CLOVES

Chemical Properties

Cloves are dried, unopened flower buds and twig tips of the evergreen tree Eugenla caryophyllata Thunberg. The clove tree can grow to 20 m (66 ft), and is native to tropical regions of Asia (Molucca Islands, Réunion, Penang, Zanzibar, Pemba, Tanzania, Malagasy Republic and Madagascar) and South America. Cloves have been used in China and India for centuries, even before the time of Christ. Cloves entered the western European market in the sixth century. In the United States, cloves have been used since colonial times. The principal use of cloves is in flavoring of foods and tobacco; minor uses of cloves are as analgesics and germicides.
The quality of the clove product is dependent on the development stage of the flower bud. Clove buds are typically dark brown with four calyx lobes. Buds and stems are harvested by hand, sun-dried and marketed. The highest quality buds are sold as whole cloves, whereas lower quality buds, stems and leaves are used in the production of essential oils. The aroma is strongly aromatic and spicy. The flavor is warm. A major component of clove is eugenol, which has served as a medicinal agent for the treatment of gastric and duodenal ulcers, disinfectant for root canals, local anodyne for relief of hypersensitive dentin and inflamed vital pulps and a component of temporary fillings for carious teeth.

Occurrence

Cloves are found in South America, Sumatra, and Tanzania.

Uses

Cloves are used mainly as an essential oil; a treatment for toothache; a topical anesthetic in dentistry; and an antiseptic, antibacterial, and antiinfl ammatory for the oral mucosa. They may also be used as a fl avoring or antimicrobial in formulas.

Essential oil composition

Clove buds are known to yield approximately 15 to 20% of the volatile oil that is responsible for the characteristic aroma and flavor. The stems yield about 5% and the leaves yield about 2% oil. The bud also contains a tannin complex, a gum and resin and a number of glucosides of sterols. Clove bud oil contains mainly eugenol (4-allyl-2-methoxyphenol). Other constituents include acetyleugenol (10%) and small quantities of gallic acid, sesquiterpenes, furfural, vanillin and methyl-n-amyl ketone.

Raw materials

Preparation Products