Orange sweet oil

Description

Sweet orange is an evergreen tree of Oriental origin, 4 to 6 m (13 to 20 ft.) high. It has a cylindrical trunk, alternate leaves, and odorous flowers and fruits. The fruit has a green epicarp that turns yellow on ripening; a white, spongy mesocarp; and an endocarp consisting of succulent segments bearing seeds.
The Mediterranean countries in which it is cultivated include Italy (Sicily, Calabria, and Campania), Algeria, Tunisia, Morocco, Spain, and Israel; in addition, very important production occurs in California and Florida. It has an enormous worldwide economic importance. In the various countries, cultivation is geared toward the production of (1) fruits for immediate consumption and (2) fruits to be used for the production of juices or essential oils. For this purpose, the most suitable varieties have been selected.
The parts used are the leaves (and small twigs), flowers, ripe fruits, small, whole, unripe fruits, peels, and juice. The oils and various derivatives from orange, sweet have a mild to highly bitter, astringent flavor and a characteristic aroma. The juices are sweet and acidic or tart.
Petitgrain essential oil of sweet orange can be obtained from the leaves, small, whole unripe fruits, twigs, and flowers by steam distillation. Its production is low because of its limited application (perfumery).
Sweet orange essential oil is extracted from the peels of partially ripened fruits in 0.4 to 0.5% yields using suitable machinery fpr the rupturing of the oil-bearing cells (expression). A less valuable quality of essential oil is obtained by steam distillation of peels.

Chemical properties

Sweet orange oil is obtained from the peel of the fruits of Citrus sinensis (L.)Osbeck. It is a yellow to reddish-yellow liquid with the characteristic odor of orange peel and may become cloudy when chilled. Sweet orange oil is often produced in combination with orange juice (mainly in the United States and in Brazil and, much smaller quantities, also in Spain and Israel).
d²⁰₂₀ 0.842–0.850; n²⁰_D 1.4700–1.4760; α²⁰_D +94 ° to +99 °; evaporation residue: 1–4%.
The oils have a high terpene monoterpene hydrocarbon content. The main constituent is (+)-limonene (93–96%). Important for the typical sensory properties are components present only in low concentrations such as octanal (0.1–0.4%), decanal (0.1–0.7%), and citral (0.08–0.3%). The sesquiterpene aldehydes α-sinensal and β-sinensal (0.01–0.06%), which contribute particularly to the special sweet orange aroma, also occur in other citrus oils, although in lower concentrations. A number of higher boiling point, nonvolatile constituents contributing to the flavor and color of orange oil have been described in the literature.
Worldwide production of cold-pressed orange oil exceeds 50 000 t/yr. The main producer is Brazil (30 000 t), followed by the United States (20 000 t). The main uses of orange oil are the flavoring of beverages and confectioneries and perfuming eau de cologne, soaps, and household products.

Chemical properties

From leaves; small, whole, unripe fruits; twigs; and flowers: Petitgrain oil of sweet orange can be obtained from the above by steam distillation. Its production is low because of its limited application (perfumery). From fruit (peels): Sweet orange essential oil is extracted from peels of partially ripened fruits in 0.4 to 0.5% yields using suitable machinery for the rupturing of the oil-bearing cells (expression). A less valuable quality of essential oil is obtained by steam distillation of peels. Sweet orange oil has a characteristic odor and typical aromatic flavor. The cold-pressed sweet orange oil is obtained by expression, without the use of heat, from the fresh peel of the ripe fruit. It has a characteristic odor and taste of the outer part of fresh, sweet orange peel.

Physical properties

Sweet orange essential oil is a clear, mobile liquid, with a yellow-to-orange color. The coldpressed oil is miscible with dehydrated alcohol and carbon disulfide. It is soluble in glacial acetic acid. The oil may contain a suitable antioxidant. Physical–chemical characteristics of the oil vary according to origin.

Occurrence

Found in the peel of the fruit Citrus sinensis (Linn.) Osbeck (Fam. Rutaceae) (Gildemeister & Hoffman, 1959; Guenther, 1949).

Preparation

By expression of the peel of the ripe fruit (Arctander, 1960).

Definition

Extractives and their physically modified derivatives. Citrus sinensis, dulces, Citrus.

Essential oil composition

The essential oil contains more than 90% limonene, in addition to aldehydes (decylic, octylic, nonylic and dodecylic), citral acids and esters. From the raw essence of sweet orange, the terpeneless essence can be obtained by vacuum distillation (with heat), by chromatographic separation or by extraction with low-proof alcohol. By washing the oil with low-proof alcohol, one obtains the soluble essence of sweet orange with yields of 1:50, 1:100, 1:200, 1:400; the essence is used in the flavoring of carbonated beverages, syrups, liqueurs, aperitifs and other products. Orange pastes for use in carbonated beverages are prepared using terpeneless essential oil, juices, pectins and sugars (Burdock, 1997).

Safety Profile

A skin irritant. Questionable carcinogen with experimental neoplastigenic data. When heated to decomposition it emits acrid smoke and irritating fumes.