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ARS Home » Midwest Area » Ames, Iowa » Plant Introduction Research » Research » Publications at this Location » Publication #226029

Title: Effects of Kernel Composition and Starch Structure on Ethanol Yield Produced from Dry-Grind Corn

item Blanco, Michael
item Duvick, Susan

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 6/25/2008
Publication Date: 9/21/2008
Citation: Srichuwong, S., Gutesa, J., Blanco, M.H., Duvick, S.A., Jane, J. 2008. Effects of Kernel Composition and Starch Structure on Ethanol Yield Produced from Dry-Grind Corn [abstract]. In: Cereal Foods World Supplement. American Association of Cereal Chemists International Annual Meeting, September 21-24, 2008, Honolulu, Hawaii. 53(4):A80.

Interpretive Summary:

Technical Abstract: Objectives of this study were to understand how the composition of kernels (i.e., starch, protein, and lipid contents) and the starch structure of dry-grind corn affected the enzyme hydrolysis of starch and the ethanol yield during yeast fermentation. Four lines of corn, designated, 05GEM06031, 06GEM01778, 05GEM02989, and 05GEM06000 with 70.7%, 68.9%, 75.2% and 69.7% starch contents (w/w, dry basis), respectively, were developed and produced by the USDA-ARS GEM project and were used for the study. The corn samples were dry ground, and slurries (20% dry substance) were heated to gelatinize the starch, hydrolyzed using B. licheniformis a-amylase and A. niger glucoamylase, and fermented using Ethanol Red dry yeast for 72 h. The ethanol yields from the dry-grind corn lines were 36.2%, 34.6%, 38.0%, and 34.3% (w/w, dry basis), respectively. The efficiencies of ethanol production, calculated on the basis of the starch contents of corn samples, were 90.3%, 88.4%, 89.1%, and 86.8%, respectively. The ethanol yield was related to the starch content and the protein content, with the correlation coefficient of 0.90 and 0.88, respectively. The efficiencies of ethanol production were correlated (correlation coefficient 0.81) to the average branch chain-lengths of the amylopectins of the four corn lines (DP*17.9, DP19.3, DP19.6, and DP 20.2, respectively) and were also correlated to the onset gelatinization temperatures of the starches with a correlation coefficient of 0.65. The residual starch remaining in the distiller's dry grain (DDG) had the peak molecular weight of DP 85, which was attributed to the amylose-lipid complex. * DP- degree of polymerization