Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2005
Publication Date: 7/1/2005
Citation: Johnston, D., Mcaloon, A.J., Moreau, R.A., Hicks, K.B., Singh, V. Composition and economic comparison of germ fractions derived from modified corn processing technologies. 2005. Journal of the American Oil Chemists' Society.82, No. 8, p.603-608.
Interpretive Summary: A number of processes for removing the germ (oil containing portion) from corn as a co-product during fuel ethanol production have been developed. These processes could potentially be used to improve the overall economics of fuel ethanol production in the United States through increased co-product revenues. The quality of germ derived from these processes has not been adequately evaluated. If the germ produced has significant differences in quality or composition from the current corn germ producing and oil extracting industry (corn wet millers), it could cause difficulty in marketing or lead to decreased value and revenue. In order to determine the value of corn germ derived from these new processes, we determined what factors were important for germ from the wet milling industry and developed a cost determination model using these factors. The oil and protein content of the germ were determined to be the two most significant factors in evaluating the value of the germ. Using this model, we analyzed and compared germ derived from the newly developed corn milling processes and compared these results with germ from the corn wet milling industry. Results of this study should be of value to fuel ethanol processors who are looking for new ways of improving the economic competitiveness of the industry. Increased production of ethanol will in turn benefit farmers by providing expanded markets for agricultural products.
Technical Abstract: Over the past few years a number of new processes for milling corn have been developed. Several of these processes have been developed specifically to isolate germ as a value added co-product to improve the profitability of dry grind ethanol production. The successful implementation of these new processes is highly dependent on having an adequate market for the germ produced. The acceptance and purchase price of germ (determined by owners of extraction facilities) from newly developed processes will be dependent on the quality and composition of the germ derived from these processes. The economic benefits from the new germ recovery processes will ultimately be determined by the composition, quality, and yields of the germ and any other benefits derived from the specific process. The work presented in this study was aimed at determining the quality, composition and yield differences among corn germ produced using the modified processes and comparing this data to the conventional wet and dry milled germ in order to develop an economic value for comparison. A method for calculating the estimated market value for germ produced using alternative processing methods is given. Results showed significant differences in the composition of germ produced by the alternative milling processes as well as the estimated market values. The composition of the different germ fractions produced were found to contain 18-41% oil, 13-21% protein and 6-21% starch depending on the milling process used. The estimated value of germ from these processes varied from as low as $0.058 per pound to a maximum of $0.114 per pound, showing that the specific process used to produce the germ will have major impact on the overall economics of the ethanol process.