Preparation method of whole rice bran beverage

Abstract

The invention discloses a preparation method of a whole rice bran beverage, which comprises the following steps: removing impurities from defatted rice bran, crushing and sieving to obtain rice bran powder with the particle size of more than 300 meshes; the preparation method comprises the following steps: mixing rice bran powder with water, and carrying out enzymolysis treatment by using phytase and alkaline protease in sequence to obtain enzymatic hydrolysate; centrifuging the obtained enzymatic hydrolysate to obtain a supernatant and a precipitate, the supernatant being a rice bran peptide extracting solution; grinding the obtained precipitate to obtain the micro-nano rice bran dietary fiber; the preparation method comprises the following steps: mixing 100 parts by weight of rice bran peptide extracting solution, 2-8 parts by weight of micro-nano rice bran dietary fiber and 5-10 parts by weight of rice bran oil, performing high-speed dispersion, and performing high-pressure homogenization to form the Pickering emulsion. Compared with the prior art, oil, protein and dietary fiber in the rice bran are utilized, the rice bran oil is stabilized in the form of Pickering emulsion under the micro-nano scale, active ingredients such as lipid, polypeptide and dietary fiber in the rice bran are utilized to the maximum extent, and the physical stability of the rice bran beverage is improved.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a preparation method of a whole rice bran beverage. Background Art

[0002] Rice bran is the main byproduct in rice processing, generally including pericarp, aleurone layer, subaleurone layer, part of germ and a small part of endosperm, accounting for 12-20wt% of rice. At present, only about 10% of rice bran is used to extract rice bran oil in my country, and the defatted rice bran after oil extraction and the remaining 90% of rice bran are not effectively utilized.

[0003] Cereal beverages are a type of cereal beverage that can be used as a meal replacement. The raw materials include brown rice, barley, highland barley, buckwheat, oats, quinoa, millet, mung beans, etc. The accelerated pace of modern life has led to students and office workers paying little attention to breakfast, which can cause some chronic diseases. While providing the human body with sufficient nutrition and energy, cereal beverages are beneficial to reducing the incidence of diabetes and chronic cardiovascular and cerebrovascular diseases. Rice bran, as the most nutritious part of rice, contains about 64% of the nutrients and functional components of rice. The nutrients and active ingredients in rice bran are mainly protein, fat and dietary fiber. The active peptides obtained by the degradation of rice bran protein have been reported to have physiological activities such as antioxidant, blood pressure lowering, anti-cancer, and cholesterol lowering. In addition, rice bran contains more than 100 antioxidants, the most effective of which are fat-soluble tocopherols, tocotrienols and γ-oryzanol. These ingredients help relieve stress, promote sleep, regulate blood sugar, etc. Therefore, rice bran is a high-quality raw material for the production of cereal beverages.

[0004] However, poor taste and stability are important reasons that restrict the production of cereal beverages. The composition of rice bran is slightly different due to the influence of rice variety, region and processing precision, and contains about 5%-7% phytic acid, 11%-15% crude protein, 25%-40% dietary fiber, and 12%-22% fat. A large amount of insoluble dietary fiber causes the rice bran to have a rough taste and a bad taste; at the same time, due to the high content of fat, protein and dietary fiber, stratification and precipitation are easy to occur during the processing and shelf life. Although the existing technology is able to process and utilize some nutrients in rice bran, due to the existence of key technical bottlenecks, there is still a lack of products that effectively utilize the full nutritional components of rice bran. Therefore, how to improve the problems of rough taste and poor stability in existing rice bran beverages and improve the utilization rate of rice bran has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the present invention is committed to providing a method for preparing a whole rice bran beverage, aiming to improve the taste, texture and stability of the rice bran beverage by optimizing the process and technical means, thereby realizing the full nutritional utilization of rice bran resources. The present invention makes full use of rice bran, adopts an enzymatic hydrolysis process to prepare rice bran active peptides; uses a ball mill to prepare micro-nano bran dietary fiber, improves the taste and acts as a natural Pickering emulsifier to stabilize rice bran oil; finally, the above-mentioned rice bran peptides, micro-nano bran dietary fiber and rice bran oil are used together for the preparation of rice bran beverages, realizing zero waste utilization of rice bran.

[0006] To achieve the above object, the present invention provides a method for preparing a whole rice bran beverage, comprising the following steps:

[0007] (1) coarse grinding: removing impurities from defatted rice bran, crushing and sieving to obtain rice bran powder with a mesh size of more than 300;

[0008] (2) enzyme treatment: the rice bran powder obtained in step (1) is mixed with water, and enzymatically treated with phytase and alkaline protease to obtain an enzymatic solution;

[0009] (3) Centrifugation: centrifuging the enzymatic hydrolyzate obtained in step (2) to obtain a supernatant and a precipitate, wherein the supernatant is the rice bran peptide extract; the centrifugation conditions are: 2000-4000g, and the centrifugation time is 5-20 minutes;

[0010] (4) fine grinding: grinding the precipitate obtained in step (3) to obtain micro-nano bran dietary fiber;

[0011] (5) Blending and homogenizing: Blending and homogenizing are performed in one of the following two ways to obtain a whole rice bran beverage:

[0012] (a) 100 parts by weight of a rice bran peptide extract, 2-8 parts by weight of micro-nano bran dietary fiber and 5-10 parts by weight of rice bran oil are mixed and dispersed at high speed, and then homogenized under high pressure to form a Pickering emulsion;

[0013] (b) 2-8 parts by weight of micro-nano bran dietary fiber and the same part by weight of rice bran peptide extract are mixed and ground for 5-10 minutes, and then the mixture is mixed with 92-98 parts by weight of additional rice bran titanium extract and 5-10 parts by weight of rice bran oil, and then dispersed at high speed, and then homogenized under high pressure to form a Pickering emulsion; wherein the total amount of rice bran titanium extract added is 100 parts by weight.

[0014] The Pickering emulsion is a whole rice bran beverage.

[0015] Furthermore, the high-speed dispersion conditions in step (5) are a rotation speed of 10000-15000 rpm and a time of 1-4 minutes.

[0016] Furthermore, the homogenization conditions in step (5) are a homogenization pressure of 30-60 MPa and a homogenization time of 5-12 minutes.

[0017] Furthermore, in step (2), the liquid ratio of rice bran to water is 1 part by weight of rice bran: 5-20 parts by weight of water.

[0018] Furthermore, the amount of phytase used in step (2) is 1-10 parts by weight of phytase per 1000 parts by weight of rice bran; the phytase treatment conditions are pH 4-7, the treatment temperature is 45-65° C., the treatment time is 0.5-4 hours, the enzyme inactivation temperature is 90-100° C., and the enzyme inactivation time is 5-15 minutes;

[0019] The protease in step (2) is one or a mixture of neutral protease, papain, alkaline protease and trypsin, and the amount of the protease is 2-20 parts by weight of protease for 1000 parts by weight of rice bran; the protease treatment conditions in step (2) are pH 5-9, the treatment temperature is 40-60°C, the treatment time is 0.5-3 hours, the enzyme inactivation temperature is 90-100°C, and the enzyme inactivation time is 5-15 minutes.

[0020] Furthermore, the reagent used for pH adjustment in step (2) is 1M sodium hydroxide solution and / or 1M hydrochloric acid.

[0021] Preferably, the particle size of the micro-nano bran dietary fiber is 50-15 μm.

[0022] Furthermore, the grinding equipment in step (4) is a planetary ball mill, the rotation speed of the ball mill is 200-500rpm, the grinding time is 15-90 minutes, and the diameter and number of agate grinding balls in the ball mill are 40 of 5mm and 16 of 10mm respectively.

[0023] Furthermore, the sieve used in step (1) is 5-300 mesh.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Enzymatic hydrolysis was used to remove phytic acid, the main anti-nutritional factor in rice bran, which was beneficial to nutrient absorption; and rice bran protein was hydrolyzed to prepare rice bran peptides, which greatly improved the antioxidant activity of rice bran beverages, significantly increased the ABTS free radical scavenging rate, and slightly increased the DPPH scavenging rate;

[0026] (2) The dietary fiber in rice bran is separated and crushed to micro-nano level using a ball mill, which avoids the roughness of large particles and improves palatability. The taste and texture are improved while retaining the beneficial dietary fiber;

[0027] (3) Dietary fiber at the micro-nano scale has good stability at the oil-water interface. Rice bran oil can be stabilized in the form of a Pickering emulsion by homogenization, which maximizes the use of dietary fiber and improves the physical stability of rice bran beverages. There will be no stratification even if it is placed at room temperature for 30 days.

[0028] (4) The present invention realizes the complete utilization of rice bran, and there is no waste in the production process. It is a green production method and also a good supplement to the rice production line for digesting rice byproducts.

[0029] (5) The raw materials and auxiliary materials used in the present invention are all from natural organic foods and are healthier. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the particle size distribution and average particle size D[3,2] of a preferred embodiment of the present invention and the comparative example.

[0031] Figure 2 The following are photos of a preferred embodiment of the present invention and a comparative example after storage at 25° C. for 7 days and 30 days.

[0032] Figure 3 It is the ABTS and DPPH free radical scavenging rate of a preferred embodiment of the present invention and a comparative example. DETAILED DESCRIPTION

[0033] A preferred embodiment and comparative examples of the present invention are described below with reference to the accompanying drawings in the specification, so that the technical content is clearer and easier to understand, and the advantages of the present invention are highlighted. This example is only a clearer explanation of the present invention, but not a limitation of the present invention. The present invention can be embodied by many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0034] Example

[0035] The whole rice bran beverage was prepared by the following steps:

[0036] (1) coarse grinding: remove impurities from defatted rice bran, put it into a colloid mill and grind it continuously for 3 minutes, and pass it through a 50-mesh sieve to obtain rice bran powder;

[0037] (2) Enzyme treatment: The rice bran powder obtained in step (1) is mixed with distilled water, with a solid-liquid ratio of 1 part rice bran to 15 parts distilled water. The pH is adjusted to 7.0 with 1M sodium hydroxide, 5 parts of phytase are added per 1000 parts of rice bran, and the mixture is heated in a water bath at 50°C for 2 hours, and then heated at 95°C for 10 minutes to inactivate the enzyme. The pH is then adjusted to 7.5 with 1M sodium hydroxide, 5 parts of alkaline protease are added per 1000 parts of rice bran, and the mixture is heated in a water bath at 50°C for 1 hour, and then heated at 95°C for 10 minutes to inactivate the enzyme.

[0038] (3) Centrifugation: Centrifuge the enzymatic hydrolyzate obtained in step (2) at 3000 x g for 15 min to obtain a supernatant and a precipitate, wherein the supernatant is the rice bran peptide extract;

[0039] (4) fine grinding: adding the precipitate obtained in step (3) into a ball mill, adding 40 5 mm agate grinding balls and 16 10 mm agate grinding balls, grinding at 300 rpm for 60 min to obtain micro-nano bran dietary fiber of 50-15 μm;

[0040] (5) Preparation: 100 parts of the rice bran peptide extract obtained after filtration in step (3), 8 parts of the micro-nano bran dietary fiber obtained in step (4), and 7 parts of rice bran oil are mixed and dispersed in a high-speed disperser at 12000 rpm for 2 minutes;

[0041] (6) Homogenization: The mixture in step (5) was homogenized at 50 MPa for 10 min.

[0042] Comparative Example

[0043] The rice bran beverage was prepared by the following method:

[0044] (1) Coarse grinding: The stabilised rice bran is cleaned of impurities, put into a grinder and continuously ground for 3 min, and passed through a 50-mesh sieve to obtain rice bran powder;

[0045] The stabilization treatment is specifically an extrusion stabilization treatment, the extrusion temperature is 125-135° C., and the screw speed is 300 r / min.

[0046] (2) mixing: the rice bran powder obtained in step (1) is mixed with 1 part of rice bran and 15 parts of distilled water according to a material-liquid ratio, and mixed evenly;

[0047] (3) Colloid mill: Add the mixed material obtained in step (2) into the colloid mill and grind it in the colloid mill for 15 minutes;

[0048] (4) Filtration: Pass the rubber slurry obtained in step (3) through a 300-mesh sieve to remove large particles;

[0049] (5) Preparation: Mix the filtered slurry in step (4) with 0.3% pectin.

[0050] (6) Homogenization: The mixture in step (5) was homogenized at 50 MPa for 10 min.

[0051] The comparative example adopted a common preparation method for cereal milk, and pectin as a stabilizer was added to improve the physical stability of the system.

[0052] The particle size distribution and average particle size D[3,2] of the embodiments and comparative examples are as follows: Figure 1The ball mill breaks up the large particles in the insoluble dietary fiber, and allows the micro-nano dietary fiber to stabilize the rice bran oil, preventing the oil droplets in the emulsion from aggregating and increasing. The rice bran beverage produced in the embodiment has a smaller average particle size, and the particle size distribution tends to be more monodisperse, which is conducive to the stability of the system.

[0053] The stability of the examples and comparative examples during storage is as follows: Figure 2 Despite the addition of the stabilizer, the rice bran beverage of the comparative example still showed obvious stratification after being placed at room temperature for 7 days, while the rice bran beverage of the embodiment remained stable after being placed at room temperature for 30 days, indicating that the rice bran beverage produced by the present invention has good physical stability.

[0054] The ABTS and DPPH free radical scavenging rates of the embodiments and comparative examples are as follows: Figure 3 As shown. Rice bran peptides prepared by enzymatic hydrolysis have been proven to be an excellent antioxidant, and crushing rice bran is also conducive to the release of active ingredients such as vitamin E, polyphenols, and flavonoids. Compared with the comparative example, the ABTS free radical scavenging rate of the example is significantly increased, and the DPPH scavenging rate is slightly increased, indicating that the rice bran beverage produced in the example has higher antioxidant properties.

[0055] It should be noted that in other embodiments of the present invention, other different schemes obtained by making specific selections within the scope of the steps, components, ratios, and process parameters recorded in the present invention can all achieve the technical effects recorded in the present invention, so the present invention will no longer list them one by one.

[0056] The invention is suitable for the general public, has a strong grain aroma, is light yellow, has a delicate taste, no graininess, and is rich in nutrition. Compared with other inventions, the invention degrades phytic acid by enzymatic hydrolysis to remove anti-nutritional factors; at the same time, the rice bran protein is degraded into rice bran peptides, thereby enhancing the physiological activities of the rice bran beverage such as anti-oxidation and anti-free radicals; and a ball mill is used to physically modify the dietary fiber, thereby retaining the health effects of the fiber, improving the taste and improving the physical stability of the rice bran beverage; finally, rice bran oil is added to provide the rice bran beverage with a strong taste and rich fat-soluble nutrients, giving full play to the functional value and nutritional value of rice bran oil, protein and fiber. Compared with the existing technology, the rice bran beverage prepared by the invention has a more uniform particle size, and can effectively improve the taste, texture and stability of rice bran. The prepared rice bran beverage has high content of dietary fiber, polypeptides and fat-soluble active ingredients, and has comprehensive nutritional value. The production process of the invention has no waste, and is suitable as a good utilization channel for rice by-products.

[0057] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a whole rice bran beverage, characterized in that: The following steps are involved: (1) coarse grinding: removing impurities from defatted rice bran, crushing and sieving to obtain rice bran powder with a mesh size of more than 300; (2) enzyme treatment: the rice bran powder obtained in step (1) is mixed with water, and enzymatically treated with phytase and alkaline protease to obtain an enzymatic solution; (3) Centrifugation: centrifuging the enzymatic hydrolyzate obtained in step (2) to obtain a supernatant and a precipitate, wherein the supernatant is the rice bran peptide extract; the centrifugation conditions are: 2000-4000g, and the centrifugation time is 5-20 minutes; (4) fine grinding: grinding the precipitate obtained in step (3) to obtain micro-nano bran dietary fiber; (5) Blending and homogenizing: Blending and homogenizing are performed in one of the following two ways to obtain a whole rice bran beverage: (a) 100 parts by weight of a rice bran peptide extract, 2-8 parts by weight of micro-nano bran dietary fiber and 5-10 parts by weight of rice bran oil are mixed and dispersed at high speed, and then homogenized under high pressure to form a Pickering emulsion; (b) mixing 2-8 parts by weight of micro-nano bran dietary fiber and the same part by weight of rice bran peptide extract and grinding for 5-10 minutes, then mixing the mixture with 92-98 parts by weight of additional rice bran titanium extract and 5-10 parts by weight of rice bran oil, dispersing at high speed, and then homogenizing under high pressure to form a Pickering emulsion; The total added amount of the rice bran titanium extract is 100 parts by weight.

2. The method for preparing a rice bran beverage according to claim 1, wherein The high-speed dispersion conditions in step (5) are a rotation speed of 10000-15000 rpm and a time of 1-4 minutes.

3. The method for preparing a rice bran beverage according to claim 1, wherein The homogenization conditions in step (5) are a homogenization pressure of 30-60 MPa and a homogenization time of 5-12 minutes.

4. The method for preparing a rice bran beverage according to claim 1, wherein The material-liquid ratio of rice bran to water in step (2) is 1 part by weight of rice bran to 5-20 parts by weight of water.

5. The method for preparing the rice bran beverage according to claim 1, characterized in that: The amount of phytase used in step (2) is 1-10 parts by weight of phytase per 1000 parts by weight of rice bran; the phytase treatment conditions are pH 4-7, the treatment temperature is 45-65° C., the treatment time is 0.5-4 hours, the enzyme inactivation temperature is 90-100° C., and the enzyme inactivation time is 5-15 minutes; The protease in step (2) is one or a mixture of neutral protease, papain, alkaline protease and trypsin, and the amount of the protease is 2-20 parts by weight of protease for 1000 parts by weight of rice bran; the protease treatment conditions in step (2) are pH 5-9, the treatment temperature is 40-60°C, the treatment time is 0.5-3 hours, the enzyme inactivation temperature is 90-100°C, and the enzyme inactivation time is 5-15 minutes.

6. The method for preparing the rice bran beverage according to claim 5, characterized in that: The reagent used for pH adjustment in step (2) is 1M sodium hydroxide solution and / or 1M hydrochloric acid.

7. The method for preparing the rice bran beverage according to claim 1, characterized in that: The grinding equipment in step (4) is a planetary ball mill, the rotation speed of the ball mill is 200-500rpm, the grinding time is 15-90 minutes, and the diameter and number of agate grinding balls in the ball mill are 40 of 5mm and 16 of 10mm respectively.

8. The method for preparing the rice bran beverage according to claim 1, characterized in that: The sieve used in step (1) is 5-300 mesh.

9. The method for preparing the rice bran beverage according to claim 1, characterized in that: The particle size of the micro-nano bran dietary fiber is 50-15 μm.

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