Retrogradation of starch and the role of its components

The retrogradation of starch is not a simple process: it manifests itself in apparently different processes, such as increased firmness and recrystallization of gelatinized starch gels with time. The components of starch, amylopectin and amylose, have different roles in retrogradation. Much evidence suggests that changes in the amylopectin are the main cause for what we call retrogradation because they are responsible for all long-term rheological and structural changes. The amylose, however, is responsible for the short-term changes. The water content and storage temperature greatly affect the rate and extent of retrogradation of starch gels. Other compounds added to the starch, such as lipids and surfactants, can retard or interfere with the retrogradation. In this paper, some suggestions concerning the effects of each component in the starch are discussed. Starches from different botanical sources, despite similar amylose/amylopectin ratios, can retrograde to different extents, indicating that the structure of the amylopectin seems to be a very important factor in retrogradation.