Stabilizers

The phenomenon just described is the promotion of emulsion formation; this is not the same as stabilization of emulsions. The difference is seen by reference to Figure 2. After the emulsion is formed, if it is allowed to stand, the oil droplets will rise to the top or cream (assuming the volume ratio of oil to water is low enough for flotation to occur). The rate of creaming is inversely related to droplet diameter and to the viscosity of the aqueous phase: large droplets rise faster than small droplets, and faster in water than in a viscous gum solution. Emulsifiers that promote formation of smaller diameter drops and additives that increase viscosity give emulsions in which the rate of separation is slower, so in that sense only the emulsion is stabilized.

When two oil droplets make contact (facilitated by the creaming process), they may either clump (stick together, but retain their individual identity) or coalesce into one larger droplet, reducing total surface area and total excess interfacial energy. Clumped droplets may be readily redis-persed by simply stirring the system; inverting a bottle of creamed (nonhomogenized) milk a few times redistributes the clumped milkfat droplets. In coalescence the emulsifier

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