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Variability in Starch Acetylation Efficiency from Commercial Waxy Corn Hybrids

¹Graduate fellow, academic professional, research specialist, and academic professional, respectively; Department of Agricultural Engineering, University of Illinois, Urbana, IL. ²Professor, Veterinary Biosciences, University of Illinois, Urbana, IL. ³Assistant professor, Agricultural Engineering Department, University of Illinois, Urbana, IL 61801. ⁴Corresponding author. E-mail: krausch@uiuc.edu. Phone: 217-265-0697. Fax: 217-244-0323.

Raw material variability is common for starch processors and is responsible for increased processing costs. In this study, variability of starch acetylation due to hybrid influence was quantified. Six waxy corn (maize) hybrids from 1998 and five waxy corn hybrids from 1999 were wet-milled in the laboratory. Starch obtained from each hybrid was modified according to a laboratory-scale acetylation procedure. To evaluate reaction efficiency, reaction rate, acetyl content, pH, and amount of NaOH used were recorded for each reaction. After modification, a Rapid Visco Analyser (RVA) was used to characterize modified starches and determine differences in modified starches from different hybrids. Using the same acetylation protocol, reaction efficiencies were observed at 47–73%. Reaction efficiencies were significantly lower for 1998 hybrids (50.0%) compared with the efficiency observed for the same hybrids grown in 1999 (62.7%). Acetylated starch from 1999 had increased peak, trough and final viscosities and increased reaction efficiency as compared with acetylated starch from 1998. Differences in setback were observed among 1998 hybrids for acetylated samples. Differences in trough and final viscosity were observed among 1999 hybrids for acetylated and native (unmodified) samples. Differences in breakdown among 1999 hybrids also were observed for native samples.