Cereal Chem 72:385-388  |  VIEW ARTICLE

Effect of Eggshell on Properties of Corn Starch Extrudates.

K. Takamine, S. Bhatnagar, and M. A. Hanna. Copyright 1995 by the American Association of Cereal Chemists, Inc. 

Corn starch was extruded in a single-screw Brabender laboratory extruder at 140 C barrel temperature and 140 rpm screw speed. Expansion ratio, bulk density, shear strength, percentages of closed and open pores, porosity, and molecular degradation of extruded starch were measured. Addition of up to 10% eggshell resulted in decreases in expansion ratio, bulk density, and percentage of open pores and increases in shear strength, percentage of closed pores, and porosity of extrudates. Cross-section became smaller with a greater number of round and uniform sized cells for extrudates with added eggshell. Gel permeation chromatographic fractionation of starch, extruded with eggshell, showed extensive degradation of fraction I with increasing eggshell concentrations. The eggshell appeared to have provided nucleations sites for water vaporization as the material exited the die of the extruder.