Steam distillation-solvent extraction

Essential Oils. Volatile oils from plants are referred to as essential oils. The oils can be obtained through steam distillation, solvent extraction, or separation of the oils from pressed fmit. They consist of oxygenated compounds, terpenes, and sesquiterpenes. The primary flavor components of essential oils are oxygenated compounds. Terpenes contain some flavors but are often removed from the essential oil because they are easily oxidized (causiag off-flavors or odors) and are iasoluble. Essential oils are prepared from fmits, herbs, roots, and spices. 

In liquid-solid extraction (LSE) the analyte is extracted from the solid by a liquid, which is separated by filtration. Numerous extraction processes, representing various types and levels of energy, have been described steam distillation, simultaneous steam distillation-solvent extraction (SDE), passive hot solvent extraction, forced-flow leaching, (automated) Soxh-let extraction, shake-flask method, mechanically agitated reflux extraction, ultrasound-assisted extraction, y -ray-assisted extraction, microwave-assisted extraction (MAE), microwave-enhanced extraction (Soxwave ), microwave-assisted process (MAP ), gas-phase MAE, enhanced fluidity extraction, hot (subcritical) water extraction, supercritical fluid extraction (SFE), supercritical assisted liquid extraction, pressurised hot water extraction, enhanced solvent extraction (ESE ), solu-tion/precipitation, etc. The most successful systems are described in Sections 3.3.3-3.4.6. Other, less frequently... 

Applications Simultaneous steam distillation-solvent extraction has been in use for many years [163]. Steam distillation combined with continuous liquid extraction is an efficient technique for the removal and isolation of volatile compounds in various matrices (environmental,... 

Glausch, A., Blanch, G.P., Schurig, V. (1996). Enantioselective analysis of chiral polychlorinated biphenyls in sediment samples by multidimensional gas chromatography-electron-capture detection after steam distillation-solvent extraction and sulfur removal. J. Chromatogr. A 723, 399 104. 

Richard, J. J., and Junk, G. A., Steam Distillation, Solvent Extraction, and Ion Exchange for Determining Polar Organics in Shale Process Waters. Anal. Chem, 1984. 56 pp. 1625-1628. 

Ahel et al. [11] used steam distillation/solvent extraction and determination by normal phase HPLC for the analysis of NP, NPEOi and NPE02 in freshwater fish. 

Seidel V, Lindner W. 1993. Universal sample enrichment technique for organochlorine pesticides in environmental and biological samples using a redesigned simultaneous steam distillation-solvent extraction apparatus. Anal Cem 65 3677-3683. 

Other odoriferous materials are derived from the leaves and young twigs of Cistus ladaniferus. Cistus oil is obtained by steam distillation solvent extraction yields cistus concrete. Cistus oil, in contrast to labdanum oil, consists mainly of monoterpene hydrocarbons. 

Essences of pink and white fresh guava obtained by direct extraction of flesh juices with dichloromethane revealed that the total amount of Cs aldehydes, alcohols, and acids comprised 20 and 44% of the essence of fresh white and pink guavas, respectively [49]. The flavour of the Costa Rican guava has been described as sweet with strong fruity, woody-spicy, and floral notes [53]. One hundred and seventy-three volatile compounds were isolated by simultaneous steam distillation-solvent extraction. The terpenes and terpenic derivatives were found in this fruit in major concentrations and were strong contributors to tropical fruit notes (Fig. 8.1). The aliphatic esters contributed much to its typical flavour. 

Volatile compounds isolated from strawberry guava fruit by simultaneous steam distillation-solvent extraction were identified by capillary gas chromatography-mass spectrometry (GC-MS) and were characterised sensorially by sniffing GC [52]. Terpenes and terpenic derivatives were identified and were shown to contribute much to the typical strawberry guava flavour. The presence of many aliphatic esters and terpenic compounds is thought to contribute to the unique flavour of the strawberry guava fruit. 

Another investigation reported the esters as the predominant volatile components of the Maradol variety (about 41% w/w of the total volatiles) [51]. The major representative compounds in the simultaneous steam distillation-solvent extraction were methyl butanoate and ethyl butanoate. Previous work described the esters as the predominant compounds among the volatiles papayas, for example, from Sri Lanka and Colombia had 52 and 63% of esters in the total volatiles respectively [25,41]. 

Polychlorobiphenyls were recovered from sediments in another investigation by steam distillation/solvent extraction, followed by enantioselective analysis using multidimensional electron capture gas chromatography [189]. 

Frenock, sodium-2,2,3,3-tetrafluoroproprionate Steam distillation, solvent extraction Mass fragmentography of l-benzyl-3-p-polytriazine derivative [477]... 

Carboxylic -acids, nitriles, aldehydes, ketones Steam - distillation, solvent extraction, ion exchange chromatography, GC [677]... 

Reaction of an aqueous solution of cystine with thiamin, glutamate, and ascorbic acid produces a complex mixture of compounds with an overall flavor resembling that of roasted meat. The reaction was carried out at 120 C for 0.5h at pH 5.0 in a closed system. The aroma compounds were isolated by means of the simultaneous steam distillation/solvent extraction method. The flavor concentrate was pre-separated by liquid chromatography on silica gel and subsequently analysed by GC and GC/MS. Unknown flavor components were... 

J. J. Richaid, G. A. Junk, Steam Distillation, Solvent Extraction,and Ion Exchange forDetermin ing PolarOiganics in Shale Process Wateis, Anal.Chem. 19S4, i6, 1625-1628. 

Teranishni, R., Keller, U., Flath, R.A., and Mon, T.R., Comparison of batchwise and continuous steam distillation—solvent extraction recovery of volatiles from oleoresin capsicum, African type (capsicum frutesens), J. Agric. Food Chem., 28, 156, 1980. 

Determination offline GC-ECD comparison steam distillation-solvent extraction (SDSE), SFE and Soxhlet extraction (SE) HCB recovery 100% SDSE, 98% SFE, 55% SE... 

Because of the formation of emulsions, the liquid-liquid extraction (LLE) of nonionic surfactants, e.g., APEO, is restricted to these less surface-active metabolites, i.e., APEO with one to three ethoxy units, APEC, and AP. Noncontinuous LLE of water samples with methylene chloride using a separatory funnel has been applied for NP and NPEO (one to three ethoxy units). In addition, an ultrasonic bath has been shown to be suitable for the LLE of APEOs and AEOs form water samples.Continuous LLE (percolation) has been successfully used for concentration of short-chained APEO and AP too. Steam distillation/solvent extraction using an apparatus designed by Veith and Kiwus " is a sophisticated method of concentrating steam-distillable AP and APEO (one to three ethoxy units) from water samples.AEOs have been efficiently extracted by combination of reflux hydrolysis with sulfuric acid and steam distillation with a Karlsruhe Apparatus. ... 

Extraction of APEO from solid matrices is performed in the same way as for LAS, i.e., Soxhlet extraction with methanol in combination with NaOH. In addition to methanol, methanokethylene chloride (1 and hexane" are used as extraction solvents. Steam distillation-solvent extraction is especially suitable for extraction of the APEO metabolites AP and APEO (one to three ethoxy units) from solid matrices. " ... 

Moldoveanu, S.C., J.L. Roles, and Q. Zha Study of the volatile compounds from tobacco using steam distillation-solvent extraction and other extraction techniques 50th Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 50, Paper No. 42, 1996, pp. 44-45. 

Peak numbers correspond to those in Figures i and 2 and Table II. RI, retention index. Average relative conccniratiop t. standard deviation (n=I2). SDE, simultaneous steam distillation-solvent extraction. DE, direct solvent extraction. Compound tentatively identified by comparing its mass spectrum to Wiley 13SK mass spectral database, Compound not previously identified in saffron. Compound positively identified as described in materials and methods. V trace. Compound tentatively identified by comparing its mass spectrum with published literature (II). nd. not detected. I.S., internal standard, N/A, not available, peak could not be resolved. 

Figure 1 Total ion chromaiogram of saffron volatiles isolated by simultaneous steam distillation-solvent extraction. Peak numbers correspond to those in Tables I and II and Figure 2.

Volatiles from red pepper or chills (Capsicum annuum and . frutescens) were isolated by steam distillation-solvent extraction methods. Compounds identified by gas chromatography-mass spectrometry are 17 alcohols, 20 carbonyl compounds, 14 carboxylic acids, 21 esters, 6 pyrazlnes, 14 terpene hydrocarbons, and 10 miscellaneous compounds. Only ten of these components have been reported previously in volatiles from peppers. Although the odor threshold method was applied, the characteristic red pepper odor was not fully correlated with identified constituents. The green bell pepper compound, 2-methoxy-3-lsobutylpyrazine, was found in both annuum and C. frutescens. 

Stashenko, E.E. Puertas, M. A. Combariza, M.Y. (19%). Volatile secondary metabolites from Spilanihes americana obtained by simultaneous steam distillation-solvent extraction and supercritical fluid extraction. Journal of Chromatography A, Vol.752, No.1-2, (November 1996), pp. 223-232, ISSN 0021-9673... 

Several methods have been employed (20) in the extraction of flavor volatiles from their chemical and physical bonds in the complex muscle matrix. These methods include steam distillation, solvent extraction, headspace analysis and supercritical fluid extraction. Each method had specific advantages and shortcomings when used in the isolation of numerous compound types such as carbonyls, sulfur-containing compounds such as thiols and thiazoles, pyrazines, furans, and pyrroles (27, 22). The mechanisms responsible for the formation of these flavor volatiles have been proposed and developed based on such experimentation (25, 24). 

In nature, essential oils having aroma and flavor are isolated from the various parts of the plants [39]. The essential oils for commercial utiUzation can be isolated using various methodologies which include steam distillation, solvent extraction, and expression [39, 44]. As reported previously, most of the plant essential oils exert potent biological efficacy [11, 35, 39, 45 7]. The antimicrobial or other biological activities of essential oils are directly correlated to the presence of their bioactive volatile components [11, 43, 48]. 

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