A method for avoiding loss of vitamin k2 in a dairy product production process and use thereof

Abstract

The application provides a method for avoiding loss of vitamin K2 in a dairy product production process and application thereof. The method comprises the following steps: adding vitamin K2 into a material liquid which is subjected to mixing, homogenization and cooling to below 10 DEG C; and the application further provides a preparation method of milk powder with added vitamin K2. The above method can greatly reduce the loss rate of VK2 in the final product, while ensuring good mixing uniformity of VK2.

Description

Technical Field

[0001] This invention belongs to the field of dairy processing, specifically relating to a method for avoiding vitamin K2 loss during dairy production, a milk powder with added vitamin K2, and its preparation method. Background Technology

[0002] Vitamin K2 (VK2) promotes the absorption and utilization of calcium in the body, thereby improving bone quality. From a molecular structure perspective, VK2 is the most unstable of the vitamin K compounds, exhibiting significant fluctuations and resulting in a high rate of product defects. This greatly limits its application in the production of formulated milk powder. VK2 has the following structure:

[0003] Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method for avoiding vitamin K2 loss during dairy product production, as well as a method for preparing vitamin K2-added milk powder. This method significantly reduces the loss rate of VK2 in the final product while ensuring good mixing uniformity of VK2.

[0005] There are two methods for adding Vitamin K2 to infant formula: dry addition and wet addition. Dry addition of Vitamin K2 has a high dispersion coefficient (62.16%) due to the low content of Vitamin K2 in infant formula, deviating significantly from the target value. Given the limitations of dry addition, the current practice in the infant formula industry is primarily wet addition. This involves injecting a multivitamin packet containing Vitamin K2 into a wet mixing tank during pretreatment, followed by rapid mixing and circulation in both the wet and vacuum high-speed mixing tanks. From mixing to powder output, the process involves pretreatment, concentration, and drying. This conventional production method results in significant Vitamin K2 loss. Currently, there are no records of fluctuations in Vitamin K2 content when used in formulated milk powder. The inventors of this invention discovered that the main factors causing large fluctuations in VK2 during the production process include light, oxygen, microorganisms, pH, and metal ions. To further investigate the causes of VK2 loss, the inventors studied the entire milk powder production line in the factory, including: raw milk storage time, pasteurized milk storage time, mixing temperature in the pretreatment stage, order of nutrient addition, VK2 dissolution time, vacuum mixing speed, time interval between VK2 and mineral addition, and temporary storage time from the end of mixing to the start of concentration; flash evaporation temperature, bulk evaporation temperature, sterilization temperature, sterilization time, concentration temperature, concentration time, and temporary storage time of concentrated milk in the concentration stage; and preheating temperature, air inlet temperature, air outlet temperature, and powder spraying time in the drying stage. These process points were studied, and experiments were conducted on the main influencing factors. The collected results were analyzed using a univariate regression model, and it was found that the above factors were not significantly correlated with the fluctuation of VK2 in the product. The inventors further investigated the vacuum mixing time of the liquid after adding VK2 in the pretreatment stage (i.e., "VK2 mixing time") and found that the correlation coefficient R-Sq between the VK2 result and the VK2 mixing time was 83.3%, showing a strong negative correlation.

[0006] The inventors analyzed the situation as follows: Given the characteristics of VK2, it is an oil-soluble vitamin and lacks fat protection in milk. When compound minerals and compound vitamins (including VK2) are added in a concentrated manner during the mixing process, the local high concentration of active nutrients in the high-speed mixing environment at around 55°C will decompose the VK2 molecules in a short time, resulting in losses.

[0007] To address the above issues, the inventors continuously researched and verified the methods and parameters for adding VK2 to the feed solution. Ultimately, they developed a production method that involves adding VK2, where VK2 is not added during the mixing process along with other nutrients, but rather after the feed solution has been mixed, homogenized, cooled to below 10°C, and pumped into a temporary storage tank.

[0008] Based on the above research, the present invention provides a method for avoiding vitamin K2 loss during dairy product production, which includes: adding vitamin K2 to a feed solution that has been mixed, homogenized, and cooled to below 10°C.

[0009] According to a specific embodiment of the present invention, vitamin K2 is preferably added to the mixture that has been mixed, homogenized and cooled to below 8°C.

[0010] According to a specific embodiment of the present invention, preferably, the liquid is prepared from dairy raw materials other than vitamin K2 by mixing, homogenizing and cooling; or, the liquid is prepared from dairy raw materials containing vitamin K2 (this portion of vitamin K2 can be a part of the vitamin K2 that needs to be added to the dairy product, and the remaining portion of vitamin K2 is added to the liquid after mixing, homogenizing and cooling to below 10°C) by mixing, homogenizing and cooling.

[0011] According to a specific embodiment of the present invention, preferably, the addition of vitamin K2 to the mixed, homogenized, and cooled liquid to below 10°C is carried out in a temporary storage tank.

[0012] According to a specific embodiment of the present invention, preferably, the raw materials of the dairy product contain minerals.

[0013] According to a specific embodiment of the present invention, preferably, the mineral includes one or a combination of two or more of ferrous sulfate, zinc sulfate and calcium carbonate.

[0014] According to a specific embodiment of the present invention, preferably, after the vitamin K2 is added to the liquid, it is stirred at a speed of 200-900 r / min for a time of 20-110 min.

[0015] According to a specific embodiment of the present invention, preferably, the stirring is carried out in a temporary storage tank.

[0016] According to a specific embodiment of the present invention, preferably, the dairy product includes one of liquid milk, yogurt, milk powder, and cheese.

[0017] According to a specific embodiment of the present invention, VK2 is dissolved separately and then pumped into a temporary storage tank, and then mixed with milk in a relatively gentle stirring manner. This can eliminate the influence of local high concentration of metal ions on VK2 during high-speed mixing, and at the same time shorten the total contact time between VK2 and the liquid. This greatly reduces the loss rate of VK2 in the final product and ensures the quality of the product.

[0018] This invention also provides a method for preparing milk powder with added vitamin K2, which includes the following steps:

[0019] Vitamin K2 is added to the mixture after it has been mixed, homogenized, and cooled to below 10°C.

[0020] According to a specific embodiment of the present invention, preferably, in the above preparation method, vitamin K2 is added to the liquid mixture that has been mixed, homogenized, and cooled to below 8°C.

[0021] According to a specific embodiment of the present invention, preferably, in the above preparation method, after the vitamin K2 is added to the liquid, it is stirred, and the stirring speed is 200-900 r / min, and the stirring time is 20-110 min.

[0022] According to a specific embodiment of the present invention, preferably, in the above preparation method, the feed solution contains minerals, and the minerals preferably contain one or more of ferrous sulfate, zinc sulfate and calcium carbonate.

[0023] According to a specific embodiment of the present invention, preferably, the above preparation method includes the following steps:

[0024] (1) Mix raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids at a mixing temperature of 40-60℃ and a mixing time of 20-60 min to obtain a mixed liquid.

[0025] In the process of mixing, one or more of the following are added to the mixture liquid: compound vitamins or their aqueous dispersions, compound minerals or their aqueous dispersions. The compound vitamins include one or more of the following: vitamin A, vitamin D, vitamin E, vitamin C, vitamin B1, folic acid, pantothenic acid, niacin, and lutein.

[0026] (2) After preheating the above mixture to 45-70°C, homogenize it with a first-stage homogenization pressure of 70-150 bar and a second-stage homogenization pressure of 20-50 bar to obtain a homogenized mixture.

[0027] (3) Cool the above homogenized liquid to below 10°C to obtain a cooled liquid;

[0028] (4) After dispersing vitamin K2 in water, add it to the above-mentioned cooled liquid and stir at 200-900 r / min for 20-110 min to obtain a liquid containing vitamin K2;

[0029] (5) After sterilization, concentration and spray drying, the vitamin K2-added milk powder is obtained.

[0030] According to a specific embodiment of the present invention, preferably, in step (1), when the mineral contains calcium carbonate, calcium carbonate or its aqueous dispersion is added separately.

[0031] According to a specific embodiment of the present invention, preferably, in step (3), the cooling temperature is 0-8°C.

[0032] According to a specific embodiment of the present invention, preferably, step (4) is performed in a temporary storage tank.

[0033] According to a specific embodiment of the present invention, preferably, in step (4), the stirring speed is 400-700 r / min and the stirring time is 30-80 min.

[0034] According to a specific embodiment of the present invention, the above preparation method specifically includes the following steps:

[0035] (1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 45-55℃ and the mixing time is 30-50min.

[0036] (2) During the mixing process, calcium carbonate is added to water and stirred and dispersed for 15-25 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins are added to water and stirred and dispersed for 4-10 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals are added to water and stirred and dispersed for 10-30 minutes and then pumped into the mixing tank to mix with the liquid.

[0037] (3) After the mixed liquid is preheated to 55-65℃, it is homogenized at a first-stage homogenization pressure of 90-120 bar and a second-stage homogenization pressure of 25-35 bar.

[0038] (4) Quickly cool the homogenized liquid to 0-8℃ and pump it into a temporary storage tank;

[0039] (5) After dispersing VK2 separately with water in the nutrient container for 4-10 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 400-700 r / min for 30-80 minutes.

[0040] (6) Pasteurize the liquid material at a temperature of 88-97℃ for 10-30 seconds.

[0041] (7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃;

[0042] (8) The concentrated liquid is spray-dried with an inlet air temperature of 180-220℃ and an outlet air temperature of 75-95℃. Then it is cooled to below 30℃ through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0043] The present invention also provides a vitamin K2-fortified milk powder prepared by the above preparation method.

[0044] The method for avoiding vitamin K2 loss during dairy product production, as well as the method for preparing vitamin K2-added milk powder, provided by this invention, can greatly reduce the loss rate of VK2 in the final product while ensuring good mixing uniformity of VK2. Attached Figure Description

[0045] Figure 1 The correlation curve between VK2 results (VK2 content detection results of the final product) and storage time of pasteurized milk is shown.

[0046] Figure 2 The correlation curve between the VK2 result (the final product VK2 content detection result) and the time interval between VK2 and mineral addition is shown.

[0047] Figure 3 The correlation curve between the VK2 result (the final product VK2 content detection result) and the temporary storage time from the end of mixing to the start of concentration is shown.

[0048] Figure 4 The correlation curve between VK2 results (VK2 content detection results of the final product) and the evaporation temperature of the effective body is shown.

[0049] Figure 5 The correlation curve between the VK2 result (the VK2 content detection result of the final product) and the flash evaporation temperature is shown.

[0050] Figure 6 The correlation curve between the VK2 result (the VK2 content detection result of the final product) and the lower flash temperature is shown.

[0051] Figure 7 The correlation curve between VK2 results (VK2 content detection results of the final product) and concentration time is shown.

[0052] Figure 8 The correlation curve between VK2 results (VK2 content detection results of the final product) and spraying time is shown.

[0053] Figure 9 The correlation curve between the VK2 result (the final product VK2 content detection result) and the VK2 mixing time is shown. Detailed Implementation

[0054] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0055] The VK2 is provided by Beijing Jinkangpu Food Technology Co., Ltd., with a VK2 content of 2050μg / g and a package weight of 0.33kg; theoretically, it provides 67.65μg / 100g of VK2 for the final product.

[0056] The inventors studied the process parameters and investigated the main influencing factors of VK2 fluctuations (pasteurized milk storage time, time interval between VK2 and mineral addition, temporary storage time from the end of mixing to the start of concentration, bulk evaporation temperature, upper flash temperature, lower flash temperature, concentration time, spray drying time, and vacuum mixing time of the liquid after adding VK2 (i.e., "VK2 mixing time" below). They monitored the production process parameters of one batch of VK2-added modified milk powder daily for at least 10 days. They focused on recording independent variable data such as pasteurized milk storage time, time interval between VK2 and mineral addition, temporary storage time from the end of mixing to the start of concentration, bulk evaporation temperature, upper flash temperature, lower flash temperature, concentration time, and spray drying time, and also recorded the VK2 content detection results in the final product (dependent variable). The collected results were analyzed using a univariate regression model, with the dependent variable and each independent variable analyzed separately. The results are as follows: Figures 1-9 As shown, the results indicate that there is no significant correlation between the storage time of pasteurized milk, the time interval between the addition of VK2 and minerals, the temporary storage time from the end of mixing to the start of concentration, the evaporation temperature, the upper flash temperature, the lower flash temperature, the concentration time, the spraying time, and the fluctuation of VK2 content in the product (the final product VK2 content detection result) (the correlation coefficients R-Sq are all below 80%). However, the regression equation correlation coefficient R-Sq between VK2 result and VK2 mixing time is 83.3%, showing a strong negative correlation, that is, VK2 mixing time is the main factor causing VK2 loss.

[0057] Comparative Example 1

[0058] This comparative example provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0059] Formula: 4000kg raw milk, 375kg demineralized whey powder, 30kg whey protein powder, 85kg galactooligosaccharides, 2kg phospholipids, 2.5kg compound vitamins (including vitamin A, vitamin D, vitamin E, vitamin C, vitamin B1, folic acid, pantothenic acid, niacin, and lutein), 1kg compound minerals (including ferrous sulfate and zinc sulfate), 0.33kg vitamin K2, and 15kg calcium carbonate.

[0060] The preparation method is as follows:

[0061] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0062] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid. Compound vitamins and VK2 were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid. Compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0063] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0064] 4) Quickly cool the homogenized liquid to 6°C and transfer it to a temporary storage tank;

[0065] 5) Stir in the temporary storage tank at a speed of 550 r / min for 60 min;

[0066] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0067] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 47%.

[0068] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0069] Comparative Example 2

[0070] This comparative example provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0071] Formula: Same as Comparative Example 1;

[0072] The preparation method is as follows:

[0073] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0074] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0075] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0076] 4) Quickly cool the homogenized liquid to 10°C and transfer it to a temporary storage tank;

[0077] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 550 r / min for 60 minutes.

[0078] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0079] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 48%.

[0080] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0081] Comparative Example 3

[0082] This comparative example provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0083] Formula: Same as Comparative Example 1;

[0084] The preparation method is as follows:

[0085] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0086] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0087] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0088] 4) Quickly cool the homogenized liquid to 6°C and transfer it to a temporary storage tank;

[0089] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 150 r / min for 60 minutes.

[0090] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0091] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 49%.

[0092] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0093] Comparative Example 4

[0094] This comparative example provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0095] Formula: Same as Comparative Example 1;

[0096] The preparation method is as follows:

[0097] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0098] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0099] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0100] 4) Quickly cool the homogenized liquid to 6°C and transfer it to a temporary storage tank;

[0101] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 1000 r / min for 60 minutes.

[0102] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0103] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 47%.

[0104] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0105] Comparative Example 5

[0106] This comparative example provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0107] Formula: Same as Comparative Example 1;

[0108] The preparation method is as follows:

[0109] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0110] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0111] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0112] 4) Quickly cool the homogenized liquid to 6°C and transfer it to a temporary storage tank;

[0113] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 550 r / min for 15 minutes.

[0114] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0115] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 49%.

[0116] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0117] Comparative Example 6

[0118] This comparative example provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0119] Formula: Same as Comparative Example 1;

[0120] The preparation method is as follows:

[0121] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0122] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0123] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0124] 4) Quickly cool the homogenized liquid to 6°C and transfer it to a temporary storage tank;

[0125] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 550 r / min for 120 minutes.

[0126] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0127] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 46%.

[0128] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0129] Example 1

[0130] This embodiment provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0131] Formula: Same as Comparative Example 1;

[0132] The preparation method is as follows:

[0133] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0134] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0135] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0136] 4) Quickly cool the homogenized liquid to 8°C and transfer it to a temporary storage tank;

[0137] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 200 r / min for 20 minutes.

[0138] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0139] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 47%.

[0140] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0141] Example 2

[0142] This embodiment provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0143] Formula: Same as Comparative Example 1;

[0144] The preparation method is as follows:

[0145] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0146] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0147] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0148] 4) Quickly cool the homogenized liquid to 6°C and transfer it to a temporary storage tank;

[0149] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 900 r / min for 20 minutes.

[0150] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0151] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 48%.

[0152] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0153] Example 3

[0154] This embodiment provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0155] Formula: Same as Comparative Example 1;

[0156] The preparation method is as follows:

[0157] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0158] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0159] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0160] 4) Quickly cool the homogenized liquid to 4°C and transfer it to a temporary storage tank;

[0161] 5) Dissolve VK2 separately in water in the nutrient container and stir for 5 minutes, then transfer it to the temporary storage container and stir at 200 r / min for 110 minutes.

[0162] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0163] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 47%.

[0164] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0165] Example 4

[0166] This embodiment provides a modified milk powder with added VK2, the formulation and preparation method of which are as follows:

[0167] Formula: Same as Comparative Example 1;

[0168] The preparation method is as follows:

[0169] 1) Put raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids into a vacuum mixing tank and mix them at high speed. The mixing temperature is 50℃ and the mixing time is 40min.

[0170] 2) During the mixing process, calcium carbonate was added to water and stirred and dispersed for 20 minutes in the nutrient tank and then pumped into the mixing tank to mix with the liquid; compound vitamins were added to water and stirred and dispersed for 7 minutes and then pumped into the mixing tank to mix with the liquid; compound minerals were added to water and stirred and dispersed for 15 minutes and then pumped into the mixing tank to mix with the liquid.

[0171] 3) After the mixed liquid is preheated to 60°C, it is homogenized at a first-stage homogenization pressure of 110 bar and a second-stage homogenization pressure of 40 bar.

[0172] 4) Quickly cool the homogenized liquid to 2°C and transfer it to a temporary storage tank;

[0173] 5) After dispersing VK2 separately with water in the nutrient container for 5 minutes, transfer it to the temporary storage container and stir it in the temporary storage container at a speed of 900 r / min for 110 minutes.

[0174] 6) Pasteurize the liquid at a temperature of 91℃ for 15 seconds.

[0175] 7) The sterilized liquid is concentrated at a concentration temperature of 50-65℃, and the dry matter content of the concentrated liquid is 46%.

[0176] 8) The concentrated liquid is spray-dried with an inlet air temperature of 190°C and an outlet air temperature of 88°C. Then it is cooled to below 30°C through a fluidized bed to obtain a uniform and consistent modified milk powder with added VK2.

[0177] Ten samples were randomly selected from the final products of each comparative example and embodiment. The vitamin K2 content (μg / 100g) was tested according to the vitamin K2 (fermentation method) detection method in Annex 3 of the Announcement on New Varieties of Food Additives such as Calcium Alginate (No. 8, 2016), and the average value and coefficient of variation were calculated. The larger the coefficient of variation, the worse the uniformity of VK2 mixing. Then, the loss rate of VK2 was calculated based on the theoretical value of 67.65 μg / 100g. The formula for calculating the loss rate is: VK2 loss rate = (67.65 μg / 100g - average value of VK2 test results) / 67.65 μg / 100g × 100%. The test results are shown in Table 1 below:

[0178] Table 1 VK2 test results

[0179]

[0180]

[0181] The data above shows that Comparative Example 1 indicates the highest VK2 loss rate (39.39%) is caused by the conventional method of adding VK2 along with other nutrients to the liquid mixture. Adding VK2 after the liquid mixture has been mixed, homogenized, cooled, and transferred to a storage tank significantly reduces this loss rate, but there are limitations: Comparative Example 2 shows that when the liquid cooling temperature is above 8°C, the VK2 loss rate in the final product is also relatively high (21.51%); Comparative Example 3 shows that when the agitator speed in the storage tank is below 200 rpm, the uniformity of VK2 mixing deteriorates; Comparative Example 4 shows that when the agitator speed in the storage tank is above 900 rpm, the VK2 loss rate also increases to 26.39%; Comparative Example 5 shows that when the stirring time in the storage tank is below 20 min, the uniformity of VK2 mixing deteriorates; and Comparative Example 6 shows that when the stirring time in the storage tank is above 105 min, the VK2 loss rate increases again. Examples 1, 2, 3, 4, and 5 all demonstrate that adding VK2 after the liquid has been mixed, homogenized, cooled to below 10°C, and pumped into a temporary storage tank, and with the stirring speed of the temporary storage tank controlled at 200-900 r / min and the stirring time controlled between 20-105 min, will greatly reduce the loss rate of VK2 in the final product, while the uniformity of VK2 mixing is also acceptable.

Claims

1. A method for preparing milk powder with added vitamin K2, comprising the following steps: (1) Mix raw milk, demineralized whey powder, whey protein powder, galactooligosaccharides and phospholipids at a mixing temperature of 40-60℃ and a mixing time of 20-60 min to obtain a mixed liquid. In the process of mixing, one or more of the following are added to the mixture liquid: compound vitamins or their aqueous dispersions, compound minerals or their aqueous dispersions. The compound vitamins include one or more of the following: vitamin A, vitamin D, vitamin E, vitamin C, vitamin B1, folic acid, pantothenic acid, niacin, and lutein. (2) After preheating the above mixture to 45-70°C, homogenize it with a first-stage homogenization pressure of 70-150 bar and a second-stage homogenization pressure of 20-50 bar to obtain a homogenized liquid. (3) Cool the above homogenized liquid to below 8°C to obtain a cooled liquid; (4) After dispersing vitamin K2 in water, add it to the above-mentioned cooled liquid and stir and mix at a speed of 200-900 r / min for 20-110 min to obtain a liquid containing vitamin K2; (5) After sterilization, concentration and spray drying, the milk powder with added vitamin K2 is obtained.

2. The preparation method according to claim 1, wherein, The mineral comprises one or more of ferrous sulfate, zinc sulfate, and calcium carbonate.

3. The preparation method according to claim 1, wherein, Step (4) is performed in a temporary storage tank.

4. The preparation method according to claim 1, wherein, In step (4), the stirring speed is 400-700 r / min and the stirring time is 30-80 min.

5. A milk powder fortified with vitamin K2 prepared by any one of claims 1-4.

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