Milk homogenization is a mechanical process that prevents cream from separating from milk. This is achieved by forcing hot milk under high pressure through a small space, breaking down the fat globules into much smaller sizes.
Here's a breakdown of the homogenization process:
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Heating: Milk is typically heated before homogenization to approximately 55-80°C (131-176°F). This ensures the milk fat is in a liquid state, making it easier to break down.
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High-Pressure Pumping: The heated milk is then pumped at high pressure, typically ranging from 10 to 25 MPa (1450 to 3625 psi), through a homogenizer.
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Orifice Passage: The homogenizer contains a small space or valve. As the milk passes through this restricted opening under high pressure, the large fat globules are subjected to intense shear forces.
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Fat Globule Disruption: These shear forces cause the large fat globules to break down into thousands of much smaller globules.
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Stabilization: The increased surface area of the newly formed, smaller fat globules is then coated with proteins (mainly caseins) and other molecules from the milk serum. This protein layer helps to stabilize the globules and prevent them from re-coalescing.
Key Effects of Homogenization:
- Reduced Creaming: Smaller fat globules remain dispersed throughout the milk, preventing the formation of a distinct cream layer.
- Improved Texture: Homogenized milk has a smoother and creamier texture.
- Enhanced Flavor: Homogenization can make the milk taste richer and fuller due to the more uniform distribution of fat.
- Whiter Appearance: The smaller fat globules scatter light more effectively, giving the milk a whiter appearance.
In summary, milk homogenization is a critical step in milk processing that improves stability, texture, and flavor by mechanically reducing the size of fat globules through high-pressure passage and subsequent stabilization.
