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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.
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Charakter proudění v náplňovém superkritickém extraktoru
Rochová, Kristina ; Sovová, Helena
This contribution provides a brief review on the effect of flow direction on SFE and reports our first experiments on axial dispersion measured in the course of extraction; this topic has not been sufficiently discussed in the literature yet. The flow pattern was examined by means of response to tracer injection and the results were expressed in the form of dimensionless variance S2 T,0. Tetracosane deposited on glass beads was extracted and presence of natural convection was observed when the flow was switched from downflow to upflow mode.
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Superkritická extrakce beta-sitosterolu ze slupek a listů rakytníku řešetlákového
Sajfrtová, Marie ; Sovová, Helena ; Bártlová, Milena
Extraction of beta-sitosterol with supercritical carbon dioxide from sea buckthorn pulp and leaves, a by-product of production of sea buckthorn juice, was studied. The effect of operation conditions on the yields and solubility of whole extract and its minor component beta-sitosterol was analysed in a series of experiments at pressures from 15 MPa to 28 MPa and temperatures 40 °C and 60 °C. The consecutively collected extract samples were analysed using HPLC. The selectivity of beta-sitosterol to major component was determined. The content of beta-sitosterol in both plant materials was obtained using Soxhlet extraction with hexane.
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Supercritical Extraction and Fractionation of Sea Buckthorn Oil: Beta-Sitosterol Selectivity to Oil
Rochová, Kristina ; Sovová, Helena
Sea buckthorn (Hippophae rhamnoides L.) contains large amounts of compounds important in the human diet and used in medicine, among others phytosterols, whose anticancer, anti-inflammatory and antibacterial effects have been proved. Phytosterols, particularly beta-sitosterol, occur in sea buckthorn oil. The oil was extracted from ground seeds with supercritical carbon dioxide at the temperatures 40 and 60 oC and pressures 15-28 MPa. Using HPLC analysis for beta-sitosterol, its selectivity to the oil was evaluated. The results enable us to increase the concentration of beta-sitosterol in the extract.
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Changes in the Fatty Acid Composition during Enzymatic Hydrolysis of Vegetable Oil
Sovová, Helena ; Zarevúcka, Marie
Hydrolysis of oil in a continuous-flow reactor packed with immobilised enzyme was integrated with oil extraction from blackcurrant seeds, using as solvent supercritical carbon dioxide at 40 oC and 15-28 MPa. The hydrolysate was fractionated into free fatty acids, combined fraction of di- and monoacylglycerols, and the unreacted oil (tricylglycerols). As a result of non-homogeneous distribution of some fatty acids at sn-positions in triacylglycerols and the action of 1,3-specific lipase Lipozyme, free fatty acids were enriched in palmitic, stearic, and alpha-linolenic acids, while gamma-linolenic and stearidonic acids were more concentrated in di- and monoacylglycerols.
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