Rice milk powder and preparation method thereof

Abstract

The invention discloses a rice milk powder and a preparation method thereof, the preparation method comprising the following steps: S1. crushing; S2. enzymolysis; S3. enzyme inactivation; S4. grinding; S5. homogenization; S6. blending; S7. homogenization; S8. spray drying. In the step S6. blending, a blending agent is added to the homogenized grinding liquid, the blending agent comprising refined coconut oil, milk powder, dipotassium hydrogen phosphate and sodium hexametaphosphate; the addition amount of refined coconut oil is 25-35% of the mass of rice powder, the addition amount of milk powder is 8-15% of the mass of rice powder, the addition amount of dipotassium hydrogen phosphate is 1.5-2.0% of the mass of rice powder, and the addition amount of sodium hexametaphosphate is 0.2-0.5% of the mass of rice powder. The rice milk powder prepared by the invention has both nutrition and taste, good stability and dispersibility, the preparation process of the invention is simple to operate, the rice slurry has good fluidity during the preparation process, and is suitable for industrial production.

Description

Technical Field

[0001] The invention specifically relates to rice milk powder and a preparation method thereof. Background Art

[0002] Rice is a high-quality plant protein. It is not only rich in nutrients, but also has the characteristics of low antigen and low allergenicity. The rice starch layer contains trace elements and proteins required by the human body. Rice is also rich in carbohydrates, dietary fiber and other nutrients, which are suitable for the physiological needs of various consumer groups.

[0003] Rice milk powder is a new rice flour product. Generally, rice is prepared into rice milk powder by fermentation process. For example, patents CN109511876A and CN111418760A disclose the preparation method of rice milk powder, and its process is roughly as follows: rice soaking → grinding → filtering → sterilization → enzymolysis → preparation → homogenization → concentration → spray drying. Due to the easy gelatinization of rice starch, the prior art controls the rice concentration to be lower during grinding to ensure the smooth progress of subsequent steps such as filtration, but therefore needs to concentrate the feed liquid before spray drying to reduce the moisture in the feed liquid. In addition, rice slurry filtration can cause the loss of nutrients in a large amount of rice, and not filtering can make the rice milk powder taste rougher and have poor stability. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing rice milk powder which has both nutrition and taste, good stability and is suitable for industrial production.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention is to provide a method for preparing rice milk powder, comprising the following steps:

[0007] S1. Crushing: crushing the rice to obtain rice powder;

[0008] S2. Enzymolysis: mixing the rice powder, water and amylase to obtain an enzymolysis solution;

[0009] S3. Enzyme inactivation: enzyme inactivation after enzymolysis;

[0010] S4. Refining: grinding the enzymatic solution after the enzyme is inactivated to form a grinding solution;

[0011] S5. Homogenizing: homogenizing the grinding liquid;

[0012] S6. Preparation: The homogenized grinding liquid is mixed and sheared with the preparation agent to obtain a preparation liquid;

[0013] S7. Homogenizing: homogenizing the prepared liquid;

[0014] S8. Spray drying: The homogenized formulation is spray dried to obtain the rice milk powder;

[0015] The formulation comprises refined coconut oil, milk powder, dipotassium hydrogen phosphate and sodium hexametaphosphate; the addition amount of the refined coconut oil is 25-35% of the mass of the rice powder, the addition amount of the milk powder is 8-15% of the mass of the rice powder, the addition amount of the dipotassium hydrogen phosphate is 1.5-2.0% of the mass of the rice powder, and the addition amount of the sodium hexametaphosphate is 0.2-0.5% of the mass of the rice powder.

[0016] Preferably, the added amount of the refined coconut oil is 26-32% of the mass of the rice powder, for example 26.5%, 27.0%, 27.5%, 28.0%, 28.5%, 29.0%, 29.5%, 30.0%, 30.5%, 31.0%, 31.5%, etc.

[0017] Further preferably, the added amount of the refined coconut oil is 26-30% of the mass of the rice powder.

[0018] Preferably, the added amount of the milk powder is 9-15% of the mass of the rice powder, for example 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, etc.

[0019] Further preferably, the added amount of the milk powder is 10-15% of the mass of the rice powder.

[0020] Preferably, the added amount of the dipotassium hydrogen phosphate is 1.6-2.0% of the mass of the rice powder, for example, 1.65%, 1.70%, 1.75%, 1.80%, 1.85%, 1.90%, 1.95%, etc.

[0021] Further preferably, the added amount of the dipotassium hydrogen phosphate is 1.7-1.9% of the mass of the rice powder.

[0022] Preferably, the addition amount of the sodium hexametaphosphate is 0.2-0.4% of the mass of the rice powder, for example, 0.24%, 0.26%, 0.30%, 0.32%, 0.34%, 0.36%, 0.38%, 0.40%, etc.

[0023] Further preferably, the added amount of the sodium hexametaphosphate is 0.3-0.4% of the mass of the rice powder.

[0024] Preferably, in step S2, the mass of the rice powder is 35% to 45% of the total mass of the rice powder, the water and the amylase, for example, 36.0%, 37.0%, 38.0%, 39.0%, 40.0%, 41.0%, 42.0%, 43.0%, 44.0%, etc.

[0025] Further preferably, in step S2, the mass of the rice powder is 38% to 45% of the total mass of the rice powder, the water and the amylase.

[0026] More preferably, in step S2, the mass of the rice powder is 38% to 42% of the total mass of the rice powder, the water and the amylase.

[0027] Preferably, in step S2, the amount of amylase added is 0.6% to 1.0% of the mass of the rice powder, for example, 0.65%, 0.70%, 0.75%, 0.80%, 0.85%, 0.90%, 0.95%, etc.

[0028] Further preferably, in step S2, the amount of the amylase added is 0.7% to 1.0% of the mass of the rice powder.

[0029] More preferably, in step S2, the amount of amylase added is 0.7% to 0.9% of the mass of the rice powder.

[0030] Preferably, in step S2, the amylase comprises α-amylase.

[0031] Preferably, the temperature of the enzymatic hydrolysis is controlled to be 65-67°C, for example, 65.5°C, 66°C, 66.5°C, 67°C, etc.

[0032] Preferably, the enzymatic hydrolysis time is 15 to 40 min, for example, 16 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, etc.

[0033] More preferably, the enzymatic hydrolysis time is 25 min to 35 min.

[0034] More preferably, the enzymatic hydrolysis time is 28 min to 32 min.

[0035] Preferably, the enzyme inactivation temperature is controlled to be 90-95°C, such as 91°C, 92°C, 93°C, 94°C, 95°C, etc.

[0036] More preferably, the temperature for inactivating the enzyme is controlled at 90-93°C.

[0037] Preferably, the enzyme inactivation time is 10 to 15 minutes, for example, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, etc.

[0038] More preferably, the enzyme inactivation time is 10 to 13 minutes.

[0039] Preferably, in step S4, the grinding is performed after the temperature of the enzymatic hydrolyzate after the enzyme is inactivated is controlled to be 50-60°C, for example, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, etc.

[0040] Further preferably, in step S4, the grinding is performed after the temperature of the enzymatic hydrolyzate after the enzyme is inactivated is controlled to be 50-55°C.

[0041] Preferably, in step S5, the homogenization is carried out under the condition of 250-350 bar, for example, 260 bar, 280 bar, 300 bar, 320 bar, 340 bar, etc.

[0042] Further preferably, in step S5, the homogenization is performed under the condition of 250-320 bar.

[0043] More preferably, in step S5, the homogenization is performed under the condition of 250-310 bar.

[0044] Preferably, in step S7, the homogenization is carried out under the condition of 250-300 bar, for example, 260 bar, 270 bar, 280 bar, 290 bar, 300 bar, etc.

[0045] Further preferably, in step S7, the homogenization is performed under the condition of 270-300 bar.

[0046] Preferably, the inlet air temperature of the spray drying is controlled to be 170-190°C, such as 175°C, 180°C, 185°C, etc.

[0047] Preferably, the outlet air temperature of the spray drying is controlled to be 80-90°C, for example, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, etc.

[0048] Preferably, at least 80% of the rice powder has a particle size of less than 60 mesh.

[0049] Preferably, the rice is selected from one or more of common polished rice, polished rice and glutinous rice.

[0050] Further preferably, the rice is selected from common japonica rice.

[0051] Preferably, the milk powder comprises skim milk powder or whole milk powder.

[0052] The second aspect of the present invention is to provide a rice milk powder, which is prepared by any of the above-mentioned preparation methods.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] The rice milk powder prepared by the invention through improving the whole preparation process has both nutrition and taste, and has good stability and dispersibility; the preparation method of the rice milk powder provided by the invention can reduce the viscosity of rice while ensuring the sweetness of the rice milk powder; the technical scheme of the invention can make the rice have good fluidity even at a high concentration, which is convenient for transportation in the production process, and the increase of energy consumption due to concentration in the later stage is avoided; the preparation method does not have a slag removal and filtering process, the preparation process is simple to operate, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of the process flow of the present invention;

[0056] Figure 2 Particle size distribution curves in Example 1 and Comparative Example 1;

[0057] Figure 3 Comparative diagram of the stability of rice milk powder in Example 1 and Comparative Example 2, with Example 1 on the left and Comparative Example 2 on the right;

[0058] Figure 4 Comparative diagram of the stability of rice milk powders in Example 1 and Comparative Example 3, with Example 1 on the left and Comparative Example 3 on the right. DETAILED DESCRIPTION

[0059] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0060] The present invention provides a method for preparing rice milk powder, comprising the following steps:

[0061] S1. Crushing: crushing the rice to obtain rice powder;

[0062] S2. Enzymatic hydrolysis: mixing rice powder, water and amylase to obtain an enzymatic hydrolyzate;

[0063] S3. Enzyme inactivation: enzyme inactivation after enzymolysis;

[0064] S4. Refining: grinding the enzymatic solution after the enzyme is inactivated to form a grinding solution;

[0065] S5. Homogenization: homogenizing the grinding liquid;

[0066] S6. Preparation: The homogenized grinding liquid is mixed and sheared with the preparation agent to obtain a preparation liquid;

[0067] S7. Homogenize: homogenize the prepared liquid;

[0068] S8. Spray drying: The homogenized formulation is spray dried to obtain rice milk powder;

[0069] Wherein, the blending agent includes refined coconut oil, milk powder, dipotassium hydrogen phosphate, sodium hexametaphosphate; the addition amount of refined coconut oil is 25-35% of the mass of rice powder, the addition amount of milk powder is 8-15% of the mass of rice powder, the addition amount of dipotassium hydrogen phosphate is 1.5-2.0% of the mass of rice powder, and the addition amount of sodium hexametaphosphate is 0.2-0.5% of the mass of rice powder. The rice milk powder prepared by the present invention through the improvement of the entire preparation process has both nutrition and taste, and has good stability and dispersibility; the preparation method of the rice milk powder of the present invention can reduce the viscosity of rice while ensuring the sweetness of the rice milk powder, and the technical scheme of the present invention can make the rice have good fluidity at high concentration, which is convenient for transportation in the production process, and at the same time avoids the increase of energy consumption in the later concentration, and the preparation method has no slag removal and filtering process, the preparation process is simple to operate, and is suitable for industrial production. If the preparation steps are adjusted, for example, refining is performed first and then enzymolysis is performed, continuous production cannot be achieved in large-scale industrial production, which is time-consuming and labor-intensive.

[0070] The present invention is further described in detail below with reference to specific embodiments.

[0071] In the present invention, unless otherwise specified, "%" represents mass percentage; the raw materials, reagents, etc. used are all conventional commercially available products.

[0072] Example 1

[0073] (1) Crushing: 400 kg of rice was crushed in a grinder to obtain rice flour, and it was required that more than 80% of the obtained rice flour could pass through a 60-mesh sieve.

[0074] (2) Enzymolysis: Add 600 kg of water and 3.2 kg of α-amylase into the enzymolysis tank, add 400 kg of rice flour, raise the temperature to 65°C to start enzymolysis, and perform enzymolysis for 30 min.

[0075] (3) Inactivation of enzymes: Raise the temperature to 90°C and keep warm for 10 min to inactivate enzymes.

[0076] (4) Grinding: The enzymatic hydrolysate is cooled to about 50°C and then passed through a colloid mill to obtain a grinding liquid.

[0077] (5) Homogenization: The obtained grinding liquid is homogenized at 300 bar.

[0078] (6) Preparation: 50 kg of skim milk powder, 110 kg of refined coconut oil, 7.5 kg of dipotassium hydrogen phosphate and 1.5 kg of sodium hexametaphosphate were added to the homogenized grinding liquid for shearing and preparation to obtain a prepared liquid.

[0079] (7) Homogenization: The prepared liquid was homogenized at 250 bar.

[0080] (8) Spray drying: The homogenized prepared liquid is spray dried, and the spray air inlet temperature is controlled to be 175° C. and the air outlet temperature is controlled to be 85° C. After spray drying, the liquid is packaged to obtain rice milk powder.

[0081] Comparative Example 1

[0082] The steps for preparing rice noodles in this comparative example are basically the same as those in Example 1, except that after refining in step (4), the grinding liquid is filtered with 100-mesh gauze, and then subsequent steps such as step (5) are performed after filtration.

[0083] Comparative Example 2

[0084] The steps for preparing rice noodles in this comparative example are basically the same as those in Example 1, except that the amounts of dipotassium hydrogen phosphate and sodium hexametaphosphate added to the homogenized grinding liquid in step (6) are different. In this comparative example, 2.5 kg of dipotassium hydrogen phosphate and 6.5 kg of sodium hexametaphosphate are added to the homogenized grinding liquid, and the amounts of other components added are the same as those in Example 1.

[0085] Comparative Example 3

[0086] The steps for preparing rice noodles in this comparative example are basically the same as those in Example 1, except that the amount of skimmed milk powder added to the homogenized grinding liquid in step (6) is different. In this comparative example, 14 kg of skimmed milk powder is added to the homogenized grinding liquid, and the amounts of other components added are the same as those in Example 1.

[0087] Result analysis:

[0088] The nutritional components and particle sizes of the rice milk powder prepared in Comparative Example 1 and Example 1 were compared.

[0089] The results of the comparison of the nutritional components of the rice milk powder prepared in Comparative Example 1 and Example 1 are shown in Table 1.

[0090] Table 1

[0091] Comparative Example 1 (de-slag rice milk powder) Embodiment 1 (non-slag-removing rice milk powder) protein(%) 4.1 8.5 Fat(%) 22.1 22.2

[0092] As shown in Table 1, the protein content of the unremoved rice powder is significantly higher than that of the removed rice powder. The rice powder prepared in Example 1 can well retain the nutritional components of the protein in rice.

[0093] The particle sizes of the rice milk powders prepared in Comparative Example 1 and Example 1 were measured using a MasterSizer particle size measuring instrument. The results are shown in Table 2.

[0094] Table 2

[0095] Comparative Example 1 (de-slag rice milk powder) Embodiment 1 (non-slag-removing rice milk powder) D(0.5)(μm) 7.688 4.429 D(0.9)(μm) 28.965 27.327 Volume average particle size (μm) 12.393 13.299

[0096] From Table 2 and Figure 2 It can be seen that there is no significant difference in particle size between the unde-de-crusted rice milk powder and the de-de-crusted rice milk powder, so the unde-de-crusted rice milk powder can also achieve the smoothness of the de-de-crusted rice milk powder.

[0097] The sugar content of the rice milk powder prepared in Example 1 was tested, and the test results are shown in Table 3.

[0098] Table 3

[0099] Example 1 (%) fructose 0 glucose 5.1 sucrose 0 maltose 22.6 lactose 6.7

[0100] As can be seen from Table 3, the un-slag-removed rice milk powder of the present invention does not contain sucrose, but has high contents of glucose and maltose, and can meet the overall sweetness requirement of the rice milk powder.

[0101] The dissolution and stability of the rice milk powder prepared in Example 1, Comparative Example 2 and Comparative Example 3 were tested. The rice milk powder prepared in Example 1, Comparative Example 2 and Comparative Example 3 were respectively dissolved in water above 85°C, wherein the mass ratio of rice milk powder to water was 1:6. After standing for 10 minutes, the rice milk powder of Example 1 and Comparative Example 2 was observed. The results are shown in FIG. Figure 3 , observe the rice milk powder of embodiment 1 and comparative example 3, the result is shown Figure 4 .

[0102] Depend on Figure 3 It can be seen that the rice milk powder prepared in Comparative Example 2 undergoes significant precipitation and stratification after standing for 10 minutes, while the rice milk powder prepared in Example 1 does not undergo stratification. Figure 4It can be seen that the rice milk powder prepared by mixing the formula of comparative example 3, after standing for 10min, significant stratification occurs, while the rice milk powder prepared by embodiment 1 does not undergo stratification, indicating that the rice milk powder prepared by the present invention has good stability. The contents of dipotassium hydrogen phosphate, sodium hexametaphosphate and skimmed milk powder have a great influence on the stability of rice milk powder. The contents of the three should be added according to a certain ratio to make the rice milk powder prepared have good stability, specifically, the addition of milk powder is 8-15% of the mass of rice powder, the addition of dipotassium hydrogen phosphate is 1.5-2.0% of the mass of rice powder, and the addition of sodium hexametaphosphate is 0.2-0.5% of the mass of rice powder. When the contents of the three are too low or too high, the stability of rice milk powder is poor or affects its mouthfeel, for example, when the content of skimmed milk powder is too low, significant stratification occurs in rice milk powder, and when the content of skimmed milk powder is too high, the milk taste of rice milk powder is too heavy, and the characteristic fragrance of rice is insufficient.

[0103] The rice milk powder prepared by the invention through improving the whole preparation process has both nutrition and taste, and has good stability and dispersibility. The preparation method of the rice milk powder provided by the invention can reduce the viscosity of rice while ensuring the sweetness of the rice milk powder. The technical scheme of the invention can make the rice have good fluidity even at a high concentration, which is convenient for transportation in the production process, and the increase of energy consumption due to concentration in the later stage is avoided. The preparation method does not have a slag removal and filtering process, the preparation process is simple to operate, and is suitable for industrial production.

[0104] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing rice milk powder, characterized in that, The following steps are involved: S1. Crushing: crushing the rice to obtain rice powder; S2. Enzymolysis: mixing the rice powder, water and amylase to obtain an enzymolysis solution; the mass of the rice powder is 35% to 45% of the total mass of the rice powder, the water and the amylase; S3. Enzyme inactivation: enzyme inactivation after enzymolysis; S4. Refining: grinding the enzymatic solution after the enzyme is inactivated to form a grinding solution; S5. Homogenizing: homogenizing the grinding liquid; S6. Preparation: The homogenized grinding liquid is mixed and sheared with the preparation agent to obtain a preparation liquid; S7. Homogenizing: homogenizing the prepared liquid; S8. Spray drying: The homogenized formulation is spray dried to obtain the rice milk powder; The blending agent comprises refined coconut oil, milk powder, dipotassium hydrogen phosphate and sodium hexametaphosphate; the amount of the refined coconut oil added is 25-35% of the mass of the rice powder, the amount of the milk powder added is 8-15% of the mass of the rice powder, the amount of the dipotassium hydrogen phosphate added is 1.5-2.0% of the mass of the rice powder, and the amount of the sodium hexametaphosphate added is 0.2-0.5% of the mass of the rice powder; The preparation method does not require a slag removal and filtering process.

2. The preparation method according to claim 1, characterized in that: In step S2, the amount of the amylase added is 0.6% to 1.0% of the mass of the rice powder; and / or, in step S2, the amylase includes α-amylase.

3. The preparation method according to claim 1 or 2, characterized in that: The temperature of the enzymolysis is controlled to be 65-67° C., and the time of the enzymolysis is 15-40 minutes.

4. The preparation method according to claim 1, characterized in that: The temperature of the enzyme inactivation is controlled to be 90-95° C., and the time of the enzyme inactivation is 10-15 minutes.

5. The preparation method according to claim 1, characterized in that: In step S4, the temperature of the enzymatic hydrolyzate after the enzyme inactivation is controlled to be 50-60° C. before the grinding is performed.

6. The preparation method according to claim 1, characterized in that: In step S5, the homogenization is performed at 250-350 bar; and / or, in step S7, the homogenization is performed at 250-300 bar.

7. The preparation method according to claim 1, characterized in that: The inlet air temperature of the spray drying is controlled to be 170-190°C, and the outlet air temperature is controlled to be 80-90°C.

8. The preparation method according to claim 1, characterized in that: At least 80% of the rice powder has a particle size of less than 60 mesh.

9. The preparation method according to claim 1, characterized in that: The rice is selected from one or more of common polished round-grained rice, glutinous rice and glutinous rice; and / or the milk powder includes skimmed milk powder or whole milk powder.

10. A rice milk powder, characterized in that The rice milk powder is prepared by the preparation method according to any one of claims 1 to 9.

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