Orange oil
Orange oil is an essential oil produced by cells within the rind of an orange fruit. In contrast to most essential oils, it is extracted as a by-product of orange juice production by centrifugation, producing a cold-pressed oil. It is composed of mostly d-limonene, and is often used in place of pure d-limonene. D-limonene can be extracted from the oil by distillation.
Composition
The compounds inside an orange oil vary with each different oil extraction. Composition varies as a result of regional and seasonal changes as well as the method used for extraction. Several hundred compounds have been identified with gas chromatograph-mass spectrometry. Most of the substances in the oil belong to the terpene group with limonene being the dominant one. Long chain aliphatic hydrocarbon alcohols and aldehydes like 1-octanol and octanal are second important group of substances.| Compound | Italian Orange Oil Concentration | Valencia orange oil Concentration | Valencia orange oil Concentration | Valencia orange oil Concentration |
| Limonene | 93.67 | 91.4 | 95.17 | 97.0 |
| α-Pinene | 0.65 | 1.4 | 0.42 | – |
| Sabinene and β-Pinene | 1.00 | 0.4 | 0.24 | – |
| Myrcene | 2.09 | 4.3 | 1.86 | 0.03 |
| Octanal | 0.41 | – | - | – |
| Linalool | 0.31 | 0.8 | 0.25 | 0.3 |
| δ-3-Carene | 0.31 | – | – | – |
| Decanal | 0.27 | 0.4 | 0.28 | – |
The presence of sinensetin explains the orange color.
Use
Orange oil is used as a cleaner. It is also used as an additive to certain wax finish/polish such as Howard's Feed-N-Wax Wood Polish & Conditioner.Biological pest control
Orange oil can be used in green pesticides for biological pest control. It can kill ants, and by erasing their scent-pheromone trail indicators disrupts re-infestation.Orange oil is also known to be useful to control, but not exterminate Drywood termites, killing only those who come into direct contact with it.
Aromatherapy material for humans
In the practice of aromatherapy, orange oil is described as providing various benefits, including the possibility of "reducing stress", controlling "anxiety", enabling "relaxation" and "lifting mood". Aromatherapy is a pseudoscience, and much of the purported evidence cited for these claims comes from research which is not double-blinded or controlled.Hazards
The limonene which is the main component of the oil is a mild irritant, as it dissolves protective skin oils. Limonene and its oxidation products are skin irritants, and limonene-1,2-oxide is a known skin sensitizer. Most reported cases of irritation have involved long-term industrial exposure to the pure compound, e.g. during degreasing or the preparation of paints. However a study of patients presenting dermatitis showed that 3% were sensitized to limonene.Limonene has been observed to cause cancer in male rats, by reacting with α2u-globulin, which is not produced by female rats. There is no evidence for carcinogenicity or genotoxicity in humans. The IARC classifies d-limonene under Class 3: not classifiable as to its carcinogenicity to humans.
Limonene is also flammable.