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Using Microwave Heating and Microscopy to Estimate Optimal Corn Germ Oil Yield with a Bench-Scale Press

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Journal of the American Oil Chemists' Society

Abstract

The increase in ethanol production from corn has prompted development of processes to separate corn germ. The corn germ co-product would be a source of corn oil if a practical oil separation process were also developed. We carried out bench-scale corn-germ-pressing experiments to determine the maximum potential oil recovery which were then used to estimate commercial germ crushing costs. Corn germ was preheated in a microwave oven and oil was then extracted with a bench-scale press. Preheating the germ was necessary to obtain good oil yields. The uniform heating of the microwave oven more closely resembles compressive heating of commercial scale presses than does oven heating. Three different microscopic techniques were used to examine the effects of microwave and conventional-oven heating on corn germ. Microscopy revealed that microwave heating heated oil in the germ more quickly than the other components of the germ. Heating by both methods destroyed lipid body membranes and oil coalesced and pooled. Less oil could be pressed from germ initially containing 3–6% moisture than germ containing 15–20% moisture. Maximum oil recovery of about 65% was obtained for all germs tested when the optimum press temperature and germ feed moisture were used.

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Acknowledgments

The authors thank Michael F. Dallmer for expert technical assistance, W.J. Duensing of Bunge North America who gave the authors valuable insight into the nature of the dry-milling industry, R.L. Stroup, who shared his knowledge of soybean mill operations and costs.

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Authors and Affiliations

  1. US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA, 19038-8598, USA

    L. C. Dickey, P. H. Cooke, M. J. Kurantz, A. McAloon, N. Parris & R. A. Moreau

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  1. L. C. Dickey
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  2. P. H. Cooke
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  3. M. J. Kurantz
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  4. A. McAloon
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  5. N. Parris
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  6. R. A. Moreau
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Corresponding author

Correspondence to L. C. Dickey.

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Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture.

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Dickey, L.C., Cooke, P.H., Kurantz, M.J. et al. Using Microwave Heating and Microscopy to Estimate Optimal Corn Germ Oil Yield with a Bench-Scale Press. J Amer Oil Chem Soc 84, 489–495 (2007). https://doi.org/10.1007/s11746-007-1051-7

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  • DOI: https://doi.org/10.1007/s11746-007-1051-7

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