MATERIAL


Figure 1. Schematic of an Anderson expeller. (Courtesy of V. H. Anderson
 Company, Cleveland, Ohio.)


may be carried out in the steam jacketed kettles such as the
stack cooker shown in Figure 2. Preliminary experiments with
citrus seeds showed that satisfactory expelling could be accom-
plished if the meal was cooked to about 220 F (51).
 Oil Expression and Extraction.-While the oil from citrus
seeds has been removed by expression in an expeller (Figure 1),
the minimum oil content to which oil cake can be reduced by this
method is approximately 2% to 3%. To remove this 2% to 3%
of oil, it would be necessary to use some type of solvent extrac-
tion. If solvent extraction of citrus seeds is to be used, it may
be in conjunction with expelling, as the oil content of the whole
seed is about 40% on a dry basis. Operations such as flaking
will be necessary, since efficiency of solvent extraction is much
more dependent upon particle size or flake thickness than is
mechanical expression. For soybeans, commercial solvent ex-
tractions with hexane commonly reduce the oil content of the
dry solid residue meal to about 0.5%.
 Refining.-Citrus seed oil is not refined in Florida, but sold
as crude oil to out-of-state manufacturers, who may then refine
it. Refining is necessary if the oil is to be used for edible pur-
poses, since the crude oil contains nonglyceride impurities such
as free fatty acids, phosphatides, pigments, and bitter materials