INFLUENCE OF MOISTURE CONTENT AND COOKING ON THE BENCH SCALE SCREW PRESSING OF CORN OIL

Authors: Moreau, Robert; Johnston, David; Hicks, Kevin

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 3/8/2006
Publication Date: 3/8/2006
Citation: Moreau, R.A., Johnston, D., Hicks, K.B. Influence of moisture content and cooking on the bench scale screw pressing and pre-pressiing of corn oil from corn germ. Oil Mill Gazetteer 111:8-10 March 2006.

Interpretive Summary:

Technical Abstract: Samples of corn germ were obtained from a commercial corn wet mill (factory dried to about 3% moisture) and a commercial corn dry mill (undried, produced in the mill with about 13% moisture). The germ samples (200 grams each) were cooked for various times in either a conventional oven at 180 deg C, or a microwave oven at 1500 W. Bench-scale single screw pressing was then performed. With the dry milled corn germ, no oil was obtained from the uncooked germ. A maximum yield of about 5% oil (26% of total oil recovery, TOR, relative to hexane extraction) was obtained by cooking the dry milled germ for 6.5 minutes in a conventional oven at 180 deg C before pressing. A maximum yield of about 7% oil (37% TOR) was obtained by cooking the dry milled germ for 4.5 minutes in a microwave oven at 1500 W before pressing. With the wet milled germ, yields of about 7% oil (18% TOR) were obtained with the uncooked germ and yields increased to a maximum of about 22% oil (56% TOR) by cooking in a conventional oven at 180 deg C for 5 min or a maximum of about 17% oil (44% TOR) by cooking for 4 minutes in a microwave oven at 1500 W. These results indicate that microwave and conventional oven cooking are both effective pre-treatments before pressing. Microwave preheating resulted in higher oil yields with dry milled germ and conventional oven pre-treatment resulted in higher oil yields with factory-dried wet milled corn germ.