Cereal Chem 45:162 - 171.  |  VIEW ARTICLE
Electron Microscopy of Unmodified and Acid-Modified Corn Starches.

W. C. Mussulman and J. A. Wagoner. Copyright 1968 by the American Association of Cereal Chemists, Inc. 

The morphologies and internal structures of sectioned yellow dent corn, waxy maize and amylomaize starches were studied by light and electron microscopy. Yellow dent and waxy maize starches were similar, but amylomaize starch was quite different. Although the yellow dent and waxy maize starches differ in amylose content, both have similar well-defined concentric lamellae in which electron-thin lamellae are preferentially attacked by acid. Amylomaize starch granules are heterogeneous in morphology, internal structure, and resistance to acid. The morphology varies from approximately spherical granules having knobs or protuberances of various sizes and shapes extending from the surface. The protuberances and the filamentous granules do not show a lamellar structure. Spherical amylomaize granules sometimes have a lamellar structure which is never as well formed as that in yellow dent and waxy maize starches. Acid treatment accentuates the structural heterogeneity in amylomaize granules. When lamellae are present, the acid erodes the electron-thin rings. Some granules or parts of granules are acid-resistant. Others disintegrate into fragments of irregular sizes and shapes.