Lemon essential oil

Orange essentials oil Lemon essentials oil Grapefruit essentials oil Carrot (root)... 

United States Exports of Spices and Oleoresins. The United States (ca 1993) is the foremost grower of peppermint, spearmint, orange, lemon, lime, and grapefmit products. The mints are processed to essential oils, and the citms fmit are sold as fresh fmit or processed to fro2en... 

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). 

Exceptions to the simple definition of an essential oil are, for example, gadic oil, onion oil, mustard oil, or sweet birch oils, each of which requires enzymatic release of the volatile components before steam distillation. In addition, the physical process of expression, appHed mostly to citms fmits such as orange, lemon, and lime, yields oils that contain from 2—15% nonvolatile material. Some flowers or resinoids obtained by solvent extraction often contain only a small portion of volatile oil, but nevertheless are called essential oils. Several oils are dry-distiUed and also contain a limited amount of volatiles nonetheless they also are labeled essential oils, eg, labdanum oil and balsam oil Pern. The yield of essential oils from plants varies widely. Eor example, nutmegs yield 10—12 wt % of oil, whereas onions yield less than 0.1% after enzymatic development. 

In 1993, the United States imported nearly 22 x 10 kg of essential oils at a total value of almost 190 x 10 , an increase over 1992 of ca 2.3 X 10 kg and 935,000. Table 1 fists the quantities and values of 35 imported essential oils. The United States exports seven principal essential oils orange, lemon, peppermint, spearmint, cedarwood, clove, and nutmeg. The latter two are not grown in the United States but are imported as dried spice, processed for oil, and then exported. 

Mondello et al. (54) have developed some applications of on-line HPLC-HRGC and HPLC-HRGC/MS in the analysis of citrus essential oils. In particular, they used LC-GC to determine the enantiomeric ratios of monoterpene alcohols in lemon, mandarin, bitter orange and sweet orange oils. LC-GC/MS was used to study the composition of the most common citrus peel, citrus leaf (petitgrain) and flower (neroli) oils. The oils were separated into two fractions, i.e. mono- and sesquiterpene... 

Pickles aud Karl have made an examination of the essential oil distilled from the fruit of this plant which is alari known as An /mum mcilivm. They find that the oil resides almost entirely in the seeds. By distilling the fruits with steam, aliout 1 per cent, of a pale yellow oil, having an odour cecalliug those of lemon aud eucalyptus, was obtained. The Oil has the following chanteters —... 

Limonene occurs freely in nature, forming the greater part of oils of lemon and orange, and found to a large extent in caraway, dill, bergamot, and many other essential oils. 

This sesquiterpene is a monocyclic compound, first isolated from the essential oil of Bisabol myrrh by Tucholka. It was found in oil of limes, and described by Burgess under the name limene. It occurs in several other essential oils. When separated by fractional distillation from lemon oil, Gildemeister and Mullerfound it to have the following characters —... 

Linalol is found very widely distributed in essential oils. It forms the principal constituent, in the free state, of oil of linaloe, and the chief odorous constituent, in the form of esters, in bergamot and lavender oils. It is also found in ylang-ylang, rose, champaca leaf, cinnamon, petit-grain, spike, geranium, lemon, spearmint, and numerous. other essential oils. 

The former is the more probable constitution. Citral as found in commerce, is probably almost invariably a mixture of the two isomers, which are very similar in their general characters. It occurs to a considerable extent in various essential oils, being the principal constituent of lemon-grass oil, and of the oil of Backhmisia citriodora, and occurring to the extent of about 4 to (i irer cent, in lemon oil, which owes its characteristic flavour to this aldehyde. 

Methyl-heptenone, CgH, 0, occurs in various essential oils, especially lemon-grass oil, in which it is associated with, and difi cult to separate from, the aldehyde citral. 

Caproic acid.CjHjj. COOH, has been found in lemon-grass, palmarosa, and several other essential oils. It is a liquid having the following characters —... 

Both recycled and non-recycled essential oils met the standards for specific gravity, angular rotation and refractive index of the Food Chemicals Codex [22] and United States Pharmacopeia [23] for cold-pressed lemon peel oil. Results of gas chromatography analysis show the same compounds and levels in both systems, specially for the oxygenated compounds as citral (neral and geranial). Therefore, recycling the aqueous discharges to the extractor does not cause undesirable modifications. 

The enantiomeric differentiation of linalool is useful in the quality control of essential oils and oleoresins, as it was found to provide an important indication of the authenticity of many herbs and spices. The enantiomeric composition of linalool has been determined in many essential oils, including basil, bergamot, rosemary, lavandin, lavender, balm, coriander, mace. Pelargonium, rose, Cymbopogon, lemon, mandarin, Osman-thus, davana, jasmine, Lippia alba and orange, as well as in many fruit... 

Linalyl acetate is the principal constituent of the essential oils of bergamot, clary sage, lavender and lavandin. It is also present in the essential oils of Salvia officinalis, petitgrain, sassafras, neroli, lemon, lime, a few Mentha species and others. 

The first fully comprehensive coupling of NP and RP, where the previously described difficulties related to solvents immiscibility were overcome, was developed by Dugo et al. and applied to the analyses of oxygen heterocyclic components of lemon essential oils [22], Based on the configuration described in this work, other applications were developed for the analysis of carotenoids in citrus samples [48], citrus fruit extracts [29], pharmaceutical products [29], and triglycerides in fats and... 

Fig. 15.8 Conventional GC (a) and fast GC (b) chromatograms of a lemon essential oil [77]. Copyright (2003) American Chemical Society...

Essential oil Steam distillation Spearmint oil, lemon oil, pepper oil... 

Main constituent of citrus fruit peels oils, common in many other essential oils. (+)-limonene orange, lemon, grape oils ... 

Monoterpenes, 10-carbon-containing terpenoids, are composed of two isoprene units, and found abundantly in plants, e.g. (+)-limonene from lemon oil, and (—)-linalool from rose oil. Many monoterpenes are the constituents of plant volatile oils or essential oils. These compounds are particularly important as flavouring agents in pharmaceutical, confectionery and perfume products. However, a number of monoterpenes show various types of bioactivity and are used in medicinal preparations. For example, camphor is used in liniments against rheumatic pain, menthol is used in ointments and liniments as a remedy against itching, bitter-orange peel is used as an aromatic bitter tonic and as a remedy for poor appetite and thymol and carvacrol are used in bactericidal preparations. 

In addition to its role as an intermediate in cholesterol biosynthesis, isopentenyl pyrophosphate is the activated precursor of a huge array of biomolecules with diverse biological roles (Fig. 21-48). They include vitamins A, E, and K plant pigments such as carotene and the phytol chain of chlorophyll natural rubber many essential oils (such as the fragrant principles of lemon oil, eucalyptus, and musk) insect juvenile hormone, which controls metamorphosis dolichols, which serve as lipid-soluble carriers in complex polysaccharide synthesis and ubiquinone and plastoquinone, electron carriers in mitochondria and chloroplasts. Collectively, these molecules are called isoprenoids. More than... 

By Expression.—This method is adapted only for those substances which are very rich in essential oil as examples, the rinds of the lemon, orange, citron, and some other fruits. The chief implement is a powerful press. The material Is either inclosed in hair bags, or a tinned metal box—Fig, 391— FJs.asi, resting upon the bottom of the press. The box must be lined with a perforated cylinder—Fig, 392—having perpendicular ribs ou the exterior Circumference. These latter, projecting against the inner sides of the box, form Fig.eess. channels by which the flow of... 

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