Macrostructure of selected raw starches and selected heated starch dispersions

The similarities and differences between raw starches and heated starch-water dispersions were determined pictorially using a scanning electron microscope. The photomicrographs showed that raw unmodified starches ranged from small and round to large and ellipsoidal in shape, with variation in uniformity and smoothness of the surface. Heating of corn and wheat starch in water dispersions caused swelling of the starch granule, some exudate, and eventual loss of original granule integrity. The scanning electron microscope is a sensitive, useful tool to evaluate changes which occur in starch systems.