|
| |
|
|
Supercritical Fluid Fractionation for 20-Hydroxyecdysone Enrichment in Leuzea carthamoides Extract
Sajfrtová, Marie ; Maščeník, J. ; Sovová, Helena ; Bártlová, Milena
Supercritical fluid extraction of 20-hydroxyecdysone (20-HE) using pure and modified carbon dioxide from seeds of Leuzea carthamoides was studied. The effect of operation conditions on the yields of whole extract and its minor component 20-HE was analysed in a series of experiments at pressures from 30 MPa to 60 MPa, temperatures from 40 °C to 80 °C and modifier (ethanol, methanol and acetone) concentrations in CO2 0-19 wt. %. The consecutively collected extract fractions were analysed using HPLC. The efficiency of SFE in terms of 20-HE concentration in extract and yield was compared with the efficiency of Soxhlet extraction with ethanol.
|
|
|
Enrichment of Supercritical Extracts in beta-Sitosterol by Fractionation Process
Rochová, Kristina ; Sovová, Helena ; Sajfrtová, Marie ; Bártlová, Milena
The aim of this contribution was to use the extraction with supercritical CO2 coupled with fractionation of extract for preparation of extracts rich in beta-sitosterol. Phytosterols have been proved to lower serum cholesterol levels in humans and to have other benefit for human health. Supercritical extraction is a green method to separate such compounds from plants. Sea buckthorn seeds and sunflower seeds were extracted and a mathematical model was applied to determine separation factor of beta-sitosterol as minor component of extract. According to the obtained results, conditions of fractionation were set up. The most important enrichment of a part of extract from seeds with beta-sitosterol was achieved with fractionation in two separators (first separator kept at 15MPa and 50°C) and subsequent fractionation in time at the output of the second separator.
|
|
|
Separation Factors for Enrichment of Minor Components in Oils Extracted from Seeds with Supercritical CO2
Sovová, Helena
The present contribution shows that the same separation factors as for the oil fractionation in counter-current columns can be used to calculate the course of extraction of triacylglycerols and minor oil components in the initial period of fast extraction from crushed seed. Thus, the optimal conditions for minor component pre-concentration in extract or for removal of free fatty acids from the oil can be predicted. The values of separation factors for different minor components and for oils consisting mainly of C18 fatty acids are presented in dependence on the temperature, pressure, and CO2 density. The separation factors are based on both literature data and experimental data measured in our laboratory. The application of separation factors to calculate extraction yields of oil and its minor components in dependence on the amount of passed CO2 is presented, too.
|
|
| |
|
|
Enzymatic Reactions in Supercritical CO2
Rochová, Kristina ; Sovová, Helena ; Zarevúcka, Marie
Enzymatic hydrolysis of black current seed oil was carried out in supercritical CO2 (sc-CO2), in continuous flow reactor packed with immobilized enzyme Lipozyme. Black currant seed (Ribes nigrum L.) is rich in alfa- and gama-linolenic acids, bound in triacylglycerols, which have different dietetic effect. Selective hydrolysis allows preparation of fractions with different ratio of the two acids. Effect of reaction conditions (T=30–40°C, P=10-28 MPa) on reaction kinetics, composition of reaction mixture, selectivity and stability of enzyme. Results showed good stability of Lipozyme in sc-CO2. Alfa-Linolenic acid was unbound preferably due to enzyme stereospecificity. Combination of supercritical extraction with enzymatic reaction of extracted oil and subsequent fractionation of reaction mixture in two separators was tested in order to separate desired compounds. Further, stability of several enzymes prepared in our laboratory was tested in sc-CO2.
|
|
|
Alternative Plant Utilization for Obtaining of Significant Nature Substances: Can Weed Find a Utilization?
Wimmer, Zdeněk ; Sajfrtová, Marie ; Sovová, Helena ; Pavlík, Milan ; Svobodová, Hana ; Jurček, Ondřej ; Wimmerová, Martina
Numbers of compounds and their mixtures, which are produced by plants, can be obtained by extracting plant materials by supercritical fluids. Phytosterols and phytoecdysterotds represent an important family of these plant products. They can be used in a synthesis of supramolecular structures with possible importance for targeted effect of drugs or other biological(y active compounds. Target organisms for the compounds investigated are: (a) insects - pests and human food competitors, also important as model system in investigation of convenient application forms of biologically active compounds; (b) cell cultures used during basic pharmacological research. Supramolecular structures may form convenient matrices for practical application of the biologically active compounds. It has already been proved that numbers of medicinal or cultural plants produce important natural compounds. The present question has appeared to be answered, if so far inutile weeds may be turned into important sources of pro-drugs for disease treatments.
|
|
|
Extrakty z rostlin jako směsi a jejich předběžné dělení superkritickým CO2
Sovová, Helena ; Sajfrtová, Marie ; Rochová, Kristina
This work concerns supercritical extraction from plants, a semi-continuous process where solutes are extracted from a fixed bed of plant particles to a stream of supercritical CO2. Though the efficiency of control of extract composition in this one-equilibrium-stage process is lower than in the counter-current column, the composition of extract is affected substantially by extraction conditions. Further equilibrium stages are represented by the following separation of extract from solute in two or more separators adjusted to different pressures and temperatures, where the least soluble components precipitate first.
|
guest ::
