Grapefruit Oil

#### Grapefruit Oil. This oil, which is not strictly an essential oil according to our definitions, is produced by cold expression of the peel of the fruits from a **Citrus **species which presumably evolved from the West Indian "shaddock" fruit. Although not a hybrid, the grapefruit did not exist 400 years ago, and it was still a rarity around the beginning of the twentieth century. Highly developed cultivation and refining of the fruits (better juice, meat, fewer seed, etc.) has, as so often in nature, caused some changes elsewhere in the fruits: the oil from the peel has become milder and sweeter of odor than it was only a few decades ago. **Grapefruit Oil **is produced mainly in Florida, U.S.A., and to a lesser degree in Texas and California. Outside the U.S.A., the West Indies (Dominica island, the Dominican Republic, Jamaica and Trinidad), Brazil, Israel and Nigeria are also producers. All production in the U.S.A. is mechanized; this is also true in Israel. Hand pressing is still carried out in the West Indies. **Grapefruit**** ****Oil**** **is a mobile, yellowish to greenish- yellow or pale orange-yellow oil, possessing a fresh-citrusy, rather sweet odor and a similar taste. As mentioned above, the bitterness particularly known from European and Middle-Eastern fruits and peels, is no longer found in today's American grapefruit oil. The odor resembles that of sweet orange oil to a certain degree, but also has notes in common with bitter orange oil. Thus, grapefruit oil is quite useful in bergamot compositions and for all modifications of citrus notes in perfumery. The main use, however, is in flavors, particularly in soft drink flavors. A partially deterpenized grapefruit oil is often preferred for this purpose. More than 90% of the grapefruit oil is made up of monoterpenes, mainly d-limonene which has only a minor influence upon the characteristic flavor of the oil. Like all other citrus oils, grapefruit oil is not very stable and deteriorizes easily upon exposure to moisture, air and daylight. Antioxidants and oxygen-free storage conditions can prolong the shelf-life of these oils. Certain combinations of antioxidants are effective in concentrations of 0.002% which is far below the threshold of flavor or odor perception. Terpenes are particularly disadvantageous in soft drink flavors since they tend to create a "ring" of opaque emulsion inside the bottleneck at the surface—or on the side of the bottle if it is stored lying down. However, a certain amount of terpenes is necessary to produce the natural freshness of citrus oils. Thus, "concentrated" grapefruit oils are often used for the above flavors. Fifty percent or more of the monoterpenes are removed by careful vacuum distillation at less than 30° C. "Cold processed" deterpenized oils are produced by alcohol washing (see **Terpeneless Oils**, Part One of this book). Due to the tremendous growth of the grapefruit industry, the oil is no longer the rarity or scarce item it was only 15 or 20 years ago. Indeed, the grapefruit juice processors are faced with a problem of disposing of all the oil they can produce. Not only is there the machine-pressed oil, but also the **Distilled**** ****Grapefruit**** ****Oil,**** **produced by steam distillation of the crushed peels and residues from the juice extraction. Smaller quantities of oil is obtained during the evaporation of juice which inevitably contains some oil. **Distilled**** ****Grapefruit**** ****Oil**** **is a poor flavor material. It may have a comparatively high content of aldehydes, but the content of other oxygenated compounds in the distilled oil is negligible. The distilled oil finds its way into low cost perfumes, industrial fragrances, etc., often mixed with other distilled citrus oils and marketed under the name of **Citrus Oil. **Even the seeds from the grapefruit are now used for production of a fatty (vegetable) oil. **Grapefruit**** ****Oil**** **(cold pressed) is rarely adulterated. There are different qualities of the oil and it is important to get a freshly produced or carefully stored oil. However, the **Distilled**** ****Grapefruit**** ****Oil **can be used as a diluent for the expressed oil. This fraud will show up not only in the decrease of evaporation residue (very small in distilled oils), but also in the lack of flavor richness of the adulterated oil in an organoleptic test.