Controlling the molecular structure of food hydrocolloids

A process is described which enables the molecular structure of a wide range of food hydrocolloids to be modified in a controlled manner. It involves treating the hydrocolloid in the solid state with ionising radiation in the presence of a mediating gas. The molecular weight can be increased to the point where it ceases to be completely water soluble, and thereafter, with further dose increases, a hydrogel state results. The paper describes the changes which have been introduced into globular structures such as arabinogalactan proteins, branched chain polysaccharides such as pullulan and dextran, chemically modified structures such as carboxymethyl cellulose and gelling plysaccharides such as xanthan, pectin and carrageenan. Proteins can also be similarly modified and gelatin is used as an example. The change in physical properties and functionality, reflect the molecular changes, particularly emulsification, water binding, viscosity and viscoelasticity. Interactive blends can be produced when solid state mixtures of these materials are co-processed. (c) 2005 Elsevier Ltd. All rights reserved.