Food Lipids: Chemistry, Nutrition, and Biotechnology

Figure 5 Steps in processing soybeans into meal and edible oil.
contains waxes on the outer surface as a natural protective mechanism of the seed.
These waxes must be removed during latter oil-refining steps, often by winterization
or cold centrifugation; otherwise, the wax may become insoluble at cold temperatures
and make the oil unattractively cloudy and cause emulsions such as mayonnaise to
separate. Removing the hulls can alleviate these wax problems. On the other hand,
hulls can be helpful at times, such as by providing fiber to allow easier hard pressing
or to enhance solvent drainage, and thus they are not always removed.
Dehulling must be done carefully, to ensure that the meat is not broken into
too many small pieces, which would be difficult to separate from the hull. Also,
crushing of meats during dehulling causes oil cells to be ruptured, freeing the oil.
This damage should be minimized to prevent absorption of liberated oil by hulls that
are removed. Either one of these problems increases the oil content of the hulls and
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