Expander-extruders soybean processing

Extruders. Extruders, or expanders, are widely applied in the oilseed industry, but mostly for press-cake conditioning in canola oil extraction, and for extruding soybean flakes into expanded collets for improved extraction yield. Extruders as cookers are used in some soybean extraction plants to achieve enzyme inactivation. Lusas investigated inactivation of enzymes during extrusion of soybean (69). Extruders could be used to pretreat canola seed to assist prepressing and to inactivate the enzymes however, commercial application of this process in canola industry is not known. 

More efficient procedures utilize expanders and extruders to convert the flakes into collets, or porous, spongelike material. Collets are larger and less fragile than soybean flakes aiding in the oil extraction and drainage process. This also minimizes the amount of hexane that needs to be recovered in the desolventizer. 

Introduction of the expander, a high-shear extruder with an interrupted-flight screw, in the mid-1980s revolutionized oilseed extraction practices. Essentially all solvent-extracted cottonseed, and approximately 70 percent of domestic soybean tonnage now are processed... 

There are mainly two types of wet extruders that are being used to process soybeans (1) segmented single-screw extruders and (2) interrupted flight extmders/ expanders. 

The introduction of the expander, a high-shear extruder with cut-flight screw, revolutionized oilseed extraction practices in the latter half of the 1980s. By 1990, over 80 percent of the soybean and cottonseed tonnage processed domestically used this technique. The expander heats, homogenizes, and shapes... 

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