This method of mechanical treatment of milk and liquid dairy products increases the dispersion of the fat phase in them, which makes it possible to exclude the settling of fat during milk storage, the development of oxidative processes, destabilization, and churning during intensive mixing and transportation. In addition, homogenization of raw materials contributes to:
- Pasteurized milk and cream – the acquisition of uniformity (taste, color, fat content).
- Sterilized milk and cream – increased storage stability.
- Fermented milk products (sour cream, kefir, yogurt, etc.) – increase the strength and improve the consistency of protein clots and eliminate the formation of a fatty plug on the surface of the product.
- Condensed canned milk – to prevent the release of the fatty phase during long-term storage.
- Powdered whole milk – a decrease in the amount of free milk fat that is not protected by protein shells, which leads to its rapid oxidation under the action of atmospheric oxygen
- Reconstituted milk, cream, and fermented milk drinks – to create a full taste of the product and prevent the appearance of a watery aftertaste.
- Milk with fillers (cocoa etc.) – improve taste, increase viscosity and reduce the likelihood of sediment formation.
Dispersion of fat globules, i.e., reduction in their size and uniform distribution in milk, is achieved by exposing milk to a significant external force (pressure, ultrasound, high-frequency electrical processing, etc.) in special machines – homogenizers. The most widespread in the dairy industry is the homogenization of milk by forcing it through the annular valve slot of the homogenizing head of the machine. Fat globules are dispersed while passing through this gap. A pump generates the required pressure. In the production of whole milk, the size of fat globules decreases from 3-4 microns to 0.7-0.8 microns.
The central unit of modern valve-type homogenizers is homogenizing block. It can be one or two stages. The second stage usually operates at a lower pressure than the first. The use of one- or two-stage homogenization depends on the type of produced dairy products.
Two-stage homogenization with a significant pressure drop on both stages is used in producing high-fat dairy products (cream, ice cream mixtures, etc.). It allows you to disperse (break) the resulting accumulations of fat globules. However, one-stage homogenization can be used for the production of other types of dairy products, including drinking milk.
