A soybean peptide fermentation product and preparation method thereof

Abstract

The present invention discloses a soybean peptide fermentation product and a preparation method thereof. The soybean peptide fermentation product is obtained by (1) enzymatic hydrolysis of whey protein powder; (2) feeding and sterilizing fermentation raw materials; (3) fermentation; (4) sterilization, separation and concentration; and (5) drying to obtain a paste soybean peptide fermentation product and a powder soybean peptide fermentation product. The soybean peptide fermentation product of the present invention contains a variety of active antimicrobial peptides and antibacterial components such as organic acids, and has antibacterial and antiseptic effects. At the same time, the various components can extend the shelf life of the applied food under the synergistic effect. In addition, the soybean peptide fermentation product of the present invention also has a variety of fermented flavor substances, such as flavor peptides, etc., which give the food a special flavor.

Description

Technical Field

[0001] The invention belongs to the technical fields of fermentation engineering, enzyme engineering and food processing, and specifically relates to a soybean peptide fermentation product and a preparation method thereof. Background Art

[0002] Food safety is a hot topic of widespread concern worldwide, and microbial contamination is one of the main causes of food safety problems. Microbial contamination can cause food to spoil, thus causing food poisoning and posing serious threats to food safety. Preservatives are an effective way to solve microbial contamination. At present, chemical preservatives such as sodium dehydroacetate, sodium benzoate, potassium sorbate, etc. are mainly used in food production. However, excessive use of chemical preservatives can cause microbial resistance, chemical preservative residues, and changes in food quality. As people pay more and more attention to the freshness and nutritional value of food, higher and higher standards are put forward for the edible quality of food, and the use of food preservatives is becoming more and more stringent. Therefore, there is an urgent need to develop safe, hygienic, natural, non-toxic, efficient, broad-spectrum, and stable food preservatives. Summary of the invention

[0003] The present invention aims to provide a method for preparing soybean peptide fermentation product.

[0004] The present invention also aims to provide a soybean peptide fermentation product prepared by the above method.

[0005] The above-mentioned object of the present invention can be achieved by the following technical scheme: A method for preparing soybean peptide fermentation product comprises the following steps:

[0006] (1) Enzymatic hydrolysis of whey protein powder: adding water to the whey protein powder, adjusting the pH value to 6-8, adding microbial composite protease and papain, performing enzymatic hydrolysis at a temperature of 40-60° C. for 2-8 hours, heating up after enzymatic hydrolysis to inactivate the enzyme, and cooling to room temperature to obtain a whey protein powder enzymatic hydrolyzate;

[0007] (2) Feeding and sterilizing fermentation raw materials: Soy peptide paste, whey protein powder hydrolysate, glucose, dipotassium hydrogen phosphate and water are placed in a fermentation container, heated and sterilized, and then cooled to obtain a sterilized fermentation medium;

[0008] (3) Fermentation: Add lactic acid bacteria starter culture to sterile fermentation medium, introduce sterile nitrogen and stir to ferment for 72-168 hours at 25-35° C., with a stirring speed of 30-100 RPM, aeration volume of 0.1-0.3 VVM, and pressure of 0.02-0.04 MPa;

[0009] (4) Sterilization, separation and concentration: After the fermentation is completed, the temperature is first raised for sterilization and then solid-liquid separation is performed. The separated liquid is concentrated to obtain the soybean peptide fermentation product.

[0010] Preferably, the mass ratio of the whey protein powder to water in step (1) is 1:3-5.

[0011] Preferably, in step (1), sodium hydroxide or hydrochloric acid is used to adjust the pH value to 6-8.

[0012] Preferably, the amount of the microbial composite protease in step (1) is 0.1-1.5% of the total mass of whey protein powder and water, and the microbial composite protease is a composite of alkaline protease, neutral protease and acidic protease; the amount of papain is 0.1-1.0% of the total mass of whey protein powder and water; after enzymolysis in step (1), the temperature is raised to 85-90° C. and kept warm for 30-60 minutes to inactivate the enzyme.

[0013] Preferably, the microbial composite protease is a commercial enzyme preparation, and the mass percentage ratio of alkaline protease: neutral protease: acidic protease in the microbial composite protease is 70-50:20-45:10-5.

[0014] Preferably, the papain is a commercial protease, mainly referring to a biological enzyme preparation extracted from papaya fruit latex.

[0015] Preferably, the soybean peptide paste, whey protein powder hydrolysate, glucose, dipotassium hydrogen phosphate and water in step (2) are composed of the following mass percentages: 1-9% soybean peptide paste, 4-20% whey protein powder hydrolysate, 1-6% glucose, 0.1-0.6% dipotassium hydrogen phosphate, and the remainder water.

[0016] The soybean peptide paste in the present invention is a peptide product made from soybean meal as raw material through processes such as enzymatic hydrolysis, extraction and concentration. The soybean peptide paste is rich in active peptides, which can not only enhance the flavor of food, but also provide nutrients for biological growth. When soybean peptide paste is used as a fermentation raw material, it can promote the growth of microorganisms and provide precursors for the generation of fermentation products. It is a fermentation raw material with development potential. Patent CN102138627B "A plant-derived flavor peptide and its preparation method" discloses a preparation method of soybean peptide paste. The present invention can use the soybean peptide paste prepared by the patented method as a raw material to prepare soybean peptide fermentation products.

[0017] Preferably, in step (2), after heating to 121° C. for sterilization for 30-60 minutes, the medium is cooled to 25-35° C. within 30-60 minutes to obtain a sterilized fermentation medium.

[0018] Preferably, the amount of the lactic acid bacteria starter in step (3) is 5-15% of the total mass of the sterilized fermentation medium; the lactic acid bacteria starter in step (3) is Lactiplantibacillus plantarum and Lactococcus lactis subsp. lactis, the plant lactic acid bacteria starter accounts for 40-80% of the total mass of the lactic acid bacteria starter, and the Lactococcus lactis subsp. lactis accounts for 20-60% of the total mass of the lactic acid bacteria starter.

[0019] Preferably, in step (4), the temperature is first raised to 100-110° C. and maintained for 30-60 minutes for sterilization.

[0020] Preferably, in step (4), the separated liquid is concentrated at 50-70° C. to a solid content of 60-70% by weight, thereby obtaining a paste of soybean peptide fermentation product.

[0021] Preferably, in step (4), the separated liquid is concentrated at 50-70°C to a solid content of 30% by weight, and the concentrated material is spray-dried under the drying conditions of an inlet air temperature of 180-260°C and an outlet air temperature of 80-130°C to obtain a powdered soybean peptide fermentation product.

[0022] The soybean peptide fermentation product of the present invention has two states: paste and powder.

[0023] The invention uses soybean peptide paste, whey protein powder enzymatic hydrolysate and glucose as main raw materials, two edible lactic acid bacteria, plantarum lactobacillus and lactococcus lactis subsp. lactis, as fermentation agents, and prepares soybean peptide fermentation products through fermentation, filtration, concentration and other processing steps.

[0024] The second object of the present invention can be achieved by the following technical solution: a soybean peptide fermentation product is prepared by the above method.

[0025] Preferably, in the soybean peptide fermentation product, the peptide content (based on dry matter, %) is ≥8%, the total acid (based on acetic acid, %) is ≥8% (paste), and the total acid (based on acetic acid, %) is ≥12% (powder).

[0026] The soybean peptide fermentation product of the present invention has the function of imparting flavor to food and also has the antibacterial function of inhibiting bacterial growth.

[0027] The present invention has the following advantages:

[0028] (1) The soybean peptide fermentation product of the present invention contains a variety of organic acids, such as lactic acid and acetic acid, which can inhibit the synthesis of intracellular macromolecules, increase osmotic pressure to rupture cells, and destroy lipopolysaccharide structure to destroy cell membrane stability and integrity by changing the pH gradient inside and outside the microorganisms, thereby playing an antibacterial role. Organic acids are also an important type of flavor substances that can give food a sour flavor and are often used in food production;

[0029] (2) The soybean peptide fermentation product of the present invention is a natural lactic acid bacteria fermentation product, which is rich in active peptides and organic acids, has good antibacterial properties, taste effects and nutritional value, conforms to the food development trend of "natural, nutritious and safe", is conducive to improving my country's food safety and food quality;

[0030] (3) The active peptide in the soybean peptide fermentation product of the present invention is a small molecule biologically active substance, which is composed of a variety of amino acids linked to each other. The active peptides composed of different amino acids have different characteristics, such as antimicrobial peptides that can inhibit the growth of microorganisms, flavor peptides that can present flavors, etc. Antimicrobial peptides are a type of active peptides with antibacterial properties. The hydrophilic and hydrophobic ends of the amino acid chain of antimicrobial peptides can pass through the cell membrane of microorganisms, causing the cell membrane to break, the intracellular substances to leak, and cause the death of microorganisms. Antimicrobial peptides can also inhibit the reproduction of microorganisms by inhibiting the formation of cell walls, inhibiting the synthesis of intracellular macromolecules, inhibiting enzyme activity, activating autolytic enzymes, etc. Flavor peptides are small peptide compositions with a molecular weight of 1000 to 5000 Da, which have the characteristics of mellowness and strong extension, and can enhance the richness of food, improve the flavor of food, and increase the nutritional value of food;

[0031] (4) The soybean peptide fermentation product of the present invention contains a variety of active antimicrobial peptides and antibacterial components such as organic acids, and has antibacterial and antiseptic effects. At the same time, the various components can extend the shelf life of the applied food under the synergistic effect. In addition, the soybean peptide fermentation product of the present invention also has a variety of fermented flavor substances, such as flavor peptides, etc., which give the food a special flavor. The soybean peptide fermentation product of the present invention not only has antibacterial and antiseptic effects and enhances the flavor of food, but also plays a role in extending the shelf life of food;

[0032] (5) The soybean peptide fermentation product prepared with soybean peptide paste, whey protein powder hydrolysate and glucose as raw materials of the present invention can be used in various applications in the food industry, such as in the preparation of products with antibacterial and antiseptic functions, enhancing food flavor and extending the shelf life of food. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the production process of the soybean peptide fermentation product in Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with specific examples. The following examples are only for illustrative purposes and are not to be construed as limiting the present invention. Unless otherwise specified, the raw materials used in the following examples are conventional commercially available or commercially available raw materials, and unless otherwise specified, the methods and equipment used in the following examples are conventional methods and equipment used in the art.

[0035] Example 1

[0036] Soybean peptide fermentation paste

[0037] Main raw materials: soybean peptide paste, whey protein powder and glucose.

[0038] like Figure 1 As shown, the preparation method of the paste soybean peptide fermentation product is:

[0039] (1) Enzymatic hydrolysis of whey protein powder: adding water to the whey protein powder in a material-water ratio of 1:3, adding sodium hydroxide or hydrochloric acid to adjust the pH to 7.0, adding 0.1% of the total mass of the material water microbial composite protease (alkaline protease: neutral protease: acidic protease = 70:20:10) and 0.1% of the total mass of the material water papain, enzymolyzing at a temperature of 50° C. for 2 hours, heating to 90° C., keeping the temperature for 30 minutes, inactivating the enzyme, and cooling to room temperature to obtain a whey protein powder enzymolyzate;

[0040] (2) Adding fermentation raw materials and sterilizing: Adding fermentation raw materials and water into the fermentation tank, the total amount of fermentation raw materials and water is 100% (by mass percentage), soybean peptide paste is 9%, whey protein powder enzymatic hydrolysate is 4%, glucose is 5%, dipotassium hydrogen phosphate is 0.3%, and the balance is water. After adding the fermentation raw materials and water, the temperature is raised to 121° C. and sterilized for 30 minutes. After sterilization, it is cooled to 35° C. within 30 minutes to obtain a sterilized fermentation medium;

[0041] (3) Fermentation: A lactic acid bacteria starter culture accounting for 5% of the total mass of the sterilized fermentation medium was added, and the culture was stirred and fermented for 72 hours at 35° C. with sterile nitrogen gas introduced therein, the stirring speed was 30 RPM, the ventilation volume was 0.1 VVM, and the tank pressure was maintained at 0.02 MPa, wherein the lactic acid bacteria starter culture included Lactiplantibacillus plantarum accounting for 40% of the total mass of the culture and Lactococcus lactis subsp. lactis accounting for 60% of the total mass of the culture;

[0042] (4) Sterilization and separation: After the fermentation is completed, the temperature is raised to 100°C and maintained for 60 minutes for sterilization. After cooling, solid-liquid separation is performed by filtration;

[0043] (5) Concentration: The separated liquid is concentrated at 70° C. until the solid content is 60% by weight, thereby obtaining a paste of soybean peptide fermentation product.

[0044] Example 2

[0045] The difference from Example 1 is that in step (2), the fermentation raw materials are fed and sterilized: the fermentation raw materials and water are fed into the fermentation tank, the total amount of the fermentation raw materials and water is 100% (by mass percentage), the soybean peptide paste is 5%, the whey protein powder enzymatic hydrolysate is 12%, the glucose is 3%, the dipotassium hydrogen phosphate is 0.4%, and the balance is water.

[0046] Example 3

[0047] Powdered soybean peptide fermentation

[0048] Main ingredients: soybean peptide paste, whey protein powder and glucose

[0049] like Figure 1 As shown, the preparation method of powdered soybean peptide fermentation product is:

[0050] (1) Enzymatic hydrolysis of whey protein powder: adding water to the whey protein powder in a material-water mass ratio of 1:5, adding sodium hydroxide or hydrochloric acid to adjust the pH to 8, adding 1.0% of the total mass of the material water microbial composite protease (alkaline protease: neutral protease: acidic protease = 50:45:5) and 0.5% of the total mass of the material water papain, performing enzymatic hydrolysis at a temperature of 45° C. for 8 hours, raising the temperature to 85° C., keeping the temperature for 60 minutes, inactivating the enzyme, and cooling to room temperature to obtain a whey protein powder enzymatic hydrolyzate;

[0051] (2) Fermentation raw material feeding and sterilization: Fermentation raw materials and water are fed into the fermentation tank, the total amount of fermentation raw materials and water is 100% (by mass percentage), soybean peptide paste is 7%, whey protein powder enzymatic hydrolysate is 20%, glucose is 3%, dipotassium hydrogen phosphate is 0.5%, and the balance is water. After the fermentation raw materials and water are fed, the temperature is raised to 121° C. and sterilized for 60 minutes. After sterilization, the medium is cooled to 30° C. within 50 minutes to obtain a sterilized fermentation medium;

[0052] (3) Fermentation: The sterilized fermentation medium is inoculated with a lactic acid bacteria starter accounting for 10% of its total mass, and sterile nitrogen is introduced at 30° C. and stirred for fermentation for 120 hours, with a stirring speed of 50 RPM, a ventilation volume of 0.2 VVM, and a tank pressure maintained at 0.04 MPa, wherein the lactic acid bacteria starter includes Lactobacillus plantarum accounting for 80% of its total mass and Lactococcus lactis subsp. lactis accounting for 20% of its total mass;

[0053] (4) Sterilization and separation: After the fermentation is completed, the temperature is raised to 105°C and maintained for 30 minutes for sterilization. After cooling, solid-liquid separation is performed by filtration;

[0054] (5) Concentration: Concentrating the separated liquid at 65° C. until the solid content is 30% by weight;

[0055] (6) Drying: The concentrated material is spray dried under the conditions of an inlet air temperature of 200°C and an outlet air temperature of 100°C to obtain a powdered soybean peptide fermentation product.

[0056] Example 4

[0057] The difference from Example 3 is that the amount of the lactic acid bacteria starter in step (3) is 12% of the total mass of the sterilized fermentation medium.

[0058] The soybean peptide fermentation product of the present invention contains a variety of active antimicrobial peptides and antibacterial components such as organic acids, and has antibacterial and antiseptic effects. At the same time, the various components can extend the shelf life of the applied food under the synergistic effect. In addition, the soybean peptide fermentation product of the present invention also has a variety of fermented flavor substances, such as flavor peptides, etc., which give the food a special flavor. The soybean peptide fermentation product of the present invention not only has antibacterial and antiseptic effects and enhances the flavor of food, but also plays a role in extending the shelf life of food.

[0059] In the preparation method of the above-mentioned soybean peptide fermentation product, it is recommended but not limited to: microbial composite protease refers to a composite of alkaline protease, neutral protease and acidic protease prepared by microorganisms through fermentation; papain refers to a biological enzyme preparation extracted from papaya fruit latex; the equipment used in the whey protein powder enzymatic hydrolysis process is an enzymatic hydrolysis tank with a stirrer; the equipment used in the fermentation process is an anaerobic fermentation tank; the equipment used in the separation process is a continuous or intermittent separator; the equipment used in the concentration process is a vacuum concentrator; the equipment used in the drying process is a centrifugal or pressure spray dryer.

[0060] The above embodiments are only used to illustrate the present invention, and the protection scope of the present invention is not limited to the above embodiments. A person skilled in the art can achieve the purpose of the present invention based on the above disclosure of the present invention, and any improvement and deformation based on the concept of the present invention shall fall within the protection scope of the present invention, and the specific protection scope shall be subject to the claims.

Claims

1. A method for preparing a soybean peptide fermentation product, characterized in that: The following steps are involved: (1) Enzymatic hydrolysis of whey protein powder: adding water to the whey protein powder, adjusting the pH value to 6-8, adding microbial composite protease and papain, performing enzymatic hydrolysis at a temperature of 40-60° C. for 2-8 hours, heating up after enzymatic hydrolysis to inactivate the enzyme, and cooling to room temperature to obtain a whey protein powder enzymatic hydrolyzate; (2) Feeding and sterilizing fermentation raw materials: Soy peptide paste, whey protein powder hydrolysate, glucose, dipotassium hydrogen phosphate and water are placed in a fermentation container, heated and sterilized, and then cooled to obtain a sterilized fermentation medium; (3) Fermentation: Add lactic acid bacteria starter culture to sterile fermentation medium, introduce sterile nitrogen and stir to ferment for 72-168 hours at 25-35° C., with a stirring speed of 30-100 RPM, aeration volume of 0.1-0.3 VVM, and pressure of 0.02-0.04 MPa; (4) Sterilization, separation and concentration: After the fermentation is completed, the temperature is first raised for sterilization and then solid-liquid separation is performed. The separated liquid is concentrated to obtain the soybean peptide fermentation product.

2. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: The mass ratio of the whey protein powder to water in step (1) is 1:3-5; and the pH value is adjusted to 6-8 by using sodium hydroxide or hydrochloric acid in step (1).

3. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: The amount of the microbial composite protease in step (1) is 0.1-1.5% of the total mass of whey protein powder and water, and the microbial composite protease is a composite of alkaline protease, neutral protease and acidic protease; the amount of papain is 0.1-1.0% of the total mass of whey protein powder and water.

4. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: After the enzymatic hydrolysis in step (1), the temperature is raised to 85-90° C. and kept warm for 30-60 minutes to inactivate the enzyme.

5. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: The soy peptide paste, whey protein powder enzymolysate, glucose, dipotassium hydrogen phosphate and water in step (2) are composed of the following mass percentages: 1-9% soy peptide paste, 4-20% whey protein powder enzymolysate, 1-6% glucose, 0.1-0.6% dipotassium hydrogen phosphate, and the remainder water.

6. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: In step (2), the temperature is raised to 121° C. for sterilization for 30-60 minutes, and then cooled to 25-35° C. within 30-60 minutes to obtain a sterilized fermentation medium.

7. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: The amount of the lactic acid bacteria fermentation agent in step (3) is 5-15% of the total mass of the sterilized fermentation medium; the lactic acid bacteria fermentation agent comprises plant lactobacillus and lactococcus lactis subsp. lactis, wherein the plant lactobacillus accounts for 40-80% of the total mass of the lactic acid bacteria fermentation agent, and the lactococcus lactis subsp. lactis accounts for 20-60% of the total mass of the lactic acid bacteria fermentation agent.

8. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: In step (4), the temperature is first raised to 100-110° C. and maintained for 30-60 minutes for sterilization; in step (4), the separated liquid is concentrated at 50-70° C. to a solid content of 60-70% by weight, thereby obtaining a paste of soybean peptide fermentation product.

9. The method for preparing soybean peptide fermentation product according to claim 1, characterized in that: In step (4), the separated liquid is concentrated at 50-70° C. to a solid content of 30% by weight, and the concentrated material is spray-dried under the drying conditions of an inlet air temperature of 180-260° C. and an outlet air temperature of 80-130° C. to obtain a powdered soybean peptide fermentation product.

10. A soybean peptide fermentation product, characterized in that: The method is prepared by any one of claims 1 to 9.

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