Primjena imobilizirane lipaze iz kvasca Candida antarctica u superkritičnoj fluidnoj ekstrakciji ulja od sjemenki boražine (Borago officinalis L.)

This study aims at the investigation of the possibilities to use immobilised lipase from Candida antarctica in supercritical fluid extraction (SFE) of borage (Borago officinalis L.) see doil. The first series of experiments was performed to measure the extract yields obtained with pure CO2 and with the added entrainer (ethanol). The yield increased more than twice after increasing the extraction pressure from 15 to 25 MPa. Further increase to 35 MPa was less effective. The effect of the entrainer was not significant in most cases. Palmitic (13.1–16.1 %), oleic (13.4–23.8 %), linoleic (33.8–48.4 %) and linolenic (8.8–16.3 %) acids were dominant in all extracted oils. Further experiments involved the use of enzyme. In this case the first extractor was loaded with ground borage seeds, the second one was filled with the enzyme. The total yield obtained at 15, 25 and 35 MPa was (8.8±0.2), (23.6±0.2) and (28.9±1.1) %, respectively. Thin layer chromatography (TLC) of fatty acid ethyl esters showed that the content of esters was higher in the extract obtained in one extractor system at 15 MPa, compared to 35 MPa.U ovom je radu istražena mogućnost primjene imobilizirane lipaze iz kvasca Candida antarctica pri superkritičnoj fluidnoj ekstrakciji ulja od sjemenki boražine (Borago officinalis L.). Prva serija pokusa provedena je radi mjerenja prinosa ekstrakta dobivenog s čistim CO2 i etanolom. Prinos je dvostruko i više porastao nakon povećanja tlaka s 15 na 25 MPa, dok povećanje na 35 MPa nije imalo učinka. Utjecaj otapala većinom je bio neznatan. U svim ekstrahiranim uljima prevladavale su palmitinska (13,1-16,1 %), oleinska (13,4-23,8 %), linolna (33,8-48,4 %) i linolenska (8,8-16,3 %) kiselina. Daljnje ispitivanje provedeno je pomoću enzima. Prvi ekstraktor napunjen je mljevenim sjemenkama boražine, a drugi enzimom. Ukupni prinos pri 15 MPa iznosio je (8,8±0,2) %, pri 25 MPa (23,6±0,2) %, a pri 35 MPa (28,9±1,1) %. Tankoslojnom kromatografijom etilnih estera masnih kiselina dokazano je da je veći udio estera u ekstraktu dobivenom pri 15 MPa nego sa 35 MPa

Solubility of three monoterpenes, their mixtures and eucalyptus leaf oils in dense carbon dioxide

The solubility of 1,8-cineole, alpha-pinene, limonene, their mixtures and the extract of eucalyptus leaf oils in supercritical carbon dioxide were determined using the dynamic method at 80, 100, 150, and 250 bar and 40 and 60 degreesC for each pressure. The results showed an increase in the solubility of all oils with an increase in pressure and a decrease with temperature. The mixtures of both pure blends as well as the eucalyptus oil extracts exhibited lower solubility than the pure single oil components in the same conditions. The oil of E. radiata exhibited a better separation of 1,8-cineole at 80 bar and 60 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved

Gelatinization of cassava, potato and wheat starches in supercritical carbon dioxide

The gelatinization of cassava, potato and wheat starches in supercritical carbon dioxide was investigated using light microscope. The starch was placed in a stainless steel chamber at atmospheric pressure and high CO2 pressures, 8 and 30 MPa as well as at 8 MPa N-2 and the gelatinization degree observed by light microscopy. The results showed that both pressure and supercritical fluid affected the gelatinization degree. Cassava and potato starches showed a lowering of the gelatinization temperatures at 8 MPa and an increasing at 30 MPa as compared with the gelatinization degree at atmospheric pressure. For wheat starch, the decrease in the gelatinization temperature occurred in the same direction as the pressure increased, in comparison with the atmospheric pressure conditions. However, between the two applied pressures, there was a larger increase of the gelatinization temperature at 30 MPa than at 8 MPa. The effect of hydrostatic pressure component of the CO2 was evaluated by using N-2 at 8 MPa. The replacement of CO2 by N-2 at 8 MPa increased the gelatinization temperature for all the studied starches compared with the atmospheric conditions. (C) 2002 Elsevier Science B.V. All rights reserved

Supercritical fluid extraction of borage (Borago officinalis L.) seeds with pure CO2 and its mixture with caprylic acid methyl ester

The influence of different pressures of CO2 and the addition of caprylic acid methyl ester as an entrainer was studied for the extraction process of borage seed. The increase of CO2 pressure from 100 to 350 bar resulted in the increase in extract yield from 0.14 to 24.29% (w/w) while the changes in the extract composition were not so considerable. The highest solubility of pure caprylic acid methyl ester in dense CO2 was determined at 100 and 300 bar (approximately 1 g of ester in 1 g of CO2). The addition of this entrainer increased the yield of pure extract up to 47.8 times at 100 bar, 2.4 times at 200 and 300 bar. Due to the high solubility of caprylic acid methyl ester at the lower (100 bar) pressure it is easy to separate the entrainer, which constituted only 4.22% of the total borage seed extract. (C) 2002 Elsevier Science B.V. All rights reserved

Comparison of oil from Nigella damascena seed recovered by pressing, conventional solvent extraction and carbon dioxide extraction

Nigella damascena seeds were extracted by cold press, in a Soxhlet apparatus and with CO2 The yield obtained with liquid CO2 was only 10.57%. EtOH (1%) increased the yield by 50%. CO2-extracts were separated into the 2 fractions. The yield in the first fraction increased 2 times by increasing the pressure from 150 to 350 bar. EtOH (1%) increased the yield 2 times at 150 bar. Linoleic acid was the major fatty acid (43.71 to 50.83%), followed by oleic (14.87 to 23.65%), stearic (15.07 to 23.24%), and palmitic (10.13 to 12.07%) acids. Elemenes (21.38% to 29.16%) were the most abundant volatile constituents, free fatty acids constituted from 35.04% to 51.18%, the majority being linoleic (32.83 to 40.58) (Range for linoleic should be 24.51 to 40.58%-see Table 3) and oleic acids (4.96 to 13.32)

Dextran modifications of polysulfone UF-membranes: Streaming potential and BSA fouling characteristics

Polysulfone ultrafiltration membranes were modified with dextran, dextran sulfate and diethylaminoethyl (DEAE) dextran. The behavior of the modified membranes towards static adsorption of bovine serum albumin (BSA) was investigated in the pH range 3-7. The modified membranes showed lower flux losses after protein adsorption than unmodified membranes. The plain dextran was considered to be the best choice of the three as a modifying agent. Streaming potentials were measured for DEAE dextran and dextran T500 modified membranes as a function of pH. The isoelectric points of the membranes were 5.9 and 4.6, respectively. Titration data for DEAE and dextran T500 are also presented. The modification of membranes with dextrans of different molecular weight average indicated that the shorter dextran molecules (Dextran T10) gave a better result than the larger ones (Dextran T500)

Phase behavior of the monoolein-water system - The effects of addition of the hydrocarbon 1,8-cineole and supercritical carbon dioxide

The results of a study on the phase behavior of the monoolein/water system with the addition of the hydrocarbon 1,8-cineole (C10H18O) and supercritical carbon dioxide at 15 MPa is presented. To two mixtures consisting of 9 and 18 wt.% water in monoolein, 5, 10, and 20 wt.% cineole were added and heated to between 35 and 80 degreesC at atmospheric pressure and in the presence of supercritical carbon dioxide. The phase changes were followed by deuterium nuclear magnetic resonance (H-2 NMR), light microscopy, and ocular inspection. The mesomorphic structures developed in the 9 wt.% water sample suffered little change due to the presence of the supercritical carbon dioxide. However, in the mixture with 18 wt.% water, the native phase structures were dramatically affected and an isotropic fluid phase developed. The addition of cineole has lowered the LC-L-alpha --> LC-H-Pi phase transition in the samples with 9 and 18 wt.% water in monoolein. The surplus of supercritical carbon dioxide in the samples has resulted in similar developments. Regardless of the amount of cineole present in the system, only the isotropic fluid phase was observed in the samples with 18 wt.% water in monoolein. (C) 2004 Elsevier B.V. All rights reserved