Soybean flavor peptide as well as preparation method and application thereof

Abstract

The invention relates to the technical field of food processing, and particularly discloses soybean flavor peptide and a preparation method and application thereof. Aspergillus oryzae is selected as a leavening agent, a microbial endogenous enzyme generated by full fermentation of the aspergillus oryzae is utilized to cooperate with a compound enzyme preparation to perform combined action, abundant enzyme systems effectively perform enzymolysis on macromolecules such as protein, and related taste substances are provided for subsequent enzymolysis products; in the soybean flavor peptide prepared by enzyme hydrolysis and Maillard reaction, the contents of target peptide and target amino acid (umami peptide, umami amino acid and the like) are high; when the soybean flavor peptide is applied to the compound seasoning with the main function of increasing freshness, the freshness score can be increased by 0.5-2 times. In addition, on the basis of improving freshness, the taste richness of the food or the compound seasoning can be enhanced, and the aftertaste time is prolonged.

Description

Technical Field

[0001] This application relates to the technical field of food processing, and particularly relates to a soy flavor peptide, a preparation method thereof, and an application thereof. Background Art

[0002] Among the five flavors of "sweet, sour, bitter, salty, and umami", "umami" is a refreshing, mild, and pleasant taste, and has now become the taste standard pursued by people in diet.

[0003] Soybean is an important food crop with high protein content. Soybean meal or soybean cake is a by-product after its degreasing treatment, and both are often used in the fields of soy sauce brewing and feed industry. In order to improve the utilization rate of raw materials, soybean meal or soybean cake can efficiently utilize the protein in the raw materials through biological technology means. The amino acids and peptides generated after the degradation of protein play an important role in the flavor of food. Among them, umami amino acids, umami peptides, flavor-enhancing peptides, etc. all make important contributions to the umami of food.

[0004] Soy flavor peptide is a flavoring prepared from soybeans and / or defatted soybeans rich in high-quality protein through processes such as microbial fermentation, enzymatic hydrolysis, concentration, and sterilization. Macromolecular substances such as protein in the raw materials are hydrolyzed into small molecules such as amino acids and peptides under the combined action of endogenous enzymes and exogenous enzymes. These substances not only have the ability to present flavors themselves, but also act as reaction substrates in the technological stages prone to Maillard reaction. Soy flavor peptide has the functions of enhancing umami and flavor, enhancing the fullness in the mouth, and softening the taste of food, which is highly related to the release potential of amino acids and peptides during its enzymatic hydrolysis and biological fermentation process.

[0005] However, in the production processes disclosed in current research, due to the strong substrate specificity of exogenous proteases and the high requirements for enzymatic hydrolysis conditions, the protein is not fully hydrolyzed, the peptide yield is low, resulting in protein waste and weakening the umami-enhancing effect of soy flavor peptide.

[0006] Therefore, exploring the enzymatic hydrolysis ability of endogenous and exogenous enzymes, efficiently stimulating the dissolution of target amino acids and target peptides, and thus strengthening the advantages of soy flavor peptide is of great significance for the development and application in the field of flavor peptides. Summary of the Invention

[0007] The purpose of this application is to overcome the deficiencies of the above-mentioned existing technologies and provide a soy flavor peptide, a preparation method thereof, and an application thereof.

[0008] To achieve the above purpose, the technical solution adopted in this application is as follows:

[0009] This application provides a preparation method of a soy flavor peptide, including the following steps:

[0010] S1. Mix soybeans and / or defatted soybeans with water and cook, and after cooling, inoculate Aspergillus oryzae for fermentation to obtain a fermentation material;

[0011] S2. Mix the fermented material obtained in step S1 with water, and perform shearing treatment to obtain a slurry; then add a compound enzyme preparation to the slurry, stir and enzymatically hydrolyze it, and adjust the pH value to 6.0 - 6.4 to obtain an enzymatically hydrolyzed solution.

[0012] S3. Perform enzyme inactivation treatment on the enzymatically hydrolyzed solution, and then centrifuge it to obtain an enzymatically hydrolyzed supernatant.

[0013] S4. Concentrate, formulate, and sterilize the enzymatically hydrolyzed supernatant to prepare a soy - flavored peptide.

[0014] The compound enzyme preparation includes neutral protease, trypsin, bromelain, glutaminase, and aminopeptidase.

[0015] This application selects Aspergillus oryzae as the fermenting agent. Aspergillus oryzae is a microorganism rich in enzymes. The microbial endogenous enzymes produced by its full fermentation and the compound enzyme preparation act together. The rich enzyme system can effectively enzymatically hydrolyze macromolecules such as proteins, providing relevant flavor substances for the subsequent enzymatically hydrolyzed products. By using the above - mentioned method of combining endogenous and exogenous enzymes, the protein recovery rate can be increased by about 1 time, and relevant flavor substances can be provided for the subsequent enzymatically hydrolyzed products.

[0016] Moreover, this application adjusts the pH during the enzymatic hydrolysis process to 6.0 - 6.4 to determine the appropriate pH level for the combined hydrolysis of endogenous and exogenous enzymes, which can promote the hydrolysis of proteins by the enzyme system, release amino acids and peptides in the raw materials to the greatest extent, and the total amino acid content can be relatively increased by more than 31.49%, and the peptide nitrogen ratio can be relatively increased by 17.66%, thereby strengthening the umami - enhancing ability of the existing soy - flavored peptide.

[0017] As a preferred embodiment of the preparation method of the soy - flavored peptide described in this application, the compound enzyme preparation includes the following components in mass concentration:

[0018] Neutral protease 0.08 - 0.1%, trypsin 0.3 - 0.6%, bromelain 0.05 - 0.2%, glutaminase 0.1 - 0.2%, and aminopeptidase 0.1 - 0.4%.

[0019] This application uses the above - mentioned content of enzymes, which can enhance the protein hydrolysis ability, and then increase the ammonia nitrogen content, protein recovery rate, and peptide nitrogen ratio of the soy - flavored peptide; and can increase the content of total free amino acids and umami amino acids in the soy - flavored peptide, and then the umami feeling of the soy - flavored peptide is full and the aftertaste is long - lasting.

[0020] As a preferred embodiment of the preparation method of the soy - flavored peptide described in this application, in step S1, the mass ratio of the soybeans and / or defatted soybeans to water is 1:(1 - 2).

[0021] As a preferred embodiment of the method for preparing the soy - flavored peptide described in the present application, in step S1, the Aspergillus oryzae includes Aspergillus oryzae 3.042.

[0022] Biological fermentation is a process to promote enzyme production by microorganisms. Aspergillus oryzae secretes a rich enzyme system during fermentation. In this application, Aspergillus oryzae 3.042 with high - efficiency enzyme production is selected as the fermenting agent. The microbial endogenous enzymes and exogenous enzymes produced by its sufficient fermentation are used. The rich enzyme system can effectively hydrolyze macromolecules such as proteins, and fully hydrolyze the proteins in soybean cakes. By using the above - mentioned method of combining endogenous and exogenous enzymes, the protein recovery rate can be increased by about 1 time, providing relevant flavor substances for the subsequent enzymatic hydrolysate.

[0023] As a preferred embodiment of the method for preparing the soy - flavored peptide described in the present application, in step S1, the fermentation temperature is 26 - 38 °C, and the fermentation time is 34 - 40 h.

[0024] As a preferred embodiment of the method for preparing the soy - flavored peptide described in the present application, in step S1, the steaming temperature is 121 °C and the steaming time is 15 min, or the steaming temperature is 115 °C and the steaming time is 20 min.

[0025] As a preferred embodiment of the method for preparing the soy - flavored peptide described in the present application, in step S2, the mass ratio of the fermented material to water is 1:(2.5 - 4);

[0026] The rotation speed of shearing is 9000 - 11000 r / min, and the shearing time is 20 - 40 s.

[0027] As a preferred embodiment of the method for preparing the soy - flavored peptide described in the present application, in step S2, the enzymatic hydrolysis temperature is 50 - 60 °C, the enzymatic hydrolysis time is 10 - 12 h, and the pH of the enzymatic hydrolysate is adjusted to 6.0 - 6.4 when the enzymatic hydrolysis is carried out for 0.5 - 4 h.

[0028] In this application, biological fermentation is carried out first, then exogenous enzymes are added for enzymatic hydrolysis, and effective pH regulation is carried out during the enzymatic hydrolysis process, significantly enhancing the umami - enhancing ability of the soy - flavored peptide, and also significantly improving the richness of the overall flavor and the lasting aftertaste.

[0029] As a preferred embodiment of the method for preparing the soy - flavored peptide described in the present application, in step S3, the enzyme - inactivating temperature is 90 - 100 °C, and the enzyme - inactivating time is 15 - 20 min;

[0030] In step S3, the centrifugation speed is 8000 - 10000 r / min, and the centrifugation time is 20 - 30 min;

[0031] In step S4, concentration includes: subjecting the enzymatic hydrolysis supernatant to negative pressure concentration at a temperature of 55 - 65°C until the solid content is 55 - 65% to obtain a concentrate;

[0032] In step S4, the blending includes: adding table salt with a mass concentration of 0 - 8% (w / w) to the concentrate.

[0033] In step S4, the sterilization temperature is 90 - 100°C and the sterilization time is 0.5 - 2 h.

[0034] This application also provides a soy - flavored peptide prepared by the above - mentioned preparation method of soy - flavored peptide.

[0035] This application also provides the use of the above - mentioned soy - flavored peptide in the preparation of food or compound seasonings.

[0036] The soy - flavored peptide of this application can also be used in combination with other seasonings to prepare food or compound seasonings.

[0037] In the soy - flavored peptide of this application, the contents of target peptides and target amino acids (such as umami peptides and umami amino acids) are high. Using the above - mentioned soy - flavored peptide can enhance the freshness and the oral aftertaste time of food and compound seasonings, and improve the overall flavor.

[0038] According to experiments, a single - source enzyme cannot fully hydrolyze soy protein; without taking pH regulation measures, it greatly inhibits the release of umami substances; or the regulated pH level is not within the range of 6.0 - 6.4, weakening the umami - enhancing ability of umami peptides in the blanched sauce. Thus, it shows that applying the soy - flavored peptide prepared by the method of this application to the blanched sauce can effectively improve the taste of the blanched sauce.

[0039] Compared with the prior art, this application has the following beneficial effects:

[0040] This application provides a soy - flavored peptide, its preparation method and application. This application selects Aspergillus oryzae as a fermenting agent, and the microbial endogenous enzymes produced by its sufficient fermentation act together with the compound enzyme preparation. The rich enzyme system can effectively hydrolyze macromolecules such as proteins, providing relevant taste substances for the subsequent enzymatic hydrolysis products; in the soy - flavored peptide prepared by enzyme hydrolysis and Maillard reaction of this application, the contents of target peptides and target amino acids (such as umami peptides and umami amino acids) are high; in the application of compound condiment products with umami enhancement as the main function, the freshness score can be increased by 0.5 - 2 times. In addition, on the basis of enhancing freshness, it can also enhance the taste richness of food or compound seasonings and extend the aftertaste time. Description of the Drawings

[0041] Figure 1 It is a sensory score chart of the blanched sauce prepared from each soy - flavored peptide. Detailed Embodiments

[0042] To better illustrate the purpose, technical solution and advantages of this application, the following will further explain this application in combination with the attached drawings and specific embodiments.

[0043] In the following examples and comparative examples, unless otherwise specified, the experimental methods used are conventional methods. The materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified, and the component raw materials used in each parallel experiment are of the same kind.

[0044] The experimental methods for the test indexes involved in the embodiments of this application are as follows:

[0045] Determination of amino acid peptide nitrogen: It is determined by the automatic titration method according to GB5009.236-2016.

[0046] Determination of total nitrogen: It is determined by the semi-automatic Kjeldahl nitrogen analyzer method according to GB5009.5-2016.

[0047] Protein recovery rate (%) = (total nitrogen content of the extract ÷ total nitrogen content of the raw material) × 100%.

[0048] Determination of peptide nitrogen: Mix the enzymatic hydrolysate with 20% (w / w) trichloroacetic acid in a ratio of 1:1, let it stand for 30 min, centrifuge at 3500 r / min for 10 min, take the supernatant and filter it with medium-speed qualitative filter paper. The filtered solution is the dissolution solution of amino acids and small peptides.

[0049] Peptide nitrogen (%) = [(total nitrogen in the dissolution solution - ammonia nitrogen in the dissolution solution) ÷ total nitrogen in the enzymatic hydrolysate] × 100%.

[0050] Analysis of amino acid composition: It is analyzed according to the method of GB5009.124-2016.

[0051] Analysis of peptide molecular weight distribution: It is analyzed according to the method of GB / T22492-2008.

[0052] Sensory evaluation method for soy flavor peptides:

[0053] The quantitative descriptive analysis method is adopted, and 10 professional sensory personnel are selected to conduct sensory evaluation on the umami of soy flavor peptides. The sensory base solution is prepared by mixing table salt, white sugar, monosodium glutamate and disodium 5'-ribonucleotide in proportions of 12%, 8%, 2.5% and 0.2% respectively. The soy flavor peptide is dissolved in the sensory base solution at a ratio of 3‰ to prepare a sensory solution. The sensory personnel need to gargle before changing samples. The sensory base solution is used as a control and set as 4 points. The scoring range of the test group solution is 1 (weak) - 7 (strong) points. After the sensory evaluation, the average score of each sensory personnel is used as the final score for the umami test of soy flavor peptides.

[0054] Sensory evaluation method for blanched sauce: The quantitative descriptive analysis method was adopted, and 10 professional sensory panelists were selected to conduct sensory evaluation on the umami of the blanched sauce. The soy sauce flavor peptide was dissolved in the blanched sauce at a ratio of 2‰, and the blanched sauce sample without added soy sauce flavor peptide was used as a control, which was set as 4 points. The scoring range of the test group solution was from 1 (weak) to 7 (strong) points. After the sensory evaluation, the average score of each sensory panelist was used as the final score for the umami test of the blanched sauce.

[0055] Example 1, a soy flavor peptide and its preparation method

[0056] This embodiment provides a preparation method of soy sauce flavor peptide, including the following steps:

[0057] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.5, cook at 121°C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 28°C for 36 h to obtain a fermented material.

[0058] S2. Mix the fermented material with water at a ratio of 1:2.5, shear at 10000 r / min for 30 s to prepare a uniform slurry; then add a compound enzyme preparation (composed of 0.1% neutral protease, 0.6% trypsin, 0.1% bromelain, 0.2% glutaminase, and 0.2% aminopeptidase) to the slurry and stir evenly. Enzymatic hydrolysis is carried out at a constant temperature of 50°C. When the enzymatic hydrolysis reaches 1 h, the pH is adjusted to 6.0, and then continuous enzymatic hydrolysis is carried out for 9 h.

[0059] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 100°C for 15 min; after cooling, centrifuge at 10000 r / min for 20 min in a centrifuge to obtain an enzymatic hydrolysis supernatant.

[0060] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 55°C until the solid content is 55%, add 5% (w / w) of salt and mix evenly, and sterilize at 100°C for 1 h to obtain soy sauce flavor peptide A.

[0061] Example 2, a soy flavor peptide and its preparation method

[0062] This embodiment provides a preparation method of soy sauce flavor peptide, including the following steps:

[0063] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121°C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32°C for 40 h to obtain a fermented material.

[0064] S2. Mix the fermented material with water at a ratio of 1:3, and shear for 40 s at 11000 r / min to prepare a uniform slurry; then add a compound enzyme preparation (composed of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, 0.1% glutaminase, and 0.1% aminopeptidase) to the slurry and stir evenly. Conduct enzymatic hydrolysis at a constant temperature of 60 °C. Adjust the pH to 6.4 at 0.5 h of enzymatic hydrolysis, and then continuously conduct enzymatic hydrolysis for 11.5 h.

[0065] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95 °C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min to obtain the enzymatic hydrolysis supernatant.

[0066] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 60 °C until the solid content is 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95 °C for 2 h to obtain soy flavor peptide B.

[0067] Example 3, a soy flavor peptide and its preparation method

[0068] This example provides a method for preparing soy flavor peptide, including the following steps:

[0069] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:2, cook at 115 °C for 20 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 30 °C for 38 h to obtain the fermented material.

[0070] S2. Mix the fermented material with water at a ratio of 1:3.5, and shear for 25 s at 9000 r / min to prepare a uniform slurry; then add a compound enzyme preparation (composed of 0.1% neutral protease, 0.6% trypsin, 0.08% bromelain, 0.2% glutaminase, and 0.3% aminopeptidase) to the slurry and stir evenly. Conduct enzymatic hydrolysis at a constant temperature of 50 °C. Adjust the pH to 6.3 at 3 h of enzymatic hydrolysis, and then continuously conduct enzymatic hydrolysis for 8 h.

[0071] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 90 °C for 20 min. After cooling, centrifuge at 9000 r / min for 20 min to obtain the enzymatic hydrolysis supernatant.

[0072] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 55 °C until the solid content is 60%, add 8% (w / w) of table salt and mix evenly, and sterilize at 100 °C for 0.5 h to obtain soy flavor peptide C.

[0073] Example 4, a soy flavor peptide and its preparation method

[0074] This example provides a method for preparing soy flavor peptide, including the following steps:

[0075] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1, cook at 115°C for 20 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 26°C for 34 h to obtain the fermented material.

[0076] S2. Mix the fermented material with water at a ratio of 1:4, shear at 10000 r / min for 20 s to prepare a uniform sizing slurry; then add a complex enzyme preparation (consisting of 0.1% neutral protease, 0.3% trypsin, 0.05% bromelain, 0.1% glutaminase, and 0.4% aminopeptidase) to the sizing slurry, stir evenly. Carry out enzymatic hydrolysis at a constant temperature of 50°C, adjust the pH to 6.2 when enzymatic hydrolysis reaches 4 h, and then continuously carry out enzymatic hydrolysis for 7 h.

[0077] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 90°C for 20 min. After cooling, centrifuge at 8000 r / min for 30 min to obtain the enzymatic hydrolysis supernatant.

[0078] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 65°C to a solid content of 65%, add 4% (w / w) of table salt and mix evenly, and sterilize at 90°C for 2 h to obtain soybean flavor peptide D.

[0079] Comparative Example 1, a soy flavor peptide and its preparation method

[0080] Compared with Example 2, the difference in Comparative Example 1 is that in step S1, Aspergillus oryzae 3.042 is not inoculated, and other steps are the same as in Example 2.

[0081] This comparative example provides a method for preparing soybean flavor peptide, including the following steps:

[0082] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121°C for 15 min to obtain the cooked material.

[0083] S2. Mix the fermented material with water at a ratio of 1:3, shear at 11000 r / min for 40 s to prepare a uniform sizing slurry; then add a complex enzyme preparation (consisting of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, 0.1% glutaminase, and 0.1% aminopeptidase) to the sizing slurry, stir evenly. Carry out enzymatic hydrolysis at a constant temperature of 60°C, adjust the pH to 6.4 when enzymatic hydrolysis reaches 0.5 h, and then continuously carry out enzymatic hydrolysis for 11.5 h.

[0084] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95°C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min to obtain the enzymatic hydrolysis supernatant.

[0085] S4. Concentrate the enzymatic hydrolysate supernatant under reduced pressure at 60°C until the solid content reaches 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95°C for 2 h to obtain soy flavor peptide E.

[0086] Comparative Example 2, a soy flavor peptide and its preparation method

[0087] Compared with Example 2, the difference in Comparative Example 2 is that no complex enzyme preparation is added in step S2, and other steps are the same as those in Example 2.

[0088] This comparative example provides a method for preparing soy flavor peptide, including the following steps:

[0089] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121°C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32°C for 40 h to obtain a fermented material.

[0090] S2. Mix the fermented material with water at a ratio of 1:3, shear at 11000 r / min for 40 s to prepare a uniform slurry; keep the slurry at a constant temperature of 60°C for enzymatic hydrolysis, adjust the pH to 6.4 at 0.5 h of enzymatic hydrolysis, and then continuously hydrolyze for 11.5 h.

[0091] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95°C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min to obtain the enzymatic hydrolysate supernatant.

[0092] S4. Concentrate the enzymatic hydrolysate supernatant under reduced pressure at 60°C until the solid content reaches 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95°C for 2 h to obtain soy flavor peptide F.

[0093] Comparative Example 3, a soy flavor peptide and its preparation method

[0094] Compared with Example 2, the difference in Comparative Example 3 is that the pH is not adjusted in step S2 (the initial pH of the enzymatic hydrolysis material is 5.8), and other steps are the same as those in Example 2.

[0095] This comparative example provides a method for preparing soy flavor peptide, including the following steps:

[0096] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121°C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32°C for 40 h to obtain a fermented material.

[0097] S2. Mix the fermented material and water in a ratio of 1:3, and shear for 40 s at 11000 r / min to prepare a uniform slurry; then add a compound enzyme preparation (consisting of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, 0.1% glutaminase, and 0.1% aminopeptidase) to the slurry and stir evenly. The slurry is enzymatically hydrolyzed at a constant temperature of 60 °C for 11.5 h.

[0098] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95 °C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min in a centrifuge to obtain the enzymatic hydrolysis supernatant.

[0099] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 60 °C until the solid content is 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95 °C for 2 h to obtain soy flavor peptide G.

[0100] Comparative Example 4, a soy flavor peptide and its preparation method

[0101] Compared with Example 2, the difference in Comparative Example 4 is that the pH in step S2 is adjusted to 5.5, and the other steps are the same as those in Example 2.

[0102] This comparative example provides a method for preparing soy flavor peptide, including the following steps:

[0103] S1. Mix soybeans and / or defatted soybeans with water in a ratio of 1:1.8, cook at 121 °C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32 °C for 40 h to obtain a fermented material.

[0104] S2. Mix the fermented material and water in a ratio of 1:3, and shear for 40 s at 11000 r / min to prepare a uniform slurry; then add a compound enzyme preparation (consisting of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, 0.1% glutaminase, and 0.1% aminopeptidase) to the slurry and stir evenly. Enzymatically hydrolyze at a constant temperature of 60 °C, adjust the pH to 5.5 at 0.5 h of enzymatic hydrolysis, and then continuously enzymatically hydrolyze for 11.5 h.

[0105] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95 °C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min in a centrifuge to obtain the enzymatic hydrolysis supernatant.

[0106] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 60 °C until the solid content is 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95 °C for 2 h to obtain soy flavor peptide H.

[0107] Comparative Example 5, a soy flavor peptide and its preparation method

[0108] Compared with Example 2, the difference in Comparative Example 5 is that in step S2, the pH is adjusted to 6.8, and the other steps are the same as those in Example 2.

[0109] This comparative example provides a method for preparing soy flavor peptides, comprising the following steps:

[0110] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121 °C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32 °C for 40 h to obtain a fermented material.

[0111] S2. Mix the fermented material with water at a ratio of 1:3, shear at 11000 r / min for 40 s to prepare a uniform sizing slurry; then add a compound enzyme preparation (composed of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, 0.1% glutaminase, and 0.1% aminopeptidase) to the sizing slurry, stir evenly. Carry out enzymatic hydrolysis at a constant temperature of 60 °C, adjust the pH to 6.8 at 0.5 h of enzymatic hydrolysis, and then continuously carry out enzymatic hydrolysis for 11.5 h.

[0112] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95 °C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min to obtain an enzymatic hydrolysis supernatant.

[0113] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 60 °C to a solid content of 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95 °C for 2 h to obtain soy flavor peptide I.

[0114] Comparative Example 6, a soy flavor peptide and its preparation method

[0115] Compared with Example 2, the difference in Comparative Example 6 is that in step S2, the compound enzyme preparation is composed of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, and 0.1% aminopeptidase, and the other steps are the same as those in Example 2.

[0116] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121 °C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32 °C for 40 h to obtain a fermented material.

[0117] S2. Mix the fermented material with water at a ratio of 1:3, shear at 11000 r / min for 40 s to prepare a uniform sizing slurry; then add a compound enzyme preparation (composed of 0.08% neutral protease, 0.6% trypsin, 0.2% bromelain, and 0.1% aminopeptidase) to the sizing slurry, stir evenly. Carry out enzymatic hydrolysis at a constant temperature of 60 °C, adjust the pH to 6.4 at 0.5 h of enzymatic hydrolysis, and then continuously carry out enzymatic hydrolysis for 11.5 h.

[0118] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95°C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min in a centrifuge to obtain the enzymatic hydrolysis supernatant.

[0119] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 60°C until the solid content is 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95°C for 2 h to obtain the soy sauce flavor peptide J.

[0120] Comparative Example 7, a soy flavor peptide and its preparation method

[0121] Compared with Example 2, the difference in Comparative Example 7 is that in step S2, the complex enzyme preparation consists of 0.08% of neutral protease, 0.6% of alkaline protease, 0.2% of bromelain, 0.1% of glutaminase, and 0.1% of aminopeptidase, and other steps are the same as in Example 2.

[0122] S1. Mix soybeans and / or defatted soybeans with water at a ratio of 1:1.8, cook at 121°C for 15 min, inoculate Aspergillus oryzae 3.042 after cooling, and ferment at 32°C for 40 h to obtain the fermented material.

[0123] S2. Mix the fermented material with water at a ratio of 1:3, shear at 11000 r / min for 40 s to prepare a uniform slurry for adjustment; then add a complex enzyme preparation (consisting of 0.08% of neutral protease, 0.6% of alkaline protease, 0.2% of bromelain, 0.1% of glutaminase, and 0.1% of aminopeptidase) to the slurry for adjustment and stir evenly. Enzymatically hydrolyze at a constant temperature of 60°C, adjust the pH to 6.4 when the enzymatic hydrolysis is 0.5 h, and then continuously enzymatically hydrolyze for 11.5 h.

[0124] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 95°C for 15 min; after cooling, centrifuge at 8000 r / min for 30 min in a centrifuge to obtain the enzymatic hydrolysis supernatant.

[0125] S4. Concentrate the enzymatic hydrolysis supernatant under reduced pressure at 60°C until the solid content is 65%, add 7% (w / w) of table salt and mix evenly, and sterilize at 95°C for 2 h to obtain the soy sauce flavor peptide K.

[0126] The results of amino acid nitrogen, protein recovery rate, peptide nitrogen, umami score, and other sensory descriptions of the soy sauce flavor peptides A, B, C, D, E, F, G, H, I, J, and K prepared above are shown in Table 1.

[0127] The amino acid compositions of the soy sauce flavor peptides A, B, C, D, E, F, G, H, I, J, and K are shown in Table 2.

[0128] The results of the peptide molecular weight distribution of the soy sauce flavor peptides A, B, C, D, E, F, G, H, I, J, and K are shown in Table 3.

[0129] Table 1 Physicochemical indexes and sensory evaluation results of soy flavor peptides

[0130]

[0131] Table 2 Free amino acid composition of soy flavor peptides

[0132]

[0133]

[0134]

[0135] Table 3 Peptide molecular weight distribution of soy flavor peptides

[0136]

[0137]

[0138] Table 1 summarizes the amino acid nitrogen, protein recovery rate, peptide nitrogen and sensory evaluation results of soy flavor peptides in the examples and comparative examples. The three indexes of amino acid nitrogen, protein recovery rate and peptide nitrogen can represent the hydrolysis degree of protein in the raw materials, and at the same time provide material support for taste sense.

[0139] In Table 1, soy flavor peptides E, F, G, H, I, J, K correspond to Comparative Examples 1, 2, 3, 4, 5, 6, 7 respectively, which are no biological fermentation, no exogenous enzyme, no pH regulation, pH regulated to 5.5, pH regulated to 6.8, no glutaminase, and trypsin replaced by neutral protease. The initial pH of the enzymolysis material without pH regulation in Comparative Example 3 is 5.8, which is higher than that in Comparative Example 4 and lower than that in Comparative Example 5. The content of amino acid nitrogen in Examples 1-4 is significantly higher than that in the seven comparative examples, about 1.3-2.5 times that of the comparative examples. The amino acid nitrogen in Comparative Examples 1, 2, and 7 is at a low level, indicating that endogenous and exogenous enzymes are important factors affecting the hydrolysis degree of raw material protein. Therefore, optimizing the endogenous and exogenous enzyme processes can increase the generation of amino acid nitrogen and provide a flavor substance basis for soy flavor peptides.

[0140] The protein recovery rate was used to reflect the raw material utilization rate. The protein recovery rates of Examples 1 to 4 were 1.16 to 2.16 times those of Comparative Examples 1 to 7. Among them, the decreases in the protein recovery rates of Comparative Examples 6 and 7 were less than those of other comparative examples, indicating that the lack of addition of glutaminase and the replacement of trypsin with neutral protease would reduce the raw material utilization rate, but the influence degree was relatively low. In addition, the peptide nitrogen ratio in the examples would also increase significantly compared with the comparative examples. Among the seven comparative examples, Comparative Example 7 had the highest peptide nitrogen ratio. This was because the neutral protease had more action sites, resulting in a decrease in the degree of hydrolysis and an increase in the peptide ratio, which was consistent with the ammonia nitrogen result. The umami scores of the comparative examples were significantly lower than those of the examples, and there were defects in both the fullness and aftertaste. Especially in Comparative Example 7, the bitter taste was slightly heavier due to the neutral protease.

[0141] The above results all indicate that biological fermentation, exogenous enzymes, and pH regulation are all important means to enhance the protein hydrolysis ability. The ammonia nitrogen content, protein recovery rate, and peptide nitrogen ratio of Example 2 were all at the highest levels, and the fresh taste of the soy flavor peptides under this condition was the most prominent, very full and with a long aftertaste. Biological fermentation is a process to promote the production of enzymes by microorganisms. Aspergillus oryzae secretes a rich enzyme system during the fermentation process, especially proteases. Under the combined action of exogenous enzymes, the proteins in the soybean cake are fully hydrolyzed. The fermentation time and enzymatic hydrolysis time of Example 2 were slightly longer. Under this condition, the pH was adjusted to 6.4 to maximize the hydrolysis degree and hydrolysis ability of the enzyme system. Therefore, the method of this application can dissolve specific umami substances to the greatest extent and enhance the umami-enhancing ability of soy flavor peptides.

[0142] Table 2 shows the analysis results of free amino acids for four groups of examples and seven groups of comparative examples.

[0143] The results show that the total free amino acid content in Examples 1-4 is 1.32-2.17 times that of the seven groups of comparative examples. The total free amino acid content in Comparative Example 3 is the highest, followed by Comparative Example 1, and the total free amino acid content in Comparative Example 2 is the lowest. It is speculated that this is one of the reasons for its lowest umami score. This also indicates that the addition of exogenous enzymes has the greatest impact on the umami of soy flavor peptides, followed by biological fermentation and pH regulation processes, and finally the adjustment of exogenous enzymes. The total free amino acid and umami amino acid contents in Comparative Examples 4 and 5 are higher than those in Comparative Examples 1 and 2 and slightly lower than those in Comparative Example 3. This is because adjusting the pH to 5.5 and 6.8 is not the optimal level for promoting amino acid production. The peptide nitrogen ratios in Comparative Examples 4 and 5 are also lower than those in Comparative Example 3, which is because too high or too low pH regulation is not conducive to peptide production. Glutaminase is missing in the enzymatic hydrolysis of Comparative Example 6. The results of free amino acids show that the content of glutamic acid (umami amino acid) generated under this condition is significantly reduced, and the proportion of umami amino acids is also at the lowest level. Trypsin was replaced by neutral protease in Comparative Example 7, and the total free amino acid content was low, but the total amount and percentage of bitter amino acids were the highest. This is because neutral protease is prone to release hydrophobic amino acids such as leucine and phenylalanine, so the sensory solution is slightly bitter (Table 1). It can be seen from this that the synergistic optimization of the three processes in this application can increase the overall umami amino acids, which are the basis of umami substances, by 0.33-1.25 times, and glutamic acid is the most abundant among them.

[0144] Table 3 shows the results of the molecular weight distribution of soy flavor peptides. Umami is mainly affected by small molecules with a peptide molecular weight of less than 5000 Da. The molecular weight distribution of peptides can also reflect the hydrolysis degree of raw materials. The small peptides with a molecular weight of less than 5000 Da in the four examples of soy flavor peptides A, B, C, and D are higher than 90%, and the proportion of peptides with a molecular weight of less than 1000 Da is as high as more than 75%. However, the proportion of small peptides with a molecular weight of less than 1000 Da in Comparative Examples 1-7 is relatively low. Combining the results of Table 1 and Table 2, it shows that under the three conditions of Examples 1-4, the proteins in soybeans can be fully hydrolyzed into small peptides and amino acids, both of which contribute greatly to umami.

[0145] Figure 1 The sensory score chart of the blanched juice prepared from each soy flavor peptide. From Figure 1It can be seen that compared with Comparative Examples 1-7, the sensory scores of the blanched juice prepared in Examples 1-4 are higher than those of the blanched juice prepared in Comparative Examples 1-7. This is because in Comparative Examples 1 and 2, the enzymes from a single source cannot fully hydrolyze soy protein, and in Comparative Example 3, no pH regulation measures were taken, which greatly inhibited the release of umami substances. In addition, the pH levels regulated in Comparative Examples 4 and 5 weakened the umami-enhancing ability of the taste peptides in the blanched juice; in Comparative Example 6, the lack of participation of glutaminase reduced the production of umami amino acids; in Comparative Example 7, the high content of bitter amino acids masked the umami. Therefore, the overall taste and texture of the 7 comparative examples are not as good as those of Examples 1-4. This shows that the application of the soy taste peptides prepared by the method of the present application to the blanched juice can effectively improve the taste of the blanched juice.

[0146] In summary, in the examples of the present application, through biological fermentation first, followed by enzymatic hydrolysis with the addition of exogenous enzymes, and effective pH regulation during the enzymatic hydrolysis process, the umami-enhancing ability of the soy taste peptides is significantly strengthened, and the richness of the overall taste and the lasting aftertaste are also significantly improved.

[0147] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing a soy - flavored peptide, characterized in that, It includes the following steps: S1. Mix soybeans and / or defatted soybeans with water and steam them. After cooling, inoculate Aspergillus oryzae for fermentation to obtain a fermented material. S2. Mix the fermented material obtained in step S1 with water, perform shearing treatment to obtain a sizing slurry. Then, add a compound enzyme preparation to the sizing slurry, stir for enzymatic hydrolysis, and adjust the pH value to 6.0 - 6.4 to obtain an enzymatic hydrolysate. S3. Perform enzyme inactivation treatment on the enzymatic hydrolysate, and then centrifuge to obtain an enzymatic hydrolysis supernatant. S4. Concentrate, formulate, and sterilize the enzymatic hydrolysis supernatant to prepare soy flavor peptides. The compound enzyme preparation includes neutral protease, trypsin, bromelain, glutaminase, and aminopeptidase.

2. The preparation method of the soy flavor peptide according to claim 1, wherein, The compound enzyme preparation includes components with the following mass concentrations: Neutral protease 0.08 - 0.1%, trypsin 0.3 - 0.6%, bromelain 0.05 - 0.2%, glutaminase 0.1 - 0.2%, and aminopeptidase 0.1 - 0.4%.

3. The preparation method of the soy flavor peptide according to claim 1, characterized in that, In step S1, the mass ratio of the soybeans and / or defatted soybeans to water is 1:(1 - 2).

4. The preparation method of the soy flavor peptide according to claim 1, characterized in that, In step S1, the Aspergillus oryzae includes Aspergillus oryzae 3.

042.

5. The preparation method of the soy flavor peptide according to claim 1, characterized in that, In step S1, the fermentation temperature is 26 - 38°C, and the fermentation time is 34 - 40 h.

6. The preparation method of the soy flavor peptide according to claim 1, characterized in that, In step S2, the mass ratio of the fermented material to water is 1:(2.5 - 4); The shearing speed is 9000 - 11000 r / min, and the shearing time is 20 - 40 s.

7. The preparation method of the soy flavor peptide according to claim 1, characterized in that, In step S2, the enzymatic hydrolysis temperature is 50 - 60°C, the enzymatic hydrolysis time is 10 - 12 h, and the pH of the enzymatic hydrolysate is adjusted to 6.0 - 6.4 when enzymatic hydrolysis is carried out for 0.5 - 4 h.

8. The preparation method of the soy flavor peptide according to claim 1, characterized in that, In step S3, the enzyme inactivation temperature is 90 - 100°C, and the enzyme inactivation time is 15 - 20 min; In step S3, the centrifugation speed is 8000 - 10000 r / min, and the centrifugation time is 20 - 30 min; In step S4, the concentration includes: concentrating the enzymatic hydrolysis supernatant under negative pressure at a temperature of 55 - 65°C until the solid content is 55 - 65% to obtain a concentrate; In step S4, the formulation includes: adding table salt with a mass concentration of 0 - 8% (w / w) to the concentrate; In step S4, the sterilization temperature is 90 - 100°C, and the sterilization time is 0.5 - 2 h.

9. The soy flavor peptides prepared by the method for preparing soy flavor peptides according to any one of claims 1 - 8.

10. The application of the soy flavor peptides according to claim 9 in the preparation of foods or compound seasonings.

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