Sequential extraction processing of flaked whole corn: alternative corn fractionation technology for ethanol production
1992
Hojilla-Evangelista, M.P. | Johnson, L.A. | Myers, D.J.
A new approach to fractionating dried, flaked corn (Zea mays L.) by using ethanol was studied. The process involved the simultaneous extraction of crude oil and dehydration of ethanol. Protein was extracted by using a mixture of alkali and ethanol. The procedure provided a means for recycling the alcohol from ethanol fermentation to upstream steps of protein and oil extractions. Ethanol extracted more than 90% of the oil from medium-hard dent corn (Pioneer 3732), soft dent corn (Pioneer 3377), and high-lysine corn. These recoveries were significantly greater than the estimated recovery by wet milling corn and prepress hexane-extraction of the germ. The moisture adsorption capacities of the flaked whole corn (initially at less than 2% moisture content) were 22, 20, and 18 g/kg of soft dent corn, medium-hard dent corn, and high-lysine corn, respectively. These capacities were sufficient to dry 35 g of 95.0% ethanol per 100 g of corn (2.5 gal/bu) initially at less than 2% moisture content to 99.0% ethanol. Ethanol drying could be accomplished simultaneously with oil extraction in a percolation mode. The alcohol-alkali mixture removed as much as 65% of the available corn protein. The freeze-dried protein extracts from the three corn types contained about 80% crude protein (db). The type of corn did not significantly affect the oil and protein yields. The sequential extraction of corn with ethanol was technically feasible and may have considerable economic potential when producing ethanol by corn-starch fermentation.
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