Homogenization is a process of attaining homogeneous emulsions. This is achieved by passing the milk under high pressure through a small orifice; the shearing effect reduces the average diameter of the milk fat globules to less than 2 Am. As a result, the globules are less inclined to coalesce to large units and do not rise to form a cream line.
Homogenization is an important processing step for improving consistency and viscosity of yogurt due to incorporation of the finely divided fat globules within the coagulum structure. Further, coagulum stability also improves due to adsorption of casein micelle onto fat globules. The increased number of small fat globules tend to enhance the ability of the milk to reflect light, and as a result the fermented milk appears whiter. Use of unhomogenized milk leads to fat accumulation on top of the packaged product, which is disliked by most customers except in products where a cream line is specifically required (e.g., crusty yogurt in Greece).
Milk processing for fermented milk manufacture typically employs homogenization pressure in the range of 10-20 MPa at 50-70 °C temperature. Homogenization preceding heat processing is preferable to avoid risk of contamination after heat processing.
Was this article helpful?