Clove essential oils extraction

Essential Oils Extraction of Oil of Cloves by Steam Distillation... 

Essentia.1 Oils. Essential oils (qv) are extracted from the flower, leaf, bark, fmit peel, or root of a plant to produce flavors such as mint, lemon, orange, clove, cinnamon, and ginger. These volatile oils are removed from plants either via steam distillation, or using the cold press method, which avoids heat degradation. Additional processing is sometimes employed to remove the unwanted elements from the oils, such as the terpenes in citms oils which are vulnerable to oxidation (49,50). 

Production. Since sufficient eugenol can be isolated from cheap essential oils, synthesis is not industrially important. Eugenol is still preferentially isolated from clove leaf and cinnamon leaf oil (e.g., by extraction with sodium hydroxide solution). Nonphenolic materials are then removed by steam distillation. After the alkaline solution is acidified at low temperature, pure eugenol is obtained by distillation. 

The odor of a freshly crushed mint leaf, like many plant odors, is due to the presence in the plant of volatile C10 and Ci5 compounds, which are called terpenes. Isolation of these substances from the various parts of plants, even from the wood in some cases, by steam distillation or ether extraction gives what are known as essential oils. These are widely used in perfumery, as food flavorings and medicines, and as solvents. Among the typical essential oils are those obtained from cloves, roses, lavender, citronella, eucalyptus, peppermint, camphor, sandalwood, cedar, and turpentine. Such substances are of interest to us here because, as was pointed out by Wallach in 1887 and reemphasized by Ruzicka in 1935, the components of the essential oils can be regarded as derived from isoprene ... 

Volatile or essential oils are usually obtained from the appropriate plant material by steam distillation, though if certain components are unstable at these temperatures, other less harsh techniques such as expression or solvent extraction may be employed. These oils, which typically contain a complex mixture of low boiling components, are widely used in flavouring, perfumery, and aromatherapy. Only a small number of oils have useful therapeutic properties, e.g. clove and dill, though a wide range of oils is now exploited for aromatherapy. Most of those employed in medicines are simply added for flavouring purposes. Some of the materials are commercially important as sources of chemicals used industrially, e.g. turpentine. 

Guan, W., Li, S., Yan, R., Tang, S. and Quan, C. (2007) Comparison of essential oils of clove buds extracted with supercritical carbon dioxide and other three traditional extraction methods. Food Chemistry 101 (4), 1558-1564. 

Della Porta, G., Taddeo, R., D Urso, E. and Reverchon, E. (1 998) Isolation of clove bud and star anise essential oil by supercritical C02 extraction. Lebensmittel-Wissenschaft und Technologie 31, 454-460. 

Clove oil may be obtained from cloves by steam distillation. A number of other spices may be used for extracting other oils (9,10) whose structures are shown in Table 16-1. The essential oils are rich in one main compound and since all components are UV absorbing, the fixed wavelength detector at 254 nm is adequate for detection. Liquid chromatography is a rapid analytical tool in analyzing the essential oils. 

Extraction of food ingredients with a high content of essential oils, like cloves, camomille, marigold, cinnamon... 

For all extracts for which the content of essential oils is important, extraction pressures above 300 bar are not suitable. If raw materials like cloves, cinnamon, camomille flowers are extracted at 500 bar the extraction yields are higher compared to 300 bar, but there are so many additional undesired substances in the extracts like dyes, waxes etc. that these extracts are not acceptable by the market. 

The application of higher pressures for herbs and spices like camomille flowers, cinnamon bork, clove and others gives no advantage at all, because the yield regarding essential oils is equal and additional extracted substances are not desired. 

Recently a method has been described in the patent literature for the fractionation of essential oils using a fluorinated solvent.Oils studied included clove bud and bergamot, and fractionations could be performed in a semi-continuous mode. Fluorous solvents, as very non-polar media, offer an interesting alternative to the aqueous or alcoholic solvent approaches typically used in natural product extractions. However, it is unlikely that the technique will become widely used in this field. 

The biggest market for essential oils is for perfumes, and, as might be expected, prices for these oils reflect their rarity. Recently, worldwide production of orange oil was 1500 tons and it sold for 0.75 per lb, while 400 tons of clove oil sold for 14.00 per lb, and 10 tons of jasmine oil sold for 2000 per lb. These three oils represent the most common extractive processes orange oil is obtained by expression (squeezing) of the peel in presses clove oil is obtained by steam distillation, as will be performed in this experiment and jasmine oil is obtained by extraction of the flower petals using ethanol. 

Physical processes (see chapter 2) for isolation of natural flavouring substances include distillation, solvent extraction (including supercritical carbon dioxide), and chromatography. Major sources are essential oils. These may be derived from various parts of aromatic plants such as fruits (e.g. citms, fennel), fmit parts (e.g. mace), flowers (e.g. safflower), flower parts (e.g. saffron), flower buds (e.g. clove), bulbs (e.g. onion), barks (e.g. cinnamon), leaves (e.g. basil), leaves and twigs (e.g. mandarin petitgrain), rhizomes (e.g. ginger), roots (e.g. angelica), and seeds (e.g. mustard). 

Various oils present in natural extracts have been classified as fixed oils or high boiling oils and essential or volatile oils. Very popular fixed oils are neem oils (nonedible), coconut, ground nut, soya, Sunflower, mustard etc. oils (edible). Some of the popular essential oils are rose oil, eucalyptus, lemon grass, jasmine, etc. oils of fragrance grade and cumin, coriander, cardamom, clove etc. of flavor grades. 

A food extract, such as a lemon extract, is really not a chemical extraction but consists of the essential oils that are mechanically pressed out of lemon skin and then kept in a 45% solution of alcohol. A drug extract is called a tincture. Tinctures are usually alcohol solutions and are liquid-solid extractions. Examples are the tincture of iodine, oil of wintergreen, oil of clove, and oil of peppermint. Cosmetic extracts such as ambergris, musk, castor, and benzoin, are called essences and are used to make perfumes. 

Oil for Ear Infection 5 cloves garlic 4 ounces (118 ml) olive oil 20 drops essential oil of eucalyptus 15 drops grapefruit seed extract... 

Since the work of Chfford et al., several studies of the small-scale extraction of essential components have been made and the work and methods have been reviewed [62-64]. Work has been carried out on eucalyptus [65] peppermint [66, 67], savory [67], laurel [68] and Thymbria spicata [69]. These reach similar conclusions to those made above for rosemary, wild marjoram and clove and in some cases comparisons with steam distillation and other methods have been made [58, 60, 61, 66, 68]. In addition to essential oil components, work is also being carried out on the extraction of compounds for analytical purposes [70, 71], including the extraction of metals [72, 73]. Other extractions of medical and industrial interest are being car-... 

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