Freeze‐dried Carbohydrate Containing Oil‐in‐water Emulsions: Microstructure and Fat Distribution

The structural relationships of fat and carbohydrate in the freeze‐dried matrix of oil‐in‐water model emulsions were investigated by using a variety of microscopic techniques (optical microscopy, scanning electron microscopy, and electron microprobe analysis) and solvent extraction methods. The separation of the lipid phase into surface and encapsulated fractions was quantitatively evaluated and the significance of this lipid distribution evaluated with respect to chemical stability of the dried emulsion. The degree of lipid encapsulation in the carbohydrate matrix is shown to depend on a number of process variables, including carbohydrate concentration and morphological characteristics, lipid concentration and freezing rate.