Homogenization of milk and the properties of homogenized milk

Milk is composed of water soluble material, colloidal material, and particles in suspension. The milk fat is suspended in milk as globules, which are microscopic in size and are distributed in the milk. On standing, most of these fat globules naturally rise and collect in the upper portion called the cream layer, leaving the lower portion called the skimmilk. Often, this separation of the cream from the skimmilk is not desirable.

A mechanical process has been developed to break up the globules so that they don't rise and form a cream layer. This milk is then sailed homogenized milk, and the process of breaking up the globules is called homogenization.

The homogenized milk was found to have many advantages over the unprocessed milk. The color was uniform, and no mixing was necessary in order to get the fat with the skimmilk. Some consumers believe that the flavor is richer. A softer curd is formed by coagulation that makes it easier to digest. Some disadvantages of homogenized milk are that undesirable flavors may develop in the product, processing costs are high, and sediment often occurs in the bottle of homogenized milk. The utilization of unsold homogenized milk presents a problem, as it is difficult to separate the fat from the homogenized milk.

Many factors in processing of milk have been studied in this problem. The effects of homogenizing at various pressures and temperatures were determined, Studies of homogenized milk indicate that there are changes in the curd tension, pH, acidity, viscosity, color, and bacteria count. A comparison of the feeding values and digestibility of homogenIzed milk and unhomogenized milk was made.

[From the Objects of Investigation, leaf 34]

1. To compare the procedure as to cost, efficiency, and adaptations.

2. To study some of the effects (physical, chemical, and bacteriological) of various procedures on the milk.

3. To compare the palatability of homogenized, normal soft-curd, and normal hard-curd milk.

4. To determine the feeding value of homogenized milk as compared to normal soft and hard-curd milks.

5. To compare the speed and ease of digestion of homogenized, soft-curd, and hard-curd milks.