ABSTRACT
World vegetable oil consumption reached 129.5 million metric tons in 2009, and soybeans contributed 28% of the total production (Soystats Web site). The use of ªammable hydrocarbon solvents, mainly hexane, is the current industrial process applied to oilseeds to satisfy the world demand for vegetable oil. The use of petroleum-derived hexane has been the most ef™cient procedure considering both extraction yield (>95% oil extracted from the seeds) and economic pro™tability. For the conventional soybean extraction process, pretreatment steps for optimal hexane extraction include cleaning, tempering, cracking, dehulling, conditioning, ªaking, and sometimes expanding followed by solvent extraction, meal desolventizing and toasting, and miscella evaporation and oil stripping (Johnson 2008). The defatted meal (solid residue) is then cooled, ground, and used for animal feeding applications. The normal meal desolventizing/ toasting procedure is replaced with ªash desolventizing when making food-grade defatted soy ªour (Johnson 2008). Worldwide, soybean meal (SBM) is the primary source of protein for poultry and livestock industries. In the United States, about 54% of all SBM is used to feed poultry, while 26% is consumed by swine (Stein et al. 2008).
