Cream processing

The creaming process, in which emulsion droplets rise or settle without significant coalescence, is not, by itself, emulsion breaking. Creaming produces two separate layers of emulsion that have different droplet concentrations and are usually distinguishable from each other by colour or opacity. Creaming does promote coa-... 

Increased demands on the keeping qualities of butter require careful construction, operation, and cleaning of the milk- and cream-processing equipment, as well as research to develop machines that will ensure butter production and packing under conditions without contamination and air admixture. It has been demonstrated that butter produced under closed conditions has a better keeping quality than butter produced in open systems (83). 

Sedimentation The settling of suspended particles or droplets due to gravity or an applied centrifugal field. Negative sedimentation, when droplets rise upwards, is also called flotation and is a part of the creaming process. 

The creaming process in the emulsions studied resulted in a distinct boundary between the water-rich and oil-rich... 

Initially, in a freshly prepared emulsion, the oil dro plets were homogeneously distributed in the entire sample volume. This situation was rapidly changed as a result of the creaming process. As the creaming process progressed, the conductivity in the lower part of flie emulsion increased because of the decreased volume fraction of oil in this region. At the same time the conductivity in the upper part declined. The difference in the measured conductivities was... 

In the practice of pharmacy preparations, it is usual to try to distribute the dispersed phase more finely with a rotor-stator mixer or a simple mechanical (paddle) mixer (pourable emulsions), or, for semisolid emulsions, with a mortar and pestle or a mixing device. Magnetic stirrers are unsuitable. Impaction of air should be avoided because the liberation of air bubbles can accelerate the creaming process (in case of pourable emulsions) and promote possible oxidation of the lipid base or of an active substance. A Stephan mixer with vacuum (see Sect. 28.6.1) is a suitable device for the preparation of emulsions without inclusion of air. 

Raising the viscosity of the continuous phase will slow the creaming process, as will reducing the droplet size or adjusting the density of the droplet to match closely the density of the external phase. Droplets may also retain their identity, but form multidroplet... 

Below we describe the use of the ultrasonic monitor to detect creaming in a polydisperse concentrated emulsion, and to characterise flocculation from the creaming behaviour. The effects of added polymers on the flocculation and creaming processes are also described. 

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