Chapter

Citrus Oils and Essences

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Abstract

Citrus fruits are among the most popular fruits and have a long history of production and use. However, within the past century, industrial technologies have began to develop in order to convert citrus fruits into commercial products. Citrus has proven to be a very good option for oil and essence production. Citrus peel oils are of a very complex composition and are contained in oval, balloon-shaped oil sacs, or vesicles locate in the outer rind, or flavedo, of the fruit The oil is usually extracted by mechanical separation or hydrodistillation.Citrus seeds are regarded as a new source of oil. The seed oil is recovered from the seeds by crushing and solvent extraction. Citrus essences are distilled aqueous solutions of more volatile components from the corresponding citrus juices.Citrus peel oils are used widely in beverages, cosmetics, pharmaceuticals, and the perfumery industry. Seed oils are used in cooking and the treatment of leather and textiles. Quality and freshness are the major considerations pertaining to their value and applications. Most of the qualitative changes in citrus peel oil occur during storage.Storage changes and chemical composition of the citrus oils are described. Despite increasing application of these oils, certain challenges related to potential health-damaging properties and contamination exist. These health and safety factors are discussed.

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... Indeed, annual citrus production has doubled over the last 5 years and is now estimated at over 100 million tons,inducing a dramatic amount of wastes. Citrus by-products (peels) have interested several fields (agro-industry, cosmetics, flavoring, pharmaceutical…) in which their uses are diverse such as essence and fragrances [20], aromatherapy [21] and food flavoring [22]. ...
... . / (20) After the pressure drop stage (e) and during the vacuum stage (f), the deep total pressure in the porous mediumis mainly due to the water and essential oil vapor. Theinternal gas transfer is carried out in a homogeneous and isotropic medium. ...
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To entirely recover and value orange peels by extracting both essential oils and antioxidant compounds, hydrodistillation and standard solvent extraction are usually used. These treatments are known as long, fastidious,and energy-consuming processes mainly because of a low diffusivity coupled with a low starting accessibility. Various innovative processes were recently proposed, studied and optimized. They could have their own advantages. By analyzing the fundamental aspects of different processes, it was possible to recognize the limiting phenomena.Therefor, combining adequate innovative processes intensified the whole operation.This will increase heat and mass transfers; both process performance and extract quality could be dramatically improved.DIC (Détente InstantanéeContrôlée), instant controlled pressure-drop treatment enhances autovaporization, which results in an expansion of the sample. The autovaporization enables a direct extraction of essential oils simultaneously triggering expansion, which enhances the availability of some molecules and also increases solvent diffusivity within the plant matrix. Ultrasound extraction process is fast in comparison with standard methods, thanks to a greater contact surface area between solid and liquid phase. It was possible to compare the effect of ultrasound-assisted extraction to standard solvent extraction in terms of fundamental aspects, highlighted with a former experimental study. Fundamentals enabled the study and comprehension of the extraction modelling.As an example, orange peel extraction has been studied. In order to achieve innovative extraction, we combined and associated these two techniques. We carry outthe treatment by DIC to extract the essential oils and at the same time to obtain a textured vegetal material. Followed by ultrasound assisted solvent extraction, a great intensification of antioxidants extraction is generated. It was possible to compare the effect of ultrasound assisted extraction to standard solvent extraction both achieved on dried orange peels as raw material and DIC treated material. Combining DIC to ultrasounds enabled enhancing yields and extraction kinetics of antioxidant.
... In treating leather and textiles, crude citrus oils are often used for the preparation of soaps and detergents. Some developing countries have regarded it as a new source of edible oil where oil shortage exists (Shahidi et al., 2005). Citrus molasses is an important byproduct of citrus juice extraction. ...
Chapter
Agro-industrial waste wreaks havoc due to its inefficient dumping and excessive burning, causing huge environmental pollution (Afsar and Naser, 2008). Therefore, there has been an escalating interest on how to utilize agro-industrial waste products for human health, animal feed (Maneerat et al., 2015), and other potential uses. Agriculturalists and food technologists who previously treated these crop and food residues as trash and discarded them into the encompassing environs have now understood the importance of agro-based byproducts and have changed their minds. Now, strategies are being planned to utilize these useful by-products for ruminant feeds, poultry feed, and most importantly for human health.
... The initially formed peroxides, as well as the secondary oxidation products aldehydes, ketones, epoxides and others are responsible for undesirable aromas, the loss of essential amino acids and lipid-soluble vitamins and other negative biological effects. [1] Antioxidants are compounds which delay or prevent oxidation process. The most frequently used antioxidant compounds are those of synthetic origin. ...
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... [6] The genus Citrus is from the Rutaceae family and is a suitable candidate for essential oil extraction. This genus comprises eight main species [10] , among which sour orange (Citrus aurantium L.) is an important species having essential oil. [11] Sour orange natively belongs to South-east Asia, which then spread westward. ...
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Effects of UV and X-ray treatments on oxidative stability of soybean oil were evaluated during accelerated storage. Furthermore, antioxidant activity of neroli oil incorporated into soybean oil was compared with those of BHT and β-carotene. UV and X-ray treated samples had significantly higher peroxide (105.00 and 191.99 meq O2/kg, respectively), anisidine (62.30 and 153.80 mg/kg, respectively), and Totox values (272.3 and 453.43, respectively) than non-irradiated samples (75.74 meq O2/kg, 26.50 mg/kg, and 177.98, respectively). The X-ray radiation accelerated the oxidation of soybean oil more significantly than UV radiation did. This could be due to the fact that X-ray radiation has a higher energy content. In addition, neroli oil proved its antioxidant activity in soybean oil. Nonetheless, neroli oil had a lower antioxidant activity than BHT – a chemical agent – while β-carotene was neither antioxidant nor pro-oxidant. In conclusion, neroli oil can improve the oxidative stability of irradiated and non-irradiated soybean oil.
... Essential oils of Citrus are commercially used for flavoring foods, beverages, perfumes, cosmetics and medicines (Babazadeh-Darjazi, 2009). In addition, recent studies have identified insecticidal, antimicrobial, antioxidative and antitumor properties for Citrus peel oils (Shahidi & Zhong, 2005). ...
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The peel components and juice quality of three mandarin hybrids were investigated in this study. Peel components were extracted using the cold-press method and analyzed using GC-FID and GC-MS. Total soluble solids, total acid, pH value, ascorbic acid as well as density were determined in juice obtained from mandarin hybrids. Twenty-six, thirty-five and nineteen peel components were identified in Fortune, Robinson and Osceola respectively including: aldehydes, alcohols, esters, monoterpenes, sesquiterpenes and other components. The major components were limonene, γ-terpinene, (E)-β-ocimene, β-myrcene, sabinene, linalool and α-Pinene. Among the three scions examined, Fortune showed the highest content of aldehydes and Robinson showed the highest content of TSS. This study shows that scion has a profound influence on aldehyd and TSS that are important to quality improvement.
Article
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Chapter
The challenge of the future is the adequate production of food for an ever increasing population utilizing an ever decreasing area of arable land and the keeping of food production in harmony with the environment. Modern processing techniques produce significant amounts of by-products that are now being used as fertilizer or just dumped creating pollution problems. As the cost for handling waste increases, a point may be reached where it becomes economically feasible to recover from the waste potentially edible oils and protein. Often the wastes that still contain potentially recoverable oil and protein are produced in areas where these food components are in short supply. The recovery of edible oil from by-products of food processing increases the source of this edible commodity and turns potential pollutants, which may be costly to control, into useful cash producing commodities.
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Peel oils of the Murcott (Honey) tangerine were investigated analytically. The comparison of commercial Brazilian Murcott oils with other available mandarin oil varieties, as well as the analytical distinction to orange oils, constituted the main emphasis of the present work. GC analysis permitted the identification of 88 components in the volatile range. As in all citrus oils, limonene was the main constituent. Components, which are characteristic for many mandarin oils, such as γ-terpinene, N-methyl-methylanthranilate or thymol, did not occur in the Murcott variety. Both the volatile composition of Murcott oils and the enantiomeric distribution of α-pinene, limonene and linalool, pointed to a close relationship to orange, whereas cliiral analysis of citronellal permitted the analytical distinction to orange. On the other hand, the enantiomeric purity of (+)-α-pinene served as a distinctive feature to other mandarin varieties. Murcott oils were characterized by a mandarin-typical UV pattern of the non-volatile constituents when subjected to HPLC separation. Six polymethoxylated flavones were identified, quantitatively tangeretin constituted the most significant representative of this compound class. In sensorial terms, Murcott tangerine peel oil is described as aldehydic, flowery and resembling orange-tangerine.
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Article
The analysis of citrus essential oils for their content of polymethoxylated flavones (PMFs) using packed column supercritical fluid chromatography (SFC) is described. Samples of sweet orange and mandarin oil were quantitatively analyzed and the resulting flavone levels compared to the values obtained using liquid chromatography. In addition, milligram quantities of all six individual flavone compounds were isolated from a sample of sweet orange oil. Flavone retention in SFC is explained on the basis of substituent dipolarity. Dipoles were calculated using molecular modeling techniques, and the effects of substituent positions or neighboring dipoles were investigated. It is postulated that steric hindrance plays a role in the retention mechanism. Keywords: Polymethoxylated flavones; sweet orange oil; mandarin oil; SFC
Article
Ten polymethoxylated flavonoids were isolated and characterized from cold pressed tangerine oil solids; they are 5,6,7,3‘,4‘-pentamethoxyflavone (sinensetin) (I); 7-hydroxy-3,5,6,3‘,4‘-pentamethoxyflavone (II); 5-hydroxy-6,7,8,3‘,4‘-pentamethoxyflavone (III); 5,6,7,8,3‘,4‘-hexamethoxyflavone (nobiletin) (IV); 5,6,7,8,4‘-pentamethoxyflavone (tangeretin) (V); 5,7,8,4‘-tetramethoxyflavone (tetra-O-methylisoscutellarein) (VI); 7-hydroxy-3,5,6,8,3‘,4‘-hexamethoxyflavone (VII); 5,6,7,4‘-tetramethoxyflavone (tetra-O-methylisoscutellarein) (VIII); 3,5,6,7,8,3‘,4‘-heptamethoxyflavone (IX); and 5,7,8,3‘,4‘-pentamethoxyflavone (X). Structures of the compounds were elucidated on the basis of spectroscopic methods and chemical data. Compounds II and VII are novel natural products; compounds IV, V, and VIII have been reported with significant activity against various strains of carcinoma cells; and compounds I and IV decrease erythrocyte aggregation and sedimentation in vitro. A biological activity screen of other compounds is in progress. Keywords: Polymethoxylated flavones; antitumor activity; Citrus; tangerine oils; Dancy tangerine
Article
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Article
Two volatile fractions prepared from Citrus temple juice distillate, aqueous essence and essence oil, were analyzed by gas chromatography and mass spectrometry. Twenty-eight components of aqueous essence and thirty-eight components of essence oil were identified. Two essence oil components, γ-cadinene and nootkatol, had not been reported earlier as citrus components. The influence of mandarin parentage in Citrus temple explained many differences in composition between aqueous essences and essence oils from this hybrid compared to those from orange varieties normally used in preparing orange juice products.
Article
Thirty-three constituents accounting for 96.64% of total volatiles of Thompson navel orange peel oils have been identified and quantified in a single GC capillary run. The quantitation was performed using appropriate response factors and identification using pure samples and GC-mass spectrometry. After identification, experiments were carried out to test qualitative and quantitative differences on essential oils of peel of Thompson navel oranges stored under different cold-storage conditions. During storage at a constant temperature of 6-degrees-C and at a cyclic temperature of 6 days at 2-degrees-C plus 1 day at 14-degrees-C, an increase of volatile compounds (acetaldehyde, formic acid, formaldehyde, and acetic acid) and a decrease of limonene content were observed. The cold-storage trials with Thompson navel oranges showed that the minor variations in the content of essential oils were obtained using cyclic temperature storage with short cycles: 6 days at 6-degrees-C plus 1 day at 14-degrees-C and 18 days at 6-degrees-C plus 7 days at 14-degrees-C.
Article
Fractional extraction with supercritical carbon dioxide was studied for the preparation of terpeneless citrus oil using a 9 mm i.d. and 1.0 m long packed column with an axial temperature gradient of 0-20 K. The separation of citrus oil model mixture, which consists of limonene, linalool, and citral, was investigated at various column temperature distributions of 313-333 K, pressures of 8.8-11.8 MPa, and CO2 flow rates of 0.091-0.512 g/s. The selective separation was performed due to the internal reflux in the column induced by an axial temperature gradient. A little increase in pressure or CO2 flow rate accelerated the extraction rate without decreasing the selectivity. Raw orange oil was processed successfully at a temperature gradient of 20 K, from 313 K at the bottom to 333 K at the top of the column, and a pressure of 8.8 MPa.
Article
The chemical composition and minerals content of citrus seeds and its flours, the characteristics and structure of citrus seed oils as well as nutritional properties were studied. The citrus seeds and its flours were rich in oil and protein, respectively. Both citrus seeds and flours proved to be a good source for minerals K, Ca, P, Na, Fe and Mg. The flours of citrus seeds were rich in leucine, valine, total aromatic and total sulfur amino acids compared to FAO/WHO reference. Refractive index, specific gravity, melting point, colour and viscosity of citrus seeds oils differed slightly. Citrus seed oils had eight classes, according to the results of thin-layer chromatogram. Triglycerides were the major oil class in all samples. The citrus seeds oil samples contained eight fatty acids while linoleic, oleic and palmitic acids were major acids. Some antinutritional compounds were detected in the flours. The results revealed that, glucosides, stachyose, raffinose, trypsin inhibitor, phytic acid and tannins were present in all citrus seeds flours. The data established that all flours were completely free from any agglutination activity. The biological values, true and apparent digestibility of mandarin seed protein were the lowest among all citrus seeds proteins by all measurements except the PER equations.
Article
The most intense aroma volatiles of extracted and distilled oils from the peels of key lime (Citrus aurantifolia Swingle) were identified using gas chromatography–olfactometry (GC–O) and gas chromatography–mass spectrometry (GC–MS). Over 50 odour-active volatiles were detected in the extracted oil, and over 60 in the distilled oil. Geranial, neral and linalool were found to dominate the lime oil aroma in both oils, which accounted for their fresh, floral citrus-like character. Many simple aldehydes contributed to the aroma of the extracted oil, giving it a characteristic lime tone. The distilled oil contained many new odourants, resulting from the acid-catalysed distillation, which imparted woody, musty, spicy and balsamic notes to its aroma. These are C10 alcohols and ethers and many sesquiterpenes, most of which possess lower odour activity and contribute to the more intense piney aroma of the distilled oil. 7-Methoxycoumarin was found to be one of the more intense odourants in the extracted oil. Caryophyllene oxide and humulene oxide II were found to be major odourants in the distilled oil; their intensities varied with the method of analysis of the oil. They contribute a sawdust-like and skunky odour, respectively, to the distilled lime oil. Many sesquiterpenes were found to possess some odour activity. Copyright © 2003 John Wiley & Sons, Ltd.
Article
Seeds from five varieties of Tunisian Citrus fruits, namely blood orange (Citrus sinensis), sweet orange (Citrus sinensis), lemon (Citrus limon L.), bergamot (Citrus bergamia) and bitter orange (Citrus aurantium), were examined for their composition of lipid classes and fatty acids. In addition, the oil yield, total fatty acids, palmitic, oleic and linoleic acids were determined. Petroleum ether-extracted oils of these Citrus seeds amounted to more than 78% in the case of lemon seeds. The Citrus seed oils had three lipid classes as determined by thin-layer chromatography. Triacylglycerols were the major oil class in all varieties. Gas chromatographic analyses revealed that the main fatty acids were palmitic, oleic and linoleic acids.
Chapter
IntroductionIsolation of natural fragrance and flavor concentrates Essential oilsExtractsSurvey of natural raw materials Essential oilsExtracts
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Mesquite gum solutions (30% w/v) were used to emulsify orange peel oil in an oil-gum solids ratio of 0.25. Emulsions were spray dried in laboratory scale equipment. The powders were stored in aw(s) from 0.108 to 0.743 at 35 °C. Quantitative analysis of limonene oxide indicated that the sample at 0.628 showed a very good stability against oxidation after thirty d, without caking and stickiness occurring. At this water activity the system was within rubbery state, and the moisture content corresponded to that of the minimum integral entropy.
Article
The compositions of Vietnamese pummelo (Citrus grandis Osbeck), orange (C. sinensis Osbeck), tangerine (C. reticulata Blanco var. tangerine) and lime (C. limonia Osbeck) peel oil samples have been investigated by GC and GC–MS. The essential oils were extracted by the cold-pressing method. Hydrocarbons, followed by aldehydes and alcohols, were the most abundant compounds in all four kinds of samples. Their percentages, respectively, were >98.7%, >97.6%, >98.6% and >95.4% in hydrocarbons; >0.3%, 0.4%, >0.3% and 1.1% in total aldehydes; 0.2%, 0.5%, 0.4% and 0.7% in alcohols. In Vietnamese pummelo oil, γ-terpinene was not detected, while terpinolene was detected in small amounts and nootkatone only at a level of <0.05%. Orange oil composition was comparable to that of other sweet orange oils. δ-3-Carene was detected at a level of 0.1%. Tangerine oil is easily distinguished from other citrus oils by its content of various aliphatic aldehydes. Lime oil presented a very different composition from the other oils studied. Its limonene content was substantially lower than that of pummelo, orange and tangerine oils, whereas γ-terpinene, β-pinene and α-pinene occurred in higher proportions, moreover, the sesquiterpene hydrocarbon fraction of this oil is qualitatively more complex and quantitatively more abundant than in the other oils. Copyright © 2002 John Wiley & Sons, Ltd.
Article
In an extract of the peel from clementines, prepared by solvent extraction, 42 odour-active compounds were detected by application of an aroma extract dilution analysis and subsequently identified by using the respective reference odorants. Among them, by far the highest flavour dilution factors were determined for the flowery smelling linalool, the fatty smelling (E,E)-deca-2,4-dienal and the winelactone eliciting a sweet odour quality. These were followed by &#33-pinene, myrcene and octanal with pinetree-like, geranium leaf-like and citrus-like aromas. Among the 30 odour-active compounds identified, 11 aroma compounds are reported here for the first time as important contributors to clementine peel aroma, e.g. winelactone, (E,E)-nona-2,4-dienal, carvone, (Z)-hex-3-enal or tr-4,5-epoxy-(E)-dec-2-enal.
Article
Seeds of the citrus fruits orange, mandarin, lime and grapefruit were analyzed. Petroleum ether-extracted oils of such seeds amounted to more than 40% of each. Physical and chemical properties of the extracted oils are presented. Samples of the extracted oils were saponified and the unsaponifiables and fatty acid fractions isolated. The isolated unsaponifiables and fatty acids were analyzed by GLC. GLC analysis of the unsaponifiables revealed compositional patterns differ-ent in number, type and relative concentration of fractions according to type of citrus seed oil, depending on the solvent system used for oil extraction and unsaponifiable matter isolation. The compositional patterns of the unsaponifiables were similar to that of cottonseed oil. Mandarin and grapefruit oils are free of cholesterol. The data demonstrate that the fatty acid compositional patterns of the oils differ; Mandarin seed oil contains the largest number of fatty acids, and grapefruit seed oil contains the lowest. The total amounts of volatile fatty acids in these oils are generally higher than those of other edible oils. Lime seed oil is similar, in the degree of unsaturation, to soybean oil. The orange oil pattern is similar to cottonseed oil. The amount of total essential fatty acids in lime seed oil is the highest of the oils studied.
Article
Refined and bleached fats and oils can be analyzed directly by high-temperature glass capillary column gas chromatography after derivatization of the fatty acids, mono- and diglycerides with BSTFA [(N,O)-bis(trimethyl silyl) trifluoroacetamide]. The intact glycerides are separated on the basis of volatility to provide characteristic carbon number profiles (CNP). Quantitative information on mono-, di- and triglycerides, as well as free fatty acids, is obtained from a single, rapid separation. Profile values are reported for 13 different processed fats and oils. The analysis performed in the split-injection mode maintains column integrity after numerous separations, while producing acceptable relative standard deviations.
Article
The effectiveness of natural essential oils eucalyptus (Eucalyptus globulus), tea tree (Melaleuca alternifolia), melisa (Melissa officinalis), roomer (Rosmarinus officinalis), clove (Syzygium aromaticum) and lemon (Citrus limonum) to reduce peroxidase activity of organic leafy vegetables extracts was evaluated. Three oil concentrations at the minimum inhibitory concentration (MIC, 2×MIC and 4×MIC) of each natural essential oils were used. Crude vegetable extracts of Swiss chard, spinach, lettuce, butter lettuce and cabbage were the source of peroxidase activity. The effectiveness of the essential oils as natural antioxidants varied with the enzyme sources. At the MIC, clove, rosemary, lemon, melisa and tea tree had the high antioxidant properties being clove more effective than the other oils.
Article
A new NIRS method is introduced for the determination of valuable components in various citrus oils. Spectra of grapefruit, orange, mandarin, lemon and lime oils in the range from 1100 to 2500 nm have been registered. Applying principal component analysis to the spectral data a good separation of the different fruit oil types can be achieved. The application of multivariate statistics in conjunction with analytical reference data leads to good NIR calibration results. For the main components (e.g. limonene, γ-terpinene, sabinene) and general chemical–physical parameters (e.g. optical rotation value, aldehyde content) standard errors are in the range of the applied reference method. The multiple coefficients of determination (R2) for components with an amount of more than 1.5% are generally >0.95. Furthermore reliable in-process methods for the determination of the individual nootkatone and aldehyde contents during the isolation and purification process from grapefruit and orange oil are presented.
Article
Generally on the gas chromatogram of a volatile essential oil, terpenes, oxygenated compounds and sesquiterpenes appear. With temperature programming, it was shown that some non-volatiles are present with the volatiles. They are simple coumarin (2H-1-benzopyran-2-one) derivatives such as citropten (5,7-dimethoxycoumarin) and furocoumarins (psoralen, 7H-furo[3,2-g][1]benzopyran-7-one) such as bergapten (5-methoxypsoralen), some of which are phototoxic. Terpeneless oils are used in perfumes and cosmetics, so it is important to be able to establish rapidly if they contain phototoxic compounds.
Article
This study examined the effect of volatile components of citrus fruit essential oils on P. digitatum and P. italicum growth. The hydrodistilled essential oils of orange (Citrus sinensis cvv. “Washington navel”, “Sanguinello”, “Tarocco”, “Moro”, “Valencia late”, and “Ovale”), bitter (sour) orange (C. aurantium), mandarin (C. deliciosa cv. “Avana”), grapefruit (C. paradisi cvv. “Marsh seedless” and “Red Blush”), citrange (C. sinensis x Poncirus trifoliata cvv. “Carrizo” and “Troyer”), and lemon (C. limon cv. “Femminello”, collected in three periods), were characterized by a combination of GC and GC/MS analyses. The antifungal efficacy of the oils was then examined at progressively reduced rates. Findings showed a positive correlation between monoterpenes other than limonene and sesquiterpene content of the oils and the pathogen fungi inhibition. The best results were shown by the citrange oils, whose chemical composition is reported for the first time, and lemon. Furthermore P. digitatum was found to be more sensitive to the inhibitory action of the oils.
Article
Twenty-eight kinds of citrus essential oils and their components were studied for inhibitory effects on the formation of N-nitrosodimethylamine (NDMA). The reaction mixture consisted of dimethylamine and sodium nitrite adjusted at pH 3.6, in addition to essential oils and an emulsifying agent. The quantification was determined by high-performance liquid chromatography monitored at 220 nm. All of the essential oils inhibited the formation of NDMA in the range of 20-85%. The oils of ujukitsu (Citrus ujukitsu Hort. ex Shirai), yuzu (C. junos Tanaka), mochiyu (C. inflata Hort. ex Tanaka), and ponkan (C. reticulata Blanco cv. F-2426) inhibited the formation of NDMA much more effectively than other citrus oils. The inhibitory proportions of components of citrus essential oils such as myrcene, alpha-terpinene, and terpinolene were as high as 80%.
Article
Oils were extracted from the peels of 8 different fruits and tested for toxicity to serveral species of stored-product insects. Topical applications showed that lyophilized oils from lemon, grapefruit, lime, kumquat, and tangerine were highly toxic to the cowpea weevil, Callosobruchus maculatus (F.), and that all 8 oils were moderately toxic to the rice weevil, Sitophilus oryzae (L.). TLC analyses and topical applications to the insects showed that the active component of the lemon peel was not a residue of the insecticides and acaricides generally used as prehavest treatments, or of the fungicides used as postharvest treatments.
Article
The analysis of bitter orange and grapefruit essential oils (non-volatile fraction) was carried out by HPLC in normal- and reversed-phase mode with UV detection. These oils were compared with the sweet orange and mandarin essential oils, analyzed previously. For the identification of chromatographic peaks, fractionation by RP-HPLC was carried out. The purified fractions were analyzed by GC-MS and LC-MS. Some new compounds were found, together with many others already identified in different citrus essential oils.
Article
Peel oils of lemon, grapefruit and navel orange were tested for insecticidal activities against larvae and adults of Culex pipiens and Musca domestica. Lemon peel oil was the most effective against larvae and adults of C. pipiens. Grapefruit peel oil was more toxic to adults of M. domestica while lemon oil, was more toxic Musca larvae. On the other hand, the orange peel oil was the least effective against larvae and adults of both species. The toxicity of oils applied to larval stages was extended to pupal and adult stages. C. pipiens adults appeared with paralyzed legs, while M domestica adults appeared normal. The weights of pupae treated as larvae were generally less than that of the control. All oils produced deleterious effects on fecundity of survivors of sublethal doses. The effect was obviously recorded in treated adults. Treatment of Culex & Musca with oils caused serious latent effect.
Article
Monoterpenes are nonnutritive dietary components found in the essential oils of citrus fruits and other plants. A number of these dietary monoterpenes have antitumor activity. For example, d-limonene, which comprises >90% of orange peel oil, has chemopreventive activity against rodent mammary, skin, liver, lung and forestomach cancers. Similarly, other dietary monoterpenes have chemopreventive activity against rat mammary, lung and forestomach cancers when fed during the initiation phase. In addition, perillyl alcohol has promotion phase chemopreventive activity against rat liver cancer, and geraniol has in vivo antitumor activity against murine leukemia cells. Perillyl alcohol and d-limonene also have chemotherapeutic activity against rodent mammary and pancreatic tumors. As a result, their cancer chemotherapeutic activities are under evaluation in Phase I clinical trials. Several mechanisms of action may account for the antitumor activities of monoterpenes. The blocking chemopreventive effects of limonene and other monoterpenes during the initiation phase of mammary carcinogenesis are likely due to the induction of Phase II carcinogen-metabolizing enzymes, resulting in carcinogen detoxification. The post-initiation phase, tumor suppressive chemopreventive activity of monoterpenes may be due to the induction of apoptosis and/or to inhibition of the post-translational isoprenylation of cell growth-regulating proteins. Chemotherapy of chemically induced mammary tumors with monoterpenes results in tumor redifferentiation concomitant with increased expression of the mannose-6-phosphate/insulin-like growth factor II receptor and transforming growth factor beta1. Thus, monoterpenes would appear to act through multiple mechanisms in the chemoprevention and chemotherapy of cancer.
Article
Contamination by phthalate esters of Sicilian and Calabrian citrus essential oils, produced in the crop years 1994-1996, was investigated using a GC-MS system with direct injection of the samples. A total of 35 lemon oils, 31 orange oils, and 21 mandarin oils were analyzed. Diisobutyl phthalate and/or bis(2-ethylhexyl) phthalate were found in almost all samples, while di-n-butyl phthalate was present in 8. Concentrations up to a maximum of 62 ppm were found for diisobutyl phthalate and up to a maximum of 29.9 ppm for bis(2-ethylhexyl) phthalate.
Article
The effect of wax application, storage temperature (4 or 21 degrees C), and storage time (14 or 28 days after wax application) on grapefruit gland oil composition was examined by capillary gas chromatography. Wax application decreases nonanal and nootkatone levels. beta-Pinene, alpha-phellandrene, 3-carene, ocimene, octanol, trans-linalool oxide, and cis-p-mentha-2,8-dien-1-ol levels increase, but limonene levels decrease, with temperature. Levels of alpha-pinene, limonene, linalool, citronellal, alpha-terpineol, neral, dodecanal, and alpha-humulene decrease with time. Levels of alpha-phellandrene, 3-carene, ocimene, and trans-linalool oxide increase with time. No compound level was affected by the interactive action of temperature and wax application, suggesting that these two factors cause grapefruit oil gland collapse (postharvest pitting) through means other than changing gland oil composition. Compounds that are toxic to the Caribbean fruit fly (alpha-pinene, limonene, alpha-terpineol, and some aldehydes) decrease with time, thus suggesting grapefruit becomes increasingly susceptible to the fly during storage.
Article
It is generally accepted that lipid peroxides play an important role in the pathogenesis of free radical-induced cellular injury and that antioxidants such as glutathione, ascorbic acid and alpha-tocopherol are vital in cellular defense against endogenous and exogenous oxidants. The purpose of this study was to investigate the effectiveness of a natural compound, derived from lemon oil extract, in controlling free radical-induced lipid peroxidation and tissue damage in the skin. We provide evidence that a compound isolated from lemon oil, which we have called Lem1, is endowed with a strong antioxidant activity and that it is capable of inhibiting free radical-mediated reactions, evaluated by both in vitro and in vivo biochemical systems. The present study aims to give a preclinical perspective on the biochemical properties of Lem1, a natural compound, as well as to provide a better understanding of the endogenous antioxidant potential of skin and the real validity of a natural antioxidant biotechnology in the antiaging management of the skin.
Article
Atmospheric pollutants are an important source of oxidative and nitrosative stress both to terrestrial plants and to animals. Skin, which has a highly differentiated and certainly complex organizational structure, is particularly vulnerable to free radical damage because of its contact with oxygen and with other environmental stimuli. Fruit and vegetables contain several classes of compounds that when ingested can potentially contribute to antioxidant defenses. In the present study we employed a novel gas chromatographic method to assess the antioxidant properties of a natural compound isolated from lemon oil, which we have called Lem1. We provide experimental evidence that Lem1 is endowed with a strong antioxidant activity and that it is capable of inhibiting free radical-mediated reactions, as evaluated in vitro and in vivo. The present study extends our previous findings and demonstrates that topical application of Lem1 in healthy volunteers significantly increases the antioxidative potential of skin biosurface, thus highlighting the effectiveness of a natural antioxidant biotechnology in the antiaging management of skin.
Article
Organochlorine pesticide contamination in 148 lemon essential oils, 123 sweet orange oils, 121 mandarin oils, and 147 bergamot oils produced in Italy in the years 1991-1996 was studied by HRGC-ECD. Confirmation analyses were carried out by GC-MS. Tetradifon, dicofol and its decomposition product 4,4'-dichlorobenzophenone were found. Over the course of the study dicofol and tetradifon residues steadily decreased; the percentage of contaminated samples reflects this course and decreases considerably from 1991 to 1996.
Article
Auraptene quantities in Tanaka's 77 Citrus species (including 14 varieties and cultivars), 5 Fortunella species, one Poncirus species, 27 hybrids between Citrus species, and 51 intergeneric hybrids between Citrus and Poncirus have been evaluated. The genus Citrus has been divided into eight groups. Auraptene is found in all of the species of Cephalocitrus group, a part of the species of Aurantium group, and most of the species of Osmocitrus group. The Citrus species contain a small amount of auraptene in the juice sacs compared with in the peels except for Henka mikan (C. pseudo-aurantium), Ichang lemon (C. wilsonii), and a Hassaku (C. hassaku)-pummelo hybrid (Okitsu No. 39), which contain large quantities of auraptene in their juice sacs (0.23, 0.52, and 0.14 mg/g, respectively). The Hong Kong wild kumquat (F. hindusii) alone contains auraptene in Fortunella species. All of the Citrus-trifoliate orange (P. trifoliata) hybrids as well as the trifoliate orange contain a large quantity of auraptene in both the peel (16.57-0.51 mg/g) and the juice sac (10.32-0.15 mg/g). These hybrids are almost inedible. The Iyo (C. iyo)-trifoliate orange hybrid (IyP269) is edible and contains auraptene in the peel (1.49 mg/g) and in the juice sac (1.73 mg/g). Citrus fruit products, for example, brand-named grapefruit juice and marmalade, retain about 0. 1 mg and 0.3 mg/100 g of auraptene, respectively.
Article
Antioxidants may be present in foods as endogenous factors or may be added to preserve their lipid components from quality deterioration. Synthetic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG) and tert-butylhydroquinone (TBHQ) are commonly used in food formulations. However, due to safety concerns, interest in natural antioxidants has intensified. To address the demand by consumers, mixed tocopherols, herbal extracts such as those of rosemary and sage, as well as tea extracts have been commercialized for food and nutraceutical applications. An overview of the topic is provided in this article.
Article
This review reports the last decade acquisitions on grapefruit. New coumarins and limonoids were isolated and characterised. The bioavailability of many drugs was tested with grapefruit juice (GJ) coadministration; the inhibition on cytochrome P450 seems due to a synergic action between flavonoids and coumarins. Antimicrobial, antifeeding, insecticidal, and antitumour activities were also reported.
Article
Thirty-four kinds of citrus essential oils and their components were investigated for radical-scavenging activities by the HPLC method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). To examine the oils' relative radical-scavenging activities compared with that of a standard antioxidant, Trolox was employed. All of the essential oils were found to have scavenging effects on DPPH in the range of 17. 7-64.0%. The radical-scavenging activities of 31 kinds of citrus essential oils were comparable with or stronger than that of Trolox (p < 0.05). The oils of Ichang lemon (64.0%, 172.2 mg of Trolox equiv/mL), Tahiti lime (63.2%, 170.2 mg of Trolox equiv/mL), and Eureka lemon (61.8%, 166.2 mg of Trolox equiv/mL) were stronger radical scavengers than other citrus oils. Citrus volatile components such as geraniol (87.7%, 235.9 mg of Trolox equiv/mL), terpinolene (87.4%, 235.2 mg of Trolox equiv/mL), and gamma-terpinene (84.7%, 227.9 mg of Trolox equiv/mL) showed marked scavenging activities on DPPH (p < 0.05).
Article
The composition of the essential oil of Citrus tamurana Hort. ex Tanaka (Hyuganatsu), isolated by the cold-pressing method, was investigated by capillary GC and GC-MS. The effects of harvesting time, degree of freshness, and size of fruits on the composition of Hyuganatsu peel oils were also determined. A total of 126 volatile constituents were confirmed in the Hyuganatsu oils. The Hyuganatsu oils contained hydrocarbons (95.95-96.95%), aldehydes (0.33-0.62%), alcohols (1.91%-2.64%), ketones (0.40-0.62%), esters (0.28-0.39%), oxides (0.04-0.06%), acids (0.01%), and trace amounts of fugenol methyl ether. Monoterpene hydrocarbons were predominant. Limonene (80.35-82.39%), gamma-terpinene (7.71-9.03%), myrcene (2.11-2.28%), linalol (1.37-2.01%), and alpha-pinene (1.17-1.43%) were the most abundant components in Hyuganatsu oils. The principal sesquiterpene hydrocarbon was trans-beta-farnesene (0.60-1.04%), and its content in Hyuganatsu oils was higher than in oils of other citrus fruits. The number of ketones and the content of l-carvone in Hyuganatsu oils were higher than in other citrus oils.
Article
In this study, the contamination by chloroparaffin of Sicilian and Calabrian citrus essential oils, produced in the crop years 1994-1996, was investigated. The analyses were carried out on 102 lemon oils, 98 orange oils, and 96 mandarin oils, using a dual-channel GC-ECD. It was found that 53% of lemon oil, 33% of orange oil, and 38% of mandarin oil samples were contaminated. The mean contamination levels were 7.1 ppm (lemon), 2.5 ppm (orange), and 5.3 ppm (mandarin). The highest concentration of chloroparaffin found was 60 ppm in a lemon oil sample.
Article
Statistical studies using the randomised complete block design with four replicates showed that volatile extracts of two species of orange peel--Citrus sinensis (sweet orange) and Citrus aurantifolia (lime) had insecticidal activity against mosquito, cockroach and housefly. Insecticidal activity was better after 60 min than at 30 min spraying of rooms. Volatile extracts of C. sinensis showed greater insecticidal potency, while the cockroach was the most susceptible to the orange peels among the three insects studied.
Article
The volatile components of Hyuganatsu (Citrus tamurana Hort. ex Tanaka) peel oil, isolated by cold-pressing, were investigated by chemical and sensory analyses. According to chemical analysis by GC and GC-MS, limonene (84.0%) was the most abundant compound, followed by gamma-terpinene (6.9%), myrcene (2.2%), alpha-pinene (1.2%), and linalool (1.0%). Monoterpene hydrocarbons were predominant in Hyuganatsu peel oil. The odor-active volatiles in Hyuganatsu flavor were studied by GC-olfactometry and omission tests. The characteristic flavor was present in the oxygenated fraction. Flavor dilution (FD) factors of the volatile flavor components of the Hyuganatsu cold-pressed oil were determined by aroma extraction dilution analysis (AEDA). Furthermore, relative flavor activity was investigated by means of FD factor and weight percent. Ten kinds of odor compounds having Hyuganatsu-like aroma were detected by AEDA: limonene, linalool, octanol, neral, neryl acetate, tridecanal, trans-carveol, cis-nerolidol, trans,trans-farnesyl acetate, and trans,trans-farnesol. Linalool and octanol were regarded as the most odor-active or key compounds of Hyuganatsu aroma. Diluted solutions of linalool and octanol of approximately 2 ppm gave a fresh and fruity aroma note similar to Hyuganatsu flavor.