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On the Extraction of Essential Oils by Supercritical Carbon Dioxide and its Influence on the Mesomorphic Phase Structures

da Cruz Francisco, José LU (2002)
Abstract (Swedish)
Popular Abstract in Swedish

Essentiella oljor från eukalyptusblad, Eucalyptus camaldulensis Dehn., utvunna genom destillation (HD) och superkritisk koldioxid (SC-CO2) -extraktion har jämförts. Utvalda huvudkomponenter från oljorna visar att komponenter i extrakt från SC-CO2 har övervägande högre molekylvikt än i dem från HD. Fysikalisk-kemiska egenskaper som molekylvikt, ångtryck och steriska faktorer, samt förhållanden vid SC-CO2 extraktion hänförs till skillnader i oljornas sammansättning. Miljöeffekter på kvalitén hos essentiella oljor utvunna från samma genotyp av eukalyptus behandlade med samma metoder diskuteras. Monoterpenerna 1,8-cineole, limonene och a-pinene, som finns i betydande mängd i olja från eukalyptusblad,... (More)
Popular Abstract in Swedish

Essentiella oljor från eukalyptusblad, Eucalyptus camaldulensis Dehn., utvunna genom destillation (HD) och superkritisk koldioxid (SC-CO2) -extraktion har jämförts. Utvalda huvudkomponenter från oljorna visar att komponenter i extrakt från SC-CO2 har övervägande högre molekylvikt än i dem från HD. Fysikalisk-kemiska egenskaper som molekylvikt, ångtryck och steriska faktorer, samt förhållanden vid SC-CO2 extraktion hänförs till skillnader i oljornas sammansättning. Miljöeffekter på kvalitén hos essentiella oljor utvunna från samma genotyp av eukalyptus behandlade med samma metoder diskuteras. Monoterpenerna 1,8-cineole, limonene och a-pinene, som finns i betydande mängd i olja från eukalyptusblad, blandningar av dessa, samt tre eukalyptusoljor från olika genotyper, E. dives, E. polybractea och E. Radiata, studerades med avseende på löslighet i komprimerad CO2 (SC-CO2 och flytande CO2, (LCO2). I allmänhet uppvisar rena blandningar högre löslighet i SC-CO2. Sammansättningen hos eukalyptusolja behandlad i LCO2 var jämförbar med den som erhölls i SC-CO2 vid högsta tryck och temperatur. Eftersom det finns polära lipider i eukalyptusblad är det viktigt att även studera interaktioner mellan lipider, vatten, SC-CO2 och essentiella oljor. Flytande kristallina egenskaper och extraherbarhet hos monoolein-vattensystem med SC-CO2 diskuteras. Den mest anmärkningsvärda observationen i undersökningen var förlusten av nativ kristallin struktur och det låga utbytet av monoolein i monoolein-vattensystem vid den högsta vattenhalten (18 vikt%) vid temperaturer mellan 35°C och 65°C. Dessa effekter förklaras med interaktioner mellan SC-CO2, vatten och monoolein, vilka leder till olika aktivitet hos vatten respektive monoolein i den aktuella fasen. Vidare har två modellsystem bestående av monoolein och vatten eller sojalecitin och vatten tillsammans med cineole och SC-CO2 använts för att studera fasbeteende. En generell observation är att den flytande kristallina strukturen kvarstår även vid överskott av SC-CO2. Det kan därför antas att lipidstrukturer i växtens vävnad kan finnas kvar även efter extraktion med SC-CO2 och bidra till de effekter som observerats vid extraheringsförsöken. (Less)
Abstract
A comparison of essential oils from leaves of Eucalyptus camaldulensis Dehn. obtained by hydrodistillation (HD) and supercritical carbon dioxide (SC-CO2) extraction is presented. Selected major components of the oils showed a predominance of higher molecular weight components in the SC-CO2 extracts than in those obtained by HD. Physico chemical properties such as molecular weight, vapour pressure of the components, steric factor as well as in oil composition. Discussions on environmental effects on the quality of the essential oils obtained on the same eucalyptus genotype treated by the same techniques are also presented. The monoterpenes 1,8-cineole, limonene and a-pinene, present in considerable amounts in eucalyptus leaf oils, as well... (More)
A comparison of essential oils from leaves of Eucalyptus camaldulensis Dehn. obtained by hydrodistillation (HD) and supercritical carbon dioxide (SC-CO2) extraction is presented. Selected major components of the oils showed a predominance of higher molecular weight components in the SC-CO2 extracts than in those obtained by HD. Physico chemical properties such as molecular weight, vapour pressure of the components, steric factor as well as in oil composition. Discussions on environmental effects on the quality of the essential oils obtained on the same eucalyptus genotype treated by the same techniques are also presented. The monoterpenes 1,8-cineole, limonene and a-pinene, present in considerable amounts in eucalyptus leaf oils, as well as their mixtures and three eucalyptus oils from different genotypes, namely E. dives, E. polybractea and E. radiata, were also studied with regard to their solubility in dense CO2 (SC-CO2 and LCO2). In general, pure compounds showed a higher solubility in SC-CO2. The composition SC-CO2 at the highest pressure and temperature. Since polar lipids are always present in eucalyptus leaves from which the oil is extracted, the interaction between such lipids, water, SC-CO2 and essential oils is important to study. First, liquid crystalline properties and the extractability of monoolein/water systems by supercritical carbon dioxide are discussed. The most remarkable observation in this study was the loss of the native mesomorphic structure at high temperatures and the low recovery of monoolein in monoolein/water systems within the highest (18wt%) water content at temperatures between 35 and 65°C. These effects are explained by the SC-CO2, water and monoolein interactions which lead to different water and monoolein activities in the phase present. Further, two model systems composed of monoolein/water or soybean lecithin/water, cineole and SC-CO2 are presented for studying the phase behaviour. Generally, it is observed that the liquid crystalline structure remain also in presence of surplus of SC-CO2. Hence, it can be assumed that lipid structures in the plant tissues may remain also during SC-CO2 extraction and contribute to the matrix effects observed in extraction trials. (Less)
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author
opponent
  • Professor Venskutonis, Petras Rimantas, Department of Food Technology, Kaunas University of Technology, Lithuania
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Natural oils, fats and waxes technology, Naturliga oljor, fetter, vax, Kemiteknik och kemisk teknologi, Chemical technology and engineering, Livsmedelsteknik, Food and drink technology, phase behavior, soybean lecithin, monoolein, cineole, terpenes, eucalyptus, extraction, Essential oils, supercritical carbon dioxide
pages
48 pages
publisher
Food Technology, Lund University
defense location
Lecture Hall A, Center for Chemistry and Chemical Engineering, Getingevägen 60, Lund, Entrance E
defense date
2002-04-05 10:15
external identifiers
  • other:ISRN: LUTKDH/TKL0-1041/1-48
language
English
LU publication?
yes
id
9227c4b0-4bb9-4fe4-935d-5849e6c78485 (old id 464495)
date added to LUP
2007-10-14 14:52:13
date last changed
2016-09-19 08:45:08
@phdthesis{9227c4b0-4bb9-4fe4-935d-5849e6c78485,
  abstract     = {A comparison of essential oils from leaves of Eucalyptus camaldulensis Dehn. obtained by hydrodistillation (HD) and supercritical carbon dioxide (SC-CO2) extraction is presented. Selected major components of the oils showed a predominance of higher molecular weight components in the SC-CO2 extracts than in those obtained by HD. Physico chemical properties such as molecular weight, vapour pressure of the components, steric factor as well as in oil composition. Discussions on environmental effects on the quality of the essential oils obtained on the same eucalyptus genotype treated by the same techniques are also presented. The monoterpenes 1,8-cineole, limonene and a-pinene, present in considerable amounts in eucalyptus leaf oils, as well as their mixtures and three eucalyptus oils from different genotypes, namely E. dives, E. polybractea and E. radiata, were also studied with regard to their solubility in dense CO2 (SC-CO2 and LCO2). In general, pure compounds showed a higher solubility in SC-CO2. The composition SC-CO2 at the highest pressure and temperature. Since polar lipids are always present in eucalyptus leaves from which the oil is extracted, the interaction between such lipids, water, SC-CO2 and essential oils is important to study. First, liquid crystalline properties and the extractability of monoolein/water systems by supercritical carbon dioxide are discussed. The most remarkable observation in this study was the loss of the native mesomorphic structure at high temperatures and the low recovery of monoolein in monoolein/water systems within the highest (18wt%) water content at temperatures between 35 and 65°C. These effects are explained by the SC-CO2, water and monoolein interactions which lead to different water and monoolein activities in the phase present. Further, two model systems composed of monoolein/water or soybean lecithin/water, cineole and SC-CO2 are presented for studying the phase behaviour. Generally, it is observed that the liquid crystalline structure remain also in presence of surplus of SC-CO2. Hence, it can be assumed that lipid structures in the plant tissues may remain also during SC-CO2 extraction and contribute to the matrix effects observed in extraction trials.},
  author       = {da Cruz Francisco, José},
  keyword      = {Natural oils,fats and waxes technology,Naturliga oljor,fetter,vax,Kemiteknik och kemisk teknologi,Chemical technology and engineering,Livsmedelsteknik,Food and drink technology,phase behavior,soybean lecithin,monoolein,cineole,terpenes,eucalyptus,extraction,Essential oils,supercritical carbon dioxide},
  language     = {eng},
  pages        = {48},
  publisher    = {Food Technology, Lund University},
  school       = {Lund University},
  title        = {On the Extraction of Essential Oils by Supercritical Carbon Dioxide and its Influence on the Mesomorphic Phase Structures},
  year         = {2002},
}