Rice peptide product, method for preparing the same, and use thereof

Abstract

The application provides a rice peptide product, a preparation method and application thereof. The preparation method comprises the following steps: S1, centrifuging a rice protein solution to obtain a rice protein supernatant and a rice protein heavy phase; S2, dissolving the rice protein heavy phase, and then sequentially performing a first enzymolysis reaction and a second enzymolysis reaction to obtain a rice protein enzymolysis solution; and S3, sequentially performing filtration, concentration and drying on the rice protein enzymolysis solution to obtain the rice peptide product. The enzyme participating in the first enzymolysis reaction is a food-grade protease and a food-grade flavor enzyme, and the enzyme participating in the second enzymolysis reaction is a food-grade glutamine enzyme. The present application does not need to use chemical reagents to pretreat raw materials containing rice protein, and can obtain a rice peptide product with good thick and fresh flavors through enzymolysis treatment by using biological enzymes, and the bitter taste existing in the rice peptide product obtained by the prior art is removed, which is beneficial to subsequent food processing and easy to be widely promoted and applied.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and more specifically, to a rice peptide product, its preparation method, and its application. Background Technology

[0002] While there are many grain processing plants, seasoning production plants, hydrolyzed starch sugar production plants, and wineries involved in the processing and utilization of rice, rice resources, especially early-ripened rice, broken rice, aged rice, and rice protein residue from hydrolyzed starch sugar production, have not been fully utilized for secondary processing, resulting in their economic value not being fully realized. Developing rice protein and rice peptides from early-ripened rice, broken rice, aged rice, and rice residue is an effective way to transform them into high-value-added products.

[0003] Rice protein is a high-quality plant-based protein. It is rich in nutrients and of better quality than wheat and corn proteins. It contains a certain amount of lysine, and its amino acid composition is close to that of a "complete protein," with a biological value (the ratio of retained nitrogen to absorbed nitrogen) as high as 77%. Furthermore, rice protein has low allergenicity and does not contain anti-nutritional factors, making it suitable for developing infant and toddler foods.

[0004] Rice peptides are small-molecule polypeptides obtained by processing large rice protein molecules through protease treatment, using rice protein as a raw material. They can be widely used in general food, nutritional food, health food, and other related fields. The main characteristics of rice peptides are: First, rice peptides are low in allergens and are not allergens. Related studies show that the antigenicity of rice peptides is only 1 / 100 to 1 / 1000 of that of rice protein, meaning that consumption will not cause allergic reactions. This property has practical clinical value, providing a relatively safe protein product for people prone to food allergies. Second, rice peptides are easily digested and absorbed. Previous studies suggested that the human body mainly absorbs protein in the form of amino acids, but modern nutritional research has found this to be different. After enzymatic breakdown in the digestive tract, ingested protein is mainly digested and absorbed in the form of oligopeptides, with a very small proportion absorbed in the form of free amino acids. Therefore, rice peptides are better absorbed in the intestines than proteins and free amino acids, and can also act as bioactive peptides to induce biological effects in the body at the metabolic level. Third, rice peptides have a well-balanced amino acid profile and are rich in nutrients. They contain 18 amino acids, especially eight essential amino acids that the human body cannot synthesize, and their composition is largely consistent with human needs, providing the body with all the necessary amino acids. In addition to the above advantages, rice peptides also have good solubility, heat and acid resistance. Furthermore, they possess various physiological functions such as easy absorption, blood pressure reduction, and antioxidant effects. They can be used as a food ingredient or additive in seasonings, instant drinks, and convenience foods.

[0005] With the continuous discovery of the functions of rice peptides, their research and development are attracting the attention of scientists worldwide. However, there are still certain equipment and technological limitations in the industrial production of rice peptides both domestically and internationally. The pretreatment process for preparing rice peptides from rice protein is relatively complex, requiring the use of chemical reagents. Furthermore, the enzymatic hydrolysis process involves numerous steps, resulting in high production and equipment costs, making it unsuitable for industrialization. Additionally, the prepared rice peptides tend to have a bitter taste and lack umami and rich flavor, limiting their application in the food industry. Therefore, further optimization and improvement are needed to promote the application of rice peptide products. Summary of the Invention

[0006] The main objective of this invention is to provide a rice peptide product, its preparation method, and its application, in order to solve the problem that rice peptide products prepared in the prior art have a certain bitter taste.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a method for preparing a rice peptide product is provided, the method comprising: S1, centrifuging a rice protein solution to obtain a rice protein clear liquid and a rice protein heavy phase; S2, dissolving the rice protein heavy phase and then sequentially performing a first enzymatic hydrolysis reaction and a second enzymatic hydrolysis reaction to obtain a rice protein hydrolysate; S3, sequentially filtering, concentrating, and drying the rice protein hydrolysate to obtain the rice peptide product; wherein the enzymes participating in the first enzymatic hydrolysis reaction are food-grade protease and food-grade flavor enzyme, and the enzyme participating in the second enzymatic hydrolysis reaction is food-grade glutaminase.

[0008] Further, the mass concentration of dry matter in the rice protein solution in S1 is 5-20%; preferably, the dry matter is selected from any of the following: coarse rice protein residue, rice protein powder, or high-purity rice protein.

[0009] Furthermore, before the first centrifugation, the preparation method also includes heating the rice protein solution to a temperature of 70-80°C; preferably, the heating time is 1-5 hours; preferably, the rotation speed of the first centrifugation is 2000-8000 rpm; preferably, the first centrifugation time is 10-30 minutes; preferably, the temperature of the first centrifugation is 50-70°C.

[0010] Further, the mass concentration of the rice protein in the rice protein heavy phase solution obtained after dissolving the rice protein heavy phase in S2 is 5-20%; preferably, the temperature of the first enzymatic hydrolysis reaction is 40-60℃; preferably, the time of the first enzymatic hydrolysis reaction is 3-20h; preferably, the pH value of the first enzymatic hydrolysis reaction is 5.0-9.0; preferably, the mass fraction of food-grade protease and food-grade flavor enzyme is independently 0.1-2.0%.

[0011] Further, the temperature of the second enzymatic hydrolysis reaction is 50-70℃; preferably, the time of the second enzymatic hydrolysis reaction is 5-20h; preferably, the pH value of the second enzymatic hydrolysis reaction is 6.0-10.0; preferably, the mass fraction of food-grade glutaminase is 0.1-2.0%.

[0012] Furthermore, after the second enzymatic hydrolysis reaction, the preparation method further includes: inactivating the enzyme in the hydrolysis product and cooling it to obtain rice protein hydrolysate; preferably, the temperature of the enzyme inactivation treatment is 80-90℃; preferably, the time of the enzyme inactivation treatment is 1-5h; preferably, the temperature after cooling is 45-65℃.

[0013] Furthermore, in step S3, before filtering the rice protein hydrolysate, the preparation method further includes: performing a second centrifugation on the rice protein hydrolysate to obtain a clear rice protein hydrolysate; preferably, the rotation speed of the second centrifugation is 2000-8000 rpm; preferably, the second centrifugation time is 10-30 min; preferably, the temperature of the second centrifugation is 45-65℃.

[0014] Further, the filtration is microfiltration; preferably, the pore size of the microfiltration membrane is 0.05-1 μm; preferably, the filtration temperature is 45-70℃; preferably, the filtration time is 2-3 h; preferably, the concentration temperature is 45-55℃; preferably, the mass concentration of dry matter in the concentrate is 30-50%; preferably, the drying includes spray drying; preferably, the outlet air temperature of the spray drying is 70-100℃; preferably, the inlet air temperature of the spray drying is 150-220℃.

[0015] To achieve the above objectives, according to a second aspect of the present invention, a rice peptide product obtained by the above preparation method is provided, wherein the peptide content of the rice peptide product with a molecular weight of 180-2000 is ≥73%; preferably, on a dry matter basis, excluding NaCl, the total nitrogen content of the rice peptide product is ≥10.0%, the amino acid nitrogen content is ≥1.87%, and the total ash content is ≤3.9%; preferably, the sodium chloride content of the rice peptide product is ≤0.52%.

[0016] To achieve the above objectives, according to a third aspect of the present invention, an application is provided for the rice peptide product obtained by the above preparation method in the preparation of condiments, instant beverages or convenience foods.

[0017] By applying the technical solution of this invention, there is no need to pre-treat the raw materials containing rice protein with chemical reagents. This application utilizes biological enzymes to obtain rice peptide products with higher content of nutrients, especially peptides with a molecular weight of 180-2000, through enzymatic hydrolysis under relatively mild conditions. This further enhances the richness and umami flavor while removing the bitterness present in rice peptide products obtained by existing technologies. This is beneficial for subsequent food processing and is easy to promote and apply widely. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0019] As mentioned in the background section, rice peptides have high nutritional value and are easily absorbed by the human body, making them a promising nutritional source for food processing. However, current domestic and international standards for the industrial production of rice peptides face certain limitations related to equipment and technology. The pretreatment process for preparing rice peptides from rice protein is complex, requiring the use of chemical reagents. Furthermore, the production and equipment costs are high, making it unsuitable for industrialization. Additionally, the resulting rice peptides often have a bitter taste and lack umami or rich flavor, limiting their application in food-related fields. Therefore, this application aims to provide a new method for preparing rice peptides to further promote and improve the application of rice peptide products.

[0020] In a first typical embodiment of this application, a method for preparing a rice peptide product is provided. The method includes: S1, centrifuging a rice protein solution to obtain a rice protein clear liquid and a rice protein heavy phase; S2, dissolving the rice protein heavy phase and then sequentially performing a first enzymatic hydrolysis reaction and a second enzymatic hydrolysis reaction to obtain a rice protein hydrolysate; S3, sequentially filtering, concentrating, and drying the rice protein hydrolysate to obtain the rice peptide product; wherein the enzymes participating in the first enzymatic hydrolysis reaction are food-grade protease and food-grade flavor enzyme, and the enzyme participating in the second enzymatic hydrolysis reaction is food-grade glutaminase.

[0021] The technical solution of this application eliminates the need for pretreatment of raw materials containing rice protein using chemical reagents. By enzymatically hydrolyzing the raw materials with biological enzymes, the resulting rice peptide product contains a high content of 180-2000 peptides, is free of bitterness, possesses a certain umami flavor, and has a good taste. Specifically, proteases and flavor enzymes can break down proteins into amino acids and small peptides. Furthermore, the enzymatic hydrolysis by flavor enzymes can alter the taste and flavor of the protein. Glutaminase can further decompose the protein to produce glutamic acid, enhancing the umami flavor of the food. The combined use of these three enzymes results in a product with a richer taste and further enhanced umami flavor.

[0022] In order to further prepare rice peptide products with better nutritional content, it is necessary to select suitable raw materials containing rice protein for preparation. In a preferred embodiment, the mass concentration of dry matter in the rice protein solution in S1 is 5-20%. Preferably, the dry matter is selected from any of the following: coarse rice protein residue, rice protein powder or high-purity rice protein.

[0023] To ensure a more complete enzymatic hydrolysis reaction, the raw materials containing rice protein need to be pretreated to initially break down the protein in the raw materials. In a preferred embodiment, before the first centrifugation, the preparation method further includes heating the rice protein solution to a temperature of 70-80°C; preferably, the heating time is 1-5 hours; preferably, the first centrifugation speed is 2000 rpm-8000 rpm; preferably, the first centrifugation time is 10-30 minutes; preferably, the first centrifugation temperature is 50-70°C.

[0024] To further efficiently decompose the protein in rice protein raw materials and improve the nutritional value and flavor of the enzymatic hydrolysis products, in a preferred embodiment, the mass concentration of the rice protein heavy phase in the rice protein heavy phase solution obtained after dissolving the rice protein heavy phase in S2 is 5-20%; preferably, the temperature of the first enzymatic hydrolysis reaction is 40-60℃; preferably, the time of the first enzymatic hydrolysis reaction is 3-20h; preferably, the pH value of the first enzymatic hydrolysis reaction is 5.0-9.0; preferably, the mass fraction of food-grade protease and food-grade flavor enzyme is independently 0.1-2.0%.

[0025] To further enhance the freshness of the product obtained from the first enzymatic hydrolysis reaction more efficiently, in a preferred embodiment, the temperature of the second enzymatic hydrolysis reaction is 50-70°C; preferably, the time of the second enzymatic hydrolysis reaction is 5-20 h; preferably, the pH value of the second enzymatic hydrolysis reaction is 6.0-10.0; preferably, the mass fraction of food-grade glutaminase is 0.1-2.0%.

[0026] In order to terminate the enzymatic hydrolysis reaction in a timely manner and avoid the generation of unwanted side reactions in the later stages of the reaction with poor activity, in a preferred embodiment, after the second enzymatic hydrolysis reaction, the preparation method further includes: inactivating the enzyme in the hydrolysis product and cooling it to obtain rice protein hydrolysate; preferably, the temperature of the enzyme inactivation treatment is 80-90℃; preferably, the time of the enzyme inactivation treatment is 1-5h; preferably, the temperature after cooling is 45-65℃.

[0027] The post-processing of purifying and separating the obtained enzymatic hydrolysate can yield a product with higher purity, which can better play its role in subsequent applications. In a preferred embodiment, in S3, before filtering the rice protein hydrolysate, the preparation method further includes: performing a second centrifugation on the rice protein hydrolysate to obtain a clear rice protein hydrolysate; preferably, the rotation speed of the second centrifugation is 2000-8000 rpm; preferably, the time of the first centrifugation is 10-30 min; preferably, the temperature of the second centrifugation is 45-65℃.

[0028] To facilitate subsequent storage and application, the rice peptide product can be further concentrated and dried into powder. In a preferred embodiment, filtration is performed using a microfiltration membrane; preferably, the pore size of the microfiltration membrane is 0.05-1 μm; preferably, the filtration temperature is 45-70°C; preferably, the filtration time is 2-3 hours; preferably, the concentration temperature is 45-55°C; preferably, the mass concentration of dry matter in the concentrate is 30-50%; preferably, drying includes spray drying; preferably, the outlet air temperature of the spray dryer is 70-100°C; preferably, the inlet air temperature of the spray dryer is 150-220°C.

[0029] In a second typical embodiment of this application, a rice peptide product obtained by the above preparation method is provided, wherein the peptide content of the rice peptide product with a molecular weight of 180-2000 is ≥73%; preferably, on a dry matter basis, excluding NaCl, the total nitrogen content of the rice peptide product is ≥10.0%, the amino acid nitrogen content is ≥1.87%, and the total ash content is ≤3.9%; preferably, the sodium chloride content of the rice peptide product is ≤0.52%.

[0030] The parameters mentioned above objectively represent various properties of the product. Total nitrogen indicates the protein content, while the content of peptides with a molecular weight of 180-2000 indicates the degree of richness of flavor. Amino acid nitrogen indirectly reflects the total free amino acid content. As for ash and salt, they indicate that no acid or alkali was added during the product manufacturing process for hydrolysis, because overly vigorous hydrolysis reactions with acids and alkalis can produce carcinogens such as 3-chloropropanol and also result in a bitter taste.

[0031] In a third typical embodiment of this application, an application is provided for the rice peptide product obtained by the above preparation method in the preparation of condiments, instant beverages or convenience foods.

[0032] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0033] The food-grade protease, food-grade flavor enzyme, and food-grade glutaminase used in this application embodiment are all from Angel Enzyme Preparations (Yichang) Co., Ltd., with the food-grade protease model being EF108; the food-grade glutaminase model being Glu100; and the food-grade flavor enzyme model being FF106. The coarse rice protein residue is from Angel Yeast (Yichang) Co., Ltd.; and the rice protein powder and high-purity rice protein are from Jiangxi Hengding Food Co., Ltd.

[0034] Example 1

[0035] S1. Weigh 1000g (dry weight) of coarse rice protein residue and mix it with deionized water in an enzymatic hydrolysis tank to prepare a solution of 8333g, thus obtaining a rice protein solution with a dry matter mass fraction of 12.0%.

[0036] A rice protein solution with a mass fraction of 12.0% was heated to 78°C and heated for 3 hours. Then, it was centrifuged for the first time using a separator. The separator speed was 3500 rpm / min, the centrifugation time was 20 min, and the temperature was 60°C during the first centrifugation to obtain rice protein clear liquid and rice protein heavy phase.

[0037] S2, 800g (dry weight) of the rice protein heavy phase obtained in S1 is mixed with deionized water in an enzymatic hydrolysis tank to prepare a solution of 5714.2g, resulting in a rice protein heavy phase solution with a mass fraction of 14.0% for the rice protein heavy phase.

[0038] To carry out the first enzymatic hydrolysis reaction, the temperature inside the enzymatic hydrolysis tank was raised to 55℃, the pH value was adjusted to 6.5, and 1% food-grade protease and 0.5% food-grade flavor enzyme dissolved in deionized water at 40℃ were added respectively. The first enzymatic hydrolysis reaction time was 5 hours.

[0039] After the first enzymatic hydrolysis reaction is completed, the second enzymatic hydrolysis reaction is carried out. The pH in the enzymatic hydrolysis tank is adjusted to 6.0, the temperature is raised to 60℃, and 1% food-grade glutaminase dissolved in deionized water at 40℃ is added. The second enzymatic hydrolysis reaction takes 15 hours.

[0040] After the second enzymatic hydrolysis reaction, rice protein hydrolysate was obtained. Enzyme inactivation treatment was performed by heating to 90℃ and maintaining the temperature for 2 hours, followed by cooling to 60℃ for a second centrifugation. The second centrifugation was carried out using a separator with a speed of 4000 rpm / min and a centrifugation time of 20 minutes. The temperature during the second centrifugation was 60℃, resulting in a clear rice protein hydrolysate.

[0041] S3, the rice protein hydrolysate is fed into a 0.05μm microfiltration membrane separation system. The temperature during microfiltration is 50℃, and the membrane separation time is 2h. The light phase after microfiltration is taken into a concentrator and evaporated at 45℃ until the mass concentration of dry matter is 45%, to obtain a rice peptide paste semi-finished product. The 45% rice peptide paste semi-finished product is directly fed into a spray drying system for powder spraying. During the drying process, the inlet air temperature is 165℃, and the outlet air temperature is controlled at 85℃ to obtain the rice peptide product.

[0042] Example 2

[0043] S1. Weigh 1000g (dry weight) of crude rice protein powder and mix it with deionized water in an enzymatic hydrolysis tank to prepare a 20000g solution, thus obtaining a rice protein liquid solution with a dry matter mass fraction of 5.0%.

[0044] A rice protein solution with a mass fraction of 5.0% was heated to 70°C and heated for 5 hours. Then, it was centrifuged for the first time using a separator. The separator speed was 8000 rpm / min, the centrifugation time was 10 minutes, and the temperature was 50°C during the first centrifugation to obtain rice protein clear liquid and rice protein heavy phase.

[0045] S2, 800g (dry weight) of the rice protein heavy phase obtained in S1 is mixed with deionized water in an enzymatic hydrolysis tank to prepare a solution of 16000g, resulting in a rice protein heavy phase solution with a mass fraction of 5.0% for the rice protein heavy phase.

[0046] To carry out the first enzymatic hydrolysis reaction, the temperature inside the enzymatic hydrolysis tank was raised to 40℃, the pH value was adjusted to 5.0, and 0.1% of food-grade protease and 0.1% of food-grade flavor enzyme dissolved in deionized water at 40℃ were added respectively. The first enzymatic hydrolysis reaction time was 20h.

[0047] After the first enzymatic hydrolysis reaction is completed, the second enzymatic hydrolysis reaction is carried out. The pH in the enzymatic hydrolysis tank is adjusted to 6.5, the temperature is raised to 50°C, and 0.1% food-grade glutaminase dissolved in deionized water at 40°C is added. The second enzymatic hydrolysis reaction takes 20 hours.

[0048] After the second enzymatic hydrolysis reaction, rice protein hydrolysate was obtained. Enzyme inactivation treatment was performed by heating to 80℃ and maintaining the temperature for 5 hours, followed by cooling to 65℃ for a second centrifugation. The second centrifugation was carried out using a separator with a speed of 8000 rpm / min and a centrifugation time of 10 minutes. The temperature during the second centrifugation was 65℃, resulting in clear rice protein hydrolysate.

[0049] S3, the rice protein hydrolysate is fed into a 1.00μm microfiltration membrane separation system. The temperature during microfiltration is 45℃, and the membrane separation time is 2.5h. The light phase after microfiltration is taken into a concentrator and evaporated at 55℃ until the dry matter concentration is 30%, to obtain a rice peptide paste semi-finished product. 30% of the rice peptide paste semi-finished product is directly fed into a spray drying system for powder spraying. During the drying process, the inlet air temperature is 150℃, and the outlet air temperature is controlled at 70℃ to obtain the rice peptide product.

[0050] Example 3

[0051] S1. Weigh 1000g (dry weight) of high-purity rice protein and mix it with deionized water in an enzymatic hydrolysis tank to prepare a 5000g solution, thus obtaining a rice protein liquid solution with a dry matter mass fraction of 20.0%.

[0052] A rice protein solution with a mass fraction of 20.0% was heated to 80℃ and heated for 1 hour. Then, it was centrifuged for the first time using a separator. The separator speed was 2000 rpm / min, the centrifugation time was 30 min, and the temperature was 70℃ during the first centrifugation to obtain rice protein clear liquid and rice protein heavy phase.

[0053] S2, 800g (dry weight) of the rice protein heavy phase obtained in S1 is mixed with deionized water in an enzymatic hydrolysis tank to prepare a 4000g solution, resulting in a rice protein heavy phase solution with a mass fraction of 20.0% for the rice protein heavy phase.

[0054] To carry out the first enzymatic hydrolysis reaction, the temperature inside the enzymatic hydrolysis tank was raised to 60℃, the pH value was adjusted to 9.0, and 2% of food-grade protease and 2% of food-grade flavor enzyme dissolved in deionized water at 40℃ were added respectively. The first enzymatic hydrolysis reaction time was 3 hours.

[0055] After the first enzymatic hydrolysis reaction is completed, the second enzymatic hydrolysis reaction is carried out. The pH in the enzymatic hydrolysis tank is adjusted to 10.0, the temperature is raised to 70°C, and 2% food-grade glutaminase dissolved in deionized water at 40°C is added. The second enzymatic hydrolysis reaction takes 5 hours.

[0056] After the second enzymatic hydrolysis reaction, rice protein hydrolysate was obtained. Enzyme inactivation treatment was performed by heating to 85℃ and maintaining the temperature for 1 hour, followed by cooling to 45℃ for a second centrifugation. The second centrifugation was carried out using a separator with a speed of 2000 rpm / min and a centrifugation time of 30 minutes. The temperature during the second centrifugation was 45℃, resulting in clear rice protein hydrolysate.

[0057] S3, the rice protein hydrolysate is fed into a 0.05μm microfiltration membrane separation system. The temperature during microfiltration is 70℃, and the membrane separation time is 3h. The light phase after microfiltration is taken into a concentrator and evaporated at 50℃ until the mass concentration of dry matter is 50%, to obtain a rice peptide paste semi-finished product. 50% of the rice peptide paste semi-finished product is directly fed into a spray drying system for powder spraying. During the drying process, the inlet air temperature is 220℃, and the outlet air temperature is controlled at 100℃ to obtain the rice peptide product.

[0058] The inventors used the same operations as in Example 1. Except for the operating conditions and parameters mentioned in Table 1, all other operations and parameters were the same as in Example 1, and the rice peptide products of Examples 4-7 were obtained. The quality of the products obtained in each example was then tested and evaluated.

[0059] Table 1. Operating parameters of Examples 4-7 and Comparative Examples 1-2

[0060]

[0061] Testing experiments on the quality of rice peptide products

[0062] Total nitrogen detection method: The detection shall be carried out in accordance with the industry standard GB5009.5-2016 Method I / specify the specific detection steps.

[0063] The detection method for amino acid nitrogen is as follows: The detection shall be carried out in accordance with the industry standard GB5009.235-2016 Method I, and the specific detection steps shall be specified.

[0064] Detection method for peptide content with molecular weight of 180-2000: Detection shall be carried out in accordance with the industry standard Q / YB.J19.004 / specify the specific detection steps.

[0065] Sodium chloride detection method: The detection shall be carried out in accordance with the industry standard GB5009.44-2016 potentiometric titration method / specify the specific detection steps.

[0066] Total ash content testing method: Test according to the industry standard GB5009.4 / specify the specific testing steps.

[0067] The quality of the rice peptide products obtained in Examples 1-7 and Comparative Examples 1-2 was tested using the above method. The specific test results are shown in Table 2.

[0068] Table 2. Detection results of Examples 1-7 and Comparative Examples 1-2

[0069]

[0070] Methods for testing richness, umami, and fullness of flavor:

[0071] Weigh 2 g (±0.05 g) of the rice peptide products obtained in Examples 1-7 and Comparative Examples 1-2 into a clean glass beaker. Measure 100 mL (±1 mL) of boiled purified drinking water (80 ℃~95 ℃) into the beaker using a graduated cylinder, stir evenly with a glass rod, and let stand for 1-2 minutes. After the temperature of the solution in the beaker drops to 45-50 ℃, pour 3-5 mL of 2% rice peptide solution into a small transparent sensory cup for tasting. After each sensory evaluation, rinse your mouth 3 times with room temperature purified water, repeat the previous sensory operation, and then perform sensory evaluation on the next 2% rice peptide solution sample.

[0072] This sensory evaluation involved 5 R&D personnel from the research institute and 5 personnel from the sensory testing laboratory, totaling 10 people. The standards for each sensory evaluation are shown in Table 3, and these standards are specified in Angel Yeast's internal document number Q / YB.J19.062-2023. The testing personnel evaluated and scored the different rice peptide products on their richness, umami, and fullness of flavor. The specific test results are shown in Table 4 below.

[0073] Table 3 Evaluation criteria for richness, umami, and fullness of flavor.

[0074]

[0075] Table 4. Evaluation results of richness, umami, and fullness of flavor in Examples 1-7 and Comparative Examples 1-2

[0076]

[0077] As can be seen from the above description, the above embodiments of the present invention achieve the following technical effects: This application uses raw materials containing rice protein for enzymatic hydrolysis, followed by centrifugation, membrane separation, concentration, and spray drying processes to obtain rice peptide products with a peptide content of ≥73% and a molecular weight of 180-2000. These products can be widely used in the food industry. At the same time, the rice peptide products obtained by the preparation method of this application have no bitter taste, a certain umami taste, and a good rich flavor and full mouthfeel. They also have good application significance as seasonings. Furthermore, the amino acid composition of the rice peptide products is close to the amino acids required by the human body, and they have excellent solubility and heat resistance. In addition, the peptide content is high, which makes them easily absorbed by the human body.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a rice peptide product, characterized in that, The preparation method includes: S1, the rice protein solution is centrifuged for the first time to obtain rice protein clear liquid and rice protein heavy phase; S2, after dissolving the rice protein heavy phase, the first enzymatic hydrolysis reaction and the second enzymatic hydrolysis reaction are carried out in sequence to obtain rice protein hydrolysate; S3, the rice protein hydrolysate is sequentially filtered, concentrated and dried to obtain the rice peptide product; The enzymes involved in the first enzymatic hydrolysis reaction are food-grade protease and food-grade flavor enzyme, and the enzyme involved in the second enzymatic hydrolysis reaction is food-grade glutaminase. Wherein, the dry matter concentration in the rice protein solution in S1 is 5-20%; Prior to the first centrifugation, the preparation method further includes heating the rice protein solution at a temperature of 70-80°C for 1-5 hours. The temperature of the first enzymatic hydrolysis reaction is 40-60℃; the time of the first enzymatic hydrolysis reaction is 3-20h; and the pH value of the first enzymatic hydrolysis reaction is 5.0-9.

0. The temperature of the second enzymatic hydrolysis reaction is 50-70℃; the time of the second enzymatic hydrolysis reaction is 5-20h; and the pH value of the second enzymatic hydrolysis reaction is 6.0-10.

0. The food-grade glutaminase has a mass fraction of 0.1-2.0%; The mass fraction of the food-grade protease and the food-grade flavor enzyme are each independently 0.1-2.0%.

2. The preparation method according to claim 1, characterized in that, The dry matter is selected from any of the following: coarse rice protein residue, rice protein powder, or high-purity rice protein.

3. The preparation method according to claim 1, characterized in that, The first centrifuge operates at a speed of 2000 rpm to 8000 rpm.

4. The preparation method according to claim 1, characterized in that, The first centrifugation time is 10-30 min.

5. The preparation method according to claim 1, characterized in that, The temperature of the first centrifuge is 50-70℃.

6. The preparation method according to claim 1, characterized in that, After the second enzymatic hydrolysis reaction, the preparation method further includes: inactivating the enzyme in the hydrolysis product and cooling it to obtain the rice protein hydrolysate.

7. The preparation method according to claim 6, characterized in that, The enzyme inactivation treatment is performed at a temperature of 80-90℃.

8. The preparation method according to claim 6, characterized in that, The enzyme inactivation treatment time is 1-5 hours.

9. The preparation method according to claim 6, characterized in that, The temperature after cooling is 45-65℃.

10. The preparation method according to claim 1, characterized in that, In step S3, before filtering the rice protein hydrolysate, the preparation method further includes: performing a second centrifugation on the rice protein hydrolysate to obtain a clear rice protein hydrolysate.

11. The preparation method according to claim 10, characterized in that, The second centrifuge operates at a speed of 2000-8000 rpm.

12. The preparation method according to claim 10, characterized in that, The second centrifugation time is 10-30 min.

13. The preparation method according to claim 10, characterized in that, The temperature of the second centrifugation is 45-65℃.

14. The preparation method according to claim 1, characterized in that, The filtration is microfiltration membrane filtration.

15. The preparation method according to claim 14, characterized in that, The pore size of the microfiltration membrane is 0.05-1 μm.

16. The preparation method according to claim 14, characterized in that, The filtration temperature is 45-70℃.

17. The preparation method according to claim 14, characterized in that, The filtration time is 2-3 hours.

18. The preparation method according to claim 14, characterized in that, The concentration temperature is 45-55℃.

19. According to the preparation method of claim 14, the mass concentration of dry matter in the concentrate is 30-50%.

20. The preparation method according to claim 14, characterized in that, The drying includes spray drying.

21. The preparation method according to claim 20, characterized in that, The outlet air temperature of the spray dryer is 70-100℃.

22. The preparation method according to claim 20, characterized in that, The inlet air temperature for the spray dryer is 150-220℃.

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