Bitter Orange Oil

#### Orange Oil, Bitter. The "essential" oil from the peel of the almost ripe fruit of the bitter orange tree, **Citrus**** ****Aurantium**, *subspecies** **amara,** *is produced almost exclusively by expression. Thus it is strictly not a true essential oil according to current definitions. It contains some non-volatile matter. Like most other citrus fruits, the bitter orange exists in numerous varieties, and bitter orange oil varies considerably in odor and flavor according to its geographical origin. The main producers of bitter orange oil are: Spain, Guinea, the West Indies (Jamaica, Cuba, Haiti, Dominican Republic, Puerto Rico), Italy (Sicily), Brazil, etc., while the U.S.S.R., Mexico, China, Tanganyika, France, etc. are minor producers. In Italy, the bitter orange tree serves for the grafting of other citrus trees on a wide scale, due to the resistance of this bitter orange tree (trunk) to serious diseases. After expression of the oil by hand or by machine, some producers submit the peels to steam distillation, thus obtaining a further, small yield of a very poor oil. Unfortunately, this oil is often added to the cold-pressed oil. To the author's knowledge, distillation is never performed in Spain or Guinea, and this fact could be part of the reason for the outstandingly high flavor and odor quality of the bitter orange oils from these areas. Cold pressed bitter orange oil is a mobile liquid of dark yellow to olive-yellow or pale brownish yellow color. The odor is very peculiar, fresh and yet "bitter" in the sense of "dry", but with a rich and lasting, sweet undertone. There are notes which remind of bergamot, grapefruit and sweet orange, but overall, the odor is distinctly different from that of other citrus oils. It is a different type of freshness, a peculiar floral undertone which occasionally shows indolic notes, and a comparatively good tenacity. **Bitter Orange Oil **is used extensively in flavors where it forms the main ingredient in the "orange **sec" or "triple **sec" liqueur flavors, and also acts as an important modifier and intensifier in common sweet-orange flavors for soft drinks, etc. It lends body and pleasant "twists" to a plain sweet-orange flavor, and its great power makes it economical in use. The average use level would be about 2.00 mg% to 5.00 mg%. Still higher concentrations are recommended for straight bitter orange liqueur flavors. The **Minimum**** ****Perceptible**** **is about 0.02 mg% to 0.04 mg%. These figures are based upon experiments with good Spanish and good Guinea bitter orange oils. Not even the best of the West Indian oils can claim equally low figures. They would be about 1 ½ to ½ times the above mentioned figures. For perfumes, the bitter orange oil finds use among the other citrus oils in all types of colognes, chypres, fougères, fresh fragrances, topnotes, aldehydic citrus bases, etc., and it is one of the most common ingredients in artificial bergamot oil. It blends excellently with lavandin and lavender, rosemary and sage clary, oakmoss and labdanum, linalool and linalyl propionate, etc. and olibanum resinoid is an excellent fixative for the volatile bitter orange oil. As mentioned above, the quality of this oil varies significantly, and for use in flavors, the author would rate the Guinea and the best Spanish oils highest. Some Italian and West Indian oils would rate second, and the Tanganyika oil is often very good. However, there are large lots of very poor oils on the market, and this fact may have ruined the reputation of the oil and killed many perfumers' and flavorists' interest in bitter orange oil. A thorough organoleptic and olfactory analysis of many samples will usually convince the potential buyer that there are bitter orange oils worth the comparatively high price demanded for this item. Being mainly a cold-pressed and often hand-pressed oil, it is obviously more costly to produce than e.g. sweet orange oil. Flavor houses often make concentrates of bitter orange oil, and various concentrates are described in the following monograph. Bitter orange aroma and bitter orange aroma-distillate are prepared as described in Part One of this book (see **Aroma**** **and **Aroma-Distillate**). They are particularly suited for use in liqueur flavoring and in flavors for carbonated beverages. Bitter orange oil is frequently adulterated with citrus oil terpenes, distilled oils of bitter orange, sweet orange, grapefruit, etc., or with d-limonene. Good oils are often sold out even before they are produced (contracted by the larger flavor houses), and the oil can be almost totally unavailable at some times of the year. The annual world production is fluctuating but averages about 30 metric tons.