ABSTRACT
Many aspects of dispersed systems are important to an understanding of the properties of most foods and the manufacture of fabricated foods. A few are homogeneous solutions, such as cooking oil and some drinks, but even beer—as consumed—has a foam layer. The properties of a dispersed system cannot be fully derived from its chemical composition, since they also depend on physical structure. Most foods are dispersed systems, which affects properties as speed of chemical changes, flavor, visual appearance, consistency, and physical stability. Many food products contain mixtures of biopolymers, often mixtures of proteins and polysaccharides. In solution, the nature of the protein-polysaccharide interaction has a large effect on the properties of the mixed system. Demixing will be arrested if the continuous phase forms a gel before the system reaches equilibrium in a macroscopic phase separated two-layer system. Food technologists make gels for a purpose, often to obtain a certain consistency or to provide physical stability.
