Milk Powder Making Machine Produces High Quality Milk Powder

  • The traditional milk powder production process begins with raw milk received from a Milk Processing Plant, pasteurized with a centrifugal cream separator and separated into skim milk and cream. If WMP is to be made, a portion of the cream is added back to skim milk to produce milk with a standardized fat content (usually 26-30% fat in the powder). Excess cream is used to make butter or anhydrous milk fat.
    The next step in the process is "preheating", during which the standard milk is heated to a temperature between 75 °C and 120 °C. Milk is kept at this condition for a specified period of time, ranging from a few seconds to a few minutes (pasteurization: 72 ° C for 15 s). Preheating causes controlled denaturation of whey protein in milk, which destroys bacteria, inactivates enzymes, produces natural antioxidants, and imparts thermal stability. The exact heating/holding method depends on the type of product and its intended end use. High preheating in WMP is associated with increased shelf life, but reduces solubility. Preheating can be indirect (through a heat exchanger), it can be direct (by steam injection or injection into the product), or a mixture of the two. Indirect heaters typically use waste heat from other parts of the process to reduce energy costs.
    In the evaporator, the preheated milk is concentrated or "concentrated" in stages. The total solids content of skimmed milk is about 9.0%, the whole milk is 13%, and the total solids is as high as 45 - 52%. This is accomplished by boiling the milk in a falling film inside the vertical tube under a vacuum below 72 ° C and removing the water in the form of steam. This steam can be mechanically or thermally compressed and then used to heat the milk in the next action of the evaporator, which can be operated at a lower pressure and temperature than the previous one. Modern factories may have seven effects in order to maximize energy efficiency. More than 85% of the water in the milk can be removed in the evaporator. The evaporator is very noisy because a large amount of water vapor flows at very high speeds inside the pipe.
    Spray drying
    Spray drying involves atomizing concentrated milk from an evaporator into fine droplets. This is done in a large drying chamber with a rotating disc atomizer or a series of high pressure nozzles in a stream of hot air (up to 200 ° C). The milk droplets are cooled by evaporation and they never reach the temperature of the air. The concentrate can be heated prior to atomization to reduce its viscosity and increase the energy available for drying. Most of the remaining water evaporates in the drying chamber, leaving a fine powder having an average particle size of typically less than about 0.1 mm diameter of about 6% water. The final or "secondary" drying takes place in a fluidized bed or a series of such beds in which hot air is blown through a layer of fluidized powder to remove moisture and have a moisture content of 2 - 4%.
    Packaging and storage
    Milk powder is much more stable than fresh milk, but in order to maintain the quality and shelf life of the milk powder, it is necessary to protect the milk powder from moisture, oxygen, light and heat. Milk powder easily absorbs moisture from the air, causing rapid deterioration in quality, agglomeration or agglomeration. Choose Jimei Food Machinery's Milk Powder Making Machine to produce high quality milk powder.