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Variability of Reaction Efficiencies and Pasting Properties of Acetylated Dent Corn Starch from Various Commercial Hybrids

¹Graduate fellow, academic professional, research specialist, academic professional, and assistant professor, respectively; Agricultural Engineering, University of Illinois, Urbana, IL 61801. ²Professor, Veterinary Biosciences, University of Illinois, Urbana, IL 61801. ³Corresponding author. E-mail: krausch@uiuc.edu. Phone: 217-265-0697. Fax: 217-244-0323.

Genetic diversity in corn (maize) has contributed to variability in corn processing characteristics. Differences in acetylated dent corn starch pasting properties and reaction efficiencies due to hybrid were assessed. Ten dent corn hybrids grown during 1998 and nine dent corn hybrids grown during 1999 were wet-milled in the laboratory. Starch from each hybrid was modified using a laboratory-scale acetylation procedure. NaOH consumed and reaction time were recorded for each reaction. A Rapid Visco Analyser (RVA) was used to measure starch pasting properties. Acetyl content was measured by a spectrophotometric method, from which reaction efficiency was calculated. Reaction efficiencies were observed at 35–56%. Overall reaction efficiencies for starch samples from 1998 hybrids were lower than samples from 1999 hybrids. Differences in peak viscosity, trough viscosity, final viscosity, setback, and pasting temperature were found among 1998 hybrids. Differences in trough viscosity, final viscosity, and breakdown were found among 1999 hybrids.