Homogenizer Principle and Usage
1. Homogenizer Working Principle:
The precise fit between the rotor and stator, along with the claw-type structure of the working head (manufactured from rotor and stator forgings), allows for bidirectional material intake and high shearing efficiency.
The intermittent high-shear dispersion emulsifying homogenizer utilizes the high-speed, stable rotation of the rotor to generate high-frequency, intense circumferential tangential velocity and angular velocity, resulting in comprehensive kinetic energy efficiency.
Under the action of the stator, the narrow gap between the stator and rotor creates a strong, reciprocating combined effect of hydraulic shearing, friction, centrifugal extrusion, and liquid flow collision. The material circulates repeatedly within the container, undergoing the above processes to ultimately obtain the product.
2. Usage:
Application of Homogenizer in Soymilk: During homogenization, soymilk is extruded from the narrow slit of the homogenizing valve under high pressure. Fat globules, protein particles, and other components are refined under the combined action of shear force, impact force, and cavitation effect, forming a uniform dispersion. This prevents fat from floating and protein from settling, increases the gloss of the soymilk, and improves its stability.
The homogenization effect of soy milk is affected by three factors: homogenization pressure, homogenization temperature, and the number of homogenization cycles. Homogenization pressure is limited by the equipment. In soy milk production, a pressure of 20-30 MPa can be used for homogenization. The ideal temperature for homogenization is generally controlled between 55-65℃. The number of homogenization cycles is 1-2.
The homogenization process can be performed before or after sterilization. Both arrangements have advantages and disadvantages. If homogenization is performed before sterilization, the sterilization process can, to some extent, disrupt the homogenization effect, making the soy milk more prone to oil streaks. However, this process reduces the chance of contamination after sterilization, resulting in higher storage safety and relatively lower equipment costs. Furthermore, homogenized soy milk is less likely to form scale when entering the sterilizer. If homogenization is performed after sterilization, the above situation is reversed.
Application of homogenizers in raw milk: Under strong mechanical action (16.7-20.6 MPa), large fat globules in the milk are broken down into smaller fat globules, resulting in a uniform dispersion of fat globules throughout the milk. Homogenization effectively prevents fat globules from floating to the surface. In pasteurized milk production, the homogenizer is typically located in the first heat recovery stage of sterilization. In indirect-heating UHT milk production, the homogenizer is located before sterilization. In direct-heating UHT milk production, the homogenizer is located after sterilization.
Therefore, an aseptic homogenizer should be used. Homogenization not only prevents fat globules from floating to the surface but also offers other advantages: homogenized milk fat globules are smaller in diameter, making them easier for the body to digest and absorb. Homogenization softens milk protein curds, promoting digestion and absorption. In enzyme-based cheese production, homogenization accelerates milk coagulation, resulting in a more consistent flavor in the dairy product.
Preheating is required before homogenization, reaching 60-65°C. Homogenization typically employs a two-stage process: the first stage uses higher pressure (16.7-20.6 MPa) to break down fat globules, while the second stage uses lower pressure (3.4-4.9 MPa) to disperse the broken small fat globules and prevent adhesion.
Applications of homogenizers in citrus juice: After centrifugation, the pulp particles in citrus juice are already quite homogeneous. To further refine the particles, a homogenizer can be used after centrifugation at a pressure of 20-35 MPa.
Applications of homogenizers in peach pulp juice beverages: A homogenization pressure of 25-35 MPa is used. This enhances the affinity between pectin and juice, improves juice stability, reduces particle size and density differences, prevents stratification and sedimentation, and results in a uniform, viscous texture and a smooth mouthfeel.