Influence of Emulsion Interfacial Membrane Characteristics on Ostwald Ripening in a Model Emulsion

Ostwald ripening is a major destabilization mechanism for emulsions containing flavor oils with relatively high water solubilities. Emulsions with different oil phase compositions were prepared that were stabilized by polyoxyethylene alkyl ether-type emulsifiers with differently sized hydrophilic and hydrophobic groups. Emulsions prepared using only orange oil were highly unstable to Ostwlad ripening during storage. When emulsifier concentration was increased, Ostawald ripening in emulsions containing emulsifiers with small hydrophilic groups was inhibited, while size increment of droplets in emulsions containing emulsifiers with large hydrophilic groups was not. Droplet enlargement was effectively inhibited by incorporating corn oil into the oil phase prior to homogenization. However, the concentration of corn oil required to inhibit Ostwald ripening varied depending on the structural characteristics and concentrations of the emulsifiers present. These results could have important implications for the selection of emulsifiers to improve the physical stability of orange oil emulsions for use in the food and beverage industries.