Homogenization of milk - a mechanical processing of milk (cream), which is grinding (dispersing) the fat globules by acting on the milk of significant external forces [Bredikhin, 2003; Krus, 2006]. Dispersion of fat globules, ie, size reduction and uniform distribution in the milk, the milk is achieved at a significant influence of an external force (pressure, ultrasound, high frequency and other electrical processing.) in special machines - homogenizers.
It is known that the storage of fresh milk and cream because of the difference in the density of the milk fat and plasma occurs ascent fat fraction or settling. The rate of sedimentation of fat depends on the size of fat globules, the viscosity of the fat globules connectivity with each other. Dimensions fat globules range widely from 0.5 to 0.18 microns. According to Stokes' formula, the rate of release (ascent) fat globules is directly proportional to the square of its radius. During the homogenization of milk sizes of the fat globules are reduced approximately 10-fold, and the ascent rate becomes approximately 100 times less. During crushing the ball fat redistributed its sheath material. In the construction of shells formed small balls mobilized plasma proteins, phosphatides and part passes from the fat globules in milk plasma. This process helps to stabilize the fat emulsion was finely homogenized milk. Therefore, when a high dispersion of milk fat globules almost no advocates. The mechanism of splitting the fat globules is shown in Fig.
de d - diameter of the hole in the valve seat, V o - speed milk valve, V' o - velocity in the boundary section, p o - pressure valve, V 1 - speed of movement of the valve gap, p 1 - the pressure in the valve slit , h-height of the valve gap.
Figure - Scheme crushing fat balls in the valve gap homogenizer
Homogenization feedstock, i.e. homogenizing the milk , it promotes the manufacture of dairy products (cream, kefir, yogurt, etc.) - increasing the strength and improving the consistency of protein clots prevent the formation of adipose plugs on the product surface [Bredikhin, 2003].
The main unit of modern homogenizing valve type is the homogenizing head. It can be a one-stage or two-stage. Two-stage homogenization with a large pressure drop in both stages vysokozhirnyh used in the manufacture of dairy products (cream, ice cream mix, and the like). It allows you to dissipate (break) form clusters of fat globules. For the production of other types of dairy products including liquid milk, you can use a single-stage homogenization of milk .