MARIA TOMOAIA-COTISEL,  CONSTANTIN COTA, AURORA MOCANU, OSSI HOROVITZ Micro and Nanostructure of Starch Granules from Potato and Maize

MARIA TOMOAIA-COTISEL, CONSTANTIN COTA, AURORA MOCANU, OSSI HOROVITZ Micro and Nanostructure of Starch Granules from Potato and Maize

Abstract:
The present work provides new insights about the micro and nanostructure of native starch granules from potato and maize by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM images revealed the shape and the size distribution of the granules as well as some features, such as holes and wrinkles, on the surface of granules. These data were confirmed by AFM observations which showed the presence of numerous protrusions (nodules) on the granules surface of both starches. The structure of granules surface consisted of small spherical particles of about 30 nm in diameter, identified particularly for potato starch. These nanoparticles might be related with highly branched amylopectin molecules in substantial agreement with amylopectin blocklets (of about 20 nm) model. Larger particles of about 60 nm up to 80 nm were also visualized especially on the surface of maize starch granules representing different associations of amylopectin and amylose. The largest elongated particles of about 100 nm to 200 nm found randomly on granules of both starches might be assigned to arise from the granule-surface components, such as starch carbohydrates attached to granule proteins and phospholipids, in general agreement with starch granule surface composition data. This investigation also supports the complex structural network for the starch granule surface (periphery) and its role in maintaining the integrity of starch granules and in the starch gelatinization process. Keywords: starch granules, potato starch, maize starch, granule surface, supramolecular structuring, scanning electron microscopy (SEM), atomic force microscopy (AFM)

Issue: 2010 Volume 47, Issue 4

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