Person: Calvo Garrido, María Lourdes
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First Name
María Lourdes
Last Name
Calvo Garrido
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
Ingeniería Química
Identifiers
4 results
Search Results
Now showing 1 - 4 of 4
Item The Selective Supercritical Extraction of High-value Fatty Acids from Tetraselmis suecica using the Hansen Solubility Theory(Chemical engineering transactions, 2019) Calvo Garrido, Lourdes; Tirado Armesto, Diego Felipe; Rousset, Amandine; Calvo Garrido, María LourdesThe aim of this work was to test the utility of the Hansen theory to predict the best cosolvent for supercritical carbon dioxide (sc-CO2) to reach the selective extraction of fatty acids from Tetraselmis suecica. The order in the cosolvent power was established with five organic solvents used in food production: acetone, diethyl ether, ethanol, n-hexane and methanol. Predictions focused on the selective extraction of oleic, linoleic and αlinolenic acid. The cosolvent power depended on the fatty acid, but in general, the best cosolvent for the three target compounds was ethanol. Predictions were validated through equilibrium data and extraction yields from T. suecica. Operating at 305.15 K and 20 MPa, the extracted oil with the sc-CO2-ethanol (5 % mass fraction) mixture significantly improved the content of the target fatty acids compared with pure sc-CO2; e.g. the αlinolenic acid content was 16 % in the oil obtained with pure sc-CO2 while it was 25 % in the oil obtained with sc-CO2 + 5 % ethanol. However, the Hansen theory predicted that the miscibility enhancement of the fatty acids caused by increasing ethanol concentrations in the supercritical solvent mixture was not progressive. In fact, at high pressures and high ethanol concentrations, it was predicted up to less than half the miscibility enhancement.Item A selective extraction of hydroxytyrosol rich olive oil from alperujo(Journal of Food Engineering, 2019) Calvo Garrido, Lourdes; Tirado Armesto, Diego Felipe; Fuente, Esther de la; Calvo Garrido, María LourdesAlperujo, the solid-liquid waste generated by the current two-phase method of olive oil extraction, was dried, milled and treated with supercritical carbon dioxide (sc-CO2) to obtain a hydroxytyrosol (HT)-rich oil. At first, extraction rates were analysed as a function of operating variables and the pre-condition of the raw material. Samples with particle size diameter<0.80mm and in equilibrium moisture (1%) with the atmosphere, improved oil extraction yield almost 40% compared with samples with the whole range of particle sizes. Extraction yield improved with solvent flow rate, but a minimum residence time was required. The optimum was 0.18 kg h−1 (7.5 kg CO2 h−1 kg biomass−1). Higher pressures and lower temperatures resulted in higher extraction yields; at 30 MPa and 323 K the extraction curve slope was close to the theoretical oil solubility and the yield was 13%, like that obtained with n-hexane by Soxhlet (14%). However, the HPLC-DAD analysis identified higher HT concentration (1900 ppm) in the supercritical extracts at the highest temperature. Consequently, at 373 K, the total phenol content and the antioxidant capacity of the extracts was uppermost. No HT was found in the n-hexane extracts.Item The Hansen theory to choose the best cosolvent for supercritical CO2 extraction of β-carotene from Dunaliella salina(The Journal of Supercritical Fluids, 2019) Tirado Armesto, Diego Felipe; Calvo Garrido, María LourdesThe Hansen solubility theory was used to predict the best cosolvent for supercritical carbon dioxide (sc-CO2) to achieve the selective extraction of β-carotene from Dunaliella salina. Among four organic cosolvents, ethanol was predicted to be the best based on minima Ra values. The predictions were validated through equilibrium data and extraction curves from the microalgae. The addition of ethanol reduced the bubble pressures, and therefore increased the solubility of the β-carotene. With 5% mass fraction, at 318.15 K and 20 MPa, the extraction yield was 25 g carotenoids kg microalgae−1, much more than in pure sc-CO2 (6 g).Item Sterilization of Biological Weapons in Technical Clothing and Sensitive Material by High-Pressure CO2 and Water(Industrial & Engineering Chemistry Research, 2018) Calvo Garrido, Lourdes; Casas Huertas, Javier; Calvo Garrido, María LourdesThis work explores the effectiveness of highpressure CO2 on inactivation of Bacillus thuringiensis spores as a surrogate of B. anthracis spores (anthrax). The investigation was done in combatant equipment and several electronic devices. It was possible to sterilize this sensitive material by the environmentally friendly mixture formed by high-pressure CO2 and water. The presence of water in mass proportions ranging from 20 to 30% relative to the material was essential. However, it was continuously introduced in small amounts (<4% in relation to CO2), entrained by the CO2, so as not to have an adverse impact on materials. A low external pH enhanced the inactivation. Therefore, by using CO2 mixed with water acidified with citric acid to 3.3, the spores were killed at only 45 °C. The much less aggressive conditions of the treatment allowed preservation of the quality of the technical fabrics and the functionality of the electronic devices.