A raw material processing method for preparing chickpea polypeptide

Abstract

The present invention belongs to the technical field of chickpea polypeptide preparation, and specifically relates to a raw material processing method for preparing chickpea polypeptide. The method comprises the following steps: (1) preparing chickpea powder; (2) performing ultrasound-assisted extraction; (3) preparing a first fermentation product; (4) preparing a second fermentation product; (5) purifying the second fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 15-20KDa, at a pressure of 0.1-0.2MPa, a temperature of 20-25°C, and a flow rate of 30-40m / s to obtain a polypeptide extraction solution; (6) concentrating the polypeptide extraction solution using a regenerated cellulose flat membrane with a molecular weight cutoff of 0.5-1KDa, with a concentration multiple of 6-8 times to obtain a concentrate; (7) centrifuging the concentrate, freeze-drying, and obtaining a chickpea polypeptide. The chickpea polypeptide prepared by the present invention has a high yield and good broad-spectrum antibacterial property.

Description

Technical Field

[0001] The invention belongs to the technical field of chickpea polypeptide preparation, and particularly relates to a raw material processing method for preparing chickpea polypeptide. Background Art

[0002] Chickpea (scientific name: Cicerarietinum), also known as chicken heart pea, chickpea or Egyptian bean, is an important edible legume crop belonging to the legume family. Chickpea is rich in bioactive substances, such as flavonoids, saponins, high-quality protein, etc. In particular, the protein in chickpea is superior to many other cereals and legume proteins in all aspects. At present, the chickpea products on the market have problems such as simple types, shallow processing, insufficient functional characteristics, and unstable quality. Therefore, it is urgent to develop the health and medicinal value of chickpeas, use new process technologies, and invest in new equipment to develop and produce high-value-added chickpea peptides and other high-end products to meet the diverse market needs.

[0003] Chickpea peptides are small molecule peptide compounds extracted from chickpea protein. These peptides have multiple biological activities and are widely used in food, medicine, cosmetics and other fields. At present, chickpea peptides are mainly produced by enzymatic hydrolysis, which has problems such as high cost and a certain bitterness of the product, while the existing fermentation process has the problem of low yield.

[0004] As a possible alternative to traditional antibiotics, antimicrobial peptides are becoming a hot topic of concern due to their superior properties. Antimicrobial peptides are active peptides that are widely found in natural organisms and have biological functions such as antibacterial, antiviral, antiparasitic, and immunity-enhancing. They have broad-spectrum antimicrobial activity and can not only inhibit a variety of bacteria or fungi, but can even inhibit tumor cells in animals without harming normal cells. Chickpeas are rich in peptide components, and their antibacterial activity is increasingly being studied. However, the antibacterial effect of chickpea peptides currently on the market is not ideal.

[0005] Therefore, there is an urgent need for a method for preparing chickpea polypeptides with high product yield and good antibacterial effect. Summary of the invention

[0006] The purpose of the present invention is to provide a raw material processing method for preparing chickpea polypeptide.

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

[0008] A method for processing raw materials for preparing chickpea polypeptides comprises the following steps:

[0009] (1) drying and crushing chickpea pods to obtain chickpea powder;

[0010] (2) mixing chickpea powder with deionized water, adjusting the pH to 8.6-9.0, and performing ultrasonic-assisted extraction. After the extraction, adjusting the pH to neutral to obtain a fermentation raw material;

[0011] (3) adding composite bacteria to the fermentation raw material, performing anaerobic fermentation, and sterilizing to obtain a first fermentation product;

[0012] (4) adding Lactobacillus bulgaricus to the first fermentation product, performing anaerobically fermentation at 35-40° C. for 3-5 h, sterilizing, continuously adding Lactobacillus helveticus, performing anaerobically fermentation at 35-40° C. for 9-11 h, sterilizing, continuously adding Lactobacillus acidophilus, performing anaerobically fermentation at 35-40° C. for 6-8 h, sterilizing, and obtaining a second fermentation product;

[0013] (5) purifying the second fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 15-20 KDa at a pressure of 0.1-0.2 MPa, a temperature of 20-25° C., and a flow rate of 30-40 m / s to obtain a polypeptide extract solution;

[0014] (6) Concentrating the polypeptide extract solution using a regenerated cellulose flat membrane with a molecular weight cutoff of 0.5-1 KDa at a pressure of 0.1-0.2 MPa, a temperature of 20-25° C., and a flow rate of 35-45 m / s, with the concentration multiple being 6-8 times to obtain a concentrate;

[0015] (7) The concentrate is centrifuged and freeze-dried to obtain chickpea polypeptide.

[0016] Furthermore, in the step (1), the chickpea pods are dried and crushed to less than 200 meshes to obtain chickpea powder.

[0017] Furthermore, the conditions for ultrasonic assisted extraction in step (2) are: ultrasonic assisted extraction at 40-45°C and 100-120W for 20-30 minutes.

[0018] Furthermore, in the step (2), chickpea powder is mixed with deionized water in a weight ratio of 1:(12-15).

[0019] Furthermore, in step (2), the pH is adjusted to 8.6-9.0 using 6-8 wt% NaOH solution.

[0020] Furthermore, in step (2), the pH value is adjusted to neutral using 8-10 wt % citric acid solution.

[0021] Furthermore, the composite bacteria in step (3) include Lactobacillus casei, Lactobacillus brevis and Bifidobacterium longum.

[0022] Furthermore, the amount of Lactobacillus casei added was 10 10 -10 11CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 9 -10 10 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 8 -10 9 CFU / mL fermentation raw material.

[0023] The invention can improve the yield of chickpea polypeptides by first extracting chickpea powder and then fermenting it with composite bacteria. The analysis shows that the cavitation effect of ultrasound can effectively destroy the cell wall structure, increase the contact area between protein and solvent, and thus improve the extraction efficiency of protein; during the fermentation process of composite bacteria, the protein released after ultrasonic extraction can be further hydrolyzed and decomposed into smaller polypeptides.

[0024] Furthermore, the fermentation conditions of step (3) are: fermentation temperature 30-40° C., and fermentation 10-12 hours.

[0025] Furthermore, the dosage of Lactobacillus bulgaricus in step (4) is 10 6 -10 7 cfu / mL first fermentation product; the dosage of Lactobacillus helveticus is 10 8 -10 9 cfu / mL first fermentation product; the dosage of Lactobacillus acidophilus is 10 10 -10 11 cfu / mL first fermentation product.

[0026] The present invention uses specific bacteria to perform gradient fermentation on the basis of one fermentation. Through the synergistic effect of two fermentations, the spectrum antibacterial property of chickpea polypeptide can be improved, and the antibacterial types are more and wider. The dual fermentation strategy can make full use of the metabolic capacity and enzymatic characteristics of different microorganisms, produce diversified bioactive substances, and enhance the antibacterial effect of polypeptides.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0028] 1. The present invention uses Xinjiang chickpea as raw material, innovates the traditional peptide production process, and uses microbial fermentation to prepare chickpea peptides. This method of producing chickpea peptides can not only solve the high cost of enzymatic peptide production, but also greatly improve the problem of low yield of microbial fermentation. The present invention fully utilizes Xinjiang chickpeas, promotes the deep processing of agricultural and sideline products, promotes the circular economy, and maintains human health.

[0029] 2. The present invention can improve the yield of chickpea polypeptide by first extracting chickpea powder and then fermenting it with composite bacteria.

[0030] 3. The present invention uses specific bacteria to perform gradient fermentation on the basis of one fermentation. Through the synergistic effect of the two fermentations, the spectrum antibacterial property of the chickpea polypeptide can be improved, and the antibacterial types are more and wider. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The raw materials used in the following examples of the present invention are all commercially available products:

[0033] Bacillus coagulans, number: SHBCCD10638, was purchased from Shanghai Microbiological Collection Center.

[0034] Lactobacillus paracasei, number: SHBCCD51555, purchased from Shanghai Collection of Microorganisms Center,

[0035] Lactobacillus plantarum, number: CCTCCAB2010210, was purchased from China Center for Type Culture Collection.

[0036] Bifidobacterium longum, number: CCTCCHB20082718, deposited in China Center for Type Culture Collection.

[0037] Lactobacillus bulgaricus, number: CCTCCCB20082295; purchased from China Center for Type Culture Collection.

[0038] Lactobacillus brevis, number: SHBCCD14346, was purchased from Shanghai Microbiological Collection Center.

[0039] Lactobacillus helveticus, number: CCTCCAB2010205; purchased from China Center for Type Culture Collection.

[0040] Lactobacillus casei, number: SHBCCD24737, was purchased from Shanghai Microbiological Collection Center.

[0041] Lactobacillus acidophilus, number: CCTCCAB2010208, was purchased from China Center for Type Culture Collection.

[0042] The chickpeas used were Muli chickpeas, from Muli Kazakh Autonomous County, Xinjiang Uygur Autonomous Region.

[0043] Example 1

[0044] This embodiment provides a method for processing raw materials for preparing chickpea polypeptides, comprising the following steps:

[0045] (1) drying chickpea pods and crushing them to less than 200 meshes to obtain chickpea powder;

[0046] (2) Mixing chickpea powder and deionized water in a weight ratio of 1:13, adjusting the pH to 9.0 with a 7wt% NaOH solution, and ultrasonically assisted extraction, wherein the ultrasonic assisted extraction conditions are: ultrasonic assisted extraction at 42°C and 110W for 25 minutes; after completion, adjusting the pH to neutral with a 9wt% citric acid solution to obtain a fermentation raw material;

[0047] (3) adding composite bacteria to the fermentation raw material, performing anaerobic fermentation at a temperature of 35° C. for 11 h, and sterilizing to obtain a first fermentation product; the composite bacteria include Lactobacillus casei, Lactobacillus brevis and Bifidobacterium longum; the addition amount of Lactobacillus casei is 10 11 CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 10 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 8 CFU / mL fermentation raw material;

[0048] (4) adding Lactobacillus bulgaricus to the first fermentation product, anaerobic fermentation at 37° C. for 4 h, sterilization, continuing to add Lactobacillus helveticus, anaerobic fermentation at 37° C. for 10 h, sterilization, continuing to add Lactobacillus acidophilus, anaerobic fermentation at 37° C. for 7 h, sterilization, to obtain a second fermentation product; the amount of Lactobacillus bulgaricus is 10 7 cfu / mL first fermentation product; the dosage of Lactobacillus helveticus is 10 9 cfu / mL first fermentation product; the dosage of Lactobacillus acidophilus is 10 10 cfu / mL first fermentation product;

[0049] (5) purifying the second fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 18 KDa at a pressure of 0.1 MPa, a temperature of 25° C., and a flow rate of 35 m / s to obtain a polypeptide extract solution;

[0050] (6) The polypeptide extract solution was concentrated by using a regenerated cellulose flat membrane with a molecular weight cutoff of 0.5 KDa at a pressure of 0.2 MPa, a temperature of 25° C., and a flow rate of 40 m / s, with a concentration multiple of 7 times to obtain a concentrate;

[0051] (7) The concentrate is centrifuged and freeze-dried to obtain chickpea polypeptide.

[0052] Example 2

[0053] This embodiment provides a method for processing raw materials for preparing chickpea polypeptides, comprising the following steps:

[0054] (1) drying chickpea pods and crushing them to less than 200 meshes to obtain chickpea powder;

[0055] (2) Mixing chickpea powder and deionized water in a weight ratio of 1:12, adjusting the pH to 8.6 with 8wt% NaOH solution, and ultrasonic-assisted extraction, wherein the ultrasonic-assisted extraction conditions are: ultrasonic-assisted extraction at 45°C and 100W for 30 minutes; after completion, adjusting the pH to neutral with 8wt% citric acid solution to obtain a fermentation raw material;

[0056] (3) adding composite bacteria to the fermentation raw material, performing anaerobic fermentation at a temperature of 40° C. for 10 h, and sterilizing to obtain a first fermentation product; the composite bacteria include Lactobacillus casei, Lactobacillus brevis and Bifidobacterium longum; the addition amount of Lactobacillus casei is 10 10 CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 9 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 9 CFU / mL fermentation raw material;

[0057] (4) Adding Lactobacillus bulgaricus to the first fermentation product, anaerobic fermentation at 40° C. for 5 h, sterilization, continuing to add Lactobacillus helveticus, anaerobic fermentation at 40° C. for 9 h, sterilization, continuing to add Lactobacillus acidophilus, anaerobic fermentation at 40° C. for 6 h, sterilization, to obtain a second fermentation product; the amount of Lactobacillus bulgaricus is 10 7 cfu / mL first fermentation product; the dosage of Lactobacillus helveticus is 10 9 cfu / mL first fermentation product; the dosage of Lactobacillus acidophilus is 10 11 cfu / mL first fermentation product;

[0058] (5) purifying the second fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 20 KDa at a pressure of 0.1 MPa, a temperature of 25° C., and a flow rate of 30 m / s to obtain a polypeptide extract solution;

[0059] (6) The polypeptide extract solution was concentrated using a regenerated cellulose flat membrane with a molecular weight cutoff of 1 KDa at a pressure of 0.1 MPa, a temperature of 25° C., and a flow rate of 35 m / s, with a concentration multiple of 8 times to obtain a concentrate;

[0060] (7) The concentrate is centrifuged and freeze-dried to obtain chickpea polypeptide.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 1 is that no ultrasonic-assisted extraction is performed.

[0063] A method for processing raw materials for preparing chickpea polypeptides comprises the following steps:

[0064] (1) drying chickpea pods and crushing them to less than 200 meshes to obtain chickpea powder;

[0065] (2) mixing chickpea powder and deionized water in a weight ratio of 1:13 to obtain a fermentation raw material;

[0066] (3) adding composite bacteria to the fermentation raw material, performing anaerobic fermentation at a temperature of 35° C. for 11 h, and sterilizing to obtain a first fermentation product; the composite bacteria include Lactobacillus casei, Lactobacillus brevis and Bifidobacterium longum; the addition amount of Lactobacillus casei is 10 11 CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 10 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 8 CFU / mL fermentation raw material;

[0067] (4) adding Lactobacillus bulgaricus to the first fermentation product, anaerobic fermentation at 37° C. for 4 h, sterilization, continuing to add Lactobacillus helveticus, anaerobic fermentation at 37° C. for 10 h, sterilization, continuing to add Lactobacillus acidophilus, anaerobic fermentation at 37° C. for 7 h, sterilization, to obtain a second fermentation product; the amount of Lactobacillus bulgaricus is 10 7 cfu / mL first fermentation product; the dosage of Lactobacillus helveticus is 10 9 cfu / mL first fermentation product; the dosage of Lactobacillus acidophilus is 10 10 cfu / mL first fermentation product;

[0068] (5) purifying the second fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 18 KDa at a pressure of 0.1 MPa, a temperature of 25° C., and a flow rate of 35 m / s to obtain a polypeptide extract solution;

[0069] (6) The polypeptide extract solution was concentrated by using a regenerated cellulose flat membrane with a molecular weight cutoff of 0.5 KDa at a pressure of 0.2 MPa, a temperature of 25° C., and a flow rate of 40 m / s, with a concentration multiple of 7 times to obtain a concentrate;

[0070] (7) The concentrate is centrifuged and freeze-dried to obtain chickpea polypeptide.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 1 is that only one fermentation is performed and the fermentation time is prolonged.

[0073] A method for processing raw materials for preparing chickpea polypeptides comprises the following steps:

[0074] (1) drying chickpea pods and crushing them to less than 200 meshes to obtain chickpea powder;

[0075] (2) Mixing chickpea powder and deionized water in a weight ratio of 1:13, adjusting the pH to 9.0 with a 7wt% NaOH solution, and ultrasonically assisted extraction, wherein the ultrasonic assisted extraction conditions are: ultrasonic assisted extraction at 42°C and 110W for 25 minutes; after completion, adjusting the pH to neutral with a 9wt% citric acid solution to obtain a fermentation raw material;

[0076] (3) adding composite bacteria to the fermentation raw material, performing anaerobic fermentation at a temperature of 35° C. for 32 h, and sterilizing to obtain a first fermentation product; the composite bacteria include Lactobacillus casei, Lactobacillus brevis and Bifidobacterium longum; the addition amount of Lactobacillus casei is 10 11 CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 10 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 8 CFU / mL fermentation raw material;

[0077] (4) purifying the first fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 18 KDa at a pressure of 0.1 MPa, a temperature of 25° C., and a flow rate of 35 m / s to obtain a polypeptide extract solution;

[0078] (5) The polypeptide extract solution was concentrated by using a regenerated cellulose flat membrane with a molecular weight cutoff of 0.5 KDa at a pressure of 0.2 MPa, a temperature of 25° C., and a flow rate of 40 m / s, with a concentration multiple of 7 times to obtain a concentrate;

[0079] (6) The concentrate is centrifuged and freeze-dried to obtain chickpea polypeptide.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that the composite bacteria include Bacillus coagulans, Lactobacillus paracasei and Lactobacillus plantarum; the addition amount of Bacillus coagulans is 10 11 CFU / mL fermentation raw material; the addition amount of Lactobacillus paracasei was 10 10 CFU / mL fermentation raw material; the addition amount of Lactobacillus plantarum is 10 8 CFU / mL fermentation raw material.

[0082] Comparative Example 4

[0083] The difference between this comparative example and Example 1 is that the addition amount of Lactobacillus casei is 10 8 CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 11 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 10 CFU / mL fermentation raw material.

[0084] Comparative Example 5

[0085] The difference between this comparative example and Example 1 is that Bacillus coagulans is added to the first fermentation product, anaerobic fermentation is carried out at 37°C for 4 hours, sterilization is performed, Lactobacillus paracasei is added, anaerobic fermentation is carried out at 37°C for 10 hours, sterilization is performed, Lactobacillus plantarum is added, anaerobic fermentation is carried out at 37°C for 7 hours, sterilization is performed, and a second fermentation product is obtained; the amount of Bacillus coagulans is 10 7 cfu / mL first fermentation product; the dosage of Lactobacillus paracasei is 10 9 cfu / mL first fermentation product; the dosage of Lactobacillus plantarum is 10 10 cfu / mL first fermentation product.

[0086] Comparative Example 6

[0087] The difference between this comparative example and Example 1 is that the dosage of Lactobacillus bulgaricus is 10 11 cfu / mL first fermentation product; the dosage of Lactobacillus helveticus is 10 8 cfu / mL first fermentation product; the dosage of Lactobacillus acidophilus is 10 7 cfu / mL first fermentation product.

[0088] Performance Testing

[0089] 1. Calculate the chickpea peptide yield of Examples 1-2 and Comparative Examples 1-6 using the formula: mass of chickpea polypeptide / mass of chickpea pods*100%. See Table 1 for the results.

[0090] Table 1 Peptide yield of chickpea

[0091] Chickpea peptide rate % Example 1 63.3 Example 2 62.5 Comparative Example 1 60.5 Comparative Example 2 55.1 Comparative Example 3 59.6 Comparative Example 4 60.2 Comparative Example 5 58.4 Comparative Example 6 60.7

[0092] 2. The chickpea polypeptides of Examples 1-2 and Comparative Examples 1-6 were used as samples for antibacterial test

[0093] Melt the agar medium and wait until its temperature drops to 46 ± 0.5 °C. Add the cultured bacterial suspension to make the concentration of the test bacterial suspension 5 × 10 5 cfu / mL, pour into a flat plate, 20mL / plate, and let it stand for 20min to solidify;

[0094] Use an agar puncher to punch holes with a diameter of 5 mm, 5 holes / dish, evenly distributed, with a distance of 25 mm between the centers of each sample and 15 mm from the edge of the plate;

[0095] The sample concentration was 100 mg / ml (100 mM). 20 μl of sample solution was added to each well. The plate was covered and placed in an incubator at 37°C for 30 min to allow the solution to be completely absorbed. The plate was inverted and cultured for 16 h. The diameter of the inhibition ring was measured with a vernier caliper.

[0096] The results are shown in Table 2-3.

[0097] Table 2 Antibacterial effect of chickpea peptides

[0098]

[0099] Table 3 Antibacterial effect of chickpea peptides

[0100]

[0101] From the above performance test results, it can be seen that the chickpea polypeptides of Examples 1-2 have a high yield and excellent antibacterial effect, especially the comprehensive performance of Example 1 is the most outstanding, which is mainly due to the synergistic effect between the components.

[0102] However, the comparative examples did not adopt the necessary technical solutions, resulting in corresponding performance tests that were significantly worse than those of the embodiments. In comparative example 1, ultrasonic-assisted extraction was not performed, and the yield and antibacterial activity decreased. In comparative example 2, secondary fermentation was not performed, and the antibacterial effect decreased significantly. In comparative examples 3 and 4, different types of bacteria and dosages were used for primary fermentation, and in comparative examples 5 and 6, different types of bacteria and dosages were used for secondary fermentation, and the yield and antibacterial activity decreased. The above experimental results further demonstrate the importance of the technical solutions defined in the present invention for its technical effects.

[0103] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for processing raw materials for preparing chickpea polypeptides, characterized in that: The following steps are involved: (1) drying and crushing chickpea pods to obtain chickpea powder; (2) mixing chickpea powder with deionized water, adjusting the pH to 8.6-9.0, and performing ultrasonic-assisted extraction. After the extraction, adjusting the pH to neutral to obtain a fermentation raw material; (3) adding composite bacteria to the fermentation raw material, performing anaerobic fermentation, and sterilizing to obtain a first fermentation product; (4) adding Lactobacillus bulgaricus to the first fermentation product, performing anaerobically fermentation at 35-40° C. for 3-5 h, sterilizing, continuously adding Lactobacillus helveticus, performing anaerobically fermentation at 35-40° C. for 9-11 h, sterilizing, continuously adding Lactobacillus acidophilus, performing anaerobically fermentation at 35-40° C. for 6-8 h, sterilizing, and obtaining a second fermentation product; (5) purifying the second fermentation product using a regenerated cellulose flat membrane with a molecular weight cutoff of 15-20 KDa at a pressure of 0.1-0.2 MPa, a temperature of 20-25° C., and a flow rate of 30-40 m / s to obtain a polypeptide extract solution; (6) Concentrating the polypeptide extract solution using a regenerated cellulose flat membrane with a molecular weight cutoff of 0.5-1 KDa at a pressure of 0.1-0.2 MPa, a temperature of 20-25° C., and a flow rate of 35-45 m / s, with the concentration multiple being 6-8 times to obtain a concentrate; (7) The concentrate is centrifuged and freeze-dried to obtain chickpea polypeptide.

2. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: In the step (1), the chickpea pods are dried and crushed to less than 200 meshes to obtain chickpea powder.

3. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: The conditions for ultrasonic assisted extraction in step (2) are: ultrasonic assisted extraction at 40-45°C and 100-120W for 20-30 minutes.

4. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: In the step (2), chickpea powder and deionized water are mixed in a weight ratio of 1:(12-15).

5. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: In the step (2), the pH is adjusted to 8.6-9.0 using 6-8 wt% NaOH solution.

6. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: In the step (2), 8-10 wt % citric acid solution is used to adjust the pH value to neutral.

7. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: The composite bacteria in step (3) include Lactobacillus casei, Lactobacillus brevis and Bifidobacterium longum.

8. The method for processing raw materials for preparing chickpea polypeptide according to claim 7, characterized in that: The amount of Lactobacillus casei added was 10 10 -10 11 CFU / mL fermentation raw material; the addition amount of Lactobacillus brevis was 10 9 -10 10 CFU / mL fermentation raw material; the addition amount of Bifidobacterium longum was 10 8 -10 9 CFU / mL fermentation raw material.

9. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: The fermentation conditions in step (3) are: fermentation temperature 30-40° C., and fermentation 10-12 hours.

10. The method for processing raw materials for preparing chickpea polypeptide according to claim 1, characterized in that: The dosage of Lactobacillus bulgaricus in step (4) is 10 6 -10 7 cfu / mL first fermentation product; the dosage of Lactobacillus helveticus is 10 8 -10 9 cfu / mL first fermentation product; the dosage of Lactobacillus acidophilus is 10 10 -10 11 cfu / mL first fermentation product.

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