Optimization of supercritical carbon dioxide extraction of antioxidants from roasted wheat germ based on yield, total phenolic and tocopherol contents, and antioxidant activities of the extracts

Gelmez, Niluefer
Kincal, N. Suzan
Yener, Meryem Esra
Effects of pressure (148-602 bar), temperature (40-60 degrees C) and time (10-60 min) on antioxidant (phenolics and tocopherols) contents and antioxiclant activities of supercritical carbon dioxide (SC-CO2) extracts of roasted wheat germ were determined, using central composite rotatable design. The dependent variables were yield (%), total phenolic contents (TPC, mg gallic acid equivalent (GAE)/g extract), total tocopherol contents (TTC, mg tocopherol/g extract) and antioxidant activities (AA, mg scavenged 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH,)/g extract) of the extracts. The antioxiclant purity of the extracts (TPC, TTC and AA) were high at extraction conditions where the extraction yield was low (148-165 bar, 40-60 degrees C and 10 min). The optimum extraction conditions found by maximizing all the dependent variables were 336 bar, 58 degrees C and 10 min, where 5.3% yield, 6 mg GAE phenolics/g extract, 6.7 mg tocopherol/g extract and 57.3 mg scavenged DPPH./g extract was predicted. The tocopherol yield under these conditions corresponded to almost complete recovery.


Optimization of supercritical CO2 extraction of Thymbra spicata oil
Sonsuzer, S; Şahin, Serpil; Yılmaz, Levent (Elsevier BV, 2004-07-01)
The supercritical fluid extraction (SFE) of aroma compounds from Thymbra spicata was studied. Response surface methodology (RSM) was used to optimize the parameters of the supercritical fluid extraction. Independent variables were temperature (40, 50 and 60 degreesC), pressure (80, 100 and 120 bar) and time (30, 60 and 90 min). Dependent variables were yield, monoterpene, sesquiterpene and oxygenated monoterpene contents.
Enhanced solubility of siloxy-modified polyhedral oligomeric silsesquioxanes in supercritical carbon dioxide
Demirtas, Cansu; Dilek Hacıhabiboğlu, Çerağ (Elsevier BV, 2019-01-01)
Alkyl siloxy functionalization increases the solubility of polyhedral oligomeric silsesquioxanes (POSS) in supercritical carbon dioxide over an order of magnitude compared to its counterpart with fluoroalkyl groups. The studied component, octatrimethylsiloxy POSS also exhibits higher solubility than other previously studied POSS types with various alkyl and methacryl groups. The octatrimethylsiloxy POSS-CO2 solid-vapor equilibrium curves have been constructed at temperatures between 308 and 328 K by measuri...
Phase behavior of 1,3,5-tri-tert-butylbenzene-carbon dioxide binary system
Dilek Hacıhabiboğlu, Çerağ; Gulari, Esin (Elsevier BV, 2008-01-01)
1,3,5-tri-tert-butylbenzene (TTBB) is solid at ambient conditions, and has substantial solubility in liquid and supercritical carbon dioxide. We present the phase behavior of TTBB-CO2 binary system at temperatures between 298 and 328 K and at pressures up to 20 MPa. Phase diagrams showing the liquid-vapor, solid-liquid and solid-vapor equilibrium envelopes are constructed by pressure-volume-temperature measurements in a variable-volume sapphire cell. TTBB is highly soluble in CO2 over a wide range of compos...
Calculation of molar volume as a function of temperature close to the melting point in benzene
Yurtseven, Hasan Hamit (Walter de Gruyter GmbH, 2007-01-01)
We study here the temperature dependence of the molar volume for constant pressures in benzene close to the melting point. By analyzing the experimental data for the thermal expansivity at various pressures in benzene, we calculate the molar volumes as functions of temperature in this system. Our calculations show that discontinuities in the molar volume decrease as the melting temperatures increase along the melting line when the constant pressures vary from 70.5 MPa to 175.2 MPa, as also observed experime...
Phase Behavior of Carbon Dioxide and Polyhedral Oligomeric Silsesquioxanes with Two Different Functional Groups
Dumanlilar, Beril; Dilek Hacıhabiboğlu, Çerağ (Elsevier BV, 2020-09-01)
Phase behavior of carbon dioxide and polyhedral oligomeric silsesquioxanes (POSS) modified with two different functional groups is studied in the temperature range of 308-323 K, up to 22 MPa. Different than the common types, one of the eight functional groups attached to the Si atoms of these POSS is a CO2-philic functional group, methacryl, while the rest are branched alkyl chains, either isooctyl (MIOPOSS) or isobutyl (MIBPOSS). Methacrylisobutyl POSS-CO2 binary system exhibits pressure-induced melting te...
Citation Formats
N. Gelmez, N. S. Kincal, and M. E. Yener, “Optimization of supercritical carbon dioxide extraction of antioxidants from roasted wheat germ based on yield, total phenolic and tocopherol contents, and antioxidant activities of the extracts,” JOURNAL OF SUPERCRITICAL FLUIDS, pp. 217–224, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40845.