Studies on the Quality of Soybean Oil: Extraction Method, Soybean Type, and Oxidative Stability

209 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1992.The Extrusion Aided Screw Press process is an alternative method for the production of soybean oil. It combines short time high temperature extrusion with a conventional screw press to obtain soy oil and meal of high quality. Different soybean varieties (some with altered fatty acid, lipoxygenase, and trypsin inhibitor levels) produce oils with different tocopherol, sterol, phospholipid, and metal contents as compared to common soybeans (U.S. grades #2 and #3, respectfully). Oxidative stabilities of different soybean oils, as measured by the Oxidative Stability Instrument (OSI), peroxide value development, and headspace volatile development indicate the oil produced from the lower quality common soybeans (U.S. grade #3) and soybeans with altered fatty acid composition were most resistant towards oxidation, followed by the other three types of soybean oil, all of which demonstrated similar oxidative stability. The OSI appears to correlate better with peroxide value development and higher molecular weight oxidation breakdown compounds (heptanal, and 2,4-decadienal) than with shorter chain oxidation degradation compounds (pentanal, hexanal, and hexenal). In addition to use with fats and oils, the OSI method demonstrated its ability to determine an induction period index with intact snack food products, such as corn chips, potato chips, dry roasted peanuts, and pork rinds.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD