Orange oil is an essential oil produced by cells within the rind of an orange fruit (Citrus sinensis 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 (greater than 90%) d-limonene, and is often used in place of pure d-limonene. D-limonene can be extracted from the oil by distillation.
Limonene gives citrus fruit their familiar aroma, and is therefore used in perfume and household cleaners for its fragrance. It is also an effective, environmentally friendly, and relatively safe solvent, which makes it an active ingredient of choice in many applications, such as, adhesive and stain removers, cleaners of various sorts, and strippers. Limonene is also highly useful in agriculture.
The compounds inside an orange oil varies with each different oil extraction. Composition variety happens 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 [%]|
|Sabinene and β-Pinene||1.00||0.4||0.24||–|
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 (formed by aerial oxidation) 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.
Biological pest control
Orange oil can be used in biological pest control green pesticides. It can kill an ant, as well as a whole colony of ants. Orange oil also erases an ant's scent-pheromone trail indicators and disrupts re-infestation activities in ants. Their use in organic farming is becoming increasingly important because of their non-toxic nature. They are commonly used in kitchens to safely repel ants.
Orange oil is also known to be useful to control, but not exterminate Drywood termites (Incisitermes.) The solvent properties will generally kill the termites that come into contact with orange oil.
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