Preparation method of whole wheat germ milk

Abstract

The invention discloses a preparation method of whole wheat germ milk, which comprises the following steps: (1) mixing wheat germ, high-temperature alpha-amylase and water, and grinding at 85-95 DEG C; (2) cooling the feed liquid obtained in the step (1) to 55-60 DEG C, adding medium-temperature alpha-amylase, glucamylase and protease, and carrying out enzymolysis at 55-60 DEG C; (3) raising the temperature of the material liquid after enzymolysis to 85-95 DEG C, and keeping the temperature at 85-95 DEG C for 10-15 minutes; (4) cooling the material liquid in the step (3) to 60-70 DEG C, and homogenizing at 60-70 DEG C; (5) carrying out high-pressure microjet treatment on the homogenized material liquid at the temperature of between 60 and 70 DEG C and at the pressure of between 1,000 and 1,500 bar; and (6) mixing the feed liquid subjected to high-pressure microjet treatment with dipotassium phosphate and microcrystalline cellulose, and performing shearing, homogenizing and high-temperature sterilization to obtain the whole wheat germ milk.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for preparing whole wheat germ milk. Background Art

[0002] Wheat germ contains rich protein, unsaturated fatty acids, vitamin E, vitamin B1, dietary fiber and essential amino acids for the human body, among which the lysine content of wheat germ is 6 to 7 times higher than that of rice and white flour, and is a highly nutritious natural food. Since wheat germ contains rich protein, it can be used as a plant protein raw material for the development of plant protein beverages to replace dairy products prepared from animal milk sources. In order to ensure a delicate and smooth taste, the existing wheat germ beverages have a slag removal process in the preparation process, which greatly loses the nutritional value of wheat germ and does not belong to the true whole wheat germ milk product. Patent CN201010524419.9 provides a method for preparing a wheat germ beverage, in which the particle size of the feed liquid reaches 200 to 300 meshes by fine grinding with a colloid mill, so that the slag removal process is not performed and the nutritional components of wheat germ are retained. However, the wheat germ protein beverage obtained in this way still contains a large amount of insoluble solids, which is not conducive to the stability of the product. The slag feeling of the beverage will also increase in the later storage period, and the wheat germ concentration in the wheat germ beverage is not high. Moreover, in order to ensure the taste of wheat germ milk, the existing process will add exogenous white sugar for flavoring during the preparation process, which is not friendly to some people. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing high-concentration whole wheat germ milk with good stability.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A method for preparing whole wheat germ milk, the method comprising the following steps:

[0006] (1) mixing wheat germ, high temperature α-amylase and water, and grinding at 85-95° C.;

[0007] (2) cooling the liquid of step (1) to 55-60° C., adding medium-temperature α-amylase, glucoamylase and protease for enzymolysis at 55-60° C.;

[0008] (3) raising the temperature of the enzymatically hydrolyzed liquid to 85-95° C. and keeping the temperature at 85-95° C. for 10-15 minutes;

[0009] (4) cooling the liquid of step (3) to 60-70° C. and homogenizing at 60-70° C.;

[0010] (5) subjecting the homogenized liquid to high-pressure microfluidization treatment at 1000-1500 bar at 60-70° C.;

[0011] (6) The slurry after high-pressure microfluidization treatment is mixed with dipotassium hydrogen phosphate and microcrystalline cellulose, and the whole wheat germ milk is obtained by shearing, homogenizing and high-temperature sterilization.

[0012] Preferably, the wheat germ is fresh wheat germ with a water content of 10wt% to 14wt%.

[0013] Preferably, in step (1), the mass ratio of the wheat germ to water is 1:(3.5-6).

[0014] The mass of the high temperature α-amylase is 0.5% to 1.5% of the mass of the wheat germ.

[0015] Preferably, in step (1), the D90 of the slurry after refining is 450-550 μm.

[0016] Preferably, the refining time is 20 to 50 minutes.

[0017] Preferably, the protease in step (2) is one or more of neutral protease, chymosin, aminopeptidase, and glutaminase.

[0018] Preferably, the enzymatic hydrolysis time in step (2) is 1.5 to 3 hours.

[0019] Preferably, the mass of the medium-temperature α-amylase in step (2) is 0.5% to 1.5% of the mass of the wheat germ in step (1), the mass of the glucoamylase in step (2) is 0.4% to 0.6% of the mass of the wheat germ in step (1), and the mass of the protease in step (2) is 0.5% to 1.5% of the mass of the wheat germ in step (1).

[0020] Preferably, the high-temperature α-amylase activity is 104400-127600 U / g, the medium-temperature α-amylase activity is 11700-14300 U / g, the glucoamylase activity is 5850-7150 U / g, the neutral protease activity is 72000-88000 U / g, the chymosin activity is 67500-82500 U / g, the aminopeptidase activity is 450-550 U / g, and the glutaminase activity is 450-550 U / g.

[0021] Preferably, the amount of dipotassium hydrogen phosphate used in step (6) is 0.1%-0.3% of the total mass of the whole wheat germ milk.

[0022] Preferably, the amount of microcrystalline cellulose used in step (6) is 0.1%-0.2% of the total mass of the whole wheat germ milk.

[0023] Preferably, the temperature of high temperature sterilization in step (6) is 85°C to 90°C, and the time is 10 to 15 minutes.

[0024] Preferably, the D90 of the slurry after homogenization in step (3) is 190-250 μm; the D90 of the slurry after high-pressure microfluidization treatment is 50-80 μm; and the D90 of the slurry after homogenization in step (6) is 50-80 μm.

[0025] Preferably, the D90 of the slurry after homogenization in step (3) is 190-215 μm; the D90 of the slurry after high-pressure microfluidization treatment is 60-70 μm; and the D90 of the slurry after homogenization in step (6) is 60-70 μm.

[0026] Preferably, the homogenization pressures in step (4) and step (6) are respectively 250 to 300 bar.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The present invention optimizes the preparation method, without removing the slag from the liquid and without adding exogenous sugar, so that the final whole wheat germ milk can ensure the taste and also have good stability. The preparation method of the present invention can increase the refining concentration and efficiently produce high-concentration whole wheat germ milk, which is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a graph showing the stability test results of whole wheat germ milk of Example 1, Example 2, Comparative Example 4 and Comparative Example 5. DETAILED DESCRIPTION

[0030] In the preparation process of existing wheat germ drinks, ≥100 mesh filtration or deslagging process is basically used to deslagging the liquid feed, so as to achieve good smoothness and stability, but this will inevitably cause the loss of wheat germ nutrients. In order to solve the above problems, the inventors of the present application use enzymatic hydrolysis combined with high-pressure micro-jetting to treat the liquid feed. By optimizing the preparation method, a high-concentration wheat germ milk is obtained without deslagging the liquid feed, so that the final wheat germ milk can have good stability and comprehensive nutritional value while ensuring the taste. Specifically, the technical solution of the present application is as follows:

[0031] (1) mixing wheat germ, high temperature α-amylase and water, and grinding at 85-95° C.;

[0032] (2) cooling the liquid of step (1) to 55-60° C., adding medium-temperature α-amylase, glucoamylase and protease for enzymolysis at 55-60° C.;

[0033] (3) raising the temperature of the enzymatically hydrolyzed liquid to 85-95° C. and keeping the temperature at 85-95° C. for 10-15 minutes;

[0034] (4) cooling the liquid of step (3) to 60-70° C. and homogenizing at 60-70° C.;

[0035] (5) subjecting the homogenized liquid to high-pressure microfluidization treatment at 1000-1500 bar at 60-70° C.;

[0036] (6) The slurry after high-pressure microfluidization treatment is mixed with dipotassium hydrogen phosphate, microcrystalline cellulose and water, and the whole wheat germ milk is obtained by shearing, homogenizing and high-temperature sterilization.

[0037] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and comparative examples.

[0038] The water content of the fresh wheat germs used in the following examples and comparative examples is in the range of 10 wt % to 14 wt %.

[0039] The enzymes used in the following examples and comparative examples are all commercially available products, the high temperature α-amylase activity is 116000 U / g, the medium temperature α-amylase activity is 13000 U / g, the glucoamylase activity is 6500 U / g, the neutral protease activity is 80000 U / g, the aminopeptidase activity is 500 U / g, and the glutaminase activity is 500 U / g.

[0040] The D90 of the slurries after different treatments in the following examples and comparative examples was measured using a MasterSizer particle size analyzer.

[0041] Example 1

[0042] This embodiment provides a method for preparing whole wheat germ milk, which is as follows:

[0043] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 523.831 μm.

[0044] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, and 0.8 kg of glutaminase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0045] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0046] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 204.624 μm.

[0047] (5) High-pressure microfluidization: The homogenized liquid is treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid is 67.822 μm.

[0048] (6) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization and shear and prepare. The preparation temperature is 65°C.

[0049] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 66.612 μm.

[0050] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0051] Example 2

[0052] This embodiment provides a method for preparing whole wheat germ milk, which is as follows:

[0053] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 519.235 μm.

[0054] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, 0.2 kg of neutral protease and 0.2 kg of aminopeptidase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0055] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0056] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 198.421 μm.

[0057] (5) High-pressure microfluidization: The homogenized liquid is treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid is 64.525 μm.

[0058] (6) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization and shear and prepare. The preparation temperature is 65° C.

[0059] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 63.972 μm.

[0060] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0061] Comparative Example 1

[0062] This comparative example provides a method for preparing wheat germ milk, which is as follows:

[0063] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 528.611 μm.

[0064] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, and 0.8 kg of glutaminase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0065] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0066] (4) Deslagging: The temperature of the liquid after enzyme inactivation was lowered to 65°C, and the D90 of the liquid after deslagging was 107.814 μm;

[0067] (5) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the filtered filtrate and shear and prepare at a preparation temperature of 65° C.

[0068] (6) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 56.061 μm.

[0069] (7) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0070] Comparative Example 2

[0071] This comparative example provides a method for preparing whole wheat germ milk, which is as follows:

[0072] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 504.781 μm.

[0073] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, and 0.8 kg of glutaminase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0074] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0075] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 197.002 μm.

[0076] (5) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization and shear and prepare at a preparation temperature of 65° C.

[0077] (6) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 190.591 μm.

[0078] (7) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0079] Comparative Example 3

[0080] This comparative example provides a method for preparing whole wheat germ milk, which is as follows:

[0081] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 4 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 522.308 μm.

[0082] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 0.5 kg of medium-temperature α-amylase and 0.8 kg of glutaminase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0083] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0084] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 205.934 μm.

[0085] (5) High-pressure microfluidization: The homogenized liquid is treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid is 68.169 μm.

[0086] (6) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization and shear and prepare at a preparation temperature of 65° C.

[0087] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 66.184 μm.

[0088] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0089] Comparative Example 4

[0090] This comparative example provides a method for preparing whole wheat germ milk, which is as follows:

[0091] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 499.567 μm.

[0092] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase and 1 kg of glucoamylase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0093] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0094] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 210.441 μm.

[0095] (5) High-pressure microfluidization: The homogenized liquid was treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid was 70.581 μm.

[0096] (6) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization and shear and prepare at a preparation temperature of 65°C

[0097] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 68.245 μm.

[0098] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0099] Comparative Example 5

[0100] This comparative example provides a method for preparing whole wheat germ milk, which is as follows:

[0101] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 518.426 μm.

[0102] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, and 0.8 kg of glutaminase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0103] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0104] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 209.612 μm.

[0105] (5) High-pressure microfluidization: The homogenized liquid is treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid is 71.994 μm.

[0106] (6) Preparation: Add 3.8 kg of dipotassium hydrogen phosphate and 0.2 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization, shear and prepare, and the preparation temperature is 65° C.

[0107] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 67.103 μm.

[0108] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0109] Comparative Example 6

[0110] This comparative example provides a method for preparing whole wheat germ milk, which is as follows:

[0111] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of medium-temperature α-amylase were circulated and refined at 65°C for 30 min. The D90 of the refined liquid was 524.105 μm.

[0112] (2) Enzymatic hydrolysis: cool the liquid to 58°C, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, and 0.8 kg of glutaminase, and perform enzymatic hydrolysis at 58°C for 1 h;

[0113] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0114] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 205.477 μm.

[0115] (5) High-pressure microfluidization: The homogenized liquid is treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid is 68.406 μm.

[0116] (6) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization, shear and prepare, and the preparation temperature is 65° C.

[0117] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 66.211 μm.

[0118] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0119] Comparative Example 7

[0120] This comparative example provides a method for preparing whole wheat germ milk, which is as follows:

[0121] (1) Refining: 200 kg of fresh wheat germ, 800 kg of water and 2 kg of high temperature α-amylase were refining at 90°C for 30 min. The D90 of the refining liquid was 509.462 μm.

[0122] (2) Enzymatic hydrolysis: cool the liquid to 58°C, adjust the pH to 7.5 with supernatant, add 2 kg of medium-temperature α-amylase, 1 kg of glucoamylase, and 0.4 kg of alkaline protease, and perform enzymatic hydrolysis at 58°C for 1 h;

[0123] (3) Inactivation of enzyme: After the enzymatic hydrolysis is completed, the temperature is raised to 90°C to inactivate the enzyme for 10 min;

[0124] (4) Homogenization: The inactivated enzyme solution was cooled to 65°C and homogenized at 65°C and 300 bar. The D90 of the homogenized solution was 199.160 μm.

[0125] (5) High-pressure microfluidization: The homogenized liquid was treated with high-pressure microfluidization at 65°C and 1200 bar. The D90 of the treated liquid was 66.819 μm.

[0126] (6) Preparation: Add 3 kg of dipotassium hydrogen phosphate and 1 kg of microcrystalline cellulose to the liquid after high-pressure microfluidization, shear and prepare, and the preparation temperature is 65° C.

[0127] (7) Homogenization: The sheared prepared liquid is homogenized at a homogenization pressure of 300 bar. The D90 of the homogenized liquid is 65.320 μm.

[0128] (8) Sterilization: The homogenized prepared solution is sterilized at high temperature at 85°C for 15 minutes.

[0129] The nutritional components of the whole wheat germ milk of Example 1 and the wheat germ milk of Comparative Example 1 are compared in Table 1.

[0130] Table 1

[0131] Example 1 Example 2 Comparative Example 1 Lysine (wt%) 0.42 0.40 0.16 Protein (wt%) 5.3 5.1 2.8 Fat (wt%) 1.5 1.5 1.3 Unsaturated fatty acids (wt%) 1.10 1.02 0.98 Vitamin E (mg / 100g) 6.30 6.07 4.45

[0132] The content of each nutrient in Table 1 is tested according to the following standards:

[0133] Lysine: GB 5009.124-2016 National Food Safety Standard Determination of Amino Acids in Food;

[0134] Protein: GB 5009.5-2016 National Food Safety Standard Determination of Protein in Food;

[0135] Fat: GB 5009.6-2016 National Food Safety Standard Determination of Fat in Food;

[0136] Unsaturated fatty acids: GB 5009.168-2016 National Food Safety Standard Determination of fatty acids in foods;

[0137] Vitamin E: GB 5009.82-2016 National Food Safety Standard Determination of Vitamins A, D and E in Foods.

[0138] The glucose and maltose contents of the whole wheat germ milks of Examples 1 to 2 and Comparative Examples 2 to 5 are shown in Table 2. Except for Comparative Example 3, no additional sweeteners such as exogenous white sugar or the like are required to be added to the rest of the whole wheat germ milks.

[0139] Table 2

[0140]

[0141]

[0142] Note: ND means the test result is below the detection limit

[0143] The detection of maltose and glucose content refers to GB 5009.8-2016 National Food Safety Standard Determination of Fructose, Glucose, Sucrose, Maltose and Lactose in Food.

[0144] The stability test results of whole wheat germ milk of Example 1, Example 2, Comparative Example 4 and Comparative Example 5 are shown in Figure 1 , Figure 1 From left to right in the figure are the states of the whole wheat germ milk of Example 1, Example 2, Comparative Example 4 and Comparative Example 5 after standing at 4°C for 12 hours.

[0145] According to the above test results, Example 1 and Example 2 provide whole wheat germ milk with comprehensive nutrition, good taste and good stability. In addition, it was also found in the research and development that fresh wheat germ is very easy to absorb water and swell in water, and the high starch content makes it easy to gelatinize during processing, increasing the viscosity of the system and increasing the difficulty and time of later preparation. Although the amount of water can be increased during refining to reduce the viscosity of the system, or water can be added during preparation to reduce the difficulty of preparation, these operations all lead to a decrease in the concentration of the whole wheat germ milk product. In the refining process of Example 1 and Example 2, high-temperature α-amylase liquefies and enzymolyzes the material, effectively reducing the viscosity of the system, facilitating later preparation, and increasing the concentration of the prepared whole wheat germ milk. Example 1 and Example 2 can increase the refining concentration, improve production efficiency, and are suitable for large-scale industrial production.

[0146] Comparative Example 1 adopts conventional filtering and deslagging, resulting in serious loss of protein, vitamin E and lysine, and the nutritional value is significantly lower than that of whole wheat germ milk.

[0147] Comparative Example 2 did not undergo high-pressure microfluidization treatment, and the prepared whole wheat germ milk had a larger particle size and a rougher taste.

[0148] In Comparative Example 3, no glucoamylase was used in the enzymatic hydrolysis process, and the glucose content of the prepared whole wheat germ milk was significantly reduced, resulting in a lower sweetness of the product, and the tasters reported that the flavor was poor.

[0149] In Comparative Example 4, glutaminase was not used in the enzymatic hydrolysis process, and the stability of the prepared whole wheat germ milk was poor. After standing at 4° C. for 12 hours, serious oil-water stratification occurred.

[0150] In comparative example 5, during the later preparation process, the amount of potassium dihydrogen phosphate was increased and the amount of microcrystalline cellulose was reduced. The obtained wheat germ milk had poor stability and flocculent stratification occurred after being left to stand at 4° C. for 12 hours.

[0151] In the comparative example 6, medium-temperature amylase was used for enzymatic hydrolysis at 65°C during the early refining process, and the flavor was poor. The reason was mainly because the lipase in the fresh wheat germ was not completely inactivated, resulting in oxidation reaction of the wheat germ during the production process, and the taste of fat oxidation was serious.

[0152] Comparative Example 7 used alkaline protease during the enzymatic hydrolysis process, resulting in a very prominent bitter taste of the whole wheat germ milk, and the tasters reported that the flavor was poor.

[0153] The above detailed description of the present invention is intended to enable those skilled in the art to understand the contents of the present invention and implement them, but it does not limit the protection scope of the present invention. The present invention is not limited to the above embodiments, and any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing whole wheat germ milk, characterized in that: The preparation method comprises the following steps: (1) mixing wheat germ, high temperature α-amylase and water, and grinding at 85-95° C.; (2) cooling the liquid of step (1) to 55-60° C., adding medium-temperature α-amylase, glucoamylase and protease for enzymolysis at 55-60° C.; (3) raising the temperature of the enzymatically hydrolyzed liquid to 85-95° C. and keeping the temperature at 85-95° C. for 10-15 minutes; (4) cooling the liquid of step (3) to 60-70° C. and homogenizing at 60-70° C.; (5) subjecting the homogenized liquid to high-pressure microfluidization treatment at 1000-1500 bar at 60-70° C.; (6) The slurry after high-pressure microfluidization treatment is mixed with dipotassium hydrogen phosphate and microcrystalline cellulose, and the whole wheat germ milk is obtained by shearing, homogenizing and high-temperature sterilization.

2. The method for preparing whole wheat germ milk according to claim 1, characterized in that: In the step (1), the mass ratio of the wheat germ to water is 1:(3.5-6), and the mass of the high-temperature α-amylase is 0.5%-1.5% of the mass of the wheat germ.

3. The method for preparing whole wheat germ milk according to claim 1, characterized in that: In the step (1), the D90 of the slurry after refining is 450-550 μm; and / or the refining time is 20-50 min.

4. The method for preparing whole wheat germ milk according to claim 1, characterized in that: The protease in step (2) is one or more of neutral protease, chymosin, aminopeptidase and glutaminase.

5. The method for preparing whole wheat germ milk according to claim 4, characterized in that: The high-temperature α-amylase activity is 104400-127600 U / g, the medium-temperature α-amylase activity is 11700-14300 U / g, the glucoamylase activity is 5850-7150 U / g, the neutral protease activity is 72000-88000 U / g, the chymosin activity is 67500-82500 U / g, the aminopeptidase activity is 450-550 U / g, and the glutaminase activity is 450-550 U / g.

6. The method for preparing whole wheat germ milk according to claim 1, characterized in that: The mass of the medium-temperature α-amylase in step (2) is 0.5% to 1.5% of the mass of the wheat germ in step (1), the mass of the glucoamylase in step (2) is 0.4% to 0.6% of the mass of the wheat germ in step (1), the mass of the protease in step (2) is 0.5% to 1.5% of the mass of the wheat germ in step (1); and / or the enzymolysis time in step (2) is 1.5 to 3 hours.

7. The method for preparing whole wheat germ milk according to claim 1, characterized in that: The amount of dipotassium hydrogen phosphate used in step (6) is 0.1%-0.3% of the total mass of the whole wheat germ milk; and / or the amount of microcrystalline cellulose used in step (6) is 0.1%-0.2% of the total mass of the whole wheat germ milk.

8. The method for preparing whole wheat germ milk according to claim 1, characterized in that: The temperature of the high temperature sterilization in step (6) is 85°C to 90°C and the time is 10 to 15 minutes.

9. The method for preparing whole wheat germ milk according to claim 1, characterized in that: The D90 of the slurry after homogenization in step (3) is 190-250 μm; the D90 of the slurry after high-pressure microfluidization treatment is 50-80 μm; the D90 of the slurry after homogenization in step (6) is 50-80 μm; and / or, the pressures of homogenization in step (4) and in step (6) are 250-300 bar, respectively.

10. The method for preparing whole wheat germ milk according to claim 1, characterized in that: The wheat germ is fresh wheat germ.

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