Within the acid lime classification there are two groups whose essential oils are of commercial interest: the Key, Mexican or West Indian lime (Citrus aurantifolia Swingle) whose fruit is small and seeded and the Persian or Tahiti lime (Citrus latifolia Tanaka) with larger seedless fruit. According to the Iiterature, the Persian lime is a hybrid, one of the parents being the Key lime and the other most likely a lemon or a citron with the latter being the more probable (Sacco and Calvarano, 1981).
The most important areas for Key lime production and processing are Mexico, Peru and Haiti. Florida and Brazil are the major producers of the Persian lime.
Two common methods are used for oil production: distillation and centrifugation. To obtain the distilled oil the whole fruit is fed into a screw press where the oil cells within the peel are ruptured by pressure resulting in a juice-oil emulsion. This emulsion is then steam distilled to recover the oil. The cold-pressed oil is obtained by passing the fruit through machinery which ruptures the oil ceIIs either by puncturing or rasping. The oil is then washed away with water, forming an oil-water emulsion which can he separated by centrifugation. Cold-pressed Persian lime and the Type B Key lime oils are obtained by this method. A different kind of oil, type A Key lime is obtained when the oil-juice emulsion obtained in the screw press is centrifuged instead of distilled.