Cereal Chem 69:456-460   |  VIEW ARTICLE

Structure of Corn Starch Paste and Granule Remnants Revealed by Low-Temperature Scanning Electron Microscopy after Cryopreparation.

J. E. Fannon and J. N. Bemiller. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

To determine any correlation between the ultrastructure of corn starch pastes and the functional properties on which their applications are based, starch pastes and granule remnants were plunge-frozen in melting nitrogen and examined by low-temperature scanning electron microscopy. In all cases, pastes were composed of a continuous phase of bundles of molecules surrounding a discontinuous phase of swollen granule remnants commonly referred to as ghosts. Differences between starches were seen in the amount and size of the continuous phase and in the strength and appearance of the ghosts. Because ghost structure is important to starch paste properties, isolated ghosts were also examined to determine a relationship between ghost structures and functional properties of starches. The ghosts, like the pastes, showed structural differences that correlated strongly with the rheological behavior of each starch type. Low-temperature scanning electron microscopy should be useful as a rapid method for screening starch hybrids with unknown properties because the ultrastructures observed, although they may be somewhat artifactual, correlated with the functional properties of the starch.