Molecular organization in lipids and emulsions.

Important knowledge on the lipid structure in emulsions is based on studies of simple systems containing only a few components, such as a ternary system consisting of a polar lipid, a triglyceride oil, and water. Structures and phase equilibria in such model system provide information on emulsionstabilizing mechanisms which can be translated into the behavior of complex food emulsions. The structures in the different states of order of lipid and lipid–water phases will be summarized with special regard to emulsions. Additional information on the chemistry and physics of emulsions are found in Ref. (1). Lipids are unique in their ability to form a wide variety of structures, ranging from micellar solutions to liquid-crystalline phases and different crystalline forms (polymorphism). An important factor behind the molecular organizations they exhibit is the amphiphilic character of the molecule— the possibility to orient hydrophilic groups toward polar regions, such as water, and hydrophobic groups separated into nonpolar regions.