Extraction of Citrus Oil
The essential oil of citrus fruits is contained in oil sacs in the outer, colored portion of the peel of the fruit (Guenther - V.3, 1949). Distillation only allows small amounts of oil to escape, but using the expression method yields much more oil. After the fruit has been washed and inspected, they proceed on to the removal of juice and oil. One method of oil extraction is the F.M.C. Whole Fruit Extractor. The extraction of juice and oil is desirable in one machine, however, it is important that the juice and oil do not come in contact with each other (Guenther - V.3, 1949). After the fruit is washed, it is sorted by size and introduced into the bottom half of a divided sphere (Guenther - V.3, 1949). When the two spheres (upper and lower) meet, they interlock and exert an almost perfectly distributed pressure (Guenther - V.3, 1949). When pressure is applied, a hole is cut in the bottom of the fruit and the juice then flows out through a tube (Guenther - V.3, 1949). As the pressure increases, the oil glands on the peel are ruptured and the oil emulsion flows through the spheres and is collected in an outer trough (Guenther - V.3, 1949). When the oil and juice have been extracted, the compressed fruit is ejected by flat plates (Guenther - V.3, 1949). The spheres are placed circularly around the machine, which rotates at 20rpm within a stainless steel enclosure which prevents spilling (Guenther - V.3, 1949). The types of fruit which can be extracted by this method include oranges, lemons, limes, and grapefruits.
Source:http://www.wsu.edu/~gmhyde/433_web_pages/433Oil-web-pages/essence/essence-oils.html
