 100 mL of solution); the pH is 7.0-10.0, and the temperature is 45-65°C; the protease is one or more of papain, alkaline protease, neutral protease, complex protease, or flavor protease, and the enzyme addition amount is 2% based on the weight of protein; the hydrolysis time is 200-400 min; and the enzyme inactivation method is boiling in 100°C boiling water for 5-20 min.

[0011] Preferably, in step (3), the ultrafiltration membrane has a molecular weight cut-off of 1000-5000 Da; the macroporous resin is a non-polar macroporous resin, the desorption solution is 25-85% (v / v) ethanol solution, the enzyme hydrolysate ethanol solution obtained by desorption is vacuumed to remove ethanol, and then spray dried to obtain the target wheat germ protein hydrolysate.

[0012] In the technical solution, the pH adjusting agent is a 2 mol / L NaOH solution or a 2 mol / L HCl solution.

[0013] Compared with the prior art, the present application has the following advantages: (1) The wheat germ protein enzymolysis product provided by the present application has a cholesterol micelle solubility inhibition rate of 55% or higher, is resistant to gastrointestinal digestion, can significantly inhibit the absorption and transport of cholesterol by Caco-2 cells, is natural and safe in source, has low preparation cost, and can be applied to the preparation of products for inhibiting the absorption of oil and fat.

[0014] (2) Each process flow adopted in the preparation of the wheat germ protein enzymolysis product is a large-flux process, which is convenient for industrialized production and effective value-added processing of wheat processing by-products and effective utilization of resources. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Digestion stability of the wheat germ protein enzymolysis product obtained in Example 2; Figure 2 Effect of the wheat germ protein enzymolysis product obtained in Example 2 at different concentrations on the transport of cholesterol by Caco-2 cells. DETAILED DESCRIPTION

[0016] In order to better understand the present application, the following embodiments and drawings are further described to illustrate the content of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0017] Example 1: A preparation method of a wheat germ protein enzymolysis product with an oil and fat absorption inhibiting function, specifically comprising the following steps: (1) Extracting wheat germ protein: after the defatted wheat germ is crushed, the crushed defatted wheat germ is added into deionized water at a ratio of 1:10 (g / mL), a 2 mol / L NaOH solution is used to adjust the pH to 9.0, the temperature is adjusted to 40℃, and the protein is extracted by stirring for 2 h. The supernatant is obtained by centrifugation, 2 U / mL α-amylase is added into the supernatant, the temperature is adjusted to 40℃, a 2 mol / L HCl solution is used to adjust the pH to 5.0, and the starch is removed by enzymolysis for 1 h. The pH of the supernatant is adjusted to 4.0 by using a 2 mol / L HCl solution, and the protein precipitate is obtained by centrifugation. The precipitate is washed with water for 2 times, deionized water is added into the precipitate, a 2 mol / L NaOH solution is used to adjust the pH to neutral, and the precipitate is dissolved by stirring to obtain a wheat germ protein solution; (2) Enzymatic hydrolysis: dilute the wheat germ protein solution to 5%, adjust the pH to 7.0 with 2 mol / L NaOH solution, adjust the temperature to 45℃, then add 2 wt% of alkaline protease to the protein solution, hydrolyze for 200 min, after the enzymatic hydrolysis, place it in boiling water at 100℃ for 10 min to inactivate the enzyme, and after cooling, centrifuge to obtain the supernatant, which is the wheat germ protein hydrolysate; (3) Enrichment of functional peptides: the wheat germ protein hydrolysate is subjected to ultrafiltration using an ultrafiltration membrane with a molecular weight cut-off of 2000 Da, the cut-off liquid is adsorbed with DA201-C macroporous resin, and gradient elution is performed using ethanol solutions with a volume fraction of 25% and 50%, and the 50% ethanol eluate is spray dried after vacuum removal of ethanol to obtain the wheat germ protein hydrolysate with the highest activity.

[0018] Example 2 A preparation method of a wheat germ protein hydrolysate with the function of inhibiting fat absorption, specifically comprising the following steps: (1) Extracting wheat germ protein: crush the defatted wheat germ, add deionized water at a ratio of 1:20 (g / mL), adjust the pH to 9.0 with 2 mol / L NaOH solution, adjust the temperature to 50℃, and stir for 2 h to extract the protein, centrifuge to obtain the supernatant, add 20 U / mL of α-amylase to the supernatant, adjust the temperature to 50℃, adjust the pH to 6.0 with 2 mol / L HCl solution, and hydrolyze for 2 h to remove starch. Adjust the pH of the supernatant to 4.0 with 2 mol / L HCl solution, centrifuge to obtain the protein precipitate, wash the precipitate twice with water, add deionized water to the precipitate, adjust the pH to neutral with 2 mol / L NaOH solution, stir to dissolve, and obtain a wheat germ protein solution.

[0019] (2) Enzymatic hydrolysis: dilute the wheat germ protein solution to 10%, adjust the pH to 8.0 with 2 mol / L NaOH solution, adjust the temperature to 50℃, then add 2 wt% of alkaline protease to the protein solution, hydrolyze for 300 min, after the enzymatic hydrolysis, place it in boiling water at 100℃ for 20 min to inactivate the enzyme, and after cooling, centrifuge to obtain the supernatant, which is the wheat germ protein hydrolysate.

[0020] (3) Enrichment of functional peptides: the wheat germ protein hydrolysate is subjected to ultrafiltration using an ultrafiltration membrane with a molecular weight cut-off of 2000 Da, the cut-off liquid is adsorbed with DA201-C macroporous resin, and gradient elution is performed using ethanol solutions with a volume fraction of 50% and 75%, and the 75% ethanol eluate is spray dried after vacuum removal of ethanol to obtain the wheat germ protein hydrolysate with the highest activity.

[0021] Example 3 A preparation method of a wheat germ protein hydrolysate with the function of inhibiting fat absorption, specifically comprising the following steps: (1) Extraction of wheat germ protein: defatted wheat germ was crushed and added to deionized water at a ratio of 1:30 (g / mL), and the pH was adjusted to 9.0 with 2 mol / L NaOH solution. The temperature was adjusted to 65°C, and the protein was extracted by stirring for 2 h. The supernatant was obtained by centrifugation. 40 U / mL of α-amylase and 10 U / mL of β-amylase were added to the supernatant, and the temperature was adjusted to 70°C. The pH was adjusted to 7.0 with 2 mol / L HCl solution, and the starch was removed by enzymatic hydrolysis for 3 h. The pH of the supernatant was adjusted to 4.0 with 2 mol / L HCl solution, and the protein precipitate was obtained by centrifugation. The precipitate was washed with water twice, and deionized water was added to the precipitate. The pH was adjusted to neutral with 2 mol / L NaOH solution, and the precipitate was dissolved by stirring to obtain a wheat germ protein solution.

[0022] (2) Enzymatic hydrolysis: the wheat germ protein solution was diluted to 15%, and the pH was adjusted to 10.0 with 2 mol / L NaOH solution. The temperature was adjusted to 60°C, and then 2 wt% of alkaline protease was added to the protein solution. The enzymatic hydrolysis was carried out for 400 min, and then the enzyme was inactivated by boiling in 100°C water for 20 min. After cooling, the supernatant was obtained by centrifugation, and the supernatant was the wheat germ protein hydrolysate.

[0023] (3) Enrichment of functional peptides: the wheat germ protein hydrolysate was subjected to ultrafiltration using an ultrafiltration membrane with a molecular weight cutoff of 2000 Da. The retentate was adsorbed on a DA201-C macroporous resin, and gradient elution was performed using ethanol solutions with a volume fraction of 25% and 75%. The 75% ethanol eluate was spray dried after vacuum removal of ethanol to obtain the wheat germ protein hydrolysate with the highest activity.

[0024] Experimental Example 1. Determination of inhibition rate of cholesterol micelle solubility 1 mmol / L of oleic acid, 0.4 mmol / L of cholesterol, and 2.4 mmol / L of phosphatidylcholine were dissolved in methanol and dried. Then, 10 mmol / L of sodium taurocholate, 132 mmol / L of NaCl, and 15 mmol / L of sodium phosphate buffer were added to prepare a micelle solution.

[0025] The micelle solution was ultrasonicated at 210 W for 20 min and incubated at 37°C for 24 h. After incubation, the solid wheat germ protein hydrolysate prepared in the above example was added to the micelle solution to prepare a 5 mg / mL solution. After ultrasonication at 210 W, the solution was incubated at 37°C for 24 h, centrifuged at 1000 g for 10 min, and the supernatant was filtered through a 0.22 μm membrane. The cholesterol concentration was determined by OPA colorimetry, and the inhibition rate was calculated according to the following formula. The results are shown in Table 1. C = (S0-S1) / S0 x 100% , C: inhibition rate of cholesterol micelle solubility, % S0: micellar cholesterol concentration, mmol / L; S1: micellar cholesterol concentration of enzymatic hydrolysate, mmol / L.

[0026] Table 1 Cholesterol micellar solubility inhibition rate of wheat germ protein enzymatic hydrolysate of each example .

[0027] 2. Determination of molecular weight distribution The molecular weight distribution of the wheat germ protein enzymatic hydrolysate prepared in the above examples was determined by high performance liquid chromatography. The wheat germ protein enzymatic hydrolysate was added to deionized water to prepare a solution with a concentration of 1 mg / mL, shaken to dissolve thoroughly, filtered through a 0.22 µm microporous filter, and placed in a sample bottle for standby; the mobile phase was prepared according to the ratio of acetonitrile: ultrapure water: trifluoroacetic acid = 45:55:0.1, and then filtered through a 0.22 µm organic phase filter. After ultrasonic degassing, it was ready for use; column: TSK gel 2000SWXL type (7.8 mm x 300 mm); detector: ultraviolet detector; wavelength: 220 nm; column temperature: 30°C; flow rate: 0.5 mL / min. The molecular weight distribution results were obtained by comparing the standard samples, as shown in Table 2.

[0028] Table 2 Molecular weight distribution (%) of wheat germ protein enzymatic hydrolysate of each example .

[0029] 3. Structural identification of wheat germ protein The peptide segment structure of the wheat germ protein enzymatic hydrolysate prepared in Example 2 was determined using a high performance liquid chromatograph (Easy-NanoLC1200, Thermo Fisher Science, Waltham) equipped with a C18 column (50 μm x 150 mm, AcClaine PepMapTM RSLC, Thermo Scientific Technology Inc) and a high-resolution mass spectrometer (Q-Exactive HF, Thermo Fisher). The desalted sample was dissolved in 0.1% (v / v) formic acid solution with a concentration of 1 mg / mL. The injection volume was 1 µL, the flow rate was 300 nL / min, and the column temperature was 30°C. The mobile phase A was 0.1% formic acid aqueous solution, and the mobile phase B was 0.1% (v / v) formic acid acetonitrile aqueous solution (acetonitrile was 80%). The separation conditions were as follows: 8~28% (0~98 min), 28~37% (98~113 min), 37~100% (113~117 min), 100% (117~120 min).

[0030] The mass spectrometry conditions are as follows: (1) detection mode: positive ion; (2) full MS scan range (m / z) = 400-1800; (3) first-order resolution = 60000; (4) second-order resolution = 15000; (5) collision energy = 28 eV.

[0031] The identified peptide fragments were analyzed for molecular weight, hydrophobicity and isoelectric point using Expasy and PepCalc. The results are shown in Table 3.

[0032] Table 3 Peptide fragment information of Example 2 It can be seen that the wheat germ protein hydrolysate obtained in Example 2 contains peptide fragments with a molecular weight less than 1000 Da, a GRAVY value greater than 0, and an isoelectric point less than 6.

[0033] 4. Digestion stability of wheat germ protein hydrolysate The preparation of simulated gastrointestinal digestion solutions is shown in Table 4. SSF, SGF and SIF are simulated oral cavity digestion solution, simulated gastric digestion solution and simulated intestinal digestion solution, respectively, and are added according to the amounts shown in the table, then diluted to 400 mL with deionized water and further diluted 1.5 times.

[0034] Table 4 Preparation of simulated gastrointestinal digestion solutions in vitro In the simulated oral cavity digestion test, 7.5 mL of SSF and 7.5 mL of the wheat germ protein hydrolysate aqueous solution (10 mg / mL) prepared in Example 2 were mixed and placed in a 37°C environment for 2 min of uniform reaction; After oral cavity digestion, 15 mL of SGF and 2.4 mL of pepsin solution (2000 U / mL) were added, the pH was adjusted to 3 with 1 mol / L HCl, and the mixture was uniformly reacted at 37°C for 120 min. After the reaction was completed, the pH was adjusted to neutral and the enzyme was inactivated at 100°C to terminate the reaction. After gastric digestion, 30 mL of SIF, 10.9 mL of trypsin (100 U / mL) and 6.82 mL of cholate were added, the pH of the mixture was adjusted to 7 with 1 mol / L NaOH, and the mixture was uniformly reacted at 37°C for 120 min. After the reaction was completed, the enzyme was inactivated at 100°C to terminate the reaction.

[0035] The digestion solutions taken at 2, 62, 122, 182 and 242 min of the above simulated digestion were dialyzed using a dialysis bag with a molecular weight cutoff of 100 Da, then freeze-dried, and the cholesterol micelle solubility inhibition rate was determined. The digestion stability of the wheat germ protein hydrolysate was represented by the relative inhibition rate, and the calculation formula of the relative inhibition rate is as follows: Results are shown in Figure 2. Figure 1 As can be seen from the figure, the relative inhibition rate of the enzymatic hydrolysate prepared in Example 2 increased first, then decreased, and then increased again as the digestion proceeded. The lowest relative inhibition rate during the digestion was 98%, and the relative inhibition rate after the simulated digestion was 110%, indicating that the digestion process did not reduce the cholesterol micelle solubility inhibition activity of the wheat germ protein enzymatic hydrolysate, but rather enhanced the activity.

[0036] 5. Effect of wheat germ protein enzymatic hydrolysate on Caco-2 cell transport of cholesterol The micellar solution containing 100 μmol / L 22-NBD cholesterol, 1 mmol / L oleic acid, 0.5 mmol / L monoglyceride, 6.6 mmol / L sodium taurocholate, and 0.1 mmol / L lecithin was dissolved in 1% DMSO (dimethyl sulfoxide) HBSS solution, adjusted to pH 7.2, filtered with a 0.22 μm microporous filter to remove bacteria, and stored at 37°C for standby.

[0037] The solid wheat germ protein enzymatic hydrolysate prepared in Example 2 was added to the above-mentioned cholesterol micellar solution to prepare micellar solutions of 1.25, 2.5, and 5 mg / mL, respectively. The solid obtained by freeze-drying after the simulated digestion for 242 min in Example 4 was added to the above-mentioned cholesterol micellar solution to prepare a micellar solution of 2 mg / mL. The micellar solutions were filtered with a 0.22 μm microporous filter to remove bacteria, and stored at 37°C for standby.

[0038] The Caco-2 cells cultured for 21 days and meeting the conditions and having a perfect morphology were selected, the old culture medium on the BL side and the AP side was removed, the cells were washed 3 times with HBSS buffer, and the HBSS buffer on the AP side and the BL side was aspirated. The Transwell chamber was transferred to a new 12-well plate, and the residual liquid was aspirated as much as possible. Then, 1.5 mL of HBSS buffer was added to the BL side, and 0.5 mL of the cholesterol micellar solution, the micellar solution containing 1.25, 2.5, or 5 mg / mL of the wheat germ protein enzymatic hydrolysate, and the micellar solution containing 2 mg / mL of the wheat germ protein enzymatic hydrolysate after the simulated digestion were added to the AP side, each group had 4 parallels, and the mixture was incubated in a 37°C, 5% CO2 incubator for 2 h. 200 μL of the sample was taken from the BL side at 30, 60, 90, and 120 min, and added to a 96-well plate, and then the same volume of HBSS buffer was added to the BL side. The fluorescence intensity was measured at 472 / 540 nm. The relative transport rate of cholesterol was calculated according to the following formula: Results Figure 2As shown, the relative transport rate gradually increased with the extension of transport time, indicating that cholesterol was gradually transported into the Caco-2 monolayer cell membrane. After 120 min of transport, the wheat germ protein hydrolysate prepared in Example 2 significantly inhibited the transport of cholesterol by Caco-2 cells, and the transport amount was reduced by 11% to 22%. With the increase of the concentration of the wheat germ protein hydrolysate, the inhibition rate gradually increased, and when the concentration was 5 mg / mL, the inhibition rate was the largest, being 21.65%. After simulated digestion, the transport inhibition rate of the wheat germ protein hydrolysate (2 mg / mL) was 16.77%, which was similar to the inhibition effect when the concentration was 2.5 mg / mL. It was indicated that the wheat germ protein hydrolysate in the present application could effectively inhibit the transport of cholesterol by Caco-2 cells, whether or not it was subjected to digestion.

[0039] It can be seen that the wheat germ protein hydrolysate obtained in the present application can be used for preparing various functional foods, food ingredients or medicines, such as hypolipidemic foods, functional beverages, special medical use formula foods, hypolipidemic drugs, etc. The addition amount of the wheat germ protein in these products is more than 0.5 wt%, which can obviously inhibit the absorption of oil and fat.

[0040] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. The application of wheat germ protein hydrolysate in the preparation of products that inhibit oil absorption, characterized in that, The wheat germ protein hydrolysate contains peptides with a molecular weight of less than 1000 Da, a GRAVY value greater than 0, and an isoelectric point of less than 6.

2. The application of the wheat germ protein hydrolysate according to claim 1 in the preparation of products that inhibit oil absorption, characterized in that, The method for preparing the wheat germ protein hydrolysate includes the following steps: (1) Extraction of wheat germ protein: After crushing defatted wheat germ, add deionized water, adjust pH and temperature to extract protein, take the supernatant and add amylase to remove starch, adjust pH to 4.0 to precipitate protein, wash the precipitate with water, add deionized water to the precipitate, adjust pH to neutral, stir to dissolve, and obtain wheat germ protein solution. (2) Enzymatic hydrolysis: Dilute the wheat germ protein solution, adjust the pH and temperature, then add protease to the protein solution for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, inactivate the enzyme and centrifuge. The supernatant is the wheat germ protein hydrolysate. (3) Enrichment of functional peptides: Wheat germ protein hydrolysate was processed by ultrafiltration membrane and macroporous resin respectively to enrich wheat germ protein hydrolysate.

3. The application of the wheat germ protein hydrolysate according to claim 2 in the preparation of products that inhibit oil absorption, characterized in that, In step (1), the ratio of wheat germ powder to deionized water is 1:10-1:30; the pH is 6-12; the temperature is 40-65℃; and the supernatant is obtained by filtration or centrifugation.

4. The application of the wheat germ protein hydrolysate according to claim 2 or 3 in the preparation of products that inhibit oil absorption, characterized in that, In step (1), the amylase is one or both of high-temperature α-amylase and β-amylase, the enzymatic hydrolysis pH is 7.0-5.0, the enzymatic hydrolysis temperature is 40-70℃, the enzymatic hydrolysis time is 30 min-3 h, and the addition amount is 2-50 U / mL; the water washing precipitation is performed twice.

5. The application of the wheat germ protein hydrolysate according to claim 2 in the preparation of products that inhibit oil absorption, characterized in that, In step (2), the concentration of the wheat germ protein after dilution is 5-15%; the pH is 7.0-10.0 and the temperature is 30-65℃.

6. The application of the wheat germ protein hydrolysate according to claim 2 or 5 in the preparation of products that inhibit oil absorption, characterized in that, In step (2), the protease is one or more of papain, alkaline protease, neutral protease, complex protease or flavor protease, and the amount of enzyme added is 2% based on the protein weight; the enzymatic hydrolysis time is 200-400 min; and the enzyme inactivation method is boiling in 100℃ water for 5-20 min.

7. The application of the wheat germ protein hydrolysate according to claim 2 in the preparation of products that inhibit oil absorption, characterized in that, In step (3), the ultrafiltration membrane is a tangential flow ultrafiltration membrane with a molecular weight cutoff of 1000-5000 Da, and the retentate is treated with macroporous resin. The macroporous resin is a non-polar macroporous resin, and the desorption solution is a 25-85% ethanol solution. After the ethanol solution of the desorbed enzyme hydrolysate is vacuum deethanoled, it is spray-dried to obtain wheat germ enzyme hydrolysate.

8. The application of the wheat germ protein hydrolysate according to claim 1 in the preparation of products that inhibit oil absorption, characterized in that, The product that inhibits lipid absorption is a food or a medicine; the food is a general food, a health food, or a food for special medical purposes, and the medicine is a lipid-lowering drug.

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